Accurate Modeling of Ejection Fraction and Stroke Volume With Mobile Phone Auscultation: Prospective Case-Control Study.

BACKGROUND: Heart failure (HF) contributes greatly to morbidity, mortality, and health care costs worldwide. Hospital readmission rates are tracked closely and determine federal reimbursement dollars. No current modality or technology allows for accurate measurement of relevant HF parameters in ambulatory, rural, or underserved settings. This limits the use of telehealth to diagnose or monitor HF in ambulatory patients. OBJECTIVE: This study describes a novel HF diagnostic technology using audio recordings from a standard mobile phone. METHODS: This prospective study of acoustic microphone recordings enrolled convenience samples of patients from 2 different clinical sites in 2 separate areas of the United States. Recordings were obtained at the aortic (second intercostal) site with the patient sitting upright. The team used recordings to create predictive algorithms using physics-based (not neural networks) models. The analysis matched mobile phone acoustic data to ejection fraction (EF) and stroke volume (SV) as evaluated by echocardiograms. Using the physics-based approach to determine features eliminates the need for neural networks and overfitting strategies entirely, potentially offering advantages in data efficiency, model stability, regulatory visibility, and physical insightfulness. RESULTS: Recordings were obtained from 113 participants. No recordings were excluded due to background noise or for any other reason. Participants had diverse racial backgrounds and body surface areas. Reliable echocardiogram data were available for EF from 113 patients and for SV from 65 patients. The mean age of the EF cohort was 66.3 (SD 13.3) years, with female patients comprising 38.3% (43/113) of the group. Using an EF cutoff of ≤40% versus >40%, the model (using 4 features) had an area under the receiver operating curve (AUROC) of 0.955, sensitivity of 0.952, specificity of 0.958, and accuracy of 0.956. The mean age of the SV cohort was 65.5 (SD 12.7) years, with female patients comprising 34% (38/65) of the group. Using a clinically relevant SV cutoff of <50 mL versus >50 mL, the model (using 3 features) had an AUROC of 0.922, sensitivity of 1.000, specificity of 0.844, and accuracy of 0.923. Acoustics frequencies associated with SV were observed to be higher than those associated with EF and, therefore, were less likely to pass through the tissue without distortion. CONCLUSIONS: This work describes the use of mobile phone auscultation recordings obtained with unaltered cellular microphones. The analysis reproduced the estimates of EF and SV with impressive accuracy. This technology will be further developed into a mobile app that could bring screening and monitoring of HF to several clinical settings, such as home or telehealth, rural, remote, and underserved areas across the globe. This would bring high-quality diagnostic methods to patients with HF using equipment they already own and in situations where no other diagnostic and monitoring options exist.

Coastal El Niño triggers rapid marine silicate alteration on the seafloor.

Marine silicate alteration plays a key role in the global carbon and cation cycles, although the timeframe of this process in response to extreme weather events is poorly understood. Here we investigate surface sediments across the Peruvian margin before and after extreme rainfall and runoff (coastal El Niño) using Ge/Si ratios and laser-ablated solid and pore fluid Si isotopes (δ30Si). Pore fluids following the rainfall show elevated Ge/Si ratios (2.87 µmol mol-1) and δ30Si values (3.72‰), which we relate to rapid authigenic clay formation from reactive terrigenous minerals delivered by continental runoff. This study highlights the direct coupling of terrestrial erosion and associated marine sedimentary processes. We show that marine silicate alteration can be rapid and highly dynamic in response to local weather conditions, with a potential impact on marine alkalinity and CO2-cycling on short timescales of weeks to months, and thus element turnover on human time scales.

Quantifying beryllium concentrations in plant shoots from forest ecosystems using cation-exchange chromatography and quadrupole ICP-MS.

Beryllium (Be) is known to be one of the most toxic elements but at the same time exerts a stimulating effect on plant growth. Despite this contradiction, little is known about the Be metabolism in living organisms, partially because of the low amounts present and because the analysis of Be in plants by ICP-MS remains challenging. The challenges arise from the complex organic matrix, the low abundance of Be relative to the other plant essential elements, and the matrix effects resulting thereof in the plasma. To address these challenges, we developed and evaluated a new method for Be concentration analysis in plant material. Key is the quantitative separation of Be from the other matrix elements by cation-exchange chromatography. The new method was verified by processing seven reference materials representing different plant matrices yielding a long-term reproducibility of 16% (RSD). Applying the method, Be concentrations in tree, shrub, bush, and grass samples grown in non-polluted ecosystems from four temperate forests and a tropical rainforest were measured. The Be concentrations in different plant organs range from 0.01 to 63 ng/g that suggest a natural baseline for Be concentrations of 52 ng/g (95 percentile of non-woody tissue) that may serve as bioindicator for Be pollution in the environment. Comparison of Be concentrations in plants with the soil's biologically available fraction revealed that Be is discriminated from uptake into shoots and thus can be considered as non-essential.

Posterior Reversible Encephalopathy Syndrome Presenting as Stroke Mimic.

