457 research outputs found
Time to focus on circulating nucleic acids for diagnosis and monitoring of gliomas: a systematic review of their role as biomarkers
Gliomas are diffusely growing tumours arising from progenitors within the central nervous system. They encompass a range of different molecular types and subtypes, many of which have a well‐defined profile of driver mutations, copy number changes, and DNA methylation patterns. A majority of gliomas will require surgical intervention to relieve raised intracranial pressure and reduce tumour burden. A proportion of tumours, however, are located in neurologically sensitive areas and a biopsy poses a significant risk of a deficit. A majority of gliomas recur after surgery, and monitoring tumour burden of the recurrence is currently achieved by imaging. However, most imaging modalities have limitations in assessing tumour burden and infiltration into adjacent brain, and sometimes imaging is unable to discriminate between tumour recurrence and pseudo‐progression. Liquid biopsies, obtained from body fluids such as cerebrospinal fluid or blood, contain circulating nucleic acids or extracellular vesicles containing tumour‐derived components. The studies for this systematic review were selected according to PRISMA criteria, and suggest that the detection of circulating tumour‐derived nucleic acids holds great promises as biomarker to aid diagnosis and prognostication by monitoring tumour progression, and thus can be considered a pathway towards personalized medicin
The influence of copolymer composition on PLGA/nHA scaffolds´ cytotoxicity and in vitro degradation
The influence of copolymer composition on Poly(Lactide-co-Glycolide)/ nanohydroxyapatite (PLGA/nHA) composite scaffolds is studied in the context of bone tissue engineering and regenerative medicine. The composite scaffolds are fabricated by thermally-induced phase separation and the effect of bioactive nanoparticles on their in vitro degradation in phosphate-buffered solution at 37 °C is analyzed over eight weeks. The indirect cytotoxicity evaluation of the samples followed an adaptation of the ISO 10993-5 standard test method. Based on the measurement of their molecular weight, molar mass, pH, water absorption and dimensions, the porous scaffolds of PLGA with a lower lactide/glycolide (LA/GA) molar ratio degraded faster due to their higher hydrophilicity. All of the samples without and with HA are not cytotoxic, demonstrating their potential for tissue engineering applications.SGIker (UPV/EHU, MICINN, GV/EJ, ERDF and ESF) is really appreciated. This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013 and Grant SFRH/BD/111478/2015 (S.R). The authors acknowledge funding by the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2016-76039-C4-3-R (Agencia Estatal de Investigación(AEI)/FEDER, Unión Europea(UE))info:eu-repo/semantics/publishedVersio
3D cytocompatible composites of PCL/Magnetite
A study of Magnetite (Fe3O4) as a suitable matrix for the improved adhesion and proliferation of MC3T3-E1 pre-osteoblast cells in bone regeneration is presented. Biodegradable and magnetic polycaprolactone (PCL)/magnetite (Fe3O4) scaffolds, which were fabricated by Thermally Induced Phase Separation, are likewise analyzed. Various techniques are used to investigate in vitro degradation at 37 °C, over 104 weeks, in a phosphate buffered saline (PBS) solution. Magnetic measurements that were performed at physiological temperature (310 K) indicated that degradation neither modified the nature nor the distribution of the magnetite nanoparticles. The coercive field strength of the porous matrices demonstrated ferromagnetic behavior and the probable presence of particle interactions. The added nanoparticles facilitated the absorption of PBS, with no considerable increase in matrix degradation rates, as shown by the Gel Permeation Chromatography (GPC) results for Mw, Mn, and I. There was no collapse of the scaffold structures that maintained their structural integrity. Their suitability for bone regeneration was also supported by the absence of matrix cytotoxicity in assays, even after additions of up to 20% magnetite.This work was supported by the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2016-76039-C4-3-R (AEI/FEDER, UE) and from the Basque Government Industry Department under the ELKARTEK, HAZITEK and PIBA programs. Supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013, project POCI-01-0145-FEDER-028237 and grant SFRH/BD/111478/2015 (S.R.) is acknowledged.Technical and human support provided by SGIker (UPV/EHU, MICINN, GV/EJ, ERDF and ESF) is gratefully appreciated. The authors acknowledge funding by the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2016-76039-C4-3-R (AEI/FEDER, UE) and from the Basque Government Industry and Education Department under the ELKARTEK and HAZITEK and PIBA (PIBA-2018-06) programs. Supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013, project POCI-01-0145-FEDER-028237 and grant SFRH/BD/111478/2015 (S.R.) is acknowledged
BioDR : semantic indexing networks for biomedical document retrieval
In Biomedical research, retrieving documents that match an interesting query is a task performed quite
frequently. Typically, the set of obtained results is extensive containing many non-interesting documents
and consists in a flat list, i.e., not organized or indexed in any way. This work proposes BioDR, a novel
approach that allows the semantic indexing of the results of a query, by identifying relevant terms in
the documents. These terms emerge from a process of Named Entity Recognition that annotates occurrences
of biological terms (e.g. genes or proteins) in abstracts or full-texts. The system is based on a learning
process that builds an Enhanced Instance Retrieval Network (EIRN) from a set of manually classified
documents, regarding their relevance to a given problem. The resulting EIRN implements the semantic
indexing of documents and terms, allowing for enhanced navigation and visualization tools, as well as
the assessment of relevance for new documents.Fundação para a Ciência e a Tecnologia (FCT)Maria Barbeito” contract XuntaHUELLA financed by the Consellería de Sanidade (Xunta de Galicia de Galicia
On the Tractability of (k, i)-Coloring
In an undirected graph, a proper (
k, i
)-coloring is an assign-
ment of a set of
k
colors to each vertex such that any two adjacent
vertices have at most
i
common colors. The (
k, i
)-coloring problem is
to compute the minimum number of colors required for a proper
(
k, i
)-
coloring. This is a generalization of the classic graph colo
ring problem.
