2,309 research outputs found
Dental Amalgam Restorations and Children’s Neuropsychological Function: The New England Children’s Amalgam Trial
BACKGROUND: A concern persists that children’s exposure to mercury vapor from dental amalgams produces neurotoxicity. OBJECTIVE: Our goal was to compare the neuropsychological function of children, without prior exposure to dental amalgam, whose caries were repaired using either dental amalgam or mercury-free composite materials. METHODS: We conducted a randomized controlled trial involving 534 6- to 10-year-old urban and rural children who were assessed yearly for 5 years using a battery of tests of intelligence, achievement, language, memory, learning, visual–spatial skills, verbal fluency, fine motor function, problem solving, attention, and executive function. RESULTS: Although the mean urinary mercury concentration was greater among children in the amalgam group than the composite group (0.9 vs. 0.6 μg/g creatinine), few significant differences were found between the test scores of children in the two groups. The differences found were inconsistent in direction. Analyses using two cumulative exposure indices—surface years of amalgam and urinary mercury concentration—produced similar results. CONCLUSIONS: Exposure to elemental mercury in amalgam at the levels experienced by the children who participated in the trial did not result in significant effects on neuropsychological function within the 5-year follow-up period
A Possible Detection of Occultation by a Proto-planetary Clump in GM Cephei
GM Cep in the young (~4 Myr) open cluster Trumpler 37 has been known to be an
abrupt variable and to have a circumstellar disk with very active accretion.
Our monitoring observations in 2009-2011 revealed the star to show sporadic
flare events, each with brightening of < 0.5 mag lasting for days. These
brightening events, associated with a color change toward the blue, should
originate from an increased accretion activity. Moreover, the star also
underwent a brightness drop of ~1 mag lasting for about a month, during which
the star became bluer when fainter. Such brightness drops seem to have a
recurrence time scale of a year, as evidenced in our data and the photometric
behavior of GM Cep over a century. Between consecutive drops, the star
brightened gradually by about 1 mag and became blue at peak luminosity. We
propose that the drop is caused by obscuration of the central star by an
orbiting dust concentration. The UX Orionis type of activity in GM Cep
therefore exemplifies the disk inhomogeneity process in transition between
grain coagulation and planetesimal formation in a young circumstellar disk.Comment: In submission to the Astrophysical Journal, 4 figure
Synchrotron x-ray study of lattice vibrations in CdCr2O4
Using inelastic x-ray scattering we have investigated lattice vibrations in a
geometric frustrated system CdCr2O4 that upon cooling undergoes a spin-Peierls
phase transition at TN = 7.8 K from a cubic and paramagnetic to a tetragonal
and Neel state. Phonon modes measured around Brillouin zone boundaries show
energy shifts when the transition occurs. Our analysis shows that the shifting
can be understood as the ordinary effects of the lowering of the crystal
symmetry
Ellagic Acid Recovery by Solid State Fermentation of Pomegranate Wastes by Aspergillus niger and Saccharomyces cerevisiae : a Comparison
