1,721,029 research outputs found
PGC1α: Friend or Foe in Cancer?
No full textThe PGC1 family (Peroxisome proliferator-activated receptor γ (PPAR γ) coactivators) of transcriptional coactivators are considered master regulators of mitochondrial biogenesis and function. The PGC1α isoform is expressed especially in metabolically active tissues, such as the liver, kidneys and brain, and responds to energy-demanding situations. Given the altered and highly adaptable metabolism of tumor cells, it is of interest to investigate PGC1α in cancer. Both high and low levels of PGC1α expression have been reported to be associated with cancer and worse prognosis, and PGC1α has been attributed with oncogenic as well as tumor suppressive features. Early in carcinogenesis PGC1α may be downregulated due to a protective anticancer role, and low levels likely reflect a glycolytic phenotype. We suggest mechanisms of PGC1α downregulation and how these might be connected to the increased cancer risk that obesity is now known to entail. Later in tumor progression PGC1α is often upregulated and is reported to contribute to increased lipid and fatty acid metabolism and/or a tumor cell phenotype with an overall metabolic plasticity that likely supports drug resistance as well as metastasis. We conclude that in cancer PGC1α is neither friend nor foe, but rather the obedient servant reacting to metabolic and environmental cues to benefit the tumor cell
Variabilità interpopolazionistica di Bufo lineatus nel pSIC “Laghi” di Conversano (Puglia) (Anura: Bufonidae)
No full textLissotriton italicus (Peracca, 1893) (Tritone italiano)
No full textExecutive summary
Handbooks for monitoring species and habitats of Community interest (Council Directive
92/43/EEC) in Italy: animal species
The Habitats Directive requires Member States to implement surveillance of the conservation status
of habitats and species of Community Interest. The aim of this handbook is to outline the methodological
instruments for implementing a monitoring program of the Italian animal species, as required by art. 17,
with particular reference to data collection at site level.
The European guidelines require the assessments to be carried out by compiling information on
specific parameters at biogeographical scale. For each animal species, four parameters have to be
considered and combined to obtain an overall assessment of conservation status for each
biogeographical region at national level: "Range" (based on actual distribution), "Population", “Habitat
for the species” and "Future Prospects". Monitoring programs need to collect data dealing with the first
three parameters at a local level.
In this handbook, a monitoring form is presented for each animal taxon (species, subspecies or
species group) of Community interest occurring in Italian terrestrial and inland water environments.
Altogether, the volume contains 151 forms, referring to 215 terrestrial and inland water animal taxa.
Further species, which will be reported in the IV National Report under a common name due to
difficulties in recognizing them in the field or their doubtful status, are mentioned and discussed as well.
Monitoring methods have been defined with the support of five national Scientific Societies, and
reviewed by personnel of the Italian Regions and Autonomous Provinces. The monitoring forms thus
report the most effective available techniques and provide an operational guidance for data collection
and monitoring scheduling with the aim of standardizing data collection efforts across Italy. A
standardized basis of information is indeed important for assembling data at national level and producing
comparable assessments on the conservation status and future prospects of each animal taxon
Sensibilità cardiopolmonare e chemosensibilità
No full textThe autonomic control of the cardiovascular system plays an important role in maintaining the arterial pressure at the levels necessary for adequate tissue perfusion. In cardiovascular diseases, the impairment of the basic reflex mechanisms that are responsible for the moment-to-moment regulation could increase sympathetic activity and is correlated with an adverse outcome. The objective of the present review was to provide information about the methodological aspects exploring cardiopulmonary and chemoreceptor reflexes. Different techniques are available and all of them include assessment of reflexes through the activation or deactivation of either the cardiopulmonary baroreceptors or chemoreceptors. Intravenous saline load, head-down tilt, passive legs raising, head-out water immersion and the application of a lower body positive pressure are the principal methods utilized for activating cardiopulmonary baroreceptors; on the contrary deactivation could be achieved by acutely induced hypovolemia by furosemide or blood donation, inflation of a congestion cuff on the thighs or application of a negative pressure on the lower body. The transient exposure to a hypoxic or a hypercapnic gas mixture is frequently used to determine the peripheral and central chemoreflexes, respectively. The reflexes are quantified by the gain between output (i.e. heart rate, sympathetic activity, vascular resistance, ventilation) and input (oxygen saturation, end-tidal CO2 or changes in central venous pressure). One important limitation in assessing the cardiopulmonary baroreflex by using currently available techniques is that the involvement of the arterial baroreflex cannot be avoided. In addition, chemoreflexes cannot be interpreted unless the breathing rate is controlled. To date, several techniques are available for the quantification of cardiopulmonary baroreceptor and chemoreceptor reflexes and could provide new information on the abnormal autonomic mechanisms contributing to the pathophysiology of several cardiovascular diseases
A novel design of ventricular assist device: An in vitro feasibility study.
No full textLeft ventricular assist devices (LVADs) work as a bypass between the left ventricular apex and the ascending aorta. The surgical procedure for their insertion requires the opening of the cardiac cavities and the dissection of the great vessels, the blood is constrained to flow through the device components and the risk can be run of thrombogenesis, haemolysis and infections. A possible strategy to overcome this limitation consists in utilizing external systems that assist the heart in its contraction from the outside without directly transporting the blood. In this study we conduct the feasibility analysis of a novel external LVAD design that does not require the opening of the cardiac cavities and the dissection of the great vessels and that allows the removal procedure to be easily achieved. The device, including a stepper motor, three metallic wires and three elastic elements, works alternatively between a contraction condition where it induces an elastic compulsion on the heart and a release condition where it elastically releases the organ. The values of force acting on the wires and the values of current supplied to the motor were measured and utilized for a preliminary study design. The experimental measurements demonstrated the feasibility of the system
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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