The single RRM domain-containing protein SARP1 is required for establishment of the separation zone in Arabidopsis.

Abscission is the shedding of plant organs in response to developmental and environmental cues. Abscission involves cell separation between two neighboring cell types, residuum cells (RECs) and secession cells (SECs) in the floral abscission zone (AZ) in Arabidopsis thaliana. However, the regulatory mechanisms behind the spatial determination that governs cell separation are largely unknown. The class I KNOTTED-like homeobox (KNOX) transcription factor BREVIPEDICELLUS (BP) negatively regulates AZ cell size and number in Arabidopsis. To identify new players participating in abscission, we performed a genetic screen by activation tagging a weak complementation line of bp-3. We identified the mutant ebp1 (enhancer of BP1) displaying delayed floral organ abscission. The ebp1 mutant showed a concaved surface in SECs and abnormally stacked cells on the top of RECs, in contrast to the precisely separated surface in the wild-type. Molecular and histological analyses revealed that the transcriptional programming during cell differentiation in the AZ is compromised in ebp1. The SECs of ebp1 have acquired REC-like properties, including cuticle formation and superoxide production. We show that SEPARATION AFFECTING RNA-BINDING PROTEIN1 (SARP1) is upregulated in ebp1 and plays a role in the establishment of the cell separation layer during floral organ abscission in Arabidopsis.

A Raf-like kinase is required for smoke-induced seed dormancy in Arabidopsis thaliana.

Plants sense and integrate diverse stimuli to determine the timing for germination. A smoke compound, 3,4,5-trimethylfuran-2(5H)-one (trimethylbutenolide, TMB), has been identified to inhibit the seed germination of higher plants. To understand the mode of action, we examined various physiological and molecular aspects of the TMB-dependent inhibition of seed germination in Arabidopsis thaliana The results indicated that the effect of TMB is due to the enhanced physiological dormancy, which is modulated by other dormancy regulatory cues such as after-ripening, stratification, and ABA/GA signaling. In addition, gene expression profiling showed that TMB caused genome-wide transcriptional changes, altering the expression of a series of dormancy-related genes. Based on the TMB-responsive physiological contexts in Arabidopsis, we performed mutant screening to isolate genetic components that underpin the TMB-induced seed dormancy. As a result, the TMB-RESISTANT1 (TES1) gene in Arabidopsis, encoding a B2 group Raf-like kinase, was identified. Phenotypic analysis of the tes1 mutant implicated that TES1 has a critical role in the TMB-responsive gene expression and the inhibition of seed germination. Taken together, we propose that plants have been equipped with a TMB sensory pathway through which the TMB induces the seed dormancy in a TES1-dependent way.

Nature-Derived Polysaccharide-Based Composite Hydrogels for Promoting Wound Healing.

Numerous innovative advancements in dressing technology for wound healing have emerged. Among the various types of wound dressings available, hydrogel dressings, structured with a three-dimensional network and composed of predominantly hydrophilic components, are widely used for wound care due to their remarkable capacity to absorb abundant wound exudate, maintain a moisture environment, provide soothing and cooling effects, and mimic the extracellular matrix. Composite hydrogel dressings, one of the evolved dressings, address the limitations of traditional hydrogel dressings by incorporating additional components, including particles, fibers, fabrics, or foams, within the hydrogels, effectively promoting wound treatment and healing. The added elements enhance the features or add specific functionalities of the dressings, such as sensitivity to external factors, adhesiveness, mechanical strength, control over the release of therapeutic agents, antioxidant and antimicrobial properties, and tissue regeneration behavior. They can be categorized as natural or synthetic based on the origin of the main components of the hydrogel network. This review focuses on recent research on developing natural polysaccharide-based composite hydrogel wound dressings. It explores their preparation and composition, the reinforcement materials integrated into hydrogels, and therapeutic agents. Furthermore, it discusses their features and the specific types of wounds where applied.

Identification of combinations of endocrine disrupting chemicals in household chemical products that require mixture toxicity testing.

