Browse Articles

MR perfusion source mapping depicts venous territories and reveals perfusion modulation during neural activation

Abstract The cerebral venous system plays a crucial role in neurological and vascular conditions, yet its hemodynamics remain underexplored due to its complexity and variability across individuals. To address this, we develop a venous perfusion source mapping method using Displacement Spectrum MRI, a non-contrast technique that leverages blood water as an endogenous tracer. Our technique encodes spatial information into the magnetization of blood water spins during tagging and detects it once the tagged blood reaches the brain’s surface, where the signal-to-noise ratio is 3–4 times higher. We resolve the sources of blood entering the imaging slice across short (10 ms) to long (3 s) evolution times, effectively capturing perfusion sources in reverse. This approach enables the measurement of slow venous blood flow, including potential contributions from capillary beds and surrounding tissue. We demonstrate perfusion source mapping in the superior cerebral veins, verify its sensitivity to global perfusion modulation induced by caffeine, and establish its specificity by showing repeatable local perfusion modulation during neural activation. From all blood within the imaging slice, our method localizes the portion originating from an activated region upstream.

Performance of Dialysis Facilities after Health-Equity Scoring Incentive

Structural basis for saxitoxin congener binding and neutralization by anuran saxiphilins

Abstract Dinoflagellates and cyanobacteria produce saxitoxin (STX) and ~50 congeners that disrupt bioelectrical signals by blocking voltage-gated sodium channels (Na V s). Consuming seafood carrying these toxins causes paralytic shellfish poisoning (PSP). Although Na V s and anuran STX binding proteins (saxiphilins, Sxphs) use convergent STX binding modes, the structural basis for STX congener recognition is unknown. Here, we show that American bullfrog ( Rana catesbeiana ) Rc Sxph and High Himalaya frog ( Nanorana parkeri ) Np Sxph sequester STX congeners using a ‘lock and key’ mode shared with STX. Importantly, functional studies demonstrate that Sxph ‘toxin sponges’ reverse Na V block by multiple STX congeners and detect these toxins in a radioligand binding assay (RBA) used for environmental testing. Together, our study establishes how Sxphs sequester select neurotoxins and uncover STX congener-specific interactions distinct from Na V s. These findings expand understanding of toxin sponge action and provide a foundation for strategies to monitor and mitigate the harmful effects of STX congeners.

Tirzepatide for Heart Failure and Obesity

Giant electrocaloric effect in high-polar-entropy perovskite oxides

Hierarchical motion perception as causal inference

Abstract Motion can only be defined relative to a reference frame; yet it remains unclear which reference frame guides perception. A century of psychophysical studies has produced conflicting evidence: retinotopic, egocentric, world-centric, or even object-centric. We introduce a hierarchical Bayesian model mapping retinal velocities to perceived velocities. Our model mirrors the structure in the world, in which visual elements move within causally connected reference frames. Friction renders velocities in these reference frames mostly stationary, formalized by an additional delta component (at zero) in the prior. Inverting this model automatically segments visual inputs into groups, groups into supergroups, progressively inferring structured reference frames and “perceives" motion in the appropriate reference frame. Critical model predictions are supported by two experiments, and fitting our model to the data allows us to infer the subjective set of reference frames used by individual observers. Our model provides a quantitative normative justification for key Gestalt principles providing inspiration for building better models of visual processing in general.

Defanging the Neutrophil to Treat Bronchiectasis

How Trump’s attack on universities is putting research in peril

Multi-ancestry sequencing-based genome-wide association study of C-reactive protein in 513,273 genomes

Pavement Burns

Neutrophil single-cell analysis identifies a type II interferon-related subset for predicting relapse of autoimmune small vessel vasculitis

Southern Tick-Associated Rash Illness

Author Correction: Quantifying both socioeconomic and climate uncertainty in coupled human–Earth systems analysis

Oral Anticoagulation during TAVI

How Democrats and Republicans cite science: study reveals stark differences

Ultra-weak infrared light detection based on steep-slope phototransistors

Cutaneous Leishmaniasis

A CRISPR homing screen finds a chloroquine resistance transporter-like protein of the Plasmodium oocyst essential for mosquito transmission of malaria

Abstract Genetic screens with barcoded PlasmoGEM vectors have identified thousands of Plasmodium berghei gene functions in haploid blood stages, gametocytes and liver stages. However, the formation of diploid cells by fertilisation has hindered similar research on the parasites’ mosquito stages. In this study, we develop a scalable genetic system that uses barcoded gene targeting vectors equipped with a CRISPR-mediated homing mechanism to generate homozygous loss-of-function mutants after one parent introduces a modified allele into the zygote. To achieve this, we use vectors additionally expressing a target gene specific gRNA. When integrated into one of the parental alleles it directs Cas9 to the intact allele after fertilisation, leading to its disruption. This homing strategy is 90% effective at generating homozygous gene editing of a fluorescence-tagged reporter locus in the oocyst. A pilot screen identifies PBANKA_0916000 as a chloroquine resistance transporter-like protein (CRTL) essential for oocyst growth and sporogony, pointing to an unexpected importance for malaria transmission of the poorly understood digestive vacuole of the oocyst that contains hemozoin granules. Homing screens provide a method for the systematic discovery of malaria transmission genes whose first essential functions are after fertilisation in the bloodmeal, enabling their potential as targets for transmission-blocking interventions to be assessed.

Long-Term Effects of Atidarsagene Autotemcel for Metachromatic Leukodystrophy

Baffling chronic pain eases after doses of gut microbes