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Demonstrating Agreement between Radio and Fluorescence Measurements of the Depth of Maximum of Extensive Air Showers at the Pierre Auger Observatory. PHYSICAL REVIEW LETTERS 2024; 132:021001. [PMID: 38277596 DOI: 10.1103/physrevlett.132.021001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 10/16/2023] [Accepted: 10/24/2023] [Indexed: 01/28/2024]
Abstract
We show, for the first time, radio measurements of the depth of shower maximum (X_{max}) of air showers induced by cosmic rays that are compared to measurements of the established fluorescence method at the same location. Using measurements at the Pierre Auger Observatory we show full compatibility between our radio and the previously published fluorescence dataset, and between a subset of air showers observed simultaneously with both radio and fluorescence techniques, a measurement setup unique to the Pierre Auger Observatory. Furthermore, we show radio X_{max} resolution as a function of energy and demonstrate the ability to make competitive high-resolution X_{max} measurements with even a sparse radio array. With this, we show that the radio technique is capable of cosmic-ray mass composition studies, both at Auger and at other experiments.
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Discovery of Gamma Rays from the Quiescent Sun with HAWC. PHYSICAL REVIEW LETTERS 2023; 131:051201. [PMID: 37595214 DOI: 10.1103/physrevlett.131.051201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 01/27/2023] [Accepted: 06/23/2023] [Indexed: 08/20/2023]
Abstract
We report the first detection of a TeV γ-ray flux from the solar disk (6.3σ), based on 6.1 years of data from the High Altitude Water Cherenkov (HAWC) observatory. The 0.5-2.6 TeV spectrum is well fit by a power law, dN/dE=A(E/1 TeV)^{-γ}, with A=(1.6±0.3)×10^{-12} TeV^{-1} cm^{-2} s^{-1} and γ=3.62±0.14. The flux shows a strong indication of anticorrelation with solar activity. These results extend the bright, hard GeV emission from the disk observed with Fermi-LAT, seemingly due to hadronic Galactic cosmic rays showering on nuclei in the solar atmosphere. However, current theoretical models are unable to explain the details of how solar magnetic fields shape these interactions. HAWC's TeV detection thus deepens the mysteries of the solar-disk emission.
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Plasma Aβ42/40 and cognitive variability are associated with cognitive function in Black Americans: Findings from the AA-FAIM cohort. ALZHEIMER'S & DEMENTIA (NEW YORK, N. Y.) 2023; 9:e12414. [PMID: 37752907 PMCID: PMC10519622 DOI: 10.1002/trc2.12414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 06/25/2023] [Indexed: 09/28/2023]
Abstract
Introduction It is critical to develop more inclusive Alzheimer's disease (AD) research protocols to ensure that historically excluded groups are included in preclinical research and have access to timely diagnosis and treatment. If validated in racialized groups, plasma AD biomarkers and measures of subtle cognitive dysfunction could provide avenues to expand diversity in preclinical AD research. We sought to evaluate the utility of two easily obtained, low-burden disease markers, plasma amyloid beta (Aβ)42/40, and intra-individual cognitive variability (IICV), to predict concurrent and longitudinal cognitive performance in a sample of Black adults. Methods Two hundred fifty-seven Black participants enrolled in the African Americans Fighting Alzheimer's in Midlife (AA-FAIM) study underwent at least one cognitive assessment visit; a subset of n = 235 had plasma samples. Baseline IICV was calculated as the standard deviation across participants' z scores on five cognitive measures: Rey Auditory Verbal Learning Test Delayed Recall, Trail Making Test Parts A and B (Trails A and B), and Boston Naming Test. Using mixed effects regression models, we compared concurrent and longitudinal models to baseline plasma Aβ42/40 or IICV by age interactions. PrecivityAD assays quantified baseline plasma Aβ42/40. Results IICV was associated with concurrent/baseline performance on several outcomes but did not modify associations between age and cognitive decline. In contrast, plasma Aβ42/40 was unrelated to baseline cognitive performance, but a pattern emerged in interactions with age in longitudinal models of Trails A and B and Rey Auditory Verbal Learning Test total learning trials. Although not significant after correcting for multiple comparisons, low Aβ42/40 was associated with faster cognitive declines over time. Discussion Our results are promising as they extend existing findings to an Black American sample using low-cost, low-burden methods that can be implemented outside of a research center, thus supporting efforts for inclusive AD biomarker research.
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Limits to Gauge Coupling in the Dark Sector Set by the Nonobservation of Instanton-Induced Decay of Super-Heavy Dark Matter in the Pierre Auger Observatory Data. PHYSICAL REVIEW LETTERS 2023; 130:061001. [PMID: 36827568 DOI: 10.1103/physrevlett.130.061001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 11/30/2022] [Accepted: 12/14/2022] [Indexed: 06/18/2023]
Abstract
Instantons, which are nonperturbative solutions to Yang-Mills equations, provide a signal for the occurrence of quantum tunneling between distinct classes of vacua. They can give rise to decays of particles otherwise forbidden. Using data collected at the Pierre Auger Observatory, we search for signatures of such instanton-induced processes that would be suggestive of super-heavy particles decaying in the Galactic halo. These particles could have been produced during the post-inflationary epoch and match the relic abundance of dark matter inferred today. The nonobservation of the signatures searched for allows us to derive a bound on the reduced coupling constant of gauge interactions in the dark sector: α_{X}≲0.09, for 10^{9}≲M_{X}/GeV<10^{19}. Conversely, we obtain that, for instance, a reduced coupling constant α_{X}=0.09 excludes masses M_{X}≳3×10^{13} GeV. In the context of dark matter production from gravitational interactions alone, we illustrate how these bounds are complementary to those obtained on the Hubble rate at the end of inflation from the nonobservation of tensor modes in the cosmological microwave background.
