Gate controlled valley polarizer in bilayer graphene

Sign reversal of Berry curvature across two oppositely gated regions in bilayer graphene can give rise to counter-propagating 1D channels with opposite valley indices. Considering spin and sub-lattice degeneracy, there are four quantized conduction channels in each direction. Previous experimental work on gate-controlled valley polarizer achieved good contrast only in the presence of an external magnetic field. Yet, with increasing magnetic field the ungated regions of bilayer graphene will transit into the quantum Hall regime, limiting the applications of valley-polarized electrons. Here we present improved performance of a gate-controlled valley polarizer through optimized device geometry and stacking method. Electrical measurements show up to two orders of magnitude difference in conductance between the valley-polarized state and gapped states. The valley-polarized state displays conductance of nearly 4e2/h and produces contrast in a subsequent valley analyzer configuration. These results pave the way to further experiments on valley-polarized electrons in zero magnetic field

Nonhomogeneous fractional p-Kirchhoff problems involving a critical nonlinearity

This paper is concerned with the existence of solutions for a kind of nonhomogeneous critical $p$-Kirchhoff type problem driven by an integro-differential operator $\mathcal{L}^{p}_{K}$. In particular, we investigate the equation: \begin{align*} \mathcal{M}\left(\iint_{\mathbb{R}^{2n}}\frac{|v(x)-v(y)|^{p}}{|x-y|^{n+ps}}dxdy\right) \mathcal{L}^{p}_{K}v(x)=\mu g(x)|v|^{q-2}v+|v|^{p_{s}^{*}-2}v+\mu f(x) \quad\mbox{in}~\mathbb{R}^{n}, \end{align*} where $g(x)>0$, and $f(x)$ may change sign, $\mu>0$ is a real parameter, $0ps$, $1<q<p<p_{s}^{*}$, $p_{s}^{*}=\frac{np}{n-ps}$ is the critical exponent of the fractional Sobolev space $W^{s,p}_{K}(\mathbb{R}^{n}).$ By exploiting Ekeland's variational principle, we show the existence of non-trivial solutions. The main feature and difficulty of this paper is the fact that $\mathcal{M}$ may be zero and lack of compactness at critical level $L^{p_{s}^{*}}(\mathbb{R}^{n})$. Our conclusions improve the related results on this topic

Nonhomogeneous fractional p-Kirchhoff problems involving a critical nonlinearity

This paper is concerned with the existence of solutions for a kind of nonhomogeneous critical p-Kirchhoff type problem driven by an integro-differential operator L p K . In particular, we investigate the equation: M �ZZ R2n |v(x) − v(y)| p |x − y| n+ps dxdy� L p K v(x) = µg(x)|v| q−2 v + |v| p s −2 v + µ f(x) in R n where g(x) > 0, and f(x) may change sign, µ > 0 is a real parameter, 0 ps, 1 < q < p < p s , p s = np n−ps is the critical exponent of the fractional Sobolev space W s,p K (Rn ). By exploiting Ekeland’s variational principle, we show the existence of non-trivial solutions. The main feature and difficulty of this paper is the fact that M may be zero and lack of compactness at critical level L p s (Rn Our conclusions improve the related results on this topic

(2,4-Difluoro­phen­yl)[1-(1H-1,2,4-triazol-1-yl)cyclo­prop­yl]methanone

The asymmetric unit of the title compound, C12H9F2N3O, contains two independent mol­ecules (A and B) in which the benzene and cyclo­propane rings form dihedral angles of 33.0 (1) and 29.7 (1)°, respectively. In the crystal, weak inter­molecular C—H⋯O hydrogen bonds link alternating A and B mol­ecules into chains along [010]

Nonhomogeneous fractional pp-Kirchhoff problems involving a critical nonlinearity

This paper is concerned with the existence of solutions for a kind of nonhomogeneous critical $p$-Kirchhoff type problem driven by an integro-differential operator $\mathcal{L}^{p}_{K}$. In particular, we investigate the equation: \begin{align*} \mathcal{M}\left(\iint_{\mathbb{R}^{2n}}\frac{|v(x)-v(y)|^{p}}{|x-y|^{n+ps}}dxdy\right) \mathcal{L}^{p}_{K}v(x)=\mu g(x)|v|^{q-2}v+|v|^{p_{s}^{*}-2}v+\mu f(x) \quad\mbox{in}~\mathbb{R}^{n}, \end{align*} where $g(x)>0$, and $f(x)$ may change sign, $\mu>0$ is a real parameter, $0ps$, $1<q<p<p_{s}^{*}$, $p_{s}^{*}=\frac{np}{n-ps}$ is the critical exponent of the fractional Sobolev space $W^{s,p}_{K}(\mathbb{R}^{n}).$ By exploiting Ekeland's variational principle, we show the existence of non-trivial solutions. The main feature and difficulty of this paper is the fact that $\mathcal{M}$ may be zero and lack of compactness at critical level $L^{p_{s}^{*}}(\mathbb{R}^{n})$. Our conclusions improve the related results on this topic

