We here report the properties of Wolf–Rayet (W–R) stars in 14 locations in the nearby spiral galaxy M81. These locations were found serendipitously while analysing the slit spectra of a sample of ...∼150 star-forming complexes, taken using the long-slit and multiobject spectroscopic modes of the OSIRIS instrument at the 10.4-m Gran Telescopio Canarias. Colours and magnitudes of the identified point sources in the Hubble Space Telescope images compare well with those of individual W–R stars in the Milky Way. Using templates of individual W–R stars, we infer that the objects responsible for the observed W–R features are single stars in 12 locations, comprising of three WNLs, three WNEs, two WCEs and four transitional WN/C types. In diagrams involving bump luminosities and the width of the bumps, the W–R stars of the same sub-class group together, with the transitional stars occupying locations intermediate between the WNE and WCE groups, as expected from the evolutionary models. However, the observed number of 4 transitional stars out of our sample of 14 is statistically high as compared to the 4 per cent expected in stellar evolutionary models.
The bioactive compounds in myrtle berries, such as phenolic compounds and anthocyanins, have shown a potentially positive effect on human health. Efficient extraction methods are to be used to obtain ...maximum amounts of such beneficial compounds from myrtle. For that reason, this study evaluates the effectiveness of a rapid ultrasound-assisted method (UAE) to extract anthocyanins and phenolic compounds from myrtle berries. The influence of solvent composition, as well as pH, temperature, ultrasound amplitude, cycle and solvent-sample ratio on the total phenolic compounds and anthocyanins content in the extracts obtained were evaluated. The response variables were optimized by means of a Box-Behnken design. It was found that the double interaction of the methanol composition and the cycle, the interaction between methanol composition and temperature, and the interaction between the cycle and solvent-sample ratio were the most influential variables on the extraction of total phenolic compounds (92.8% methanol in water, 0.2 s of cycle, 60 °C and 10:0.5 mL:g). The methanol composition and the interaction between methanol composition and pH were the most influential variables on the extraction of anthocyanins (74.1% methanol in water at pH 7). The methods that have been developed presented high repeatability and intermediate precision (RSD < 5%) and the bioactive compounds show a high recovery with short extraction times. Both methods were used to analyze the composition of the bioactive compounds in myrtle berries collected from different locations in the province of Cadiz (Spain). The results obtained by UAE were compared to those achieved in a previous study where microwave-assisted extraction (MAE) methods were employed. Similar extraction yields were obtained for phenolic compounds and anthocyanins by MAE and UAE under optimal conditions. However, UAE presents the advantage of using milder conditions for the extraction of anthocyanins from myrtle, which makes of this a more suitable method for the extraction of these degradable compounds.
Using the last taxonomic review of chondrichthyans of the world, we selected the species distributed in the north‐western Atlantic Ocean (NWA) and compared it with the available published literature ...related to the class Chondrichthyes in the Venezuelan exclusive economic zone. We also revised information from worldwide databases such as: FAO (NWA‐31 area), GBIF, iSpecies, IUCN and OBIS, as well as available museum collection databases. The taxonomic validity was checked using the Catalogue of Fishes of the California Academy of Sciences and recent references. The past published Venezuelan lists of chondrichthyans combined included nine orders, 30 families and 108 species. The updated list with 12 orders, 36 families and 122 species increased by three new orders, six families, three shark genera, nine shark species (one replacing another species), one chimaera genus, two chimaera species, three batoid genera and six batoid species (two replacing other species). Four holotype specimens (two sharks and two rays) are deposited in Venezuelan Museums. Most of the species have an IUCN conservation status, including four species catalogued as Critically Endangered, six as Endangered and 18 species as Vulnerable. Deep‐sea fisheries, scientific exploration and taxonomic/genetic revisions might add future increments to the Venezuelan chondrichthyan list.
•We report the synthesis of magnetic nanofibrous materials.•Magnetic nanofibrous materials were obtained from the electrospinning technique.•We electrospun nanofibrous materials from CMC/PVA blends ...loaded with SMON.•Nanofibers' diameter decrease as the weight of SMON loaded in blends increases.•Magnetic nanofibrous materials display a novel soft ferromagnetic response.
