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1.
Mil Med ; 188(Suppl 6): 316-321, 2023 11 08.
Artigo em Inglês | MEDLINE | ID: mdl-37948262

RESUMO

INTRODUCTION: Point-of-Care Ultrasound (POCUS) is the utilization of bedside ultrasound by clinicians. Its portable and rapid diagnostic capabilities make it an excellent tool for deployment and mobile military settings. However, formal and uniform POCUS training is lacking. Furthermore, the evaluation of these curricula often relies on confidence assessment. Our objective was to assess the relationships between confidence, frequency of utilization, and image interpretation knowledge among our Internal Medicine residents before and after the implementation of a formal curriculum. MATERIALS AND METHODS: In November 2020, we implemented a longitudinal, flipped-classroom, academic half-day curriculum, conducting a prospective before-after cohort evaluation of its implementation. The POCUS curriculum was implemented as a longitudinal, asynchronous, flipped-classroom activity with workshop sessions during one academic half-day per month. We measured confidence via a Likert scale and utilization frequency via a five-point scale. Six multiple-choice questions (MCQ) with ultrasound videos assessed image interpretation competency. The image interpretation score was reported as percent correct. We related confidence and utilization to the image interpretation score. RESULTS: Ninety-nine residents were eligible for participation. Fifty-four (55%) completed a pre-curriculum assessment and 45 (45%) completed a post-curriculum assessment. Average image interpretation scores were 41% pre-curriculum and 51% post-curriculum (P =0.02). Pre-curriculum residents were on average unconfident (mean=2.56), and post-curriculum residents were on average confident (mean=3.62). Pre-curriculum residents used POCUS occasionally (mean=2.02, count 13 (24%) never utilizing). Post-curriculum residents used POCUS occasionally (mean=2.42, count 4 (9%) never utilizing). Pre- and post-curriculum confidence were not significantly associated with image interpretation scores (pre-curriculum: r=-0.10, P =0.50; post-curriculum: r=0.24, P =0.11). Pre- and post-curriculum utilization were not significantly associated with image interpretation scores (pre-curriculum: r=0.15, P =0.28; post-curriculum: r=0.02, P =0.90). The number of curriculum sessions attended was significantly associated with higher image interpretation scores (r=0.30, P =0.003). CONCLUSIONS: Our study suggests that POCUS confidence and informal utilization do not correlate with image interpretation knowledge on MCQs among Internal Medicine residents. These findings support assessing direct measures of knowledge, rather than confidence, as an endpoint in evaluating POCUS curricula among Internal Medicine residents.


Assuntos
Internato e Residência , Sistemas Automatizados de Assistência Junto ao Leito , Humanos , Estudos Prospectivos , Competência Clínica , Currículo , Ultrassonografia/métodos
2.
J Med Educ Curric Dev ; 10: 23821205231193284, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37547538

RESUMO

BACKGROUND: Point-of-care ultrasound (POCUS) has extensive clinical utility in internal medicine, but formal and uniform curricula in internal medicine are lacking. OBJECTIVE: To determine the effectiveness of a longitudinal, flipped-classroom, academic half-day curriculum on internal medicine resident confidence, utilization, and changes in clinical management. METHODS: We implemented an asynchronous, flipped-classroom, academic half-day curriculum from November 2020 to November 2021 and conducted an evaluation with a prospective, before-after cohort study. Curriculum included 4 rotating sessions comprised of 20 to 30 min of image interpretation followed by 1.5 to 2 h of image acquisition. Confidence was rated via Likert scale. Utilization was reported via indicating never, 1 to 2, 3 to 4, 5 to 6, or >6 times per month (recorded as 1-5, respectively). Image interpretation was assessed via a 6-question, multiple-choice video assessment. RESULTS: Nineteen of 99 potential residents (19%) completed a pre- and post-curriculum evaluation. Residents attended a median of 4 sessions. Confidence improved from 2.47 to 3.53 (P = .002). Utilization did not improve overall (2.11-2.42, P = .22), but utilization of left ventricular function assessment (1.53-2.00, P = .046) and pulmonary assessment (1.53-2.00, P = .039) increased. The percentage of residents that had ever changed their clinical management by POCUS increased from 47% to 84% after implementation of the curriculum. Cardiac, pulmonary/pleural, volume assessment, and abdominal free fluid exams were reported as the most clinically useful. CONCLUSION: Implementation of a longitudinal, academic half-day curriculum for POCUS resulted in improved confidence, increased POCUS utilization for the cardiac and pulmonary examination, and changes in clinical management based on POCUS.

