1,720,983 research outputs found
Voltage-Dependent Anion Selective Channel 3: Unraveling Structural and Functional Features of the Least Known Porin Isoform
Full text link: Voltage-dependent anion-selective channels (VDAC) are pore-forming proteins located in the outer mitochondrial membrane. Three isoforms are encoded by separate genes in mammals (VDAC1-3). These proteins play a crucial role in the cell, forming the primary interface between mitochondrial and cellular metabolisms. Research on the role of VDACs in the cell is a rapidly growing field, but the function of VDAC3 remains elusive. The high-sequence similarity between isoforms suggests a similar pore-forming structure. Electrophysiological analyzes revealed that VDAC3 works as a channel; however, its gating and regulation remain debated. A comparison between VDAC3 and VDAC1-2 underlines the presence of a higher number of cysteines in both isoforms 2 and 3. Recent mass spectrometry data demonstrated that the redox state of VDAC3 cysteines is evolutionarily conserved. Accordingly, these residues were always detected as totally reduced or partially oxidized, thus susceptible to disulfide exchange. The deletion of selected cysteines significantly influences the function of the channel. Some cysteine mutants of VDAC3 exhibited distinct kinetic behavior, conductance values and voltage dependence, suggesting that channel activity can be modulated by cysteine reduction/oxidation. These properties point to VDAC3 as a possible marker of redox signaling in the mitochondrial intermembrane space. Here, we summarize our current knowledge about VDAC3 predicted structure, physiological role and regulation, and possible future directions in this research field
Estensione della chirurgia nei carcinomi differenziati della tiroide a basso rischio: analisi retrospettiva della casistica di un Centro di Riferimento
No full textBACKGROUND: thyroid cancer is the most commn endocrine cancer and its incidence is increasing wordwide; despite this rising incidence, mortality rates have continued to decline.
The extent of thyroid resection for well-differentiated low risk thyroid cancers is still controversial; the most recent Guidelines by the American Thyroid Association suggest that, for patients with papillary carcinoma smaller than 4 cm, without extra-thyroid extension and without clinically positive lymph nodes, the initial treatment can be either a bilateral procedure or a thyroid lobectomy, since the low risk of long-term recurrence and the excellent prognosis of these tumors.
The primary aim of this study is to evalute the extent of disease, both in the thyroid and lymph nodes, in patients undergoing total thyroidectomy +/- prophylactic central neck dissection for a single thyroid nodule with indeterminate or malignant cytology.
Secondary objective is to verify whether a less aggressive surgical approach can allow adequate oncological radicality with less morbidity.
MATERIALS AND METHODS: we retrospectly analyzed the data of patients undergoing total thyroidectomy +/- prophylactic central neck dissection for a single thyroid nodule with indeterminate cytology and BRAF mutation, or for intrathyroid unifocal cT1T2cN0 papillary thyroid carcinoma who were treated in our Department from Jenuary 2012 to December 2019.
RESULTS: patients included in the study were 83 (mean age 48.7 years, median 49 years) of wich 62 women (74.7%, mean age 49.4 years, median 49 years) and 21 men (25.3%, mean age 46.6 years, median 49 years).
Histologically 82 patients were affected by papillary carcinoma and 1 by follicular carcinoma (mean size 14.2 mm, range 1-40 mm).
Fifty patients (60.2%, 39 women and 11 men) were N0, and thirty three (39.8%, 23 women and 10 men) were N1.
Regarding the numebr of positive lymph nodes, 28 patients had a number of involved lymph nodes ≤ 5, while in 5 patients the number of positive lymph nodes was ≥ 6.
Among N0 patients, 45 patients had a carcinoma smaller than 20 mm and in 5 patients the carcinoma was between 21-40 mm.
When considering TNM classification, 40 patients were pT1, 4 patients pT2 and 6 patients pT3. Finally, in this group of patients 14 had bilateral disease.
Among N1 patients, 25 had a carcinoma smaller than 20 mm and in 8 patients the carcinoma was between 21 and 40 mm. Twenty-two patients were pT1, 9 patients pT2 and 2 patients pT3. In 6 of these patients the disease was bilateral.
If these patients had undergone lobectomy alone, 47 patients (56.6%) would have had residual disease; if the patients had undergone lobectomy and ipsilateral prophylactic central neck dissection, contralateral disease would have remained in 20 patients (24.1%), represented in all cases by microcarcinomas.
CONCLUSIONS: for patients with papillary thyroid carcinoma smaller than 4 centimeters, without extra-thyroid extension and without clinically positive lymph nodes, lobectomy associated with ipsilateral prophylactic central neck dissection can be considered a valid therapeutic option both from the point of view of oncological outcome and post-operative morbidity
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
Editorial: Molecular basis of the energy management in cells: implications in health and disease
Full text linkAppropriate 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
Generation of artificial channels by multimerization of beta-strands from natural porin
No full textGeneral diffusion porins are passive transmembrane channels. We have
explored the possibility to create artificial nanopores starting from
natural beta-barrel structures. Structural elements of bacterial porins
were used to build a series of artificial nanopores. The basic module
was selected by multi-alignment of general diffusion porins. The
sequence corresponded to a highly conserved motif containing two
beta-strands, which was obtained from Escherichia coli OmpF. Dimeric to
octameric repeats were obtained through cDNA recombinant technology. The
hexameric repeat was used to test its properties. This protein was
expressed, purified and reconstituted in the planar bilayer membranes.
It was able to form channels in membranes with a conductance of 300 pS
in 150 mM KCl and did not show any relevant voltage-dependence
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
- …
