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Ultrasmall superparamagnetic iron oxide nanoparticles (usSPIONs) are promising alternatives to gadolinium‐based contrast agents for positive contrast enhancement in magnetic resonance imaging (MRI). Unlike larger SPIONs that primarily function as T2/T2* negative contrast agents, usSPIONs with core diameters below 5 nm can effectively shorten T1 relaxation times, producing bright signals in T1‐weighted images. This distinct behavior stems from their unique magnetic properties, including single‐domain configurations, surface spin canting, and rapid Néel relaxation dynamics, which are particularly enhanced at low magnetic field strengths. The biocompatibility of iron oxide, efficient renal clearance pathways, and versatility for surface functionalization offer potential advantages over gadolinium‐based agents, especially regarding safety concerns related to nephrogenic systemic fibrosis and gadolinium deposition. These nanoparticles show particular promise for applications in low‐field MRI, vascular imaging, targeted molecular imaging, and theranostic platforms. Although challenges remain in optimizing synthesis methods for consistent production of monodisperse usSPIONs with tailored surface chemistry, ongoing research continues to advance their potential for clinical translation. This review explores the mechanisms, synthesis approaches, applications, and future perspectives of usSPIONs as positive contrast agents in MRI. Ultrasmall superparamagnetic iron oxide nanoparticles emerge as promising positive contrast agents for low‐field MRI. Unlike larger SPIONs, these particles exhibit enhanced T1 relaxivity through rapid magnetic fluctuations and surface spin canting. Their biocompatibility, renal clearance pathway, and bright contrast generation offer safer alternatives to gadolinium‐based agents, opening new possibilities for targeted imaging, angiography, and point‐of‐care diagnostics. Based on our discussion in the manuscript and current understanding of size‐dependent magnetic properties, we propose the following standardized nomenclature recommendations: (1) “paramagnetic‐like usSPIONs” for particles < 5 nm exhibiting predominantly T1 contrast effects with minimal superparamagnetic behavior; (2) “surface‐modified superparamagnetic nanoparticles” for particles 5–10 nm where surface effects significantly alter classical superparamagnetic behavior; and (3) “classical superparamagnetic iron oxide nanoparticles” for particles > 10 nm exhibiting traditional superparamagnetic behavior with dominant T2/T2* effects.

Amphetamines (AMPHs) are psychostimulants commonly used for the treatment of neuropsychiatric disorders. They are also misused (AMPH use disorder; AUD), with devastating outcomes. Recent studies have implicated dysbiosis in the pathogenesis of AUD. However, the mechanistic roles of microbes in AUD are unknown. ( ) is a bacterium that increases in abundance in both rats and humans upon AMPH exposure. releases short-chain fatty acids (SCFAs), bacterial byproducts thought to play a fundamental role in the gut-brain axis as well as the pathogenesis of AUD. We demonstrate that in gnotobiotic colonization with or dietary supplementation of the SCFA butyrate, a potent inhibitor of histone deacetylases (HDACs), enhances the psychomotor and rewarding properties of AMPH as well as its ability to promote male sexual motivation. Furthermore, solely HDAC1 RNAi targeted inhibition recapitulates these enhancements, pointing to a specific process underlying this phenomenon. Of note is that the expression of these AMPH behaviors is determined by the increase in extracellular dopamine (DA) levels that result from AMPH-induced reversal of DA transporter (DAT) function, termed non-vesicular DA release (NVDR). The magnitude of AMPH-induced NVDR is dictated, at least in part, by DAT expression levels. Consistent with our behavioral data, we show that , butyrate, and HDAC1 inhibition enhance NVDR by elevating DAT expression. Thus, the participation of in AUD stems from its ability to release butyrate and inhibit HDAC1. These data offer a microbial target and probiotic interventions for AUD treatment.

