Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 96
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Nature ; 569(7755): 241-244, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31068724

RESUMO

The production of elements by rapid neutron capture (r-process) in neutron-star mergers is expected theoretically and is supported by multimessenger observations1-3 of gravitational-wave event GW170817: this production route is in principle sufficient to account for most of the r-process elements in the Universe4. Analysis of the kilonova that accompanied GW170817 identified5,6 delayed outflows from a remnant accretion disk formed around the newly born black hole7-10 as the dominant source of heavy r-process material from that event9,11. Similar accretion disks are expected to form in collapsars (the supernova-triggering collapse of rapidly rotating massive stars), which have previously been speculated to produce r-process elements12,13. Recent observations of stars rich in such elements in the dwarf galaxy Reticulum II14, as well as the Galactic chemical enrichment of europium relative to iron over longer timescales15,16, are more consistent with rare supernovae acting at low stellar metallicities than with neutron-star mergers. Here we report simulations that show that collapsar accretion disks yield sufficient r-process elements to explain observed abundances in the Universe. Although these supernovae are rarer than neutron-star mergers, the larger amount of material ejected per event compensates for the lower rate of occurrence. We calculate that collapsars may supply more than 80 per cent of the r-process content of the Universe.

2.
J Am Acad Dermatol ; 91(2): 324-330, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38663749

RESUMO

Correct coding is an important component of effective dermatology practice management. Over the past several years there have been updates to many commonly used codes within dermatology. This review highlights many of these updates, such as: the skin biopsy codes have been subdivided to reflect the different biopsy techniques. The definition of complex linear repairs has been updated and clarified. Outpatient and inpatient evaluation and management visits have new coding guidelines to determine level of care. Dermatopathology consultation codes have been updated and category III codes related to digital pathology have been created. Understanding the details and nuances of each of these categories of codes is vital to ensuring appropriate coding is performed.


Assuntos
Codificação Clínica , Dermatologia , Dermatologia/normas , Dermatologia/métodos , Humanos , Dermatopatias/diagnóstico , Dermatopatias/patologia , Dermatopatias/terapia , Biópsia , Classificação Internacional de Doenças
3.
Phys Rev Lett ; 131(23): 231402, 2023 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-38134805

RESUMO

We perform three-dimensional general-relativistic magnetohydrodynamic simulations with weak interactions of binary neutron-star (BNS) mergers resulting in a long-lived remnant neutron star, with properties typical of galactic BNS and consistent with those inferred for the first observed BNS merger GW170817. We demonstrate self-consistently that within ≲30 ms postmerger magnetized (σ∼5-10) incipient jets emerge with asymptotic Lorentz factor Γ∼5-10, which successfully break out from the merger debris within ≲20 ms. A fast (v≲0.6c), magnetized (σ∼0.1) wind surrounds the jet core and generates a UV/blue kilonova precursor on timescales of hours, similar to the precursor signal due to free neutron decay in fast dynamical ejecta. Postmerger ejecta are quickly dominated by magnetohydrodynamically driven outflows from an accretion disk. We demonstrate that, within only 50 ms postmerger, ≳2×10^{-2}M_{⊙} of lanthanide-free, quasispherical ejecta with velocities ∼0.1-0.2c is launched, yielding a kilonova signal consistent with GW170817 on timescales of ≲5 d.

4.
J Drugs Dermatol ; 22(12): 1153-1159, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-38051841

RESUMO

BACKGROUND: The International Dermatology Outcome Measures (IDEOM) is a non-profit organization dedicated to the advancement of evidence-based, consensus-driven outcome measures in dermatological diseases. Researchers and stakeholders from various backgrounds collaborate to develop these objective benchmark metrics to further advance treatment and management of dermatological conditions. SUMMARY: The 2022 IDEOM Annual Meeting was held on June 17-18, 2022. Leaders and stakeholders from the hidradenitis suppurativa, acne, vitiligo, actinic keratosis, alopecia areata, itch, cutaneous lymphoma, and psoriatic disease workgroups discussed the progress of their respective outcome-measures research. This report summarizes each workgroup's updates from 2022 and their next steps as established during the 2022 IDEOM Annual Meeting. J Drugs Dermatol. 2023;22(12):1153-1159 doi:10.36849/JDD.7615.


