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Title: Coherent Optical Control of Single Ytterbium Ions in a GaAs Hybrid Photonic Crystal Cavity on Yb:YVO4

We demonstrate coherent optical control of single Yb3+ions in YVO4coupled evanescently to a GaAs photonic crystal cavity.

 
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Award ID(s):
1936350
NSF-PAR ID:
10406105
Author(s) / Creator(s):
; ; ;
Date Published:
Journal Name:
CLEO: QELS_Fundamental Science 2022
Page Range / eLocation ID:
FM5D.4
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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  1. Key points

     Accumulation of inorganic phosphate (Pi) may contribute to muscle fatigue by precipitating calcium salts inside the sarcoplasmic reticulum (SR). Neither direct demonstration of this process nor definition of the entry pathway of Piinto SR are fully established.

     We showed that Pipromoted Ca2+release at concentrations below 10 mmand decreased it at higher concentrations. This decrease correlated well with that of [Ca2+]SR.

     Pre‐treatment of permeabilized myofibres with 2 mmClchannel blocker 9‐anthracenecarboxylic acid (9AC) inhibited both effects of Pi.

     The biphasic dependence of Ca2+release on [Pi] is explained by a direct effect of Piacting on the SR Ca2+release channel, combined with the intra‐SR precipitation of Ca2+salts. The effects of 9AC demonstrate that Pienters the SR via a Clpathway of an as‐yet‐undefined molecular nature.

    Abstract

    Fatiguing exercise causes hydrolysis of phosphocreatine, increasing the intracellular concentration of inorganic phosphate (Pi). Pidiffuses into the sarcoplasmic reticulum (SR) where it is believed to form insoluble Ca2+salts, thus contributing to the impairment of Ca2+release. Information on the Pientrance pathway is still lacking. In amphibian muscles endowed with isoform 3 of the RyR channel, Ca2+spark frequency is correlated with the Ca2+load of the SR and can be used to monitor this variable. We studied the effects of Pion Ca2+sparks in permeabilized fibres of the frog. Relative event frequency (f/fref) rose with increasing [Pi], reaching 2.54 ± 1.6 at 5 mm,and then decreased monotonically, reaching 0.09 ± 0.03 at [Pi] = 80 mm. Measurement of [Ca2+]SRconfirmed a decrease correlated with spark frequency at high [Pi]. A large [Ca2+]SRsurge was observed upon Piremoval. Anion channels are a putative path for Piinto the SR. We tested the effect of the chloride channel blocker 9‐anthracenecarboxylic acid (9AC) on Pientrance. 9AC (400 µm)applied to the cytoplasm produced a non‐significant increase in spark frequency and reduced the Pieffects on this parameter. Fibre treatment with 2 mm9AC in the presence of high cytoplasmic Mg2+suppressed the effects of Pion [Ca2+]SRand spark frequency up to 55 mm[Pi]. These results suggest that chloride channels (or transporters) provide the main pathway of inorganic phosphate into the SR and confirm that Piimpairs Ca2+release by accumulating and precipitating with Ca2+inside the SR, thus contributing to myogenic fatigue.

     
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  2. Abstract

    Self‐sustaining photocatalytic NO3reduction systems could become ideal NO3removal methods. Developing an efficient, highly active photocatalyst is the key to the photocatalytic reduction of NO3. In this work, we present the synthesis of Ni2P‐modified Ta3N5(Ni2P/Ta3N5), TaON (Ni2P/TaON), and TiO2(Ni2P/TiO2). Starting with a 2 mM (28 g/mL NO3−N) aqueous solution of NO3, as made Ni2P/Ta3N5and Ni2P/TaON display as high as 79% and 61% NO3conversion under 419 nm light within 12 h, which correspond to reaction rates per gram of 196 μmol g−1 h−1and 153 μmol g−1 h−1, respectively, and apparent quantum yields of 3–4%. Compared to 24% NO3conversion in Ni2P/TiO2, Ni2P/Ta3N5and Ni2P/TaON exhibit higher activities due to the visible light active semiconductor (SC) substrates Ta3N5and TaON. We also discuss two possible electron migration pathways in Ni2P/semiconductor heterostructures. Our experimental results suggest one dominant electron migration pathway in these materials, namely: Photo‐generated electrons migrate from the semiconductor to co‐catalyst Ni2P, and upshift its Fermi level. The higher Fermi level provides greater driving force and allows NO3reduction to occur on the Ni2P surface.