Abstract Rationale Several extrapulmonary disorders have been linked to cigarette smoking. Smoking is reported to cause cystic fibrosis transmembrane conductance regulator (CFTR) dysfunction in the airway, and is also associated with pancreatitis, male infertility, and cachexia, features characteristic of cystic fibrosis and suggestive of an etiological role for CFTR. Objectives To study the effect of cigarette smoke on extrapulmonary CFTR function. Methods Demographics, spirometry, exercise tolerance, symptom questionnaires, CFTR genetics, and sweat chloride analysis were obtained in smokers with and without chronic obstructive pulmonary disease (COPD). CFTR activity was measured by nasal potential difference in mice and by Ussing chamber electrophysiology in vitro. Serum acrolein levels were estimated with mass spectroscopy. Measurements and Main Results Healthy smokers (29.45 ± 13.90 mEq), smokers with COPD (31.89 ± 13.9 mEq), and former smokers with COPD (25.07 ± 10.92 mEq) had elevated sweat chloride levels compared with normal control subjects (14.5 ± 7.77 mEq), indicating reduced CFTR activity in a nonrespiratory organ. Intestinal current measurements also demonstrated a 65% decrease in CFTR function in smokers compared with never smokers. CFTR activity was decreased by 68% in normal human bronchial epithelial cells exposed to plasma from smokers, suggesting that one or more circulating agents could confer CFTR dysfunction. Cigarette smoke–exposed mice had decreased CFTR activity in intestinal epithelium (84.3 and 45%, after 5 and 17 wk, respectively). Acrolein, a component of cigarette smoke, was higher in smokers, blocked CFTR by inhibiting channel gating, and was attenuated by antioxidant N-acetylcysteine, a known scavenger of acrolein. Conclusions Smoking causes systemic CFTR dysfunction. Acrolein present in cigarette smoke mediates CFTR defects in extrapulmonary tissues in smokers.

The scientific community has expressed interest in the potential of phased array radars (PARs) to observe the atmosphere with finer spatial and temporal scales. Although convergence has occurred between the meteorological and engineering communities, the need exists to increase access of PAR to meteorologists. Here, we facilitate these interdisciplinary efforts in the field of ground-based PARs for atmospheric studies. We cover high-level technical concepts and terminology for PARs as applied to studies of the atmosphere. A historical perspective is provided as context along with an overview of PAR system architectures, technical challenges, and opportunities. Envisioned scan strategies are summarized because they are distinct from traditional mechanically scanned radars and are the most advantageous for high-resolution studies of the atmosphere. Open access to PAR data is emphasized as a mechanism to educate the future generation of atmospheric scientists. Finally, a vision for the future of operational networks, research facilities, and expansion into complementary radar wavelengths is provided.

Index funds are an increasingly important part of the U.S. stock market, with the average S&P 1500 firm having more than 20% of its equity held by index funds in 2018. Compared to other owners, index fund managers face greater constraints and limitations when selecting portfolio investments and making trading decisions about whether, and when, to enter or exit a position. Using hand-collected data to examine the ramifications of increased ownership by constrained index funds, we find that greater index fund ownership is associated with less bias (greater frequency of missing earnings and fewer abnormal accruals) and less obfuscation (more readable, more negative, and more specific disclosures) in financial reporting. Additional analysis finds results consistent with this effect being due to index funds wielding power through lower trading and not higher oversight. Finally, we document several important conceptual and empirical factors to consider when examining index fund ownership, compared to institutional-level holdings or changes in index constituents.

Natural history museums are vital repositories of specimens, samples and data that inform about the natural world; this Formal Comment revisits a Perspective that advocated for the adoption of compassionate collection practices, querying whether it will ever be possible to completely do away with whole animal specimen collection.

