Iron speciation is one of the most widely applied proxies used to reconstruct oxygen levels and redox conditions in past aqueous environments. The iron speciation proxy estimates proportions of ...different reactive iron species in fine‐grained sedimentary rocks, which are mapped to redox conditions based on empirical calibrations from modern sediments. It is based on a standardized extraction technique of sequentially applying acetate, hydroxlamine‐HCl, dithionite, and oxalate solutions to a powdered sample in order to dissolve iron phases and quantify the amount of iron carried by carbonates, “easily reducible” oxyhydroxides, ferric iron (oxyhydr)oxides, and magnetite, respectively. Although tested on pure minerals and mixtures, assessments of whether this sequential extraction process accurately dissolves the targeted minerals in natural sediments and sedimentary rocks are lacking. In our study, residues from each sequential extraction step were analyzed using rock magnetic and X‐ray diffraction experiments to identify and quantify the iron‐bearing minerals that were dissolved. The dithionite extraction robustly removes the targeted mineralogy as magnetic data show it to solubilize nearly all of the goethite. However, magnetic quantification of magnetite was orders of magnitude less than the iron measured in the oxalate extraction; X‐ray diffraction data suggest that dissolution of iron‐bearing clays, specifically berthierine/chamosite, could explain this disparity. Our data compilation shows higher values of iron from the oxalate extraction in Precambrian sedimentary rock samples, suggesting a significant temporal shift in iron cycling. Recognition of heterogeneity in chemical extraction efficiency and targeting is vital for holistic multiproxy interpretation of past oxygen levels and communication between disciplines.
Plain Language Summary
Sequential chemical extractions, where a series of solutions are applied to a powdered rock sample to selectively dissolve certain phases, are heavily utilized throughout Earth Science research. These methodologies provide a tool for estimating different reactive forms of an element; understanding how these pools change over time in a given environment allows us to better understand cycling of the element by biological, chemical, and geologic processes on the Earth's surface. In this study, we focus on a sequential chemical extraction method that measures the element iron, the most abundant transition metal in Earth's crust. Although heavily utilized for understanding nutrient cycling and ancient oxygen levels, the method is largely untested using actual rock samples that contain a mixture of minerals of different shapes and sizes. Such tests are needed to evaluate whether the extractions are accurately and completely dissolving the targeted minerals. We utilized magnetic and X‐ray diffraction methods that can sensitively measure iron minerals within natural samples. We found that some of the extractions worked as expected, but others did not, dissolving additional unexpected mineral types and/or slowly dissolving minerals across multiple extractions.
Key Points
Magnetic and X‐ray diffraction analyses on natural samples corroborate the efficiency of certain chemical extractions, such as dithionite
The majority of iron in the oxalate extraction is not dissolved from magnetite, but instead comes from iron‐bearing clays
Recognition of the heterogeneity in chemical extraction efficiency and targeting is vital for studies of past and present iron cycling
Abstract Background SPECT/CT integrates functional nuclear medicine imaging with anatomic CT characteristics. Aortic diameter provides important information when increased, indicating patients at ...higher risk of aortic dissection or rupture, and is routinely evaluated on CT scans but rarely on CT attenuation correction (CTAC) maps from SPECT/CT. Purpose We aimed to develop a deep learning (DL) method for fully automatic aortic diameter measurements on CTAC in patients undergoing SPECT/CT myocardial perfusion imaging (MPI). Methods Figure 1 shows the study design. We included CTAC from patients undergoing SPECT/CT MPI from 2 sites participating in the REFINE SPECT registry. An open-source multi-structure CT segmentation was used to segment the aorta, pulmonary