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1.
Comput Educ ; 211: 104985, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38562432

RESUMO

This study examined middle school students' perceptions of an automated writing evaluation (AWE) system, MI Write. We summarize students' perceptions of MI Write's usability, usefulness, and desirability both quantitatively and qualitatively. We then estimate hierarchical entry regression models that account for district context, classroom climate, demographic factors (i.e., gender, special education status, limited English proficiency status, socioeconomic status, grade), students' writing-related beliefs and affect, and students' writing proficiency as predictors of students' perceptions. Controlling for districts, students reporting more optimal classroom climate also reported higher usability, usefulness, and desirability for MI Write. Also, model results revealed that eighth graders, students with limited English proficiency, and students of lower socioeconomic status perceived MI Write relatively more useable; students with lower socioeconomic status also perceived MI Write relatively more useful and desirable. Students who liked writing more and more strongly believed that writing is a recursive process viewed MI Write as more useable, useful, and desirable. Students with greater writing proficiency viewed MI Write as less useable and useful; writing proficiency was not related to desirability perceptions. We conclude with a discussion of implications and future directions.

3.
Nat Methods ; 17(3): 261-272, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32015543

RESUMO

SciPy is an open-source scientific computing library for the Python programming language. Since its initial release in 2001, SciPy has become a de facto standard for leveraging scientific algorithms in Python, with over 600 unique code contributors, thousands of dependent packages, over 100,000 dependent repositories and millions of downloads per year. In this work, we provide an overview of the capabilities and development practices of SciPy 1.0 and highlight some recent technical developments.


Assuntos
Algoritmos , Biologia Computacional/métodos , Linguagens de Programação , Software , Biologia Computacional/história , Simulação por Computador , História do Século XX , História do Século XXI , Modelos Lineares , Modelos Biológicos , Dinâmica não Linear , Processamento de Sinais Assistido por Computador
4.
Eur Radiol ; 33(10): 7056-7065, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37083742

RESUMO

OBJECTIVES: Evaluate a novel algorithm for noise reduction in obese patients using dual-source dual-energy (DE) CT imaging. METHODS: Seventy-nine patients with contrast-enhanced abdominal imaging (54 women; age: 58 ± 14 years; BMI: 39 ± 5 kg/m2, range: 35-62 kg/m2) from seven DECT (SOMATOM Flash or Force) were retrospectively included (01/2019-12/2020). Image domain data were reconstructed with the standard clinical algorithm (ADMIRE/SAFIRE 2), and denoised with a comparison (ME-NLM) and a test algorithm (rank-sparse kernel regression). Contrast-to-noise ratio (CNR) was calculated. Four blinded readers evaluated the same original and denoised images (0 (worst)-100 (best)) in randomized order for perceived image noise, quality, and their comfort making a diagnosis from a table of 80 options. Comparisons between algorithms were performed using paired t-tests and mixed-effects linear modeling. RESULTS: Average CNR was 5.0 ± 1.9 (original), 31.1 ± 10.3 (comparison; p < 0.001), and 8.9 ± 2.9 (test; p < 0.001). Readers were in good to moderate agreement over perceived image noise (ICC: 0.83), image quality (ICC: 0.71), and diagnostic comfort (ICC: 0.6). Diagnostic accuracy was low across algorithms (accuracy: 66, 63, and 67% (original, comparison, test)). The noise received a mean score of 54, 84, and 66 (p < 0.05); image quality 59, 61, and 65; and the diagnostic comfort 63, 68, and 68, respectively. Quality and comfort scores were not statistically significantly different between algorithms. CONCLUSIONS: The test algorithm produces quantitatively higher image quality than current standard and existing denoising algorithms in obese patients imaged with DECT and readers show a preference for it. CLINICAL RELEVANCE STATEMENT: Accurate diagnosis on CT imaging of obese patients is challenging and denoising algorithms can increase the diagnostic comfort and quantitative image quality. This could lead to better clinical reads. KEY POINTS: • Improving image quality in DECT imaging of obese patients is important for accurate and confident clinical reads, which may be aided by novel denoising algorithms using image domain data. • Accurate diagnosis on CT imaging of obese patients is especially challenging and denoising algorithms can increase quantitative and qualitative image quality. • Image domain algorithms can generalize well and can be implemented at other institutions.


