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1.
J Am Coll Radiol ; 21(6S): S65-S78, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38823956

RESUMO

Chronic hand and wrist pain is a common presenting complaint. The intricate anatomy results in a variety of pain generators-multiple bones, articular cartilage, intrinsic ligaments, triangular fibrocartilage complex, joint capsules and synovium, tendons and tendon sheaths, muscles, and nerves-in a compact space. The need for imaging and the choice of the appropriate imaging modality are best determined by the patient's presentation, physical examination, and the clinician's working differential diagnosis. Radiography is usually appropriate as the initial imaging study in the evaluation of chronic hand or wrist pain. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.


Assuntos
Dor Crônica , Medicina Baseada em Evidências , Sociedades Médicas , Humanos , Dor Crônica/diagnóstico por imagem , Estados Unidos , Mãos/diagnóstico por imagem , Diagnóstico Diferencial , Artralgia/diagnóstico por imagem
3.
J Am Coll Radiol ; 20(11S): S413-S432, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-38040462

RESUMO

This article reviews evidence for performing various imaging studies in patients with total hip prostheses. Routine follow-up is generally performed with radiography. Radiographs are also usually the initial imaging modality for patients with symptoms related to the prosthesis. Following acute injury with pain, noncontrast CT may add information to radiographic examination regarding the presence and location of a fracture, component stability, and bone stock. Image-guided joint aspiration, noncontrast MRI, and white blood cell scan and sulfur colloid scan of the hip, are usually appropriate studies for patients suspected of having periprosthetic infection. For evaluation of component loosening, wear, and/or osteolysis, noncontrast CT or MRI are usually appropriate studies. Noncontrast MRI is usually appropriate for identifying adverse reaction to metal debris related to metal-on-metal articulations. For assessing patients after hip arthroplasty, who have trochanteric pain and nondiagnostic radiographs, ultrasound, or MRI are usually appropriate studies. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.


Assuntos
Artroplastia de Quadril , Humanos , Artroplastia de Quadril/efeitos adversos , Imageamento por Ressonância Magnética/métodos , Dor , Radiografia , Cintilografia , Sociedades Médicas , Estados Unidos
4.
J Am Coll Radiol ; 20(11S): S433-S454, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-38040463

RESUMO

Total knee arthroplasty is the most commonly performed joint replacement procedure in the United States. This manuscript will discuss the recommended imaging modalities for six clinical variants; 1. follow-up of symptomatic or asymptomatic patients with a total knee arthroplasty. Initial imaging, 2. Suspected infection after total knee arthroplasty. Additional imaging following radiographs, 3. Pain after total knee arthroplasty. Infection excluded. Suspect aseptic loosening or osteolysis or instability. Additional imaging following radiographs, 4. Pain after total knee arthroplasty. Suspect periprosthetic or hardware fracture. Additional imaging following radiographs, 5. Pain after total knee arthroplasty. Measuring component rotation. Additional imaging following radiographs, and 6. Pain after total knee arthroplasty. Suspect periprosthetic soft-tissue abnormality unrelated to infection, including quadriceps or patellar tendinopathy. Additional imaging following radiographs. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.


Assuntos
Artroplastia do Joelho , Dor Crônica , Humanos , Artralgia/diagnóstico por imagem , Dor Crônica/diagnóstico por imagem , Diagnóstico por Imagem/métodos , Radiografia , Sociedades Médicas , Estados Unidos
5.
Cureus ; 15(5): e38706, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37292538

RESUMO

Fungal endocarditis is an uncommon and dangerous disorder of the heart. The two most frequent etiologic fungi discovered to be responsible for fungal endocarditis are Aspergillus and Candida species. It is difficult to make a diagnosis of fungal endocarditis; a comprehensive assessment must be carried out, and specific diagnostic requirements must be completed. One of the main causes of endocarditis that physicians deal with in the hospital is intravenous drug abuse, but we never hear about transdermal drug abuse causing endocarditis. Here we present an interesting case of a 33-year-old male patient that presents to the hospital with non-specific complaints, and he was found to have fungemia. It was found out that the patient was using a kitchen appliance to cause dermal abrasion on his skin to increase the absorption rate of his fentanyl patch. Patient also suffers from trypanophobia, so he declined any surgical intervention and wanted lifelong oral medication therapy.

