Currently, the characteristics of solid-state phase transformation corresponding to octacalcium phosphate (OCP) sintering is still not completely understood. Although it was known that Ca-deficient ...(Ca-def) hydroxyapatite (HA) is usually unstable at high temperature, the thermal stability and sintering behavior of OCP have been rarely reported. The objective of this study is to systematically investigate the thermal stability and sintering behavior of OCP powders by comprehensive characterization techniques including in-situ high temperature X-ray diffraction (XRD), transmission electron microscopy (TEM), differential thermal analysis (DTA) and scanning electron microscopy (SEM). In-situ XRD results showed that the “collapsed OCP”, Ca-def HA and β-tricalcium phosphate (TCP) crystal structures formed by heating OCP at 200–250 °C, 300–600 °C and 800–900 °C, respectively. Furthermore, DTA analysis revealed that the peak temperatures of the phase transitions of OCP to Ca-def HA and Ca-def HA to β-TCP were ∼170 °C and ∼720 °C, respectively. SEM examination indicated that a large number of pores were introduced during sintering OCP powders due to the release of structurally contained water at 200–250 °C. Therefore, a porous β-TCP ceramic can be directly prepared by sintering OCP powders at 900 °C. This phase transition induced foaming method may be extended for preparing porous bioceramics by sintering calcium phosphate phases as long as they contain crystalline water, which could provide guidelines for better utilizing the phase transformations of calcium phosphate to produce special bioceramics for biomedical applications.
•“Collapsed octacalcium phosphate (OCP)” formed by heating OCP at 200–250 °C.•Ca-deficient (Ca-def) hydroxyapatite (HA) formed by heating OCP at 300–600 °C.•β-tricalcium phosphate (TCP) formed by heating OCP at 800–900 °C.•Peak temperatures of OCP to Ca-def HA and Ca-def HA to β-TCP were ∼170 °C and ∼720 °C.•Many pores were introduced during sintering OCP due to crystalline water release.
A low‐profile circularly polarized folded reflectarray antenna (CPFRA) with linearly polarized (LP) feed antenna is presented in this article. Polarizing grid usually used as the subreflector of ...traditional FRA is replaced by a polarization‐sensitive frequency selective surface (FSS) in the CPFRA design. The polarization‐sensitive FSS is designed to convert the LP incidence into the CP wave within its passband while reflecting the orthogonal LP incident wave over its operating frequency band. A CPFRA prototype has been proposed and validated for Ka band satellite communications uplinks in this article. The maximum measured antenna gain of 26.0 dBic is achieved at 29.75 GHz with the corresponding antenna aperture efficiency of 40%. Beam scanning property has been achieved by the CPFRA with the mechanical movement of feed horn antenna. All the measured axial ratios (ARs) of the CPFRA are lower than 3 dB in the frequency range from 29 to 30.25 GHz. Meanwhile, the measured antenna gain variation with different beam scanning angles is less than 1 dB from 29.25 to 31 GHz.
This paper reports a high-performance 90° waveguide hybrid coupler working in the full
W
-band. We demonstrate an 8-branch hybrid which features the low amplitude imbalance over a wide band by first ...increasing the waveguide height inwards and second introducing waveguide height discontinuity sections on the other inner side. Such a compact and robust waveguide hybrid coupler can be implemented in a split-block easily by current computer numerical control milling technology. The measured results show that the reflection and isolation are better than 16 dB, the amplitude imbalance is less than 0.8 dB, and the phase difference is within 90–4.25°/+ 2.38°, which are close to the simulations in most of the
W
-band.
In this letter, the concept of high-gain multifunctional antenna based on folded reflectarray antenna (FRA) and polarization-sensitive frequency selective surface (FSS) is proposed. Antenna with ...multiple functions can be realized by using a polarization-sensitive FSS as the subreflector of FRA instead of the traditional polarizing grid. To validate this concept, a high-gain filtering antenna designed at Ka -band is presented as a design example. Good filtering performance of the antenna has been achieved due to the frequency selective characteristics of FSS. Besides, the relationship between the focal-length-to-diameter ( F/D ) ratio of FRA and the size of FSS element has also been discussed.
Timely diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is a prerequisite for treatment and prevention. The serology characteristics and complement diagnosis value ...of the antibody test to RNA test need to be demonstrated.
Serial sera of 80 patients with PCR-confirmed coronavirus disease 2019 (COVID-19) were collected at the First Affiliated Hospital of Zhejiang University, Hangzhou, China. Total antibody (Ab), IgM and IgG antibodies against SARS-CoV-2 were detected, and the antibody dynamics during the infection were described.
The seroconversion rates for Ab, IgM and IgG were 98.8%, 93.8% and 93.8%, respectively. The first detectible serology marker was Ab, followed by IgM and IgG, with a median seroconversion time of 15, 18 and 20 days post exposure (d.p.e.) or 9, 10 and 12 days post onset (d.p.o.), respectively. The antibody levels increased rapidly beginning at 6 d.p.o. and were accompanied by a decline in viral load. For patients in the early stage of illness (0-7 d.p.o), Ab showed the highest sensitivity (64.1%) compared with IgM and IgG (33.3% for both; p<0.001). The sensitivities of Ab, IgM and IgG increased to 100%, 96.7% and 93.3%, respectively, 2 weeks later. When the same antibody type was detected, no significant difference was observed between enzyme-linked immunosorbent assays and other forms of immunoassays.
