Preclinical changes that precede the onset of symptoms and eventual diagnosis of Alzheimer's disease (AD) are a target for potential preventive interventions. A large body of evidence suggests that ...inflammation is closely associated with AD pathogenesis and may be a promising target pathway for such interventions. However, little is known about the association between systemic inflammation and preclinical AD pathophysiology. We first examined whether the acute-phase protein, alpha-2 macroglobulin (A2M), a major component of the innate immune system, was associated with cerebrospinal fluid (CSF) markers of neuronal injury in preclinical AD and risk of incident AD in the predictors of cognitive decline among normal individuals (BIOCARD) cohort. We find that A2M concentration in blood is significantly associated with CSF concentrations of the neuronal injury markers, tau and phosphorylated tau, and that higher baseline serum A2M concentration is associated with an almost threefold greater risk of progression to clinical symptoms of AD in men. These findings were replicated in the Alzheimer's Disease Neuroimaging (ADNI) study. Then, utilizing a systems level approach combining large multi-tissue gene expression datasets with mass spectrometry-based proteomic analyses of brain tissue, we identified an A2M gene network that includes regulator of calcineurin (RCAN1), an inhibitor of calcineurin, a well-characterized tau phosphatase. A2M gene and protein expression in the brain were significantly associated with gene and protein expression levels of calcineurin. Collectively these novel findings suggest that A2M is associated with preclinical AD, reflects early neuronal injury in the disease course and may be responsive to tau phosphorylation in the brain through the RCAN1-calcineurin pathway.
ABSTRACT
The persistently bright ultracompact neutron star low-mass X-ray binary 4U 1820−30 displays an ∼170 d accretion cycle, evolving between phases of high and low X-ray modes, where the 3–10 keV ...X-ray flux changes by a factor of up to ≈8. The source is generally in a soft X-ray spectral state, but may transition to a harder state in the low X-ray mode. Here, we present new and archival radio observations of 4U 1820−30 during its high and low X-ray modes. For radio observations taken within a low mode, we observed a flat radio spectrum consistent with 4U 1820−30 launching a compact radio jet. However, during the high X-ray modes the compact jet was quenched and the radio spectrum was steep, consistent with optically thin synchrotron emission. The jet emission appeared to transition at an X-ray luminosity of $L_{\rm X (3-10\, keV)} \sim 3.5 \times 10^{37} (D/\rm {7.6\, kpc})^{2}$ erg s−1. We also find that the low-state radio spectrum appeared consistent regardless of X-ray hardness, implying a connection between jet quenching and mass accretion rate in 4U 1820−30, possibly related to the properties of the inner accretion disc or boundary layer.
ABSTRACT
The accretion flow/jet correlation in neutron star (NS) low-mass X-ray binaries (LMXBs) is far less understood when compared to black hole (BH) LMXBs. In this paper we will present the ...results of a dense multiwavelength observational campaign on the NS LMXB 4U 1820-30, including X-ray (NICER, NuSTAR, and AstroSat) and quasi-simultaneous radio (ATCA) observations in 2022. 4U 1820-30 shows a peculiar 170 d super-orbital accretion modulation, during which the system evolves between ‘modes’ of high and low X-ray flux. During our monitoring, the source did not show any transition to a full hard state. X-ray spectra were well described using a disc blackbody, a Comptonization spectrum along with a Fe K emission line at ∼6.6 keV. Our results show that the observed X-ray flux modulation is almost entirely produced by changes in the size of the region providing seed photons for the Comptonization spectrum. This region is large (∼15 km) in the high mode and likely coincides with the whole boundary layer, while it shrinks significantly (≲10 km) in low mode. The electron temperature of the corona and the observed rms variability in the hard X-rays also exhibit a slight increase in low mode. As the source moves from high to low mode, the radio emission due to the jet becomes ∼5 fainter. These radio changes appear not to be strongly connected to the hard-to-soft transitions as in BH systems, while they seem to be connected mostly to variations observed in the boundary layer.