Assuntos
Alopecia em Áreas , Dermatologia , Psoríase , Neoplasias Cutâneas , Humanos , Avaliação de Resultados em Cuidados de Saúde , Psoríase/tratamento farmacológico
5.
Dermatology ; 238(4): 649-656, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35124665

RESUMO

BACKGROUND: Mobile health (mHealth) consumer applications (apps) have been integrated with deep learning for skin cancer risk assessments. However, prospective validation of these apps is lacking. OBJECTIVES: To identify the diagnostic accuracy of an app integrated with a convolutional neural network for the detection of premalignant and malignant skin lesions. METHODS: We performed a prospective multicenter diagnostic accuracy study of a CE-marked mHealth app from January 1 until August 31, 2020, among adult patients with at least one suspicious skin lesion. Skin lesions were assessed by the app on an iOS or Android device after clinical diagnosis and before obtaining histopathology. The app outcome was compared to the histopathological diagnosis, or if not available, the clinical diagnosis by a dermatologist. The primary outcome was the sensitivity and specificity of the app to detect premalignant and malignant skin lesions. Subgroup analyses were conducted for different smartphone types, the lesion's origin, indication for dermatological consultation, and lesion location. RESULTS: In total, 785 lesions, including 418 suspicious and 367 benign control lesions, among 372 patients (50.8% women) with a median age of 71 years were included. The app performed at an overall 86.9% (95% CI 82.3-90.7) sensitivity and 70.4% (95% CI 66.2-74.3) specificity. The sensitivity was significantly higher on the iOS device compared to the Android device (91.0 vs. 83.0%; p = 0.02). Specificity calculated on benign control lesions was significantly higher than suspicious skin lesions (80.1 vs. 45.5%; p < 0.001). Sensitivity was higher in skin fold areas compared to smooth skin areas (92.9 vs. 84.2%; p = 0.01), while the specificity was higher for lesions in smooth skin areas (72.0 vs. 56.6%; p = 0.02). CONCLUSION: The diagnostic accuracy of the mHealth app is far from perfect, but is potentially promising to empower patients to self-assess skin lesions before consulting a health care professional. An additional prospective validation study, particularly for suspicious pigmented skin lesions, is warranted. Furthermore, studies investigating mHealth implementation in the lay population are needed to demonstrate the impact on health care systems.


Assuntos
Melanoma , Aplicativos Móveis , Dermatopatias , Neoplasias Cutâneas , Telemedicina , Adulto , Idoso , Inteligência Artificial , Detecção Precoce de Câncer , Feminino , Humanos , Masculino , Melanoma/patologia , Neoplasias Cutâneas/diagnóstico , Neoplasias Cutâneas/patologia
6.
Dermatology ; 238(3): 430-437, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34537770

RESUMO

BACKGROUND: The International Dermatology Outcome Measures (IDEOM) initiative is a non-profit organization that aims to develop evidence-based outcome measurements to evaluate the impact of treatments for patients with dermatological disease. IDEOM includes all key stakeholders in dermatology (patient, physician, industry, insurer, and government) during the process of developing such outcome measurements. SUMMARY: Here, we provide an update of IDEOM activities that were presented at the 2020 IDEOM Virtual Annual Meeting (October 23-24, 2020). During the meeting, multiple IDEOM workgroups (psoriasis, psoriatic arthritis, hidradenitis suppurativa, acne, pyoderma gangrenosum, and actinic keratosis) shared their progress to date, as well as future directions in developing and validating Patient-Reported Outcome Measures. Updates on demonstrating efficacy in clinicals trials by the US Food and Drug Administration are also summarized. KEY MESSAGES: In this report, we summarize the work presented by each IDEOM workgroup (psoriasis, psoriatic arthritis, hidradenitis suppurativa, acne, pyoderma gangrenosum, and actinic keratosis) at the 2020 IDEOM Virtual Annual Meeting.