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Diabetes is related to cognition but not plasma amyloid‐β 42/40 in an African American cohort. Alzheimers Dement 2022. [DOI: 10.1002/alz.067925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Assessing trust and research attitudes in Blacks/African Americans following a personalized vs less personalized community approach. Alzheimers Dement 2022. [DOI: 10.1002/alz.068033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Trajectories of plasma Aβ42/40 among African Americans: Preliminary results from the African American Fighting Alzheimer’s in Midlife (AA‐FAIM) study. Alzheimers Dement 2022. [DOI: 10.1002/alz.066942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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An examination of baseline plasma Aβ42/40 and intra‐individual cognitive variability (IICV) associations with longitudinal cognitive change in a Black Cohort: Data from the African Americans Fighting Alzheimer’s in Midlife (AA‐FAIM) study. Alzheimers Dement 2022. [DOI: 10.1002/alz.061055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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9
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Plasma Aβ42/40 and PET amyloid associations among late‐middle‐aged African Americans: Preliminary results from the AA‐FAIM study. Alzheimers Dement 2022. [DOI: 10.1002/alz.069390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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10
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Reusable composite membranes for highly efficient chromium removal from real water matrixes. CHEMOSPHERE 2022; 307:135922. [PMID: 35940413 DOI: 10.1016/j.chemosphere.2022.135922] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 07/29/2022] [Accepted: 07/30/2022] [Indexed: 06/15/2023]
Abstract
Natural or industrial hexavalent chromium water pollution continues to be a worldwide unresolved threat. Today, there is intense research on new active and cost-effective sorbents for Cr(VI), but most still exhibit a critical limitation: their powdered nature makes their recovery from water cost and energy consuming. In this work, Al(OH)3, MIL-88-B(Fe), and UiO-66-NH2 Cr(VI) sorbents were immobilized into a poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) polymeric substrate to develop an easily reactivable and reusable water filtering technology. The immobilization of the sorbents into the PVDF-HFP porous matrix modified the macro and meso-porous structure of the polymeric matrix, tuning in parallel its wettability. Although a partial blocking of the Cr(VI) adsorptive capacity was observed for of Al(OH)3 and MIL-88-B(Fe) when immobilized into composite membranes, PVDF-HFP/UiO-66-NH2 filter (i) exceeded the full capacity of the non-immobilized sorbent to trap Cr(VI), (ii) could be reactivated and reusable, and (iii) it was fully functional when applied in real water effluents.
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Racial Differences in Associations of Cognitive Health Status With Happiness, Helplessness, and Hopelessness Among Older Adults: An Exploratory Study. Front Aging Neurosci 2022; 14:890404. [PMID: 35645778 PMCID: PMC9130928 DOI: 10.3389/fnagi.2022.890404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Accepted: 04/12/2022] [Indexed: 01/25/2023] Open
Abstract
Background The relationship between healthy and positive aging and dementia and cognitive impairment has received limited attention in the field of aging. Affect impacts cognitive changes and processes, and cognitive impairment is associated with affective comorbidities. The purpose of the study was to examine (a) whether happiness, helplessness, and hopelessness are linked to cognitive health status, and (b) whether these associations differ by race. Methods Participants were enrollees in the Wisconsin Alzheimer's Disease Research Center's Clinical Core (ADRC). Average age at baseline was 60.85 (SD = 8.65), 73.70 (SD = 8.02), and 73.80 (SD = 9.59) years for cognitively normal individuals, individuals with MCI, and individuals with dementia, respectively. Results In the full sample, chi-square test results revealed associations between Cognitive Health Status (CHS) and (a) happiness, χ2(2) = 6.06, p < 0.05, (b) helplessness, χ2(2) = 6.44, p < 0.05, and (c) hopelessness, χ2(2) = 14.11, p < 0.01. Conclusion This study provides support for the association of both positive and negative affect with cognitive health status in middle- to older-aged adults.
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Multifunctional hybrid membranes for photocatalytic and adsorptive removal of water contaminants of emerging concern. CHEMOSPHERE 2022; 293:133548. [PMID: 34999100 DOI: 10.1016/j.chemosphere.2022.133548] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 01/02/2022] [Accepted: 01/04/2022] [Indexed: 06/14/2023]
Abstract
This work focuses on the combination of multifunctional photocatalytic and adsorbent materials in a unique polymeric membrane. For this purpose, Au/TiO2 and Y2(CO3)3 nanoparticles were immobilised onto a poly (vinylidene fluoride-hexafluoropropylene), (PVDF-HFP) membrane, and the physical-chemical characterisation of these materials was performed, as well as pollutant removal efficiency. An efficient TiO2 functionalisation with gold nanoparticles was achieved, endowing these particles with the capability to absorb visible radiation absorption. A favourable porous structure was obtained for the membranes, with an average pore size of 4 μm, and the nanoparticles immobilisation did not alter the chemical properties of the polymeric membrane. The produced hybrid materials, including both the Au/TiO2 and Y2(CO3)3 nanoparticles, presented an efficiency of 57% in the degradation of norfloxacin (5 mg/L) under ultraviolet radiation for 120 min, 80% under visible radiation for 300 min, and 58% in arsenic adsorption for 240 min. These membranes represent a new multifunctional platform for removing several pollutants, which may allow their incorporation in more efficient and less energy-consuming water treatment processes favouring its application, even in low energy resources countries.
