3,965 research outputs found

    Study of the Influence of Helical Milling Parameters on the Quality of Holes in the UNS R56400 Alloy

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    Helical milling has been positioned as an alternative to conventional drilling, where the advantages it offers make it very attractive for use on difficult-to-machine alloys such as the titanium alloy UNS R56400. However, the correlation between the indicator of hole quality and the kinematic parameters has rarely been studied. The kinematics are what bring most advantages and that is why it is necessary to know their influence. In this aspect, there are different focuses of problems associated with the complexity of the process kinematics, which makes it necessary to undertake a deeper analysis of the process and to carry out a preliminary study. To address this problem, a DOE (Design of Experiments) is proposed to identify the sensitivity and the main trends of the properties that define the quality holes with respect to the kinematic parameters. At the same time, a nomenclature is proposed to unify and avoid misinterpretations. This study has allowed us to obtain conclusive results that offer very relevant information for future researc

    Insomnia Symptoms and Associated Factors in Caregivers of Adult Hospitalized Patients

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    Caregivers experience high levels of emotional stress and must cope with several clinical and hospital-related environmental factors that seriously impact their night’s rest. The purpose of this study was to establish the prevalence of insomnia symptoms in a sample of caregivers of adult hospitalized patients and to examine the relationships between insomnia symptoms and patient and caregiver-associated factors. A total of 152 caregivers were enrolled from the two main hospitals in Granada, Spain. Sociodemographic, economic, and care-related data were collected. Insomnia symptoms, burden, anxiety and depression, social support, and resilience were assessed. Information on patients’ hospital admission, dependence, and neuropsychiatric symptoms was also obtained. Most caregivers were middle-aged women caring for their spouses. Self-reported insomnia prevalence was set at 45.4%. Comparison analyses between caregivers suffering from insomnia symptoms and non-insomniacs showed significantly higher burden, anxiety and depression and patients’ neuropsychiatric symptoms (p < 0.05) and lower resilience and social support in the former (p < 0.01). A regression analysis showed that anxiety (ORa = 1.15; p < 0.05) and higher caregiver education level (ORa = 5.50; p < 0.05) were factors significantly associated with insomnia symptoms. Patients’ neuropsychiatric symptoms showed a trend toward statistical significance as well (ORa = 1.09; p = 0.06). There is an acute need to address, prevent and treat insomnia problems in caregivers.Regional Ministry of Health of Andalusia (PI-0259-2017

    Regulation of bistability in the std fimbrial operon of Salmonella enterica by DNA adenine methylation and transcription factors HdfR, StdE and StdF

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    Bistable expression of the Salmonella enterica std operon is controlled by an AND logic gate involving three transcriptional activators: the LysR-type factor HdfR and the StdE and StdF regulators encoded by the std operon itself. StdE activates transcription of the hdfR gene, and StdF activates std transcription together with HdfR. Binding of HdfR upstream of the std promoter is hindered by methylation of GATC sites located within the upstream activating sequence (UAS). Epigenetic control by Dam methylation thus antagonizes formation of the StdE-StdF-HdfR loop and tilts the std switch toward the StdOFF state. In turn, HdfR binding hinders methylation of the UAS, permitting activation of the StdE-StdF-HdfR loop and concomitant formation of StdON cells. Bistability is thus the outcome of competition between DNA adenine methylation and the StdE-StdF-HdfR activator loop.Ministerio de Ciencia, Innovación y Universidades [BIO2016–75235-P

    A eukaryotic-like 3′ untranslated region in Salmonella enterica hilD mRNA

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    Long 3' untranslated regions (3'UTRs) are common in eukaryotic mRNAs. In contrast, long 3'UTRs are rare in bacteria, and have not been characterized in detail. We describe a 3'UTR of 310 nucleotides in hilD mRNA, a transcript that encodes a transcriptional activator of Salmonella enterica pathogenicity island 1 (SPI-1). Deletion of the hilD 3'UTR increases the hilD mRNA level, suggesting that the hilD 3'UTR may play a role in hilD mRNA turnover. Cloning of the hilD 3'UTR downstream of the green fluorescent protein (gfp) gene decreases green fluorescent protein (GFP) activity in both Escherichia coli and S. enterica, indicating that the hilD 3'UTR can act as an independent module. S. enterica mutants lacking either ribonuclease E or polynucleotide phosphorylase contain similar amounts of hilD and hilD Δ3'UTR mRNAs, suggesting that the hilD 3'UTR is a target for hilD mRNA degradation by the degradosome. The hilD 3'UTR is also necessary for modulation of hilD and SPI-1 expression by the RNA chaperone Hfq. Overexpression of SPI-1 in the absence of the hilD 3'UTR retards Salmonella growth and causes uncontrolled invasion of epithelial cells. Based on these observations, we propose that the S. enterica hilD 3'UTR is a cis-acting element that contributes to cellular homeostasis by promoting hilD mRNA turnover.Ministerio de Economía y Competitividad BIO2010- 15023 y CSD2008-00013Junta de Andalucía P10-CVI-587