Assuntos
Acne Vulgar , Artrite Psoriásica , Dermatologia , Hidradenite Supurativa , Ceratose Actínica , Psoríase , Pioderma Gangrenoso , Artrite Psoriásica/diagnóstico , Artrite Psoriásica/tratamento farmacológico , Humanos , Avaliação de Resultados em Cuidados de Saúde , Psoríase/terapia
7.
Phys Rev Lett ; 126(25): 251101, 2021 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-34241510

RESUMO

A compact accretion disk may be formed in the merger of two neutron stars or of a neutron star and a stellar-mass black hole. Outflows from such accretion disks have been identified as a major site of rapid neutron-capture (r-process) nucleosynthesis and as the source of "red" kilonova emissions following the first observed neutron-star merger GW170817. We present long-term general-relativistic radiation magnetohydrodynamic simulations of a typical postmerger accretion disk at initial accretion rates of M[over ˙]∼1 M_{⊙} s^{-1} over 400 ms postmerger. We include neutrino radiation transport that accounts for the effects of neutrino fast flavor conversions dynamically. We find ubiquitous flavor oscillations that result in a significantly more neutron-rich outflow, providing lanthanide and 3rd-peak r-process abundances similar to solar abundances. This provides strong evidence that postmerger accretion disks are a major production site of heavy r-process elements. A similar flavor effect may allow for increased lanthanide production in collapsars.

8.
J Drugs Dermatol ; 20(7): 752-754, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34231993

RESUMO

An important function of skin is prevention of water loss. When the normal skin barrier breaks down, strategies to treat dry skin include occlusives and humectants. An important physiological process for retaining water in epidermal cells is the taurine transporter (TauT). The TauT is activated within minutes after the skin is exposed to irritation, dehydration, ultraviolet radiation, and other stressors. A novel product comprising two patented technologies delivers cytoprotective osmoregulation and ingredients for optimum moisture management (Tetros® ULTRA, Intense Hydration for Stressed Skin; TetraDerm™ Group LLC, Grosse Pointe, MI). The product has been formulated with natural physiological lipid ceramides, free fatty acids, and cholesterol esters, which restore and protect the stratum corneum moisture barrier. It also contains a retinoid activator of the TauT to stimulate osmoregulation. The selected lipids and lipid precursors are present in the product in ratios that resemble the natural complexity of biological membranes. The product is also formulated with different nano- and micro-compartments that deliver hydrophilic and hydrophobic actives together, with different rates and depth of delivery, without changing composition or concentrations of excipients. The formulation enables penetration through stratum corneum and epidermis without disturbing normal skin barrier function. Controlled ingredient release and penetration depth enhance the capability of lipid precursors to promote skin lipid biosynthesis. These product characteristics lend themselves to widespread application in numerous dermatologic disorders without compromising the normal barrier function of the skin. J Drugs Dermatol. 2021;20(7):752-754. doi:10.36849/JDD.5749.


Assuntos
Pele , Administração Cutânea , Ceramidas , Epiderme , Raios Ultravioleta
9.
Dermatol Surg ; 46(2): 186-191, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-30939523

RESUMO

BACKGROUND: Dermatologists routinely perform office-based surgical procedures that result in cutaneous wounds. Wound care instructions are an important resource for postoperative patients. As there is no consensus on the ideal wound care regimen after dermatologic procedures, recommendations may vary. OBJECTIVE: To evaluate the current recommendations for wound care following dermatologic procedures. METHODS: The authors conducted a cross-sectional assessment of dermatology wound care handouts available online. The handouts were evaluated based on predefined parameters: topical agent recommendations for wound healing, caution against topical antibiotic use, and discussion of scarring, infection, bleeding, analgesia, and lifestyle considerations. RESULTS: A total of 169 handouts were evaluated. The majority (84%) recommended the application of petrolatum-based products, specifically Vaseline (75%) and Aquaphor (43%). Nearly half (43%) recommended the use of topical antibiotics, whereas 24% advised patients to avoid antibiotic ointments. Handouts variably addressed scarring (36%), infection (72%), bleeding (69%), pain (66%), and lifestyle modifications (64%). CONCLUSION: The instructions provided in dermatology patient handouts are highly variable, with various topical agents being recommended for wound healing. Topical antibiotics are not indicated for prophylaxis in clean dermatologic procedures but are still widely used. Greater efforts should be made to ensure that patients receive consistent and evidence-based wound care guidance.


