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1.
Cureus ; 16(7): e65665, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-39205729

RESUMEN

Background and objectives Dual-trained medicine-pediatrics physicians (med-peds) play an important role in the healthcare ecosystem. Little is known about the subspecialty choices of med-peds residency graduates. This study aims to characterize the subspecialty choices of med-peds residency graduates. Methods The Medicine-Pediatrics Program Directors Association (MPPDA) administers an annual survey to the program directors of all med-peds residency programs accredited by the Accreditation Council for Graduate Medical Education (ACGME). This project represents aggregate survey data from 2020-2023. Results The number of program directors responding to the survey ranged from 80.8% (63/78) to 85.7% (66/77; mean response rate: 82.8%). About 465 of 1,245 (37%) graduates over the four years chose fellowship training, across 51 unique subspecialties. The top five selected pathways were: adult pulmonary and critical care 54 (11.6%), allergy and immunology 37 (7.9%), adult infectious diseases 30 (6.5%), adult cardiology 30 (6.5%), and pediatric cardiology 30 (6.5%). Conclusions Med-Peds residents pursue a diversity of subspecialty training and represent an important contribution to the subspecialty workforce. Improving combined subspecialty opportunities may increase participation by med-peds graduates and, in particular, may support the increasing need for pediatric subspecialists.

2.
Med Sci Educ ; 34(3): 601-607, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38887413

RESUMEN

Introduction: Burnout is an increasingly prevalent problem among resident physicians. To address this problem, the Accreditation Council on Graduate Medical Education (ACGME) created the Back to Bedside initiative, supporting resident-driven projects focused on increasing direct interactions with patients. In 2017, Baylor College of Medicine (BCM) Internal Medicine Residency received a Back to Bedside grant to develop and implement "Humanism Rounds," a multifaceted program which sought to promote personal connections between residents and patients and foster reflection about patients' non-clinical stories, with the hopes of reducing burnout and increasing residents' sense of meaning at work. Materials and Methods: Between 2018 and 2020, internal medicine residents were instructed on and encouraged to participate in Humanism Rounds. The program included three components: taking a "human history," bedside rounds focused on non-clinical concerns, and sharing patient stories with colleagues ("celebrations"). Residents were surveyed using institutional and ACGME surveys regarding burnout, meaning at work, and the clinical learning environment. Results: Three hundred eleven institutional (response rate, 74%) and 328 AGCME (response rate, 78%) surveys were completed and analyzed. Residents who actively engaged with Humanism Rounds reported more meaning and fulfillment at work (p < 0.001). During the period of this project, ratings of the learning environment and personal callousness improved among subgroups of residents. Conclusions: Baylor College of Medicine Internal Medicine residents who engaged with Humanism Rounds reported more meaning and fulfillment in their work. This program describes a low-cost model for other specialties and institutions to strengthen human connections and improve residents' experience during training. Supplementary Information: The online version contains supplementary material available at 10.1007/s40670-024-02017-9.

3.
Med Teach ; 46(6): 752-756, 2024 06.
Artículo en Inglés | MEDLINE | ID: mdl-38285894

RESUMEN

The custom GPT is the latest powerful feature added to ChatGPT. Non-programmers can create and share their own GPTs ("chat bots"), allowing Health Professions Educators to apply the capabilities of ChatGPT to create administrative assistants, online tutors, virtual patients, and more, to support their clinical and non-clinical teaching environments. To achieve this correctly, however, requires some skills, and this 12-Tips paper provides those: we explain how to construct data sources, build relevant GPTs, and apply some basic security.


Asunto(s)
Empleos en Salud , Humanos , Empleos en Salud/educación , Internet
4.
Postgrad Med ; 136(1): 44-51, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38193442