    A longitudinal retrospective study on intracranial arterial pulsatility index: its evolution in ten years' time and how it relates to the occurrence of cerebral and systemic ischemic disease

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    BACKGROUND AND AIMS: Intracranial arterial pulsatility index (PI) has been related to old age, hypertension, diabetes and small vessel disease. However, the cross- sectional design of most studies prevents a proper assessment of causality and evolution. We sought to explore how this index changes through time, which conditions affect this evolution and whether or not it can predict the occurrence of future ischemic events. METHODS: Between the years 2001-2006, 1288 patients underwent a transcranial Doppler evaluation in the Department of Neurology of the Hospital Universitario Central de Asturias. PI values for the middle cerebral and basilar arteries were systematically annotated. After exclusion of deceased patients and significant large artery stenoses, 89 patients were recruited for a re-evaluation in 2012. Afterwards, the sample was expanded up to 150 patients, with 61 randomly selected patients –either alive or deceased- who did not undergo a second exploration. Both groups had their clinical files reviewed, with special attention to vascular risk factors and brain or coronary ischemic events. RESULTS AND DISCUSSION: Our results pointed to the following conclusions: • Intracranial arterial PI works as a dynamic measure of both cerebral and systemic vascular disease. • Age is the main factor influencing PI value and variation, but, within a certain age group, PI is able to point subjects at higher long-term risk of future ischemic events. • Basilar artery PI seems to be a better predictor of future cerebral and coronary ischemic disease than middle cerebral artery PI

    Morpholigical study of honey bees on the Canary Islands (Gran Canaria, Tenerife, La Palma, Gomera)

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    A morphological study was made of worker bees from 49 hives located at four island from the Canary archipelago. The study analysed 18 morphological characters and we have found that the bees from Gran Canaria and Tenerife belong to the same groupe, the animals from Gomera constitute a group near the afore mentioned, and the bees from La Palma form an independent group. Also, we have compared the data with data to come from hives placed in the south of the Iberian peninsula and in the north of Africa. We have found that the bees from Africa form an independent group, and the bees from the Iberian peninsula are included in the La Palma group.Se ha llevado a cabo un estudio morfológico de las abejas obreras procedentes de 49 colmenas situadas en cuatro islas del Archipiélago Canario. Se han analizado 18 características morfológicas, encontrando que las abejas procedentes de Gran Canaria y Tenerife pertenecen al mismo grupo; los animales de Gomera constituyen un grupo cercano al anterior y las abejas de La Palma forman un grupo independiente. También hemos comparado los datos obtenidos, con los procedentes de colmenas situadas en el sur de la península Ibérica y en el norte de África. Encontramos que las abejas del norte de África constituyen un grupo independiente y que los animales del sur de la península se incluyen en el grupo de las abejas de La Palma

    On a Non-Discrete Concept of Prokaryotic Species

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    The taxonomic concept of species has received continuous attention. A microbial species as a discrete box contains a limited number of highly similar microorganisms assigned to that taxon, following a polyphasic approach. In the 21st Century, with the advancements of sequencing technologies and genomics, the existence of a huge prokaryotic diversity has become well known. At present, the prokaryotic species might no longer have to be understood as discrete values (such as 1 or 2, by homology to Natural numbers); rather, it is expected that some microorganisms could be potentially distributed (according to their genome features and phenotypes) in between others (such as decimal numbers between 1 and 2; real numbers). We propose a continuous species concept for microorganisms, which adapts to the current knowledge on the huge diversity, variability and heterogeneity existing among bacteria and archaea. Likely, this concept could be extended to eukaryotic microorganisms. The continuous species concept considers a species to be delimited by the distance between a range of variable features following a Gaussian-type distribution around a reference organism (i.e., its type strain). Some potential pros and cons of a continuous concept are commented on, offering novel perspectives on our understanding of the highly diversified prokaryotic world, thus promoting discussion and further investigation in the field.info:eu-repo/semantics/publishedVersio
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