artery (PA), and 3 thoracic vertebrae (Th4-Th6). The diameter of the ascending (Asc) and descending (Desc) aorta was measured automatically at each slice (on average 7 slices) at the level of the PA bifurcation (Th4-Th6). The median value of all obtained measurements of the diameter of the Asc and Desc aorta was used in further analysis. The abnormal diameter of the Asc aorta was defined as an aortic diameter >40 mm whereas the abnormal diameter of the Desc aorta >30 mm. Abnormal myocardial perfusion was defined as total perfusion deficit (TPD) >5%. Results In total 4,589 patients were included, of whom 2,596 (56.6%) were male, and the median age was 66.0 (interquartile range IQR 57.0-74.0). During the median 3.6 years (2.0-5.0) follow-up, 352 (7.7%) patients died. The median Asc aorta diameter was 36.4 mm (33.6-39.4), whereas the median Desc aorta diameter was 30.8 mm (28.6-33.3). Patients with abnormal Asc and Desc aortic diameter were at higher risk of death compared to subjects with normal aortic diameter (Asc aorta - unadjusted hazard ratio HR 1.37, 95% CI 1.08-1.74, p=0.01; Desc aorta – unadjusted HR 1.9, 95% CI 1.51-2.40, p<0.001) (Figure 2). Abnormal TPD was present in 2,302 (50.2%) patients. Patients with normal TPD and abnormal Asc aortic diameter were at higher risk of death compared to patients with normal TPD and normal Asc aorta diameter (unadjusted HR 1.26, 95% CI 0.83-1.90, p=0.27). Subjects with normal TPD and abnormal Desc aorta diameter had an elevated risk of death compared to patients with abnormal TPD and normal Desc aorta diameter (unadjusted HR 2.10, 95% CI 1.43-3.08, p<0.001). Patients with abnormal TPD and abnormal Asc aortic diameter were at higher risk of death compared to patients with abnormal TPD and normal Asc aorta diameter (unadjusted HR 1.35, 95% CI 1.00-1.81, p=0.04). Moreover, subjects with abnormal TPD and abnormal Desc aorta diameter had an elevated risk of death compared to patients with abnormal TPD and normal Desc aorta diameter (unadjusted HR 1.57, 95% CI 1.18-2.10, p<0.001). Conclusion DL-based aortic diameter measurements on CTAC in patients undergoing SPECT/CT MPI can help identify patients at higher risk of death due to abnormal aortic diameter.
Change of direction speed (CODS) is often considered a main determinant of successful performance in many team sports and is routinely measured using field‐based tests. However, controversy regarding ...test selection still exists based upon the reliability and specificity of the tests. The purpose of this study was to determine and compare the reliability, factorial validity, and interrelationships of five frequently used CODS tests (Illinois, L‐Run, Pro‐Agility, T‐test, and 505). Forty‐four physical education students (male n = 24; female n = 20; age; 16.7 ± 0.6), who compete within team sports, to varying levels of competition, participated in this study. Three trials for each of the five tests were recorded. All tests had high (intraclass correlation coefficient) test–retest reliability (r = 0.88–0.95) and low typical percentage error (1.95–2.40%). The principle component factor analysis resulted in the extraction of one significant component which explained 89.52% of the total variance. All selected tests were positively and strongly correlated (r = 0.84–0.89). Based upon the results of this study, it was concluded that all tests are highly reliable and valid measures of CODS, with all tests assessing a general athletic ability to change direction. Future research should investigate the factorial validity of the CODS test within homogenous samples.
A series of rhenium diimine carbonyl complexes was prepared and characterized in order to examine the influence of axial ligands on electronic structure. Systematic substitution of the axial carbonyl ...and acetonitrile ligands of Re(deeb)(CO)3(NCCH3)+ (deeb = 4,4′-diethylester-2,2′-bipyridine) with trimethylphosphine and chloride, respectively, gives rise to red-shifted absorbance features. These bathochromic shifts result from destabilization of the occupied d-orbitals involved in metal-to-ligand charge-transfer transitions. Time-Dependent Density Functional Theory identified the orbitals involved in each transition and provided support for the changes in orbital energies induced by ligand substitution.