RESUMEN

OBJECTIVES: Evidence has shown significant impacts of the COVID-19 pandemic on physicians. We hypothesized that these effects would impact surgical and non-surgical resident education differently, with non-surgical specialties being more heavily impacted by frontline work and surgical specialties losing elective cases. METHODS: We examined well-being and burnout among resident physicians in surgical and non-surgical specialties during the peak of the COVID-19 pandemic using the Mayo Physician Well-Being Index (WBI). RESULTS: Completed surveys were received from 110 residents, 55% of whom were in a surgical training program. 35% of respondents were identified as 'at risk' for burnout. Increased demands from work (adj. OR 3.79, 95% CI 1.50, 9.59, p = 0.005) was associated with an increased likelihood for being 'at risk' compared to those without increased demands. Odds of having increased stress level were higher amongst residents with fear/anxiety of the unknown (adj. OR 4.21, 95% CI 1.63, 10.90, p = 0.003) and more demands outside work (adj. OR 10.54, 95% CI 2.63, 42.16, p = 0.001) but lower amongst residents with more time for studying (OR 0.23, 95% CI 0.09, 0.64, p = 0.005). Risk for burnout was not significantly different between surgical and non-surgical specialties when adjusting for increased demands from work (adj. OR 1.43, 95% CI 0.60, 3.37, p = 0.0.418). CONCLUSION: Perceived effects of the COVID-19 pandemic upon residents' educational experience was mixed: reduced clinical volume had a negative impact, while increased time for study was perceived favorably. These findings suggest potential strategies and targets to mitigate the stress and burnout of a future crisis, whether large or small, among surgical and non-surgical trainees.


Asunto(s)
Agotamiento Profesional , COVID-19 , Internado y Residencia , Médicos , Humanos , COVID-19/epidemiología , Pandemias , Agotamiento Profesional/epidemiología , Encuestas y Cuestionarios
5.
Indian Heart J ; 70(5): 756-757, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30392519
6.
Med Educ Online ; 23(1): 1542922, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-30406730

RESUMEN

BACKGROUND: The Medical Student Performance Evaluation (MSPE) is a primary source of information used by residency programs in their selection of trainees. The MSPE contains a narrative description of the applicant's performance during medical school. In 2002, the Association of American Medical Colleges' guideline for preparation of the MSPE recommended inclusion of a comparative summative assessment of the student's overall performance relative to his/her peers (final adjective). OBJECTIVE: We hypothesize that the inclusion of a final adjective in the MSPE affects a reviewer's assessment of the applicant's desirability more than the narrative description of performance and designed a study to evaluate this hypothesis. DESIGN: Fifty-six faculty members from the Departments of Pediatrics and Medicine with experience reviewing MSPEs as part of the intern selection process reviewed two pairs of mock MSPE letters. In each pair, the narrative in one letter was superior to that in the other. Two final adjectives describing relative class ranks were created. Each subject was first presented with a pair of letters with mismatched final adjective (study), i.e., the letter with the stronger narrative was presented with the weaker final adjective and vice versa. The subject was then presented with a second pair of letters without final adjectives (control). Subjects ranked the relative desirability of the two applicants in each pair. RESULTS: The proportion of rankings congruent with the strength of the narratives under study and control conditions were compared. Subjects were significantly less likely to rank the applicants congruent with the strength of the narratives when the strength of the final adjectives conflicted with the strength of the narrative; 42.9% of study letters were ranked congruent with the narrative versus 82.1% of controls (p = 0.0001). CONCLUSION: The MSPE final adjective had a greater impact than the narrative description of performance on the determination of applicant desirability. ABBREVIATIONS: MSPE: Medical Student Performance Evaluation; AAMC: Association of American Medical Colleges; BCM: Baylor College of Medicine.


Asunto(s)
Conducta de Elección , Competencia Clínica , Evaluación Educacional , Estudiantes de Medicina , Docentes Médicos , Femenino , Humanos , Internado y Residencia , Masculino
7.
Acad Med ; 93(3): 471-477, 2018 03.
Artículo en Inglés | MEDLINE | ID: mdl-28640030

