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1. Reduced global plant respiration due to the acclimation of leaf dark respiration coupled with photosynthesis

   https://doi.org/10.1111/nph.19355  

   Ren, Yanghang; Wang, Han; Harrison, Sandy_P; Prentice, I_Colin; Atkin, Owen_K; Smith, Nicholas_G; Mengoli, Giulia; Stefanski, Artur; Reich, Peter_B (October 2023, New Phytologist)

   Summary Leaf dark respiration (R_d) acclimates to environmental changes. However, the magnitude, controls and time scales of acclimation remain unclear and are inconsistently treated in ecosystem models.We hypothesized thatR_dand Rubisco carboxylation capacity (V_cmax) at 25°C (R_d,25,V_cmax,25) are coordinated so thatR_d,25variations supportV_cmax,25at a level allowing full light use, withV_cmax,25reflecting daytime conditions (for photosynthesis), andR_d,25/V_cmax,25reflecting night‐time conditions (for starch degradation and sucrose export). We tested this hypothesis temporally using a 5‐yr warming experiment, and spatially using an extensive field‐measurement data set. We compared the results to three published alternatives:R_d,25declines linearly with daily average prior temperature;R_dat average prior night temperatures tends towards a constant value; andR_d,25/V_cmax,25is constant.Our hypothesis accounted for more variation in observedR_d,25over time (R² = 0.74) and space (R² = 0.68) than the alternatives. Night‐time temperature dominated the seasonal time‐course ofR_d, with an apparent response time scale ofc.2 wk.V_cmaxdominated the spatial patterns.Our acclimation hypothesis results in a smaller increase in globalR_din response to rising CO₂and warming than is projected by the two of three alternative hypotheses, and by current models. 

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2. Development of electrophysiological and morphological properties of human embryonic stem cell-derived GABAergic interneurons at different times after transplantation into the mouse hippocampus

   https://doi.org/doi: 10.1371/journal.pone.0237426  

   Shrestha, S; Anderson, N; Grabel, L; Aaron, G. (January 2020, PloS one)

   null (Ed.)

   Transplantation of human embryonic stem cell (hESC)-derived neural progenitors is a potential treatment for neurological disorders, but relatively little is known about the time course for human neuron maturation after transplantation and the emergence of morphological and electrophysiological properties. To address this gap, we transplanted hESC-derived human GABAergic interneuron progenitors into the mouse hippocampus, and then characterized their electrophysiological properties and dendritic arborizations after transplantation by means of ex vivo whole-cell patch clamp recording, followed by biocytin staining, confocal imaging and neuron reconstruction software. We asked whether particular electrophysiological and morphological properties showed maturation-dependent changes after transplantation. We also investigated whether the emergence of particular electrophysiological properties were linked to increased complexity of the dendritic arbors. Human neurons were classified into five distinct neuronal types (Type I-V), ranging from immature to mature fastspiking interneurons. Hierarchical clustering of the dendritic morphology and Sholl analyses suggested four morphologically distinct classes (Class A-D), ranging from simple/immature to highly complex. Incorporating all of our data regardless of neuronal classification, we investigated whether any electrophysiological and morphological features correlated with time post-transplantation. This analysis demonstrated that both dendritic arbors and electrophysiological properties matured after transplantation. 

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3. Synthesis, structures, and reactivity of isomers of [RuCp*(1,4-(Me ₂ N) ₂ C ₆ H ₄ )] ₂

   https://doi.org/10.1039/D1DT02155A  

   Longhi, Elena; Risko, Chad; Bacsa, John; Khrustalev, Victor; Rigin, Sergei; Moudgil, Karttikay; Timofeeva, Tatiana V.; Marder, Seth R.; Barlow, Stephen (September 2021, Dalton Transactions)

   [RuCp*(1,3,5-R 3 C 6 H 3 )] 2 {Cp* = η 5 -pentamethylcyclopentadienyl, R = Me, Et} have previously been found to be moderately air stable, yet highly reducing, with estimated D + /0.5D 2 (where D 2 and D + represent the dimer and the corresponding monomeric cation, respectively) redox potentials of ca. −2.0 V vs. FeCp 2 +/0 . These properties have led to their use as n-dopants for organic semiconductors. Use of arenes substituted with π-electron donors is anticipated to lead to even more strongly reducing dimers. [RuCp*(1-(Me 2 N)-3,5-Me 2 C 6 H 3 )] + PF 6 − and [RuCp*(1,4-(Me 2 N) 2 C 6 H 4 )] + PF 6 − have been synthesized and electrochemically and crystallographically characterized; both exhibit D + /D potentials slightly more cathodic than [RuCp*(1,3,5-R 3 C 6 H 3 )] + . Reduction of [RuCp*(1,4-(Me 2 N) 2 C 6 H 4 )] + PF 6 − using silica-supported sodium–potassium alloy leads to a mixture of isomers of [RuCp*(1,4-(Me 2 N) 2 C 6 H 4 )] 2 , two of which have been crystallographically characterized. One of these isomers has a similar molecular structure to [RuCp*(1,3,5-Et 3 C 6 H 3 )] 2 ; the central C–C bond is exo , exo , i.e. , on the opposite face of both six-membered rings from the metals. A D + /0.5D 2 potential of −2.4 V is estimated for this exo , exo dimer, more reducing than that of [RuCp*(1,3,5-R 3 C 6 H 3 )] 2 (−2.0 V). This isomer reacts much more rapidly with both air and electron acceptors than [RuCp*(1,3,5-R 3 C 6 H 3 )] 2 due to a much more cathodic D 2 ˙ + /D 2 potential. The other isomer to be crystallographically characterized, along with a third isomer, are both dimerized in an exo , endo fashion, representing the first examples of such dimers. Density functional theory calculations and reactivity studies indicate that the central bonds of these two isomers are weaker than those of the exo , exo isomer, or of [RuCp*(1,3,5-R 3 C 6 H 3 )] 2 , leading to estimated D + /0.5D 2 potentials of −2.5 and −2.6 V vs. FeCp 2 +/0 . At the same time the D 2 ˙ + /D 2 potentials for the exo , endo dimers are anodically shifted relative to those of [RuCp*(1,3,5-R 3 C 6 H 3 )] 2 , resulting in much greater air stability than for the exo , exo isomer. 