People are exposed to various chemicals contained in consumer products for which the risks are poorly characterized. There is growing evidence that exposure to endocrine disrupting chemicals (EDCs) through product use potentially affects development, behavior, and reproduction. However, limited information is available about common combinations of chemicals based on their appearance and potential health effects. The present study listed the ingredients contained in 11064 household chemical products from a publicly available database, and identified EDCs related to estrogenicity, androgenicity, thyroid hormone disruption, and changes in steroidogenesis. Association rule mining was applied to the dataset to identify frequent combinations of chemicals or commonly occurring EDCs contained in a single product. Among the target products, ingredient names were matched with 1241 chemical identifiers. A total of 293 chemicals were related to endocrine disruption, and nearly two-thirds of the products contained more than one of these chemicals. Cleaning products, synthetic detergents, fabric softeners, air fresheners, and deodorants have several hotspots for fragrances, isothiazolinones, glycol ethers, and parabens. The three most prevalent EDCs in household chemical products were added to act as fragrances and preservatives. The present study demonstrated that commonly occurring chemical combinations can be derived using an association rule mining algorithm. The results of this study will be useful in prioritizing chemical combinations and developing management plans for EDC mixture in consumer products.

Point-of-care blood analysis of hypotensive patients in the emergency department.

OBJECTIVE: The aim of this study is to compare a point-of-care (POC) analysis, Enterprise POC (epoc), using the capillary blood obtained from skin puncture with conventional laboratory tests using arterial and venous blood in hypotensive patients. METHODS: This study was conducted at the emergency department of a tertiary care hospital between June and November 2018. 231 hypotensive patients were enrolled. Three types of blood samples (capillary blood from skin puncture and arterial and venous blood from blood vessel puncture) were collected and analyzed. We compared a total of 13 parameters (pH, pCO2, pO2, HCO3-, Ca2+, lactate, Na+, K+, Cl-, glucose, Hb, Hct, and creatinine) between the POC analysis and reference analyzers by performing the equivalence test and Bland-Altman plot analysis. RESULTS: In hypotensive patients, with the exception of two parameters (pCO2, pO2), the pH, HCO3-, Ca2+, lactate, Na+, K+, Cl-, glucose, Hb, Hct, and creatinine parameters measured by the POC analysis were equivalent to or correlated with the reference values. In the patients with cardiac arrest group, nine parameters (pH, HCO3-, Ca2+, Na+, K+, glucose, Hb, Hct, and creatinine) analyzed by the epoc system were equivalent to the reference values. CONCLUSION: Most parameters, except pO2, measured by the epoc system using the capillary blood in hypotensive patients were equivalent to or correlated with those measured by the reference analyzers.

PACLOBUTRAZOL-RESISTANCE Gene Family Regulates Floral Organ Growth with Unequal Genetic Redundancy in Arabidopsis thaliana.

A PACLOBUTRAZOL-RESISTANCE (PRE) gene family, consisting of six genes in Arabidopsis thaliana, encodes a group of helix-loop-helix proteins that act in the growth-promoting transcriptional network. To delineate the specific role of each of the PRE genes in organ growth, we took a reverse genetic approach by constructing high order pre loss-of-function mutants of Arabidopsis thaliana. In addition to dwarf vegetative growth, some double or high order pre mutants exhibited defective floral development, resulting in reduced fertility. While pre2pre5 is normally fertile, both pre2pre6 and pre5pre6 showed reduced fertility. Further, the reduced fertility was exacerbated in the pre2pre5pre6 mutant, indicative of the redundant and critical roles of these PREs. Self-pollination assay and scanning electron microscopy analysis showed that the sterility of pre2pre5pre6 was mainly ascribed to the reduced cell elongation of anther filament, limiting access of pollens to stigma. We found that the expression of a subset of flower-development related genes including ARGOS, IAA19, ACS8, and MYB24 was downregulated in the pre2pre5pre6 flowers. Given these results, we propose that PREs, with unequal functional redundancy, take part in the coordinated growth of floral organs, contributing to successful autogamous reproduction in Arabidopsis thaliana.

A missense allele of KARRIKIN-INSENSITIVE2 impairs ligand-binding and downstream signaling in Arabidopsis thaliana.