Assuntos
Algoritmos , Tomografia Computadorizada por Raios X , Humanos , Feminino , Adulto , Pessoa de Meia-Idade , Idoso , Tomografia Computadorizada por Raios X/métodos , Estudos Retrospectivos , Imagens de Fantasmas , Obesidade/complicações , Obesidade/diagnóstico por imagem , Doses de Radiação , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Razão Sinal-Ruído
5.
J Appl Clin Med Phys ; 24(11): e14164, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37787494

RESUMO

The American Association of Physicists in Medicine began the Medical Physics Leadership Academy Journal Club in the fall of 2020. The initiative was launched to provide a forum for medical physicists to learn about leadership topics using published material, discuss and reflect on the material, and consider incorporating the discussed skills into their professional practice. This report presents the framework for the MPLA Journal Club program, describes the lessons learned over the last 2 years, summarizes the data collected from attendees, and highlights the roadmap for the program moving forward.


Assuntos
Liderança , Física , Humanos , Estados Unidos
6.
J Phys Chem A ; 126(26): 4255-4263, 2022 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-35737724

RESUMO

The interplay between the solvent polarity and ionic atmosphere in anion-π association was evaluated via an experimental and a computational study of the BQ·X- complexes between benzoquinones (BQ) and halide anions (X-). The UV-Vis spectral measurements showed that these complexes are characterized by the strong absorption bands in the 300-450 nm range and their effective formation constants, Keff, measured in dichloromethane in the absence (or at low concentrations) of the supporting electrolyte, Bu4NPF6, were higher than those in acetonitrile. The experimental data were consistent with the results of the computations, which showed that magnitudes of the interaction energy, ΔE, between BQ and X- decreased considerably with the increase in the polarity of the media. The addition of auxiliary electrolytes (e.g., Bu4NPF6) led to a decrease in the concentration of the BQ·X- complexes. These changes were related to the competing associations of the π-acceptors with halides and PF6- anions (since the interaction energies between BQ acceptors and common non-halide anions, e.g., PF6-, BF4-, and NO3-, were comparable to those in the BQ·X- complexes) and to the increased ionic strength of the solutions. The variations in strength of anion-π interactions with the solvent polarity and ionic atmosphere were related to the higher effective ionic radii of the complexes. Due to the larger effects of the auxiliary electrolytes in dichloromethane, the formation constants for the BQ·X- complexes measured at high ionic strength in this solvent were lower than those in more polar acetonitrile or propylene carbonate. Such a combination of the effects of the solvent and ionic atmosphere should be taken into account when comparing experimental data with the results of the calculations and in design of the systems for molecular recognition and catalysis.

7.
Proc Natl Acad Sci U S A ; 116(11): 4843-4848, 2019 03 12.
Artigo em Inglês | MEDLINE | ID: mdl-30804190

RESUMO

Despite being a fundamental electronic component for over 70 years, it is still possible to develop different transistor designs, including the addition of a diode-like Schottky source electrode to thin-film transistors. The discovery of a dependence of the source barrier height on the semiconductor thickness and derivation of an analytical theory allow us to propose a design rule to achieve extremely high voltage gain, one of the most important figures of merit for a transistor. Using an oxide semiconductor, an intrinsic gain of 29,000 was obtained, which is orders of magnitude higher than a conventional Si transistor. These same devices demonstrate almost total immunity to negative bias illumination temperature stress, the foremost bottleneck to using oxide semiconductors in major applications, such as display drivers. Furthermore, devices fabricated with channel lengths down to 360 nm display no obvious short-channel effects, another critical factor for high-density integrated circuits and display applications. Finally, although the channel material of conventional transistors must be a semiconductor, by demonstrating a high-performance transistor with a semimetal-like indium tin oxide channel, the range and versatility of materials have been significantly broadened.

