Observation of forbidden phonons and dark excitons by resonance Raman scattering in few-layer WS2_2

The optical properties of the two-dimensional (2D) crystals are dominated by tightly bound electron-hole pairs (excitons) and lattice vibration modes (phonons). The exciton-phonon interaction is fundamentally important to understand the optical properties of 2D materials and thus help develop emerging 2D crystal based optoelectronic devices. Here, we presented the excitonic resonant Raman scattering (RRS) spectra of few-layer WS$_2$ excited by 11 lasers lines covered all of A, B and C exciton transition energies at different sample temperatures from 4 to 300 K. As a result, we are not only able to probe the forbidden phonon modes unobserved in ordinary Raman scattering, but also can determine the bright and dark state fine structures of 1s A exciton. In particular, we also observed the quantum interference between low-energy discrete phonon and exciton continuum under resonant excitation. Our works pave a way to understand the exciton-phonon coupling and many-body effects in 2D materials.Comment: 14 pages, 11 figure

Clematis chinensis Extract Protects against Diabetic Nephropathy in Rats

Purpose: To study the effect of Clematis chinensis extract (CCE) on diabetic nephropathy in rats.Methods: Eight-week old male Wistar rats were injected with streptozotocin to induce diabetes. The effects of CCE(250 or 500 mg/kg) on renal function index, fasting blood glucose (FBG), blood fat, oxidation index, and pathological kidney changes for 3 weeks were compared to those of the positive control drug, captopril.Results: At 12 weeks, CCE(500 mg/kg) treatment had significantly decreased serum blood urea nitrogen (BUN, 12.61 ± 1.42 mmol/L), serum creatinine (SCr, 84.64 ± 6.37 μmol/L), creatinine clearance (CCr, 0.88 ± 0.10 mmol/L), interleukin-6 (IL-6, 297.56 ± 19.62 pg/mL), urinary albumin, urinary albumin excretion rate (UAER, 11.68 ± 0.97 μg/min), kidney hypertrophy index (kidney weight/body weight, 0.58 ± 0.03%) and FBG (11.51 ± 0.96 mmol·L-1). It significantly decreased triglyceride (TG, 0.26 ± 0.05 mmol/L), total cholesterol (TC, 1.52 ± 0.06 mmol/L) and low-density lipoprotein cholesterol (LDL-c, 0.71 ± 0.06 mmol/L) levels and increased high density lipoprotein-cholesterol (HDL-c, 0.65 ± 0.05 mmol/L). CCE treatment also significantly decreased malondialdehyde (MDA, 16.14 ± 1.24 nmol/mgprot) levels and increased superoxide dismutase (SOD, 95.17 ± 4.06 U/mgprot) and glutathione peroxidase (GSHPx, 154.33 ± 11.76 mmol/L) (both p < 0.05). Finally, CCE reduced the degree of glomerular basement membrane and renal tubular thickening and swelling in diabetic rats.Conclusion: CCE has a significant inhibitory effect on diabetic nephropathy-induced renal injury in rats.Keywords: Clematis chinensis, Diabetic nephropathy, Renal function, Pathological morpholog

Up-regulation of fas reverses cisplatin resistance of human small cell lung cancer cells

<p>Abstract</p> <p>Background/Aim</p> <p>Fas/FasL system is a major regulator of apoptosis. The mechanisms by which Fas mediates cisplatin resistance remain unclear. The aim of this study is to explore the effect of Fas over-expression on cisplatin resistance of small cell lung cancer cells and its possible mechanisms.</p> <p>Materials and methods</p> <p>Fas was over-expressed in H446/CDDP cells by infection with the adenoviruses containing Fas. Sensitivity of Fas-overexpressed H446/CDDP cells to cisplatin was evaluated using MTT assay. Expressions of Fas, GST-π and ERCC1 were detected by RT-PCR and Western blot analysis. Apoptosis rate was examined by FACS.</p> <p>Results</p> <p>Over-expression of Fas in H446/CDDP cells significantly decreased the expressions of GST-π and ERCC1 at mRNA and protein levels, and increased the cell apoptosis. Furthermore, up-regulation of Fas significantly decreased the tolerance of H446/CDDP cells to cisplatin.</p> <p>Conclusion</p> <p>Over-expression of Fas reverses drug resistance of H446/CDDP cells, possibly due to the increased cell sensitivity to apoptosis and the decreased expressions of GST-π and ERCC1.</p