3.
Mil Med ; 188(5-6): 928-931, 2023 05 16.
Artigo em Inglês | MEDLINE | ID: mdl-35762461

RESUMO

INTRODUCTION: Following the identification of coronavirus disease 2019 (COVID-19) in China, the virus has spread rapidly around the world causing severe illness and death. Several vaccines were found to be safe and effective and made available first to those most at risk and then to the general public. Despite the safety and efficacy profiles, vaccine hesitancy remains a significant barrier to widespread immunity. Within the military community at Wright-Patterson Air Force Base, we provided multiple physician-led educational seminars to address vaccination concerns and decrease vaccine hesitancy. MATERIALS AND METHODS: The authors presented a PowerPoint presentation of the available vaccinations, their safety data, and efficacy, followed by a town hall-style question-and-answer period where questions were presented from the previous submission, as well as real-time submissions through Facebook Live. The questions were fielded by specialists in Internal Medicine, Infectious Disease, Pulmonary-Critical Care, Obstetrics and Gynecology, and Rheumatology. The entire presentation was streamed through Facebook Live and was freely available. Following the presentation, an online survey was provided for willing participants to complete which included demographic data and addressed their previous and current attitudes toward COVID-19 vaccinations and their opinions on the presentation. Data from the survey were then analyzed through IBM SPSS Statistics 25.0 to find any associations or risk factors for hesitancy. RESULTS: There were 73 respondents to the assessment, most of which were nonmedical. Of the 73, the majority (45) had already received a vaccine for COVID-19. Of those unvaccinated, 17 did not want a vaccination before or after the seminar. Two did change their mind about being receptive to vaccination, and one changed from receptive to hesitant. The only statistically significant risk factors for vaccine hesitancy were those with a moderate to great amount of trust in their health care provider compared to those with little to no trust (73% vs. 4%, P < .001). CONCLUSIONS: Our intervention was limited in its effectiveness to address vaccine hesitancy late in the pandemic, with our study limited by our small sample size. Regardless, it identified a peculiar discrepancy with those with the most trust in health care providers being the most likely to be vaccine-hesitant. This highlights the importance of the information that trusted health care providers are providing to their patients and may identify more effective routes to address vaccine hesitancy in the future.


Assuntos
COVID-19 , Militares , Médicos , Feminino , Gravidez , Humanos , Vacinas contra COVID-19/uso terapêutico , Hesitação Vacinal , COVID-19/epidemiologia , COVID-19/prevenção & controle , Vacinação
4.
Am J Case Rep ; 23: e936441, 2022 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-35830369

RESUMO

BACKGROUND Pneumoscrotum is a rare clinical occurrence in which air accumulates in the scrotum. The origin of air is primarily from trauma, but spontaneous pneumoscrotum can develop from gastrointestinal or pulmonary sources. Physical examination of pneumoscrotum typically includes crepitus of the perineal region and scrotal swelling and associated findings depending on the origin of the free air. However, pneumoscrotum in the setting of a scrotal wound, which allows air to pass freely outside the body, has not been previously documented in the literature. CASE REPORT A 72-year-old man who recently underwent a scrotal incision and drainage for recurrent epididymitis presented to a local emergency room with chief concerns of "whistling scrotum" and dyspnea. The chest CT revealed bilateral pneumothoraces, pneumomediastinum, and excessive subcutaneous emphysema throughout his abdomen, perineum, and scrotum. His scrotum had a dehiscent wound without any gross edema or air trapping contained within the scrotum. He received bilateral chest tubes and subcutaneous air drains with complete resolution of his pneumothoraces. The pneumoscrotum and associated subcutaneous emphysema of the perineum and thighs resolved after a prolonged period, and necessitated additional scrotal surgery. CONCLUSIONS Prompt evaluation for source control is necessary with pneumoscrotum, as the source likely requires immediate stabilization or surgical intervention. This case report describes a unique presentation of a common entity (pneumothorax) within pulmonology/critical care in a patient with an open scrotal wound from a recent scrotal procedure, which allowed the air to escape from his abdominal compartment, and resulted in his "scrotal whistling." It is unclear how the air passing through the scrotum affected the patient's presentation, such as allowing more air to build up in the subcutaneous tissues versus developing critical illness.