Abstract: Fermentation in solid state culture (SSC) has been the focus of increasing interest because of its potential for industrial applications. In previous studies SSC of pomegranate wastes by Aspergillus niger has been extensively developed and optimized for the recovery of ellagic acid (EA), a high value bioactive. In this study we comparatively investigated the SSC of powdered pomegranate husks by A. niger and Saccharomyces cerevisiae and evaluated the recovery yields of EA by an ultrasound and microwave-assisted 7:3 water/ethanol extraction. Surprisingly enough, the yields obtained by S. cerevisiae fermentation (4% w/w) were found 5-fold higher than those of the A. niger fermented material, with a 10-fold increase with respect to the unfermented material. The EA origin was traced by HPLC analysis that showed a significant decrease in the levels of punicalagin isomers and granatin B and formation of punicalin following fermentation. Other extraction conditions that could warrant a complete solubilization of EA were evaluated. Using a 1:100 solid to solvent ratio and DMSO as the solvent, EA was obtained in 4% yields from S. cerevisiae fermented husks at a high purity degree. Hydrolytic treatment of S. cerevisiae fermented pomegranate husks aorded a material freed of the polysaccharides components that gave recovery yields of EA up to 12% w/w
Lowering IceCube's energy threshold for point source searches in the Southern Sky
Observation of a point source of astrophysical neutrinos would be a "smoking gun" signature of a cosmic-ray accelerator. While IceCube has recently discovered a diffuse flux of astrophysical neutrinos, no localized point source has been observed. Previous IceCube searches for point sources in the southern sky were restricted by either an energy threshold above a few hundred TeV or poor neutrino angular resolution. Here we present a search for southern sky point sources with greatly improved sensitivities to neutrinos with energies below 100 TeV. By selecting charged-current ν μ interacting inside the detector, we reduce the atmospheric background while retaining efficiency for astrophysical neutrino-induced events reconstructed with sub-degree angular resolution. The new event sample covers three years of detector data and leads to a factor of 10 improvement in sensitivity to point sources emitting below 100 TeV in the southern sky. No statistically significant evidence of point sources was found, and upper limits are set on neutrino emission from individual sources. A posteriori analysis of the highest-energy (~100 TeV) starting event in the sample found that this event alone represents a 2.8σ deviation from the hypothesis that the data consists only of atmospheric background.Fil: Aartsen, M. G.. University of Adelaide; AustraliaFil: Abraham, K.. Technische Universität München; AlemaniaFil: Ackermann, M.. Deutsches Elektronen-Synchrotron; AlemaniaFil: Adams, J.. University Of Canterbury; Nueva ZelandaFil: Aguilar, J. A.. Université Libre de Bruxelles; BélgicaFil: Golup, Geraldina Tamara. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Wallace, A.. University of Adelaide; AustraliaFil: Wallraff, M.. Rwth Aachen University; AlemaniaFil: Wandkowsky, N.. University of Wisconsin; Estados UnidosFil: Weaver, Ch.. University of Alberta; CanadáFil: Wendt, C.. University of Wisconsin; Estados UnidosFil: Westerhoff, S.. University of Wisconsin; Estados UnidosFil: Whelan, B. J.. University of Adelaide; AustraliaFil: Whitehorn, N.. University of California at Berkeley; Estados UnidosFil: Wickmann, S.. Rwth Aachen University; AlemaniaFil: Wiebe, K.. Johannes Gutenberg Universitat Mainz; AlemaniaFil: Wiebusch, C. H.. Rwth Aachen University; AlemaniaFil: Wille, L.. University of Wisconsin; Estados UnidosFil: Williams, D. R.. University of Alabama at Birmingahm; Estados UnidosFil: Wills, L.. Drexel University; Estados UnidosFil: Wissing, H.. University of Maryland; Estados UnidosFil: Wolf, M.. Stockholms Universitet; SueciaFil: Wood, T. R.. University of Alberta; CanadáFil: Woschnagg, K.. University of California at Berkeley; Estados UnidosFil: Xu, D. L.. University of Wisconsin; Estados UnidosFil: Xu, X. W.. Southern University; Estados UnidosFil: Xu, Y.. Stony Brook University; Estados UnidosFil: Yanez, J. P.. Deutsches Elektronen-Synchrotron; AlemaniaFil: Yodh, G.. University of California at Irvine; Estados UnidosFil: Yoshida, S.. Chiba University; JapónFil: Zoll, M.. Stockholms Universitet; Sueci
Clinical Utility of microRNAs in Exhaled Breath Condensate as Biomarkers for Lung Cancer.