Infinitely Many Solutions for a Superlinear Fractional p-Kirchhoff-Type Problem without the (AR) Condition

In this paper, we investigate the existence of infinitely many solutions to a fractional p-Kirchhoff-type problem satisfying superlinearity with homogeneous Dirichlet boundary conditions as follows: [a+b(∫R2Nux-uypKx-ydxdy)]Lpsu-λ|u|p-2u=gx,u, in  Ω, u=0, in  RN∖Ω, where Lps is a nonlocal integrodifferential operator with a singular kernel K. We only consider the non-Ambrosetti-Rabinowitz condition to prove our results by using the symmetric mountain pass theorem

Introducing catalyst in alkaline membrane for improved performance direct borohydride fuel cells

A catalytic material is introduced into the polymer matrix to prepare a novel polymeric alkaline electrolyte membrane (AEM) which simultaneously increases ionic conductivity, reduces the fuel cross-over. In this work, the hydroxide anion exchange membrane is mainly composed of poly(vinylalcohol) and alkaline exchange resin. CoCl2 is added into the poly(vinylalcohol) and alkaline exchange resin gel before casting the membrane to introduce catalytic materials. CoCl2 is converted into CoOOH after the reaction with KOH solution. The crystallinity of the polymer matrix decreases and the ionic conductivity of the composite membrane is notably improved by the introduction of Co-species. A direct borohydride fuel cell using the composite membrane exhibits an open circuit voltage of 1.11 V at 30 °C, which is notably higher than that of cells using other AEMs. The cell using the composite membrane achieves a maximum power density of 283 mW cm−2 at 60 °C while the cell using the membrane without Co-species only reaches 117 mW cm−2 at the same conditions. The outstanding performance of the cell using the composite membrane benefits from impregnation of the catalytic Co-species in the membrane, which not only increases the ionic conductivity but also reduces electrode polarization thus improves the fuel cell performance. This work provides a new approach to develop high-performance fuel cells through adding catalysts in the electrolyte membrane

Traditional Chinese Medicine Shi-Bi-Man regulates lactic acid metabolism and drives hair follicle stem cell activation to promote hair regeneration

Abstract Background As a supplement for promoting hair health, Shi-Bi-Man (SBM) is a prescription comprising various traditional Chinese medicines. Though SBM has been reported to promote hair regeneration, its molecular mechanism remains unclear. Cynomolgus monkeys (Macaca fascicularis) are non-human primates with a gene expression profile similar to that of humans. The purpose of this research is to evaluate the effect of SBM on promoting hair regeneration in cynomolgus monkeys and to reveal the underlying mechanism. Methods The effect of SBM on hair regeneration was observed by skin administration on 6 cynomolgus monkeys with artificial back shaving. The molecular mechanism of SBM was studied using single-cell RNA sequencing (scRNA-seq) in combination with quantitative polymerase chain reaction (qPCR) detection for gene transcription level, and immunofluorescence staining verification for protein level. Results SBM significantly induced hair regeneration in cynomolgus monkeys, increased hair follicle number and facilitated hair follicle development. ScRNA-seq revealed an increase in the number of hair follicle stem cells (HFSCs) with a higher activation state, as evidenced by the higher expression of activation marker LDHA related to metabolism and the proliferation marker MKI67. Immunofluorescence analysis at the protein level and qPCR at the mRNA level confirmed the sequencing data. Cellchat analysis revealed an enrichment of ligand-receptor pairs involved in intercellular communication in Laminin-related pathways. Conclusion SBM significantly promotes hair regeneration in cynomolgus monkeys. Mechanically, SBM can up-regulate LDHA-mediated lactic acid metabolism and drive HFSC activation, which in turn promotes the proliferation and differentiation of HFSCs

Identification of a novel glycolysis-related prognosis risk signature in triple-negative breast cancer

IntroductionTriple-negative breast cancer (TNBC) is a particularly aggressive cluster of breast cancer characterized by significant molecular heterogeneity. Glycolysis is a metabolic pathway that is significantly associated with cancer progression, metastasis, recurrence and chemoresistance. However, the potential roles of glycolysis-related genes in TNBC remain unclear.MethodsIn the present study, we identified 108 glycolysis-related differentially expressed genes (DEGs) between breast cancer (BRCA) tumor tissues and normal tissues, and we divided patients into two different clusters with significantly distinct molecular characteristics, clinicopathological features, prognosis, immune cell infiltration and mutation burden. We then constructed a 10-gene signature that classified all TNBCs into low- and high-risk groups.ResultsThe high-risk group had significantly lower survival than the low-risk group, which implied that the risk score was an independent prognostic indicator for TNBC patients. Consequently, we constructed and validated a prognostic nomogram, which accurately predicted individual overall survival (OS) of TNBC. Moreover, the risk score predicted the drug sensitivity of chemotherapeutic agents and immunotherapy for TNBC patients.DiscussionThe present comprehensive analysis of glycolysis-related DEGs in TNBC provides new methods for prognosis prediction and more effective treatment strategies