Late Transition Research Articles

TET2 regulates early and late transitions in exhausted CD8+ T cell differentiation and limits CAR T cell function.

CD8+ T cell exhaustion hampers control of cancer and chronic infections and limits chimeric antigen receptor (CAR) T cell efficacy. Targeting TET2 in CAR T cells provides therapeutic benefit; however, TET2's role in exhausted T cell (TEX) development is unclear. In chronic lymphocytic choriomeningitis virus (LCMV) infection, TET2 drove conversion from stem cell-like TEX progenitors toward terminally differentiated and effector (TEFF)-like TEX. TET2 also enforced a terminally differentiated state in the early bifurcation between TEFF and TEX, indicating broad roles for TET2 in acquisition of effector biology. To exploit the therapeutic potential of TET2, we developed clinically actionable TET2-targeted CAR T cells by disrupting TET2 via knock-in of a safety switch alongside CAR knock-in at the TRAC locus. TET2-targeted CAR T cells exhibited restrained terminal exhaustion in vitro and enhanced antitumor responses in vivo. Thus, TET2 regulates fate transitions in TEX differentiation and can be targeted with a safety mechanism in CAR T cells for improved tumor control.

Tailoring Superatomic Stability with Transition Metals in Silicon Cages: Shrinking to M@Si15 (M = Re, Os, Ir).

The design of materials with intriguing electronic properties is crucial for advancing nanoscale technologies, where precise control over atomic structure and electronic behavior is essential. Metal-encapsulating silicon cage superatoms (SAs) provide a new paradigm for molecular-scale material design, allowing fine-tuning of both structure and electronic characteristics. The formation of superatoms mimicking halogens, noble gases, and alkali metals has been well-studied, particularly with M@Si16, where early transition metals from groups 3 to 5 stabilize within a Si16 cage, achieving a 68-electron configuration. For late transition metals with excess electrons, a Si15 cage offers enhanced stability by fulfilling the 68-electron rule with one fewer Si atom. This research synthesizes Si15 cage-SAs with rhenium (Re) from group 7 and iridium (Ir) from group 9 on p-type and n-type organic substrates. The stability of Re@Si15 and Ir@Si15 is evaluated via oxidative reactivity with X-ray photoelectron spectroscopy and theoretical calculations, including osmium (Os) from group 8. Re@Si15-, Os@Si150, and Ir@Si15+ exhibit superatomic behaviors similar to halogens, noble gases, and alkali metals due to the 68-electron shell closure. Among them, Re@Si15- on p-type organic substrates shows superior electronic and geometric properties. These findings advance our understanding of M@Sin systems for transition metals, addressing longstanding questions about their properties at n = 15 and 16.

Severe Hyperandrogenism in 46,XX Congenital Adrenal Hyperplasia: Molecular Physiopathology, Late Diagnoses, and Personalized Management.

Congenital Adrenal Hyperplasia (CAH) is a group of autosomal recessive endocrine disorders characterized by alteration in adrenal hormonal secretions. The most common form is caused by CYP21A2 mutations that result in 21-hydroxylase deficiency. Clinical features can vary, from salt-wasting forms, characterized by a lack of mineralocorticoid activity with a risk of perinatal-onset adrenal crises, to "simple-virilizing" forms with sufficient aldosterone secretion, up to milder "non-classical" forms, with a variable grade of hyperandrogenism but no severe hormonal deficiencies. During pregnancy, CAH 46,XX fetuses are exposed to elevated androgen levels, leading to a variable grade of virilization and potential central nervous system effects if untreated. These patients are usually (but not always) assigned female at birth, but some cases may be misdiagnosed and assigned male, potentially inducing fertility, gender identity, and sexual behavior issues in adulthood. In these patients, the benefits and risks of a late gender transition should be carefully evaluated. In this paper, we reviewed the literature concerning the most interesting peculiarities of these conditions.