A smoke-derived compound, karrikin (KAR), and an endogenous but as yet unidentified KARRIKIN INSENSITIVE2 (KAI2) ligand (KL) have been identified as chemical cues in higher plants that impact on multiple aspects of growth and development. Genetic screening of light-signaling mutants in Arabidopsis thaliana has identified a mutant designated as ply2 (pleiotropic long hypocotyl2) that has pleiotropic light-response defects. In this study, we used positional cloning to identify the molecular lesion of ply2 as a missense mutation of KAI2/HYPOSENSITIVE TO LIGHT, which causes a single amino acid substitution, Ala219Val. Physiological analysis and genetic epistasis analysis with the KL-signaling components MORE AXILLARY GROWTH2 (MAX2) and SUPPRESSOR OF MAX2 1 suggested that the pleiotropic phenotypes of the ply2 mutant can be ascribed to a defect in KL-signaling. Molecular and biochemical analyses revealed that the mutant KAI2ply2 protein is impaired in its ligand-binding activity. In support of this conclusion, X-ray crystallography studies suggested that the KAI2ply2 mutation not only results in a narrowed entrance gate for the ligand but also alters the structural flexibility of the helical lid domains. We discuss the structural implications of the Ala219 residue with regard to ligand-specific binding and signaling of KAI2, together with potential functions of KL-signaling in the context of the light-regulatory network in Arabidopsis thaliana.

Improvement of Liquid Crystal Alignment Using Novel Photo-Activators.

Photo-activator is a kind of additive that can improve the anchoring energy by attacking some of the bonds of polyimide (PI). Photo-activators were synthesized from the reaction of cyclohexanone oxime with three different anhydrides, respectively. Each activator generates different active radicals when irradiated. These fragmented and activated radicals are responsible for the liquid crystal (LC) alignment of PI film. The reactivity was confirmed through UV-Visible spectroscopy. All the three photo-activators had characteristic bimodal-shaped absorption peaks at 270∼280 nm. The photofragmentation reactions were completed within 1 min of UV irradiation, which implies that the activators are highly reactive to UV light. The short reaction time is very useful for liquid crystal display (LCD) factory applications. The photo-activator using crotonic anhydride (CAP) showed the highest surface anchoring energy, of 6.92 × 10-5 J/m2, compared to that of the other activators and that obtained by rubbing methods; (1.11 × 10-5 J/m2). This result was obtained due to resonance stabilization from the allyl radicals of CAP. The photo-activator using acetic anhydride (AAP) reached its maximum anchoring energy in less than 3 min of irradiation, which is the shortest optimum irradiation time. Considering the fact that this process does not require additional procedure and time, the photo-activators can be considered an innovate additive.

Genetic identification of ACC-RESISTANT2 reveals involvement of LYSINE HISTIDINE TRANSPORTER1 in the uptake of 1-aminocyclopropane-1-carboxylic acid in Arabidopsis thaliana.

1-Aminocyclopropane-1-carboxylic acid (ACC) is a biosynthetic precursor of ethylene, a gaseous plant hormone which controls a myriad of aspects of development and stress adaptation in higher plants. Here, we identified a mutant in Arabidopsis thaliana, designated as ACC-resistant2 (are2), displaying a dose-dependent resistance to exogenously applied ACC. Physiological analyses revealed that mutation of are2 impaired various aspects of exogenous ACC-induced ethylene responses, while not affecting sensitivity to other plant hormones during seedling development. Interestingly, the are2 mutant was normally sensitive to gaseous ethylene, compared with the wild type. Double mutant analysis showed that the ethylene-overproducing mutations, eto1 or eto3, and the constitutive ethylene signaling mutation, ctr1 were epistatic to the are2 mutation. These results suggest that the are2 mutant is not defective in ethylene biosynthesis or ethylene signaling per se. Map-based cloning of ARE2 demonstrated that LYSINE HISTIDINE TRANSPORTER1 (LHT1), encoding an amino acid transporter, is the gene responsible. An uptake experiment with radiolabeled ACC indicated that mutations of LHT1 reduced, albeit not completely, uptake of ACC. Further, we performed an amino acid competition assay and found that two amino acids, alanine and glycine, known as substrates of LHT1, could suppress the ACC-induced triple response in a LHT1-dependent way. Taken together, these results provide the first molecular genetic evidence supporting that a class of amino acid transporters including LHT1 takes part in transport of ACC, thereby influencing exogenous ACC-induced ethylene responses in A. thaliana.

The current trend of emergency airway management: a clinical review.