Assuntos
Doenças dos Genitais Masculinos , Enfisema Mediastínico , Pneumotórax , Canto , Enfisema Subcutâneo , Idoso , Edema , Doenças dos Genitais Masculinos/complicações , Humanos , Masculino , Enfisema Mediastínico/complicações , Enfisema Mediastínico/etiologia , Pneumotórax/etiologia , Escroto , Enfisema Subcutâneo/etiologia
5.
Mil Med ; 187(11-12): e1255-e1260, 2022 10 29.
Artigo em Inglês | MEDLINE | ID: mdl-34117501

RESUMO

INTRODUCTION: Safe and effective vaccines against severe acute respiratory syndrome-associated coronavirus 2 are essential tools in the fight against the coronavirus disease 2019  (COVID-19) pandemic. However, hesitancy to vaccination is a major barrier to achieving herd immunity, particularly among a population working on a military base. To better understand the perceptions and concerns of these individuals, a voluntary survey was conducted. MATERIALS AND METHODS: An interactive, online survey was constructed and disseminated to individuals associated with Wright-Patterson Air Force Base (WPAFB) in Dayton, OH. Survey participation was voluntary with responses collected over the initial weeks in which WPAFB began to distribute COVID-19 vaccines in a series of phases. Although initially designed to collect demographic data and identify reasons for potential vaccine hesitancy among WPAFB 88th Medical Group personnel, the study population was expanded to include all WPAFB-affiliated personnel at the direction of base leadership. The chi-squared test was used to examine the relationships between categorical variables, while multivariable logistic regression was used to assess age and occupation as independent risk factors for vaccine hesitancy. RESULTS: A total of 816 individuals completed the survey, of whom 22.7% (n = 185) self-identified as vaccine hesitant (VH). The VH group had a lower mean age than the not vaccine hesitant (NVH) group (39.3 ± 14.2 vs. 45.9 ± 13.4, P < .001). Respondents whose occupation was medical were more likely to be VH than their non-medical colleagues (49% vs. 18%, P < .001). The VH group was more concerned about short-term side effects (43% vs. 26%, P < .001), long-term side effects (82% vs. 50%, P < 0.001), vaccine effectiveness (23% vs. 5%, P < .001), vaccine making them feel sick (22% vs. 13%, P = .002), being infected with COVID-19 from the vaccine (10% vs. 5%, P = 0.008), and worry about misinformation/political agenda (43% vs. 31%, P = 0.003). Younger respondents and medical personnel were more likely to be concerned about long-term side effects and vaccine effectiveness, and the younger group was also more likely to be concerned about pregnancy/breastfeeding issues and worry about misinformation/political agenda. Age (younger vs. older, odds ratio 2.15) and occupation (medical vs. non-medical, odds ratio 3.74) were independent risk factors for vaccine hesitancy. The NVH group was more likely to recommend the COVID-19 vaccine to a friend or family member than the VH group (93% vs. 20%, P < .001) as were the older age group (79% vs. 67%, P = .001) and non-medical personnel (81% vs. 52%, P < .001). CONCLUSIONS: Younger age and medical occupation were independent risk factors for vaccine hesitancy and these individuals were less likely to recommend vaccination to a friend or family member. We also identified several key concerns related to vaccination hesitancy, in particular those related to short- and long-term side effects, and the spread of misinformation. Among military personnel, these findings carry important implications that may negatively impact mission readiness, a matter that merits further investigation. Our COVID-19 vaccination hesitancy findings can be used to guide targeted interventions at future vaccination campaigns in a military population.


