Spectroscopic Visualization of Flat Bands in Magic-Angle Twisted Monolayer-Bilayer Graphene: Coexistence of Localization and Delocalization.

Recent transport studies have demonstrated the great potential of twisted monolayer-bilayer graphene (TMBG) as a new platform to host moiré flat bands with a higher tunability than twisted bilayer graphene (TBG). However, a direct visualization of the flat bands in TMBG and its comparison with the ones in TBG remain unexplored. Here, via fabricating on a single sample with exactly the same twist angle of ∼1.13°, we present a direct comparative study between TMBG and TBG using scanning tunneling microscopy and spectroscopy. We observe a sharp density of states peak near the Fermi energy in tunneling spectroscopy, confirming unambiguously the existence of flat electronic bands in TMBG. The bandwidth of this flat-band peak is found to be slightly narrower than that of the TBG, validating previous theoretical predictions. Remarkably, by measuring spatially resolved spectroscopy, combined with continuum model calculation, we show that the flat-band states in TMBG exhibit a unique layer-resolved localization-delocalization coexisting feature, which offers an unprecedented possibility to utilize their cooperation on exploring novel correlation phenomena. Our work provides important microscopic insight of flat-band states for better understanding the emergent physics in graphene moiré systems.

Xpert MTB/RIF Improves the Prognosis of Multidrug-Resistant Tuberculosis Patients Through Faster Diagnosis and Earlier Targeted Treatment: A Prospective Cohort Study.

Objective: To evaluate the effectiveness of Xpert MTB/RIF in patients with multidrug-resistant tuberculosis (MDR-TB). Methods: Seventy-five patients with MDR-TB were enrolled in this prospective cohort study and were divided into two groups. The observation group were given standardized anti-MDR-TB treatment regimen (6ZAmLfxPtoCs/18ZLfxPtoCs) immediately when they had two positive sputum Xpert MTB/RIF results of RIF resistance. The control group were not given standardized anti-MDR-TB regimen until culture-based drug-susceptibility testing suggested MDR-TB. Treatment effect index, foci absorption, conversion of sputum, treatment outcomes, and adverse reactions were observed. Fisher's exact test and chi-square test were used to compare the differences between groups. Results: Treatment effect index of the observation group significantly out-performed the control group (24/34, 70.6% vs. 17/38, 44.7%, p = 0.027). At the 6th month of treatment course, observation group achieved significantly higher conversion (28/34, 82.3% vs. 23/38, 60.5%, p = 0.042). The foci absorption, cavity change, conversion at the 24th month of course, or treatment outcome between two groups were not statistically different. Conclusion: Xpert MTB/RIF helps MDR-TB patients to start rational treatment regimen earlier and reach earlier sputum conversion.

Increased levels of lactate dehydrogenase and hypertension are associated with severe illness of COVID-19.

BACKGROUND: Coronavirus disease 2019 (COVID-19) is amid an ongoing pandemic. It has been shown that patients with cardiovascular comorbidities are at higher risk of severe illness of COVID-19. AIM: To find out the relationship between cardiovascular comorbidities and severe illness of COVID-19. METHODS: The clinical data of 140 COVID-19 patients treated from January 22, 2020 to March 3, 2020 at our hospital were retrospectively collected. The clinical characteristics were compared between patients with mild illness and those with severe illness. RESULTS: There were 75 male patients and 65 female patients (53.6% vs 46.4%). The mean age was 45.4 ± 14.6 years (range, 2-85 years). Most of the patients had mild illness (n = 114, 81.4%) and 26 patients had severe illness (18.6%). The most common symptom was fever (n = 110, 78.6%), followed by cough (n = 82, 58.6%) and expectoration (n = 51, 36.4%). Eight patients were asymptomatic but were positive for severe acute respiratory syndrome coronavirus 2 RNA. Patients with severe illness were significantly more likely to be hypertensive than those with mild illness [(10/26, 38.4%) vs (22/114, 19.3%), P = 0.036]. The levels of lactate dehydrogenase were significantly higher in the severe illness group than in the mild illness group (299.35 ± 68.82 vs 202.94 ± 63.87, P < 0.001). No patient died in either the severe illness or the mild illness group. CONCLUSION: Hypertension and elevated levels of lactate dehydrogenase may be associated with severe illness of COVID-19.