RESUMEN

PURPOSE: To begin to quantify and understand the use of the flipped classroom (FC)-a progressive, effective, curricular model-in internal medicine (IM) education in relation to residency program and program director (PD) characteristics. METHOD: The authors conducted a survey that included the Flipped Classroom Perception Instrument (FCPI) in 2015 regarding programs' use and PDs' perceptions of the FC model. RESULTS: Among the 368 IM residency programs, PDs at 227 (61.7%) responded to the survey and 206 (56.0%) completed the FCPI. Regarding how often programs used the FC model, 34 of the 206 PDs (16.5%) reported "never"; 44 (21.4%) reported "very rarely"; another 44 (21.4%) reported "somewhat rarely"; 59 (28.6%) reported "sometimes"; 16 (7.8%) reported "somewhat often"; and 9 (4.4%) reported "very often." The mean FCPI score (standard deviation [SD]) for the in-class application factor (4.11 [0.68]) was higher (i.e., more favorable) than for the preclass activity factor (3.94 [0.65]) (P < .001). FC perceptions (mean [SD]) were higher among younger PDs (≤ 50 years, 4.12 [0.62]; > 50 years, 3.94 [0.61]; P = .04) and women compared with men (4.28 [0.56] vs. 3.91 [0.62]; P < .001). PDs with better perceptions of FCs had higher odds of using FCs (odds ratio, 4.768; P < .001). CONCLUSIONS: Most IM programs use the FC model at least to some extent, and PDs prefer the interactive in-class components over the independent preclass activities. PDs who are women and younger perceived the model more favorably.


Asunto(s)
Docentes Médicos/psicología , Medicina Interna/educación , Competencia Clínica , Femenino , Humanos , Internado y Residencia , Masculino , Percepción , Evaluación de Programas y Proyectos de Salud , Encuestas y Cuestionarios
9.
BMC Med Educ ; 17(1): 114, 2017 Jul 11.
Artículo en Inglés | MEDLINE | ID: mdl-28697744

RESUMEN

BACKGROUND: E-learning-the use of Internet technologies to enhance knowledge and performance-has become a widely accepted instructional approach. Little is known about the current use of e-learning in postgraduate medical education. To determine utilization of e-learning by United States internal medicine residency programs, program director (PD) perceptions of e-learning, and associations between e-learning use and residency program characteristics. METHODS: We conducted a national survey in collaboration with the Association of Program Directors in Internal Medicine of all United States internal medicine residency programs. RESULTS: Of the 368 PDs, 214 (58.2%) completed the e-learning survey. Use of synchronous e-learning at least sometimes, somewhat often, or very often was reported by 85 (39.7%); 153 programs (71.5%) use asynchronous e-learning at least sometimes, somewhat often, or very often. Most programs (168; 79%) do not have a budget to integrate e-learning. Mean (SD) scores for the PD perceptions of e-learning ranged from 3.01 (0.94) to 3.86 (0.72) on a 5-point scale. The odds of synchronous e-learning use were higher in programs with a budget for its implementation (odds ratio, 3.0 [95% CI, 1.04-8.7]; P = .04). CONCLUSIONS: Residency programs could be better resourced to integrate e-learning technologies. Asynchronous e-learning was used more than synchronous, which may be to accommodate busy resident schedules and duty-hour restrictions. PD perceptions of e-learning are relatively moderate and future research should determine whether PD reluctance to adopt e-learning is based on unawareness of the evidence, perceptions that e-learning is expensive, or judgments about value versus effectiveness.


Asunto(s)
Instrucción por Computador , Curriculum , Educación de Postgrado en Medicina , Internado y Residencia , Adulto , Actitud del Personal de Salud , Educación de Postgrado en Medicina/normas , Educación de Postgrado en Medicina/tendencias , Evaluación Educacional , Femenino , Humanos , Internado y Residencia/organización & administración , Internado y Residencia/normas , Internado y Residencia/tendencias , Masculino , Persona de Mediana Edad , Aprendizaje Basado en Problemas , Evaluación de Programas y Proyectos de Salud , Estados Unidos , Carga de Trabajo
10.
Int J Environ Anal Chem ; 97(3): 264-275, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28626294

RESUMEN

Exposures to beryllium (Be), even at extremely low levels, can cause severe health effects in a percentage of those exposed; consequently, occupational exposure limits (OELs) promulgated for this element are the lowest established for any element. This work describes the advantages of using highly alkaline dye solutions for determination of Be in occupational hygiene and environmental samples by means of an optical molecular fluorescence technique after sample extraction in 1-3% (w˖w-1) aqueous ammonium bifluoride (NH4HF2). Improved attributes include the ability to further enhance the detection limits of Be in extraction solutions of high acidity with minimal dilution, which is particularly beneficial when NH4HF2 solutions of higher concentration are used for extraction of Be from soil samples. Significant improvements in Be method detection limits (MDLs) are obtained at levels many-fold below those reported previously for this methodology. Notably, MDLs for Be of <0.01 ng l-1 / 0.1 ng per sample have been attained, which are superior to MDLs routinely reported for this element by means of the most widely used ultra-trace elemental measurement technique, inductively coupled plasma mass spectrometry (ICP-MS). Very low MDLs for Be are essential in consideration of reductions in OELs for this element in workplace air by health organizations and regulatory agencies in the USA and internationally. Applications of enhanced Be measurements to air filter samples, surface wipe samples, soils and newly-designed occupational air sampler inserts are illustrated.