ABSTRACT
All 280 of the statistically complete Palomar sample of nearby (<120 Mpc) galaxies δ > 20° have been observed at 1.5 GHz as part of the LeMMINGs e-MERLIN legacy survey. Here, we present ...Chandra X-ray observations of the nuclei of 213 of these galaxies, including a statistically complete sub-set of 113 galaxies in the declination range 40° <δ < 65°. We observed galaxies of all optical spectral types, including ‘active’ galaxies e.g. low-ionization nuclear emission line regions (LINERs) and Seyferts and ‘inactive’ galaxies like ${\rm H\, \small {II}}$ galaxies and absorption line galaxies (ALG). The X-ray flux limit of our survey is 1.65 × 10−14 erg s−1 cm−2 (0.3−10 keV). We detect X-ray emission coincident within 2 arcsec of the nucleus in 150/213 galaxies, including 13/14 Seyferts, 68/77 LINERs, 13/22 ALGs and 56/100 ${\rm H\, \small {II}}$ galaxies, but cannot completely rule out contamination from non-AGN processes in sources with nuclear luminosities $\lesssim 10^{39}$ erg s−1. We construct an X-ray Luminosity function (XLF) and find that the local galaxy XLF, when including all active galactic nucleus (AGN) types, can be represented as a single power law of slope −0.54 ± 0.06. The Eddington ratio of the Seyferts is usually 2−4 decades higher than that of the LINERs, ALGs, and ${\rm H\, \small {II}}$ galaxies, which are mostly detected with Eddington ratios $\lesssim 10^{-3}$. Using ${\rm O\, \small {III}}$ line measurements and black hole masses from the literature, we show that LINERs, ${\rm H\, \small {II}}$ galaxies and ALGs follow similar correlations to low luminosities, suggesting that some ‘inactive’ galaxies may harbour AGN.
Abstract
We present rapid, multiwavelength photometry of the low-mass X-ray binary Swift J1357.2-0933 during its 2017 outburst. Using several sets of quasi-simultaneous ULTRACAM/NTT (optical), NuSTAR ...(X-ray), XRT/Swift (X-ray), SALT (optical), and ATCA (radio) observations taken during outburst decline, we confirm the frequent optical dipping that has previously been noted both in outburst and in quiescence. We also find: (1) that the dip frequency decreases as the outburst decays, similar to what was seen in the previous outburst, (2) that the dips produce a shape similar to that in binary systems with partial disc occultations, (3) that the source becomes significantly bluer during these dips, indicating an unusual geometry compared to other LMXB dippers, and (4) that dip superposition analysis confirms the lack of an X-ray response to the optical dips. These very unusual properties appear to be unique to Swift J1357.2−0933, and are likely the result of a high binary inclination, as inferred from features such as its very low outburst X-ray luminosity. From this analysis as well as X-ray/optical timing correlations, we suggest a model with multicomponent emission/absorption features with differing colours. This could include the possible presence of a sporadically occulted jet base and a recessed disc. This source still hosts many puzzling features, with consequences for the very faint X-ray transients population.
Abstract
We present high-sensitivity 1.51 GHz e-MERLIN (e-Multi-Element Radio-Linked Interferometer Network) radio images of the nearby galaxy NGC 6217. We resolve the compact radio source at the ...centre of NGC 6217 for the first time, finding a twin-lobed structure with a total linear size of ∼4 arcsec (∼400 pc). The radio source does not have a compact central core, but there is an unresolved hotspot near the outer edge of the southern lobe. Combining our e-MERLIN data with new VLA (Very Large Array) A-Array data and archival multiwavelength data, we explore possible scenarios which might explain this complex radio morphology. We conclude that this radio source is most likely powered by a low-luminosity active galactic nucleus but with a possible important contribution from nuclear star formation. We also investigate the origin of a putative X-ray jet in NGC 6217, previously suggested in the literature. This ‘jet’ consists of three X-ray ‘knots’ in a line, pointed away from the nucleus, with a total size of ∼3 arcmin (∼15 kpc). We find no extended radio emission coincident with the ‘jet’. An additional compact radio source, aligned with the knots but without an X-ray counterpart is detected. We detect infrared/optical sources falling within the X-ray extraction regions of the ‘knots’, but note that these sources could be chance associations due to high source density around the target field and we estimate the probability of three randomly aligned X-ray sources to be 0.3 per cent in this field.