Airway management is a fundamental and intricate process that involves a sequence of integrated tasks. Situations requiring emergency airway management may occur in emergency department, intensive care units, and various other spaces. Emergency airway management can face a variety of challenges during preparation, intubation, and post-intubation, and may result in significant complications for the patients. Therefore, many countries are establishing step-by-step systemization and detailed guidelines, and updating the content based on the latest research. This clinical review introduces the current trends in emergency airway management, such as emergency airway management algorithms, comparison of video and direct laryngoscopy, rapid sequence intubation, pediatric airway management, pre-hospital airway management, surgical airway management, and airway management education.

Identification and quantification of acetyl tributyl citrate (ATBC) metabolites using human liver microsomes and human urine.

Plasticizers are chemicals that make plastics flexible, and phthalates are commonly used. Due to the toxic effects of phthalates, there is increasing use of non-phthalate plasticizers like acetyl tributyl citrate (ATBC). ATBC has emerged as a safer alternative, yet concerns about its long-term safety persist due to its high leachability and potential endocrine-disrupting effects. This study aims to identify ATBC metabolites using human liver microsomes and suspect screening methods, and to explore potential urinary biomarkers for ATBC exposure. Using ultra-high-performance liquid chromatography coupled with high-resolution mass spectrometry, we identified ATBC metabolites, including acetyl dibutyl citrate (ADBC), tributyl citrate (TBC), and dibutyl citrate (DBC). Urine samples from 15 participants revealed the presence of ADBC in 5, TBC in 11, and DBC in all samples, with DBC concentrations pointedly higher than the other metabolites. These metabolites show promise as biomarkers for ATBC exposure, though further validation with human data is required. Our results underscore the need for comprehensive studies on ATBC metabolism, exposure pathways, and urinary excretion to accurately assess human exposure levels.

Hemolysis Control in the Emergency Department by Interventional Blood Sampling.

The hemolysis rate in the emergency department (ED) is higher compared to that in other departments. We propose a new blood sampling technique without repeated venipuncture to reduce hemolysis and compare the hemolysis rate between blood collected by this method and that collected with an intravenous (IV) catheter. This prospective study included a nonconsecutive sample of patients visiting the ED (aged ≥ 18 years) of a tertiary urban university hospital. The intravenous catheterization was performed by three pre-trained nurses. The new blood collection technique involved sample collection without removing the catheter needle, performed immediately before the conventional method (through an IV catheter), without additional venipuncture. Two blood samples were collected from each patient using both the new and conventional methods, and the hemolysis index was evaluated. We compared the hemolysis rate between the two methods. From the 260 patients enrolled in this study, 147 (56.5%) were male, and the mean age was 58.3 years. The hemolysis rate of the new blood collection method was 1.9% (5/260), which was significantly lower than that of the conventional method (7.3%; 19/260) (p = 0.001). The new blood collection method can reduce the hemolysis rate as compared to the conventional blood collection method.

Blood Microbiota Profile Is Associated with the Responsiveness of Postprandial Lipemia to Platycodi radix Beverage: A Randomized Controlled Trial in Healthy Subjects.

Prolonged postprandial hyperlipidemia may cause the development of cardiovascular diseases. This study explored whether postprandial triglyceride-rich lipoprotein (TRL) clearance responsiveness to Platycodi radix beverage (PR) is associated with changes in blood microbiota profiles. We conducted an 8-week randomized controlled clinical trial involving normolipidemic adults with low fruit and vegetable intakes. Participants underwent an oral fat tolerance test and 16S amplicon sequencing analysis of blood microbiota. Using the Qualitative Interaction Trees, we identified responders as those with higher baseline dietary fat intake (>38.5 g/day) and lipoprotein lipase levels (>150.6 ng/mL), who showed significant reductions in AUC for triglyceride (TG) and chylomicron-TG after the oral fat tolerance test. The LEfSe analysis showed differentially abundant blood microbiota between responders and non-responders. A penalized logistic regression algorithm was employed to predict the responsiveness to intervention on the TRL clearance based on the background characteristics, including the blood microbiome. Our findings suggest that PR intake can modulate postprandial TRL clearance in adults consuming higher fat intake over 38.5 g/day and low fruit and vegetable intake through shared links to systemic microbial signatures.

Single and mixture toxicity evaluation of avobenzone and homosalate to male zebrafish and H295R cells.