8.
AJR Am J Roentgenol ; 216(3): 824-834, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33474986

RESUMO

OBJECTIVE. The purpose of this study is to comprehensively implement a patient-informed organ dose monitoring framework for clinical CT and compare the effective dose (ED) according to the patient-informed organ dose with ED according to the dose-length product (DLP) in 1048 patients. MATERIALS AND METHODS. Organ doses for a given examination are computed by matching the topogram to a computational phantom from a library of anthropomorphic phantoms and scaling the fixed tube current dose coefficients by the examination volume CT dose index (CTDIvol) and the tube-current modulation using a previously validated convolution-based technique. In this study, the library was expanded to 58 adult, 56 pediatric, five pregnant, and 12 International Commission on Radiological Protection (ICRP) reference models, and the technique was extended to include multiple protocols, a bias correction, and uncertainty estimates. The method was implemented in a clinical monitoring system to estimate organ dose and organ dose-based ED for 647 abdomen-pelvis and 401 chest examinations, which were compared with DLP-based ED using a t test. RESULTS. For the majority of the organs, the maximum errors in organ dose estimation were 18% and 8%, averaged across all protocols, without and with bias correction, respectively. For the patient examinations, DLP-based ED was significantly different from organ dose-based ED by as much as 190.9% and 234.7% for chest and abdomen-pelvis scans, respectively (mean, 9.0% and 24.3%). The differences were statistically significant (p < .001) and exhibited overestimation for larger-sized patients and underestimation for smaller-sized patients. CONCLUSION. A patient-informed organ dose estimation framework was comprehensively implemented applicable to clinical imaging of adult, pediatric, and pregnant patients. Compared with organ dose-based ED, DLP-based ED may overestimate effective dose for larger-sized patients and underestimate it for smaller-sized patients.


Assuntos
Doses de Radiação , Monitoramento de Radiação/métodos , Tomografia Computadorizada por Raios X , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Pontos de Referência Anatômicos/diagnóstico por imagem , Tamanho Corporal , Osso e Ossos/diagnóstico por imagem , Criança , Feminino , Idade Gestacional , Humanos , Fígado/diagnóstico por imagem , Pulmão/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Pelve/diagnóstico por imagem , Imagens de Fantasmas , Gravidez , Padrões de Referência , Estudos Retrospectivos , Fluxo de Trabalho , Adulto Jovem
9.
CNS Spectr ; 26(3): 202-221, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-32054558

RESUMO

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder that manifests in childhood and can persist into adolescence and adulthood. Impairments associated with ADHD can impact quality of life, social interactions, and increase the risk of morbidity and mortality; however, for many patients, effective treatment can lessen these effects. Pharmacotherapy with stimulants or nonstimulants is recommended in conjunction with psychosocial therapy for most patients. Determining the optimal pharmacotherapy can be complex, and the clinician needs to consider many factors such as the patient's age, comorbidities, and lifestyle. Furthermore, the needs of the patient with ADHD will change over time, with specific challenges to consider at each stage of life. A variety of Food and Drug Administration (FDA)-approved stimulant and nonstimulant formulations are available with different modes of delivery and durations of effect. This armamentarium of ADHD medications can be used to individualize ADHD treatment for each patient's needs. This article combines current information from the literature and the first-hand experience of the authors to provide guidance on ADHD treatment options for patients of different ages and for some of the more common comorbidities.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/tratamento farmacológico , Estimulantes do Sistema Nervoso Central/administração & dosagem , Adolescente , Fatores Etários , Transtorno do Deficit de Atenção com Hiperatividade/complicações , Transtorno do Deficit de Atenção com Hiperatividade/epidemiologia , Transtorno Autístico/epidemiologia , Estimulantes do Sistema Nervoso Central/efeitos adversos , Estimulantes do Sistema Nervoso Central/uso terapêutico , Criança , Comorbidade , Depressão/epidemiologia , Cálculos da Dosagem de Medicamento , Humanos , Adulto Jovem
10.
J Shoulder Elbow Surg ; 29(3): 491-496, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31519425