Artificial intelligence enhances the performance of chaotic baseband wireless communication

Funding Information: This work was supported in part by Shaanxi Provincial Special Support Program for Science and Technology Innovation Leader. Dr Bai was supported in part by China Postdoctoral Science Foundation Funded Project (2020M673349), and Open Research Fund from Shaanxi Key Laboratory of Complex System Control and Intelligent Information Processing (2020CP02).Peer reviewedPublisher PD

6-Benzyl-3-[(6-chloro­pyridin-3-yl)meth­yl]-6,7-dihydro-3H-1,2,3-triazolo[4,5-d]pyrimidin-7-imine

The title compound, C17H14ClN7, crystallizes with two independent mol­ecules in the asymmetric unit. Inter­molecular N—H⋯N and C—H⋯N hydrogen bonds contribute to the stability of the crystal structure. In addition, weak C—H⋯π and π–π stacking [centroid–centroid distances of 3.699 (8) and 3.699 (6) Å] interactions are observed

Superelasticity of Carbon Nanocoils from Atomistic Quantum Simulations

A structural model of carbon nanocoils (CNCs) on the basis of carbon nanotubes (CNTs) was proposed. The Young’s moduli and spring constants of CNCs were computed and compared with those of CNTs. Upon elongation and compression, CNCs exhibit superelastic properties that are manifested by the nearly invariant average bond lengths and the large maximum elastic strain limit. Analysis of bond angle distributions shows that the three-dimensional spiral structures of CNCs mainly account for their unique superelasticity

Is Floppy Eyelid Syndrome More Prevalent in Obstructive Sleep Apnea Syndrome Patients?

Controversial findings are reported about the relationship between floppy eyelid syndrome (FES) and obstructive sleep apnea syndrome (OSAS). The main goal of this study was to evaluate whether FES is more prevalent in OSAS patients by performing a meta-analysis. A comprehensive literature search of Pubmed, Embase, and Cochrane databases was performed. Only studies related to the prevalence of FES in OSAS were included in the meta-analysis. We estimated a pooled odds ratio (OR) for the prevalence of FES in OSAS. In total, 6 studies with 767 participants met the inclusion criteria. Using a fixed-effects model, the pooled OR was 4.12. The test for the overall effect revealed that FES was statistically prevalent in OSAS patients when compared with that in non-OSAS subjects (Z=4.98, p<0.00001). In the subgroup analysis by OSAS severity, the incidence of FES in OSAS increased with severity of OSAS as indicated with increased OR values (OR = 2.56, 4.62, and 7.64 for mild, moderate, and severe OSAS). In conclusion, the results indicate that FES is more prevalent in OSAS patients. However, this result was based only on unadjusted estimates. Prospective cohort studies are needed to determine whether OSAS is an independent risk factor for FES

Quantum blockade and loop current induced by a single lattice defect in graphene nanoribbons

We investigate theoretically the electronic transport properties in narrow graphene ribbons with an adatom-induced defect. It is found that the lowest conductance step of a metallic graphene nanoribbon may develop a dip even down to zero at certain values of the Fermi energy due to the defect. Accompanying the occurrence of the conductance dip, a loop current develops around the defect. We show how the properties of the conductance dip depend on the parameters of the defect, such as the relative position and severity of the defect as well as the width and edges of the graphene ribbons. In particular, for metallic armchair-edges graphene nanoribbons, whether the conductance dip appears or not, they can be controlled by choosing the position of the single defect.Comment: 6 pages, 6 figure