Cell-fate mapping was used to identify cells that respond to the hedgehog (HH) signaling pathway and that are incorporated into the theca cell layer during ovarian follicle development. Expression of ...Gli1 is increased by HH signaling and can be used as a marker of cells responsive to HH in reporter mice. In transgenic Gli1ERcre/tdT mice, injection of tamoxifen (TAM) induces cre-mediated recombination and expression of td tomato (tdT) which leads to permanent fluorescent marking of cells expressing Gli1 and their progeny. The identity of tdT-positive cells was determined by co-staining ovaries for endothelial cells (CD31), pericytes (CSPG4), vascular smooth muscle cells (VSMC; smooth muscle actin) and steroidogenic cells (cytochrome P450 17A1). Gli1ERcre/tdT mice were injected with TAM on the day of birth. Cells positive for tdT in 2-day-old mice were identified as pericytes, located primarily in the medulla of the ovary in close proximity to endothelial cells. In both prepubertal mice and adult mice treated with equine chorionic gonadotropin to induce the formation of preovulatory follicles, tdT-positive cells were located within the theca cell layer and were identified as pericytes, VSMC and steroidogenic theca cells. Granulosa cells are known to express two HH ligands, Indian HH and desert HH (DHH). In DHHcre/tdT reporter mice, endothelial cells were marked as tdT-positive indicating that endothelial cells, in addition to granulosa cells, express Dhh in the ovary. These findings suggest that HH signaling may stimulate the development of the vasculature along with steroidogenic capacity of the theca layer during follicle development.
Triply switchable CoII(dpzca)2 shows an abrupt, reversible, and hysteretic spin crossover (T 1/2↓ = 168 K, T 1/2↑ = 179 K, and ΔT 1/2 = 11 K) between the high-spin (HS) and low-spin (LS) states of ...cobalt(II), both of which have been structurally characterized. The spin transition is also reversibly triggered by pressure changes. Moreover, in a third reversible switching mechanism for this complex, the magnetic properties can be switched between HS cobalt(II) and LS cobalt(III) by redox.
Phosphonium poly(ionic liquid)s (PILs) have been studied as alternatives to more common ammonium and imidazolium PILs for potential transport and separation applications. This work characterizes the ...CO2, H2, N2, O2, CH4, and C2H4 single-gas permeability, diffusivity, solubility, and selectivity of free-standing films of poly((tri-n-alkyl)vinylbenzylphosphoniumbis(trifluoromethylsulfonyl)imide) PILs (i.e., poly(PnnnVBTf2N) where n=4, 6, 8). The gas permeability was found to increase approximately linearly with increasing alkyl chain length on the phosphonium group. To our knowledge, the CO2 permeability of 186 barrers observed for poly(P888VBTf2N) is the highest reported for neat PIL materials. In contrast, gas selectivity was observed to decrease with an increase in phosphonium alkyl chain length from n=4 to n=6, then remain approximately constant between n=6 and n=8. Additionally, the ionic conductivity of these materials was observed to increase from ca. 10−8 to ca. 10−5Scm−1 as the measurement temperature was increased from 25 to 105°C. At 25°C, the PIL with the shortest cation alkyl chain (n=4) was observed to have the lowest ionic conductivity. However at ca. 90°C, the expected trend of increasing ionic conductivity in the order n=4>n=6>n=8 was observed.
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•Light gas transport properties of phosphonium poly(ionic liquid) membranes.•Relatively high gas permeability for neat poly(ionic liquids).•Inverse H2/CO2 and N2/CH4 selectivity.•Ionic conductivity between 25 and 105°C.
Zeolite particles, cross-linked poly(room-temperature ionic liquid)s (poly(RTIL)s), and room-temperature ionic liquids (RTILs) are combined to form mixed-matrix-membranes (MMMs) that exhibit a ...CO2/CH4 selectivity of 90±10 and a CO2 permeability of 260±20 barrers. This ideal (i.e., single-gas) separation performance is among the best reported in the literature, comparable to that of thermally rearranged polymers. The MMMs reported herein are physically robust and easily processed into membranes via conventional solvent-casting techniques. The elucidation and optimization of factors responsible for generating high-performance MMMs for CO2/CH4 separations were found to include: zeolite particle type, zeolite particle loading, poly(RTIL) structure, amount of cross-linking, and zeolite dispersion method in the RTIL. Optimization of these factors produced enhanced CO2/CH4 separation that significantly exceeds the 2008 Robeson upper bound, while the MMMs remain mechanically robust and easy to process.
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•New poly(RTIL)-RTIL-zeolite MMMs surpass the 2008 upper bound for CO2/CH4 separation.•Liquid RTIL homogeneously disperses zeolite particles and stabilizes their surfaces.•CO2/CH4 separation performance increased with zeolite loading and particle type.•Glassier poly(RTIL)-based MMMs outperformed more rubbery ones.•Lightly cross-linked SAPO-34 MMMs outperformed more cross-linked analogs.