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Waist‐hip ratio as a moderator of the effects of hormone therapy on cognitive function in recently menopausal women. Alzheimers Dement 2021. [DOI: 10.1002/alz.056539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Measurement of the Fluctuations in the Number of Muons in Extensive Air Showers with the Pierre Auger Observatory. PHYSICAL REVIEW LETTERS 2021; 126:152002. [PMID: 33929235 DOI: 10.1103/physrevlett.126.152002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 01/28/2021] [Accepted: 02/12/2021] [Indexed: 06/12/2023]
Abstract
We present the first measurement of the fluctuations in the number of muons in extensive air showers produced by ultrahigh energy cosmic rays. We find that the measured fluctuations are in good agreement with predictions from air shower simulations. This observation provides new insights into the origin of the previously reported deficit of muons in air shower simulations and constrains models of hadronic interactions at ultrahigh energies. Our measurement is compatible with the muon deficit originating from small deviations in the predictions from hadronic interaction models of particle production that accumulate as the showers develop.
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Crystal morphology control of synthetic giniite for enhanced photo-Fenton activity against the emerging pollutant metronidazole. CHEMOSPHERE 2021; 262:128300. [PMID: 33182084 DOI: 10.1016/j.chemosphere.2020.128300] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 09/07/2020] [Accepted: 09/08/2020] [Indexed: 06/11/2023]
Abstract
Metronidazole (MNZ) is a recalcitrant antibiotic with toxic and carcinogenic effects in aquatic environments. In this work, Fe5(PO4)4(OH)3·2H2O (giniite) particles were synthesised with three different alkaline cations (Li+, Na+ and K+) and used as Fenton catalysts for MNZ removal. It is shown that the addition of different cations during the hydrothermal synthesis process promote different morphologies from asterisk-like to flower-like and branches-like, maintaining the crystalline structure of pure giniite. The photo-Fenton activity of these particles was then evaluated through the degradation of MNZ under sunlight radiation for 9 h. The results indicate that the alkaline cation has a predominant role in the photo-Fenton efficiency, as demonstrated by the superior degradation efficiencies of Na@giniite particles (91.2% and 72.5% with giniite concentration of 0.2 g L-1 and 0.07 g L-1, respectively), related with its high surface area (10.7 m2 g-1). Thus, it is demonstrated the suitability of Na@giniite particles as Fenton catalyst for MNZ removal from water.
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Association of cognitive health status with happiness, helplessness and hopelessness in different races. Alzheimers Dement 2020. [DOI: 10.1002/alz.037170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Incident MCI and dementia in Hispanic and non‐Hispanic whites: Implications for ethnic comparisons of risk in Alzheimer’s Disease Center data. Alzheimers Dement 2020. [DOI: 10.1002/alz.044126] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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18
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Assessing functional disability in individuals with MCI and dementia. Alzheimers Dement 2020. [DOI: 10.1002/alz.042126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Features of the Energy Spectrum of Cosmic Rays above 2.5×10^{18} eV Using the Pierre Auger Observatory. PHYSICAL REVIEW LETTERS 2020; 125:121106. [PMID: 33016715 DOI: 10.1103/physrevlett.125.121106] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 07/31/2020] [Indexed: 06/11/2023]
Abstract
We report a measurement of the energy spectrum of cosmic rays above 2.5×10^{18} eV based on 215 030 events. New results are presented: at about 1.3×10^{19} eV, the spectral index changes from 2.51±0.03(stat)±0.05(syst) to 3.05±0.05(stat)±0.10(syst), evolving to 5.1±0.3(stat)±0.1(syst) beyond 5×10^{19} eV, while no significant dependence of spectral features on the declination is seen in the accessible range. These features of the spectrum can be reproduced in models with energy-dependent mass composition. The energy density in cosmic rays above 5×10^{18} eV is [5.66±0.03(stat)±1.40(syst)]×10^{53} erg Mpc^{-3}.
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Photocatalytic and antimicrobial multifunctional nanocomposite membranes for emerging pollutants water treatment applications. CHEMOSPHERE 2020; 250:126299. [PMID: 32113095 DOI: 10.1016/j.chemosphere.2020.126299] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 02/15/2020] [Accepted: 02/20/2020] [Indexed: 06/10/2023]
Abstract
Emerging pollutants represent a new global problem for water quality. As these compounds get into the environment, they cause severe threats to aquatic environments and human health and are typically resistant to conventional wastewater treatments. In this work, TiO2 nanoparticles surface was functionalized with silver (Ag) nanoparticles, and solvent cast and electrospun membranes of poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) were prepared with different concentrations of TiO2 and Ag-TiO2 to produce a multifunctional material. The photocatalytic activity of the nanocomposites was evaluated through the degradation of norfloxacin under ultraviolet (UV) and visible radiation. It is shown that nanocomposites with Ag-TiO2 show the highest degradation efficiencies: 64.2% under UV and 80.7% under visible radiation, for 90 and 300 min, respectively. Furthermore, the recyclability of the membranes has also been demonstrated. Finally, it is shown the antimicrobial activity of the nanocomposite membranes, demonstrating the suitability of the Ag-TiO2/PVDF-HFP nanocomposites as multifunctional photocatalytic and antimicrobial membranes for water remediation applications.