In this paper, the synthesis of magnetic nanofibrous materials with a soft ferromagnetic response based on magnetite nanoparticles (SMON) loaded to aqueous carboxymethyl-cellulose (CMC)/polyvinyl-alcohol (PVA) polymeric blends is reported. The nanofibrous materials were obtained from the electrospinning of SMON-CMC/PVA blends with different SMON content, applying a constant tension of 15 kV. The synthesized samples were analyzed by transmission electron microscopy, scanning electron microscopy, attenuated total reflectance Fourier transform infrared, Raman and X-Ray photoelectron spectroscopy, as well as static magnetic measuring. Our experimental findings indicate that nanofibers’ diameter decreases as SMON content in the electrospun polymeric blends is increased, since these magnetic nanoparticles diminish the interactions between PVA and CMC molecules, which improves their spinnability. Moreover, the spatial distribution of SMON in the fibers provides to the synthesized nanofibrous materials a novel soft ferromagnetic response at room temperature. This phenomenon is attributed to the formation of nanoparticles’ aggregates that are discretely distributed in the nanofibers.
The phenolic compounds and anthocyanins present in myrtle berries are responsible for its beneficial health properties. In the present study, a new, microwave-assisted extraction for the analysis of ...both phenolic compounds and anthocyanins from myrtle pulp has been developed. Different extraction variables, including methanol composition, pH, temperature, and sample⁻solvent ratio were optimized by applying a Box⁻Behnken design and response surface methodology. Methanol composition and pH were the most influential variables for the total phenolic compounds (58.20% of the solvent in water at pH 2), and methanol composition and temperature for anthocyanins (50.4% of solvent at 50 °C). The methods developed showed high repeatability and intermediate precision (RSD < 5%). Both methods were applied to myrtle berries collected in two different areas of the province of Cadiz (Spain). Hierarchical clustering analysis results show that the concentration of bioactive compounds in myrtle is related to their geographical origin.
The clinical characteristics of patients with relapsing anti-NMDA receptor (NMDAR) encephalitis are not well-defined. In this study, we report the clinical profile and outcome of relapses in a series ...of anti-NMDAR encephalitis.
We did a retrospective review of relapses that occurred in 25 patients with anti-NMDAR encephalitis. Relapses were defined as any new psychiatric or neurologic syndrome, not explained by other causes, which improved after immunotherapy or, less frequently, spontaneously.
A total of 13 relapses were identified in 6 patients. Four of them had several, 2 to 4, relapses. There was a median delay of 2 years (range 0.5 to 13 years) for the first relapse. Median relapse rate was 0.52 relapses/patient-year. Relapse risk was higher in patients who did not receive immunotherapy in the first episode (p = 0.009). Most cases (53%) presented partial syndromes of the typical anti-NMDAR encephalitis. Main symptoms of relapses were speech dysfunction (61%), psychiatric (54%), consciousness-attention disturbance (38%), and seizures (31%). Three relapses (23%) presented with isolated atypical symptoms suggestive of brainstem-cerebellar involvement. An ovarian teratoma was detected at relapse in only 1 patient (17%). Relapses did not add residual deficit to that caused by the first episode.
Relapses in anti-NMDAR encephalitis are common (24%). They may occur many years after the initial episode. Relapses may present with partial aspects or with isolated symptoms of the full-blown syndrome. Immunotherapy at first episode reduces the risk of relapses.
•The anaerobic digestion of tequila vinasses under seasonal conditions was studied.•The proposed start-up procedure attains a stable biofilm in short time periods.•High methane yield was attained ...during the restart-up regardless of biomass detachment.•Prokaryotic communities were monitored by molecular biology analyses.•Stable achaeal and resilient bacterial populations were observed.
This study examines the performance of an anaerobic fixed-film bioreactor under seasonal operating conditions prevailing in medium and small size Tequila factories: start-up, normal operation and particularly, during the restart-up after a long stop and starvation period. The proposed start-up procedure attained a stable biofilm in a rather short period (28days) despite unbalanced COD/N/P ratio and the use of non-acclimated inoculum. The bioreactor was restarted-up after being shut down for 6months during which the inoculum starved. Even when biofilm detachment and bioreactor clogging were detected at the very beginning of restart-up, results show that the bioreactor performed better as higher COD removal and methane yield were attained. CE-SSCP and Q-PCR analyses, conducted on the biofilm prokaryotic communities for each operating condition, confirmed that the high COD removal results after the bioreactor clogging and the severe starvation period were mainly due to the stable archaeal and resilient bacterial populations.