We present the case of a 33-year-old male with end stage renal disease presenting to the emergency department (ED) with headache, dizziness, and unilateral weakness. Initial concern was for ischemic or hemorrhagic stroke. Magnetic resonance imaging confirmed posterior reversible encephalopathy syndrome (PRES). The patient was treated appropriately and made a full neurologic recovery. PRES is an under-recognized diagnosis in the ED. As a stroke mimic, PRES can lead the clinician on an incorrect diagnostic pathway with potential for iatrogenic harm.

Development of routines for simultaneous in situ chemical composition and stable Si isotope ratio analysis by femtosecond laser ablation inductively coupled plasma mass spectrometry.

Stable metal (e.g. Li, Mg, Ca, Fe, Cu, Zn, and Mo) and metalloid (B, Si, Ge) isotope ratio systems have emerged as geochemical tracers to fingerprint distinct physicochemical reactions. These systems are relevant to many Earth Science questions. The benefit of in situ microscale analysis using laser ablation (LA) over bulk sample analysis is to use the spatial context of different phases in the solid sample to disclose the processes that govern their chemical and isotopic compositions. However, there is a lack of in situ analytical routines to obtain a samples' stable isotope ratio together with its chemical composition. Here, we evaluate two novel analytical routines for the simultaneous determination of the chemical and Si stable isotope composition (δ(30)Si) on the micrometre scale in geological samples. In both routines, multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) is combined with femtosecond-LA, where stable isotope ratios are corrected for mass bias using standard-sample-bracketing with matrix-independent calibration. The first method is based on laser ablation split stream (LASS), where the laser aerosol is split and introduced simultaneously into both the MC-ICP-MS and a quadrupole ICP-MS. The second method is based on optical emission spectroscopy using direct observation of the MC-ICP-MS plasma (LA-MC-ICP-MS|OES). Both methods are evaluated using international geological reference materials. Accurate and precise Si isotope ratios were obtained with an uncertainty typically better than 0.23‰, 2SD, δ(30)Si. With both methods major element concentrations (e.g., Na, Al, Si, Mg, Ca) can be simultaneously determined. However, LASS-ICP-MS is superior over LA-MC-ICP-MS|OES, which is limited by its lower sensitivity. Moreover, LASS-ICP-MS offers trace element analysis down to the µg g(-1)-range for more than 28 elements due to lower limits of detection, and with typical uncertainties better than 15%. For in situ simultaneous stable isotope measurement and chemical composition analysis LASS-ICP-MS in combination with MC-ICP-MS is the method of choice.

Malignant solitary fibrous tumour of the bronchus.

Solitary fibrous tumours most commonly present in the pleura, but have been reported in other extrapleural sites. We present a case of an elderly female who was found to have a malignant solitary fibrous tumour of the right upper lobe bronchus, treated with thoracoscopic lobectomy and bronchoplastic closure.

Mass quantification of nanoparticles by single droplet calibration using inductively coupled plasma mass spectrometry.

Utilization of metallic engineered nanoparticles (ENP) is progressing rapidly; therefore, characterization of their most important properties, e.g., size/mass, elemental composition, and number concentration, is inevitable and currently uses a set of different techniques. In this work, a new setup is proposed for the quantitative size and mass determination of ENPs employing a monodisperse microdroplet generator (MDG) with transport efficiencies >95% coupled to an ICPMS. Two different MDG sample introduction configurations (vertical and horizontal) were tested, and their performance characteristics were evaluated. Due to a 5-fold reduced temporal jitter resulting in a shorter measurement time, the horizontal droplet introduction approach was used for the analysis of ENPs. With this setup, the quantification of Au, Ag, and CeO2 nanoparticles of different sizes and polydispersities was achieved. Results are compared to complementary techniques such as transmission electron microscopy (TEM) and asymmetric flow field flow fractionation (AF4), and advantages as well as limitations of this newly proposed technique are discussed.

Ocular problems in low-income and minority children.

PURPOSE: To report the prevalence rates of screen failures for uncorrected refractive error, abnormal or excessive levels of hyperopia, problems in binocular vision, and deficiency of near point acuity as related to age and ethnicity in children. METHODS: Vision screening tests were administered to 9,743 African-American, Hispanic, and white children aged 6 to 11 years in the Kansas City (United States) metropolitan area. Screening was performed by health professions students using HOTV charts for refractive errors, hyperopia, and near point acuity and a Random Dot E test for binocular vision. Children were screened in their elementary schools, located in primarily poor, urban neighborhoods. The main outcome measure was pass/fail outcomes from screenings, with confirmation of screen fails by licensed health care professionals. RESULTS: For African-American children, 14.1% failed one or more vision screening tests. The corresponding screen failure rates for Hispanic and white children were 14.2% and 11.0%, respectively. There were significant differences in screening failure rates as a function of age and ethnicity, depending on the specific test. The highest rates of screen failures occurred in the 9 to 11 year old age range. CONCLUSIONS: Vision screening failures were frequently associated with age and ethnicity. Screening performed by health professions students can successfully identify potential visual problems at rates similar to those reported in studies using more complex, sophisticated testing performed by specially trained individuals.