[Effect of sandblasting combined with femtosecond laser-etching on surface physicochemical properties of pure titanium].

PURPOSE: The aim of this study was to generate periodic microstructures on pure titanium surface by femtosecond laser-etching after sandblasting, and to assess the physicochemical properties of its surface. METHODS: Twelve pure titanium discs with diameter of 10 mm and thickness of 4 mm were used and divided into 3 groups according to different surface treatment methods: group S (sandblasting surface), group SA (sandblasting surface with acid-etching), and group SL (sandblasting surface with femtosecond laser-etching). Scanning electron microscopy (SEM) was used to observe the surface morphology. X-ray energy spectrum(EDS) was used to observe the surface chemical compositions. Three dimensional surface topography and surface roughness were evaluated by laser scanning confocal microscope (CLSM). The static contact angle was detected by high temperature wetting angle measuring instrument. SPSS19.0 software package was used for statistical analysis. RESULTS: SEM and CLSM showed well-distributed periodic and cyclic microstructure which formed second-order roughness composite structure in group SL. EDS analysis showed that the Al element on SL surface decreased (group SL 4.37%group SA 0.32>group S 0). Surface roughness analysis showed that surface roughness significantly increased in group SL [group SL (7.33±0.38)µm>group SA (1.08±0.12)µm>group S (1.05±0.14)µm](P<0.001). Static contact angle analysis showed that the static contact angle of surface was significantly reduced in group SL [group SL (34.4±2.5)°

Taurine inhibits serum deprivation-induced osteoblast apoptosis via the taurine transporter/ERK signaling pathway

Taurine has positive effects on bone metabolism. However, the effects of taurine on osteoblast apoptosis in vitro have not been reported. The aim of this study was to investigate the activity of taurine on apoptosis of mouse osteoblastic MC3T3-E1 cells. The data showed that 1, 5, 10, or 20 mM taurine resulted in 16.7, 34.2, 66.9, or 63.75 percent reduction of MC3T3-E1 cell apoptosis induced by the serum deprivation (serum-free α-MEM), respectively. Taurine (1, 5, or 10 mM) also reduced cytochrome c release and inhibited activation of caspase-3 and -9, which were measured using fluorogenic substrates for caspase-3/caspase-9, in serum-deprived MC3T3-E1 cells. Furthermore, taurine (10 mM) induced extracellular signal-regulated kinase (ERK) phosphorylation in MC3T3-E1 cells. Knockdown of the taurine transporter (TAUT) or treatment with the ERK-specific inhibitor PD98059 (10 μM) blocked the activation of ERK induced by taurine (10 mM) and abolished the anti-apoptotic effect of taurine (10 mM) in MC3T3-E1 cells. The present results demonstrate for the first time that taurine inhibits serum deprivation-induced osteoblast apoptosis via the TAUT/ERK signaling pathway.

Taurine inhibits serum deprivation-induced osteoblast apoptosis via the taurine transporter/ERK signaling pathway.

Taurine has positive effects on bone metabolism. However, the effects of taurine on osteoblast apoptosis in vitro have not been reported. The aim of this study was to investigate the activity of taurine on apoptosis of mouse osteoblastic MC3T3-E1 cells. The data showed that 1, 5, 10, or 20 mM taurine resulted in 16.7, 34.2, 66.9, or 63.75% reduction of MC3T3-E1 cell apoptosis induced by the serum deprivation (serum-free α-MEM), respectively. Taurine (1, 5, or 10 mM) also reduced cytochrome c release and inhibited activation of caspase-3 and -9, which were measured using fluorogenic substrates for caspase-3/caspase-9, in serum-deprived MC3T3-E1 cells. Furthermore, taurine (10 mM) induced extracellular signal-regulated kinase (ERK) phosphorylation in MC3T3-E1 cells. Knockdown of the taurine transporter (TAUT) or treatment with the ERK-specific inhibitor PD98059 (10 µM) blocked the activation of ERK induced by taurine (10 mM) and abolished the anti-apoptotic effect of taurine (10 mM) in MC3T3-E1 cells. The present results demonstrate for the first time that taurine inhibits serum deprivation-induced osteoblast apoptosis via the TAUT/ERK signaling pathway.