Assuntos
Vacinas contra COVID-19 , COVID-19 , Militares , Vacinação , Feminino , Humanos , Gravidez , COVID-19/epidemiologia , COVID-19/prevenção & controle , Vacinas contra COVID-19/efeitos adversos , Estudos Transversais , Conhecimentos, Atitudes e Prática em Saúde , Instalações Militares , Pais , Aceitação pelo Paciente de Cuidados de Saúde , SARS-CoV-2 , Vacinação/psicologia , Militares/psicologia , Comunicação , Adulto , Pessoa de Meia-Idade
6.
Mil Med ; 187(11-12): e1449-e1455, 2022 10 29.
Artigo em Inglês | MEDLINE | ID: mdl-34557913

RESUMO

BACKGROUND: Coronavirus disease 2019 (COVID-19) vaccine hesitancy is a major impediment to achieving herd immunity and overcoming the current pandemic. Our aim was to decrease the prevalence of vaccine hesitancy through an education intervention. METHOD: An education intervention, consisting of a PowerPoint presentation addressing the two mRNA COVID-19 vaccine concerns/myths and a question and answer panel comprising health care providers from various specialties, was implemented to address vaccine hesitancy among personnel associated with Wright-Patterson Air Force Base through a series of virtual and in-person seminars. Participants completed a post-seminar survey as a retrospective self-assessment to identify attitudes and views surrounding vaccine hesitancy and the impact of the education intervention. Chi-squared test was used to examine relationships between categorical variables, and multiple logistic regression was used to identify risk factors for vaccine hesitancy pre- and post-seminar. All analyses were done using SPSS Statistics Version 25.0 (IBM, Armonk, NY). Institutional Review Board approval was not obtained before this study as it began as a non-research initiative and received non-research determination post hoc. RESULTS: Five hundred participants completed the survey. Mean age was 44.7 years with 13.4 and 86.6% medical and non-medical personnel, respectively. Nearly all (98.8%) had not received their first shot of the vaccine series. 402 (80.9%) were receptive to vaccination, and 95 (19.1%) were hesitant post-seminar. Of the 139 participants who reported they were initially hesitant after our intervention, 50 (36%) indicated that they were now receptive to the vaccine, while 89 (64%) remained hesitant. Of those 50, 48 (96%) had moderate to great amount of trust in COVID-19 vaccine information presented by physicians/other providers. Six respondents who wanted the vaccine before the intervention no longer wanted the vaccine. A medical occupation (OR = 4.85, 95% CI = 2.63-8.96, P < .001), little or no trust in COVID-19 vaccine information from physicians/other providers (OR = 19.48, 95% CI = 7.31-51.90, P < 0.001), and being age 30 or younger (OR = 1.81, 95% CI = 1.02-3.2, P = 0.041) were independent predictors of vaccine hesitancy. Trust in providers was a significant factor in change of intent from vaccine hesitant to receptive post-intervention (OR 0.13, 95% CI = 0.03-0.59, P = .008). Age and occupation were not significant factors associated with change in intent. CONCLUSION: Our education intervention was effective in reducing COVID-19 vaccine hesitancy in a military base population. Study limitations include applications toward other military and non-military populations, the possibility of nonresponse bias, and absence of prior validated interventions. Area for future studies includes improvement upon educational intervention, development of other effective methods, and application of intervention in other populations.


