Abstract
We report on analysis of observations of the bright transient X-ray pulsar Swift J0243.6+6124 obtained during its 2017-2018 giant outburst with Insight-HXMT, NuSTAR, and Swift observatories. ...We focus on the discovery of a sharp state transition of the timing and spectral properties of the source at super-Eddington accretion rates, which we associate with the transition of the accretion disk to a radiation pressure dominated (RPD) state, the first ever directly observed for magnetized neutron star. This transition occurs at slightly higher luminosity compared to already reported transition of the source from sub- to super-critical accretion regime associate with onset of an accretion column. We argue that this scenario can only be realized for comparatively weakly magnetized neutron star, not dissimilar to other ultra-luminous X-ray pulsars (ULPs), which accrete at similar rates. Further evidence for this conclusion is provided by the non-detection of the transition to the propeller state in quiescence which strongly implies compact magnetosphere and thus rules out magnetar-like fields.
Abstract Our aim was to differentiate IgG4-related sialadenitis, primary Sjögren syndrome, and chronic obstructive submandibular sialadenitis by analysing clinical, radiographic, and pathological ...features. Fifty-five patients, 50, and 50 were enrolled, respectively and their baseline characteristics and serological, sialographic, and pathological findings compared. The male:female ratio for IgG4-related sialadenitis was 1:1.2 for primary Sjögren syndrome 1:15.7, and for chronic obstructive submandibular sialadenitis1:0.92. Numbers with enlarged salivary glands were 55, 16, and 50; with xerostomia 26, 48, and 0; with a history of allergy 26, 4, and 6, and with coexisting systemic disease 12, 19, and 0 (p = 0.14). Mean (SD) serum IgG4 concentrations were 109.1 (97.9), 4.9. (1.9) g/L, and 5.3 (1.6) g/L, p < 0.001 in all cases. Sialography showed enlargement of the gland, dilatation of the duct, and slightly decreased secretory function in IgG4-related disease; obvious sialectasia and decreased secretory function in Sjögren syndrome; and dilatation of Wharton’s duct and filling defects in obstructive sialadenitis. Histopathological examination showed lymphoplasmacytic infiltration with storiform fibrosis, lymphoplasmacytic inflammation and lymphoepithelial lesions, and dilatation of the duct with epithelial metaplasia in the three groups, respectively. The number of IgG4-positive plasma cells was 123 (45)/HPF, 8 (3)/HPF, and 5 (4)/HPF, while the IgG4-/IgG-positive cell ratio was 71.7 (13.9)%, 4.6 (2.5)%, 18.9 (19.7)%, respectively (p < 0.001). The three conditions have different clinical, radiographic, and pathological features that provide important clues to the differential diagnosis. Serological and histological tests are important, and comprehensive consideration is necessary.
Substrate channeling is a process of transferring the product of one enzyme to an adjacent cascade enzyme or cell without complete mixing with the bulk phase. Such phenomena can occur in vivo, in ...vitro, or ex vivo. Enzyme–enzyme or enzyme–cell complexes may be static or transient. In addition to enhanced reaction rates through substrate channeling in complexes, numerous potential benefits of such complexes are protection of unstable substrates, circumvention of unfavorable equilibrium and kinetics imposed, forestallment of substrate competition among different pathways, regulation of metabolic fluxes, mitigation of toxic metabolite inhibition, and so on. Here we review numerous examples of natural and synthetic complexes featuring substrate channeling. Constructing synthetic in vivo, in vitro or ex vivo complexes for substrate channeling would have great biotechnological potentials in metabolic engineering, multi-enzyme-mediated biocatalysis, and cell-free synthetic pathway biotransformation (SyPaB).
Particle size, composition and optical properties were measured at a regional atmosphere background station in the Yangtze River Delta (YRD) to understand the formation and evolution of haze-fog ...episodes in Jan. 2013. The peak of particle number size distribution was in the size range of 80–100 nm during the measurements. PM1 mass concentration contributed 84% to the total particle mass (PM10). Based on visibility and ambient relative humidity, three types of weather conditions (i.e., clear, haze and fog) were classified in this study. The extinction coefficients of PM1 and PM10 under dry conditions were simulated by the Mie model. Under dry conditions, PM1 was found to contribute approximately 91% to the light extinction coefficient of PM10. However, the PM1 with the assumption of dry state was found to contribute approximately 85% to the ambient extinction coefficient of PM10 during clear conditions, 58% during haze conditions and approximately 41% during fog conditions. The variation of the dry PM1 contribution was related to the water uptake of particles under different relative humidity conditions.
A severe haze-fog event on Jan. 14–17 was discussed in more detail as a case study. Two episodes were chosen to show that nitrate and organics dominated the aerosol component during the severe haze-fog episode and were related to secondary aerosol formation and air mass origin. Nitrate played a more dominant role than sulfate in heavy haze formation in the YRD region, which was different from the North China Plain region.
•Particle number size distribution characteristic during haze-fog episode.•Submicron aerosol influence on light extinction coefficient is evaluated.•Secondary aerosol formation controlling haze-fog episode.•The effect of air mass origin on haze-fog formation episode.
Based on in situ and ground‐based observations, a new type of “polar cap hot patch” has been identified that is different from the classical polar cap enhanced density structure (cold patches). ...Comparing with the classical polar cap patches, which are transported from the dayside sunlit region with dense and cold plasma, the polar cap hot patches are associated with particle precipitations (therefore field‐aligned currents), ion upflows, and flow shears. The hot patches may have the same order of density enhancement as classical patches in the topside ionosphere, suggesting that the hot patches may be produced by transported photoionization plasma into flow channels. Within the flow channels, the hot patches have low‐energy particle precipitation and/or ion upflows associated with field‐aligned currents and flow shears. Corresponding Global Navigation Satellite System (GNSS) signal scintillation measurements indicate that hot patches may produce slightly stronger radio signal scintillation in the polar cap region than classical patches. A new type of polar cap patches, “polar cap hot patches,” is identified to differentiate enhanced density structures from classical patches. Hot patches are associated with particle precipitations, ion upflows, field‐aligned currents, and shear flows in the polar cap. Hot patches may lead to slightly stronger ionospheric scintillations of GNSS signals in the polar cap region than classical patches.
Key Points
A new type of polar cap patches, “polar cap hot patches,” is identified to differentiate enhanced density structures from classical patches
Hot patches are associated with particle precipitations, ion upflows, field‐aligned currents, and shear flows in the polar cap
Hot patches may lead to slightly stronger ionospheric scintillations of GNSS signals in the polar cap region than classical patches
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