130 research outputs found

    Study of pretesting effects on electroexplosive devices

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    Pretesting techniques of suppliers and users and effects on electroexplosive device

    Convergence of Wnt signalling on the HNF4a-driven transcription in controlling liver zonation

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    BACKGROUND & AIMS: In each hepatocyte, the specific repertoire of gene expression is influenced by its exact location along the portocentrovenular axis of the hepatic lobule and provides a reason for the liver functions compartmentalization defined "metabolic zonation." So far, few molecular players controlling genetic programs of periportal (PP) and perivenular (PV) hepatocytes have been identified; the elucidation of zonation mechanisms remains a challenge for experimental hepatology. Recently, a key role in induction and maintenance of the hepatocyte heterogeneity has been ascribed to Wnt/beta-catenin pathway. We sought to clarify how this wide-ranging stimulus integrates with hepatocyte specificity. METHODS: Reverse transcriptase polymerase chain reaction (RT-PCR) allowed the transcriptional profiling of hepatocytes derived from in vitro differentiation of liver stem cells. The GSK3beta inhibitor 6-bromoindirubin-3'-oxime (BIO) was used for beta-catenin stabilization. Co-immunoprecipitations were used to study biochemical protein interactions while ChIP assays allowed the in vivo inspection of PV and PP genes regulatory regions. RESULTS: We found that spontaneous differentiation of liver stem cells gives rise to PP hepatocytes that, after Wnt pathway activation, switch into PV hepatocytes. Next, we showed that the Wnt downstream player LEF1 interacts with the liver-enriched transcriptional factor HNF4alpha. Finally, we unveiled that the BIO induced activation of PV genes correlates with LEF1 binding to both its own and HNF4alpha consensus, and the repression of PP genes correlates with HNF4alpha displacement from its own consensus. CONCLUSION: Our data show a direct and hitherto unknown convergence of the canonical Wnt signaling on the HNF4alpha-driven transcription providing evidences of a mechanism controlling liver zonated gene expression

    Pottery technology at the dawn of metallurgy in the Vinča culture

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    This chapter summarises the macroscopic and microscopic analyses of pottery sherds from the sites of Belovode and Pločnik, presented in Chapters 14 and 31, and provides insight into different technological traits in order to aid reconstruction of pottery making recipes in these two Vinča culture communities. Using a multi- pronged scientific approach, we reconstructed routines of raw material acquisition and processing, techniques of forming and finishing vessels, firing conditions and organisational aspects of pottery production. The possible non-local production identified in this research is also considered in order to understand the dynamics that shaped pottery circulation in these prehistoric communities (e.g. Quinn et al. 2010). These results also contribute significantly to the previous technological studies carried out on Neolithic pottery from sites in the central Balkans (Figure 1) (e.g. Dammers et al. 2012; Kaiser 1984, 1989, 1990; Kaiser et al. 1986; Kreiter et al. 2009, 2011, 2013, 2017a, 2017b, 2019; Spataro 2014, 2017, 2018; Szakmány et al. 2019)

    Pyrotechnological connections? Re-investigating the link between pottery firing technology and the origins of metallurgy in the Vinča Culture, Serbia

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    The present paper re-examines the purported relationship between Late Neolithic/Early Chalcolithic pottery firing technology and the world's earliest recorded copper metallurgy at two Serbian Vinča culture sites, Belovode and Pločnik (c. 5350 to 4600 BC). A total of eighty-eight well-dated sherds including dark-burnished and graphite-painted pottery that originate across this period have been analysed using a multi-pronged scientific approach in order to reconstruct the raw materials and firing conditions that were necessary for the production of these decorative styles. This is then compared to the pyrotechnological requirements and chronology of copper smelting in order to shed new light on the assumed, yet rarely investigated, hypothesis that advances in pottery firing technology in the late 6th and early 5th millennia BC Balkans were an important precursor for the emergence of metallurgy in this region at around 5000 BC. The results of this study and the recent literature indicate that the ability to exert sufficiently close control over the redox atmosphere in a two-step firing process necessary to produce graphite-painted pottery could indeed link these two crafts. However, graphite-painted pottery and metallurgy emerge at around the same time, both benefitting from the pre-existing experience with dark-burnished pottery and an increasing focus on aesthetics and exotic minerals. Thus, they appear as related technologies, but not as one being the precursor to the other