Assuntos
COVID-19 , Vacinas , Humanos , Adulto , Vacinas contra COVID-19/uso terapêutico , Instalações Militares , Hesitação Vacinal , Estudos Retrospectivos , COVID-19/epidemiologia , COVID-19/prevenção & controle , Vacinação
7.
J Occup Environ Med ; 64(2): 146-150, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34456323

RESUMO

INTRODUCTION: Inhalational exposures are common among service members who deploy to southwest Asia. The objective of this study is to determine if deployed Air Force firefighters have any decline in spirometry related to deployment. METHODS: This study is a retrospective chart review. RESULTS: The database search identified 302 firefighters with documentation of two separate spirometry examinations. For deployed firefighters, mean change in forced expiratory volume at 1 second (FEV1) percent predicted was -1.01 ±â€Š7.86, forced vital capacity (FVC) was -0.46 ±â€Š10.26 predicted, and mid-expiratory flow (FEF25-75) was -0.13 ±â€Š12.97. For firefighters who had never deployed, mean change in FEV1 percent predicted was +0.08 ±â€Š7.09, FVC was +0.72 ±â€Š7.75, and FEF25-75 was -0.66 ±â€Š16.17. CONCLUSION: There does not appear to be evidence that deployment causes a significant change in lung function as measured by spirometry.


Assuntos
Bombeiros , Volume Expiratório Forçado , Humanos , Pulmão , Estudos Retrospectivos , Espirometria , Capacidade Vital
8.
Chest ; 160(1): e13-e17, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34246382

RESUMO

Light chain deposition disease is a rare condition that results in the deposition of light chains in organs and their subsequent dysfunction. It is often the consequence of unchecked light chain production by a plasma cell clone. Rarely does it manifest with solely pulmonary involvement, especially in the young otherwise healthy patient. This article highlights the presentation and diagnosis of pulmonary light chain deposition disease in an active duty solider, the discovery of a plasma cell clone responsible for his symptoms, and the therapy targeted at the plasma cell clone-inducing pulmonary disease. This therapy included a novel successful treatment with an autologous stem cell transplantation. To date, it is among the first such documented successful bone marrow transplantations in treatment of isolated pulmonary light chain deposition disease.


Assuntos
Pneumopatias/terapia , Paraproteinemias/terapia , Transplante de Células-Tronco/métodos , Adulto , Biópsia , Humanos , Pneumopatias/diagnóstico , Pneumopatias/etiologia , Masculino , Paraproteinemias/complicações , Paraproteinemias/diagnóstico , Tomografia Computadorizada por Raios X , Transplante Autólogo
9.
Chest ; 158(4): e181-e185, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-33036116

RESUMO

CASE PRESENTATION: A 21-year-old male African American college student from Southern California, with no significant medical history, was visiting family in southwestern Texas when he presented to the hospital with 1 week history of cough, shortness of breath, lower back pain, and a 10-pound weight loss.


Assuntos
Coccidioidomicose/diagnóstico , Síndrome do Desconforto Respiratório/diagnóstico , Coccidioidomicose/complicações , Tosse/etiologia , Humanos , Masculino , Síndrome do Desconforto Respiratório/complicações , Síndrome do Desconforto Respiratório/microbiologia , Adulto Jovem
10.
J Gen Virol ; 95(Pt 4): 836-848, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24394697

RESUMO

From 1 January 2009 to 31 May 2013, 15 287 respiratory specimens submitted to the Clinical Virology Laboratory at the Children's Hospital Colorado were tested for human coronavirus RNA by reverse transcription-PCR. Human coronaviruses HKU1, OC43, 229E and NL63 co-circulated during each of the respiratory seasons but with significant year-to-year variability, and cumulatively accounted for 7.4-15.6 % of all samples tested during the months of peak activity. A total of 79 (0.5 % prevalence) specimens were positive for human betacoronavirus HKU1 RNA. Genotypes HKU1 A and B were both isolated from clinical specimens and propagated on primary human tracheal-bronchial epithelial cells cultured at the air-liquid interface and were neutralized in vitro by human intravenous immunoglobulin and by polyclonal rabbit antibodies to the spike glycoprotein of HKU1. Phylogenetic analysis of the deduced amino acid sequences of seven full-length genomes of Colorado HKU1 viruses and the spike glycoproteins from four additional HKU1 viruses from Colorado and three from Brazil demonstrated remarkable conservation of these sequences with genotypes circulating in Hong Kong and France. Within genotype A, all but one of the Colorado HKU1 sequences formed a unique subclade defined by three amino acid substitutions (W197F, F613Y and S752F) in the spike glycoprotein and exhibited a unique signature in the acidic tandem repeat in the N-terminal region of the nsp3 subdomain. Elucidating the function of and mechanisms responsible for the formation of these varying tandem repeats will increase our understanding of the replication process and pathogenicity of HKU1 and potentially of other coronaviruses.