Synopsis
Objectives
Water‐in‐oil emulsions in lipsticks could have the potential to improve moisturizing properties and deliver hydrophilic molecules to the lips. The aims of this work were (i) to ...investigate the effect of emulsifier type (polymer vs. monomer, and saturated vs. unsaturated chain) and concentration on droplet size and (ii) to investigate the effect of wax ratio (carnauba wax, microcrystalline wax, paraffin wax and performalene) and aqueous phase volume on material properties (Young's modulus, point of fracture, elastic modulus and viscous modulus).
Methods
Emulsion formation was achieved using a high shear mixer.
Results
Results showed that the saturated nature of the emulsifier had very little effect on droplet size, neither did the use of an emulsifier with a larger head group (droplet size ~18–25 μm). Polyglycerol polyricinoleate (PGPR) resulted in emulsions with the smallest droplets (~3–5 μm), as expected from previous studies that show that it produces a thick elastic interface. The results also showed that both Young's modulus and point of fracture increase with increasing percentage of carnauba wax (following a power law dependency of 3), but decrease with increasing percentage of microcrystalline wax, suggesting that the carnauba wax is included in the overall wax network formed by the saturated components, whereas the microcrystalline wax forms irregular crystals that disrupt the overall wax crystal network. Young's modulus, elastic modulus and viscous modulus all decrease with increasing aqueous phase volume in the emulsions, although the slope of the decrease in elastic and viscous moduli is dependent on the addition of solid wax, as a result of strengthening the network.
Conclusions
This work suggests the potential use for emulsions in lipstick applications, particularly when PGPR is used as an emulsifier, and with the addition of solid wax, as it increases network strength.
Résumé
Objectifs
Les émulsions eau dans huile dans les rouges à lèvres pourraient avoir le potentiel pour améliorer les propriétés hydratantes et délivrer des molécules hydrophiles aux lèvres. Les objectifs de ce travail étaient: (i) d'étudier l'effet du type d'émulsifiant (polymère vs monomère, et de la chaîne saturée vs. insaturés) et de la concentration sur la taille des gouttelettes, et (ii) d'étudier l'effet du taux de cire (cire de carnauba, la cire microcristalline, de la cire de paraffine et PERFORMALENE) et du volume de la phase aqueuse sur les propriétés du matériau (module de Young, le point de rupture, le module élastique et module visqueux).
Méthodes
la formation d'émulsion a été réalisée en utilisant un mélangeur à cisaillement élevé.
Résultats
Les résultats ont montré que la nature saturée de l'émulsifiant a eu très peu d'effet sur la taille des gouttelettes, pas plus que l'utilisation d'un émulsifiant avec un groupe de tête plus grosse (taille des gouttelettes ~ 18–25 μm). Le polyricinoléate de polyglycérol (PGPR) a conduit à des émulsions des plus petites gouttelettes (~ 3–5 μm), comme prévu à partir d'études antérieures qui montrent que cela produit une interface élastique épaisse. Les résultats ont également montré que le module de Young et le point de fracture augmentent avec un pourcentage croissant de la cire de carnauba (selon à une dépendance en loi de puissance de 3), mais diminuent avec un pourcentage croissant de la cire microcristalline, suggérant que la cire de carnauba est inclus dans l'ensemble du réseau de cire formé par les composants saturés, tandis que la cire microcristalline forme des cristaux irréguliers qui perturbent l'ensemble du réseau. Le module de Young, le module élastique et le module visqueux diminuent avec l'augmentation du volume de la phase aqueuse dans l'émulsion, bien que la pente de la diminution de modules élastiques et visqueux soit fonction de l'addition de cire solide, en conséquence du renforcement du réseau.
