930 research outputs found
Aluminum-titanium hydride-boron carbide composite provides lightweight neutron shield material
Inexpensive lightweight neutron shield material has high strength and ductility and withstands high internal heat generation rates without excessive thermal stress. This composite material combines structural and thermal properties of aluminum, neutron moderating properties of titanium hydride, and neutron absorbing characteristics of boron carbide
Legislation and Education as Strategies to Reduce Behavioral Health Risk Factors in the State of Nebraska
In the interest of improving health care planning and practice, this paper exami~es legislation and educational strategies designed to reduce behavioral health risk factors in the state of Nebraska and the United States. The growing problem of modifying health behavior in the nation and Nebraska is reviewed, including trends in seat belt use, drinking and driving, smoking, hypertension, obesity, and sedentary lifestyle. Nebraska\u27s rate of death associated with these risk factors is higher than the national average. Several of the strategies which Nebraska and the United States have implemented are reviewed.
Legislation to reduce the prevalence of seat belt nonuse, drinking and driving, and smoking, is one prevention strategy which has been developed and implemented in both Nebraska and the United States, although levels of enforcement and type of penalties vary.
Despite legislative action, many people still find ways to violate the laws without punishment; therefore, education plays a critical role in prevention. If programs are targeted to the right demographic groups with the right methodology, legislation may become less important in controlling or modifying human behavior. The most recent national goals and objectives (Healthy People, 1991) developed by the federal government indicated that, although the rate of increase in the number of deaths which can be attributed to poor health behavior is rising more slowly than in previous years, there is still an increase, which ideally should be reversed by the year 2000.
Over the last few decades, both legislative and educational strategies have produced some moderate changes in the overall health of our nation, but with more resources devoted to planning and implementing legislative and educational strategies, Nebraska and the nation overall demonstrate potential for successfully addressing the problems and achieving the goal of preventing deaths due to poor health behavior. Since the financial impact on our health care system and the economy is a very critical issue at the present time, improvements in health care planning and practice, as well as further research and evaluation are warranted.
Adviser: Professor Gordon Schol
Spitzer observations of a gravitationally lensed quasar, QSO 2237+0305
The four-image gravitationally lensed quasar QSO 2237+0305 is microlensed by
stars in the lens galaxy. The amplitude of microlensing variability can be used
to infer the relative size of the quasar as a function of wavelength; this
provides a test of quasar models. Toward this end, we present Spitzer Space
Telescope Infrared Spectrograph and Infrared Array Camera (IRAC) observations
of QSO 2237+0305, finding the following. (1) The infrared (IR) spectral energy
distribution (SED) is similar to that of other bright radio-quiet quasars,
contrary to an earlier claim. (2) A dusty torus model with a small opening
angle fits the overall shape of the IR SED well, but the quantitative agreement
is poor due to an offset in wavelength of the silicate feature. (3) The flux
ratios of the four lensed images can be derived from the IRAC data despite
being unresolved. We find that the near-IR fluxes are increasingly affected by
microlensing toward shorter wavelengths. (4) The wavelength dependence of the
IRAC flux ratios is consistent with the standard quasar model in which an
accretion disk and a dusty torus both contribute near 1 micron in the rest
frame. This is also consistent with recent IR spectropolarimetry of nearby
quasars
Recommended from our members
Are Complementary Therapies and Integrative Care Cost-Effective? A Systematic Review of Economic Evaluations
Objective: A comprehensive systematic review of economic evaluations of complementary and integrative medicine (CIM) to establish the value of these therapies to health reform efforts. Data sources PubMed, CINAHL, AMED, PsychInfo, Web of Science and EMBASE were searched from inception through 2010. In addition, bibliographies of found articles and reviews were searched, and key researchers were contacted. Eligibility criteria for selecting studies Studies of CIM were identified using criteria based on those of the Cochrane complementary and alternative medicine group. All studies of CIM reporting economic outcomes were included. Study appraisal methods All recent (and likely most cost-relevant) full economic evaluations published 2001–2010 were subjected to several measures of quality. Detailed results of higher-quality studies are reported. Results: A total of 338 economic evaluations of CIM were identified, of which 204, covering a wide variety of CIM for different populations, were published 2001–2010. A total of 114 of these were full economic evaluations. And 90% of these articles covered studies of single CIM therapies and only one compared usual care to usual care plus access to multiple licensed CIM practitioners. Of the recent full evaluations, 31 (27%) met five study-quality criteria, and 22 of these also met the minimum criterion for study transferability (‘generalisability’). Of the 56 comparisons made in the higher-quality studies, 16 (29%) show a health improvement with cost savings for the CIM therapy versus usual care. Study quality of the cost-utility analyses (CUAs) of CIM was generally comparable to that seen in CUAs across all medicine according to several measures, and the quality of the cost-saving studies was slightly, but not significantly, lower than those showing cost increases (85% vs 88%, p=0.460). Conclusions: This comprehensive review identified many CIM economic evaluations missed by previous reviews and emerging evidence of cost-effectiveness and possible cost savings in at least a few clinical populations. Recommendations are made for future studies
Alternative mechanism for bacteriophage adsorption to the motile bacterium Caulobacter crescentus