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4. Profiles of MBL Cloud and Drizzle Microphysical Properties Retrieved From Ground‐Based Observations and Validated by Aircraft In Situ Measurements Over the Azores

   https://doi.org/10.1029/2019JD032205  

   Wu, Peng; Dong, Xiquan; Xi, Baike; Tian, Jingjing; Ward, Dale M. (May 2020, Journal of Geophysical Research: Atmospheres)

   Abstract The profiles of marine boundary layer (MBL) cloud and drizzle microphysical properties are important for studying the cloud‐to‐rain conversion and growth processes in MBL clouds. However, it is challenging to simultaneously retrieve both cloud and drizzle microphysical properties within an MBL cloud layer using ground‐based observations. In this study, methods were developed to first decompose drizzle and cloud reflectivity in MBL clouds from Atmospheric Radiation Measurement cloud radar reflectivity measurements and then simultaneously retrieve cloud and drizzle microphysical properties during the Aerosol and Cloud Experiments in the Eastern North Atlantic (ACE‐ENA) campaign. These retrieved microphysical properties, such as cloud and drizzle particle size (r_candr_m,d), their number concentration (N_candN_d) and liquid water content (LWC_candLWC_d), have been validated by aircraft in situ measurements during ACE‐ENA (~158 hr of aircraft data). The mean surface retrieved (in situ measured)r_c,N_c, andLWC_care 10.9 μm (11.8 μm), 70 cm⁻³(60 cm⁻³), and 0.21 g m⁻³(0.22 g m⁻³), respectively. For drizzle microphysical properties, the retrieved (in situ measured)r_d,N_d, andLWC_dare 44.9 μm (45.1 μm), 0.07 cm⁻³(0.08 cm⁻³), and 0.052 g m⁻³(0.066 g m⁻³), respectively. Treating the aircraft in situ measurements as truth, the estimated median retrieval errors are ~15% forr_c, ~35% forN_c, ~30% forLWC_candr_d, and ~50% forN_dandLWC_d. The findings from this study will provide insightful information for improving our understanding of warm rain processes, as well as for improving model simulations. More studies are required over other climatic regions. 

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5. Updated Planetary Mass Constraints of the Young V1298 Tau System Using MAROON-X

   https://doi.org/10.3847/1538-3881/acc865  

   Sikora, James; Rowe, Jason; Barat, Saugata; Bean, Jacob_L; Brady, Madison; Désert, Jean-Michel; Feinstein, Adina_D; Gilbert, Emily_A; Henry, Gregory; Kasper, David; et al (May 2023, The Astronomical Journal)

   Abstract The early K-type T-Tauri star, V1298 Tau (V= 10 mag, age ≈ 20–30 Myr) hosts four transiting planets with radii ranging from 4.9 to 9.6R_⊕. The three inner planets have orbital periods of ≈8–24 days while the outer planet’s period is poorly constrained by single transits observed with K2 and the Transiting Exoplanet Survey Satellite (TESS). Planets b, c, and d are proto–sub-Neptunes that may be undergoing significant mass loss. Depending on the stellar activity and planet masses, they are expected to evolve into super-Earths/sub-Neptunes that bound the radius valley. Here we present results of a joint transit and radial velocity (RV) modeling analysis, which includes recently obtained TESS photometry and MAROON-X RV measurements. Assuming circular orbits, we obtain a low-significance (≈2σ) RV detection of planet c, implying a mass of ${19.8}_{-8.9}^{+9.3}{M}_{\oplus }$and a conservative 2σupper limit of <39M_⊕. For planets b and d, we derive 2σupper limits ofM_b< 159M_⊕andM_d< 41M_⊕, respectively. For planet e, plausible discrete periods ofP_e> 55.4 days are ruled out at the 3σlevel while seven solutions with 43.3 <P_e/d< 55.4 are consistent with the most probable 46.768131 ± 000076 days solution within 3σ. Adopting the most probable solution yields a 2.6σRV detection with a mass of 0.66 ± 0.26M_Jup. Comparing the updated mass and radius constraints with planetary evolution and interior structure models shows that planets b, d, and e are consistent with predictions for young gas-rich planets and that planet c is consistent with having a water-rich core with a substantial (∼5% by mass) H₂envelope. 

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