Assuntos
Infecções por Coronaviridae/epidemiologia , Infecções por Coronaviridae/virologia , Coronaviridae/classificação , Coronaviridae/isolamento & purificação , Infecções Respiratórias/epidemiologia , Infecções Respiratórias/virologia , Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , Células Cultivadas , Análise por Conglomerados , Colorado , Coronaviridae/genética , Genótipo , Humanos , Dados de Sequência Molecular , Filogenia , RNA Viral/genética , Análise de Sequência de DNA , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/imunologia , Cultura de Vírus
11.
Am J Respir Cell Mol Biol ; 48(6): 742-8, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23418343

RESUMO

Severe acute respiratory syndrome (SARS)-coronavirus (CoV) produces a devastating primary viral pneumonia with diffuse alveolar damage and a marked increase in circulating cytokines. One of the major cell types to be infected is the alveolar type II cell. However, the innate immune response of primary human alveolar epithelial cells infected with SARS-CoV has not been defined. Our objectives included developing a culture system permissive for SARS-CoV infection in primary human type II cells and defining their innate immune response. Culturing primary human alveolar type II cells at an air-liquid interface (A/L) improved their differentiation and greatly increased their susceptibility to infection, allowing us to define their primary interferon and chemokine responses. Viral antigens were detected in the cytoplasm of infected type II cells, electron micrographs demonstrated secretory vesicles filled with virions, virus RNA concentrations increased with time, and infectious virions were released by exocytosis from the apical surface of polarized type II cells. A marked increase was evident in the mRNA concentrations of interferon-ß and interferon-λ (IL-29) and in a large number of proinflammatory cytokines and chemokines. A surprising finding involved the variability of expression of angiotensin-converting enzyme-2, the SARS-CoV receptor, in type II cells from different donors. In conclusion, the cultivation of alveolar type II cells at an air-liquid interface provides primary cultures in which to study the pulmonary innate immune responses to infection with SARS-CoV, and to explore possible therapeutic approaches to modulating these innate immune responses.


Assuntos
Células Epiteliais/imunologia , Imunidade Inata , Síndrome Respiratória Aguda Grave/imunologia , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/imunologia , Enzima de Conversão de Angiotensina 2 , Antígenos Virais/imunologia , Antígenos Virais/metabolismo , Diferenciação Celular , Citoplasma/imunologia , Citoplasma/ultraestrutura , Citoplasma/virologia , Células Epiteliais/virologia , Humanos , Interferon beta/imunologia , Interferon beta/metabolismo , Interferons , Interleucinas/imunologia , Interleucinas/metabolismo , Peptidil Dipeptidase A/imunologia , Peptidil Dipeptidase A/metabolismo , Cultura Primária de Células , Alvéolos Pulmonares/citologia , Alvéolos Pulmonares/imunologia , Alvéolos Pulmonares/virologia , RNA Mensageiro/metabolismo , Receptores Virais/metabolismo , Mucosa Respiratória/citologia , Mucosa Respiratória/imunologia , Mucosa Respiratória/virologia , Fatores de Tempo , Liberação de Vírus
12.
Chem Commun (Camb) ; 49(9): 907-9, 2013 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-23247801

RESUMO

The binding process of quantum dots and DNA origami was monitored using a 3D, real-time, single-particle tracking system. Single-molecule binding events were directly observed and precise measurements of the diffusion coefficient and second-order photon correlation function, g(2)(τ), were combined to distinguish free quantum dots from different conjugates of nQdot-origami.