Assuntos
Procedimentos Cirúrgicos Dermatológicos/efeitos adversos , Educação de Pacientes como Assunto/estatística & dados numéricos , Autocuidado/estatística & dados numéricos , Ferida Cirúrgica/terapia , Cicatrização/fisiologia , Administração Tópica , Antibacterianos/administração & dosagem , Antibioticoprofilaxia/métodos , Cicatriz/etiologia , Cicatriz/prevenção & controle , Estudos Transversais , Dermatologia/normas , Dermatologia/estatística & dados numéricos , Humanos , Pomadas/administração & dosagem , Dor Pós-Operatória/etiologia , Dor Pós-Operatória/prevenção & controle , Educação de Pacientes como Assunto/normas , Hemorragia Pós-Operatória/etiologia , Hemorragia Pós-Operatória/prevenção & controle , Padrões de Prática Médica/normas , Padrões de Prática Médica/estatística & dados numéricos , Autocuidado/métodos , Autocuidado/normas , Ferida Cirúrgica/complicações , Ferida Cirúrgica/fisiopatologia , Infecção da Ferida Cirúrgica/etiologia , Infecção da Ferida Cirúrgica/prevenção & controle , Cicatrização/efeitos dos fármacos
10.
J Drugs Dermatol ; 19(11): 1101-1108, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-33196750

RESUMO

BACKGROUND: Clinical and economic comparisons of therapies for plaque psoriasis are regularly updated following each new devel- opment in the field. With the recent availability of a novel accessory (Multi Micro DoseTM [MMD®] tip) for the 308nm excimer laser (XTRAC®, Strata Skin Sciences, Horsham, PA), which can determine and deliver an optimal therapeutic dose (OTDTM) of ultraviolet-B light in an improved protocol, the need for comparative health-economic assessment recurs. To this end, a comprehensive evaluation of treatment-related costs was undertaken from the payer perspective. Results show that outcomes are influenced by many factors; most importantly, the severity and extent of disease, treatment selection, and patient preference, as well as compliance, adherence, and persistence with care. Among study comparators, the 308nm excimer laser – XTRAC – with its latest MMD enhancement, is safe and delivers incremental clinical benefits with the potential for significant cost savings. These benefits are particularly relevant today in the context of SARS-CoV-2 virus and the COVid-19 pandemic. J Drugs Dermatol. 2020;19(11):1101-1108. doi:10.36849/JDD.2020.5510.


Assuntos
Infecções por Coronavirus , Custos de Cuidados de Saúde/estatística & dados numéricos , Pandemias , Pneumonia Viral , Psoríase/terapia , COVID-19 , Análise Custo-Benefício , Humanos , Lasers de Excimer/uso terapêutico , Cooperação do Paciente , Preferência do Paciente , Psoríase/economia , Psoríase/patologia , Índice de Gravidade de Doença , Terapia Ultravioleta/economia , Terapia Ultravioleta/métodos
11.
Dermatol Online J ; 26(1)2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32155020

RESUMO

Medical board organizations have accumulated large asset balances, in part due to the monetization of physician board recertification, as well as capital gains in positive investment conditions. Physicians across the country have raised concerns regarding the effectiveness and efficiency of existing recertification processes, to which the American Board of Medical Specialties and independent accreditation boards have responded with newly instituted changes. The present article analyzes the publicly available F990 tax forms of the medical boards in an effort to provide data to the ongoing debate. Although some boards have begun to mobilize assets in recent years, many continue to accumulate wealth. It remains to be seen whether the new recertification programs will bring about change or perpetuate organizational wealth.