RESUMO

HYPOTHESIS: The purpose of this study was to evaluate the association between smoking and postoperative complications following total shoulder arthroplasty. We hypothesized that active smokers would have significantly greater postoperative medical and surgical complications. METHODS: The American College of Surgeons National Surgical Quality Improvement Program database was queried for patients who underwent total shoulder arthroplasties from 2005 through 2016. Patients were stratified based on tobacco use within the past year. Logistic regression was used to assess the relationship between smoking status and postoperative medical and surgical complications. Multivariate logistic regression was used to adjust for demographic and comorbid factors. RESULTS: We identified 14,465 patients, of whom 10.5% were active smokers. Smokers were more likely to be younger, to be female patients, and to have a lower body mass index compared with nonsmokers (P < .001). Univariate analysis demonstrated that smoking was not associated with postoperative medical complications (P > .05) but was associated with an increased risk of overall surgical complications (odds ratio [OR], 3.259; 95% confidence interval [CI], 1.861-5.709; P < .001). Multivariate modeling showed that smoking increased the risk of wound complications (adjusted OR, 7.564; 95% CI, 2.128-26.889; P = .002) and surgical-site infections (adjusted OR, 1.927; 95% CI, 1.023-3.630; P = .042). DISCUSSION AND CONCLUSION: This study demonstrates that smoking is associated with an increased risk of surgical complications following total shoulder arthroplasty. On the basis of our available data, medical complications are not significantly increased. This information can help risk stratify patients prior to their procedures.


Assuntos
Artroplastia do Ombro/efeitos adversos , Fumar/efeitos adversos , Deiscência da Ferida Operatória/epidemiologia , Infecção da Ferida Cirúrgica/epidemiologia , Idoso , Estudos de Coortes , Bases de Dados Factuais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Estudos Retrospectivos , Estados Unidos/epidemiologia
11.
Phys Rev Lett ; 122(1): 013402, 2019 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-31012724

RESUMO

We study the loss of atoms in quantum Newton's cradles with a range of average energies and transverse confinements. We find that the three-body collision rate in one-dimension is strongly energy dependent, as predicted by a strictly 1D theory. We adapt the theory to atoms in waveguides, then, using detailed momentum measurements to infer all the collisions that occur, we compare the observed loss to the adapted theory and find that they agree well.

12.
AJR Am J Roentgenol ; 213(4): 889-894, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31180737

RESUMO

OBJECTIVE. Diagnostic reference levels were developed as guidance for radiation dose in medical imaging and, by inference, diagnostic quality. The objective of this work was to expand the concept of diagnostic reference levels to explicitly include noise of CT examinations to simultaneously target both dose and quality through corresponding reference values. MATERIALS AND METHODS. The study consisted of 2851 adult CT examinations performed with scanners from two manufacturers and two clinical protocols: abdominopelvic CT with IV contrast administration and chest CT without IV contrast administration. An institutional informatics system was used to automatically extract protocol type, patient diameter, volume CT dose index, and noise magnitude from images. The data were divided into five reference patient size ranges. Noise reference level, noise reference range, dose reference level, and dose reference range were defined for each size range. RESULTS. The data exhibited strong dependence between dose and patient size, weak dependence between noise and patient size, and different trends for different manufacturers with differing strategies for tube current modulation. The results suggest size-based reference intervals and levels for noise and dose (e.g., noise reference level and noise reference range of 11.5-12.9 HU and 11.0-14.0 HU for chest CT and 10.1-12.1 HU and 9.4-13.7 HU for abdominopelvic CT examinations) that can be targeted to improve clinical performance consistency. CONCLUSION. New reference levels and ranges, which simultaneously consider image noise and radiation dose information across wide patient populations, were defined and determined for two clinical protocols. The methods of new quantitative constraints may provide unique and useful information about the goal of managing the variability of image quality and dose in clinical CT examinations.


