ABSTRACT
The temporal variation of solar coronal rotation appears to be very complex and its relevance to the 11-year solar activity cycle is still unclear. Using the modified coronal index for the ...time interval from 1939 January 1–2019 May 31, the systematic regularities of solar coronal rotation are investigated. Our main findings are as follows. (1) From a global point of view, the synodic coronal rotation period with a value of 27.5 days is the only significant period at periodic scales shorter than 64 days. (2) The coronal rotation period exhibits an obvious decreasing trend during the time interval considered, implying that the solar corona accelerates its global rotation rate in the long run. (3) Significant periods of 3.25, 6.13, 9.53 and 11.13 years exist in coronal rotation, providing evidence that coronal rotation should be connected with the quasi-biennial oscillation, the 11-year solar cycle and the 22-year Hale cycle (or magnetic activity reversal). (4) The phase relationship between the coronal rotation period and solar magnetic activity is not only time-dependent but also frequency-dependent. For a small range around the 11-year cycle band, there is a systematic trend in phase and a small mismatch in this band causes the phase to drift. The possible mechanism for the above analysis results is discussed.
Early diagnosis and treatment of herpes simplex encephalitis are crucial to reduce morbidity and mortality. Our aim was to investigate the role of 3D pseudocontinuous arterial spin-labeling in herpes ...simplex encephalitis.
From 2014 to 2019, seventeen consecutive patients with herpes simplex encephalitis and 15 healthy volunteers were recruited in the study. Conventional MR imaging and 3D pseudocontinuous arterial spin-labeling were performed in all subjects. According to the disease duration, the lesions were classified into 3 groups, including acute, subacute, and chronic stages, respectively. Clinical, neuroradiologic, and follow-up features were studied. The normalized lesion/normal tissue CBF values of lesions at different stages were measured and compared with those in the control group, respectively.
Compared with the control group, herpes simplex encephalitis demonstrated hyperperfusion in 11 acute cases and 6 subacute cases and hypoperfusion in 6 chronic cases. The mean normalized lesion/normal tissue CBF values of the lesions were 2.68 ± 0.54 in the acute stage, 2.42 ± 0.52 in the subacute stage, and 0.87 ± 0.30 in the chronic stage, respectively. The mean normalized lesion/normal tissue CBF values of acute and subacute lesions were significantly higher than those of the control group (1.33 ± 0.08;
< .001, respectively), while the mean normalized lesion/normal tissue CBF values of chronic lesions were lower than those of the control group (
< .05). Gradual perfusion reduction on serial 3D pseudocontinuous arterial spin-labeling was observed in herpes simplex encephalitis after effective therapy.
Conventional MR imaging remains most helpful in the diagnosis of herpes simplex encephalitis, while 3D pseudocontinuous arterial spin-labeling could be an adjunctive technique by providing dynamic CBF features at different stages in herpes simplex encephalitis.
Sandwich type Al1060/Al6061-0.5SiC/Al1060 laminates were fabricated by hot roll bonding and then subjected to heat treatment. The microstructure, texture and mechanical properties of the laminates ...were investigated. The inhomogeneity of microstructure throughout the thickness of 1060 Al layer was present in the as-rolled laminates. After heat treatment, the Al6061-0.5SiC composite layer was in a partially recrystallized condition. Some grains were subdivided by low-angle grain boundaries (LAGBs), and the fraction of LAGBs increased with increasing rolling reduction. The amount of Mg2Si precipitates increased with increasing rolling reduction. The Al6061-0.5SiC composite was characterized by the α fiber and β fiber after hot rolling. After heat treatment, the texture in Al6061-0.5SiC composite was dominated by Goss and R component. The tensile strength of the as-rolled laminates increased with increasing rolling reduction, while the elongation first increased and then decreased. The heat treatment could effectively improve the tensile properties of the Al1060/Al6061-0.5SiC/Al1060 laminates.