Assuntos
Certificação/economia , Declarações Financeiras/tendências , Conselhos de Especialidade Profissional/economia , Acreditação/economia , Conselhos de Especialidade Profissional/organização & administração , Conselhos de Especialidade Profissional/tendências , Estados Unidos
12.
Dermatol Online J ; 26(10)2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-33147665

RESUMO

INTRODUCTION: Actinic keratosis (AK) is a skin condition arising from chronic exposure to ultraviolet light and may lead to the development of malignancies. This trial aimed to evaluate efficacy and safety of ingenol disoxate gel (IngDsx, 0.018% for face/chest [FC]; 0.037% for scalp [S]), versus vehicle. METHODS: Four identical phase 3 trials in patients with AK on the full face/up to 250cm2 of chest or full balding scalp, with an initial 8-week period and 12-month follow-up, were conducted. FC and S trials were pooled for analysis. The primary endpoint was complete clearance at Week 8. RESULTS: Across trials, 616 patients were randomized to FC and 626 to S, with 410 and 420 assigned to receive IngDsx, respectively. In the FC and S trials, 25.9% and 24.5% of patients in the IngDsx group, respectively, achieved the primary endpoint. IngDsx was relatively well tolerated. During extended follow-up, there were more identified non-melanoma skin malignancies in the IngDsx group than vehicle group; HR: 2.38 (95% CI: 1.28, 4.41). CONCLUSION: Treatment with IngDsx was superior to vehicle on all clinical endpoints, patient-reported and cosmetic outcomes. During the 12-month follow-up, slightly increased skin malignancies in the treatment area were identified, potentially due to unintentional detection bias.


Assuntos
Fármacos Dermatológicos/administração & dosagem , Diterpenos/administração & dosagem , Ceratose Actínica/tratamento farmacológico , Administração Cutânea , Idoso , Fármacos Dermatológicos/efeitos adversos , Diterpenos/efeitos adversos , Face , Feminino , Géis , Humanos , Masculino , Pessoa de Meia-Idade , Couro Cabeludo , Neoplasias Cutâneas , Tórax
13.
Dermatol Surg ; 45(8): 1035-1041, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-30640783

RESUMO

BACKGROUND: There have been recent claims of overdiagnosis and unnecessary treatment in dermatology. One potential manifestation of overutilization would be providers who perform numerous biopsies per patient. OBJECTIVE: To identify the frequency of skin biopsy rate outliers. MATERIALS AND METHODS: Data on biopsy rates at the individual provider level were obtained from Medicare Provider Utilization and Payment Data Public Use Files. The total number of biopsies for each provider was obtained by summing the number of claimed biopsy services for each unique National Provider Identifier. The visit count for each provider was obtained by summing all evaluation and management services claimed. Provider biopsy rates were calculated by dividing the total number of biopsies associated with each National Provider Identifier by the corresponding visit count. RESULTS: The mean provider biopsy rate was 0.31 services per visit, or approximately 1 biopsy every 3 visits. Defining outliers as providers who averaged 3 or more biopsies per visit, there were 38 outliers out of 18,260 providers. Physicians had a lower mean biopsy rate than nonphysician clinicians (p = 1.70E-28). CONCLUSION: Contrary to claims, the authors' results do not indicate widespread overutilization of skin biopsy services.


