Targeted Use of Computed Tomographic Coronary Angiography in Acute Chest Pain.

August 29, 2026| Source: The New England journal of medicine

Many patients with suspected acute coronary syndrome in whom myocardial infarction has been ruled out in the emergency department remain at risk for cardiovascular events. Whether further investigation reduces this risk is unknown. In a multicenter, randomized, controlled trial, patients who presented to an emergency department in 14 hospitals across the United Kingdom were enrolled if myocardial infarction had been ruled out and high-sensitivity cardiac troponin testing indicated an intermediate risk of a cardiovascular event (maximum high-sensitivity cardiac troponin I or T concentration, >5 ng per liter). Participants were randomly assigned in a 1:1 ratio to receive either outpatient computed tomographic (CT) coronary angiography-guided care or standard care. The primary outcome was a composite of myocardial infarction or death from a cardiac cause. From September 18, 2019, to May 11, 2023, a total of 3170 participants (median age, 61 years; female sex, 30.2%) were assigned to undergo CT coronary angiography (1587 participants) or receive standard care (1583 participants). At 90 days after randomization, CT coronary angiography had been performed in 1462 participants (92.1%) in the CT coronary angiography group and in 35 participants (2.2%) in the standard-care group. Overall, 7 participants (0.4%) had a CT coronary angiography-related adverse event. After a median of 3.0 years, at which point the number of primary-outcome events in the standard-care group exceeded the prespecified minimum of 97, a primary-outcome event had occurred in 112 participants (7.1%) in the CT coronary angiography group and in 116 (7.3%) in the standard-care group (adjusted hazard ratio, 0.95; 95% confidence interval, 0.73 to 1.23; P = 0.71). In patients with suspected acute coronary syndrome in whom myocardial infarction had been ruled out, routine CT coronary angiography-guided management did not result in a lower incidence of subsequent myocardial infarction or death from a cardiac cause than standard care. (Funded by the British Heart Foundation; TARGET-CTCA ClinicalTrials.gov number, NCT03952351.).

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Extensive glacier loss in the coterminous United States.

Glaciers populate the mountain ranges of the western conterminous United States and despite their importance to alpine hydrology, their area and volume change have never been comprehensively evaluated. Our study shows that since the mid-twentieth century about one-quarter of the glaciers have disappeared and the overall area and volume are reduced by one-third. The pattern of glacier shrinkage suggests most glaciers in the conterminous United States are largely maintained by local topographic in

Physical/TechOctober 20, 2026

Reaction-based cryo-EM resolves the continuous conformational spectrum of CTP synthase catalysis.

Capturing enzymes under native turnover conditions remains a grand challenge in structural biology. Here, we develop a reaction-based cryo-electron microscopy (cryo-EM) strategy that directly samples Drosophila melanogaster cytidine triphosphate synthase (CTPS) from actively catalyzing mixtures containing only natural substrates and allosteric effectors. By integrating reaction-based sampling with three-dimensional variability analysis, we resolve a continuous conformational spectrum of CTPS dur

Physical/TechOctober 20, 2026

GTP orchestrates CTP synthase via an allosteric effector-cycling mechanism.

Cytidine triphosphate (CTP), a fundamental building block of RNA, plays vital roles in diverse biological processes. CTP synthase (CTPS) is the only known enzyme for de novo synthesis of CTP. Efficient CTPS catalysis requires guanosine triphosphate (GTP) in a dose-dependent, nonconsumptive manner; however, the precise mechanism by which GTP drives CTP formation remains unclear. Here, we integrate a series of cryo-EM structures of Drosophila melanogaster CTPS captured from actively catalyzing sam

Physical/TechOctober 20, 2026

Antiferromagnetism and tightly bound Cooper pairs induced by kinetic frustration.

Antiferromagnetism and superconductivity are often viewed as competing orders in correlated electron systems. Here, we demonstrate that kinetic frustration in hole motion facilitates their coexistence within the square-lattice repulsive Hubbard model. Combining exact analytical solutions on tailored geometries with large-scale numerical simulations, we reveal a robust pairing mechanism: Holes on opposite sublattices behave as if they carry opposite effective charges due to spin singlet formation

Physical/TechOctober 20, 2026

Coordinated transformations of the labyrinth and occiput during the dinosaur-bird transition.

Evolutionary shape changes of the vertebrate semicircular canals (SCCs) are often ascribed to evolutionary transitions in locomotion, including the origin of flight during the dinosaur-bird transition. However, the potential for transformations of braincase architecture to influence SCC shape independent of sensory-functional adaptation has generally been overlooked. We evaluate the influence of both factors using a large dataset of 146 living and recently extinct crown birds, including taxa rep