11.
Am J Cardiol ; 118(2): 162-9, 2016 07 15.
Artículo en Inglés | MEDLINE | ID: mdl-27289292

RESUMEN

The accepted definition of virtual histology intravascular ultrasound (IVUS-VH) thin-cap fibroatheroma (TCFA) is only a modest predictor of plaque rupture (PR). We sought to determine the relation between IVUS-VH findings and culprit lesions with PR using computational analysis. A total of 80 culprit lesions from 80 patients with stable angina (n = 37), unstable angina (n = 20), and myocardial infarction (n = 23) were divided into those with (n = 15) and without PR (n = 65). By use of automated computational analysis, the standard IVUS-VH TCFA criterion and 124 additional criteria were compared. The standard TCFA definition demonstrated modest ability to discriminate lesions with and without PR (sensitivity 87%, specificity 37%, PPV 0.24, and NPV 0.92). Of 124 additional IVUS-VH TCFA definitions, only 2 improved the discriminative ability even modestly. However, a positive correlation was demonstrated between cavity size and necrotic core percentage (r = 0.78, p <0.01) and a negative correlation with percentage of fibrous tissue (r = -0.81, p <0.01). In conclusion, IVUS-VH criteria were only modestly associated with PR, without significant improvement by varying IVUS-VH TCFA features, but IVUS-VH features of ruptured plaques were strongly correlated with cavity size.


Asunto(s)
Angina Estable/diagnóstico por imagen , Angina Inestable/diagnóstico por imagen , Calcinosis/diagnóstico por imagen , Enfermedad de la Arteria Coronaria/diagnóstico por imagen , Infarto del Miocardio/diagnóstico por imagen , Placa Aterosclerótica/diagnóstico por imagen , Rotura Espontánea/diagnóstico por imagen , Anciano , Angina Estable/cirugía , Angina Inestable/cirugía , Calcinosis/patología , Enfermedad de la Arteria Coronaria/cirugía , Femenino , Fibrosis , Humanos , Masculino , Persona de Mediana Edad , Infarto del Miocardio/cirugía , Necrosis , Placa Aterosclerótica/patología , Estudios Retrospectivos , Ultrasonografía Intervencional
13.
J Invasive Cardiol ; 27(9): E196-8, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-26332884

RESUMEN

Coronary artery aneurysm with dissection is an uncommon presentation of Loeys-Dietz syndrome (LDS). Diagnosis and management of patients with LDS who present with unstable clinical syndromes merit special attention given unique pathophysiology derangements associated with this disease entity. Clinical experience in treating such patients is limited to a few case reports, and an optimal catheter-based treatment approach is less well defined. Intravascular imaging techniques, particularly optical coherence tomography (OCT), are able to provide further insight about the morphology of lesions and guide-catheter based intervention. In this case report, we describe one such patient and highlight the key morphological characteristics of coronary artery disease in patients with LDS as well as the crucial role of OCT in its management.


Asunto(s)
Anomalías de los Vasos Coronarios/diagnóstico , Anomalías de los Vasos Coronarios/cirugía , Péptidos y Proteínas de Señalización Intracelular/genética , Síndrome de Loeys-Dietz , Intervención Coronaria Percutánea/métodos , Tomografía de Coherencia Óptica/métodos , Enfermedades Vasculares/congénito , Aneurisma Coronario/complicaciones , Aneurisma Coronario/etiología , Anomalías de los Vasos Coronarios/etiología , Anomalías de los Vasos Coronarios/fisiopatología , Diagnóstico Diferencial , Manejo de la Enfermedad , Humanos , Síndrome de Loeys-Dietz/complicaciones , Síndrome de Loeys-Dietz/diagnóstico , Síndrome de Loeys-Dietz/genética , Síndrome de Loeys-Dietz/fisiopatología , Síndrome de Loeys-Dietz/cirugía , Masculino , Persona de Mediana Edad , Mutación , Enfermedades Vasculares/diagnóstico , Enfermedades Vasculares/etiología , Enfermedades Vasculares/fisiopatología , Enfermedades Vasculares/cirugía
14.
Int J Cardiovasc Imaging ; 31(5): 1011-8, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25761533

