Arsenic, a metalloid and naturally occurring element, is one of the most abundant elements in the earth's crust. Water is contaminated by arsenic through natural sources (underground water, minerals ...and geothermal processes) and anthropogenic sources such as mining, industrial processes, and the production and use of pesticides. Humans are exposed to arsenic mainly by drinking contaminated water, and secondarily through inhalation and skin contact. Arsenic exposure is associated with the development of vascular disease, including stroke, ischemic heart disease and peripheral vascular disease. Also, arsenic increases the risk of tumors of bladder, lungs, kidneys and liver, according to the International Agency for Research on Cancer and the Food and Drug Administration. Once ingested, an estimated 70–90% of inorganic arsenic is absorbed by the gastrointestinal tract and widely distributed through the blood to different organs, primarily to the liver, kidneys, lungs and bladder and secondarily to muscle and nerve tissue. Arsenic accumulates in the organs, especially in the liver. Its excretion mostly takes place through urination. The toxicokinetics of arsenic depends on the duration of exposure, pathway of ingestion, physicochemical characteristics of the compound, and affected biological species. The present review outlines of arsenic toxic effects focusing on different cancer types whit highest prevalence's by exposure to this metalloid and signaling pathways of carcinogenesis.
•Arsenic is a worldwide health problem mainly through drinking water.•Arsenic toxicity it depends on its reduction state.•Toxic effects of arsenic include different types of cancer.•Different arsenic carcinogenesis mechanism has been proposed.
The Collective Thomson scattering technique has been implemented to study the stagnation of a single liner gas-puff. The plasma parameters are determined by theoretically modelling the scattering ...form factor in combination with Bayesian inference to provide the set of the most probable parameters that describe the experimental data. Analysis of the data reveal that incoming flows are able to interpenetrate partially. Estimation of the mean free path shows a gradual transition from a weakly collisional to a collisional regime as the plasma gets to the axis. Furthermore, we find that the ion energy at Formula: see text is Formula: see text and is mostly kinetic in nature and represents Formula: see text of the total energy. This kinetic energy is far greater than the value on axis of Formula: see text which is Formula: see text of the total energy. Energy transfer to the electrons and radiation losses are found to be negligible by this time. A possible explanation for this energy imbalance is the presence of an azimuthal magnetic field larger than Formula: see text that deflect the ions vertically. The uncertainties quoted represent 68% credible intervals.
Overgrowth syndromes are characterized by global or localized disproportionate growth associated with other anomalies, including vascular malformations and neurological and/or visceral disorders. ...CLOVES (Congenital Lipomatous asymmetric Overgrowth of the trunk with lymphatic, capillary, venous, and combined‐type Vascular malformations, Epidermal naevi, Scoliosis/Skeletal and spinal anomalies) is an overgrowth syndrome caused by mosaic activating mutation in gene PIK3CA, which gives rise to abnormal PI3K‐AKT‐mTOR pathway activation. These mutations are responsible for the clinical manifestations of the syndrome, which include low‐ and high‐flow vascular malformations, thoracic lipomatous hyperplasia, asymmetric growth, and visceral and neurological disorders. These common anomalies are illustrated with figures from two personal cases. Identification of the clinical and genetic characteristics of CLOVES syndrome is crucial for the differential diagnosis with other overgrowth syndromes, such as Proteus or Klippel–Trenaunay (K–T) syndromes, and for the therapeutic management of the different anomalies. In this context, a new entity comprising different syndromes with phenotypic mutations in PIK3CA has been proposed, designated PIK3CA‐related overgrowth spectrum (PROS), with the aim of facilitating clinical management and establishing appropriate genetic study criteria.
PIK3CA pathway and syndromes. Left asymmetric overgrowth and sandal gap.
For the first time, simultaneous production of hydrogen and nanocarbon
via catalytic decomposition of methane over Ni-loaded mesoporous Ce-MCM-41 catalysts was investigated. The catalytic performance ...of the Ni/Ce-MCM-41 catalysts is very stable and the reaction activity remained almost unchanged during 1400 min steam on time at temperatures 540, 560 and 580 °C, respectively. The methane conversion level over these catalysts reached 60–75% with a 100% selectivity towards hydrogen. TEM observations revealed that most of the Ni particles located on the tip of the carbon nanofibers/nanotubes in the used catalysts, keeping their exposed surface clean during the test and thus remaining active for continuous reaction without obvious deactivation. Two kinds of carbon materials, graphitic carbon (
C
g) as major and amorphous carbon (
C
A) as minor were produced in the reaction, as confirmed by XRD analysis and TEM observations. Carbon nanofibers/nanotubes had an average diameter of approximately 30–50 nm and tens micrometers in length, depending on the reaction temperature, reaction time and Ni particle diameter. Four types of carbon nanofibers/nanotubes were detected and their formations greatly depend on the reaction temperature, time on steam and degree of the interaction between the metallic Ni and support. The respective mechanisms of the formation of nanocarbons were postulated and discussed.
