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Abstract The methoxy‐ and fluoro‐derivatives ofmeta‐nitrophenylacetic acid (mNPA) chromophores undergo photodecarboxylation with comparable quantum yields (Φ) to unsubstitutedmNPA, but uncage at red‐shifted excitation wavelengths. This observation prompted us to investigate DPAdeCageOMe (2‐[bis(pyridin‐2‐ylmethyl)amino]‐2‐(4‐methoxy‐3‐nitrophenyl)acetic acid) and DPAdeCageF (2‐[bis(pyridin‐2‐ylmethyl)amino]‐2‐(4‐fluoro‐3‐nitrophenyl)acetic acid) as Zn2+photocages. DPAdeCageOMe has a high Φ and exhibits other photophysical properties comparable to XDPAdeCage ({bis[(2‐pyridyl)methyl]amino}(9‐oxo‐2‐xanthenyl) acetic acid), the best preforming Zn2+photocage reported to date. Since the synthesis of DPAdeCageOMe is more straightforward than XDPACage, the new photocage will be a highly competitive tool for biological applications.
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Deconvoluting charge-transfer, mass transfer, and ohmic resistances in phosphonic acid–sulfonic acid ionomer binders used in electrochemical hydrogen pumps
This work reveals how electrode binders affect reaction kinetics, ionic conductivity, and gas transport in electrochemical hydrogen pumps (EHPs). Using a blend of phosphonic acid and perfluorosulfonic acid ionomers as the electrode binder, an EHP was operated at 5 A cm−2.
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- Award ID(s):
- 2143056
- PAR ID:
- 10471067
- Publisher / Repository:
- Royal Society of Chemistry
- Date Published:
- Journal Name:
- Energy & Environmental Science
- ISSN:
- 1754-5692
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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We investigated the relationship between aspartic acid d:l ratios and otolith-derived age estimates in Gulf of Mexico red snapper, Lutjanus campechanus (ages 1–26 years; R2 = 0.89) and Caribbean yellowtail snapper, Ocyurus chrysurus (ages 2–17 years; R2 = 0.84). The estimated racemization rate was 0.61 × 10−3 year−1for red snapper and 1.28 × 10−3 year−1for yellowtail snapper, reflecting temperature differences between study regions. Mean jackknifed error in ages predicted from aspartic acid d:l was 1.70 ± 0.39 years for red snapper and 1.57 ± 0.41 years for yellowtail snapper. Results suggest amino acid racemization may be an effective tool for direct age estimation and potentially age validation in fishes.more » « less
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Summary Patients with neurocognitive disorders often battle sleep disturbances. Kynurenic acid is a tryptophan metabolite of the kynurenine pathway implicated in the pathology of these illnesses. Modest increases in kynurenic acid, an antagonist at glutamatergic and cholinergic receptors, result in cognitive impairments and sleep dysfunction. We explored the hypothesis that inhibition of the kynurenic acid synthesising enzyme, kynurenine aminotransferase II, may alleviate sleep disturbances. At the start of the light phase, adult male and female Wistar rats received systemic injections of either: (i) vehicle; (ii) kynurenine (100 mg kg−1; i.p.); (iii) the kynurenine aminotransferase II inhibitor, PF‐04859989 (30 mg kg−1; s.c.); or (iv) PF‐04859989 and kynurenine in combination. Kynurenine and kynurenic acid levels were evaluated in the plasma and brain. Separate animals were implanted with electroencephalogram and electromyogram telemetry devices to record polysomnography, and evaluate the vigilance states wake, rapid eye movement sleep and non‐rapid eye movement sleep following each treatment. Kynurenine challenge increased brain kynurenic acid and resulted in reduced rapid eye movement sleep duration, non‐rapid eye movement sleep delta power and sleep spindles. PF‐04859989 reduced brain kynurenic acid formation when given prior to kynurenine, prevented disturbances in rapid eye movement sleep and sleep spindles, and enhanced non‐rapid eye movement sleep. Our findings suggest that reducing kynurenic acid in conditions where the kynurenine pathway is activated may serve as a potential strategy for improving sleep dynamics.more » « less
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/D3EE01776A