RESUMEN

Left atrial size in atrial fibrillation is a strong predictor of successful ablation and cardiovascular events. Cardiac magnetic resonance multislice method (CMR-MSM) is the current gold standard for left atrial volume (LAV) assessment but is time consuming. We investigated whether LAV with more rapid area-length method by echocardiography (Echo-AL) or cardiac magnetic resonance (CMR-AL) and invasive measurement by 3D-CARTO mapping during ablation correlate with the CMR-MSM. We studied 250 consecutive patients prior to atrial fibrillation ablation. CMR images were acquired on 3T scanner to measure LAV by MSM and biplane area-length method. Standard echocardiography views were used to calculate LAV by biplane area-length method. LAV during ablation was measured by 3D-CARTO mapping. LAV was compared using intra-class correlation (ICC), Pearson's correlation and Bland-Altman plots. CMR-MSM was used as the reference standard. Mean LAV using CMR-MSM was 112.7 ± 36.7 ml. CMR-AL method overestimated LAV by 13.3 ± 21.8 ml (11.2%, p < 0.005) whereas 3D-CARTO and Echo-AL underestimated LAV by 8.3 ± 22.6 and 24.0 ± 27.6 ml respectively (8.7% and 20.0% respectively, p < 0.005). There was no significant difference between paroxysmal and persistent atrial fibrillation. CMR-AL and 3D-CARTO correlated and agreed well with CMR-MSM (r = 0.87 and 0.74, ICC = 0.80 and 0.77 respectively). However, Echo-AL had poor correlation and agreement with CMR-MSM (r = 0.66 and ICC = 0.48). Bland-Altman plots confirmed these findings. CMR-AL method may be used as an alternative to CMR-MSM, as it is non-invasive, rapid, and correlates well with CMR-MSM. LAV by different modalities should not be used interchangeably.


Asunto(s)
Fibrilación Atrial/diagnóstico , Ecocardiografía , Técnicas Electrofisiológicas Cardíacas , Atrios Cardíacos/diagnóstico por imagen , Atrios Cardíacos/patología , Imagen por Resonancia Cinemagnética , Imagen Multimodal/métodos , Potenciales de Acción , Anciano , Fibrilación Atrial/diagnóstico por imagen , Fibrilación Atrial/patología , Fibrilación Atrial/fisiopatología , Fibrilación Atrial/cirugía , Ablación por Catéter , Femenino , Atrios Cardíacos/fisiopatología , Atrios Cardíacos/cirugía , Humanos , Interpretación de Imagen Asistida por Computador , Imagenología Tridimensional , Masculino , Persona de Mediana Edad , Variaciones Dependientes del Observador , Valor Predictivo de las Pruebas , Reproducibilidad de los Resultados
15.
Am J Cardiol ; 114(1): 65-9, 2014 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-24819904

RESUMEN

It is unknown whether recurrence of atrial fibrillation (AF) is related to severity of left ventricular diastolic dysfunction (LVDD) before ablation in patients with preserved left ventricular ejection fraction (LVEF). We tested the hypothesis that the presence and/or severity of LVDD before catheter ablation are related to AF recurrence during the 12-month follow-up period in patients with normal LVEF. We also aimed to determine what echocardiographic and Doppler indexes of LVDD before ablation are associated with recurrence of AF after ablation. We identified 198 patients with normal LVEF who underwent catheter ablation for AF with evidence of normal sinus rhythm within 1 year before ablation. The recurrence rate during 12-month follow-up period was assessed. Of the 198 patients, 76 patients (38%) had symptomatic recurrence and 122 patients (62%) had no recurrence. None of the independent variables, including mitral valve Doppler E and A peak velocities, E/A ratio, tissue Doppler e' and a' peak velocities, left atrial volume index, isovolumic relaxation time, and deceleration time, predicted recurrence. Patients with average E/e' ratio >13, however, had increased recurrence (67% vs 35%, odds ratio 3.70, 95% confidence interval 1.21 to 11.3, p <0.05). In conclusion, there was no difference in the severity of LVDD using conventional echocardiographic indexes of LVDD in patients with or without recurrence of AF ablation. However, patients with average E/e' ratio >13 did have an increased recurrence rate of AF at 12 months after procedure. Therefore, E/e' ratio, indicative of increased left atrial pressure, may serve as a marker for AF recurrence after ablation.