In the present work, cerium iron phosphate glasses were studied to examine the effect of the CeO
2 composition on the structure of the iron phosphate glasses system. Cerium iron phosphate samples ...with the compositions, I:
xCeO
2
(40
−
x)Fe
2O
3
60P
2O
5 and II:
xCeO
2
(100
−
x)(40Fe
2O
3
60P
2O
5) (
x
=
0–30
mol%) have been prepared. The structure of glasses has been studied using X-ray diffraction (XRD), Raman spectrum, Fourier transform infrared spectrum (FT-IR) and differential thermal analysis (DTA), especially focusing on the structure dependence on the CeO
2 content. The glass formation occurs at series I; at series II, the crystalline phases are detected in the samples. The Q
1 groups are the predominant structural units in glasses with the cerium-free and 10
mol% CeO
2 content. With increasing CeO
2 content in glass compositions, the P
O
P network get extensively depolymerised, resulting in the systematic conversion of Q
1 to Q
2 structural units. The Q
0 units can be detected in the all glasses compositions. The glass transition temperature (
T
g) linearly increase with the addition of CeO
2 content, indicating an increase in thermal stability tendency with increasing CeO
2 content. The change of
T
g is consistent with structural modification of glass.
To evaluate the effect of aging on pulmonary vessels based on computed tomography (CT) quantification and analyse the correlation between quantitative pulmonary vascular volume and pulmonary function ...during aging.
A total of 330 healthy adult volunteers, including 161 men (53 aged 20–39 years, 61 aged 40–59 years, and 47 aged ≥60 years) and 169 women (53 aged 20–39 years, 63 aged 40–59 years, and 53 aged ≥60 years) were recruited in this study. AVIEW software was used to quantitatively measure pulmonary vascular volume, including pulmonary total blood vessel volume (TBV) and small blood vessel volume with a cross-sectional area of <5 mm2 (BV5). Pulmonary vascular volume parameters were standardised using the ratio of vascular volume to the body surface area (BSA; TBV/BSA and BV5/BSA). Subsequently, the effect of aging on the pulmonary vessels was analysed.
The pulmonary vascular volume parameters TBV/BSA and BV5/BSA of the whole lung, right lung, and left lung decreased significantly with increasing age (p<0.05). Additionally, TBV/BSA and BV5/BSA of the whole lung were higher in men than in women. The declining trend of pulmonary vascular volume was consistent in men and women and increased with age.
The pulmonary vascular volume parameters, TBV/BSA and BV5/BSA, decreased with age and were weakly positively correlated with pulmonary function.
•Aging affects the pulmonary vascular structure.•With the increase in age, the pulmonary vascular volume decreased significantly.•The declining trend of the pulmonary vascular volume was consistent in both sexes.•The pulmonary vascular volume was weakly correlated with pulmonary function.
The direct shear tests of different dry density and moisture content samples at different temperatures of the frozen soil in the Qinghai-Tibet Railway embankment between Tanggula South and Anduo ...section were carried out to analyze the influence rules of each experimental factor on the mechanical properties of frozen soil during the freeze-thaw process. The results show the following. (1) When the frozen soil temperature is below 0°C and continues to drop during the freezing and thawing process, each sample shows the law of a significant increase in cohesion and a slight decrease in the internal friction angle. In the meantime, the cohesion obtained during the thawing process of the sample at the same temperature point is higher than that obtained during the freezing process. In contrast, the internal friction angles exhibit an opposite law, where the internal friction angle during the melting process is lower than the internal friction angle during the freezing process. After freezing-thawing action, it deserves to be mentioned that the cohesion increases slightly while the internal friction angles present a slight decrease trend compared to the initial state. (2) With the decrease in temperature and the gradual increase in cohesion, the temperature curve can be divided into a fast-growing section from 0 to −2°C, a slow-growing section from −2 to −8°C, and a second fast-growing section from −8 to −10°C owing to the combined effect of the pressure-thawing action and ice-water phase change. In addition, the rate of decrease in the internal friction angle also shows a similar pattern. (3) The cohesion and the internal friction angle of samples both tend to increase first and then decrease with the rise of the initial moisture content, and the critical initial moisture content is near the optimal moisture content of 15%. (4) Both the cohesion and the internal friction angle of the samples increase with dry density growth. The growth rate of cohesion will gradually increase as the temperature decreases. Moreover, the growth rate of cohesion of low dry density samples is more susceptible to temperature, while the internal friction angle growth rate is not affected by temperature.