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Measurements of the Timescale and Conformational Space of AMPA Receptor Desensitization. Biophys J 2020; 119:206-218. [PMID: 32559412 PMCID: PMC7335938 DOI: 10.1016/j.bpj.2020.05.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 04/06/2020] [Accepted: 05/29/2020] [Indexed: 12/19/2022] Open
Abstract
Ionotropic glutamate receptors are ligand-gated ion channels that mediate excitatory synaptic transmission in the central nervous system. Desensitization of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid subtype after glutamate binding appears critical for brain function and involves rearrangement of the ligand binding domains (LBDs). Recently, several full-length structures of ionotropic glutamate receptors in putative desensitized states were published. These structures indicate movements of the LBDs that might be trapped by cysteine cross-links and metal bridges. We found that cysteine mutants at the interface between subunits A and C and lateral zinc bridges (between subunits C and D or A and B) can trap freely desensitizing receptors in a spectrum of states with different stabilities. Consistent with a close approach of subunits during desensitization processes, the introduction of bulky amino acids at the A-C interface produced a receptor with slow recovery from desensitization. Further, in wild-type GluA2 receptors, we detected the population of a stable desensitized state with a lifetime around 1 s. Using mutations that progressively stabilize deep desensitized states (E713T and Y768R), we were able to selectively protect receptors from cross-links at both the diagonal and lateral interfaces. Ultrafast perfusion enabled us to perform chemical modification in less than 10 ms, reporting movements associated to desensitization on this timescale within LBD dimers in resting receptors. These observations suggest that small disruptions of quaternary structure are sufficient for fast desensitization and that substantial rearrangements likely correspond to stable desensitized states that are adopted relatively slowly on a timescale much longer than physiological receptor activation.
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Constraints on Lorentz Invariance Violation from HAWC Observations of Gamma Rays above 100 TeV. PHYSICAL REVIEW LETTERS 2020; 124:131101. [PMID: 32302173 DOI: 10.1103/physrevlett.124.131101] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 02/07/2020] [Accepted: 03/04/2020] [Indexed: 06/11/2023]
Abstract
Because of the high energies and long distances to the sources, astrophysical observations provide a unique opportunity to test possible signatures of Lorentz invariance violation (LIV). Superluminal LIV enables the decay of photons at high energy. The high altitude water Cherenkov (HAWC) observatory is among the most sensitive gamma-ray instruments currently operating above 10 TeV. HAWC finds evidence of 100 TeV photon emission from at least four astrophysical sources. These observations exclude, for the strongest of the limits set, the LIV energy scale to 2.2×10^{31} eV, over 1800 times the Planck energy and an improvement of 1 to 2 orders of magnitude over previous limits.
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Association between enrollment factors and incident cognitive impairment in Blacks and Whites: Data from the Alzheimer's Disease Center. Alzheimers Dement 2019; 15:1533-1545. [PMID: 31601516 PMCID: PMC6925619 DOI: 10.1016/j.jalz.2019.07.015] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Revised: 07/02/2019] [Accepted: 07/14/2019] [Indexed: 01/06/2023]
Abstract
INTRODUCTION We examined the influence of enrollment factors demonstrated to differ by race on incident mild cognitive impairment and dementia using Alzheimer's Disease Center data. METHODS Differences in rates of incident impairment between non-Latino Whites and Blacks (n = 12,242) were examined with age-at-progression survival models. Models included race, sex, education, source of recruitment, health factors, and family history of dementia. RESULTS No significant race differences in progression were observed in cognitively unimpaired participants. In those with mild cognitive impairment at baseline, Whites evidenced greater risk for progression than Blacks. Enrollment factors, for example, referral source, were significantly related to progression. DISCUSSION The finding that Blacks demonstrated lower rate of progression than Whites is contrary to the extant literature. Nested-regression analyses suggested that selection-related factors, differing by race, may account for these findings and influence our ability to accurately estimate risk for progression. It is potentially problematic to make racial comparisons using Alzheimer's Disease Center data sets.
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Data-driven estimation of the invisible energy of cosmic ray showers with the Pierre Auger Observatory. Int J Clin Exp Med 2019. [DOI: 10.1103/physrevd.100.082003] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Extended gamma-ray sources around pulsars constrain the origin of the positron flux at Earth. Science 2018; 358:911-914. [PMID: 29146808 DOI: 10.1126/science.aan4880] [Citation(s) in RCA: 211] [Impact Index Per Article: 35.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 10/09/2017] [Indexed: 11/02/2022]
Abstract
The unexpectedly high flux of cosmic-ray positrons detected at Earth may originate from nearby astrophysical sources, dark matter, or unknown processes of cosmic-ray secondary production. We report the detection, using the High-Altitude Water Cherenkov Observatory (HAWC), of extended tera-electron volt gamma-ray emission coincident with the locations of two nearby middle-aged pulsars (Geminga and PSR B0656+14). The HAWC observations demonstrate that these pulsars are indeed local sources of accelerated leptons, but the measured tera-electron volt emission profile constrains the diffusion of particles away from these sources to be much slower than previously assumed. We demonstrate that the leptons emitted by these objects are therefore unlikely to be the origin of the excess positrons, which may have a more exotic origin.