A typical acute antibody response is induced during SARS-CoV-2 infection. Serology testing provides an important complement to RNA testing in the later stages of illness for pathogenic-specific diagnosis and helpful information to evaluate the adapted immunity status of patients.
Intrauterine adhesion (IUA) is a major health problem that causes infertility, menstrual irregularities, and recurrent pregnancy losses in women. Unfortunately, treatments for IUA are limited, and ...there are currently no effective strategies for preventing IUA recurrence. In this review, we introduced the role of Hippo signaling in the normal endometrium and IUA and described the mechanisms by which the Hippo pathway integrates with the Wnt and transforming growth factor-β (TGF-β) signaling pathways to form an intricate network governing the development of fibrosis.
Original research articles in English that were published until July 2017 were collected from the PubMed database.
Literature search was conducted using the search terms "endometrial fibrosis OR fibrosis AND or OR intrauterine adhesion OR Asherman syndrome OR IUA," "Hippo AND or OR Hippo/TAZ," "TGF-β," and "Wnt." Related original research articles were included in the comprehensive analysis.
Endometrial fibrosis is recognized as a key pathological event in the development of IUA, which is characterized by epithelial/fibroblast-myofibroblast transition. Myofibroblasts play crucial roles in the pathogenesis of fibrous scarring, and myofibroblast differentiation can be triggered by multiple signaling pathways. Hippo signaling is a critical regulator of the epithelial/fibroblast-myofibroblast transition and α-smooth muscle actin, which exhibits a specific spatiotemporal expression in the endometrium.
Hippo signaling plays a critical role in fibrous diseases and participates in cross talks with Wnt and TGF-β signaling. Our findings not only contributed to knowledge on the pathogenesis of endometrial fibrosis, but can also serve as a useful resource for developing specific molecular inhibitors for IUA treatment and prevention.
Background & Aims This study aimed at investigating mutations in the hepatitis B surface protein (HBsAg) in occult hepatitis B virus (HBV) infection (OBI) and their influence on viral antigenicity ...and phenotype. Methods The characteristics of 61 carriers with OBI (OBI group), 153 HBsAg(+) carriers with serum HBsAg ⩽100 IU/ml (HBsAg-L group) and 54 carriers with serum HBsAg >100 IU/ml (HBsAg-H group) from 38,499 blood donors were investigated. Mutations in the major hydrophilic region (MHR) of the viral sequences were determined. Thirteen representative MHR mutations observed in OBI sequences were antigenically characterized with a panel of monoclonal antibodies (MAbs) and commercial HBsAg immunoassays and functionally characterized in HuH7 cells and hydrodynamically injected mice. Results Of 61 OBI sequences, 34 (55.7%) harbored MHR mutations, which was significantly higher than the frequency in either the HBsAg-L (34.0%, p = 0.003) or the HBsAg-H group (17.1%, p <0.001). Alterations in antigenicity induced by the 13 representative MHR mutations identified in the OBI group were assessed by reacting recombinant HBV mutants with 30 different MAbs targeting various epitopes. Four out of the 13 mutations (C124R, C124Y, K141E, and D144A) strongly decreased the analytical sensitivity of seven commercial HBsAg immunoassays, and 10 (G119R, C124Y, I126S, Q129R, S136P, C139R, T140I, K141E, D144A, and G145R) significantly impaired virion and/or S protein secretion in both HuH7 cells and mice. Conclusions MHR mutations alter antigenicity and impair virion secretion, both of which may contribute to HBsAg detection failure in individuals with OBI.
Linked ContentThis article is linked to Zheng et al and Liu et al papers. To view these articles visit https://doi.org/10.1111/apt.14929 and https://doi.org/10.1111/apt.15048.
Organic-rich black shale of the Upper Yangtze Basin from the Late Ordovician and Early Silurian is considered an excellent source rock in South China. The formation and preservation conditions of ...this resource are revealed by its geochemical characteristics in this study. Geochemical indices, including redox indices (V/(V + Ni), V/Cr, V/Sc, and Ni/Co) and primary productivity indices (P/Ti and Ba/Al), and paleoclimate, clastic flux and sedimentary rate analyses are presented to investigate the accumulation mechanism of organic matter. Redox indices suggest that a stagnant, anoxic environment predominated in the Upper Yangtze Basin during accumulation of Wufeng and Longmaxi formations. In contrast, ventilated and oxygenated marine conditions pervaded the Upper Yangtze Basin during deposition of Linxiang and Guanyinqiao formations. The concentrations of V and U demonstrate that accumulation of organic matter was mainly controlled by redox conditions. Besides, such factors as clastic fluxes, fresh water inflows or a mixed deposition with a rapid sedimentary rate cannot be ignored due to their influences on organic matter enrichment and preservation. However, weak co-variance relationship of TOC content and productivity proxies, including P/Ti and Ba/Al, demonstrates that the accumulation of organic matter was not controlled by primary productivity. Results of the present study suggest a depositional model that stresses the importance of tectonic movements and glacial events on the accumulation and preservation of organic matter. The model shows that the Upper Yangtze Basin was a semi-restricted basin system influenced by the isolation of Xuefeng, but also it implies that oxygen-depleted bottom water of the basin favored the accumulation and preservation of sedimentary organic matter, resulting in the formation of organic-rich black shale.
•A stratified water column and dysoxic to anoxic bottom water conditions played a dominant role in the preservation of organic matter.•A model of the black shale's formation is established.•Tectonic movement and glacial dominate stagnation and stratification of seawater.
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