    Therapeutic advances in ADPKD: the future awaits

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    Autosomal dominant polycystic kidney disease (ADPKD) is a heterogeneous genetic disorder included in ciliopathies, representing the fourth cause of end stage renal disease (ESRD), with an estimated prevalence between 1:1000 and 1:2500. It is mainly caused by mutations in the PKD1 and PKD2 genes encoding for polycystin 1 (PC1) and polycystin 2 (PC2), which regulate differentiation, proliferation, survival, apoptosis, and autophagy. The advances in the knowledge of multiple molecular pathways involved in the pathophysiology of ADPKD led to the development of several treatments which are currently under investigation. Recently, the widespread approval of tolvaptan and, in Italy, of long-acting release octreotide (octreotide-LAR), represents but the beginning of the new therapeutic management of ADPKD patients. Encouraging results are expected from ongoing randomized controlled trials (RCTs), which are investigating not only drugs acting on the calcium/cyclic adenosin monoposphate (cAMP) pathway, the most studied target so far, but also molecules targeting specific pathophysiological pathways (e.g. epidermal growth factor (EGF) receptor, AMP-activated protein kinase (AMPK) and KEAP1-Nrf2) and sphingolipids. Moreover, studies on animal models and cultured cells have also provided further promising therapeutic strategies based on the role of intracellular calcium, cell cycle regulation, MAPK pathway, epigenetic DNA, interstitial inflammation, and cell therapy. Thus, in a near future, tailored therapy could be the key to changing the natural history of ADPKD thanks to the vigorous efforts that are being made to implement clinical and preclinical studies in this field. Our review aimed to summarize the spectrum of drugs that are available in the clinical practice and the most promising molecules undergoing clinical, animal, and cultured cell studies. Graphical abstract: [Figure not available: see fulltext.

    Two modes of evolution shape bacterial strain diversity in the mammalian gut for thousands of generations

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    How and at what pace bacteria evolve when colonizing healthy hosts remains unclear. Here, by monitoring evolution for more than six thousand generations in the mouse gut, we show that the successful colonization of an invader Escherichia coli depends on the diversity of the existing microbiota and the presence of a closely related strain. Following colonization, two modes of evolution were observed: one in which diversifying selection leads to long-term coexistence of ecotypes and a second in which directional selection propels selective sweeps. These modes can be quantitatively distinguished by the statistics of mutation trajectories. In our experiments, diversifying selection was marked by the emergence of metabolic mutations, and directional selection by acquisition of prophages, which bring their own benefits and costs. In both modes, we observed parallel evolution, with mutation accumulation rates comparable to those typically observed in vitro on similar time scales. Our results show how rapid ecotype formation and phage domestication can be in the mammalian gut.info:eu-repo/semantics/publishedVersio

    Stepwise shortening of agalsidase beta infusion duration in Fabry disease: Clinical experience with infusion rate escalation protocol

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    Background: Although enzyme replacement therapy with agalsidase beta resulted in a variety of clinical benefits, life-long biweekly intravenous infusion may impact on patients’ quality of life. Moreover, regular infusions are time-consuming: although a stepwise shortening of infusion duration is allowed up to a minimum of 1.5 hr, in most centers it remains ≥3 hr, and no data exists about the safety and tolerability of agalsidase beta administration at maximum tolerated infusion rate. Methods: In this study, we reported our experience with a stepwise infusion rate escalation protocol developed in our center in a cohort of 53 Fabry patients (both already receiving and treatment-naΪve), and explored factors predictive for the infusion rate increase tolerability. Results: Fifty-two patients (98%) reduced infusion duration ≤3 hr; of these, 38 (72%) even reached a duration ≤2 hr. We found a significant difference between the mean duration reached by already treated and naΪve patients (p <.01). More severely affected patients (male patients and those with lower enzyme activity) received longer infusions for higher risk of infusion-associated reactions (IARs). A significant correlation between anti-agalsidase antibodies and IARs was found. Conclusion: Our infusion rate escalation protocol is safe and could improve patient compliance, satisfaction and quality of life

    Seasonality of Births and Conceptions in a Pastoral Community of the Province of l’Aquila (Abruzzo, Italy), 1802–1965