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Inferences on mass composition and tests of hadronic interactions from 0.3 to 100 EeV using the water-Cherenkov detectors of the Pierre Auger Observatory. Int J Clin Exp Med 2017. [DOI: 10.1103/physrevd.96.122003] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Abstract
Neurotransmitters trigger synaptic currents by activating ligand-gated ion channel receptors. Whereas most neurotransmitters are efficacious agonists, molecules that activate receptors more weakly-partial agonists-also exist. Whether these partial agonists have weak activity because they stabilize less active forms, sustain active states for a lesser fraction of the time or both, remains an open question. Here we describe the crystal structure of an α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate receptor (AMPAR) ligand binding domain (LBD) tetramer in complex with the partial agonist 5-fluorowillardiine (FW). We validate this structure, and others of different geometry, using engineered intersubunit bridges. We establish an inverse relation between the efficacy of an agonist and its promiscuity to drive the LBD layer into different conformations. These results suggest that partial agonists of the AMPAR are weak activators of the receptor because they stabilize multiple non-conducting conformations, indicating that agonism is a function of both the space and time domains.
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Dynamics of the Ligand Binding Domain Layer during AMPA Receptor Activation. Biophys J 2016; 110:896-911. [PMID: 26910426 DOI: 10.1016/j.bpj.2015.12.033] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 12/18/2015] [Accepted: 12/30/2015] [Indexed: 10/22/2022] Open
Abstract
Ionotropic glutamate receptors are postsynaptic tetrameric ligand-gated channels whose activity mediates fast excitatory transmission. Glutamate binding to clamshell-shaped ligand binding domains (LBDs) triggers opening of the integral ion channel, but how the four LBDs orchestrate receptor activation is unknown. Here, we present a high-resolution x-ray crystal structure displaying two tetrameric LBD arrangements fully bound to glutamate. Using a series of engineered metal ion trapping mutants, we showed that the more compact of the two assemblies corresponds to an arrangement populated during activation of full-length receptors. State-dependent cross-linking of the mutants identified zinc bridges between the canonical active LBD dimers that formed when the tetramer was either fully or partially bound by glutamate. These bridges also stabilized the resting state, consistent with the recently published full-length apo structure. Our results provide insight into the activation mechanism of glutamate receptors and the complex conformational space that the LBD layer can sample.
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Testing Hadronic Interactions at Ultrahigh Energies with Air Showers Measured by the Pierre Auger Observatory. PHYSICAL REVIEW LETTERS 2016; 117:192001. [PMID: 27858429 DOI: 10.1103/physrevlett.117.192001] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2016] [Indexed: 06/06/2023]
Abstract
Ultrahigh energy cosmic ray air showers probe particle physics at energies beyond the reach of accelerators. Here we introduce a new method to test hadronic interaction models without relying on the absolute energy calibration, and apply it to events with primary energy 6-16 EeV (E_{CM}=110-170 TeV), whose longitudinal development and lateral distribution were simultaneously measured by the Pierre Auger Observatory. The average hadronic shower is 1.33±0.16 (1.61±0.21) times larger than predicted using the leading LHC-tuned models EPOS-LHC (QGSJetII-04), with a corresponding excess of muons.
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Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy. PHYSICAL REVIEW LETTERS 2016; 116:241101. [PMID: 27367377 DOI: 10.1103/physrevlett.116.241101] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Indexed: 06/06/2023]
Abstract
We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8±0.7(stat)±6.7(syst) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principles calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.
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Functional Mechanisms of Desensitization in AMPA Receptors. Biophys J 2016. [DOI: 10.1016/j.bpj.2015.11.1119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Search for patterns by combining cosmic-ray energy and arrival directions at the Pierre Auger Observatory. THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS 2015; 75:269. [PMID: 26120280 PMCID: PMC4477714 DOI: 10.1140/epjc/s10052-015-3471-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 05/20/2015] [Indexed: 06/04/2023]
Abstract
Energy-dependent patterns in the arrival directions of cosmic rays are searched for using data of the Pierre Auger Observatory. We investigate local regions around the highest-energy cosmic rays with [Formula: see text] eV by analyzing cosmic rays with energies above [Formula: see text] eV arriving within an angular separation of approximately 15[Formula: see text]. We characterize the energy distributions inside these regions by two independent methods, one searching for angular dependence of energy-energy correlations and one searching for collimation of energy along the local system of principal axes of the energy distribution. No significant patterns are found with this analysis. The comparison of these measurements with astrophysical scenarios can therefore be used to obtain constraints on related model parameters such as strength of cosmic-ray deflection and density of point sources.
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Poly(vinylidene fluoride-trifluoroethylene)/NAY zeolite hybrid membranes as a drug release platform applied to ibuprofen release. Colloids Surf A Physicochem Eng Asp 2015. [DOI: 10.1016/j.colsurfa.2014.12.064] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Muons in air showers at the Pierre Auger Observatory: Mean number in highly inclined events. Int J Clin Exp Med 2015. [DOI: 10.1103/physrevd.91.032003] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Convergent regulation of neuronal differentiation and Erk and Akt kinases in human neural progenitor cells by lysophosphatidic acid, sphingosine 1-phosphate, and LIF: specific roles for the LPA1 receptor. ASN Neuro 2014; 6:6/6/1759091414558416. [PMID: 25424429 PMCID: PMC4357610 DOI: 10.1177/1759091414558416] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The bioactive lysophospholipids lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P) have diverse effects on the developing nervous system and neural progenitors, but the molecular basis for their pleiotropic effects is poorly understood. We previously defined LPA and S1P signaling in proliferating human neural progenitor (hNP) cells, and the current study investigates their role in neuronal differentiation of these cells. Differentiation in the presence of LPA or S1P significantly enhanced cell survival and decreased expression of neuronal markers. Further, the LPA receptor antagonist Ki16425 fully blocked the effects of LPA, and differentiation in the presence of Ki16425 dramatically enhanced neurite length. LPA and S1P robustly activated Erk, but surprisingly both strongly suppressed Akt activation. Ki16425 and pertussis toxin blocked LPA activation of Erk but not LPA inhibition of Akt, suggesting distinct receptor and G-protein subtypes mediate these effects. Finally, we explored cross talk between lysophospholipid signaling and the cytokine leukemia inhibitory factor (LIF). LPA/S1P effects on neuronal differentiation were amplified in the presence of LIF. Similarly, the ability of LPA/S1P to regulate Erk and Akt was impacted by the presence of LIF; LIF enhanced the inhibitory effect of LPA/S1P on Akt phosphorylation, while LIF blunted the activation of Erk by LPA/S1P. Taken together, our results suggest that LPA and S1P enhance survival and inhibit neuronal differentiation of hNP cells, and LPA1 is critical for the effect of LPA. The pleiotropic effects of LPA may reflect differences in receptor subtype expression or cross talk with LIF receptor signaling.
