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1. New ²⁶ P(p, γ) ²⁷ S Thermonuclear Reaction Rate and Its Astrophysical Implications in the rp-process

   https://doi.org/10.3847/1538-4357/accf9c  

   Hou, S. Q.; Liu, J. B.; Trueman, T. C. L.; Li, J. G.; Pignatari, M.; Bertulani, C. A.; Xu, X. X. (June 2023, The Astrophysical Journal)

   Abstract Accurate nuclear reaction rates for²⁶P(p,γ)²⁷S are pivotal for a comprehensive understanding of therp-process nucleosynthesis path in the region of proton-rich sulfur and phosphorus isotopes. However, large uncertainties still exist in the current rate of²⁶P(p,γ)²⁷S because of the lack of nuclear mass and energy level structure information for²⁷S. We reevaluate this reaction rate using the experimentally constrained²⁷S mass, together with the shell model predicted level structure. It is found that the²⁶P(p,γ)²⁷S reaction rate is dominated by a direct capture reaction mechanism despite the presence of three resonances atE= 1.104, 1.597, and 1.777 MeV above the proton threshold in²⁷S. The new rate is overall smaller than the other previous rates from the Hauser–Feshbach statistical model by at least 1 order of magnitude in the temperature range of X-ray burst interest. In addition, we consistently update the photodisintegration rate using the new²⁷S mass. The influence of new rates of forward and reverse reaction in the abundances of isotopes produced in therp-process is explored by postprocessing nucleosynthesis calculations. The final abundance ratio of²⁷S/²⁶P obtained using the new rates is only 10% of that from the old rate. The abundance flow calculations show that the reaction path²⁶P(p,γ)²⁷S(β⁺,ν)²⁷P is not as important as previously thought for producing²⁷P. The adoption of the new reaction rates for²⁶P(p,γ)²⁷S only reduces the final production of aluminum by 7.1% and has no discernible impact on the yield of other elements. 

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2. Quantifying Soil Phosphorus Dynamics: A Data Assimilation Approach

   https://doi.org/10.1029/2018JG004903  

   Hou, Enqing; Lu, Xingjie; Jiang, Lifen; Wen, Dazhi; Luo, Yiqi (July 2019, Journal of Geophysical Research: Biogeosciences)

   Abstract The dynamics of soil phosphorus (P) control its bioavailability. Yet it remains a challenge to quantify soil P dynamics. Here we developed a soil P dynamics (SPD) model. We then assimilated eight data sets of 426‐day changes in Hedley P fractions into the SPD model, to quantify the dynamics of six major P pools in eight soil samples that are representative of a wide type of soils. The performance of our SPD model was better for labile P, secondary mineral P, and occluded P than for nonoccluded organic P (Po) and primary mineral P. All parameters describing soil P dynamics were approximately constrained by the data sets. The average turnover rates were labile P 0.040 g g⁻¹day⁻¹, nonoccluded Po 0.051 g g⁻¹day⁻¹, secondary mineral P 0.023 g g⁻¹day⁻¹, primary mineral P 0.00088 g g⁻¹day⁻¹, occluded Po 0.0066 g g⁻¹day⁻¹, and occluded inorganic P 0.0065 g g⁻¹day⁻¹, in the greenhouse environment studied. Labile P was transferred on average more to nonoccluded Po (transfer coefficient of 0.42) and secondary mineral P (0.38) than to plants (0.20). Soil pH and organic C concentration were the key soil properties regulating the competition for P between plants and soil secondary minerals. The turnover rate of labile P was positively correlated with that of nonoccluded Po and secondary mineral P. The pool size of labile P was most sensitive to its turnover rate. Overall, we suggest data assimilation can contribute significantly to an improved understanding of soil P dynamics. 

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3. Thermonuclear ²⁸ P(p, γ ) ²⁹ S reaction rate and astrophysical implication in ONe nova explosion

   https://doi.org/10.1051/0004-6361/202449536  

   Liu, J B; José, J; Hou, S Q; Pignatari, M; Trueman, T_C L; Longland, R; Li, J G; Bertulani, C A; Xu, X X (July 2024, Astronomy & Astrophysics)