6.
J Am Coll Radiol ; 20(5S): S20-S32, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-37236743

RESUMO

Evaluation for suspected inflammatory arthritis as a cause for chronic extremity joint pain often relies on imaging. It is essential that imaging results are interpreted in the context of clinical and serologic results to add specificity because there is significant overlap of imaging findings among the various types of arthritis. This document provides recommendations for imaging evaluation of specific types of inflammatory arthritis, including rheumatoid arthritis, seronegative spondyloarthropathy, gout, calcium pyrophosphate dihydrate disease (or pseudogout), and erosive osteoarthritis. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances in which peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.


Assuntos
Dor Crônica , Artropatias por Cristais , Osteoartrite , Humanos , Estados Unidos , Dor Crônica/etiologia , Sociedades Médicas , Medicina Baseada em Evidências , Extremidades , Osteoartrite/diagnóstico por imagem , Artropatias por Cristais/complicações , Artralgia/etiologia
7.
J Am Coll Radiol ; 20(5S): S33-S48, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-37236751

RESUMO

Chronic hip pain is a frequent chief complaint for adult patients who present for evaluation in a variety of clinical practice settings. Following a targeted history and physical examination, imaging plays a vital role in elucidating the etiologies of a patient's symptoms, as a wide spectrum of pathological entities may cause chronic hip pain. Radiography is usually the appropriate initial imaging test following a clinical examination. Depending on the clinical picture, advanced cross-sectional imaging may be subsequently performed for further evaluation. This documents provides best practice for the imaging workup of chronic hip pain in patients presenting with a variety of clinical scenarios. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.


Assuntos
Medicina Baseada em Evidências , Sociedades Médicas , Humanos , Estados Unidos , Dor
8.
J Am Coll Radiol ; 20(5S): S49-S69, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-37236752

RESUMO

Chronic shoulder pain is an extremely common presenting complaint. Potential pain generators include the rotator cuff tendons, biceps tendon, labrum, glenohumeral articular cartilage, acromioclavicular joint, bones, suprascapular and axillary nerves, and the joint capsule/synovium. Radiographs are typically the initial imaging study obtained in patients with chronic shoulder pain. Further imaging may often be required, with modality chosen based on patient symptoms and physical examination findings, which may lead the clinician to suspect a specific pain generator. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.


Assuntos
Dor de Ombro , Sociedades Médicas , Humanos , Estados Unidos , Dor de Ombro/diagnóstico por imagem , Medicina Baseada em Evidências , Diagnóstico por Imagem
9.
Hand (N Y) ; 18(1_suppl): 119S-125S, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-35579211

RESUMO

BACKGROUND: Although electrical stimulation (ES) can improve nerve regeneration, the impact of nerve block, such as lidocaine (Lido), on the therapeutic benefits of ES remains unclear. We used a rat tibial nerve transection-and-repair model to explore how either preoperative (PreOp) or postoperative (PostOp) nerve block affects ES-related improvement in regeneration. METHODS: Lewis rats were used in 1 of 2 studies. The first evaluated the effects of extraneural Lido on both healthy and injured nerves. In the second study, rats were randomized to 5 experimental groups: No ES (negative control), PreOp Lido, ES + PreOp Lido, PostOp + ES, and ES (positive control). All groups underwent tibial nerve transection and repair. In both studies, nerves were harvested for histological analysis of regeneration distal to the injury site. RESULTS: Application of extraneural Lido did not damage healthy or injured nerve based on qualitative histological observations. In the context of nerve transection and repair, the ES group exhibited improved axon regeneration at 21 days measured by the total number of myelinated fibers compared with No ES. Fiber density and percentage of neural tissue in the ES group were greater than those in both No ES and PreOp Lido + ES groups. ES + PostOp Lido was not different from No ES or ES group. CONCLUSIONS: Extraneural application of Lido did not damage nerves. Electrical stimulation augmented nerve regeneration, but Lido diminished the ES-related improvement in nerve regeneration. Clinical studies on the effects of ES to nerve regeneration may need to consider nerve block as a variable affecting ES outcome.


