Hybrid systems are presented as a viable, safe and effective solution to minimize the associated problems of the dependence on renewable energies with the environmental resources. In this way ...different renewable systems such as photovoltaic, wind, hydrogen and so on, can work together to configure hybrid renewable systems. However, to make them work properly in a holistic way by creating synergies among them is not an easy task. Recently hydrogen technology has appeared as a promising technology to hybridize renewable energy systems, since it allows the generation (by electrolyzers) and storage of hydrogen when there is a surplus of energy in the system, and at a later time (e.g. when there are insufficient renewable resources available) using the stored hydrogen to generate electrical energy by fuel cells. The choice of a correct energy management strategy should guarantee an optimum performance of the whole hybrid renewable system; therefore, it is necessary to know the most important criteria in order to define a management strategy that ensures the best solution from a technical and economic point of view. This paper presents a critical review and analysis of different energy management strategies for hybrid renewable systems based on hydrogen backup. In the same way, a review is also presented of the most important technical and economic optimization criteria, as well as problems and solutions studied in the scientific literature.
Neural progenitors derived from iPSCs of patients with multiple system atrophy show changes in the mitochondrial morphology, relocation of α‐synuclein to the nucleus, and increased susceptibility to ...exogenous oxidative stress. The findings suggest early cellular dysfunction preceding α‐synuclein aggregate formation in this disorder.
Aims
Multiple system atrophy (MSA) is a fatal neurodegenerative disease that belongs to the family of α‐synucleinopathies. At post mortem examination, intracellular inclusions of misfolded α‐synuclein are found in neurons and oligodendrocytes and are considered to play a significant role in the pathogenesis. However, the early steps of the disease process are unknown and difficult to study in tissue derived from end‐stage disease.
Methods
Induced pluripotent stem cells (iPSCs) were generated from patients’ and control skin fibroblasts and differentiated into NCAM‐positive neural progenitor cells (NPCs). The mitochondrial morphology and function were assessed by immunocytochemistry and high resolution respirometry. The ability to cope with exogenous oxidative stress was tested by exposure to different doses of luperox. The expression of α‐synuclein was studied by immunocytochemistry.
Results
We identified increased tubulation of mitochondria with preserved respiration profile in MSA‐derived NPCs. Exposure of these cells to exogenous oxidative stress even at low doses, triggered an excessive generation of reactive oxygen species (ROS) and cleavage of caspase‐3. MSA‐derived NPCs did not present changed levels of SNCA gene expression nor intracellular aggregates of α‐synuclein. However, we identified disease‐related translocation of α‐synuclein to the nucleus.
Conclusions
Our results show early cellular dysfunction in MSA‐derived NPCs. We identified changes in the redox homeostasis which are functionally compensated at baseline but cause increased susceptibility to exogenous oxidative stress. In addition, nuclear translocation of α‐synuclein in MSA‐derived NPCs supports an early cellular stress response which may precede the neurodegenerative process in this disorder.
•Chitosan oligosaccharides (COS) were prepared by an enzymatic one-step process (P1).•COS P2 were prepared by two-step process combining chemical and enzymatic reaction.•COS P2 was composed of a ...great proportion of fully deacetylated sequences (63%).•COS P1 showed the strongest growth inhibition for E. coli and L. monocytogenes.•N-acetyl-glucosamine sequences are necessary to exert good antibacterial capacity.
The bioactivities of chitooligosaccharides are markedly influenced by the degree of acetylation, degree of polymerization or molecular weight and pattern of acetylation. Thus, it is crucial to identify reproducible processes that will give rise to well-defined chitooligosaccharides and establish methods for their posterior physicochemical characterization in order to advance in the knowledge of their bioactivity. Chitooligosaccharides were prepared by two different processes. The first used chitosanase enzymatic hydrolysis and the second consisted of a two-step procedure based on chemical hydrolysis followed by chitosanase hydrolysis. Chitooligosaccharides produced in the second process were composed of 63 % of fully deacetylated sequences and inhibited the growth of Escherichia coli and Listeria monocytogenes. Better antibacterial activity was found for those obtained in the first process composed of 27 % of fully deacetylated sequences. Therefore, a low percentage of free amino groups and the presence of acetylated sequences are necessary in these molecules to exert good antibacterial capacity.
Background
Carotid paragangliomas are rare tumors. They are usually unique, non‐secreting, resectable, and benign. However, additional rare cases of complex tumors (bilateral, secretory, ...nonresectable, or malignant) complicate the management and final outcomes.
Methods
Records of paragangliomas from our hospital are reviewed. Criteria defining complex paragangliomas have been previously defined. These are compared with those of the simple group.
Results
Fifty patients, two groups: simple (n = 39) and complex (n = 11). The patients in the complex group were significantly younger (47.7 vs 63.8 years). Postoperative nerve complications (45.4% vs 6.3%) and mortality during follow‐up (27.3% vs 0%) were significantly more common in the complex group. Vascular complications (0% vs 3.1%) and early mortality (0%) were similarly in both groups.
Conclusions
Patients with complex carotid paragangliomas are heterogeneous. The former are younger, exhibit a high degree of diagnostic and therapeutic complexity, and have poorer morbidity and mortality. Surgical experience and interdisciplinary collaboration are essential.
The all-sky PLATO input catalogue Montalto, M.; Piotto, G.; Marrese, P. M. ...
Astronomy and astrophysics (Berlin),
09/2021, Volume:
653
Journal Article
Peer reviewed
Open access
Context.
The ESA PLAnetary Transits and Oscillations of stars (PLATO) mission will search for terrestrial planets in the habitable zone of solar-type stars. Because of telemetry limitations, PLATO ...targets need to be pre-selected.