2D and 3D cryo-electron microscopy, together with adsorption kinetics assays of Ï•Cb13 and Ï•CbK phage-infected Caulobacter crescentus, provides insight into the mechanisms of infection. Ï•Cb13 and Ï•CbK actively interact with the flagellum and subsequently attach to receptors on the cell pole. We present evidence that the first interaction of the phage with the bacterial flagellum takes place through a filament on the phage head. This contact with the flagellum facilitates concentration of phage particles around the receptor (i.e., the pilus portals) on the bacterial cell surface, thereby increasing the likelihood of infection. Phage head filaments have not been well characterized and their function is described here. Phage head filaments may systematically underlie the initial interactions of phages with their hosts in other systems and possibly represent a widespread mechanism of efficient phage propagation
Electronic shielding by closed shells in salts of thulium
Electronic shielding by closed electron shells has been investigated in salts of trivalent thulium, by measuring the temperature dependence of the nuclear quadrupole splitting of the 8.42-keV gamma transition in Tm169. The measurements were performed by using the technique of recoilless nuclear resonance absorption. The nuclear quadrupole interaction was studied for Tm3+ ions in thulium ethyl sulfate, thulium oxide, and thulium trifluoride within a temperature range from 9.6 to 1970°K. The interpretation of the experimental data in terms of the contributions of distorted closed electron shells to the quadrupole interaction yields values for electronic shielding factors. The results lead to amounts of 10% or less for the atomic Sternheimer factor RQ. The experiments also reveal substantial shielding of the 4f electrons from the crystal electric field, expressed by the shielding factor σ2. Values of 250 and 130 are obtained for the ratio (1-γ∞)/(1-σ2) for thulium ethyl sulfate and thulium oxide, respectively, where γ∞ is the lattice Sternheimer factor
Arecoline induced disruption of expression and localization of the tight junctional protein ZO-1 is dependent on the HER 2 expression in human endometrial Ishikawa cells
<p>Abstract</p> <p>Background</p> <p>Approximately 600 million people chew Betel nut, making this practice the fourth most popular oral habit in the world. Arecoline, the major alkaloid present in betel nut is one of the causative agents for precancerous lesions and several cancers of mouth among those who chew betel nut. Arecoline can be detected in the human embryonic tissue and is correlated to low birth weight of newborns whose mothers chew betel nut during pregnancy, suggesting that arecoline can induce many systemic effects. However, few reports exist as to the effects of arecoline in human tissues other than oral cancer cell lines. Furthermore, in any system, virtually nothing is known about the cellular effects of arecoline treatment on membrane associated signaling components of human cancer cells.</p> <p>Results</p> <p>Using the human Ishikawa endometrial cancer cell line, we investigated the effects of arecoline on expression, localization and functional connections between the ZO-1 tight junction protein and the HER2 EGF receptor family member. Treatment of Ishikawa cells with arecoline coordinately down-regulated expression of both ZO-1 and HER2 protein and transcripts in a dose dependent manner. Biochemical fractionation of cells as well as indirect immunofluorescence revealed that arecoline disrupted the localization of ZO-1 to the junctional complex at the cell periphery. Compared to control transfected cells, ectopic expression of exogenous HER2 prevented the arecoline mediated down-regulation of ZO-1 expression and restored the localization of ZO-1 to the cell periphery. Furthermore, treatment with dexamethasone, a synthetic glucocorticoid reported to up-regulate expression of HER2 in Ishikawa cells, precluded arecoline from down-regulating ZO-1 expression and disrupting ZO-1 localization.</p> <p>Conclusion</p> <p>Arecoline is known to induce precancerous lesions and cancer in the oral cavity of betel nut users. The arecoline down-regulation of ZO-1 expression and subcellular distribution suggests that arecoline potentially disrupts cell-cell interactions mediated by ZO-1, which may play a role in arecoline-mediated carcinogenesis. Furthermore, our study has uncovered the dependency of ZO-1 localization and expression on HER2 expression, which has therefore established a new cellular link between HER2 mediated signaling and apical junction formation involving ZO-1.</p
Upregulation of Defensins in Burn Sheep Small Intestine
Objective: The aim of this study was to visualize and localize the sheep antimicrobials, β-defensins 1, 2, and 3, (SBD-1, SBD-2, SBD-3), sheep neutrophil defensin alpha (SNP-1), and the cathelicidin LL-37 in sheep small intestine after burn injury, our hypothesis being that these compounds would be upregulated in an effort to overcome a compromised endothelial lining. Response to burn injury includes the release of proinflammatory cytokines and systemic immune suppression that, if untreated, can progress to multiple organ failure and death, so protective mechanisms have to be initiated and implemented. Methods: Tissue sections were probed with antibodies to the antimicrobials and then visualized with fluorescently labeled secondary antibodies and subjected to fluorescence deconvolution microscopy and image reconstruction. Results: In both the sham and burn samples, all the aforementioned antimicrobials were seen in each of the layers of small intestine, the highest concentration being localized to the epithelium. SBD-2, SBD-3, and SNP-1 were upregulated in both enterocytes and Paneth cells, while SNP-1 and LL-37 showed increases in both the inner circular and outer longitudinal muscle layers of the muscularis externa following burn injury. Each of the defensins, except SBD-1, was also seen in between the muscle layers of the externa and while burn caused slight increases of SBD-2, SBD-3, and SNP-1 in this location, LL-37 content was significantly decreased. Conclusion: That while each of these human antimicrobials is present in multiple layers of sheep small intestine, SBD-2, SBD-3, SNP-1, and LL-37 are upregulated in the specific layers of the small intestine
- …