Assuntos
Biópsia/estatística & dados numéricos , Padrões de Prática Médica/estatística & dados numéricos , Neoplasias Cutâneas/patologia , Revisão da Utilização de Recursos de Saúde , Idoso , Feminino , Humanos , Masculino , Medicare , Estados Unidos , Procedimentos Desnecessários/estatística & dados numéricos
15.
Dermatol Online J ; 25(5)2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-31220892

RESUMO

The Pigmented Lesion Assay (PLA, sensitivity 91-95%, specificity 69-91%, negative predictive value ?99%) is a commercially available, non-invasive gene expression test that helps dermatologists guide pigmented lesion management decisions and rule out melanoma. Earlier studies have demonstrated high clinical utility and no missed melanomas in a 3-6-month follow-up period. We undertook the current investigations to provide 12-month follow-up data on PLA(-) tests, and to further confirm utility. A 12-month chart review follow-up of 734 pigmented lesions that had negative PLA results from 5 US dermatology centers was performed. Thirteen of these lesions (1.8%) were biopsied in the follow-up period and submitted for histopathologic review. None of the lesions biopsied had a histopathologic diagnosis of melanoma. The test's utility was studied further in a registry (N=1575, 40 US dermatology offices, 62 participating providers), which demonstrated that 99.9% of PLA(-) lesions were clinically monitored, thereby avoiding a surgical procedure, and 96.5% of all PLA(+) lesions were appropriately biopsied, most commonly with a tangential shave. This long-term follow-up study confirms the PLA's high negative predictive value and high utility in helping guide the management of pigmented lesions to avoid unnecessary surgical procedures.


Assuntos
Melanoma/diagnóstico , Nevo Pigmentado/diagnóstico , Neoplasias Cutâneas/diagnóstico , Biópsia/estatística & dados numéricos , Diagnóstico Diferencial , Feminino , Seguimentos , Perfilação da Expressão Gênica , Testes Genéticos/métodos , Humanos , Masculino , Melanoma/genética , Melanoma/patologia , Pessoa de Meia-Idade , Padrões de Prática Médica/estatística & dados numéricos , Valor Preditivo dos Testes , Sistema de Registros , Sensibilidade e Especificidade , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/patologia , Estados Unidos
16.
J Cutan Pathol ; 45(1): 67-70, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29023848

RESUMO

Folliculocystic and collagen hamartoma (FCCH) of tuberous sclerosis is a rare entity described in 2012 by Torrelo et al. with only 8 cases described, predominantly in males. It presents since birth or early infancy and in the majority of cases is associated with tuberous sclerosis. The hamartoma presents as an exophytic plaque and has distinctive histopathological features including hair follicles, intact or ruptured epidermal cysts, and an increased number of collagen fibers extending to the subcutaneous tissue. Herein we present an additional case of this rare entity in an 18-year-old female who met clinical criteria for tuberous sclerosis. The patient had an exophytic mass in the left temporal area for many years and wanted surgical excision due to its cosmetic appearance. Histopathology of the surgical specimen showed a hamartomatous lesion with multiple large intact epidermal cysts, hairs and increased thickened collagen. The patient has followed up for 1 year after the excision, with no recurrence. Additionally, we provide a literature review of known cases of FCCH as well as its clinical and histopathological differential diagnosis.


Assuntos
Hamartoma/etiologia , Hamartoma/patologia , Dermatoses do Couro Cabeludo/etiologia , Dermatoses do Couro Cabeludo/patologia , Esclerose Tuberosa/complicações , Adolescente , Feminino , Humanos
17.
Lasers Surg Med ; 2018 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-29356026

RESUMO

OBJECTIVE: In dermatology, patient and physician adoption of light-emitting diode (LED) medical technology continues to grow as research indicates that LEDs may be used to treat skin conditions. The goal of this systematic review is to critically analyze published randomized controlled trials (RCTs) and provide evidence-based recommendations on the therapeutic uses of LEDs in dermatology based on published efficacy and safety data. METHODS: A systematic review of the published literature on the use of LED treatments for skin conditions was performed on September 13th 2017. RESULTS: Thirty-one original RCTs were suitable for review. CONCLUSIONS: LEDs represent an emerging modality to alter skin biology and change the paradigm of managing skin conditions. Acne vulgaris, herpes simplex and zoster, and acute wound healing received grade of recommendation B. Other skin conditions received grade of recommendation C or D. Limitations of some studies include small patient sample sizes (n < 20), absent blinding, no sham placebo, and varied treatment parameters. Due to few incidences of adverse events, affordability, and encouraging clinical results, we recommend that physicians use LEDs in clinical practice and researchers continue to explore the use of LEDs to treat skin conditions. Lasers Surg. Med. 9999:1-16, 2018. © 2018 The Authors. Lasers in Surgery and Medicine Published by Wiley Periodicals, Inc.