Upper Devonian marine deposits of the Baruunhuurai Terrane in western Mongolia represent island arc settings, which yielded a diverse conodont assemblage of 30 taxa, including species of ...Ancyrognathus (as well as one new species), Icriodus, Mehlina, Polygnathus and Palmatolepis. Biodiversity analysis of Ancyrognathus, Pelekysgnathus, Mehlina and Icriodus shows that the Mongolian conodont assemblage consists of two endemic and few cosmopolitan taxa. Representatives of the otherwise globally distributed genus Pelekysgnathus are absent. An important factor influencing the regional distribution of conodont taxa seems to be the siliciclastic-dominated sedimentation of the Baruunhuurai Terrane during the early Famennian.
•Biostratigraphic range at Hushoot Shiveetiin gol section (western Mongolia) covers Pa. min. minuta to Pa. rhomboidea biozones.•Among an assemblage of 30 conodont taxa, Ancyrognathus minjini n. sp. is newly described.•The early Famennian part of the section is dominated by polygnathid-palmatolepid conodont biofacies.
Abstract
We introduce the Automatic Learning for the Rapid Classification of Events (ALeRCE) broker, an astronomical alert broker designed to provide a rapid and self-consistent classification of ...large etendue telescope alert streams, such as that provided by the Zwicky Transient Facility (ZTF) and, in the future, the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST). ALeRCE is a Chilean-led broker run by an interdisciplinary team of astronomers and engineers working to become intermediaries between survey and follow-up facilities. ALeRCE uses a pipeline that includes the real-time ingestion, aggregation, cross-matching, machine-learning (ML) classification, and visualization of the ZTF alert stream. We use two classifiers: a stamp-based classifier, designed for rapid classification, and a light curve–based classifier, which uses the multiband flux evolution to achieve a more refined classification. We describe in detail our pipeline, data products, tools, and services, which are made public for the community (see
https://alerce.science
). Since we began operating our real-time ML classification of the ZTF alert stream in early 2019, we have grown a large community of active users around the globe. We describe our results to date, including the real-time processing of 1.5 × 10
8
alerts, the stamp classification of 3.4 × 10
7
objects, the light-curve classification of 1.1 × 10
6
objects, the report of 6162 supernova candidates, and different experiments using LSST-like alert streams. Finally, we discuss the challenges ahead in going from a single stream of alerts such as ZTF to a multistream ecosystem dominated by LSST.
To characterize the neuropsychological profile of vascular cognitive impairment (VCI) and vascular dementia (VaD).
The authors examined 170 patients with stroke or TIA at 3 to 6 months after the ...vascular event, and 96 age-matched healthy controls, with detailed neuropsychological and medical-psychiatric assessments, with a majority (66.7%) undergoing MRI brain scans. The subjects were diagnosed as having VaD, VCI, or no cognitive impairment by consensus. The neuropsychological tests were classified into cognitive domains, and composite z-scores adjusted for age and education.
VaD subjects had disturbance in all cognitive domains, with verbal memory, especially retention, being less affected. VCI subjects had similar but less severe disturbance. The domains that best discriminated cognitively impaired from unimpaired patients were abstraction, mental flexibility, information processing speed, and working memory. Cognitive impairment had a significant correlation with deep white matter hyperintensities, but not with volume and number of infarctions, even though the VaD subjects had larger infarct volumes than VCI subjects. The MRI variables did not provide additional discrimination between subgroups.
The cognitive deficits in VaD and VCI are characterized by disturbance of frontal functions, with less verbal memory impairment. VaD and VCI differ in severity but not pattern of disturbance. The brain lesions that best account for these deficits are noninfarct subcortical white matter and gray matter changes due to ischemia. The picture of VaD/VCI presented shows subcortical deficits embellished by cognitive deficits from cortical infarctions.
Nowadays, atom-based quantum sensors are leaving the laboratory towards field applications requiring compact and robust laser systems. Here we describe the realization of a compact laser system for ...atomic gravimetry. Starting with a single diode laser operating at 780 nm and adding only one fiber electro-optical modulator, one acousto-optical modulator and one laser amplifier we produce laser beams at all the frequencies required for a Rb-87 atomic gravimeter. Furthermore, we demonstrate that an atomic fountain configuration can also be implemented with our laser system. The modulated system reported here represents a substantial advance in the simplification of the laser source for transportable atom-based quantum sensors that can be adapted to other sensors such as atomic clocks, accelerometers, gyroscopes or magnetometers with minor modifications.
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