286 research outputs found
N,NâČ-Bis(2-quinolylcarbonÂyl)hydrazine
The title compound, C20H14N4O2, crystallizes in the orthoÂrhomÂbic system with a crystallographic twofold axis through the NâN bond. The molÂecule is non-planar and the dihedral angle between two amide groups is 74.9â
(2)°. An intraÂmolecular NâHâŻN hydrogen bond is present. In the crystal, the molÂecules are packed in chains running along the c axis through interÂmolecular NâHâŻO hydrogen bonds. These chains are further stabilized by interÂmolecular CâHâŻO hydrogen bonds and CâHâŻÏ interÂactions leading to the formation of a three-dimensional network
Investigating characteristics of the long-term settlement of railway embankments in warm permafrost areas
Introduction: The embankment in the permafrost zone of the QinghaiâTibet Railway (QTR) faces the problem of permafrost degradation, especially in the warm and ice-rich permafrost areas. The settlement deformation of the embankment is more serious in these areas.Methods: This study systematically investigates the settlement deformation characteristics during 16 operational years of three types of typical roadbed structures. The traditional embankment (TE), U-shaped crushed-rock embankment (UCRE), and crushed-rock revetment embankment (CRRE) are the roadbed structures. The long-term monitoring ground temperature and deformation data of the embankment section along the QTR in warm permafrost areas from 2005 to 2020 are utilized in analysis.Results and Discussion: This study focuses on the influence law of the roadbed structure form, shadyâsunny slope effect, and temperature field change on the settlement of the roadbed. The results indicated that the two types of the crushed-rock embankment (CRE) of the long-term cumulative settlement are less than 50% of the cumulative settlement of the TE, and the impact on controlling the settlement is significant. The annual settlements of the three types of embankment structures are related to the artificial permafrost table (APT) and influenced by cyclical climate change at the regional scale. The annual growth rate of the settlement at the left and right shoulders of the UCRE as a result of the effect of the shadyâsunny slope does not vary considerably as the number of operational years increases. The impact of the shadyâsunny slope on the CRRE for the various settlements before 2008 was negligible. After 2008, the thermal disturbance to the embankment temperature field induced by the preconstruction and the effect of shadyâsunny slopes decreased gradually as the number of operational years increased. In some years of operation, a thawed interlayer in the TE and CRRE greatly affected the embankment settlement acceleration. The settlement growth rate of the TE is related to the decline of the artificial permafrost table (APT). During the operational years, there was no thawed interlayer in the UCRE. The development of the settlement rate is unaffected by the temperature field for either the left or right embankment shoulder
Brief Communication Ophthalmic plastic and orbital surgery in Taiwan
Abstract We describe in this paper the current status of ophthalmic plastic and orbital surgery in Taiwan. Data were collected from the Bureau of National Health Insurance of Taiwan, the Bulletin of the Taiwan Ophthalmic Plastic and Reconstructive Society, and the Statistics Yearbook of Practicing Physicians and Health Care Organizations in Taiwan by the Taiwan Medical Association. We ascertained that 94 ophthalmologists were oculoplastic surgeons and accounted for 5.8% of 1621 ophthalmologists in Taiwan. They had their fellowship training abroad (most ophthalmologists trained in the United States of America) or in Taiwan. All ophthalmologists were well trained and capable of performing major oculoplastic surgeries. The payment rates by our National Health Insurance for oculoplastic and orbital surgeries are relatively low, compared to Medicare payments in the United States. Ophthalmologists should promote the concept that oculoplastic surgeons specialize in periorbital plastic and aesthetic surgeries. However, general ophthalmologists should receive more educational courses on oculoplastic and cosmetic surgery
Role of Macrophage Migration Inhibitory Factor in the Proliferation of Smooth Muscle Cell in Pulmonary Hypertension
Pulmonary hypertension (PH) contributes to the mortality of
patients with lung and heart diseases. However, the underlying
mechanism has not been completely elucidated. Accumulating
evidence suggests that inflammatory response may be involved in
the pathogenesis of PH. Macrophage migration inhibitory factor
(MIF) is a critical upstream inflammatory mediator which promotes
a broad range of pathophysiological processes. The aim of the
study was to investigate the role of MIF in the pulmonary vascular
remodeling of hypoxia-induced PH. We found that MIF mRNA and
protein expression was increased in the lung tissues from hypoxic
pulmonary hypertensive rats. Intensive immunoreactivity for MIF
was observed in smooth muscle cells of large pulmonary arteries
(PAs), endothelial cells of small PAs, and inflammatory cells of
hypoxic lungs. MIF participated in the hypoxia-induced PASMCs
proliferation, and it could directly stimulate proliferation of
these cells. MIF-induced enhanced growth of PASMCs was attenuated
by MEK and JNK inhibitor. Besides, MIF antagonist ISO-1 suppressed
the ERK1/2 and JNK phosphorylation induced by MIF. In conclusion,
the current finding suggested that MIF may act on the
proliferation of PASMCs through the activation of the ERK1/2 and
JNK pathways, which contributes to hypoxic pulmonary hypertension
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