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Regulator of G protein signaling transcript expression in human neural progenitor differentiation: R7 subfamily regulation by DNA methylation. Neurosignals 2014; 22:43-51. [PMID: 24903911 DOI: 10.1159/000362128] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 03/10/2014] [Indexed: 11/19/2022] Open
Abstract
G protein-coupled receptors (GPCRs) and their ligands are critical regulators of neural progenitor differentiation, and GPCR signaling pathways are regulated by regulator of G protein signaling (RGS) proteins. RGS protein expression is dynamically regulated, and we have recently described the epigenetic regulation of RGS transcript expression. Given the potential of RGS proteins to regulate GPCR signaling and the established role of epigenetic regulation in progenitor differentiation, we explored the impact of epigenetic regulation of RGS transcripts during in vitro differentiation of human neural progenitors. Here, we demonstrate robust upregulation of the RGS transcripts RGS4, RGS5, RGS6, RGS7, and RGS11 during neuronal differentiation, while DNA methyltransferase (DNMT) and histone deacetylase enzyme expression is suppressed during differentiation. Transcripts encoding R7 subfamily RGS proteins and the R7-binding partners R7BP and R9AP showed the greatest upregulation. Further, we showed that direct pharmacological inhibition of DNMT activity enhances expression of RGS2, RGS4, RGS5, RGS6, RGS7, RGS8, RGS9L, RGS10, and RGS14 as well as R7BP and R9AP transcripts in progenitors, consistent with regulation by DNMTs. Our results reveal marked upregulation of RGS expression during neuronal differentiation and suggest that decreased expression of DNMT enzymes during differentiation contributes to upregulation.
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Dissecting the Activation of AMPA Receptors. Biophys J 2013. [DOI: 10.1016/j.bpj.2012.11.1525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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Measurement of the proton-air cross section at √s=57 TeV with the Pierre Auger Observatory. PHYSICAL REVIEW LETTERS 2012; 109:062002. [PMID: 23006259 DOI: 10.1103/physrevlett.109.062002] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Indexed: 06/01/2023]
Abstract
We report a measurement of the proton-air cross section for particle production at the center-of-mass energy per nucleon of 57 TeV. This is derived from the distribution of the depths of shower maxima observed with the Pierre Auger Observatory: systematic uncertainties are studied in detail. Analyzing the tail of the distribution of the shower maxima, a proton-air cross section of [505±22(stat)(-36)(+28)(syst)] mb is found.
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Measurement of the depth of maximum of extensive air showers above 10{18} eV. PHYSICAL REVIEW LETTERS 2010; 104:091101. [PMID: 20366976 DOI: 10.1103/physrevlett.104.091101] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2009] [Indexed: 05/29/2023]
Abstract
We describe the measurement of the depth of maximum, X{max}, of the longitudinal development of air showers induced by cosmic rays. Almost 4000 events above 10;{18} eV observed by the fluorescence detector of the Pierre Auger Observatory in coincidence with at least one surface detector station are selected for the analysis. The average shower maximum was found to evolve with energy at a rate of (106{-21}{+35}) g/cm{2}/decade below 10{18.24+/-0.05} eV, and (24+/-3) g/cm{2}/decade above this energy. The measured shower-to-shower fluctuations decrease from about 55 to 26 g/cm{2}. The interpretation of these results in terms of the cosmic ray mass composition is briefly discussed.
