Nitrate and drinking water from private wells: Will there be an epidemic of cancers of the digestive tract, urinary bladder and thyroid?

Purpose: To estimate the nitrate levels in private wells located in different parts of Enugu and discuss the future health implications following chronic ingestion of well water.Materials and Methods: The map of Enugu was used to divide the city into many 25 units, using grid lines 1 cm apart. Cluster sampling method was used to collect samples. These samples were sent to two laboratories for estimation of nitrate levels. The people drawing water from the different wells were interviewed to determine what they used the water for.Result: The subjects who were interviewed said they ingested the water. The nitrate levels found in these wells (median value of 31 mg/L) were  significantly higher than the internationally accepted levels of nitrate in water for ingestion, (P < 0.0001).Conclusion: High nitrate levels drinking water is dangerous to health and can cause methemoglobinemia in children. It may also increase cancer risk in adults because nitrate is endogenously reduced to nitrite and subsequent nitrosation reactions give rise to N‑nitroso compounds (NOCs), which are highly carcinogenic and can act systemically.Key words: Cancer, contamination, nitrates, private well

Acoustic black holes for relativistic fluids

We derive a new acoustic black hole metric from the Abelian Higgs model. In the non-relativistic limit, while the Abelian Higgs model becomes the Ginzburg-Landau model, the metric reduces to an ordinary Unruh type. We investigate the possibility of using (type I and II) superconductors as the acoustic black holes. We propose to realize experimental acoustic black holes by using spiral vortices solutions from the Navier-stokes equation in the non-relativistic classical fluids.Comment: 16 pages. typos corrected, contents expande

Efficient All Top-k Computation - A Unified Solution for All Top-k, Reverse Top-k and Top-m Influential Queries

published_or_final_versio

Cell cycle G2/M arrest through an S phase-dependent mechanism by HIV-1 viral protein R

<p>Abstract</p> <p>Background</p> <p>Cell cycle G2 arrest induced by HIV-1 Vpr is thought to benefit viral proliferation by providing an optimized cellular environment for viral replication and by skipping host immune responses. Even though Vpr-induced G2 arrest has been studied extensively, how Vpr triggers G2 arrest remains elusive.</p> <p>Results</p> <p>To examine this initiation event, we measured the Vpr effect over a single cell cycle. We found that even though Vpr stops the cell cycle at the G2/M phase, but the initiation event actually occurs in the S phase of the cell cycle. Specifically, Vpr triggers activation of Chk1 through Ser³⁴⁵phosphorylation in an S phase-dependent manner. The S phase-dependent requirement of Chk1-Ser³⁴⁵phosphorylation by Vpr was confirmed by siRNA gene silencing and site-directed mutagenesis. Moreover, downregulation of DNA replication licensing factors Cdt1 by siRNA significantly reduced Vpr-induced Chk1-Ser³⁴⁵phosphorylation and G2 arrest. Even though hydroxyurea (HU) and ultraviolet light (UV) also induce Chk1-Ser³⁴⁵phosphorylation in S phase under the same conditions, neither HU nor UV-treated cells were able to pass through S phase, whereas <it>vpr</it>-expressing cells completed S phase and stopped at the G2/M boundary. Furthermore, unlike HU/UV, Vpr promotes Chk1- and proteasome-mediated protein degradations of Cdc25B/C for G2 induction; in contrast, Vpr had little or no effect on Cdc25A protein degradation normally mediated by HU/UV.</p> <p>Conclusions</p> <p>These data suggest that Vpr induces cell cycle G2 arrest through a unique molecular mechanism that regulates host cell cycle regulation in an S-phase dependent fashion.</p

Biochemical observations in rats fed with cycads, Nigerian-like and western-like folic acid supplemented diets

Alterations in antioxidant enzymes and lipid peroxidation was studied in 90 Wistar albino rats exposed to cycads and fed with Nigerian-like and western-like diets supplemented with folic acid. The animals were divided into three diet classes of 30 animals each. One group was fed with a wholly compounded Nigerian-like diet (NLD) which was low in protein and high in carbohydrate and fiber. Another group was fed with a western like diet (WLD) which was high in protein and fat, while the third group of animals was fed with a normal diet which served as the control class. The animals of each class were further divided into three subgroups of ten rats each. In each subclass, one group received the diet alone; another group received the diet and cycads, while the third group received the diet and folic acid. Low levels of catalase, feed intake and faecal output was observed with experimental animals fed NLD as compared to WLD and normal diet (ND) fed animals. High levels of antioxidant enzymes: super oxide dismutase, catalase and glutathione reductase as well as low levels of lipid peroxidation was observed with the addition of folic acid to the diets of experimental rats. These results suggest the role of folic acid in diet and colon carcinogenesis.Key words: Antioxidant enzymes, cycads, diets, folic acid, lipid peroxidation

RF Modeling Using Parallel Codes ACE3P for the 400-MHz Parallel-Bar/Ridged-Waveguide Compact Crab Cavity for the LHC HiLumi Upgrade