The description of interaction phenomenology between magnetic and luminescent phases in multimodal hybrid nanostructures (MHNs) based on magnetite nanoparticles (mNPs) assembled into templates of a ...luminescent conjugated polymer (LCP) with oxime groups (TUTM) is reported. The MHNs were obtained from the combination of mNPs and TUTM, which were previously synthesized in a separated way, following chemical routes. These MHNs were characterized by transmission electron microscopy techniques, infrared spectroscopy, X-ray photoelectron spectroscopy, fluorescence spectroscopy, as well as magnetic and magneto-optical measuring. The experimental evidence shows the formation of nanoparticle assemblies into the LCP. This is related with the fact that mNPs are immobilized in the TUTM by coordination bonds between oxime groups and Fe
2+
or Fe
3+
cations at their surface. Moreover, these coordination bonds promote the photoinduced electron transfer from lowest unoccupied molecular orbital of TUTM to the unfilled d orbitals of Fe
2+
or Fe
3+
in mNPs that leads to the fluorescence quenching of the LCP. Likewise, they provoke the formation of a new non-fluorescent complex, which gives arise a static quenching of the luminescent phase. In addition, the mNPs assembling induces the exchange coupling among nanoparticles that diminishes the effective anisotropy of the magnetic phase. Moreover, it was observed that the magnetic hardness of the MHNs decreases in the presence of light stimulus. This is related with the photoinduced electrons transfer between phases. Accordingly, the spin of those electrons could contribute to the antiparallel alignment in the magnetic phase, softening the response of MHNs.
Graphical abstract
In this work a computational study of the mechanism of inhibition of cruzain, rhodesain, and cathepsin L cysteine proteases by the dipeptidyl nitroalkene Cbz‐Phe‐Ala‐CH=CH‐NO2 has been carried out by ...means of molecular dynamics simulations with hybrid QM/MM potentials. The free‐energy surfaces confirmed that the inhibition takes place by the formation of a covalent bond between the protein and the β‐carbon atom of the inhibitor. According to the results, the tested inhibitor should be a much more efficient inhibitor of cruzain than of rhodesain, and little activity would be expected against cathepsin L, in total correspondence with the available experimental data. The origin of these differences may lie in the different stabilizing electrostatic interactions established between the inhibitor and the residues of the active site and S2 pocket of these enzymes. These results may be useful for the rational design of new dipeptidyl nitroalkenes with higher and more selective inhibitory activity against cysteine proteases.
Taking control: A computational study of the mechanism of inhibition of three cysteine proteases by the dipeptidyl nitroalkene Cbz‐Phe‐Ala‐CH=CH‐NO2 shows that the inhibition takes place by the formation of a covalent bond between the protein and the Cβ of the inhibitor (see figure). The inhibitory activity of the dipeptidyl nitroalkene is dependent on the nature of the cysteine protease. The results may be useful for the rational design of more efficient and selective dipeptidyl nitroalkenes inhibitors against cysteine proteases.
Abstract
Jets (fast collimated outflows) are claimed to be the main shaping agent of the most asymmetric planetary nebulae (PNs), as they impinge on the circumstellar material at late stages of the ...asymptotic giant branch phase. The first jet detected in a PN was that of NGC 2392, yet there is no available image because of its low surface brightness contrast with the bright nebular emission. Here we take advantage of the tomographic capabilities of Gran Telescopio de Canarias Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía high-dispersion integral field spectroscopic observations of the jet in NGC 2392 to gain unprecedented details of its morphology and kinematics. The jet of NGC 2392 is found to emanate from the central star, break through the walls of the inner shell of this iconic PN and extend outside the nebula’s outermost regions with an S-shaped morphology suggestive of precession. At odds with the fossil jets found in mature PNs, the jet in NGC 2392 is currently being collimated and launched. The high nebular excitation of NGC 2392, which implies an He
++
/He ionization fraction too high to be attributed to the known effective temperature of the star, has been proposed in the past to hint at the presence of a hot white dwarf companion. In conjunction with the hard X-ray emission from the central star, the present-day jet collimation would support the presence of such a double-degenerate system where one component undergoes accretion from a remnant circumbinary disk of the common envelope phase.
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