ABSTRACT We present 0 4 resolution extinction-independent distributions of star formation and dust in 11 star-forming galaxies (SFGs) at z = 1.3-3.0. These galaxies are selected from sensitive ...blank-field surveys of the 2′ × 2′ Hubble Ultra-Deep Field at λ = 5 cm and 1.3 mm using the Karl G. Jansky Very Large Array and Atacama Large Millimeter/submillimeter Array. They have star formation rates (SFRs), stellar masses, and dust properties representative of massive main-sequence SFGs at z ∼ 2. Morphological classification performed on spatially resolved stellar mass maps indicates a mixture of disk and morphologically disturbed systems; half of the sample harbor X-ray active galactic nuclei (AGNs), thereby representing a diversity of z ∼ 2 SFGs undergoing vigorous mass assembly. We find that their intense star formation most frequently occurs at the location of stellar-mass concentration and extends over an area comparable to their stellar-mass distribution, with a median diameter of 4.2 1.8 kpc. This provides direct evidence of galaxy-wide star formation in distant blank-field-selected main-sequence SFGs. The typical galactic-average SFR surface density is 2.5 M yr−1 kpc−2, sufficiently high to drive outflows. In X-ray-selected AGN where radio emission is enhanced over the level associated with star formation, the radio excess pinpoints the AGNs, which are found to be cospatial with star formation. The median extinction-independent size of main-sequence SFGs is two times larger than those of bright submillimeter galaxies, whose SFRs are 3-8 times larger, providing a constraint on the characteristic SFR (∼300 M yr−1) above which a significant population of more compact SFGs appears to emerge.
In patients with hypertrophic cardiomyopathy (HC), atrial fibrillation (AF) is common, often poorly tolerated and difficult to treat. Limited data exists regarding safety or efficacy of drug therapy ...for AF rhythm control in HC patients. We performed a retrospective analysis of patients with HC followed >6 months, treated with amiodarone, sotalol, dofetilide, or disopyramide for rhythm control of non-postoperative AF. The duration followed on each medication, reasons for discontinuing, and incidences of adverse events were recorded. Confounding factors including maximum ventricular septal thickness, age, left ventricular ejection fraction, and gender were assessed. Ninety-eight patients had 130 drug treatments (defined as a continuous time on 1 drug); 23 patients were treated with >1 medication. The probability of remaining on a single antiarrhythmic drug at 1 year was 62% and at 3 was 42%. Maximum ventricular septal thickness (hazard ratio 1.05, p = 0.03) and presence of resting outflow gradient (hazard ratio 2.50, p = 0.002) were associated with discontinuation of therapy. Patients treated with amiodarone or sotalol had no serious safety events suggesting that these medications may be reasonably safe. Amiodarone was least likely to be discontinued for inefficacy (8.5%), but likely to be discontinued for side effects (19%). The probability of remaining on sotalol was 74% at 1 year and 50.0% at 3 and it was only discontinued for side effects in 2%. A small number of patients were treated with disopyramide and dofetilide. In conclusion, our data suggest that amiodarone and sotalol are likely safe, and that sotalol may be particularly attractive given its low rate of side effects and low rate of discontinuation.
Epilepsy is a common neurological disorder affecting approximately 1% of the population. Mutations in voltage‐gated sodium channels are responsible for several monogenic epilepsy syndromes. More than ...800 mutations in the voltage‐gated sodium channel SCN1A have been reported in patients with generalized epilepsy with febrile seizures plus and Dravet syndrome. Heterozygous loss‐of‐function mutations in SCN1A result in Dravet syndrome, a severe infant‐onset epileptic encephalopathy characterized by intractable seizures, developmental delays and increased mortality. A common feature of monogenic epilepsies is variable expressivity among individuals with the same mutation, suggesting that genetic modifiers may influence clinical severity. Mice with heterozygous deletion of Scn1a (Scn1a+/−) model a number of Dravet syndrome features, including spontaneous seizures and premature lethality. Phenotype severity in Scn1a+/− mice is strongly dependent on strain background. On the 129S6/SvEvTac strain Scn1a+/− mice exhibit no overt phenotype, whereas on the (C57BL/6J × 129S6/SvEvTac)F1 strain Scn1a+/− mice exhibit spontaneous seizures and early lethality. To systematically identify loci that influence premature lethality in Scn1a+/− mice, we performed genome scans on reciprocal backcrosses. Quantitative trait locus mapping revealed modifier loci on mouse chromosomes 5, 7, 8 and 11. RNA‐seq analysis of strain‐dependent gene expression, regulation and coding sequence variation provided a list of potential functional candidate genes at each locus. Identification of modifier genes that influence survival in Scn1a+/− mice will improve our understanding of the pathophysiology of Dravet syndrome and may suggest novel therapeutic strategies for improved treatment of human patients.
Genetic mapping identified modifier loci influencing premature lethality in a mouse model of Dravet syndrome, a severe infant‐onset epileptic encephalopathy.
