Observation of topological flat bands in the kagome semiconductor Nb3_3Cl8_8

The destructive interference of wavefunctions in a kagome lattice can give rise to topological flat bands (TFBs) with a highly degenerate state of electrons. Recently, TFBs have been observed in several kagome metals, including Fe$_3$Sn$_2$, FeSn, CoSn, and YMn$_6$Sn$_6$. Nonetheless, kagome materials that are both exfoliable and semiconducting are lacking, which seriously hinders their device applications. Herein, we show that Nb$_3$Cl$_8$, which hosts a breathing kagome lattice, is gapped out because of the absence of inversion symmetry, while the TFBs survive because of the protection of the mirror reflection symmetry. By angle-resolved photoemission spectroscopy measurements and first-principles calculations, we directly observe the TFB and a moderate band gap in Nb$_3$Cl$_8$. By mechanical exfoliation, we successfully obtain monolayers of Nb$_3$Cl$_8$ and confirm that they are stable under ambient conditions. In addition, our calculations show that monolayers of Nb$_3$Cl$_8$ have a magnetic ground state, thus providing opportunities to study the interplay between geometry, topology, and magnetism.Comment: 6 pages, 4 figure

Construction of β-Haloenamides via Direct Copper-Promoted Coupling of Lactams with 2-Chloro and 2-Bromo Vinyliodides.

Cu(I)-catalyzed coupling of lactams with (E)-2-chlorovinyl iodides or (E)-2-bromovinyl iodides produces the corresponding β-halo enamides in moderate to excellent yields. E.g., in the presence of CuI and MeNHCH2CH2NHMe, coupling of (E)-2-chlorovinyl iodide I with lactam II gave 43% β-halo enamide III. [on SciFinder(R)

Europe : France : Rhône-Alpes : Haute-Savoie : Glacier des Bossons et moraine frontale

Commentaire de l'auteur en 2016: ---- Contexte ---- Voyage personnel, alpinisme.Légende manuscrite sur le document original : "Glacier des Bossons et moraine frontale du "petit âge glaciaire" [Indiqués sur la diapo de g à dr: Mt Blanc du Tacul, Mt Maudit, Mt Blanc, Glacier Taconnez]" Géolocalisation : Hypothèse de géolocalisation exacte

Candida albicans Heat Shock Proteins and Hsps-Associated Signaling Pathways as Potential Antifungal Targets

In recent decades, the incidence of invasive fungal infections has increased notably. Candida albicans (C. albicans), a common opportunistic fungal pathogen that dwells on human mucosal surfaces, can cause fungal infections, especially in immunocompromised and high-risk surgical patients. In addition, the wide use of antifungal agents has likely contributed to resistance of C. albicans to traditional antifungal drugs, increasing the difficulty of treatment. Thus, it is urgent to identify novel antifungal drugs to cope with C. albicans infections. Heat shock proteins (Hsps) exist in most organisms and are expressed in response to thermal stress. In C. albicans, Hsps control basic physiological activities or virulence via interaction with a variety of diverse regulators of cellular signaling pathways. Moreover, it has been demonstrated that Hsps confer drug resistance to C. albicans. Many studies have shown that disrupting the normal functions of C. albicans Hsps inhibits fungal growth or reverses the tolerance of C. albicans to traditional antifungal drugs. Here, we review known functions of the diverse Hsp family, Hsp-associated intracellular signaling pathways and potential antifungal targets based on these pathways in C. albicans. We hope this review will aid in revealing potential new roles of C. albicans Hsps in addition to canonical heat stress adaptions and provide more insight into identifying potential novel antifungal targets

A pointwise approximation theorem for linear combinations of Bernstein polynomials

Recently, Z. Ditzian gave an interesting direct estimate for Bernstein polynomials. In this paper we give direct and inverse results of this type for linear combinations of Bernstein polynomials

Potential antifungal targets against a Candida biofilm based on an enzyme in the arachidonic acid cascade - a review

Candida is an important opportunistic fungal pathogen, especially in biofilm associated infections. The formation of a Candida biofilm can decrease Candida sensitivity to antifungal drugs and cause drug resistance. Although many effective antifungal drugs are available, their applications are limited due to their high toxicity and cost. Seeking new antifungal agents that are effective against biofilm-associated infection is an urgent need. Many research efforts are underway, and some progress has been made in this field. It has been shown that the arachidonic acid cascade plays an important role in fungal morphogenesis and pathogenicity. Notably, prostaglandin E2 (PGE2) can promote the formation of a Candida biofilm. Recently, the inhibition of PGE2 has received much attention. Studies have shown that cyclooxygenase (COX) inhibitors, such as aspirin, ibuprofen and indomethacin, combined with fluconazole can significantly reduce Candida adhesion and biofilm development and increase fluconazole susceptibility; the MIC of fluconazole can be decrease from 64 to 2 μg/ml when used in combination with ibuprofen. In addition, in vivo studies have also confirmed the antifungal activities of these inhibitors. In this article, we mainly review the relationship between PGE2 and Candida biofilm, summarize the antifungal activities of COX inhibitors and analyze the possible antifungal activity of microsomal prostaglandin E synthase-1 (MPGES-1) inhibitors; additionally, other factors that influence PGE2 production are also discussed. Hopefully this review can disclose potential antifungal targets based on the arachidonic acid cascade and provide a prevailing strategy to alleviate C. albicans biofilm formation

Relative expressions of <i>CDR1</i>, <i>CDR2</i>, <i>MDR1</i> and <i>FLU1</i> in resistant <i>C</i>. <i>albicans</i>.

<p>CA10 cells were treated with t no agent, 1μg/mL FLC, 128μg/mL BUD, and a combination of FLC and BUD at the same concentration. Error bars indicated standard errors of the means. Statistical significances were determined by Student’s t-test. *<i>P</i> < 0.05 when compared with the respective controls.</p

Synergic effects of FLC alone and in combination with BUD against biofilms of resistant <i>C</i>. <i>albicans</i>.

<p>Synergic effects of FLC alone and in combination with BUD against biofilms of resistant <i>C</i>. <i>albicans</i>.</p

Fungal burden in infected <i>G</i>. <i>mellonella</i> over 4 days.

<p>The concentration of yeast cells was 5 × 10⁶ CFU/larva. Treatments consisted of PBS, FLC (160μg/mL) alone, BUD (160μg/mL) alone, or a combination of FLC (160μg/mL) with BUD (160μg/mL). Data came from the means of three independent experiments. For clarity, data for treatment with BUD are not shown because the data obtained closely followed those shown for the control group.</p