Transcriptome Analyses at Specific Plastochrons Reveal Timing and Involvement of Phytosulfokine in Maize Vegetative Phase Change

Successive developmental stages of representative early and late juvenile, transition, and adult maize leaves were compared using machine-learning-aided analyses of gene expression patterns to characterize vegetative phase change (VPC), including identification of the timing of this developmental transition in maize. We used t-SNE to organize 32 leaf samples into 9 groups with similar patterns of gene expression. oposSOM yielded clusters of co-expressed genes from key developmental stages. TO-GCN supported a sequence of events in maize in which germination-associated ROS triggers a JA response, both relieving oxidative stress and inducing miR156 production, which in turn spurs juvenility. Patterns of expression of MIR395, which regulates sulfur assimilation, led to the hypothesis that phytosulfokine, a sulfated peptide, is involved in the transition to adult patterns of differentiation.

Electronic Structures of Late versus Early Transition Metal Imido Complexes from 15N‐NMR Signatures

AbstractImido ligand is a ubiquitous motif in organometallic chemistry, serving roles spanning from ancillary ligands to reactive sites. The nature of M=N bond is highly depended on the metal centres and their d‐electron configuration, with late transition metal (TM) imido complexes exhibiting contrasting features when compared to their early TM analogues. Envisioning to uncover general electronic descriptor for the nature of imido ligands, we computationally investigate the solid‐state 15N NMR signatures of late TM imido complexes with various central metals, geometries and d‐electron counts, and compare them against these of the corresponding early TM systems. The spectroscopic signatures are mostly driven by the presence of filled, π‐symmetry orbitals in late TM imido complexes, suggesting the development of high‐lying π(M=N) and low‐lying σ/σ*(M=N) orbitals. This contrasts with what is observed for the reported early TM systems, for which high‐lying σ‐type orbitals determine the NMR signature. Noteworthily, Ni‐ and Pd‐imido complexes with formal d10 configurations exhibit highly asymmetric nitrogen‐15 NMR signature with extremely deshielded principal components, because of the presence of filled, high‐lying antibonding π*(M=N) orbitals, consistent with their high reactivity. The sensitive response of 15N NMR signature to the nature of metal sites further highlights that chemical shift is a useful reactivity descriptor.

Propagation behavior of wetting front and its fluctuation characteristics during subcooled jet impingement quenching

Jet impingement quenching as one of the most effective cooling methods is widely applied in many industrial fields. When a subcooled jet strikes the hot surface, the wetting front propagates outside after the wetting delay accompanied by high-frequency fluctuations. To elucidate the propagation behavior of the wetting front and its fluctuation characteristics, the quenching experiments that an upward water jet with different velocities and subcoolings impacted onto a hot nickel block with an initial temperature of 280°C were conducted. The transient transition boiling associated with the intermittent wet and dry situations around the wetting front was quantitatively analyzed based on the visual observation and fast response surface temperature measurement technique. The liquid-solid contact period near the wetting front, under the late transition boiling regime, spans the range of 494–590 µs. This time interval is comparable to the period of disturbance waves induced by the Plateau-Rayleigh instability of the jet. Furthermore, fluctuation amplitude of the wetting front diminishes from 0.8 to 0.2 mm as it propagates. The order of magnitude and the trend of variation in the fluctuation amplitude with respect to the wetting front radius align with theoretical calculations without considering boiling heat transfer effects.

Late Transition Metal Olefin Polymerization Catalysts Derived from 8-Arylnaphthylamines

Late transition metal catalysts represent a significant class of olefin polymerization catalysts that have played an essential role in advancing the polyolefin industry owing to their highly tunable ligands and low oxophilicity. A key feature for the design of late transition metal catalysts lies in the steric bulk of the o-aryl substituents. Bulky 8-arylnaphthylamines have emerged as a promising aniline candidate for conducting high-performance catalysts by introducing axially steric hindrance around the metal center. This review focuses on late transition metal (Ni, Pd, Fe) catalysts derived from 8-arylnaphthylamines, surveying their synthesis, structural features, and catalytic applications in olefin (co)polymerizations. Additionally, the relationship between catalyst structure and catalytic performance is discussed, highlighting how these unique ligand systems influence polymerization activity, molecular weight, and polymer branching.