Abstract Background Cardiac sarcoidosis is an inflammatory cardiomyopathy characterized by non-caseating granuloma formation. Diagnosis of cardiac sarcoidosis can be challenging, but ...18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) imaging plays a critical role by identifying abnormal hypermetabolism in myocardium from inflammatory cells. Quantification of myocardial hypermetabolism plays an important role in diagnosis and risk stratification but currently is associated with observer variability due to subjective placement of regions of interests and varied uptake of the FDG in the myocardium. We evaluated a fully automated method for quantifying FDG PET activity using deep learning segmentation of the coregistered CT attenuation maps. Methods We identified 63 patients with suspected cardiac sarcoidosis who underwent FDG PET/CT, including only the first study for each patient. A foundational deep learning model was used to automatically segment all myocardial chambers and left ventricular myocardium from computed tomography (CT) attenuation imaging. Those segmentations were transferred to FDG PET images to automatically quantify maximal standardized uptake values (SUVmax) in myocardium, target to background (left atrium) ratio (TBR), volume of inflammation (VOI) and cardiometabolic activity (CMA) (Figure 1 A). We evaluated the diagnostic accuracy of these measures for cardiac sarcoidosis, with diagnosis based on Japanese Ministry of Health and Wellness criteria. Results A total of 63 patients were included, with mean age 56.7 ± 13.5 and 39 (61.9%) male patients. Cardiac sarcoidosis was present in 24 (38.1%) patients. Fully automated quantification was performed in ~16 seconds per patient. Patients with cardiac sarcoidosis had higher median SUVmax (7.0 vs 4.3, p=0.001), TBR (2.7 vs 1.3, p<0.001), VOI (45 mL vs 1mL, p<0.001), and CMA (203 vs 0, p<0.001). VOI (0.910, 95% CI 0.841 – 0.979, p=0.016) and CMA (0.908, 95% CI 0.837 – 0.979, p=0.011) had significantly higher area under the receiver operating characteristic curve compared to SUVmax (0.740, 95% CI 0.599 – 0.882) (Figure 1B). Conclusions We demonstrate that fully automated quantification of FDG PET for cardiac sarcoidosis based on segmentation of CT attenuation maps is feasible, rapid, and has high diagnostic accuracy. This approach could be applied to provide objective and reproducible measurements of cardiac hypermetabolism to aid in diagnosis or follow response to therapy.
We report the result of a blinded search for weakly interacting massive particles (WIMPs) using the majority of the SuperCDMS Soudan data set. With an exposure of 1690 kg d, a single candidate event ...is observed, consistent with expected backgrounds. This analysis (combined with previous Ge results) sets an upper limit on the spin-independent WIMP-nucleon cross section of 1.4×10^{-44} (1.0×10^{-44}) cm^{2} at 46 GeV/c^{2}. These results set the strongest limits for WIMP-germanium-nucleus interactions for masses >12 GeV/c^{2}.
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To determine if longitudinal associations exist between parental incarceration (PI) and health care use or health behaviors among a national sample of young adults.
We used the National Longitudinal ...Survey of Adolescent to Adult Health to examine associations between history of mother incarceration (MI) and father incarceration (FI), health care use, and 3 dimensions of health behaviors (eg, general health behaviors, substance use, and other risky behaviors) (
= 13 084). Multivariable logistic regression models accounted for individual, family, and geographic factors and generated adjusted odds ratios (aORs).
Over 10% of the sample had a history of PI before the age of 18. History of MI and FI were both associated with forgone health care (aOR = 1.65 95% confidence interval (CI), 1.20-2.27, aOR = 1.22 95% CI, 1.02-1.47, respectively), prescription drug abuse (MI aOR = 1.61 95% CI, 1.02-2.55, FI aOR = 1.46 95% CI, 1.20-1.79), and 10 or more lifetime sexual partners (MI aOR = 1.55 95% CI, 1.08-2.22, FI aOR = 1.19 95% CI, 1.01-1.41). MI was associated with higher likelihood of emergency department use (aOR = 2.36 95% CI, 1.51-3.68), and FI was associated with illicit injection drug use (aOR = 2.54 95% CI, 1.27-5.12).
The effects of incarceration extend beyond incarcerated individuals. PI histories are associated with lower health care use and unhealthy behaviors in young adulthood. By addressing barriers to health care and health-harming behaviors, health care providers and policy makers may reduce health disparities among this population.
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