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1. 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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2. Metal‐Ligand Cooperativity to Assemble a Neutral and Terminal Niobium Phosphorus Triple Bond (Nb≡P)

   https://doi.org/10.1002/anie.202212488  

   Senthil, Shuruthi; Kwon, Seongyeon; Fehn, Dominik; Im, Hoyoung; Gau, Michael R.; Carroll, Patrick J.; Baik, Mu‐Hyun; Meyer, Karsten; Mindiola, Daniel J. (November 2022, Angewandte Chemie International Edition)

   Abstract Decarbonylation along with P‐atom transfer from the phosphaethynolate anion, PCO⁻, to the Nb^IVcomplex [(PNP)NbCl₂(N^tBuAr)] (1) (PNP=N[2‐PⁱPr₂‐4‐methylphenyl]₂⁻; Ar=3,5‐Me₂C₆H₃) results in its coupling with one of the phosphine arms of the pincer ligand to produce a phosphanylidene phosphorane complex [(PNPP)NbCl(N^tBuAr)] (2). Reduction of2with CoCp*₂cleaves the P−P bond to form the first neutral and terminal phosphido complex of a group 5 transition metal, namely, [(PNP)Nb≡P(N^tBuAr)] (3). Theoretical studies have been used to understand both the coupling of the P‐atom and the reductive cleavage of the P−P bond. Reaction of3with a two‐electron oxidant such as ethylene sulfide results in a diamagnetic sulfido complex having a P−P coupled ligand, namely [(PNPP)Nb=S(N^tBuAr)] (4). 

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3. Synergistic reduction in interfacial flexibility of TREM2 ^R47H and ApoE4 may underlie AD pathology

   https://doi.org/10.1002/alz.70120  

   Lietzke, Emma E; Saeb, David; Aldrich, Emma C; Bruce, Kimberley D; Sprenger, Kayla G (April 2025, Alzheimer's & Dementia)

   Abstract BACKGROUNDThe strongest genetic drivers of late‐onset Alzheimer's disease (AD) are apolipoprotein E4 (ApoE4) and TREM2^R47H. Despite their critical roles, the mechanisms underlying their interactions remain poorly understood. METHODSWe conducted microsecond‐long molecular dynamics simulations of TREM2‐ApoE complexes, including TREM2^R47H, validating our findings through comparison with published experimental data on TREM2‐ApoE binding interactions. RESULTSOur simulations reveal TREM2^WTcan sample an “open” CDR2 conformation, challenging the prevailing notion that this conformation is pathogenic. TREM2^WTexhibits greater flexibility, accessing diverse CDR2 conformations, while rigidity in TREM2^R47H’s CDR2 may explain its reduced ligand‐binding properties. ApoE2 facilitates dynamic reconfiguration of TREM2‐ApoE2 complexes, which is absent with ApoE4. TREM2^R47Hand ApoE4 mutually rigidify each other, suppressing interfacial flexibility. DISCUSSIONOur findings suggest mechanisms underlying ApoE2's neuroprotective functions, ApoE4's pathogenicity, and the synergistic effects of ApoE4 and TREM2^R47Hin AD. TREM2^WT’s flexibility and reconfiguration with ApoE2 may support microglial activation, while rigidity in TREM2^R47H‐ApoE4 interactions may drive pathogenic signaling. HighlightsTREM2^WTsamples diverse CDR2 conformations, challenging prior assumptions that an “open” CDR2 state is solely pathogenic.ApoE2 promotes dynamic reconfiguration of TREM2‐ApoE2 complexes, preserving TREM2^WT's flexibility.ApoE4's hinge forms a unique binding pocket that enhances TREM2 binding.The TREM2^R47H‐ApoE4 complex exhibits mutual rigidity, suppressing CDR2 and hinge flexibility. 