Avobenzone and homosalate are widely used in sunscreens to provide ultraviolet (UV) protection, either as single compounds or in combination. Some UV filters exhibit estrogenic or anti-androgenic activities, however, studies regarding their interactions and toxicity in mixtures are limited. In this study, the effect of the toxicity of a binary mixture comprising avobenzone (0.72 µg L-1) and homosalate (1.02 and 103 µg L-1) on steroid hormone biosynthesis were investigated using male zebrafish and human adrenocortical carcinoma (H295R) cells. In fish exposed to homosalate, a significant decrease in the gonadosomatic index, testosterone level, and transcription of several genes (e.g, hsd3b2, cyp17a1, and hsd17b1) and a significant increase in the hepatosomatic index, liver steatosis, 17ß-estradiol level, and transcription of vtg gene were observed. These results suggest that estrogenic and anti-androgenic effects of homosalate were mediated by the steroidogenic pathway. The presence of 0.72 µg L-1 of avobenzone augmented the anti-androgenic responses in male fish. The testosterone level in the H295R cells were significantly decreased after they were exposed to homosalate alone or in combination with avobenzone, which is consistent with observations in male zebrafish. Further studies need to be conducted to understand the endocrine disrupting properties of long-term exposure to substances typically used in sunscreens.

Psychological Benefits of Purchasing Home Meal Replacement in the Context of Eco-Friendly TV Home Shopping Broadcast: The Moderating Role of Personal Norm.

This study observed the relationship between psychological benefits and the theory of planned behavior (TPB) in the context of an eco-friendly TV home shopping broadcasts. The theoretical framework was enhanced even further by examining the moderating role of personal norm on proenvironmental attitudes in the TV home shopping context. An online survey was conducted with Korean customers who had purchased home meal replacement (HMR) products from a TV home shopping broadcast within the past 6 months. A total of 305 samples were collected and used for the data analysis. All six of the hypotheses in the psychological benefits and TPB model were supported, meaning all constructs of psychological benefits, including warm glow, self-expressive benefits, and nature experiences, impacted TPB and behavioral intentions. Furthermore, personal norm had a moderating role in the relationship between warm glow and attitude. This research provides significant theoretical and managerial implications for the home shopping industry.

Detection of the location of pneumothorax in chest X-rays using small artificial neural networks and a simple training process.

The purpose of this study was to evaluate the diagnostic performance achieved by using fully-connected small artificial neural networks (ANNs) and a simple training process, the Kim-Monte Carlo algorithm, to detect the location of pneumothorax in chest X-rays. A total of 1,000 chest X-ray images with pneumothorax were taken randomly from NIH (the National Institutes of Health) public image database and used as the training and test sets. Each X-ray image with pneumothorax was divided into 49 boxes for pneumothorax localization. For each of the boxes in the chest X-ray images contained in the test set, the area under the receiver operating characteristic (ROC) curve (AUC) was 0.882, and the sensitivity and specificity were 80.6% and 83.0%, respectively. In addition, a common currently used deep-learning method for image recognition, the convolution neural network (CNN), was also applied to the same dataset for comparison purposes. The performance of the fully-connected small ANN was better than that of the CNN. Regarding the diagnostic performances of the CNN with different activation functions, the CNN with a sigmoid activation function for fully-connected hidden nodes was better than the CNN with the rectified linear unit (RELU) activation function. This study showed that our approach can accurately detect the location of pneumothorax in chest X-rays, significantly reduce the time delay incurred when diagnosing urgent diseases such as pneumothorax, and increase the effectiveness of clinical practice and patient care.

Canine hippocampal formation composited into three-dimensional structure using MPRAGE.

This study was performed to anatomically illustrate the living canine hippocampal formation in three-dimensions (3D), and to evaluate its relationship to surrounding brain structures. Three normal beagle dogs were scanned on a MR scanner with inversion recovery segmented 3D gradient echo sequence (known as MP-RAGE: Magnetization Prepared Rapid Gradient Echo). The MRI data was manually segmented and reconstructed into a 3D model using the 3D slicer software tool. From the 3D model, the spatial relationships between hippocampal formation and surrounding structures were evaluated. With the increased spatial resolution and contrast of the MPRAGE, the canine hippocampal formation was easily depicted. The reconstructed 3D image allows easy understanding of the hippocampal contour and demonstrates the structural relationship of the hippocampal formation to surrounding structures in vivo.

De novo assembly and characterization of transcriptome in the medicinal plant Euphorbia jolkini.

