1,842 research outputs found
Observation of Ultrahigh Mobility Surface States in a Topological Crystalline Insulator by Infrared Spectroscopy
Topological crystalline insulators (TCIs) possess metallic surface states
protected by crystalline symmetry, which are a versatile platform for exploring
topological phenomena and potential applications. However, progress in this
field has been hindered by the challenge to probe optical and transport
properties of the surface states owing to the presence of bulk carriers. Here
we report infrared (IR) reflectance measurements of a TCI, (001) oriented
in zero and high magnetic fields. We demonstrate that the
far-IR conductivity is unexpectedly dominated by the surface states as a result
of their unique band structure and the consequent small IR penetration depth.
Moreover, our experiments yield a surface mobility of 40000 ,
which is one of the highest reported values in topological materials,
suggesting the viability of surface-dominated conduction in thin TCI crystals.
These findings pave the way for exploring many exotic transport and optical
phenomena and applications predicted for TCIs
Heat Shock Protein 70 Protects the Heart from Ischemia/Reperfusion Injury through Inhibition of p38 MAPK Signaling.
BackgroundHeat shock protein 70 (Hsp70) has been shown to exert cardioprotection. Intracellular calcium ([Ca2+]i) overload induced by p38 mitogen-activated protein kinase (p38 MAPK) activation contributes to cardiac ischemia/reperfusion (I/R) injury. However, whether Hsp70 interacts with p38 MAPK signaling is unclear. Therefore, this study investigated the regulation of p38 MAPK by Hsp70 in I/R-induced cardiac injury.MethodsNeonatal rat cardiomyocytes were subjected to oxygen-glucose deprivation for 6 h followed by 2 h reoxygenation (OGD/R), and rats underwent left anterior artery ligation for 30 min followed by 30 min of reperfusion. The p38 MAPK inhibitor (SB203580), Hsp70 inhibitor (Quercetin), and Hsp70 short hairpin RNA (shRNA) were used prior to OGD/R or I/R. Cell viability, lactate dehydrogenase (LDH) release, serum cardiac troponin I (cTnI), [Ca2+]i levels, cell apoptosis, myocardial infarct size, mRNA level of IL-1β and IL-6, and protein expression of Hsp70, phosphorylated p38 MAPK (p-p38 MAPK), sarcoplasmic/endoplasmic reticulum Ca2+-ATPase2 (SERCA2), phosphorylated signal transducer and activator of transcription3 (p-STAT3), and cleaved caspase3 were assessed.ResultsPretreatment with a p38 MAPK inhibitor, SB203580, significantly attenuated OGD/R-induced cell injury or I/R-induced myocardial injury, as evidenced by improved cell viability and lower LDH release, resulted in lower serum cTnI and myocardial infarct size, alleviation of [Ca2+]i overload and cell apoptosis, inhibition of IL-1β and IL-6, and modulation of protein expressions of p-p38 MAPK, SERCA2, p-STAT3, and cleaved-caspase3. Knockdown of Hsp70 by shRNA exacerbated OGD/R-induced cell injury, which was effectively abolished by SB203580. Moreover, inhibition of Hsp70 by quercetin enhanced I/R-induced myocardial injury, while SB203580 pretreatment reversed the harmful effects caused by quercetin.ConclusionsInhibition of Hsp70 aggravates [Ca2+]i overload, inflammation, and apoptosis through regulating p38 MAPK signaling during cardiac I/R injury, which may help provide novel insight into cardioprotective strategies
Revisiting Galaxy Evolution in Morphology in the COSMOS field (COSMOS-ReGEM):I. Merging Galaxies
We revisit the evolution of galaxy morphology in the COSMOS field over the
redshift range , using a large and complete sample of 33,605
galaxies with a stellar mass of log(/M with
significantly improved redshifts and comprehensive non-parametric morphological
parameters. Our sample has 13,881 () galaxies with reliable
spectroscopic redshifts and has more accurate photometric redshifts with a
. This paper is the first in a series that
investigates merging galaxies and their properties. We identify 3,594 major
merging galaxies through visual inspection and find 1,737 massive galaxy pairs
with log(/M). Among the family of non-parametric
morphological parameters including , , , , , , and , we find that the outer asymmetry parameter
and the second-order momentum parameter are the best tracers of
merging features than other combinations. Hence, we propose a criterion for
selecting candidates of violently star-forming mergers: at at .
Furthermore, we show that both the visual merger sample and the pair sample
exhibit a similar evolution in the merger rate at , with for the visual merger sample and for the pair sample. The visual merger sample has a
specific star formation rate that is about 0.16\,dex higher than that of
non-merger galaxies, whereas no significant star formation excess is observed
in the pair sample. This suggests that the effects of mergers on star formation
differ at different merger stages.Comment: 21 pages, 12 figures; accepted for publication in Ap
糖尿病培训手册在培养糖尿病护士的应用
Objective: To explore the nursing service mode for specialized nurses in diabetes and its application effect. Methods:In view of the actual situation of our hospital, a special training manual named with Diabetes training manual was prior composed. 40 specialized nurses in diabetes were trained with the special training manual. Training lasted for 3 months. After the training, the specialized nurses were assessed with the specialty knowledge of Diabetes Mellitus, the skill of clinical procedures, and the knowledge about patients' health education. Results: The skill of the trained nurses was improved. The satisfaction of patients was enhanced.Conclusion: Diabetes training manual can be used for specialized nurses in diabetes.目的 探讨糖尿病护士培训方式。方法 对2013年1—10月本院内分泌科的40名糖尿病护士培训,根据以往医院的培训,结合本院实际,应用自编的糖尿病培训手册,最后考核糖尿病专科理论、操作及宣教能力考核,培训时间为3个月。结果 培训前与培训后比较差别有统计学意义(P<0.05),理论、操作及健康宣教能力较培训前提高;提高了患者及新护士的满意度。结论 糖尿病培训手册可以用于培养糖尿病新护士
ent-Kaurane diterpenoids from the plant Wedelia trilobata
Four new ent-kaurane diterpenoids, namely, 3α-tigloyloxypterokaurene L(3) (1), ent-17-hydroxy-kaura-9(11),15-dien-19-oic acid (2), and wedelobatins A (3) and B (4), together with 11 known ent-kaurane diterpenoids (5-15), were isolated from the ethanol extract of Wedelia trilobata. All the structures of 1–15 were elucidated on the basis of spectroscopic studies. [Image: see text] ELECTRONIC SUPPLEMENTARY MATERIAL: Supplementary material is available for this article at 10.1007/s13659-013-0029-4 and is accessible for authorized users
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