Deconvoluting the Role of Electrostatics in Metal Carbonyl Bonding: Dipole Moments and Energy Decomposition Analysis of Late Transition Metal Pincer Complexes

Deconvoluting the Role of Electrostatics in Metal Carbonyl Bonding: Dipole Moments and Energy Decomposition Analysis of Late Transition Metal Pincer Complexes

Structural and energetic properties of cluster models of anatase-supported single late transition metal atoms: a density functional theory benchmark study.

Single-atom catalytic systems constitute an intriguing research topic due to their inherently different chemical behavior as compared to classic heterogeneous catalysts. In this study, cluster systems representing single late transition metal atoms adsorbed on anatase were constructed starting from previously generated periodic models and subjected to a density functional theory (DFT) benchmark study. The ability of different density functional approximations representing all rungs of the Jacob's Ladder classification to accurately describe bond lengths and adsorption energies was assessed for these clusters with the aim of revealing the functional that allows to retain the structural characteristics of the initial periodic system, while also delivering reliable energetics. In this regard, our results indicate that optimisation of the clusters with the meta-GGA functionals TPSS or RevTPSS provides the lowest mean unsigned error and root-mean-square deviations with respect to the periodic models. Moreover, these functionals and, to a slightly lesser degree, PW91 were also found to provide adsorption energies that are statistically the least deviating from the CCSD(T) reference data. More complex hybrid functionals appear to be performing less well. Cluster geometries were determined at the Kohn-Sham DFT level using the LANL2DZ basis set for the transition metals and the Pople 6-31G(d) basis set for O and H. The density functional approximations considered were SVWN, PBE, BP86, BLYP, PW91, TPSS, RevTPSS, M06L, M11L, B3LYP, PBE0, M06, M06-2X, MN15, ωB97X-D, CAM-B3LYP, M11, and MN12-SX. Reference adsorption energies of the metals on the support cluster were obtained at the CCSD(T)/LANL2TZ (transition metals)/6-311 + + G(d,p)//RevTPSS/LANLD2DZ (transition metals)/6-31G*. Besides the above-mentioned functionals, energy calculations using the double-hybrid functionals, DSDPBEP86, PBE0-DH, and B2PLYP, were also performed. All adsorption energy calculations were carried out on the RevTPSS geometries.

Machine Learning-Enhanced Screening of Single-Atom Alloy Clusters for Nitrogen Reduction Reaction.

The electrochemical nitrogen reduction reaction (eNRR) under ambient conditions is a promising method to generate ammonia (NH3), a crucial precursor for fertilizers and chemicals, without carbon emissions. Single-atom alloy catalysts (SAACs) have reinvigorated catalytic processes due to their high activity, selectivity, and efficient use of active atoms. Here, we employed density functional theory (DFT) calculations integrated with machine learning (ML) to investigate dodecahedral nanocluster-based SAACs for analyzing structure-activity relationships in eNRR. Over 300 nanocluster-based SAACs were screened with all the transition metals as dopants to develop an ML model predicting stability and catalytic performance. Facet sites were identified as optimal doping positions, particularly with late group transition metals showing superior stability and activity. Utilizing DFT+ML, we identified 8 highly suitable SAACs for eNRR. Interestingly, the number of valence d-electrons in dopants proved crucial in screening for eNRR activity. These catalysts exhibited low activity in hydrogen evolution reaction, further enhancing their suitability for eNRR. This successful ML-driven approach accelerates catalyst design and discovery, holding significant practical implications.

Interaction of Nitric Oxide with Late 3d Transition Metals: Dissociation and Metal Oxidation

Interaction of Nitric Oxide with Late 3d Transition Metals: Dissociation and Metal Oxidation

Effect of impurities on hydrogen defect stability and migration barrier in yttrium dihydride crystal

The impurity or alloying atoms in YH2 can alter the local electronic structure and so the hydrogen defect stability, as well as the H migration barrier energy. Thus, DFT calculations were employed to determine the effect of foreign elements from alkali and alkaline earth metals to transition metals and one critical impurity element, O, on H vacancy stability and retention characteristics in YH2. Results revealed that alloying elements act as hydrogen vacancy sinks by reducing the vacancy formation energy at neighboring sites. The implantation of non-magnetic foreign elements (s1, s2, and d10 valence electrons) in hydrogen energy landscape was calculated to be minor; while the hydrogen vacancy formation energy was reduced from 1.37 eV to 1.00 eV, the migration energy barrier of hydrogen was increased from 0.87 eV to 1.15 eV for non-magnetic foreign elements. The migration energy barrier monotonically decreased with increasing d-shell occupancy, reaching as low as 0.4 eV for Cr, Mo(d4), and Fe (d4). Alloying with late transition metals (d8 and d9) moderately impacted the hydrogen vacancy formation. Finally, it was found to be O addition into the YH2- lattice did not alter the energy landscape of hydrogen vacancies. Since alloyed YH2 has not been studied extensively, this study provides an atomistic understanding how alloying elements and impurities trap vacancies and affects hydrogen mobility YH2. Meanwhile, the main findings of this study may serve as guidelines for introducing alloying elements in ZrH2 as well.

Hydrogenation Studies of Iridium Pyridine Diimine Complexes with O- and S-Donor Ligands (Hydroxido, Methoxido and Thiolato)

For square-planar late transition metal pyridine, diimine (Rh, Ir) complexes with hydro-xido, methoxido, and thiolato ligands. We could previously establish sizable metal-O- and S π-bonding interactions. Herein, we report the hydrogenation studies of iridium hydroxido and methoxido complexes, which quantitatively lead to the trihydride compound and water/methanol. The iridium trihydride displays a highly fluctional structure with scrambling hydrogen atoms, which can be described as a dihydrogen hydride system based on NMR and DFT investigations. This contrasts the iridium sulfur compounds, which are not reacting with dihydrogen. According to DFT and LNO-CCSD(T) calculations, hydrogenation of the methoxido complex proceeds by a two-step mechanism, i.e., an oxidative addition step of H2 to an Ir(III) dihydride intermediate with consecutive reductive O-H elimination of methanol. Based on PNO-CCSD(T) calculations, the reactivity difference between the O- and S-donors can be traced to the stronger H-O bonds in the water/methanol products compared to the S-H bonds in the sulphur congeners, which serves as a driving force for hydrogenation.

Changes in soils and terrestrial landscapes of the Appalachian Basin (Conemaugh, Monongahela, and Dunkard groups), U.S.A., at the onset of the late Paleozoic climate transition

ABSTRACT Changes in global climate from the Late Pennsylvanian to early Permian resulting from the destabilization of ice sheets in the Southern Hemisphere had important effects on terrestrial landscapes around the Paleozoic world. In the northern Appalachian Basin (U.S.A.), evidence for this transition and its effects on terrestrial systems is preserved in numerous paleosols in the Conemaugh, Monongahela, and Dunkard groups that formed in various alluvial environments. Several studies along a 50 km west–east and 40 km north–south transect through southeast Ohio and southwest West Virginia resulted in the recognition of 24 different pedotypes. An up-section shift in pedotypes from Argillisols to Vertisols and Calcisols as well as an overall upward increase in the diversity of pedotypes records a significant change in soil-forming processes and landscapes. The landscapes of the Late Pennsylvanian were largely characterized by well-developed, clay-rich Alfisols of woodland ecosystems on distal floodplains bordered by poorly developed Inceptisols of early successional or marshland ecosystems on proximal floodplains. By the early Permian, these landscapes began to experience strongly seasonal climates and increasingly prolonged dry periods, resulting in the production of pronounced shrink–swell features and well-developed carbonate horizons. These landscapes were characterized by Vertisols and Inceptisols of highly heterogeneous brakeland ecosystems, with rapid changes in sedimentation, hydrology, and vegetation over short distances. Climatic conditions were prone to fluctuations between wet and dry states during the transition, resulting in a highly heterogeneous landscape that changed significantly through time.

Geological characteristics and seismic identification of reservoirs in the Colorado Basin off the Atlantic coast of Argentina

Abstract The Colorado Basin is a hot exploration frontier basin conjugated with the southwest coast of Africa which has undergone four evolutionary stages: Carboniferous-Jurassic pre-rift, Jurassic-Early Cretaceous rift, Late Cretaceous transition and passive marginal drift since Paleocene. Major oil and gas discoveries have been made in the conjugated Orange Basin in recent years, including the Graff field and Venus field discovered in 2022 with recoverable reserves of 550 Mboe and 2.3 Bboe, respectively. This indicates that the basin has good oil and gas exploration potential. Based on the analysis of drilling data and seismic data, it is concluded that the basin has a mature oil-gas generation system and better reservoir conditions. The pre-rift and syn-rift source rocks are confirmed by 5 Wells with oil and gas shows in the shallow water shelf, and all have entered the hydrocarbon generation threshold. Reservoir distribution and trap-sealing conditions have become key factors in oil and gas exploration. this paper describes the reservoir characteristics in the drilling data, and extrapolates the seismic reflection characteristics of the same strata, and predicts the reservoir distribution in the unexplored area of the basin. The reservoir lithology and sedimentary facies are analyzed based on the gamma logging curves. Reservoir identification and reasonable prediction on seismic profile are mainly determined by seismic reflection amplitude and horizon calibration. The basin has three sets of reservoirs, namely, pre-rift Permian underwater fan sandstone, Lower Cretaceous alluvial fan sandstone of syn-rift period and Upper Cretaceous Colorado Formation shallow marine sandstone of transitional period. Among them, Colorado Formation sandstone reservoir has the best physical property conditions, with a maximum porosity of 32% and a thickness of 1000m. The Cretaceous and Paleogene turbidite sandstone of slope fan facies are potential reservoir in the deep waters, which mainly form litho-stratigraphic traps in the continental slope.

Theoretical investigation of graphdiyne-supported single-cluster catalysts for electroreduction of nitric oxide

The electrochemical NO reduction reaction (NORR) to NH3 offers an efficient, environmentally friendly strategy for NO removal and NH3 production, but developing effective catalysts to facilitate the conversion of NO into NH3 remains a challenge. Single-cluster catalysts (SCCs) with multi-metallic sites show promise due to the synergistic interactions among the active atoms. Herein, utilizing density functional theory (DFT) and grand-canonical DFT (GC-DFT), we systematically investigated the potential of late transition metal (TM = Fe, Co, Ni, Cu, Ru, Rh, Pd, Pt) clusters on graphdiyne (TMx/GDY, x = 1–5) for NORR. Ni3/GDY, Pd3/GDY, and Pt3/GDY emerged as the most promising candidates, demonstrating stability, excellent NORR activity, and HER suppression. Their outstanding performance is attributed to the moderate adsorption of NO, with the dxz/dyz orbitals playing a key role in NO activation. GC-DFT results highlight nonlinear variation of intermediate grand free energies with the applied potential. Detailed electronic property analyses were conducted to reveal the charge effects induced by the applied chemical potential. This study provides valuable insights into SCC-catalyzed NO reduction and highlights the significance of potential effects in theoretical simulations of electrochemical systems.

Data-Driven Design of Single-Atom Electrocatalysts with Intrinsic Descriptors for Carbon Dioxide Reduction Reaction

The strategic manipulation of the interaction between a central metal atom and its coordinating environment in single-atom catalysts (SACs) is crucial for catalyzing the CO2 reduction reaction (CO2RR). However, it remains a major challenge. While density-functional theory calculations serve as a powerful tool for catalyst screening, their time-consuming nature poses limitations. This paper presents a machine learning (ML) model based on easily accessible intrinsic descriptors to enable rapid, cost-effective, and high-throughput screening of efficient SACs in complex systems. Our ML model comprehensively captures the influences of interactions between 3 and 5d metal centers and 8 C, N-based coordination environments on CO2RR activity and selectivity. We reveal the electronic origin of the different activity trends observed in early and late transition metals during coordination with N atoms. The extreme gradient boosting regression model shows optimal performance in predicting binding energy and limiting potential for both HCOOH and CO production. We confirm that the product of the electronegativity and the valence electron number of metals, the radius of metals, and the average electronegativity of neighboring coordination atoms are the critical intrinsic factors determining CO2RR activity. Our developed ML models successfully predict several high-performance SACs beyond the existing database, demonstrating their potential applicability to other systems. This work provides insights into the low-cost and rational design of high-performance SACs.

Aldehyde End-Capped Degradable Polyethylenes From Hydrogen-Controlled Ethylene/CO Copolymerization.

To access degradable polyolefin plastic, non-alternating copolymerization of ethylene (E) and carbon monoxide (CO) for producing polyethylene (PE) with in-chain ketones is particularly appealing; however, it still presents significant challenges such as molecular weight modulation (hydrogen response) and chain endgroup control (functional terminal). In this study, we achieved hydrogen-controlled E/CO non-alternating copolymerization using late transition metal catalysts. This process results in linear PEs containing the desired non-alternating in-chain keto groups (1.0-9.3 mol %) and with tunable molecular weights ranging from 43 to 195 kDa. In this reaction, H2 serves as a chain transfer agent, modulating the polymer's molecular weight, forming unique aldehyde endgroups and eliminating usual olefinic endgroups; CO undergoes non-alternating insertion into the PE chain, resulting in a strictly non-alternating structure (>99 %) for the keto-PE. The dispersed incorporation of in-chain keto groups retains bulk properties of PE and makes PE susceptible to photodegradation, which produces significantly lower molecular weight polymers and oligomers with unambiguous vinyl and acetyl terminals.

Aldehyde End‐Capped Degradable Polyethylenes From Hydrogen‐Controlled Ethylene/CO Copolymerization

AbstractTo access degradable polyolefin plastic, non‐alternating copolymerization of ethylene (E) and carbon monoxide (CO) for producing polyethylene (PE) with in‐chain ketones is particularly appealing; however, it still presents significant challenges such as molecular weight modulation (hydrogen response) and chain endgroup control (functional terminal). In this study, we achieved hydrogen‐controlled E/CO non‐alternating copolymerization using late transition metal catalysts. This process results in linear PEs containing the desired non‐alternating in‐chain keto groups (1.0–9.3 mol %) and with tunable molecular weights ranging from 43 to 195 kDa. In this reaction, H2 serves as a chain transfer agent, modulating the polymer's molecular weight, forming unique aldehyde endgroups and eliminating usual olefinic endgroups; CO undergoes non‐alternating insertion into the PE chain, resulting in a strictly non‐alternating structure (>99 %) for the keto‐PE. The dispersed incorporation of in‐chain keto groups retains bulk properties of PE and makes PE susceptible to photodegradation, which produces significantly lower molecular weight polymers and oligomers with unambiguous vinyl and acetyl terminals.

Menopausal stage transitions and their associations with overall and individual sleep quality in middle-aged Korean women

BackgroundUnderstanding the association between the menopausal transition and declining sleep quality can guide optimal timing for preventive interventions in transitioning women. However, studies lack representation of Asian women and sufficient data on the progression of menopausal stages and sleep quality changes over time in this population. MethodsThis study included 3305 women in the pre-menopause stage at baseline. The sleep quality and its components were assessed using the Pittsburgh Sleep Quality Index (PSQI). Menopausal stages were classified as pre-menopause, early transition, late transition, and post-menopause according to the Stages of Reproductive Aging Workshop+10 (STRAW+10) criteria. We estimated the longitudinal association between menopausal stage changes over time and the PSQI score, and examined the effect of being overweight. ResultsThe trends in the PSQI scores and its components according to the menopausal stage changes over time showed that with the exception of sleep duration and habitual sleep efficiency, an overall decline was noted in sleep health during late transition and post-menopause compared to pre-menopause. These associations were independent of time-variant annual chronological aging, which was not significantly associated with sleep deterioration. Additionally, although the associations between menopausal stages and sleep quality did not significantly differ by adiposity level, the overweight group exhibited worse PSQI scores and components than did the non-overweight group. LimitationSleep quality and menopausal stage were assessed using self-reported questionnaires without objective measures. ConclusionOur study underscores the importance of screening for sleep quality deterioration and implementing appropriate measures for women experiencing menopausal transition.