157 research outputs found
The origin and prevention of pandemics.
Despite the fact that most emerging diseases stem from the transmission of pathogenic agents from animals to humans, the factors that mediate this process are still ill defined. What is known, however, is that the interface between humans and animals is of paramount importance in the process. This review will discuss the importance of the human-animal interface to the disease emergence process. We also provide an overview of factors that are believed to contribute to the origin and global spread of emerging infectious diseases and offer suggestions that may serve as future prevention strategies, such as social mobilization, public health education, behavioral change, and communication strategies. Because there exists no comprehensive global surveillance system to monitor zoonotic disease emergence, the intervention measures discussed herein may prove effective temporary alternatives
Comparisons of substitution, insertion and deletion probes for resequencing and mutational analysis using oligonucleotide microarrays
Although oligonucleotide probes complementary to single nucleotide substitutions are commonly used in microarray-based screens for genetic variation, little is known about the hybridization properties of probes complementary to small insertions and deletions. It is necessary to define the hybridization properties of these latter probes in order to improve the specificity and sensitivity of oligonucleotide microarray-based mutational analysis of disease-related genes. Here, we compare and contrast the hybridization properties of oligonucleotide microarrays consisting of 25mer probes complementary to all possible single nucleotide substitutions and insertions, and one and two base deletions in the 9168 bp coding region of the ATM (ataxia telangiectasia mutated) gene. Over 68 different dye-labeled single-stranded nucleic acid targets representing all ATM coding exons were applied to these microarrays. We assess hybridization specificity by comparing the relative hybridization signals from probes perfectly matched to ATM sequences to those containing mismatches. Probes complementary to two base substitutions displayed the highest average specificity followed by those complementary to single base substitutions, single base deletions and single base insertions. In all the cases, hybridization specificity was strongly influenced by sequence context and possible intra- and intermolecular probe and/or target structure. Furthermore, single nucleotide substitution probes displayed the most consistent hybridization specificity data followed by single base deletions, two base deletions and single nucleotide insertions. Overall, these studies provide valuable empirical data that can be used to more accurately model the hybridization properties of insertion and deletion probes and improve the design and interpretation of oligonucleotide microarray-based resequencing and mutational analysis
Future Contingents and the Logic of Temporal Omniscience
At least since Aristotleâs famous 'sea-battle' passages in On Interpretation 9, some substantial minority of philosophers has been attracted to the doctrine of the open future--the doctrine that future contingent statements are not true. But, prima facie, such views seem inconsistent with the following intuition: if something has happened, then (looking back) it was the case that it would happen. How can it be that, looking forwards, it isnât true that there will be a sea battle, while also being true that, looking backwards, it was the case that there would be a sea battle? This tension forms, in large part, what might be called the problem of future contingents. A dominant trend in temporal logic and semantic theorizing about future contingents seeks to validate both intuitions. Theorists in this tradition--including some interpretations of Aristotle, but paradigmatically, Thomason (1970), as well as more recent developments in Belnap, et. al (2001) and MacFarlane (2003, 2014)--have argued that the apparent tension between the intuitions is in fact merely apparent. In short, such theorists seek to maintain both of the following two theses: (i) the open future: Future contingents are not true, and (ii) retro-closure: From the fact that something is true, it follows that it was the case that it would be true. It is well-known that reflection on the problem of future contingents has in many ways been inspired by importantly parallel issues regarding divine foreknowledge and indeterminism. In this paper, we take up this perspective, and ask what accepting both the open future and retro-closure predicts about omniscience. When we theorize about a perfect knower, we are theorizing about what an ideal agent ought to believe. Our contention is that there isnât an acceptable view of ideally rational belief given the assumptions of the open future and retro-closure, and thus this casts doubt on the conjunction of those assumptions
Synthesis and biologic properties of hydrophilic sapphyrins, a new class of tumor-selective inhibitors of gene expression
BACKGROUND: Sapphyrin analogues and related porphyrin-like species have attracted attention as anticancer agents due to their selective localization in various cancers, including hematologic malignancies, relative to surrounding tissues. Sapphyrins are electron affinic compounds that generate high yields of singlet oxygen formation. Although initially explored in the context of photodynamic therapy, sapphyrins have intrinsic anticancer activity that is independent of their photosensitizing properties. However, the mechanisms for their anticancer activity have not been fully elucidated. RESULTS: We have prepared a series of hydrophilic sapphyrins and evaluated their effect on proliferation, uptake, and cell death in adherent human lung (A549) and prostate (PC3) cancer cell lines and in an A549 xenograft tumor model. PCI-2050, the sapphyrin derivative with the highest in vitro growth inhibitory activity, significantly lowered 5-bromo-2'-deoxyuridine incorporation in S-phase A549 cells by 60% within eight hours and increased levels of reactive oxygen species within four hours. The growth inhibition pattern of PCI-2050 in the National Cancer Institute 60 cell line screen correlated most closely using the COMPARE algorithm with known transcriptional or translational inhibitors. Gene expression analyses conducted on A549 plateau phase cultures treated with PCI-2050 uncovered wide-spread decreases in mRNA levels, which especially affected short-lived transcripts. Intriguingly, PCI-2050 increased the levels of transcripts involved in RNA processing and trafficking, transcriptional regulation, and chromatin remodeling. We propose that these changes reflect the activation of cellular processes aimed at countering the observed wide-spread reductions in transcript levels. In our A549 xenograft model, the two lead compounds, PCI-2050 and PCI-2022, showed similar tumor distributions despite differences in plasma and kidney level profiles. This provides a possible explanation for the better tolerance of PCI-2022 relative to PCI-2050. CONCLUSION: Hydrophilic sapphyrins were found to display promise as novel agents that localize to tumors, generate oxidative stress, and inhibit gene expression