Majumdar et. al. [CALDAM 2017] studied this problem and show
ed
that the decision version of the (
k, i
)-coloring problem is fixed parameter
tractable (FPT) with tree-width as the parameter. They aske
d if there
exists an FPT algorithm with the size of the feedback vertex s
et (FVS)
as the parameter without using tree-width machinery. We ans
wer this in
positive by giving a parameterized algorithm with the size o
f the FVS
as the parameter. We also give a faster and simpler exact algo
rithm for
(
k, k
−
1)-coloring, and make progress on the NP-completeness of sp
ecific
cases of (
k, i
)-colorin
Variations in the main pollen season of Olea Europaea L. at selected sites in the Iberian Peninsula
MY Camelopardalis, a very massive merger progenitor
Context. The early-type binary MY Cam belongs to the young open cluster
Alicante 1, embedded in Cam OB3. Aims. MY Cam consists of two early-O type
main-sequence stars and shows a photometric modulation suggesting an orbital
period slightly above one day. We intend to confirm this orbital period and
derive orbital and stellar parameters. Methods. Timing analysis of a very
exhaustive (4607 points) light curve indicates a period of 1.1754514 +-
0.0000015 d. High- resolution spectra and the cross-correlation technique
implemented in the TODCOR program were used to derive radial velocities and
obtain the corresponding radial velocity curves for MY Cam. Modelling with the
stellar atmosphere code FASTWIND was used to obtain stellar parameters and
create templates for cross-correlation. Stellar and orbital parameters were
derived using the Wilson-Devinney code, such that a complete solution to the
binary system could be described. Results. The determined masses of the primary
and secondary stars in MY Cam are 37.7 +- 1.6 and 31.6 +- 1.4 Msol,
respectively. The corresponding temperatures, derived from the model atmosphere
fit, are 42 000 and 39 000 K, with the more massive component being hotter.
Both stars are overfilling their Roche lobes, sharing a common envelope.
Conclusions. MY Cam contains the most massive dwarf O-type stars found so far
in an eclipsing binary. Both components are still on the main sequence, and
probably not far from the zero-age main sequence. The system is a likely merger
progenitor, owing to its very short period.Comment: 8 pages, 6 figures, photometric data available on-line, Astronomy and
Astrophysics, 201
Uncovering production of specialized metabolites by Streptomyces argillaceus: Activation of cryptic biosynthesis gene clusters using nutritional and genetic approaches
Spectral changes during dipping in low-mass X-ray binaries due to highly-ionized absorbers
X-ray observations have revealed that many microquasars and low-mass X-ray
binaries (LMXBs) exhibit narrow absorption features identified with resonant
absorption from Fe XXV and Fe XXVI and other abundant ions. In many well
studied systems there is evidence for blue-shifts, indicating outflowing
plasmas. We succesfully model the changes in both the X-ray continuum and the
Fe absorption features during dips from all the bright dipping LMXBs observed
by XMM-Newton (EXO 0748-676, XB 1254-690, X 1624-490, MXB 1659-298, 4U 1746-371
and XB 1916-053) as resulting primarily from an increase in column density and
a decrease in the ionization state of a highly-ionized absorber in a similar
way as was done for 4U 1323-62. This implies that the complex spectral changes
in the X-ray continua observed from the dip sources as a class can be most
simply explained primarily by changes in the highly ionized absorbers present
in these systems. There is no need to invoke unusual abundances or partial
covering of extended emission regions. Outside of the dips, the absorption line
properties do not vary strongly with orbital phase. This implies that the
ionized plasma has a cylindrical geometry with a maximum column density close
to the plane of the accretion disk. Since dipping sources are simply normal
LMXBs viewed from close to the orbital plane this implies that ionized plasmas
are a common feature of LMXBs.Comment: 19 pages, 11 figures, accepted for publication by Astronomy and
Astrophysic
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