18.
Phys Rev Lett ; 119(23): 231102, 2017 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-29286684

RESUMO

The merger of binary neutron stars, or of a neutron star and a stellar-mass black hole, can result in the formation of a massive rotating torus around a spinning black hole. In addition to providing collimating media for γ-ray burst jets, unbound outflows from these disks are an important source of mass ejection and rapid neutron capture (r-process) nucleosynthesis. We present the first three-dimensional general-relativistic magnetohydrodynamic (GRMHD) simulations of neutrino-cooled accretion disks in neutron star mergers, including a realistic equation of state valid at low densities and temperatures, self-consistent evolution of the electron fraction, and neutrino cooling through an approximate leakage scheme. After initial magnetic field amplification by magnetic winding, we witness the vigorous onset of turbulence driven by the magnetorotational instability (MRI). The disk quickly reaches a balance between heating from MRI-driven turbulence and neutrino cooling, which regulates the midplane electron fraction to a low equilibrium value Y_{e}≈0.1. Over the 380-ms duration of the simulation, we find that a fraction ≈20% of the initial torus mass is unbound in powerful outflows with asymptotic velocities v≈0.1c and electron fractions Y_{e}≈0.1-0.25. Postprocessing the outflows through a nuclear reaction network shows the production of a robust second- and third-peak r process. Though broadly consistent with the results of previous axisymmetric hydrodynamical simulations, extrapolation of our results to late times suggests that the total ejecta mass from GRMHD disks is significantly higher. Our results provide strong evidence that postmerger disk outflows are an important site for the r process.

20.
J Am Acad Dermatol ; 75(5): 957-966.e2, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27473450

RESUMO

BACKGROUND: Accurate evaluation of basal cell carcinoma (BCC) in the United States was not possible before the 2011 release of BCC-specific International Classification of Diseases, Ninth Revision, Clinical Modification codes. OBJECTIVE: We sought to describe BCC (including locally advanced BCC [LABCC]) incidence/prevalence and the characteristics of patients in a commercially insured US population. METHODS: This retrospective cohort study used Truven Health MarketScan database insurance claims. Patients, aged 18 years or older with 2 or more BCC claims at least 30 days apart from October 1, 2011, to September 30, 2012, were continuously enrolled in medical and pharmacy benefits for 12 months before and after the index claim. A specific algorithm was used to classify patients with LABCC. RESULTS: A total of 56,987 patients with BCC were identified (39,035 incident cases; 17,952 prevalent cases). Age-adjusted BCC incidence and prevalence were 226.09 and 342.64 per 100,000 persons, respectively. These values project to 542,782 patients (incidence) and 822,593 patients (prevalence) in the 2012 US population. LABCC was uncommon (471 cases identified; projected US incidence and prevalence: 4399 and 7940 patients, respectively). LIMITATIONS: Use of medical claims data and retrospective analysis are limitations. CONCLUSION: In a study designed to distinguish patients with LABCC from the general BCC population based on BCC-specific International Classification of Diseases, Ninth Revision, Clinical Modification codes, 0.8% were found to have LABCC, the majority having pre-existing disease.


Assuntos
Carcinoma Basocelular/epidemiologia , Neoplasias Cutâneas/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma Basocelular/patologia , Bases de Dados Factuais , Feminino , Humanos , Incidência , Revisão da Utilização de Seguros , Classificação Internacional de Doenças , Masculino , Pessoa de Meia-Idade , Invasividade Neoplásica , Metástase Neoplásica , Estudos Retrospectivos , Neoplasias Cutâneas/patologia , Estados Unidos/epidemiologia , Adulto Jovem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA