O Activation and Enzymatic C-H Bond Activation Mediated by a Dimanganese Cofactor.

Dioxygen (O) is a potent oxidant used by aerobic organisms for energy transduction and critical biosynthetic processes. Numerous metalloenzymes harness O to mediate C-H bond hydroxylation reactions, but most commonly feature iron or copper ions in their active site cofactors. In contrast, many manganese-activated enzymes─such as glutamine synthetase and isocitrate lyase─perform redox neutral chemical transformations and very few are known to activate O or C-H bonds.

Univariate Prediction of Hammett Parameters and Select Relative Reaction Rates Using Loewdin Atomic Charges.

Loewdin charges from density functional theory calculations were used here to obtain general, univariate linear correlations for the prediction of experimental Hammett parameters and relative reaction rates. While previous studies have established that Hirshfeld and CM5 charges perform strongly as univariate predictors, the near-ubiquitous Loewdin charges have not yet been evaluated. To this end, we assess the predictive capability of Loewdin charges for three chemical systems.

C-H Bond Activation by Sulfated Zirconium Oxide is Mediated by a Sulfur-Centered Lewis Superacid.

Sulfated zirconium oxide (SZO) catalyzes the hydrogenolysis of isotactic polypropylene (iPP, Mn = 13.3 kDa, Đ = 2.4, = 94 %) or high-density polyethylene (HDPE, Mn = 2.

Human AI collaboration for unsupervised categorization of live surgical feedback.

Formative verbal feedback during live surgery is essential for adjusting trainee behavior and accelerating skill acquisition. Despite its importance, understanding optimal feedback is challenging due to the difficulty of capturing and categorizing feedback at scale. We propose a Human-AI Collaborative Refinement Process that uses unsupervised machine learning (Topic Modeling) with human refinement to discover feedback categories from surgical transcripts.

Changes in DNA methylation are associated with systemic lupus erythematosus flare remission and clinical subtypes.

Background: Systemic lupus erythematosus (SLE) has numerous symptoms across organs and an unpredictable flare-remittance pattern. This has made it challenging to understand drivers of long-term SLE outcomes. Our objective was to identify whether changes in DNA methylation over time, in an actively flaring SLE cohort, were associated with remission and whether these changes meaningfully subtype SLE patients.

Palovarotene (Sohonos), a synthetic retinoid for reducing new heterotopic ossification in fibrodysplasia ossificans progressiva: history, present, and future.

Retinoids are metabolic derivatives of vitamin A and play crucial roles in the regulation of various tissues and organs during prenatal and postnatal development. Active retinoids, like all-trans-retinoic acid, are synthesized in the cytoplasm and subsequently interact with nuclear retinoic acid receptors (RARα, RARβ, and RARγ) to enhance transcription of specific genes. In the absence of retinoids, RARs can still bind to response elements of target genes but repress their transcription.

Mesoscale functional architecture in medial posterior parietal cortex.

The posterior parietal cortex () in mice has various functions including multisensory integration, vision-guided behaviors, working memory, and posture control. However, an integrated understanding of these functions and their cortical localizations in and around the PPC and higher visual areas (), has not been completely elucidated. Here we simultaneously imaged the activity of thousands of neurons within a 3 × 3 mm field-of-view, including eight cortical areas around the PPC, during behavior with a two-photon mesoscope.

Assembly of the Tricyclic Core of Alopecurone C by Asymmetric Donor/Donor Carbene C-H Insertion.

Two routes to assemble the complete tricyclic core of alopecurone C are described. In the first-generation route, an efficient synthesis of the "eastern" half of the target, including a decagram-scale rhodium-catalyzed C-H insertion reaction, was developed. When this route proved intractable for assembling the final flavanone ring, a successful second-generation route was developed from a flavanone precursor (naringenin) employing a later stage C-H insertion.

Evidence-based guideline: premature ovarian insufficiency.

Study Question: How should premature/primary ovarian insufficiency (POI) be diagnosed and managed based on the best available evidence from published literature?

Summary Answer: The current guideline provides 145 recommendations on symptoms, diagnosis, causation, sequelae, and treatment of POI.

What Is Known Already: Premature ovarian insufficiency (POI) presents a significant challenge to women's health, with far-reaching implications, both physically and emotionally. The potential implications include adverse effects on quality of life; fertility; and bone, cardiovascular, and cognitive health.

Clinical Use of Home OCT Data to Manage Neovascular Age-Related Macular Degeneration.

To investigate how home optical coherence tomography (OCT) influences the clinical decision-making of retina specialists for the management of neovascular age-related macular degeneration (nAMD). In this retrospective imaging review, 15 retina specialists each evaluated 10 home OCT data segments from 29 eyes being treated for nAMD. Based on OCT data, indications were identified for when eyes should be treated, which antivascular endothelial growth factor should be used, and the specific retinal fluid and time thresholds for notification.

Evidence-based guideline: Premature Ovarian Insufficiency.

Study Question: How should premature/primary ovarian insufficiency (POI) be diagnosed and managed, based on the best available evidence from published literature?

Summary Answer: The current guideline provides 145 recommendations on symptoms, diagnosis, causation, sequelae and treatment of POI.

What Is Known Already: Premature ovarian insufficiency (POI) presents a significant challenge to women's health, with far-reaching implications, both physically and emotionally. The potential implications include adverse effects on quality of life; fertility; and bone, cardiovascular and cognitive health.

Atomic-Scale Imaging of Polymers and Precision Molecular Weight Analysis.

Polymer design requires fine control over syntheses and a thorough understanding of their macromolecular structure. Herein, near-atomic level imaging of polymers is achieved, enabling the precise determination of one of the most important macromolecular characteristics: molecular weight. By judiciously designing and synthesizing different linear metal(loid)-rich homopolymers, subnanoscale polymer imaging is achieved through annular dark field-scanning transmission electron microscopy (ADF-STEM), owing to the incorporation of high atoms in the side chain of the monomeric units.

Twice-Yearly Lenacapavir for HIV Prevention in Men and Gender-Diverse Persons.

Background: Twice-yearly subcutaneous lenacapavir has been shown to be efficacious for prevention of HIV infection in cisgender women. The efficacy of lenacapavir for preexposure prophylaxis (PrEP) in cisgender men, transgender women, transgender men, and gender-nonbinary persons is unclear.

Methods: In this phase 3, double-blind, randomized, active-controlled trial, we randomly assigned participants in a 2:1 ratio to receive subcutaneous lenacapavir every 26 weeks or daily oral emtricitabine-tenofovir disoproxil fumarate (F/TDF).

Selective oxidation of active site aromatic residues in engineered Cu proteins.

Recent studies have revealed critical roles for the local environments surrounding metallocofactors, such as the newly identified Cu site in particulate methane monooxygenases (pMMOs) and the second sphere aromatic residues in lytic polysaccharide monooxygenases (LPMOs), implicated in the protection against oxidative damage. However, these features are subjects of continued debate. Our work utilizes biotin-streptavidin (Sav) technology to develop artificial metalloproteins (ArMs) that mimic the active sites of natural copper metalloenzymes.

C-H functionalization of camphor through emerging approaches.

Camphor and related monoterpenoid natural products have served as versatile "chiral pool" materials in organic chemistry for over half a century. Historically, many researchers have used a variety of transformations involving orchestrated rearrangements of the bornane skeleton to functionalize the camphor framework, expanding the utility of this chiral building block. Recent developments in C-H functionalization methodologies provide myriad opportunities to derivatize the camphor framework in a selective and predictable fashion.

Lipid nanoparticle-mediated mRNA delivery to CD34 cells in rhesus monkeys.

Transplantation of ex vivo engineered hematopoietic stem cells (HSCs) can lead to robust clinical responses but carries risks of adverse events from bone marrow mobilization, chemotherapy conditioning and other factors. HSCs have been modified in vivo using lipid nanoparticles (LNPs) decorated with targeting moieties, which increases manufacturing complexity. Here we screen 105 LNPs without targeting ligands for effective homing to the bone marrow in mouse.

State of Practice on Transcranial MR-Guided Focused Ultrasound: A Report from the ASNR Standards and Guidelines Committee and ACR Commission on Neuroradiology Workgroup.

Transcranial focused ultrasound (FUS) is a versatile, MR-guided, incisionless intervention with diagnostic and therapeutic applications for neurologic and psychiatric diseases. It is currently FDA-approved as a thermoablative treatment of essential tremor and Parkinson disease. However, other applications of FUS including BBB opening for diagnostic and therapeutic applications, sonodynamic therapy, histotripsy, and low-intensity focused ultrasound neuromodulation are all in clinical trials.

Nutrient control of growth and metabolism through mTORC1 regulation of mRNA splicing.

Cellular growth and organismal development are remarkably complex processes that require the nutrient-responsive kinase mechanistic target of rapamycin complex 1 (mTORC1). Anticipating that important mTORC1 functions remained to be identified, we employed genetic and bioinformatic screening in C. elegans to uncover mechanisms of mTORC1 action.

Molecular Dynamics of the Davies Ambimodal C-H Functionalization/Cope Rearrangement Reaction.

The mechanism of the dirhodium-catalyzed combined C-H functionalization/Cope rearrangement (CH/Cope) reaction discovered by the Davies group has been investigated with density functional theory (DFT) calculations and quasi-classical molecular dynamics (MD) simulations. Computations from the Davies group previously showed that there is a post-transition state bifurcation leading to a direct CH reaction and also to the CH/Cope product. While this work was in preparation, the Tantillo group and the Ess group independently reported quantum mechanical and molecular dynamics studies on the dirhodium-tetracarboxylate-catalyzed diazoester CH/Cope and CH insertion reactions with 1,3-cyclohexadiene and 1,4-cyclohexadiene, respectively.

EXCELLENT Registry: A Prospective, Multicenter, Global Registry of Endovascular Stroke Treatment With the EMBOTRAP Device.

Background: The EXCELLENT registry aimed to evaluate the effectiveness of the EMBOTRAP Revascularization Device in an all-comer population in a real-world setting, with a focus on the composition of retrieved clots.

Methods: EXCELLENT is a prospective, global registry of patients with acute ischemic stroke treated with EMBOTRAP as the first-line mechanical thrombectomy device conducted at 34 sites (25 sites contributing clot) from September 2018 to March 2021, utilizing core imaging and central histology laboratories blinded to clinical data, independent 90-day modified Rankin Scale assessment and Clinical Events Committee.

Results: After screening 3799 patients, a total of 997 subjects (mean age, 70.

Central role of the ER proteostasis network in healthy aging.

Aging trajectories vary among individuals, characterized by progressive functional decline, often leading to disease states. One of the central hallmarks of aging is the deterioration of proteostasis, where the function of the endoplasmic reticulum (ER) is dramatically affected. ER stress is monitored and adjusted by the unfolded protein response (UPR); a signaling pathway that mediates adaptive processes to restore proteostasis.

An Air-Stable, Single-Component Iridium Precatalyst for the Borylation of C-H Bonds on Large to Miniaturized Scales.

The functionalization of C-H bonds enables the modification of complex molecules, often with the intention of forming compound libraries. The borylation of aryl C-H bonds is a widely used class of C-H bond functionalization, and conventional catalyst systems for the borylation of C-H bonds consist of an iridium source and an ,-ligand, in conjunction with pinacolborane, to form the active iridium(III) tris(boryl) catalyst. These multicomponent catalyst systems complicate borylation reactions at large and small scales, due to the air sensitivity of the most common iridium precursor [Ir(cod)OMe], and, particularly on small scale, the challenges associated with dispensing multiple components with differing solubilities or that are air-sensitive.