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A Retrospective Review of Association between Clinico-Pathologic Prognostic Factors and Disease Outcome in Node-Positive or High-Risk Node Negative Breast Cancer Patients Treated with Adjuvant Cyclophosphamide, Doxorubicin Followed by Paclitaxel: A Venezuelan Study. Cancer Res 2009. [DOI: 10.1158/0008-5472.sabcs-09-6056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Background: Breast cancer is a disease with a biologic and clinical heterogeneity explained by differences in the genetic composition, which translate into variability in estrogen receptor (ER), progesterone receptors (PR), Her2–Neu receptor (HER2) expression and permit to identify subgroups that show different prognoses and that also respond differently to treatment. The goal of this study was to determine disease-free survival (DFS) in relation to clinico-pathologic features and ER/PR/HER2 subgroups, in node-positive or high-risk breast cancer patients in a Venezuelan single institution. Methods: We reviewed data between May 1999 to July 2006, from our breast tumor registry with attention to clinical and pathologic prognostic factors. All patients were treated with either mastectomy or breast conserving surgery-with axillary node assessment for stage and adjuvant chemotherapy with doxorubicin 60mg/m2 and cyclophosphamide 600mg/m2 both IV day 1 x 4 cycles, followed by paclitaxel 175mg/m2 day 1 x 4 cycles every 3 weeks or every 2 weeks. All patient received radiation therapy and adjuvant hormonal therapy when indicated. Disease-free survival (DFS) was measured from the date of biopsy to the date of relapse. DFS was estimated using the univariate Kaplan-Meier method. Twelve clinico-pathologic factors that could influence relapse were selected and analyzed using the Cox Proportional Hazards Model. All analyses were carried out using Stata (version 6.0).Results: A total of 92 breast cancer patients all received adjuvant chemotherapy and radiotherapy, 79% of the patients received hormonal therapy with either Tamoxifen or an Aromatase Inhibitor according to their menopausal status. The median follow-up is 55.42 months (range 9.5-110 months). Median age was 50 years (27-70). Local and distant failures were 3% and 11% respectively. For the overall population, the probability of DFS at 2, 5 and 9 years was respectively 93%, 83% and 83%. The results of univariate analysis showed that the mayor significant prognostic factor for influencing relapse was Estrogen receptor (HR:0.29) (p=0.06). Univariate survival analyses comparing grade of differentiation, stage of disease and number of metastasis in axillary lymph nodes with respect to Disease-free survival were performed and showed no significant difference. Patients with triple negative tumors showed an increased risk of relapse with a significant decrease in 9-year disease-free survival 38.1% (p<0.001) and patients with ER+/PR+/HER2- had the best DFS 90% (p<0.001). Conclusions: Estrogen receptor expression was the most significant biologic prognostic factors for relapse in this population. Triple negative tumors were associated with worse DFS. Different DFS in ER/PR/HER2 subgroups clearly illustrates the heterogeneity of this disease and support the importance of tailored therapy in this era.
Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6056.
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[The TRPV1 channel as a target for the treatment of pain]. Rev Neurol 2009; 48:357-364. [PMID: 19319817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
INTRODUCTION Pain results from the processing of a large number of signals produced at different levels of the central and peripheral nervous system, which are generated in response to stimuli from the environment or from the organism itself. One of the strategies for generating new analgesics consists in studying the molecular bases that underlie the detection of painful stimuli, that is to say, the receptors. One receptor that plays a very important role in sensory and pain physiology is TRPV1, which is responsible for detecting mechanical, chemical and thermal stimuli. AIMS. The aim of this study is to discuss the structural and functional aspects of the TRPV1 channel, as well as its participation in certain pathological processes and the possible perspectives for clinical research. DEVELOPMENT TRPV1 activation in sensory neurons generates signals that reach the central nervous system, where they are interpreted as pain, as well as triggering the peripheral release of pro-inflammatory substances that make other neurons sensitive to subsequent stimuli. TRPV1 is a receptor that is structurally similar to other voltage-dependent ion channels, with the capacity to detect and integrate several different stimuli from the environment, such as dangerously high temperatures or irritants. Furthermore, the activity of this channel is linked to several signalling chains related with inflammatory processes. CONCLUSIONS The central role of TRPV1 in the physiology of pain will surely encourage the development of drugs aimed at this receptor which can be used in the treatment of several types of pain.
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Observation of the suppression of the flux of cosmic rays above 4 x 10 (19) eV. PHYSICAL REVIEW LETTERS 2008; 101:061101. [PMID: 18764444 DOI: 10.1103/physrevlett.101.061101] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2008] [Indexed: 05/26/2023]
Abstract
The energy spectrum of cosmic rays above 2.5 x 10;{18} eV, derived from 20,000 events recorded at the Pierre Auger Observatory, is described. The spectral index gamma of the particle flux, J proportional, variantE;{-gamma}, at energies between 4 x 10;{18} eV and 4 x 10;{19} eV is 2.69+/-0.02(stat)+/-0.06(syst), steepening to 4.2+/-0.4(stat)+/-0.06(syst) at higher energies. The hypothesis of a single power law is rejected with a significance greater than 6 standard deviations. The data are consistent with the prediction by Greisen and by Zatsepin and Kuz'min.
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Upper limit on the diffuse flux of ultrahigh energy tau neutrinos from the Pierre Auger Observatory. PHYSICAL REVIEW LETTERS 2008; 100:211101. [PMID: 18518595 DOI: 10.1103/physrevlett.100.211101] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2007] [Indexed: 05/26/2023]
Abstract
The surface detector array of the Pierre Auger Observatory is sensitive to Earth-skimming tau neutrinos that interact in Earth's crust. Tau leptons from nu(tau) charged-current interactions can emerge and decay in the atmosphere to produce a nearly horizontal shower with a significant electromagnetic component. The data collected between 1 January 2004 and 31 August 2007 are used to place an upper limit on the diffuse flux of nu(tau) at EeV energies. Assuming an E(nu)(-2) differential energy spectrum the limit set at 90% C.L. is E(nu)(2)dN(nu)(tau)/dE(nu)<1.3 x 10(-7) GeV cm(-2) s(-1) sr(-1) in the energy range 2 x 10(17) eV< E(nu)< 2 x 10(19) eV.