This study represents a novel proof of concept of the clinical utility of miRNAs from exhaled breath condensate (EBC) as biomarkers of lung cancer (LC). Genome-wide miRNA profiling and machine learning analysis were performed on EBC from 21 healthy volunteers and 21 LC patients. The levels of 12 miRNAs were significantly altered in EBC from LC patients where a specific signature of miR-4507, miR-6777-5p and miR-451a distinguished these patients with high accuracy. Besides, a distinctive miRNA profile between LC adenocarcinoma and squamous cell carcinoma was observed, where a combined panel of miR-4529-3p, miR-8075 and miR-7704 enabling discrimination between them. EBC levels of miR-6777-5p, 6780a-5p and miR-877-5p predicted clinical outcome at 500 days. Two additional miRNA signatures were also associated with other clinical features such as stage and invasion status. Dysregulated EBC miRNAs showed potential target genes related to LC pathogenesis, including CDKN2B, PTEN, TP53, BCL2, KRAS and EGFR. We conclude that EBC miRNAs might allow the identification, stratification and monitorization of LC, which could lead to the development of precision medicine in this and other respiratory diseases
Theoretical study of lepton events in the atmospheric neutrino experiments at SuperK
Super-Kamiokande has reported the results for the lepton events in the
atmospheric neutrino experiment. These results have been presented for a 22.5kT
water fiducial mass on an exposure of 1489 days, and the events are divided
into sub-GeV, multi-GeV and PC events. We present a study of nuclear medium
effects in the sub-GeV energy region of atmospheric neutrino events for the
quasielastic scattering, incoherent and coherent pion production processes, as
they give the most dominant contribution to the lepton events in this energy
region. We have used the atmospheric neutrino flux given by Honda et al. These
calculations have been done in the local density approximation. We take into
account the effect of Pauli blocking, Fermi motion, Coulomb effect,
renormalization of weak transition strengths in the nuclear medium in the case
of the quasielastic reactions. The inelastic reactions leading to production of
leptons along with pions is calculated in a - dominance model by
taking into account the renormalization of properties in the nuclear
medium and the final state interaction effects of the outgoing pions with the
residual nucleus. We present the results for the lepton events obtained in our
model with and without nuclear medium effects, and compare them with the Monte
Carlo predictions used in the simulation and the experimentally observed events
reported by the Super-Kamiokande collaboration.Comment: 23 pages, 13 figure
Nivel de conocimientos y su relación con las actitudes y prácticas preventivas del Zika
Objetivo. Este estudio descriptivo correlacional de corte transversal; se realizó para determinar el nivel de conocimientos y su relación con las actitudes y prácticas preventivas del Zika en el distrito de Chepen - La Libertad Perú. 2017. Materiales y métodos. Se aplicó un cuestionario sobre conocimiento, actitudes y prácticas preventivas en una muestra de 284 personas adultas, con una edad promedio de 37 años. Resultados. Los resultados demuestran que el nivel de conocimiento general sobre zika fue regular en un 79% y bueno en un 21%. En cuanto a las prácticas preventivas de zika más comunes que realizan los habitantes de Chepén, un 83% mencionan que lavan frecuentemente los depósitos de agua, 77% usan cepillo y detergente para lavar los depósitos con agua y 75% coloca una tapa sobre los depósitos con agua. Conclusiones. El nivel de conocimiento tiene una relación significativa con las practicas preventivas del zika (p0.05)
Do solar neutrinos decay?
Despite the fact that the solar neutrino flux is now well-understood in the
context of matter-affected neutrino mixing, we find that it is not yet possible
to set a strong and model-independent bound on solar neutrino decays. If
neutrinos decay into truly invisible particles, the Earth-Sun baseline defines
a lifetime limit of \tau/m \agt 10^{-4} s/eV. However, there are many
possibilities which must be excluded before such a bound can be established.
There is an obvious degeneracy between the neutrino lifetime and the mixing
parameters. More generally, one must also allow the possibility of active
daughter neutrinos and/or antineutrinos, which may partially conceal the
characteristic features of decay. Many of the most exotic possibilities that
presently complicate the extraction of a decay bound will be removed if the
KamLAND reactor antineutrino experiment confirms the large-mixing angle
solution to the solar neutrino problem and measures the mixing parameters
precisely. Better experimental and theoretical constraints on the B
neutrino flux will also play a key role, as will tighter bounds on absolute
neutrino masses. Though the lifetime limit set by the solar flux is weak, it is
still the strongest direct limit on non-radiative neutrino decay. Even so,
there is no guarantee (by about eight orders of magnitude) that neutrinos from
astrophysical sources such as a Galactic supernova or distant Active Galactic
Nuclei will not decay.Comment: Very minor corrections, corresponds to published versio
Growth of Synechococcus sp. immobilized in chitosan with different times of contact with NaOH
The thickness of the walls of the capsules of chitosan-immobilized Synechococcus cultures was dependent on the time of contact with NaOH and was directly related to culture growth. After an initial lag phase, probably caused by cell damage, the capsules obtained after 80 s in a 0.1 N NaOH solution showed better growth than that of free cell cultures (6.9 and 5.2 divisions in 10 days, respectively)
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