Assuntos
DNA/química , Pontos Quânticos , Sítios de Ligação , Difusão , Conformação de Ácido Nucleico
13.
ACS Nano ; 6(11): 9496-502, 2012 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-23102414

RESUMO

We demonstrate a method using photoactivation localization microscopy (PALM) in a soft-material system, with a rhodamine-lactam dye that is activated by both ultraviolet light and protonation, to reveal the nanoscale photoacid distribution in a model photoresist. Chemically amplified resists are the principal lithographic materials used in the semiconductor industry. The photoacid distribution generated upon exposure and its subsequent evolution during post-exposure bake is a major limiting factor in determining the resolution and lithographic quality of the final developed resist image. Our PALM data sets resolve the acid distribution in a latent image with subdiffraction limit accuracy. Our overall accuracy is currently limited by residual mechanical drift.


Assuntos
Ácidos/análise , Aumento da Imagem/métodos , Teste de Materiais/métodos , Microscopia de Fluorescência/métodos , Imagem Molecular/métodos , Nanoestruturas/ultraestrutura , Fotografação/métodos
14.
Phys Rev E Stat Nonlin Soft Matter Phys ; 85(6 Pt 1): 061916, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23005136

RESUMO

Single-particle tracking is increasingly used to extract quantitative parameters on single molecules and their environment, while advances in spatial and temporal resolution of tracking techniques inspire new questions and avenues of investigation. Correspondingly, sophisticated analytical methods are constantly developed to obtain more refined information from measured trajectories. Here we point out some fundamental limitations of these approaches due to the finite length of trajectories, the presence of localization error, and motion blur, focusing on the simplest motion regime of free diffusion in an isotropic medium (Brownian motion). We show that two recently proposed algorithms approach the theoretical limit of diffusion coefficient uncertainty. We discuss the practical performance of the algorithms as well as some important implications of these results for single-particle tracking.


Assuntos
Algoritmos , Biopolímeros/análise , Imagem Molecular/métodos , Reconhecimento Automatizado de Padrão/métodos
15.
Langmuir ; 28(25): 9181-8, 2012 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-22667449

RESUMO

Single-particle tracking with real-time feedback control can be used to study three-dimensional nanoparticle transport dynamics. We apply the method to study the behavior of adsorbed nanoparticles at a silicone oil-water interface in a microemulsion system over a range of particles sizes from 24 nm to 2000 nm. The diffusion coefficient of large particles (>200 nm) scales inversely with particle size, while smaller particles exhibit an unexpected increase in drag force at the interface. The technique can be applied in the future to study three-dimensional dynamics in a range of systems, including complex fluids, gels, biological cells, and geological media.


Assuntos
Nanopartículas/química , Óleos/química , Água/química , Difusão , Emulsões , Corantes Fluorescentes/química , Movimento (Física) , Poliestirenos/química , Fatores de Tempo
16.
PLoS One ; 6(5): e19156, 2011 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-21589915

RESUMO

Bats are reservoirs for many different coronaviruses (CoVs) as well as many other important zoonotic viruses. We sampled feces and/or anal swabs of 1,044 insectivorous bats of 2 families and 17 species from 21 different locations within Colorado from 2007 to 2009. We detected alphacoronavirus RNA in bats of 4 species: big brown bats (Eptesicus fuscus), 10% prevalence; long-legged bats (Myotis volans), 8% prevalence; little brown bats (Myotis lucifugus), 3% prevalence; and western long-eared bats (Myotis evotis), 2% prevalence. Overall, juvenile bats were twice as likely to be positive for CoV RNA as adult bats. At two of the rural sampling sites, CoV RNAs were detected in big brown and long-legged bats during the three sequential summers of this study. CoV RNA was detected in big brown bats in all five of the urban maternity roosts sampled throughout each of the periods tested. Individually tagged big brown bats that were positive for CoV RNA and later sampled again all became CoV RNA negative. Nucleotide sequences in the RdRp gene fell into 3 main clusters, all distinct from those of Old World bats. Similar nucleotide sequences were found in amplicons from gene 1b and the spike gene in both a big-brown and a long-legged bat, indicating that a CoV may be capable of infecting bats of different genera. These data suggest that ongoing evolution of CoVs in bats creates the possibility of a continued threat for emergence into hosts of other species. Alphacoronavirus RNA was detected at a high prevalence in big brown bats in roosts in close proximity to human habitations (10%) and known to have direct contact with people (19%), suggesting that significant potential opportunities exist for cross-species transmission of these viruses. Further CoV surveillance studies in bats throughout the Americas are warranted.