Assuntos
Ruído , Doses de Radiação , Tomografia Computadorizada por Raios X/normas , Adulto , Tamanho Corporal , Meios de Contraste , Humanos , Radiografia Abdominal/normas , Radiografia Torácica/normas , Valores de Referência
13.
Traffic ; 17(9): 1027-41, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27288050

RESUMO

Stimulated exocytic events provide a means for physiological communication and are a hallmark of the mast cell-mediated allergic response. In mast cells these processes are triggered by antigen crosslinking of IgE bound to its high-affinity receptor, FcϵRI, on the cell surface. Here we use the endosomal v-SNARE VAMP8, and the lysosomal hydrolase ß-hexosaminidase (ß-Hex), each C-terminally fused to super-ecliptic pHluorin, to monitor stimulated exocytosis. Using these pHluorin-tagged constructs, we monitor stimulated exocytosis by fluorimetry and visualize individual exocytic events with total internal reflection (TIRF) microscopy. Similar to constitutive recycling endosome (RE) trafficking, we find that stimulated RE exocytosis, monitored by VAMP8, is attenuated by expression of dominant negative (S25N) Rab11. Stimulated ß-Hex exocytosis is also reduced in the presence of S25N Rab11, suggesting that expression of this mutant broadly impacts exocytosis. Interestingly, pretreatment with inhibitors of actin polymerization, cytochalasin D or latrunculin A, substantially restores both RE and lysosome exocytosis in cells expressing S25N Rab11. Conversely, stabilizing F-actin with jasplakinolide inhibits antigen-stimulated exocytosis but is not additive with S25N Rab11-mediated inhibition, suggesting that these reagents inhibit related processes. Together, our results suggest that Rab11 participates in the regulation necessary for depolymerization of the actin cytoskeleton during stimulated exocytosis in mast cells.


Assuntos
Endossomos/metabolismo , Exocitose/fisiologia , Mastócitos/metabolismo , Proteínas rab de Ligação ao GTP/metabolismo , Animais , Degranulação Celular , Linhagem Celular Tumoral , Membrana Celular/metabolismo , Membrana Celular/ultraestrutura , Endossomos/ultraestrutura , Exocitose/imunologia , Fluorometria , Humanos , Mastócitos/efeitos dos fármacos , Mastócitos/imunologia , Microscopia de Fluorescência , Transporte Proteico , Ratos , Vesículas Transportadoras/metabolismo , Vesículas Transportadoras/ultraestrutura , Proteínas rab de Ligação ao GTP/genética
14.
Traffic ; 17(3): 191-210, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26650540

RESUMO

Coat protein complex II (COPII) vesicle formation at the endoplasmic reticulum (ER) transports nascent secretory proteins forward to the Golgi complex. To further define the machinery that packages secretory cargo and targets vesicles to Golgi membranes, we performed a comprehensive proteomic analysis of purified COPII vesicles. In addition to previously known proteins, we identified new vesicle proteins including Coy1, Sly41 and Ssp120, which were efficiently packaged into COPII vesicles for trafficking between the ER and Golgi compartments. Further characterization of the putative calcium-binding Ssp120 protein revealed a tight association with Emp47 and in emp47Δ cells Ssp120 was mislocalized and secreted. Genetic analyses demonstrated that EMP47 and SSP120 display identical synthetic positive interactions with IRE1 and synthetic negative interactions with genes involved in cell wall assembly. Our findings support a model in which the Emp47-Ssp120 complex functions in transport of plasma membrane glycoproteins through the early secretory pathway.