   Context.An accurate²⁸P(p,γ)²⁹S reaction rate is crucial to defining the nucleosynthesis products of explosive hydrogen burning in ONe novae. Using the recently released nuclear mass of²⁹S, together with a shell model and a direct capture calculation, we reanalyzed the²⁸P(p,γ)²⁹S thermonuclear reaction rate and its astrophysical implication. Aims.We focus on improving the astrophysical rate for²⁸P(p,γ)²⁹S based on the newest nuclear mass data. Our goal is to explore the impact of the new rate and associated uncertainties on the nova nucleosynthesis. Methods.We evaluated this reaction rate via the sum of the isolated resonance contribution instead of the previously used Hauser-Feshbach statistical model. The corresponding rate uncertainty at different energies was derived using a Monte Carlo method. Nova nucleosynthesis is computed with the 1D hydrodynamic code SHIVA. Results.The contribution from the capture on the first excited state at 105.64 keV in²⁸P is taken into account for the first time. We find that the capture rate on the first excited state in²⁸P is up to more than 12 times larger than the ground-state capture rate in the temperature region of 2.5 × 10⁷K to 4 × 10⁸K, resulting in the total²⁸P(p,γ)²⁹S reaction rate being enhanced by a factor of up to 1.4 at ~1 × 10⁹K. In addition, the rate uncertainty has been quantified for the first time. It is found that the new rate is smaller than the previous statistical model rates, but it still agrees with them within uncertainties for nova temperatures. The statistical model appears to be roughly valid for the rate estimation of this reaction in the nova nucleosynthesis scenario. Using the 1D hydrodynamic code SHIVA, we performed the nucleosynthesis calculations in a nova explosion to investigate the impact of the new rates of²⁸P(p,γ)²⁹S. Our calculations show that the nova abundance pattern is only marginally affected if we use our new rates with respect to the same simulations but statistical model rates. Finally, the isotopes whose abundance is most influenced by the present²⁸P(p,γ)²⁹S uncertainty are²⁸Si,^33,34S,^35,37Cl, and³⁶Ar, with relative abundance changes at the level of only 3% to 4%. 

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4. Synthesis of 5‐Cyanomethyluridine (cnm ⁵ U) and 5‐Cyanouridine (cn ⁵ U) Phosphoramidites and Their Incorporation into RNA Oligonucleotides

   https://doi.org/10.1002/cpnc.114  

   Mao, Song; Tsai, Hsu‐Chun; Sheng, Jia (August 2020, Current Protocols in Nucleic Acid Chemistry)

   Abstract This article contains detailed synthetic protocols for preparation of 5‐cyanomethyluridine (cnm⁵U) and 5‐cyanouridine (cn⁵U) phosphoramidites. The synthesis of the cnm⁵U phosphoramidite building block starts with commercially available 5‐methyluridine (m⁵C), followed by bromination of the 5‐methyl group to install the cyano moiety using TMSCN/TBAF. The cn⁵U phosphoramidite is obtained by regular Vorbrüggen glycosylation of the protected ribofuranose with silylated 5‐cyanouracil. These two modified phosphoramidites are suitable for synthesis of RNA oligonucleotides on solid phase using conventional amidite chemistry. Our protocol provides access to two novel building blocks for constructing RNA‐based therapeutics. © 2020 Wiley Periodicals LLC. Basic Protocol 1: Preparation of cnm⁵U and cn⁵U phosphoramidites Basic Protocol 2: Synthesis, purification, and characterization of cnm⁵U‐ and cn⁵U‐modified RNA oligonucleotides 

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5. Spectroscopic study of the 4f ⁷ 6s ^{2 8} S 7/2∘ – 4f ⁷ ( ⁸ S ^° ) 6s6p( ¹ P ^° ) ⁸ P _5/2,7/2 transitions in neutral europium-151 and europium-153: absolute frequency and hyperfine structure

   https://doi.org/10.1364/JOSAB.521181  

   Maruko, C.; Çölmek, N_N; Herd, M_T; Ahrendsen, K_J; Cabrales, B.; Cannon, G.; Davis, E.; Guo, X_Y; Karani, T.; Wallace, A.; et al (April 2024, Journal of the Optical Society of America B)

   We report on spectroscopic measurements on the 4f⁷6s²⁸S_7/2^∘−4f⁷(⁸S^∘)6s6p(¹P^∘)⁸P_5/2,7/2transitions at 466.32 nm and 462.85 nm, respectively, in neutral europium-151 and europium-153. The center of gravity frequencies for the 151 and 153 isotopes for both transitions are reported for the first time using saturated absorption spectroscopy. For the 6s6p(¹P^∘)⁸P_5/2state, the center of gravity frequencies were found to be 642,894,493.3(4) MHz and 642,891,693.3(9) MHz for the 151 and 153 isotopes, respectively. The hyperfine constants for the upper state were found to beA(151)=−157.01(3)MHz,B(151)=74.5(4)MHz andA(153)=−69.43(14)MHz,B(153)=191.0(26)MHz. These hyperfine values are all consistent with previously published results except forB(151) that has a small discrepancy. The isotope shift was found to be 2799.54(20) MHz, a small discrepancy with previously published results. For the 6s6p(¹P^∘)⁸P_7/2state, the center of gravity frequencies were found to be 647,708,930.6(6) MHz and 647,705,958.4(26) MHz for the 151 and 153 isotopes, respectively. The hyperfine constants for the upper state were found to beA(151)=−218.66(4)MHz,B(151)=−293.4(8)MHz andA(153)=−97.15(13)MHz,B(153)=−750(3)MHz. These values are all consistent with previously published results except forA(151) that has a small discrepancy. The isotope shift was found to be 2972.8(5) MHz, a small discrepancy with previously measured results. 

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