Assuntos
Terapia por Estimulação Elétrica , Lidocaína , Animais , Ratos , Axônios/fisiologia , Lidocaína/farmacologia , Regeneração Nervosa/fisiologia
10.
Skeletal Radiol ; 52(6): 1247-1250, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36194246

RESUMO

Autism spectrum disorder (ASD) is an increasingly common neurodevelopmental disorder associated with impairments in postural control and repetitive patterns of behavior. Here, we describe two cases of adventitial bursitis of the dorsolateral feet in patients with ASD presenting as mass-like lesions. Both patients habitually sat in the W-position and were treated with ultrasound-guided aspirations with immediate relief of symptoms.


Assuntos
Transtorno do Espectro Autista , Bursite , Humanos , Transtorno do Espectro Autista/diagnóstico por imagem , Transtorno do Espectro Autista/complicações , Bursite/diagnóstico por imagem , Bursite/complicações
11.
J Am Coll Radiol ; 19(11S): S417-S432, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36436967

RESUMO

Osteoporosis constitutes a significant public health risk. An estimated 10.2 million adults in the United States >50 years of age have osteoporosis, a systemic condition that weakens the bones increasing the susceptibility for fractures. Approximately one-half of women and nearly one-third of men >50 years of age will sustain an osteoporotic fracture. These fractures are associated with a decrease in quality of life, diminished physical function, and reduced independence. Dual-energy X-ray absorptiometry (DXA) is the primary imaging modality used to screen for osteoporosis in women >65 years of age and men >70 years of age. DXA may be used in patients <65 years of age to evaluate bone mass density if there are additional risk factors. In certain situations, vertebral fracture assessment and trabecular bone score may further predict fracture risk, particularly in patients who are not yet osteoporotic but are in the range of osteopenia. Quantitative CT is useful in patients with advanced degenerative changes in the spine. Given the proven efficacy of pharmacologic therapy, the role of imaging to appropriately identify and monitor high-risk individuals is critical in substantially reducing osteoporosis-associated morbidity and mortality, and reducing the considerable cost to the health care system. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.


Assuntos
Densidade Óssea , Osteoporose , Masculino , Humanos , Feminino , Estados Unidos , Qualidade de Vida , Sociedades Médicas , Medicina Baseada em Evidências , Diagnóstico Diferencial , Osteoporose/diagnóstico por imagem
12.
J Am Coll Radiol ; 19(5S): S53-S66, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35550805

RESUMO

Shoulder arthroplasty is a common orthopedic procedure with a complication rate reported to be as high as 39.8% and revision rates as high as 11%. Symptoms related to postoperative difficulties include activity-related pain, decreased range of motion, and apprehension. Some patients report immediate and persistent dissatisfaction, although others report a symptom-free postoperative period followed by increasing pain and decreasing shoulder function and mobility. Imaging plays an important role in diagnosing postoperative complications of shoulder arthroplasties. The imaging algorithm should always begin with radiographs. The selection of the next imaging modality depends on several factors, including findings on the initial imaging study, clinical suspicion of an osseous versus soft-tissue injury, and clinical suspicion of infection.The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.


Assuntos
Artroplastia do Ombro , Sociedades Médicas , Diagnóstico por Imagem/métodos , Medicina Baseada em Evidências , Humanos , Dor , Estados Unidos
13.
Cureus ; 14(4): e24129, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35573586

