The chalcogenide complexes Zr(η
5-(C
5Me
5)
2(E)) (E=S, Se), (generated in situ from the corresponding pyridine adducts), undergo 2+2 cyclo-addition reactions with the phospha-alkyne
t
BuCP to ...afford the structurally characterised complexes Zr(η
5-(C
5Me
5)
2(SC(
t
Bu)P)) and Zr(η
5-(C
5Me
5)
2(SeC(
t
Bu)P)). The former complex undergoes ring expansion reactions with either selenium to afford Zr(η
5-(C
5Me
5)
2(SC(
t
Bu)PSe)) or with PhCN to give Zr(η
5(C
5Me
5)
2(SC(
t
Bu)PC(Ph)N)) which have also been characterised structurally.
2+2 Cyclo-addition reactions of chalcogenide (S, Se and Te) complexes of zirconium with the phospha-alkyne
t
BuCP are reported and further ring expansions with chalcogens and PhCN are described. NMR and single crystal data of the products are presented.
We describe the synthesis and characterization of a family of materials, Zr1–x Sn x Mo2O8 (0 < x < 1), whose isotropic thermal expansion coefficient can be systematically varied from negative to zero ...to positive values. These materials allow tunable expansion in a single phase as opposed to using a composite system. Linear thermal expansion coefficients, αl, ranging from −7.9(2) × 10–6 to +5.9(2) × 10–6 K–1 (12–500 K) can be achieved across the series; contraction and expansion limits are of the same order of magnitude as the expansion of typical ceramics. We also report the various structures and thermal expansion of “cubic” SnMo2O8, and we use time- and temperature-dependent diffraction studies to describe a series of phase transitions between different ordered and disordered states of this material.
The atmospheres of late M stars represent a significant challenge in the characterization of any transiting exoplanets due to the presence of strong molecular features in the stellar atmosphere. ...TRAPPIST-1 is an ultra-cool dwarf, host to seven transiting planets, and contains its own molecular signatures which can potentially be imprinted on planetary transit lightcurves due to inhomogeneities in the occulted stellar photosphere. We present a case study on TRAPPIST-1g, the largest planet in the system, using a new observation together with previous data, to disentangle the atmospheric transmission of the planet from that of the star. We use the out-of-transit stellar spectra to reconstruct the stellar flux based on one-, two-, and three-temperature components. We find that TRAPPIST-1 is a 0.08 M\(_*\), 0.117 R\(_*\), M8V star with a photospheric effective temperature of 2400 K, with ~35% 3000 K spot coverage and a very small fraction, <3%, of ~5800 K hot spot. We calculate a planetary radius for TRAPPIST-1g to be Rp = 1.124 R\(_\oplus\) with a planetary density of \(\rho_p\) = 0.8214 \(\rho_\oplus\). Based on the stellar reconstruction there are eleven plausible scenarios for the combined stellar photosphere and planet transit geometry; in our analysis we are able to rule out 8 of the 11 scenarios. Using planetary models we evaluate the remaining scenarios with respect to the transmission spectrum of TRAPPIST-1g. We conclude that the planetary transmission spectrum is likely not contaminated by any stellar spectral features, and are able to rule out a clear solar H2/He-dominated atmosphere at greater than 3-sigma.
New synthetic routes to the 1,2,4- and 1,3,4-thiadiphospholes, P
2SC
2Bu
t
2, are presented. Both η
1-W(CO)
5 and η
5-M(CO)
3 complexes (M=Mo, W) of the 1,2,4-thiadiphosphole ring are described and ...the molecular structure of the former determined by a single crystal X-ray study is in good agreement with theoretical calculations. The thermal conversion of the η
1-M(CO)
5 complex to the η
5-M(CO)
3 complex is attributable to the entropy change in the reaction. A sequence of 4+2 and 2+2+2 cyclo-addition reactions of the 1,2,4-thiadiphosphole, P
2SC
2Bu
t
2, with the phosphaalkyne, PCBu
t
, affords the tetracyclic cage compound P
4SC
4Bu
t
4 which has also been structurally characterised.
New routes to the 1,2,4- and 1,3,4-thiadiphospholes, P
2SC
2Bu
t
2, are presented. η
1-W(CO)
5 and η
5-M(CO)
3 complexes (M=Mo, W) of the 1,2,4-thiadiphosphole ring are described and the molecular structure of the former is in good agreement with theoretical calculations. The η
1-M(CO)
5 complex readily converts to the η
5-M(CO)
3 complex in an entropy controlled reaction. Cyclo-addition reactions of the 1,2,4-thiadiphosphole, and PCBu
t
affords the P
4SC
4Bu
t
4 cage.
Atopic dermatitis (AD) is a chronic itch and inflammatory disorder of the skin that affects one in ten people. Patients suffering from severe AD eventually progress to develop asthma and allergic ...rhinitis, in a process known as the “atopic march.” Signaling between epithelial cells and innate immune cells via the cytokine thymic stromal lymphopoietin (TSLP) is thought to drive AD and the atopic march. Here, we report that epithelial cells directly communicate to cutaneous sensory neurons via TSLP to promote itch. We identify the ORAI1/NFAT calcium signaling pathway as an essential regulator of TSLP release from keratinocytes, the primary epithelial cells of the skin. TSLP then acts directly on a subset of TRPA1-positive sensory neurons to trigger robust itch behaviors. Our results support a model whereby calcium-dependent TSLP release by keratinocytes activates both primary afferent neurons and immune cells to promote inflammatory responses in the skin and airways.
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•Epithelial cells communicate to sensory neurons via TSLP to promote itch•ORAI1/NFAT calcium signaling regulates release of TSLP from keratinocytes•TSLP is a robust pruritogen that promotes itch-evoked scratching•TSLP-evoked itch behaviors require TRPA1 ion channels that promote inflammation
The proinflammatory cytokine TSLP is a potent driver of dermatitis and is primarily thought to act through modulation of immune cells. TSLP is now found to directly activate sensory neurons via signaling involving ORAI1 and TRPA1 channels to trigger itch behaviors.
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