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4. High Levels of Triggering Receptor Expressed in Myeloid Cells-Like Transcript-1 Positive, but Not Glycoprotein 1b+, Microparticles Are Associated With Poor Outcomes in Acute Respiratory Distress Syndrome

   https://doi.org/10.1097/CCE.0000000000001108  

   Gibson, Angelia D; Bayrón-Marrero, Zaida; Nieves-Lopez, Benjamin; Maldonado-Martínez, Gerónimo; Washington, A Valance (January 2024, Critical Care Explorations)

   OBJECTIVES:To identify triggering receptor expressed in myeloid cells-like transcript-1 positive (TLT-1⁺) microparticles (MPs) and evaluate if their presence is associated with clinical outcomes and/or disease severity in acute respiratory distress syndrome (ARDS). DESIGN:Retrospective cohort study. SETTING:ARDS Network clinical trials. PATIENTS:A total of 564 patients were diagnosed with ARDS. INTERVENTIONS:None. MEASUREMENTS AND MAIN RESULTS:Using flow cytometry, we demonstrated the presence of TLT-1⁺platelet-derived microparticles (PMP) that bind fibrinogen in plasma samples from fresh donors. We retrospectively quantified TLT-1, glycoprotein (Gp) 1b, or α_IIbβ_IIIaimmunopositive microparticles in plasma samples from patients with ARDS enrolled in the ARMA, KARMA, and LARMA (Studies 01 and 03 lower versus higher tidal volume, ketoconazole treatment, and lisofylline treatment Clincial Trials) ARDS Network clinical trials and evaluated the relationship between these measures and clinical outcomes. No associations were found between Gp1b⁺MPs and clinical outcomes for any of the cohorts. When stratified by quartile, associations were found for survival, ventilation-free breathing, and thrombocytopenia with α_IIbβ_IIIa⁺and TLT-1⁺MPs (χ²p< 0.001). Notably, 63 of 64 patients in this study who failed to achieve unassisted breathing had TLT⁺PMP in the 75th percentile. In all three cohorts, patients whose TLT⁺MP counts were higher than the median had higher Acute Physiology and Chronic Health Evaluation III scores, were more likely to present with thrombocytopenia and were 3.7 times (p< 0.001) more likely to die than patients with lower TLT⁺PMP after adjusting for other risk factors. CONCLUSIONS:Although both α_IIbβ_IIIa⁺and TLT⁺microparticles (α_IIbβ_IIIa, TLT-1) were associated with mortality, TLT-1⁺MPs demonstrated stronger correlations with Acute Physiology and Chronic Health Evaluation III scores, unassisted breathing, and multiple system organ failure. These findings warrant further exploration of the mechanistic role of TLT-1⁺PMP in ARDS or acute lung injury progression. 

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5. Laser-cooling Cadmium Bosons and Fermions with Near Ultraviolet Triplet Excitations

   https://doi.org/10.1088/1742-6596/2889/1/012006  

   Gibble, Kurt (November 2024, Journal of Physics: Conference Series)

   Abstract Cadmium is laser-cooled and trapped with excitations to triplet states with UVA light, first using only the 67 kHz wide 326 nm intercombination line and subsequently, for large loading rates, the 25 MHz wide 361 nm³P₂→³D₃transition. Eschewing the hard UV 229 nm¹S₀→¹P₁transition, only small magnetic fields gradients, less than 6 G cm⁻¹, are required enabling a 100% transfer of atoms from the 361 nm trap to the 326 nm narrow-line trap. All 8 stable cadmium isotopes are straightforwardly trapped, including two nuclear-spin- $\frac{1}{2}$fermions that require no additional repumping. We observe evidence of³P₂collisions limiting the number of trapped metastable atoms, report isotope shifts for¹¹¹Cd and¹¹³Cd of the 326 nm¹S₀→³P₁, 480nm³P₁→³S₁, and 361 nm³P₂→³D₃transitions, and measure the¹¹⁴Cd 5s5p³P₂→ 5s5d³D₃transition frequency to be 830 096 573(15) MHz. 

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