Periodically ordered arrays of vertically aligned Si nanowires (Si NWs) are successfully fabricated by nanosphere lithography combined with metal-assisted chemical etching. By adjusting the etching ...time, both the nanowires’ diameter and length can be well controlled. The conductive properties of such Si NWs and particularly their size dependence are investigated by conductive atomic force microscopy (CAFM) on individual nanowires. The results indicate that the conductance of Si NWs is greatly relevant to their diameter and length. Si NWs with smaller diameters and shorter lengths exhibit better conductive properties. Together with the I–V curve characterization, a possible mechanism is supposed with the viewpoint of size-dependent Schottky barrier height, which is further verified by the electrostatic force microscopy (EFM) measurements. This study also suggests that CAFM can act as an effective means to explore the size (or other parameters) dependence of conductive properties on individual nanostructures, which should be essential for both fabrication optimization and potential applications of nanostructures.
Abstract Embryo implantation involves invasion of placental extravillous trophoblast cell (EVTs) into the uterus. Hyperactive EVT invasion occurs in hydatidiform moles and choriocarcinomas. We have ...previously demonstrated that the 20S proteasome is involved in mouse embryo implantation and its action is mediated via regulating the expression and activities of matrix metalloproteinase (MMP)-2 and MMP-9 in the EVTs. Our objective was to investigate whether low molecular mass polypeptide-2 (LMP2), a beta subunit of the 20S proteasome, is involved in the regulation of human trophoblast invasion. Normal human placentas or placentas from hydatidiform mole patients were collected and the expression of LMP2 in different cell types including trophoblastic column (TC), cytotrophoblast cells (CTB) and syncytiotrophoblast (STB) under different pathological states were studied by immunohistochemical analysis. Furthermore, the effect of LMP2 or proteasome on cell invasion was measured by using RNAi and inhibitors in a Matrigel invasion assay system in HTR-8/SVneo cells, a human invasive extravillous trophoblast cell line. Changes in the invasion-related molecules including MMP-2 and MMP-9 were also examined by using real time PCR and gelatin zymography. We demonstrated that the expression of LMP2 in TC of partial hydatidiform mole and complete hydatidiform mole, is higher than that in TC of normal human placentas. Besides, LMP2 knockdown significantly attenuated IL-1β-induced cell invasion in vitro , a response readily induced by proteasome inhibitors. In summary, over-expression of the 20S proteasome β-subunit LMP2 in trophoblast cells of hydatidiform moles may contribute to its highly invasive phenotype.
Abstract
Single-layer FeSe films grown on the SrTiO
3
substrate (FeSe/STO) have attracted much attention because of their possible record-high superconducting critical temperature (T
c
) and distinct ...electronic structures. However, it has been under debate on how high its T
c
can really reach due to the inconsistency of the results from different measurements. Here we report spectroscopic evidence of superconductivity pairing at 83 K in single-layer FeSe/STO films. By preparing high-quality single-layer FeSe/STO films, we observe strong superconductivity-induced Bogoliubov back-bending bands that extend to rather high binding energy ~ 100 meV by high-resolution angle-resolved photoemission measurements. They provide a new definitive benchmark of superconductivity pairing that is directly observed up to 83 K. Moreover, we find that the pairing state can be further divided into two temperature regions. These results indicate that either T
c
as high as 83 K is achievable, or there is a pseudogap formation from superconductivity fluctuation in single-layer FeSe/STO films.
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