RESUMO

Introduction The optimal treatment regimen for herpes simplex-1 (HSV-1) encephalitis is ill-defined. Current guidelines recommend the initiation of acyclovir in all suspected cases of encephalitis; however, there is limited research regarding the details of acyclovir treatment or the adjuvant use of corticosteroids. Specifically, there is a paucity of evidence-based guidelines detailing the optimal management of HSV-1 encephalitis in immunocompetent patients. In this study, we conducted a review of cases of immunocompetent patients with HSV-1 encephalitis to compare patterns in treatment and outcomes.  Methods A review of the literature was performed using PubMed using the terms herpes encephalitis, HSV, herpes zoster, and immunocompetent to identify cases of HSV-1 encephalitis in immunocompetent patients. The results were screened for cases describing the treatment regimen of HSV-1 encephalitis-positive, immunocompetent patients.  Results Six cases were identified. All six patients were treated with acyclovir with one patient receiving adjuvant corticosteroid therapy. Additionally, three patients were found to have acyclovir resistance and were transitioned to foscarnet. Eventually, one patient expired, two patients recovered with chronic morbidities of varying severity, and three patients made a full recovery.  Discussion Inconsistencies in the patient's disease course, therapeutic regimen, and comorbidities could all play a role in the varying case outcomes. While the optimal timing and composition of therapies in HSV-1 encephalitis in immunocompetent patients are still unclear, it seems the timely administration of antiviral treatment remains essential. Further research is needed to optimize HSV-1 encephalitis therapeutic regimens and improve patient outcomes.

14.
Clin Sports Med ; 40(4): 801-819, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34509212

RESUMO

Utilization of musculoskeletal ultrasound, in particular for sports medicine, has dramatically increased in recent years. Ultrasound is an important adjunct tool to physical examination and other imaging methods in the evaluation and management of the injured athlete. It offers unique advantages in specific clinical scenarios. Dedicated training and a standardized scanning technique are important to overcome the inherent operator dependence and avoid diagnostic pitfalls. Ultrasound guidance can also improve accuracy in targeted percutaneous injection therapies. This article reviews the general ultrasound appearance of muscle, tendon, ligament, and nerve abnormalities in the athlete with a focus on sport-specific injuries.


Assuntos
Traumatismos em Atletas , Sistema Musculoesquelético , Medicina Esportiva , Traumatismos em Atletas/diagnóstico por imagem , Traumatismos em Atletas/terapia , Humanos , Sistema Musculoesquelético/lesões , Ultrassonografia
15.
J Phys Chem Lett ; 12(29): 6955-6960, 2021 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-34283593

RESUMO

A method of uncertainty quantification on a quantum circuit using three samples for the Rh(111)-catalyzed CO oxidation reaction is demonstrated. Three parametrized samples of a reduced, linearized microkinetic model populate a single block diagonal matrix for a quantum circuit. This approach leverages the logarithmic scaling of the number of qubits with respect to matrix size. The Harrow, Hassidim, and Lloyd (HHL) algorithm for solving linear systems is employed, and the results are compared with the classical results. This application area of uncertainty quantification in chemical kinetics can experience a quantum advantage using the method reported here, although issues related to larger systems are discussed.

16.
J Phys Chem Lett ; 12(1): 592-597, 2021 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-33382628

RESUMO

A CO oxidation microkinetic model is set up for a quantum circuit. The CO oxidation microkinetic model, and microkinetic models in general, exhibit an advantage of not requiring an encoding step because of being a subclass of systems of equations. The microkinetic model is cast as a nonlinear set of equations at first. Then, a linearizing approximation is made, and the resulting linear set of equations may be iterated to converge to the solution to the nonlinear set of equations. In this CO oxidation, the linearized set of equations is realized to chemical accuracy with one iteration. Current limitations in executing the quantum circuit to obtain the solution are discussed.

17.
Skeletal Radiol ; 50(5): 921-925, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33021682

RESUMO

OBJECTIVE: To determine the prevalence of shoulder (specifically labral) abnormalities on MRI in a young non-athletic asymptomatic cohort. We hypothesize that this population will have fewer labral abnormalities than an athletic population. MATERIALS AND METHODS: In this cross-sectional study, non-athletic young adults age 18-29 with no history of shoulder pain received bilateral shoulder MRIs. A total of 58 total shoulder MRIs were completed on a 3-T MRI scanner (PRISMA-Fit Siemens Medical). MRIs were read by two board-certified fellowship-trained musculoskeletal radiologists at two time points 3 months apart to determine prevalence of labral and other shoulder anatomy abnormalities. Kappa statistics and the associated 95% confidence intervals were computed for inter/intra-reader reliability. Fisher's exact test was used to compare rates of abnormalities in our study with a similarly designed study involving ice hockey athletes. RESULTS: Prevalence of labral abnormalities was 9% (5/58). Kappa coefficient was 1.0 for both readers for intra-reader reliability and 0.57 for inter-reader reliability of labral abnormalities. We further compared our results in asymptomatic athletes with previously published work using the same protocol at our institution. The prevalence of labral abnormalities on MRI in asymptomatic professional and collegiate ice hockey players (49 imaged shoulders) was 24%, which demonstrated a statistically significant (p value < 0.05) difference compared with our data with a p value of 0.03. CONCLUSIONS: Non-athletic young adults with no history of shoulder pain/injury had an overall prevalence of shoulder MRI abnormalities less than asymptomatic professional and collegiate ice hockey players in a similarly designed study.