Since their discovery, many studies have been conducted to understand the effect of X-rays on the neural function and behavior of animals. These studies have examined a broad range of acute and chronic effects and a subset of studies has attempted to determine if X-rays can produce any sensory responses. Here we review literature from the discovery of X-rays in 1895 until the present to better understand the chronology of studies of acute X-ray behavioral effects in animals and to assess the evidence for the detection of X-rays by sensory receptors in animals. We focus on the changes in appetitive and consummatory behavior, radiotaxis, behavioral arousal, and olfactory responses to X-rays that have been reported in the literature. Taken together, the reviewed literature provides a large body of evidence that X-rays can induce sensory responses in a wide variety of animals and also suggests that at least some of these responses are mediated by sensory receptors.

Chronic wounds are a burden to millions of patients worldwide and impaired wound closure has been shown to be associated with wound microbiota. Recent evidence suggests human genetics may shape differences in composition of wound microbiomes. Here, a microbiome genome-wide association study was used to test effects of human genetics on the relative abundances of bacterial species in chronic wounds. Sixteen species were associated with 193 genetic loci distributed across 25 non-overlapping genomic regions, with per-species heritability estimates ranging up to 20%. Functional analyses on genomic regions and species resulted in overrepresentation of pathways relevant to microbial infection and wound healing. Species associated with host genetics exhibited co-occurrence relationships with common wound pathogens including Staphylococcus aureus . Moreover, the genetic distance among patients was significantly related to differences in their overall wound microbiome composition. Identification of genetic biomarkers reveals predictive risk factors and new mechanistic insight for chronic wounds.

UN Sustainable Development Goal (SDG) 2: Zero Hunger links ending hunger to achieving food security, improving nutrition, and promoting sustainable agriculture. The Pacific Island Countries and Territories (PICTs) is a region where such linkages can be investigated as the PICTs are confronting climate change while facing a decrease in available arable land and increasing rates of urbanisation. Around 80% of all Pacific Islanders still rely on agricultural produce from their own gardens or from small holder farmers to support or to supplement their diets. The Food and Agriculture Organisation (FAO) has declared the years 2019–2028 to be the Decade of Family Farming. Food imports are increasingly common in PICTs, and can provide cheap, although not particularly nutritious foods, leading to generalised health problems. Increased reliance on imports is itself an indicator of diminishing food security, and with the PICTs facing a range of food security challenges, it is timely to assess the existing literature in the PICTs on the relationship between smallholder farming and food security. This scoping review analyses 49 peer reviewed and grey literature studies in English from 1970–2019 concerning the relationship between food security and small holder farming in the PICTs. It identifies four main themes: (1) Community adaptation, resilience and crop diversification; (2) Decreased availability of local foods and land; (3) Changes in diet; (4) Gender and agricultural production. The review shows Pacific peoples quickly adapt to changing circumstances to plant different crops both for food and for sale, and it identifies the role of small holder agriculture as crucial to: (1) growing local foods to support food security, and (2) expanding domestic asset creation to promote economic development, especially for women.

In July 2018, unmanned aerial systems (UASs) were deployed to measure the properties of the lower atmosphere within the San Luis Valley, an elevated valley in Colorado, USA, as part of the Lower Atmospheric Profiling Studies at Elevation – a Remotely-piloted Aircraft Team Experiment (LAPSE-RATE). Measurement objectives included detailing boundary layer transition, canyon cold-air drainage and convection initiation within the valley. Details of the contribution to LAPSE-RATE made by the University of Kentucky are provided here, which include measurements by seven different fixed-wing and rotorcraft UASs totaling over 178 flights with validated data. The data from these coordinated UAS flights consist of thermodynamic and kinematic variables (air temperature, humidity, pressure, wind speed and direction) and include vertical profiles up to 900 m above the ground level and horizontal transects up to 1500 m in length. These measurements have been quality controlled and are openly available in the Zenodo LAPSE-RATE community data repository (https://zenodo.org/communities/lapse-rate/, last access: 23 July 2020), with the University of Kentucky data available at https://doi.org/10.5281/zenodo.3701845 (Bailey et al., 2020).