Assuntos
Vesículas Revestidas pelo Complexo de Proteína do Envoltório/metabolismo , Glicoproteínas/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Via Secretória , Proteínas de Transporte Vesicular/metabolismo , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Ligação Proteica , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Transporte Proteico , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Transporte Vesicular/genética
15.
Metab Eng ; 47: 488-495, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29702274

RESUMO

A synthetic pathway for production of the eukaryotic trimannosyl chitobiose glycan (mannose3-N-acetylglucosamine2, Man3GlcNAc2) and its transfer to specific asparagine residues in target proteins was previously engineered in Escherichia coli, providing this simple microbe with the ability to perform a complex post-translational protein modification. Here, we leveraged a flow cytometric fluorescence-based assay to improve Man3GlcNAc2 glycan biosynthesis in E. coli cells. Specifically, pathway improvements were identified, including reducing pathway enzyme expression levels and overexpressing nucleotide sugar biosynthesis genes, which enhanced production of lipid-linked Man3GlcNAc2 by nearly 50-fold to 13.9 µg/L. In turn, cells producing higher levels of the Man3GlcNAc2 substrate yielded up to 10 times more glycosylated acceptor protein (to ~ 14 mg/L) than their non-optimized counterparts. These results demonstrate the use of flow cytometry screening as a powerful tool for interrogating the surfaces of glyco-engineered bacteria and identifying meaningful improvements in glycan biosynthesis. We anticipate this approach will enable further optimization of bacterial glycan biosynthesis pathways using new strain engineering tools from metabolic engineering and synthetic biology.


Assuntos
Escherichia coli , Citometria de Fluxo , Glucagon , Microrganismos Geneticamente Modificados , Proteínas Recombinantes de Fusão , Escherichia coli/citologia , Escherichia coli/genética , Escherichia coli/metabolismo , Engenharia Genética , Glucagon/genética , Glicosilação , Humanos , Microrganismos Geneticamente Modificados/citologia , Microrganismos Geneticamente Modificados/genética , Microrganismos Geneticamente Modificados/metabolismo , Proteínas Recombinantes de Fusão/biossíntese , Proteínas Recombinantes de Fusão/genética
16.
Xenotransplantation ; 24(1)2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-28058735

RESUMO

Anti-CD154mAb is a powerful co-stimulation blockade agent that is efficacious in preventing rejection, even in xenogeneic settings. It has been used in the majority of successful long-term pig-to-non-human primate islet transplantation models. However, its clinical use was halted as a result of thromboembolic complications that were also observed in preclinical and clinical organ transplantation models. An anti-CD154mAb was administered to 14 streptozotocin-induced diabetic cynomolgus monkey recipients of porcine islets, some of which received the agent for many months. Monkeys were monitored for complications, and blood monitoring was carried out frequently. After euthanasia, multiple biopsies of all organs were examined for histological features of thromboembolism. Anti-CD154mAb prevented rejection of genetically engineered pig islets in all monkeys. No significant complications were attributable specifically to anti-CD154mAb. There was no evidence of thromboembolism in multiple histological sections from all major organs, including the brain. Our data suggest that in diabetic monkeys with pig islet grafts, anti-CD154mAb would appear to be an effective and safe therapy, and is not associated with thromboembolic complications.


Assuntos
Anticorpos Monoclonais/farmacologia , Ligante de CD40/imunologia , Xenoenxertos/efeitos dos fármacos , Transplante das Ilhotas Pancreáticas/imunologia , Transplante Heterólogo , Animais , Diabetes Mellitus Experimental/imunologia , Rejeição de Enxerto/imunologia , Sobrevivência de Enxerto/imunologia , Xenoenxertos/imunologia , Imunossupressores/farmacologia , Macaca fascicularis , Suínos , Transplante Heterólogo/métodos
17.
AJR Am J Roentgenol ; 208(6): 1285-1296, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28350484