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CgNa, a type I toxin from the giant Caribbean sea anemone Condylactis gigantea shows structural similarities to both type I and II toxins, as well as distinctive structural and functional properties(1). Biochem J 2007; 406:67-76. [PMID: 17506725 PMCID: PMC1948996 DOI: 10.1042/bj20070130] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
CgNa (Condylactis gigantea neurotoxin) is a 47-amino-acid- residue toxin from the giant Caribbean sea anemone Condylactis gigantea. The structure of CgNa, which was solved by 1H-NMR spectroscopy, is somewhat atypical and displays significant homology with both type I and II anemone toxins. CgNa also displays a considerable number of exceptions to the canonical structural elements that are thought to be essential for the activity of this group of toxins. Furthermore, unique residues in CgNa define a characteristic structure with strong negatively charged surface patches. These patches disrupt a surface-exposed cluster of hydrophobic residues present in all anemone-derived toxins described to date. A thorough characterization by patch-clamp analysis using rat DRG (dorsal root ganglion) neurons indicated that CgNa preferentially binds to TTX-S (tetrodotoxin-sensitive) voltage-gated sodium channels in the resting state. This association increased the inactivation time constant and the rate of recovery from inactivation, inducing a significant shift in the steady state of inactivation curve to the left. The specific structural features of CgNa may explain its weaker inhibitory capacity when compared with the other type I and II anemone toxins.
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Daughter, you broke my heart: accidental thrombosis at a muscular bridge. Tex Heart Inst J 2006; 33:380-2. [PMID: 17041702 PMCID: PMC1592268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
We report the case of a 59-year-old trained runner, who sustained an acute myocardial infarction, with residual effort angina, following extreme exertion while experiencing severe anxiety. Coronary angiography revealed that this patient had a myocardial bridge at the mid-left anterior descending artery, and an occlusive clot had developed at the proximal end of the muscular bridge. We discuss the possible relationships between the various circumstances of this sudden event. We argue that, under exceptional conditions, myocardial bridges can lead to myocardial infarction by clot formation.
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Abstract
BACKGROUND The cadherins are homotypic adhesion proteins that are important in cell sorting during organogenesis. Classic cadherins include several different types that show tissue specific expression. Specific tissue expression of cadherins often is preserved in neoplastic transformation, and cadherin phenotype can be used to differentiate morphologically similar but histogenetically distinct tumors. METHODS The authors examined by using immunohistochemistry in paraffin sections the expression of E- (epithelial) and P- (placental) cadherin in 39 patients with glandular tumors of the cervix, including invasive adenocarcinoma, villoglandular adenocarcinoma, adenocarcinoma in situ (AIS), and adenoma malignum. RESULTS In all cases, E-cadherin was expressed in both normal and malignant glands without appreciable differences. P-cadherin, normally confined to basal epithelial cells and not observed in benign glands, was aberrantly expressed in neoplastic glands in 27 cases, including 96%(23 of 24 cases) of invasive cancers, 40% (2 of 5) of villoglandular carcinomas, 25% (2 of 8) of AIS, and 0% (0 of 2) of adenoma malignum. CONCLUSIONS The authors' results show that E-cadherin is uniformly expressed in glandular tumors of the cervix with no evidence of decreased expression in these tumors. In addition, P-cadherin is aberrantly expressed in most adenocarcinomas and appears to be preferentially expressed in invasive rather than in situ lesions. Thus, aberrant expression of P-cadherin may be a useful marker of invasive or aggressive clinical behavior in glandular lesions of the cervix.
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Abstract
CONTEXT Cadherins are cell-cell adhesion proteins that act as tumor suppressor genes and have a critical role in cell sorting and tissue formation during organogenesis. The pattern of cadherin expression constitutes a useful diagnostic and prognostic tool in the evaluation of tumors and for determining the histogenesis of tumor cells. We have previously characterized the cell types of several tumors based on the expression of individual cadherins. OBJECTIVE To investigate the expression of cadherins in Merkel cell carcinomas. DESIGN Paraffin immunohistochemical analysis of the 3 best-studied cadherins was performed on 35 cases of Merkel cell carcinoma. RESULTS E-cadherin was expressed in 34 (97%) of 35 Merkel cell carcinomas examined, N-cadherin was expressed in 22 (63%) of 35 cases, and P-cadherin was expressed in 15 (43%) of 35 cases. This frequency of cadherin expression was similar to a group of small cell and neuroendocrine tumors from other primary sites. Interestingly, the localization of E-cadherin expression was unique in Merkel cell carcinomas compared with other primary neuroendocrine tumors. Merkel cell carcinomas showed marked preference for nuclear versus membrane localization, whereas small cell tumors from other sites showed fewer cases of nuclear E-cadherin expression. The nuclear localization of E-cadherin did not correlate with cadherin-associated protein beta-catenin nuclear expression. CONCLUSIONS Our findings show that E-cadherin is the most frequently expressed cadherin in Merkel cell carcinoma, followed in frequency by N-cadherin then P-cadherin. The pattern of nuclear E-cadherin expression is more frequent for Merkel cell carcinoma than small cell tumors of other primary sites. These observations suggest that E-cadherin expression and function are altered in Merkel cell carcinoma, and this finding has potential use in the differential diagnosis of these tumors.
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Abstract
The International Society of Gynecological Pathologists was founded in 1976 to facilitate an exchange of knowledge about gynecological disease throughout the world. The Society moved quickly to schedule companion meetings with established international and regional pathology and gynecology societies, including the International Academy of Pathology, its United States-Canadian Division, and the International Federation of Gynecology and Obstetrics, and to sponsor smaller meetings within individual countries. In 1981 the Society founded this journal, and in 1983, at the invitation of the World Health Organization, it assumed the responsibility of revising the WHO classifications of tumors of the female genital tract. The foundation of the Society appears to have been solid in view of its present robust health.
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