Assuntos
Articulação do Ombro , Ombro , Adolescente , Adulto , Estudos Transversais , Humanos , Imageamento por Ressonância Magnética , Prevalência , Reprodutibilidade dos Testes , Articulação do Ombro/diagnóstico por imagem , Adulto Jovem
18.
J Am Coll Radiol ; 17(5S): S226-S238, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32370967

RESUMO

Although primary bone tumors are relatively uncommon, appropriate imaging evaluation is essential when they are suspected or incidentally detected. In almost all cases, radiographs are the most appropriate initial imaging study for screening and characterization of primary bone tumors. Radiographs often provide sufficient information for diagnosis and to guide the treating clinician. However, when conventional radiographs alone are inadequate, they still often guide the selection of the most appropriate next step for advanced imaging. MRI and CT are typically the most appropriate next step. MRI provides excellent soft-tissue contrast allowing for evaluation of the tissue composition (such as fat, hemorrhage, fluid levels) and anatomic extent of bone tumors. CT provides complementary information, with its ability to detect subtle matrix mineralization or periosteal reaction that may not be seen on radiographs or MRI. This publication focuses on six common variants to guide diagnosis and management of primary bone tumors. In addition to conventional radiographs, appropriate use of MRI, CT, PET/CT, bone scan, and ultrasound are discussed. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.


Assuntos
Neoplasias Ósseas , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Neoplasias Ósseas/diagnóstico por imagem , Humanos , Imageamento por Ressonância Magnética , Sociedades Médicas , Ultrassonografia , Estados Unidos
19.
J Phys Chem Lett ; 11(12): 4917-4922, 2020 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-32459487

RESUMO

The adsorption energies of intermediates of the dry reforming of methane reaction (DRM CH4 + CO2 ⇔ 2CO + 2H2) using Rh(111) are approximated. Graph theory creates descriptors of the intermediates. The information recorded in these descriptors includes the elemental identities of each atom, its neighbors, and its next-nearest neighbors. Graph theory is employed because it is a rapid approximation of more expensive density functional theory (DFT) calculations and because the descriptors created by graph theory are both human and machine interpretable. DRM contains a significant number of adsorbates, and side reactions, including reverse water-gas shift, may occur simultaneously. Therefore, DRM is well-poised for analysis by a graph theory model to predict large numbers of adsorption energies. A portion of adsorbates were calculated with DFT. Then, predictions were reported for the remaining adsorption energies not calculated with DFT.

20.
J Chem Inf Model ; 60(3): 1290-1301, 2020 03 23.
Artigo em Inglês | MEDLINE | ID: mdl-32091880

RESUMO

In a departure from conventional chemical approaches, data-driven models of chemical reactions have recently been shown to be statistically successful using machine learning. These models, however, are largely black box in character and have not provided the kind of chemical insights that historically advanced the field of chemistry. To examine the knowledgebase of machine-learning models-what does the machine learn-this article deconstructs black-box machine-learning models of a diverse chemical reaction data set. Through experimentation with chemical representations and modeling techniques, the analysis provides insights into the nature of how statistical accuracy can arise, even when the model lacks informative physical principles. By peeling back the layers of these complicated models we arrive at a minimal, chemically intuitive model (and no machine learning involved). This model is based on systematic reaction-type classification and Evans-Polanyi relationships within reaction types which are easily visualized and interpreted. Through exploring this simple model, we gain deeper understanding of the data set and uncover a means for expert interactions to improve the model's reliability.


Assuntos
Aprendizado de Máquina , Reprodutibilidade dos Testes
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