Asunto(s)
Fibrilación Atrial/fisiopatología , Diástole/fisiología , Sístole/fisiología , Disfunción Ventricular Izquierda/fisiopatología , Antiarrítmicos/uso terapéutico , Fibrilación Atrial/diagnóstico por imagen , Fibrilación Atrial/terapia , Ablación por Catéter/métodos , Ecocardiografía Doppler , Femenino , Humanos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Recurrencia , Estudios Retrospectivos , Factores de Riesgo , Volumen Sistólico/fisiología , Tiempo de Tratamiento , Disfunción Ventricular Izquierda/diagnóstico por imagen , Disfunción Ventricular Izquierda/terapia
16.
J Stroke Cerebrovasc Dis ; 22(7): 959-61, 2013 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-22244712

RESUMEN

BACKGROUND: Previous research has revealed a higher prevalence of elevated cardiac troponin T or I levels amongst patients admitted with stroke, which has been associated with increased cardiovascular events, higher mortality rates, and poor inpatient prognosis. Because cardiac comorbidities account for almost 20% of deaths after ischemic stroke, it is important to understand the relationship between troponin elevation, cardiac events, and acute ischemic stroke (AIS). METHODS: We evaluated 137 consecutive patients ≥ 18 years of age who presented within 48 hours of AIS onset. All patients had laboratory markers drawn on admission, including troponin and brain natriuretic peptide, along with transthoracic echocardiogram with Doppler. The mean age of our study population was 71.7 ± 14.6 years. RESULTS: Twenty-four of 137 patients (17.5%) had a positive troponin level. Sixteen of 24 (67%) patients with a positive troponin level had a new wall motion abnormality on echocardiogram that was suggestive of unstable atherosclerotic disease. On statistical analysis, we found a significant association between troponin and brain natriuretic peptide elevation with positive segmental wall motion abnormality on echocardiogram. CONCLUSIONS: These study findings represent a new paradigm of interpreting elevated cardiac biomarkers and may help with risk stratification and diagnosis of patients presenting with AIS.


Asunto(s)
Isquemia Encefálica/sangre , Accidente Cerebrovascular/sangre , Troponina/sangre , Anciano , Anciano de 80 o más Años , Biomarcadores/sangre , Isquemia Encefálica/diagnóstico por imagen , Ecocardiografía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Péptido Natriurético Encefálico/sangre , Pronóstico , Accidente Cerebrovascular/diagnóstico por imagen
18.
J Occup Environ Hyg ; 6(12): 735-44, 2009 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19894174

RESUMEN

Beryllium exposure can cause a number of deleterious health effects, including beryllium sensitization and the potentially fatal chronic beryllium disease. Efficient methods for monitoring beryllium contamination in workplaces are valuable to help prevent dangerous exposures to this element. In this work, performance data on the extraction of beryllium from various size fractions of high-fired beryllium oxide (BeO) particles (from < 32 microm up to 212 microm) using dilute aqueous ammonium bifluoride (ABF) solution were obtained under various conditions. Beryllium concentrations were determined by fluorescence using a hydroxybenzoquinoline fluorophore. The effects of ABF concentration and volume, extraction temperature, sample tube types, and presence of filter or wipe media were examined. Three percent ABF extracts beryllium nearly twice as quickly as 1% ABF; extraction solution volume has minimal influence. Elevated temperatures increase the rate of extraction dramatically compared with room temperature extraction. Sample tubes with constricted tips yield poor extraction rates owing to the inability of the extraction medium to access the undissolved particles. The relative rates of extraction of Be from BeO of varying particle sizes were examined. Beryllium from BeO particles in fractions ranging from less than 32 microm up to 212 microm were subjected to various extraction schemes. The smallest BeO particles are extracted more quickly than the largest particles, although at 90 degrees C even the largest BeO particles reach nearly quantitative extraction within 4 hr in 3% ABF. Extraction from mixed cellulosic-ester filters, cellulosic surface-sampling filters, wetted cellulosic dust wipes, and cotton gloves yielded 90% or greater recoveries. Scanning electron microscopy of BeO particles, including partially dissolved particles, shows that dissolution in dilute ABF occurs not just on the exterior surface but also via accessing particles' interiors due to porosity of the BeO material. Comparison of dissolution kinetics data shows that as particle diameter approximately doubles, extraction time is increased by a factor of about 1.5, which is consistent with the influence of porosity on dissolution.