RESUMO

OBJECTIVE: The purpose of this study was to conduct longitudinal analyses of radiation dose data from adult patients undergoing clinically indicated, repeat identical thoracoabdominal CT examinations. MATERIALS AND METHODS: Radiation dose data were electronically collected from 2851 subjects undergoing 12,635 repeat identical CT scans (mean number of scans per patient, 4.8; range, 2-33) in one health system. Included CT protocols were chest-abdomen-pelvis with contrast administration (n = 4621 CT studies of 1064 patients), abdomen-pelvis with contrast administration (n = 876 CT studies of 261 patients), renal stone (n = 1053 CT studies of 380 patients), and chest (n = 6085 CT studies of 1146 patients) without contrast administration. A radiation-tracking software infrastructure was adopted to extract data from DICOM headers in PACS. Size-specific dose estimate (SSDE) was calculated. RESULTS: A trend was observed toward global reduction in SSDE values with all protocols investigated (chest-abdomen-pelvis slope, -1.78; abdomen-pelvis slope, -0.82; renal stone slope, -0.83; chest slope, -0.47; p < 0.001 for all comparisons). The intraindividual analyses of radiation dose distribution showed widespread variability in SSDE values across the four protocols investigated (chest-abdomen-pelvis mean coefficient of variance, 14.02 mGy; abdomen-pelvis mean coefficient of variance, 10.26 mGy; renal stone mean coefficient of variance, 34.18 mGy; chest mean coefficient of variance, 6.74 mGy). CONCLUSION: Although there is a trend toward global reduction in radiation doses, this study showed widespread variability in the radiation dose that each patient undergoing identical repeat thoracoabdominal CT protocols absorbs. These data may provide a foundation for the future development of best-practice guidelines for patient-specific radiation dose monitoring.


Assuntos
Centros Médicos Acadêmicos/estatística & dados numéricos , Doses de Radiação , Exposição à Radiação/estatística & dados numéricos , Radiografia Abdominal/estatística & dados numéricos , Radiografia Torácica/estatística & dados numéricos , Tomografia Computadorizada por Raios X/estatística & dados numéricos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , North Carolina/epidemiologia , Radiometria/estatística & dados numéricos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Adulto Jovem
18.
Oral Health Prev Dent ; 15(3): 229-236, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28530006

RESUMO

PURPOSE: The percentage of U.S. children with poor oral health continues to be high. Kindergarten/elementary school educators could play an important role in teaching students about oral health promotion. The objectives were to assess which oral health-related web-based resources teachers consider most helpful and how teachers' attitudes, knowledge, and behavioural intentions concerning oral health-related teaching change between before and after having access to a resource website. MATERIALS AND METHODS: Web-based survey data were collected from 95 kindergarten/elementary school educators before and after they accessed a website with oral health-related information for teachers (web-link: http://media.dent.umich.edu/teachoralhealth/index.html). RESULTS: Most teachers accessed lesson plans about 'Teeth and smiling' (90%) and 'Taking care of your teeth' (88%) and the fewest accessed information about 'Nutrition and health' (42%) and 'Information for parents' (39%). On average, all materials were perceived as useful (5-point scale with 5 = 'very useful', range = 3.80 to 4.04). Responses to the question on how important dental health is for a child's ability to learn improved significantly from before to after the educational intervention (5-point scale with 5 = 'very important', 3.78 vs 4.44). Knowledge increased and behavioural intentions improved as well. The percentage of teachers who reported that they had included oral health-related material in the past was 47% and the percentage who intended to include it in the future was 65% (p < 0.001). CONCLUSIONS: Providing kindergarten/elementary school educators with web-based resource materials improves their attitudes, increases their knowledge and leads to positive behavioural intentions concerning educating their students about oral health.