BACKGROUND: Euphorbia jolkini, a medicinal herb that grows on the warm beaches in Japan and South Korea, is known to be used for traditional medicines to treat a variety of ailments, including bruises, stiffness, indigestion, toothache, and diabetes. OBJECTIVE: It is to analyze the whole transcriptome and identify the genes related to the phenylpropanoid biosynthesis in the medicinally important herb E jolkini. METHODS: Paired-end Illumina HiSeq™ 2500 sequencing technology was employed for cDNA library construction and Illumina sequencing. Public databases like TAIR (The Arabidopsis Information Resource), Swissprot and KEGG (Kyoto Encyclopedia of Genes and Genomes) were used for annotations of unigenes obtained. RESULTS: The transcriptome of E. jolkini generated 139,215 assembled transcripts with an average length of 868 bp and an N50 value of 1460 bp that were further clustered using CD-HIT into 93,801 unigenes with an average length of 847 bp (N50-1410 bp). Sixty-three percent of the coding sequences (CDS) were annotated from the longest open reading frame (ORF). A remarkable percentage of unigenes were annotated against various databases. The differentially expressed gene analysis revealed that the expression of genes related to the terpenoid backbone biosynthesis pathway was higher in the flowers, whereas that of genes related to the phenylpropanoid biosynthesis pathway was both up- and downregulated in flowers and leaves. A search of against the transcription factor domain found 1023 transcription factors (TFs) that were from 54 TF families. CONCLUSION: Assembled sequences of the E. jolkini transcriptome are made available for the first time in this study E. jolkini and lay a foundation for the investigation of secondary metabolite biosynthesis.

KAI2-KL signaling intersects with light-signaling for photomorphogenesis.

Light is an important environmental cue, causing a high degree of developmental plasticity in higher plants. The outcome of light-regulated developmental response is determined by not only photo-sensory systems but also endogenous physiological contexts in plants. KARRIKIN-INSENSITIVE2 (KAI2) functions as a receptor of karrikin and endogenous, as yet to be identified, KAI2 ligand (KL). The loss-of-function of KAI2 caused light-hyposensitive photomorphogenesis, affecting the expression light-responsive genes under the light conditions. However, it remains still unclear how KAI2-KL signaling interacts with light-signaling. Here, we show that the ply2 mutation, a severe loss-of-function allele of KAI2 affected the expression of a subset of light-responsive genes, irrespectively of light condition. The results implied that the overlapping set of light- and KAI2-responsive genes may serve as an integrating node between light- and KAI2-KL signaling. Further, the results of double mutant analyses between the ply2 mutant and mutants of CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1) or LONG HYPOCOTYL IN FAR-RED (HFR1) implicated that KAI2-KL signaling acts at downstream of COP1, largely independently of HFR1. Together, these results suggest that KAI2-KL signaling intersects with a subset of the light-regulatory network, by which plants adjust their photomorphogenic development.

Learning curve-cumulative summation analysis of visual estimation of left ventricular function in novice practitioners: A STROBE-compliant article.

The aim of the present study was to determine the value of cumulative summation (CUSUM) analysis in assessing the proficiency of novice practitioners in estimating the left ventricular ejection fraction (EF).Seven novice practitioners with no echocardiography experience were recruited in this observational study. Each practitioner assessed EF from echocardiographic video files of 100 cases, one by one, and received feedback and teaching. We obtained a CUSUM score through comparison of the gold standard values of EF and the EF values determined by the practitioners. Then, the practitioners underwent the same test 4 weeks later, except without feedback and teaching, using echocardiographic video files from 100 other cases.The mean number of visual estimation cases required to pass the learning curve (LC)-CUSUM test was 56.3 ±â€Š9.1 (95% CI 47.8-64.7). The LC-CUSUM average of the 7 novice practitioners showed improvement in visual estimation skill, with an average acceptable level achieved after a mean experience of 55 cases. In the test performed after 4 weeks, 5 of the 7 novice practitioners showed significantly good overall agreement. All novice practitioners had a kappa coefficient greater than .8, and significant and almost perfect agreement was observed. All the participants exhibited a percentage of correct answers greater than 81%.We found that the novice practitioners could acquire an acceptable level of skill for estimating EF with short-term, self-learning-focused echocardiographic training.