A Comprehensive X-ray Report on AT2019wey
The Galactic low-mass X-ray binary AT2019wey (ATLAS19bcxp, SRGA J043520.9+552226, SRGE J043523.3+552234, ZTF19acwrvzk) was discovered as a new optical transient in Dec 2019, and independently as an X-ray transient in Mar 2020. In this paper, we present comprehensive NICER, NuSTAR, Chandra, Swift, and MAXI observations of AT2019wey from ~1 year prior to the discovery to the end of September 2020. AT2019wey appeared as a ~1 mCrab source and stayed at this flux density for several months, displaying a hard X-ray spectrum that can be modeled as a power-law with photon index Gamma~1.8. In June 2020 it started to brighten, and reached ~20 mCrab in ~2 months. The inclination of this system can be constrained to iâŸ30 deg by modeling the reflection spectrum. Starting from late-August (~59082 MJD), AT2019wey entered into the hard-intermediate state (HIMS), and underwent a few week-long timescale outbursts, where the brightening in soft X-rays is correlated with the enhancement of a thermal component. Low-frequency quasi-periodic oscillation (QPO) was observed in the HIMS. We detect no pulsation and in timing analysis of the NICER and NuSTAR data. The X-ray states and power spectra of AT2019wey are discussed against the landscape of low-mass X-ray binaries
LSST: from Science Drivers to Reference Design and Anticipated Data Products
(Abridged) We describe here the most ambitious survey currently planned in
the optical, the Large Synoptic Survey Telescope (LSST). A vast array of
science will be enabled by a single wide-deep-fast sky survey, and LSST will
have unique survey capability in the faint time domain. The LSST design is
driven by four main science themes: probing dark energy and dark matter, taking
an inventory of the Solar System, exploring the transient optical sky, and
mapping the Milky Way. LSST will be a wide-field ground-based system sited at
Cerro Pach\'{o}n in northern Chile. The telescope will have an 8.4 m (6.5 m
effective) primary mirror, a 9.6 deg field of view, and a 3.2 Gigapixel
camera. The standard observing sequence will consist of pairs of 15-second
exposures in a given field, with two such visits in each pointing in a given
night. With these repeats, the LSST system is capable of imaging about 10,000
square degrees of sky in a single filter in three nights. The typical 5
point-source depth in a single visit in will be (AB). The
project is in the construction phase and will begin regular survey operations
by 2022. The survey area will be contained within 30,000 deg with
, and will be imaged multiple times in six bands, ,
covering the wavelength range 320--1050 nm. About 90\% of the observing time
will be devoted to a deep-wide-fast survey mode which will uniformly observe a
18,000 deg region about 800 times (summed over all six bands) during the
anticipated 10 years of operations, and yield a coadded map to . The
remaining 10\% of the observing time will be allocated to projects such as a
Very Deep and Fast time domain survey. The goal is to make LSST data products,
including a relational database of about 32 trillion observations of 40 billion
objects, available to the public and scientists around the world.Comment: 57 pages, 32 color figures, version with high-resolution figures
available from https://www.lsst.org/overvie
Screening and association testing of common coding variation in steroid hormone receptor co-activator and co-repressor genes in relation to breast cancer risk: the Multiethnic Cohort
<p>Abstract</p> <p>Background</p> <p>Only a limited number of studies have performed comprehensive investigations of coding variation in relation to breast cancer risk. Given the established role of estrogens in breast cancer, we hypothesized that coding variation in steroid receptor coactivator and corepressor genes may alter inter-individual response to estrogen and serve as markers of breast cancer risk.</p> <p>Methods</p> <p>We sequenced the coding exons of 17 genes (<it>EP300, CCND1, NME1, NCOA1, NCOA2, NCOA3, SMARCA4, SMARCA2, CARM1, FOXA1, MPG, NCOR1, NCOR2, CALCOCO1, PRMT1, PPARBP </it>and <it>CREBBP</it>) suggested to influence transcriptional activation by steroid hormone receptors in a multiethnic panel of women with advanced breast cancer (n = 95): African Americans, Latinos, Japanese, Native Hawaiians and European Americans. Association testing of validated coding variants was conducted in a breast cancer case-control study (1,612 invasive cases and 1,961 controls) nested in the Multiethnic Cohort. We used logistic regression to estimate odds ratios for allelic effects in ethnic-pooled analyses as well as in subgroups defined by disease stage and steroid hormone receptor status. We also investigated effect modification by established breast cancer risk factors that are associated with steroid hormone exposure.</p> <p>Results</p> <p>We identified 45 coding variants with frequencies â„ 1% in any one ethnic group (43 non-synonymous variants). We observed nominally significant positive associations with two coding variants in ethnic-pooled analyses (<it>NCOR2</it>: His52Arg, OR = 1.79; 95% CI, 1.05â3.05; <it>CALCOCO1</it>: Arg12His, OR = 2.29; 95% CI, 1.00â5.26). A small number of variants were associated with risk in disease subgroup analyses and we observed no strong evidence of effect modification by breast cancer risk factors. Based on the large number of statistical tests conducted in this study, the nominally significant associations that we observed may be due to chance, and will need to be confirmed in other studies.</p> <p>Conclusion</p> <p>Our findings suggest that common coding variation in these candidate genes do not make a substantial contribution to breast cancer risk in the general population. Cataloging and testing of coding variants in coactivator and corepressor genes should continue and may serve as a valuable resource for investigations of other hormone-related phenotypes, such as inter-individual response to hormonal therapies used for cancer treatment and prevention.</p
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