Assuntos
Educação em Saúde Bucal , Internet , Saúde Bucal , Professores Escolares , Criança , Pré-Escolar , Humanos , Autorrelato
19.
Radiology ; 279(1): 269-77, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26536403

RESUMO

PURPOSE: To determine the variance in virtual monochromatic computed tomography (CT) numbers from the same lesion, comparing the two clinically available dual-energy multidetector CT hardware implementations (single-source projection-based and dual-source image-based), in a phantom-based simulated abdominal environment. MATERIALS AND METHODS: This phantom-based study was exempt from institutional review board oversight. Polyethylene terephthalate spheres (15 and 18 mm) with two iodine-to-saline dilutions (0.8 and 1.2 mg of iodine per millilliter) were serially suspended in a cylindrical polypropylene bottle filled with diluted iodinated contrast material. The bottle was placed into a 36-cm-wide torso-shaped water phantom simulating the abdomen of a medium-sized patient. Dual-energy (80/140 kVp) and single-energy (100 and 120 kVp) scans were obtained with single-source and dual-source multidetector CT implementations. Virtual monochromatic images were reconstructed at energy levels of 40-140 keV (in 10-keV increments) in either the projection-space or image-space domain. A multivariate regression analysis approach was used to investigate the effect of energy level, lesion size, lesion iodine content, and implementation type on measured CT numbers. RESULTS: There were significant differences in the attenuation values measured in the simulated lesions with the single-source projection-based platform and the dual-source image-based implementation (P < .001 for all comparisons). The magnitude of these differences was greatest at lower monochromatic energy levels and at lower iodine concentrations (average difference at 40 keV: 25.7 HU; average difference at 140 keV: 7 HU). The monochromatic energy level and the lesion iodine concentration had a significant effect on the difference in the measured attenuation values between the two implementations, which indicates that the two imaging platforms respond differently to changes in investigated variables (P < .001 for all comparisons). CONCLUSION: There is a statistically significant variance in virtual monochromatic CT numbers from the same lesion examined with single-source projection-based and dual-source image-based implementations. The magnitude of the variance is a function of the selected energy level and the lesion iodine content.


Assuntos
Tomografia Computadorizada Multidetectores/métodos , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Cor , Meios de Contraste , Humanos , Imagens de Fantasmas , Imagem Radiográfica a Partir de Emissão de Duplo Fóton/métodos
20.
Eur Radiol ; 26(1): 157-66, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25991484

RESUMO

OBJECTIVES: To assess the effect of automatic tube potential selection (ATPS) on radiation dose, image quality, and lesion detectability in paediatric abdominopelvic CT and CT angiography (CTA). METHODS: A paediatric modular phantom with contrast inserts was examined with routine pitch (1.4) and high pitch (3.0) using a standard abdominopelvic protocol with fixed 120 kVp, and ATPS with variable kVp in non-contrast, contrast-enhanced, and CTA mode. The volume CT dose index (CTDIvol), contrast-to-noise ratio (CNR) and lesion detectability index (d') were compared between the standard protocol and ATPS examinations. RESULTS: CTDIvol was reduced in all routine pitch ATPS examinations, with dose reductions of 27-52 % in CTA mode (P < 0.0001), 15-33 % in contrast-enhanced mode (P = 0.0003) and 8-14 % in non-contrast mode (P = 0.03). Iodine and soft tissue insert CNR and d' were improved or maintained in all ATPS examinations. kVp and dose were reduced in 25 % of high pitch ATPS examinations and in none of the full phantom examinations obtained after a single full phantom localizer. CONCLUSIONS: ATPS reduces radiation dose while maintaining image quality and lesion detectability in routine pitch paediatric abdominopelvic CT and CTA, but technical factors such as pitch and imaging range must be considered to optimize ATPS benefits. KEY POINTS: ATPS automatically individualizes CT scan technique for each patient. ATPS lowers radiation dose in routine pitch pediatric abdominopelvic CT and CTA. There is no loss of image quality or lesion detectability with ATPS. Pitch and scan range impact the effectiveness of ATPS dose reduction.


Assuntos
Angiografia/instrumentação , Pelve/diagnóstico por imagem , Imagens de Fantasmas , Radiografia Abdominal/instrumentação , Tomografia Computadorizada por Raios X/instrumentação , Abdome , Criança , Desenho de Equipamento , Humanos , Doses de Radiação
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