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    Natality rates and seasonality of births and conceptions were analyzed from 6,116 birth records in the pastoral community of Roio (Abruzzo, Italy) from 1802 to 1965. Gross natality rates averaged 25.5 x 1000 in the past, lower than those reported for agricultural groups. Seasonality of births showed a marked pattern: 80%–67% of births occurred in the first six months of the year. The monthly distribution of conceptions was compared to that of marriages. The results show a high correlation in the 19th century and a lower one in the 20th century. These findings suggest that pastoralism acted as a primary regulator of reproduction in this community

    Hepatitis C virus production requires apolipoprotein A-I and affects its association with nascent low-density lipoproteins

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    Background/aims The life cycle of hepatitis C virus (HCV) is intimately linked to the lipid metabolism of the host. In particular, HCV exploits the metabolic machinery of the lipoproteins in several steps of its life cycle such as circulation in the bloodstream, cell attachment and entry, assembly and release of viral particles. However, the details of how HCV interacts with and influences the metabolism of the host lipoproteins are not well understood. A study was undertaken to investigate whether HCV directly affects the protein composition of host circulating lipoproteins. Methods A proteomic analysis of circulating very low-, low- and high-density lipoproteins (VLDL, LDL and HDL), isolated from either in-treatment naive HCV-infected patients or healthy donors (HD), was performed using two-dimensional gel electrophoresis and tandem mass spectrometry (MALDI-TOF/TOF). The results obtained were further investigated using in vitro models of HCV infection and replication. Results A decreased level of apolipoprotein A-I (apoA-I) was found in the LDL fractions of HCV-infected patients. This result was confirmed by western blot and ELISA analysis. HCV cellular models (JFH1 HCV cell culture system (HCVcc) and HCV subgenomic replicons) showed that the decreased apoA-I/LDL association originates from hepatic biogenesis rather than lipoprotein catabolism occurring in the circulation, and is not due to a downregulation of the apoA-I protein concentration. The sole non-structural viral proteins were sufficient to impair the apoA-I/LDL association. Functional evidence was obtained for involvement of apoA-I in the viral life cycle such as RNA replication and virion production. The specific siRNA-mediated downregulation of apoA-I led to a reduction in both HCV RNA and viral particle levels in culture. Conclusions This study shows that HCV induces lipoprotein structural modification and that its replication and production are linked to the host lipoprotein metabolism, suggesting apoA-I as a new possible target for antiviral therapy

    Mutation rate of SARS-CoV-2 and emergence of mutators during experimental evolution

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    Free PMC article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8996265/Background and objectives: To understand how organisms evolve, it is fundamental to study how mutations emerge and establish. Here, we estimated the rate of mutation accumulation of SARS-CoV- 2 in vitro and investigated the repeatability of its evolution when facing a new cell type but no immune or drug pressures. Methodology: We performed experimental evolution with two strains of SARS-CoV-2, one carrying the originally described spike protein (CoV-2-D) and another carrying the D614G mutation that has spread worldwide (CoV-2-G). After 15 passages in Vero cells and whole genome sequencing, we characterized the spectrum and rate of the emerging mutations and looked for evidences of selection across the genomes of both strains. Results: From the frequencies of the mutations accumulated, and excluding the genes with signals of selection, we estimate a spontaneous mutation rate of 1.3 10 6 6 0.2 10 6 per-base per-infection cycle (mean across both lineages of SARS-CoV-262SEM). We further show that mutation accumulation is larger in the CoV-2-D lineage and heterogeneous along the genome, consistent with the action of positive selection on the spike protein, which accumulated five times more mutations than the corresponding genomic average. We also observe the emergence of mutators in the CoV-2-G background, likely linked to mutations in the RNA-dependent RNA polymerase and/or in the error-correcting exonuclease protein. Conclusions and implications: These results provide valuable information on how spontaneous mutations emerge in SARS-CoV-2 and on how selection can shape its genome toward adaptation to new environments. Lay Summary: Each time a virus replicates inside a cell, errors (mutations) occur. Here, via laboratory propagation in cells originally isolated from the kidney epithelium of African green monkeys, we estimated the rate at which the SARS-CoV-2 virus mutates—an important parameter for understanding how it can evolve within and across humans. We also confirm the potential of its Spike protein to adapt to a new environment and report the emergence of mutators—viral populations where mutations occur at a significantly faster rate.M.A. was supported by ‘Fundação para a Ciência e Tecnologia’ (FCT), fellowships PD/BD/138735/2018. Research was supported by FCT Project PTDC/BIA-EVL/31528/2017 to I.G. and by funds from Portuguese NIH.info:eu-repo/semantics/publishedVersio
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