Asunto(s)
Berilio/química , Fraccionamiento Químico/métodos , Fluoruros/química , Compuestos de Amonio Cuaternario/química , Compuestos de Amonio , Berilio/aislamiento & purificación , Monitoreo del Ambiente , Cinética , Microscopía Electrónica de Rastreo , Tamaño de la Partícula , Espectrometría de Fluorescencia/métodos , Temperatura
19.
J Environ Monit ; 10(8): 955-60, 2008 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-18688465

RESUMEN

Analytical methods for the determination of trace beryllium in soils are needed so that anthropogenic sources of this element can be distinguished from native (background) levels of beryllium. In this work, a collaborative interlaboratory evaluation of a new extraction and fluorescence-based procedure for determining beryllium in soil samples was carried out to fulfil method validation requirements for ASTM International voluntary consensus standard test methods. A Canadian reference material, CCRMP Till-1 soil, with a background beryllium concentration of 2.4 microg g(-1), was selected for study. This certified reference material (CRM) was spiked and homogenized with varying levels of beryllium oxide in order to give batches of material with beryllium concentrations of 4.36 +/- 0.69, 11.5 +/- 0.7, 124 +/- 7 and 246 +/- 16 microg g(-1) (+/- values are standard deviations). In the interlaboratory study (ILS), which was carried out in accordance with an applicable ASTM International standard practice (ASTM E691), samples of these spiked soils were subjected to extraction in dilute ammonium bifluoride at approximately 90 degrees C for 40 h. Fluorescence measurement of the extracted beryllium was carried out via detection using the high quantum yield fluorophore, hydroxybenzoquinoline sulfonate (HBQS). Interlaboratory precision estimates from six participating laboratories ranged from 0.048 to 0.103 (relative standard deviations) for the five different beryllium concentrations. Pooled bias estimates resulting from this ILS were between -0.049 and 0.177 for the various beryllium levels. These figures of merit support promulgation of the analytical procedure as an ASTM International standard test method.


Asunto(s)
Berilio/química , Suelo/análisis , Monitoreo del Ambiente/métodos , Fluorescencia , Reproducibilidad de los Resultados , Contaminantes del Suelo/química
20.
Environ Sci Technol ; 42(6): 2066-71, 2008 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-18409638

RESUMEN

Beryllium metal and beryllium oxide are important industrial materials used in a variety of applications in the electronics, nuclear energy, and aerospace industries. These materials are highly toxic, they must be disposed of with care, and exposed workers need to be protected. Recently, a new analytical method was developed that uses dilute ammonium bifluoride for extraction of beryllium and a high quantum yield optical fluorescence reagent to determine trace amounts of beryllium in airborne and surface samples. The sample preparation and analysis procedure was published by both ASTM International and the National Institute for Occupational Safety and Health (NIOSH). The main advantages of this method are its sensitivity, simplicity, use of lower toxicity materials, and low capital costs. Use of the technique for analyzing soils has been initiated to help meet a need at several of the U.S. Department of Energy legacy sites. So far this work has mainly concentrated on developing a dissolution protocol for effectively extracting beryllium from a variety of soils and sediments so that these can be analyzed by optical fluorescence. Certified reference materials (CRM) of crushed rock and soils were analyzed for beryllium content using fluorescence, and results agree quantitatively with reference values.


Asunto(s)
Berilio/análisis , Contaminantes del Suelo/análisis , Monitoreo del Ambiente , Fluorescencia , Óptica y Fotónica
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