125 research outputs found

    A comparison of quasar emission reconstruction techniques for z ā‰„ 5.0 Lymanā€‰Ī± and Lymanā€‰Ī² transmission

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    Reconstruction techniques for intrinsic quasar continua are crucial for the precision study of Lyman-Ī±\alpha (Ly-Ī±\alpha) and Lyman-Ī²\beta (Ly-Ī²\beta) transmission at z>5.0z>5.0, where the Ī»5.7\lambda5.7 with IR X-Shooter spectroscopy, obtaining well-characterised measurements for the mean flux transmission at 4.7<z<6.34.7<z<6.3. Our results demonstrate the importance of testing and, when relevant, training, continuum reconstruction techniques in a systematic way

    Examining the Decline in the C~IV Content of the Universe over 4.3ā€‰ā‰²ā€‰zā€‰ā€‰ā‰²ā€‰6.3 using the E-XQR-30 Sample

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    Intervening Cā€‰iv absorbers are key tracers of metal-enriched gas in galaxy haloes over cosmic time. Previous studies suggest that the Cā€‰iv cosmic mass density (ā [Math Processing Error]ā ) decreases slowly over 1.5 [Math Processing Error] 5 before declining rapidly at z ā‰³ 5, but the cause of this downturn is poorly understood. We characterize the [Math Processing Error] evolution over 4.3 ā‰² z ā‰² 6.3 using 260 absorbers found in 42 XSHOOTER spectra of z āˆ¼ 6 quasars, of which 30 come from the ESO Large Program XQR-30. The large sample enables us to robustly constrain the rate and timing of the downturn. We find that [Math Processing Error] decreases by a factor of 4.8 Ā± 2.0 over the āˆ¼300ā€‰Myr interval between z āˆ¼ 4.7 and āˆ¼5.8. The slope of the column density (logā€‰N) distribution function does not change, suggesting that Cā€‰iv absorption is suppressed approximately uniformly across 13.2 ā‰¤ logā€‰N/cmāˆ’2 &lt; 15.0. Assuming that the carbon content of galaxy haloes evolves as the integral of the cosmic star formation rate density (with some delay due to stellar lifetimes and outflow travel times), we show that chemical evolution alone could plausibly explain the fast decline in [Math Processing Error] over 4.3 ā‰² z ā‰² 6.3. However, the Cā€‰iv/C ii ratio decreases at the highest redshifts, so the accelerated decline in [Math Processing Error] at z ā‰³ 5 may be more naturally explained by rapid changes in the gas ionization state driven by evolution of the UV background towards the end of hydrogen reionization

    Attainment rate as a surrogate indicator of the intervertebral neutral zone length in lateral bending: An in vitro proof of concept study

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    Background Lumbar segmental instability is often considered to be a cause of chronic low back pain. However, defining its measurement has been largely limited to laboratory studies. These have characterised segmental stability as the intrinsic resistance of spine specimens to initial bending moments by quantifying the dynamic neutral zone. However these measurements have been impossible to obtain in vivo without invasive procedures, preventing the assessment of intervertebral stability in patients. Quantitative fluoroscopy (QF), measures the initial velocity of the attainment of intervertebral rotational motion in patients, which may to some extent be representative of the dynamic neutral zone. This study sought to explore the possible relationship between the dynamic neutral zone and intervertebral rotational attainment rate as measured with (QF) in an in vitro preparation. The purpose was to find out if further work into this concept is worth pursuing. Method This study used passive recumbent QF in a multi-segmental porcine model. This assessed the intrinsic intervertebral responses to a minimal coronal plane bending moment as measured with a digital force guage. Bending moments about each intervertebral joint were calculated and correlated with the rate at which global motion was attained at each intervertebral segment in the first 10Ā° of global motion where the intervertebral joint was rotating. Results Unlike previous studies of single segment specimens, a neutral zone was found to exist during lateral bending. The initial attainment rates for left and right lateral flexion were comparable to previously published in vivo values for healthy controls. Substantial and highly significant levels of correlation between initial attainment rate and neutral zone were found for left (Rhoā€‰=ā€‰0.75, Pā€‰=ā€‰0.0002) and combined left-right bending (Rhoā€‰=ā€‰0.72, Pā€‰=ā€‰0.0001) and moderate ones for right alone (Rhoā€‰=ā€‰0.55, Pā€‰=ā€‰0.0012). Conclusions This study found good correlation between the initial intervertebral attainment rate and the dynamic neutral zone, thereby opening the possibility to detect segmental instability from clinical studies. However the results must be treated with caution. Further studies with multiple specimens and adding sagittal plane motion are warranted

    Colorectal Cancer Prognosis Following Obesity Surgery in a Population-Based Cohort Study