Aims.
In this paper, we present an all sky catalogue that will be fundamental to selecting the best PLATO fields and the most promising target stars, deriving their basic parameters, analysing the instrumental performances, and then planing and optimising follow-up observations. This catalogue also represents a valuable resource for the general definition of stellar samples optimised for the search of transiting planets.
Methods.
We used
Gaia
Data Release 2 astrometry and photometry and 3D maps of the local interstellar medium to isolate FGK (
V
≤ 13) and M (
V
≤ 16) dwarfs and subgiant stars.
Results.
We present the first public release of the all-sky PLATO input catalogue (asPIC1.1) containing a total of 2 675 539 stars including 2 378 177 FGK dwarfs and subgiants and 297 362 M dwarfs. The median distance in our sample is 428 pc for FGK stars and 146 pc for M dwarfs, respectively. We derived the reddening of our targets and developed an algorithm to estimate stellar fundamental parameters (
T
eff
, radius, mass) from astrometric and photometric measurements.
Conclusions.
We show that the overall (internal+external) uncertainties on the stellar parameter determined in the present study are ∼230 K (4%) for the effective temperatures, ∼0.1
R
⊙
(9%) for the stellar radii, and ∼0.1
M
⊙
(11%) for the stellar mass. We release a special target list containing all known planet hosts cross-matched with our catalogue.
Context. Since it started observing the sky, the INTEGRAL satellite has discovered new categories of high mass X-ray binaries (HMXB) in our Galaxy. These observations raise important questions on the ...formation and evolution of these rare and short-lived objects. Aims. We present here new infrared observations from which to reveal or constrain the nature of 15 INTEGRAL sources, which allow us to update and discuss the Galactic HMXB population statistics. Methods. After previous photometric and spectroscopic observing campaigns in the optical and near-infrared, new photometry and spectroscopy was performed in the near-infrared with the SofI instrument on the ESO/NTT telescope in 2008 and 2010 on a sample of INTEGRAL sources. These observations, and specifically the detection of certain features in the spectra, allow the identification of these high-energy objects by comparison with published NIR spectral atlases of O and B stars. Results. We present photometric data of nine sources (IGR J10101-5654, IGR J11187-5438, IGR J11435-6109, IGR J14331-6112, IGR J16328-4726, IGR J17200-3116, IGR J17354-3255, IGR J17404-3655, and IGR J17586-2129) and spectroscopic observations of 13 sources (IGR J10101-5654, IGR J11435-6109, IGR J13020-6359, IGR J14331-6112, IGR J14488-5942, IGR J16195-4945, IGR J16318-4848, IGR J16320-4751, IGR J16328-4726, IGR J16418-4532, IGR J17354-3255, IGR J17404-3655, and IGR J17586-2129). Our spectroscopic measurements indicate that: five of these objects are Oe/Be high-mass X-ray binaries (BeHMXB), six are supergiant high-mass X-ray binaries (sgHMXB), and two are sgBe. From a statistical point of view, we estimate the proportion of confirmed sgHMXB to be 42% and that of the confirmed BeHMXB to be 49%. The remaining 9% are peculiar HMXB.
Context. Debris discs are a consequence of the planet formation process and constitute the fingerprints of planetesimal systems. Their solar system counterparts are the asteroid and Edgeworth-Kuiper ...belts. Aims. The DUNES survey aims at detecting extra-solar analogues to the Edgeworth-Kuiper belt around solar-type stars, putting in this way the solar system into context. The survey allows us to address some questions related to the prevalence and properties of planetesimal systems. Methods. We used Herschel/PACS to observe a sample of nearby FGK stars. Data at 100 and 160 μm were obtained, complemented in some cases with observations at 70 μm, and at 250, 350 and 500 μm using SPIRE. The observing strategy was to integrate as deep as possible at 100 μm to detect the stellar photosphere. Results. Debris discs have been detected at a fractional luminosity level down to several times that of the Edgeworth-Kuiper belt. The incidence rate of discs around the DUNES stars is increased from a rate of ~12.1% ± 5% before Herschel to ~20.2% ± 2%. A significant fraction (~52%) of the discs are resolved, which represents an enormous step ahead from the previously known resolved discs. Some stars are associated with faint far-IR excesses attributed to a new class of cold discs. Although it cannot be excluded that these excesses are produced by coincidental alignment of background galaxies, statistical arguments suggest that at least some of them are true debris discs. Some discs display peculiar SEDs with spectral indexes in the 70–160 μm range steeper than the Rayleigh-Jeans one. An analysis of the debris disc parameters suggests that a decrease might exist of the mean black body radius from the F-type to the K-type stars. In addition, a weak trend is suggested for a correlation of disc sizes and an anticorrelation of disc temperatures with the stellar age.
UV/Vis absorption spectroelectrochemistry is a very promising analytical technique due to the complementary information that is simultaneously obtained from electrochemistry and spectroscopy. In this ...work, this technique is used in a parallel configuration to study the oxidation of folic acid in alkaline medium. Herein, UV/Vis absorption spectroelectrochemistry has been used to detect both the oxidation products and the folic acid consumed at the electrode/solution interface, allowing us to develop an analytical protocol to quantify vitamin B9 in pharmaceutical tablets. Linear ranges of three orders of magnitude have been achieved in basic medium (pH = 12.9), obtaining high repeatability and low detection limits. The spectroelectrochemical determination of folic acid in pharmaceutical tablets at alkaline pH values is particularly interesting because of the changes that occur in the optical signal during the electrochemical oxidation of FA, providing results with very good figures of merit and demonstrating the utility and versatility of this hyphenated technique, UV/Vis absorption spectroelectrochemistry.
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