     
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  3. Abstract

    We evaluate the efficacy of the stable isotope composition of precipitation and plant waxes as proxies for paleoaltimetry and paleohydrology in the northern tropical Andes. We report monthly hydrogen (δ2Hp) and oxygen (δ18Op) isotope values of precipitation for an annual cycle, and hydrogen isotope values of plant waxes (δ2Hwax) obtained from modern soils along the eastern and western flanks of the Eastern Cordillera of Colombia. δ2Hp, δ18Op, as well as the unweighted mean δ2Hwaxvalues ofn‐C29,n‐C31, andn‐C33n‐alkanes in the eastern flank show a dependence on elevation (R2 = 0.90, 0.82, and 0.65, respectively). In stark contrast, the stable isotope compositions of neither precipitation nor plant waxes from the western flank correlate with elevation (R2 < 0.23), on top of a negligible (p‐value >0.05) correlation between δ2Hwaxand δ2Hp. In general, δ2Hwaxvalues along the eastern flank of the Eastern Cordillera seem to follow the trend of a simple Rayleigh distillation process that is consistent with studies elsewhere on the eastern side of the Andes in South America. Neither δ2Hpnor δ18Op, and therefore δ2Hwax, offer reliable estimates of past elevations in the western flank, due perhaps to water vapor source mixing, evaporation overprint, contrasting plant communities, and/or differences in evapotranspiration. Thus, δ2Hwaxis only reliable for paleohydrology and paleoaltimetry reconstructions on the eastern flank of the Andes, whereas interpretations based on δ2Hpand/or δ18Opwest of the highest point of the Eastern Cordillera need to consider mixing of moisture sources in addition to precipitation amount.

     
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  4. Abstract

    Measurements of oxygen and hydrogen stable isotopes in precipitation (δ18OPand δ2HP) provide a valuable tool for understanding modern hydrological processes and the empirical foundation for interpreting paleoisotope archives. However, long‐term data sets of modern δ18OPand δ2HPin southern Alaska are entirely absent, thus limiting our insight and application of regionally defined climate‐isotope relationships in this proxy‐rich region. We present and utilize a 13‐year‐long record of event‐based δ18OPand δ2HPdata from Anchorage, Alaska (2005–2018,n = 332), to determine the mechanisms controlling precipitation isotopes. Local surface air temperature explains ~30% of variability in the δ18OPdata with a temperature‐δ18O slope of 0.31 ‰/°C, indicating that δ18OParchives may not be suitable paleo‐thermometers in this region. Instead, back‐trajectory modeling reveals how winter δ18OP2HPreflects synoptic and mesoscale processes in atmospheric circulation that drive changes in the passage of air masses with different moisture sources, transport, and rainout histories. Specifically, meridional systems—with either northerly flow from the Arctic or southerly flow from the Gulf of Alaska—have relatively low δ18OP2HPdue to progressive cooling and removal of precipitation as it condenses with altitude over Alaska's southern mountain ranges. To the contrary, zonally derived moisture from either the North Pacific and/or Bering Sea retains relatively high δ18OP2HPvalues. These new data contribute a better understanding of the modern Alaska water isotope cycle and provide an empirical basis for interpreting paleoisotope archives in context of regional atmospheric circulation.

     
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  5. Rationale

    Advances in sulfur isotope measurement techniques have led to increased analytical precision. However, accurate measurement of36S remains a challenge. This difficulty arises primarily from unresolved isobaric interferences of36SF5+atm/z = 131 u,186WF42+and12C3F5+, which lead to scale compression. Theoretically, unresolved interference with 2% relative intensity could cause 1‰ underestimation in a sample with real δ36S = +60‰.

    Methods

    Our study develops an interference‐free four‐sulfur isotope measurement method by using the high‐resolution mass spectrometer Panorama. The mass resolving power of Panorama allows the distinction of186WF42+and12C3F5+from36SF5+.

    Results

    The186WF42+relative intensity was initially 9.4% that of36SF5+but reduced to 1.5% through tuning, while12C3F5+relative intensity dropped from 74% to 40% after flushing with air. Three IAEA standards were analyzed with both Panorama and MAT 253. We obtained Δ36SIAEA‐S‐2 = 1.238 ± 0.040‰ and Δ36SIAEA‐S‐3 = −0.882 ± 0.030‰, relative to IAEA‐S‐1, from Panorama, and Δ36SIAEA‐S‐2 = 0.18 ± 0.02‰ and Δ36SIAEA‐S‐3 = 0.11 ± 0.14‰ from MAT 253, while δ34S values from the two instruments are consistent.

    Conclusion

    The measurement discrepancies on36S between Panorama and MAT 253 highlight the impact of scale compression due to unresolved isobaric interferences. Resolving this problem is crucial for accurate36S analysis. We recommend replacing the filament material with rhenium, tuning the filament voltage, and avoiding carbon in instruments to eliminate or mitigate interferences. We propose future systematic efforts to calibrate the δ33S, δ34S, and δ36S of IAEA‐S‐1, IAEA‐S‐2, and IAEA‐S‐3 and advise bracketing all three reference materials in the measurement sequences, to enable calibration.

     
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