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    Background: Obesity surgery involves mechanical and physiological changes of the gastrointestinal tract that might promote colorectal cancer progression. Thus, we hypothesised that obesity surgery is associated with poorer prognosis in patients with colorectal cancer. Methods: This nationwide population-based cohort study included all patients with an obesity diagnosis who subsequently developed colorectal cancer in Sweden from 1980 to 2012. The exposure was obesity surgery, and the main and secondary outcomes were disease-specific mortality and all-cause mortality, respectively. Cox proportional hazard survival models were used to calculate hazard ratios (HRs) with 95% confidence intervals (CIs), adjusted for sex, age, calendar year and education level. Results: The exposed and unexposed cohort included 131 obesity surgery and 1332 non-obesity surgery patients with colorectal cancer. There was a statistically significant increased rate of colorectal cancer deaths following obesity surgery (disease-specific HR 1.50, 95% CI 1.00ā€“2.19). When analysed separately, the mortality rate was more than threefold increased in rectal cancer patients with prior obesity surgery (disease-specific HR 3.70, 95% CI 2.00ā€“6.90), while no increased mortality rate was found in colon cancer patients (disease-specific HR 1.10, 85% CI 0.67ā€“1.70). Conclusion: This population-based study among obese individuals found a poorer prognosis in colorectal cancer following obesity surgery, which was primarily driven by the higher mortality rate in rectal cancer

    Metabolic compartmentalization in the human cortex and hippocampus: evidence for a cell- and region-specific localization of lactate dehydrogenase 5 and pyruvate dehydrogenase

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    BACKGROUND: For a long time now, glucose has been thought to be the main, if not the sole substrate for brain energy metabolism. Recent data nevertheless suggest that other molecules, such as monocarboxylates (lactate and pyruvate mainly) could be suitable substrates. Although monocarboxylates poorly cross the blood brain barrier (BBB), such substrates could replace glucose if produced locally.The two key enzymatiques systems required for the production of these monocarboxylates are lactate dehydrogenase (LDH; EC1.1.1.27) that catalyses the interconversion of lactate and pyruvate and the pyruvate dehydrogenase complex that irreversibly funnels pyruvate towards the mitochondrial TCA and oxydative phosphorylation. RESULTS: In this article, we show, with monoclonal antibodies applied to post-mortem human brain tissues, that the typically glycolytic isoenzyme of lactate dehydrogenase (LDH-5; also called LDHA or LDHM) is selectively present in astrocytes, and not in neurons, whereas pyruvate dehydrogenase (PDH) is mainly detected in neurons and barely in astrocytes. At the regional level, the distribution of the LDH-5 immunoreactive astrocytes is laminar and corresponds to regions of maximal 2-deoxyglucose uptake in the occipital cortex and hippocampus. In hippocampus, we observed that the distribution of the oxidative enzyme PDH was enriched in the neurons of the stratum pyramidale and stratum granulosum of CA1 through CA4, whereas the glycolytic enzyme LDH-5 was enriched in astrocytes of the stratum moleculare, the alveus and the white matter, revealing not only cellular, but also regional, selective distributions. The fact that LDH-5 immunoreactivity was high in astrocytes and occurred in regions where the highest uptake of 2-deoxyglucose was observed suggests that glucose uptake followed by lactate production may principally occur in these regions. CONCLUSION: These observations reveal a metabolic segregation, not only at the cellular but also at the regional level, that support the notion of metabolic compartmentalization between astrocytes and neurons, whereby lactate produced by astrocytes could be oxidized by neurons

    Phylogenetic organization of bacterial activity.

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    Phylogeny is an ecologically meaningful way to classify plants and animals, as closely related taxa frequently have similar ecological characteristics, functional traits and effects on ecosystem processes. For bacteria, however, phylogeny has been argued to be an unreliable indicator of an organism\u27s ecology owing to evolutionary processes more common to microbes such as gene loss and lateral gene transfer, as well as convergent evolution. Here we use advanced stable isotope probing with (13)C and (18)O to show that evolutionary history has ecological significance for in situ bacterial activity. Phylogenetic organization in the activity of bacteria sets the stage for characterizing the functional attributes of bacterial taxonomic groups. Connecting identity with function in this way will allow scientists to begin building a mechanistic understanding of how bacterial community composition regulates critical ecosystem functions.The ISME Journal advance online publication, 4 March 2016; doi:10.1038/ismej.2016.28

    XQR-30: The ultimate XSHOOTER quasar sample at the reionization epoch

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    The final phase of the reionization process can be probed by rest-frame UV absorption spectra of quasars at z ā‰³ 6, shedding light on the properties of the diffuse intergalactic medium within the first Gyr of the Universe. The ESO Large Programme 'XQR-30: the ultimate XSHOOTER legacy survey of quasars at z ā‰ƒ 5.8-6.6' dedicated āˆ¼250 h of observations at the VLT to create a homogeneous and high-quality sample of spectra of 30 luminous quasars at z āˆ¼6, covering the rest wavelength range from the Lyman limit to beyond the Mg ii emission. Twelve quasar spectra of similar quality from the XSHOOTER archive were added to form the enlarged XQR-30 sample, corresponding to a total of āˆ¼350 h of on-source exposure time. The median effective resolving power of the 42 spectra is R ā‰ƒ 11 400 and 9800 in the VIS and NIR arm, respectively. The signal-to-noise ratio per 10 km s-1 pixel ranges from āˆ¼11 to 114 at Ī» ā‰ƒ 1285 ƅ rest frame, with a median value of āˆ¼29. We describe the observations, data reduction, and analysis of the spectra, together with some first results based on the E-XQR-30 sample. New photometry in the H and K bands are provided for the XQR-30 quasars, together with composite spectra whose characteristics reflect the large absolute magnitudes of the sample. The composite and the reduced spectra are released to the community through a public repository, and will enable a range of studies addressing outstanding questions regarding the first Gyr of the Universe

    Mineral phosphorus drives glacier algal blooms on the Greenland Ice Sheet

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    Melting of the Greenland Ice Sheet is a leading cause of land-ice mass loss and cryosphere-attributed sea level rise. Blooms of pigmented glacier iceĀ algae lower ice albedo and accelerate surface melting in the ice sheetā€™s southwest sector. Although glacier iceĀ algae cause up to 13% of the surface melting in this region, the controls on bloom development remain poorly understood. Here we show a direct link between mineral phosphorus in surface ice and glacier iceĀ algae biomass through the quantification of solid and fluid phase phosphorus reservoirs in surface habitats across the southwest ablation zone of the ice sheet. We demonstrate that nutrients from mineral dust likely drive glacier iceĀ algal growth, and thereby identify mineral dust as a secondary control on ice sheet melting.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

    Oncogenic role of EAPII in lung cancer development and its activation of the MAPKā€“ERK pathway

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    Cancer progression involves multiple complex and interdependent steps, including progressive proliferation, angiogenesis and metastases. The complexity of these processes requires a comprehensive elucidation of the integrated signaling networks for better understanding. EAPII interacts with multiple cancer-related proteins, but its biological significance in cancer development remains unknown. In this report we identified the elevated level of EAPII protein in non-small-cell lung carcinoma (NSCLC) patients and NSCLC cell lines in culture. The oncogenic role of EAPII in lung cancer development was demonstrated using NSCLC cells with genetic manipulations that influence EAPII expression: EAPII overexpression increases proliferation of NSCLC cells with an accelerated transition of cell cycle and facilitates xenograft tumor growth in vivo; EAPII knockdown results in apoptosis of NSCLC cells and reduces xenograft tumor formation. To further explore the mechanism of EAPII's oncogenic role in lung cancer development and to elucidate the potential signaling pathway(s) that EAPII may impact, we employed antibody array to investigate the alternation of the major signaling pathways in NSCLC cells with altered EAPII level. We found that EAPII overexpression significantly activated Raf1 and ERK1/2, but not c-Jun N-terminal kinase and p38 pathways. Consistently, the protein and mRNA levels of MYC and cyclin D1, which are targets of the mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPKā€“ERK) pathway, are significantly increased by EAPII overexpression. Taken together, we demonstrated that EAPII is an oncogenic factor and the activation of MAPKā€“ERK signaling pathway by EAPII may contribute to lung cancer development

    Prothymosin alpha: a ubiquitous polypeptide with potential use in cancer diagnosis and therapy

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    The thymus is a central lymphoid organ with crucial role in generating T cells and maintaining homeostasis of the immune system. More than 30 peptides, initially referred to as ā€œthymic hormones,ā€ are produced by this gland. Although the majority of them have not been proven to be thymus-speciWc, thymic peptides comprise an eVective group of regulators, mediating important immune functions. Thymosin fraction Wve (TFV) was the Wrst thymic extract shown to stimulate lymphocyte proliferation and diVerentiation. Subsequent fractionation of TFV led to the isolation and characterization of a series of immunoactive peptides/polypeptides, members of the thymosin family. Extensive research on prothymosin (proT) and thymosin 1 (T1) showed that they are of clinical signiWcance and potential medical use. They may serve as molecular markers for cancer prognosis and/or as therapeutic agents for treating immunodeWciencies, autoimmune diseases and malignancies. Although the molecular mechanisms underlying their eVect are yet not fully elucidated proT and T1 could be considered as candidates for cancer immunotherapy. In this review, we will focus in principle on the eventual clinical utility of proT, both as a tumor biomarker and in triggering anticancer immune responses. Considering the experience acquired via the use of T1 to treat cancer patients, we will also discuss potential approaches for the future introduction of proT into the clinical setting
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