Conclusions
Ce travail suggère l'utilisation potentielle des émulsions dans des applications de rouge à lèvres, surtout quand PGPR est utilisée comme émulsifiant, et avec l'ajout de cire solide, car elle augmente la force du réseau.
Target 9 in the National Policy on Biological Diversity elaborates on the prevention of known threatened species extinction, and their conservation status needs to be improved by 2025. Key ...Biodiversity Areas (KBA) is a comprehensive approach to conserving globally threatened species, including herpetofauna and their habitats. A site must meet the thresholds for at least one criterion to qualify as Key Biodiversity Area (KBA). This paper aims to demonstrate threatened herpetofauna information in Perak based on published literature according to International Union for Conservation of Nature (IUCN) classification. A total of 34 papers were accessed starting from 1977 until 2022. Of these, 14 threatened herpetofauna species were identified:
Nanohyla annectens, Cyrtodactylus guakanthanensis, Cyrtodactylus jarakensis, Heosemys grandis, Batagur affinis, Manouria emys, Manouria impressa, Pelochelys cantorii, Cuora amboinensis, Heosemys spinosa, Siebenrockiella crassicollis, Amyda cartilaginea, Pseudocalotes larutensis
, and
Larutia larutensis
. There was only 1.9% (1sp), and 11.4% (13spp) of the total number (166spp) of amphibians (52spp) and reptiles (114spp) were published, respectively. However, coordinates of the exact locations must be gathered to ensure spatial and temporal information can be developed to locate the habitat of threatened species. In short, studies on herpetofauna in Perak is still in need. At least, from this assessment, another step towards identifying KBA in Perak has been initiated and must be continued.
Abstract
Malaysia has adopted two ways of conserving its biodiversity; species-based and landscape-based approaches. However, there are limitations of these approaches that can be addressed via Key ...Biodiversity Areas (KBA). Hence, the aim of the study is to review and compare several current conservation approaches in Malaysia with KBA. Systematic literature search was done using a set of keywords in search engine and visited official government websites to obtain relevant documentations on conservation and biodiversity in Malaysia. Based on the findings, KBA is a holistic approach consisting of several biodiversity elements, criteria and themes that can be put in place, including Important Plant Areas (IPA), Important Bird and Biodiversity Areas (IBA), Important Fungus Areas and Prime Butterfly Areas. This approach has successfully helped many countries such as the Philippines, Indo-Burma hotspot, Uganda, and Canada identify and prioritize important sites for biodiversity conservation. Thus, KBA approach is an alternative approach to support stakeholders in mainstreaming biodiversity conservation approaches in Malaysia for more effective conservation planning in the future. This approach also offers geographic targets for the expansion of protected area coverage and identifies the site for urgent conservation action.
Abstract
The information and status of the avifauna community that resides in Tasik Meranti, Wang Kelian, Taman Negeri Perlis are mostly outdated since the last survey conducted was 20 years ago. ...Therefore, the study aims to update the status and establish a checklist to compare the bird species present within the vicinity of Tasik Meranti, Wang Kelian, Taman Negeri Perlis. The survey was conducted during a short expedition held on 15-18 August 2019. Based on the field observation, a total of 20 species of birds from 14 families were recorded. The recent survey recorded an additional 18 bird species from 8 families, totalling the current inventory of 45 bird species from 24 families. Species from the family Pycnonotidae dominated the site with six species, namely
Pycnonotus finlaysoni, Pycnonotus brunneus, Pycnonotus plumosus, Pycnonotus goiavier, Iole charlottae
and
Pycnonotus simplex.
The high number of species present from the family Pycnonotidae may be due to the availability of food resources. Out of 45 species of birds in the current checklist, three species are listed as near threatened and one species as vulnerable based on the IUCN Red List. Therefore, the result documents the importance of the site for the avifauna community. Therefore, further studies are needed to understand the avifauna population dynamics in Taman Negeri Perlis.
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