1,399 research outputs found

    Rigid rotators and diatomic molecules via Tsallis statistics

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    We obtain an analytic expression for the specific heat of a system of N rigid rotators exactly in the high temperature limit, and via a pertubative approach in the low temperature limit. We then evaluate the specific heat of a diatomic gas with both translational and rotational degrees of freedom, and conclude that there is a mixing between the translational and rotational degrees of freedom in nonextensive statistics.Comment: 12 page

    Hard X-ray lags in active galactic nuclei: Testing the distant reverberation hypothesis with NGC 6814

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    We present an X-ray spectral and temporal analysis of the variable active galaxy NGC 6814, observed with Suzaku during November 2011. Remarkably, the X-ray spectrum shows no evidence for the soft excess commonly observed amongst other active galaxies, despite its relatively low level of obscuration, and is dominated across the whole Suzaku bandpass by the intrinsic powerlaw-like continuum. Despite this, we clearly detect the presence of a low frequency hard lag of ~1600s between the 0.5-2.0 and 2.0-5.0 keV energy bands at greater than 6-sigma significance, similar to those reported in the literature for a variety of other AGN. At these energies, any additional emission from e.g. a very weak, undetected soft excess, or from distant reflection must contribute less than 3% of the observed countrates (at 90% confidence). Given the lack of any significant continuum emission component other than the powerlaw, we can rule out models that invoke distant reprocessing for the observed lag behavior, which must instead be associated with this continuum emission. These results are fully consistent with a propagating fluctuation origin for the low frequency hard lags, and with the interpretation of the high frequency soft lags - a common feature seen in the highest quality AGN data with strong soft excesses - as reverberation from the inner accretion disk

    A selective p53 activator and anticancer agent to improve colorectal cancer therapy

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    Impairment of the p53 pathway is a critical event in cancer. Therefore, reestablishing p53 activity has become one of the most appealing anticancer therapeutic strategies. Here, we disclose the p53-activating anticancer drug (3S)-6,7-bis(hydroxymethyl)-5-methyl-3-phenyl-1H,3H-pyrrolo[1,2-c]thiazole (MANIO). MANIO demonstrates a notable selectivity to the p53 pathway, activating wild-type (WT)p53 and restoring WT-like function to mutant (mut)p53 in human cancer cells. MANIO directly binds to the WT/mutp53 DNA-binding domain, enhancing the protein thermal stability, DNA-binding ability, and transcriptional activity. The high efficacy of MANIO as an anticancer agent toward cancers harboring WT/mutp53 is further demonstrated in patient-derived cells and xenograft mouse models of colorectal cancer (CRC), with no signs of undesirable side effects. MANIO synergizes with conventional chemotherapeutic drugs, and in vitro and in vivo studies predict its adequate drug-likeness and pharmacokinetic properties for a clinical candidate. As a single agent or in combination, MANIO will advance anticancer-targeted therapy, particularly benefiting CRC patients harboring distinct p53 status.We thank PT national funds (FCT/MCTES , Fundação para a Ciência e a Tecnologia , and Ministério da Ciência, Tecnologia e Ensino Superior ) through grants UIDB/50006/2020 , UID/BIO/04469/2019 , UIDB/04539/2020 , and UIDP/04539/2020 ( CIBB ); BioTecNorte operation ( NORTE-01-0145-FEDER-000004 ) and Porto Neurosciences and Neurologic Disease Research Initiative at I3S ( Norte-01-0145-FEDER-000008 ) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte ; Masaryk University ( Project MUNI/A/1127/2019 ) and Ministry of Education, Youth and Sports of the Czech Republic (project nos. LQ1605 and LM2018125 ); FCT financial support through the fellowships SFRH/BD/119144/2016 (H.R.) and SFRH/BD/117949/2016 (L.R.); Fondazione AIRC ( IG#18985 , A.I.); and the Programa Operacional Potencial Humano (POCH), specifically the BiotechHealth Programme (Doctoral Programme on Cellular and Molecular Biotechnology Applied to Health Sciences , PD/00016/2012 ). We thank Dario Rizzotto for assistance in preparing the libraries for RNA sequencing. Funding: This work was supported by PT National Funds (FCT/MCTES, Fundação para a Ciência e Tecnologia , and Ministério da Ciência, Tecnologia e Ensino Superior ) via the projects UIDB/50006/2020 ( LAQV/REQUIMTE ), UIDB/00313/2020 , and UIDP/00313/2020 , co-funded by COMPETE2020-UE

    Genetic diversity of Brazilian isolates of feline immunodeficiency virus

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    We isolated Feline immunodeficiency virus (FIV) from three adult domestic cats, originating from two open shelters in Brazil. Viruses were isolated from PBMC following co-cultivation with the feline T-lymphoblastoid cell line MYA-1. All amplified env gene products were cloned directly into pGL8MYA. The nucleic acid sequences of seven clones were determined and then compared with those of previously described isolates. The sequences of all of the Brazilian virus clones were distinct and phylogenetic analysis revealed that all belong to subtype B. Three variants isolated from one cat and two variants were isolated from each of the two other cats, indicating that intrahost diversity has the potential to pose problems for the treatment and diagnosis of FIV infection

    How consistent are the transcriptome changes associated with cold acclimation in two species of the Drosophila virilis group?

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    This work was financially support by a Marie Curie Initial Training Network grant, “Understanding the evolutionary origin of biological diversity” (ITN-2008–213780 SPECIATION), grants from the Academy of Finland to A.H. (project 132619) and M.K. (projects 268214 and 272927), a grant from NERC, UK to M.G.R. (grant NE/J020818/1), and NERC, UK PhD studentship to D.J.P. (NE/I528634/1).For many organisms the ability to cold acclimate with the onset of seasonal cold has major implications for their fitness. In insects, where this ability is widespread, the physiological changes associated with increased cold tolerance have been well studied. Despite this, little work has been done to trace changes in gene expression during cold acclimation that lead to an increase in cold tolerance. We used an RNA-Seq approach to investigate this in two species of the Drosophila virilis group. We found that the majority of genes that are differentially expressed during cold acclimation differ between the two species. Despite this, the biological processes associated with the differentially expressed genes were broadly similar in the two species. These included: metabolism, cell membrane composition, and circadian rhythms, which are largely consistent with previous work on cold acclimation/cold tolerance. In addition, we also found evidence of the involvement of the rhodopsin pathway in cold acclimation, a pathway that has been recently linked to thermotaxis. Interestingly, we found no evidence of differential expression of stress genes implying that long-term cold acclimation and short-term stress response may have a different physiological basis.PostprintPeer reviewe

    Characterisation of mechanical and thermal properties in flax fabric reinforced geopolymer composites

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    This paper presents the mechanical and thermal properties of flax fabric reinforced fly ash based geopolymer composites. Geopolymer composites reinforced with 2.4, 3.0 and 4.1 wt% woven flax fabric in various layers were fabricated using a hand lay-up technique and tested for mechanical properties such as flexural strength, flexural modulus, compressive strength, hardness, and fracture toughness. All mechanical properties were improved by increasing the flax fibre contents, and showed superior mechanical properties over a pure geopolymer matrix. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) studies were carried out to evaluate the composition and fracture surfaces of geopolymer and geopolymer/flax composites. The thermal behaviour of composites was studied by thermogravimetric analysis (TGA) and the results showed significant degradation of flax fibres at 300 °C
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