This work investigates the implications of natural-gas composition on the combustion in a heavy-duty natural-gas engine and on the associated pollutant emissions. In this engine system, natural gas ...is injected into the combustion chamber shortly before the end of the compression stroke; a diesel pilot that precedes the natural-gas injection provides the ignition source. The effects of adding ethane, propane, hydrogen, and nitrogen to the fuel are reported here. The results indicate that these additives had no significant effect on the engine’s power or fuel consumption. Emissions of unburned fuel are reduced for all additives through either enhanced ignition or combustion processes. Black carbon particulate matter emissions are increased by ethane and propane, but are virtually eliminated by including nitrogen or hydrogen in the fuel.
We have developed and fabricated thin-film composite (TFC) membranes with an active layer consisting of a room-temperature ionic liquid/polymerized (room-temperature ionic liquid) i.e., ...(RTIL)/poly(RTIL) composite material. The resulting membrane has a CO2 permeance of 6100 ± 400 GPU (where 1 GPU = 10–6 cm3/(cm2 s cmHg)) and an ideal CO2/N2 selectivity of 22 ± 2. This represents a new membrane with state-of-the-art CO2 permeance and good CO2/N2 selectivity. To our knowledge, this is the first example of a TFC gas separation membrane composed of an RTIL-containing active layer.
A novel bis(epoxide)-functionalized ionic liquid (IL) monomer has been reacted with a commercially available amine monomer to produce cross-linked, epoxy-amine-based poly(ionic liquid) (PIL) resins ...and PIL/IL ion-gels via step-growth (S-G) polymerization. The degree of chemical functionality was controlled by manipulating the monomer stoichiometric ratios. The S-G PIL resins were investigated for CO2 sorption and have a relatively high equilibrium loading of 1.0 mmol CO2/(g resin). PIL/IL ion-gel membranes were subsequently prepared and tested for CO2/light gas permeation. These materials have CO2/N2 and CO2/CH4 permselectivity values near the Robeson upper bound. Analysis of their gas permeation data revealed that these materials exhibit a rare case of inverse CO2/CH4 diffusion selectivity (DCO2/DCH4<1). This phenomenon was attributed to the interaction of CO2 with residual and formed amine groups in the S-G PIL, resulting in a low CO2 diffusivity compared to that of non-interacting CH4.
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Successful human social interactions frequently rely on appropriate interpersonal empathy and eye contact. Here, we report a previously unseen relationship between trait empathy and eye-gaze patterns ...to affective facial features in video-based stimuli. Fifty-nine healthy adult participants had their eyes tracked while watching a three-minute long "sad" and "emotionally neutral" video. The video stimuli portrayed the head and shoulders of the same actor recounting a fictional personal event. Analyses revealed that the greater participants' trait emotional empathy, the more they fixated on the eye-region of the actor, regardless of the emotional valence of the video stimuli. Our findings provide the first empirical evidence of a relationship between empathic capacity and eye-gaze pattern to the most affective facial region (eyes).
This work reports on a promising strategy for the development of novel grafted ionic liquid membranes (GILMs) in which phosphonate-based ILs are confined within the pores of a mesoporous γ-Al2O3 ...ceramic membrane by chemical grafting. The effect of both the chemical nature (i.e., alkyl versus ether) of the organic spacer chain and the presence of phosphonate coupling functions were evidenced as crucial parameters influencing CO2 transport through the membranes. The effectiveness of the grafting procedure yielding GILMs was clearly demonstrated by Fourier transform infrared spectroscopy and high resolution-magic angle spinning NMR, and attractive membrane performance was evidenced through both the CO2/N2 ideal selectivity (∼140) and CO2 permeability (∼130 Barrer).
Rupture of the ovarian follicle releases the oocyte at ovulation, a timed event that is critical for fertilization. It is not understood how the protease activity required for rupture is directed ...with precise timing and localization to the outer surface, or apex, of the follicle. We hypothesized that vasoconstriction at the apex is essential for rupture. The diameter and blood flow of individual vessels and the thickness of the apical follicle wall were examined over time to expected ovulation using intravital multiphoton microscopy. Vasoconstriction of apical vessels occurred within hours preceding follicle rupture in wild-type mice, but vasoconstriction and rupture were absent in Amhr2cre/+SmoM2 mice in which follicle vessels lack the normal association with vascular smooth muscle. Vasoconstriction is not simply a response to reduced thickness of the follicle wall; vasoconstriction persisted in wild-type mice when thinning of the follicle wall was prevented by infusion of protease inhibitors into the ovarian bursa. Ovulation was inhibited by preventing the periovulatory rise in the expression of the vasoconstrictor endothelin 2 by follicle cells of wild-type mice. In these mice, infusion of vasoconstrictors (either endothelin 2 or angiotensin 2) into the bursa restored the vasoconstriction of apical vessels and ovulation. Additionally, infusion of endothelin receptor antagonists into the bursa of wild-type mice prevented vasoconstriction and follicle rupture. Processing tissue to allow imaging at increased depth through the follicle and transabdominal ultrasonography in vivo showed that decreased blood flow is restricted to the apex. These results demonstrate that vasoconstriction at the apex of the follicle is essential for ovulation.
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