Schemes utilizing crab cavities to achieve head-on beam-beam collisions were proposed for the LHC HiLumi upgrade. These crabbing schemes require that the crab cavities be compact in order to fit into the tight spacing available in the existing LHC beamlines at the location where the crab cavities will be installed. Under the support of US LARP program, Old Dominion University and SLAC have joint efforts to develop a 400-MHz compact superconducting crab cavity to meet the HiLumi upgrade requirements. In this paper, we will present the RF modeling and analysis of a parallel-bar/ridged-waveguide shaped 400-MHz compact cavity design that can be used for both the horizontal and vertical crabbing schemes. We will also present schemes for HOM damping and multipacting analysis for such a design

Depressive and post-traumatic stress symptoms following termination of pregnancy in South African women: A longitudinal study measuring the effects of chronic burden, crisis support and resilience

 Background. Termination of pregnancy (TOP) remains a controversial issue, regardless of legislation. Access to services as well as psychological effects may vary across the world.Objectives and methods. To better understand the psychological effects of TOP, this study describes the circumstances of 102 women who underwent a TOP from two socioeconomic sites in Johannesburg, South Africa, one serving women with few economic resources and the other serving women with adequate resources. The relationship between demographic characteristics, resilience and symptoms of posttraumatic stress disorder (PTSD) and depression before, 1 month after and 3 months after the procedure was also examined.Results. Time since TOP, age, chronic burden, resilience and the interaction of site with religion and site with chronic burden were significant. In addition, site differences were found for religion and chronic burden in predicting depression scores. Women from both sites had significant decreases in depression scores over time. The interaction of time with site was not significant. Higher chronic burden scores correlated with higher depression scores. No variables were significant in the bivariate analysis for PTSD.Conclusion. Resilience, religion and chronic burden emerge as significant variables in women undergoing a first-trimester TOP, and warrant further assessment in studies of this nature

Response of spectral reflectances and vegetation indices on varying juniper cone densities

Juniper trees are widely distributed throughout the world and are common sources of allergies when microscopic pollen grains are transported by wind and inhaled. In this study, we investigated the spectral influences of pollen-discharging male juniper cones within a juniper canopy. This was done through a controlled outdoor experiment involving ASD FieldSpec Pro Spectroradiometer measurements over juniper canopies of varying cone densities. Broadband and narrowband spectral reflectance and vegetation index (VI) patterns were evaluated as to their sensitivity and their ability to discriminate the presence of cones. The overall aim of this research was to assess remotely sensed phenological capabilities to detect pollen-bearing juniper trees for public health applications. A general decrease in reflectance values with increasing juniper cone density was found, particularly in the Green (545-565 nm) and NIR (750-1,350 nm) regions. In contrast, reflectances in the shortwave-infrared (SWIR, 2,000 nm to 2,350 nm) region decreased from no cone presence to intermediate amounts (90 g/m2) and then increased from intermediate levels tothe highest cone densities (200 g/m2). Reflectance patterns in the Red (620-700 nm) were more complex due to shifting contrast patterns in absorptance between cones and juniper foliage, where juniper foliage is more absorbing than cones only within the intense narrowband region of maximum chlorophyll absorption near 680 nm. Overall, narrowband reflectances were more sensitive to cone density changes than the equivalent MODIS broadbands. In all VIs analyzed, there were significant relationships with cone density levels, particularly with the narrowband versions and the two-band vegetation index (TBVI) based on Green and Red bands, a promising outcome for the use of phenocams in juniper phenology trait studies. These results indicate that spectral indices are sensitive to certain juniper phenologic traits that can potentially be used for juniper cone detection in support of public health applications. © 2013 by the authors

Infrared spectroscopy of small-molecule endofullerenes

Hydrogen is one of the few molecules which has been incarcerated in the molecular cage of C$_{60}$ and forms endohedral supramolecular complex H$_2$@C$_{60}$. In this confinement hydrogen acquires new properties. Its translational motion becomes quantized and is correlated with its rotations. We applied infrared spectroscopy to study the dynamics of hydrogen isotopologs H$_2$, D$_2$ and HD incarcerated in C$_{60}$. The translational and rotational modes appear as side bands to the hydrogen vibrational mode in the mid infrared part of the absorption spectrum. Because of the large mass difference of hydrogen and C$_{60}$ and the high symmetry of C$_{60}$ the problem is identical to a problem of a vibrating rotor moving in a three-dimensional spherical potential. The translational motion within the C$_{60}$ cavity breaks the inversion symmetry and induces optical activity of H$_2$. We derive potential, rotational, vibrational and dipole moment parameters from the analysis of the infrared absorption spectra. Our results were used to derive the parameters of a pairwise additive five-dimensional potential energy surface for H$_2$@C$_{60}$. The same parameters were used to predict H$_2$ energies inside C$_{70}$[Xu et al., J. Chem. Phys., {\bf 130}, 224306 (2009)]. We compare the predicted energies and the low temperature infrared absorption spectra of H$_2$@C$_{70}$.Comment: Updated author lis