Assuntos
Quirópteros/virologia , Coronaviridae/isolamento & purificação , Animais , Coronaviridae/classificação , Coronaviridae/genética , Humanos , Filogenia , Reação em Cadeia da Polimerase Via Transcriptase Reversa
17.
Phys Rev E Stat Nonlin Soft Matter Phys ; 82(1 Pt 1): 011917, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20866658

RESUMO

Camera-based single-particle tracking enables quantitative determination of transport properties and provides nanoscale information about material characteristics such as viscosity and elasticity. However, static localization noise and the blurring of a particle's position over camera integration times introduce artifacts into measurement results even for a particle executing simple diffusion. Common data analysis methods based on the mean-square displacement do not properly account for these effects. In this paper, we analyze the statistics of tracking data for freely diffusing particles in realistic experimental scenarios. We derive a convenient and asymptotically optimal maximum likelihood estimator for the diffusion coefficient and for the magnitude of localization noise together with the corresponding Fisher information, which bounds the performance of all unbiased estimators. We find that the effect of varying the illumination profile during the camera integration time is quantified by a motion blur coefficient, R . We also find that a double-pulse illumination sequence maximizes the information content in some common experimental scenarios. Our results provide a rigorous theoretical framework and practical experimental recipe for achieving optimal performance in camera-based single-particle tracking.


Assuntos
Biopolímeros/análise , Rastreamento de Células/métodos , Interpretação de Imagem Assistida por Computador/métodos , Microscopia/métodos , Fotografação/métodos , Interpretação Estatística de Dados , Tamanho da Partícula
18.
Opt Lett ; 35(11): 1905-7, 2010 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-20517457

RESUMO

Several recently developed particle-tracking and imaging methods have achieved three-dimensional sensitivity through the introduction of angled micromirrors into the observation volume of an optical microscope. We model the imaging response of such devices and show how the direct and reflected images of a fluorescent particle are affected. In particle-tracking applications, asymmetric image degradation manifests itself as systematic tracking errors. Based on our results, we identify strategies for reducing systematic errors to the 10nm level in practical applications.


Assuntos
Biopolímeros/análise , Imageamento Tridimensional/métodos , Lentes , Microscopia/instrumentação , Modelos Teóricos , Simulação por Computador , Desenho de Equipamento , Análise de Falha de Equipamento , Tamanho da Partícula , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
19.
Nano Lett ; 10(7): 2525-30, 2010 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-20509676

RESUMO

We present a method for manipulating preselected quantum dots (QDs) with nanometer precision by flow control. The accuracy of this approach scales more favorably with particle size than optical trapping, enabling more precise positioning of nanoscopic particles. We demonstrate the ability to position a single QD in a 100 microm working region to 45 nm accuracy for holding times exceeding one hour and the ability to take active quantum measurements on the dynamically manipulated QD.

20.
ACS Nano ; 3(3): 609-14, 2009 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-19309171

RESUMO

We demonstrate high-resolution, high-speed 3D nanoparticle tracking using angled micromirrors. When angled micromirrors are introduced into the field of view of an optical microscope, reflected side-on views of a diffusing nanoparticle are projected alongside the usual direct image. The experimental design allows us to find the 3D particle trajectory using fast, centroid-based image processing, with no nonlinear computing operations. We have tracked polystyrene particles of 190 nm diameter with position measurement precision <20 nm in 3D with 3 ms frame duration (i.e., at an imaging rate >330 frames per second). Because the image processing requires only approximately 1 ms per frame, this technique could enable real-time feedback-controlled nanoparticle assembly applications with nanometer precision.

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