Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 6 de 6
Filtrar
1.
Sci Data ; 10(1): 73, 2023 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-36739456

RESUMO

Since the early 2000s, sea ice has experienced an increased rate of decline in thickness, extent and age. This new regime, coined the 'New Arctic', is accompanied by a reshuffling of energy flows at the surface. Understanding of the magnitude and nature of this reshuffling and the feedbacks therein remains limited. A novel database is presented that combines satellite observations, model output, and reanalysis data with sea ice parcel drift tracks in a Lagrangian framework. This dataset consists of daily time series of sea ice parcel locations, sea ice and snow conditions, and atmospheric states, including remotely sensed surface energy budget terms. Additionally, flags indicate when sea ice parcels travel within cyclones, recording cyclone intensity and distance from the cyclone center. The quality of the ice parcel database was evaluated by comparison with sea ice mass balance buoys and correlations are high, which highlights the reliability of this database in capturing the seasonal changes and evolution of sea ice. This database has multiple applications for the scientific community; it can be used to study the processes that influence individual sea ice parcel time series, or to explore generalized summary statistics and trends across the Arctic.

2.
J Geophys Res Oceans ; 125(10): e2019JC015913, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33133995

RESUMO

A Lagrangian snow-evolution model (SnowModel-LG) was used to produce daily, pan-Arctic, snow-on-sea-ice, snow property distributions on a 25 × 25-km grid, from 1 August 1980 through 31 July 2018 (38 years). The model was forced with NASA's Modern Era Retrospective-Analysis for Research and Applications-Version 2 (MERRA-2) and European Centre for Medium-Range Weather Forecasts (ECMWF) ReAnalysis-5th Generation (ERA5) atmospheric reanalyses, and National Snow and Ice Data Center (NSIDC) sea ice parcel concentration and trajectory data sets (approximately 61,000, 14 × 14-km parcels). The simulations performed full surface and internal energy and mass balances within a multilayer snowpack evolution system. Processes and features accounted for included rainfall, snowfall, sublimation from static-surfaces and blowing-snow, snow melt, snow density evolution, snow temperature profiles, energy and mass transfers within the snowpack, superimposed ice, and ice dynamics. The simulations produced horizontal snow spatial structures that likely exist in the natural system but have not been revealed in previous studies spanning these spatial and temporal domains. Blowing-snow sublimation made a significant contribution to the snowpack mass budget. The superimposed ice layer was minimal and decreased over the last four decades. Snow carryover to the next accumulation season was minimal and sensitive to the melt-season atmospheric forcing (e.g., the average summer melt period was 3 weeks or 50% longer with ERA5 forcing than MERRA-2 forcing). Observed ice dynamics controlled the ice parcel age (in days), and ice age exerted a first-order control on snow property evolution.

3.
Hum Pathol ; 35(7): 798-807, 2004 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15257542

RESUMO

Advances in the detection of carcinoma of the prostate during the last 15 years have accounted for a sharp increase and then an abrupt decrease in the incidence of the disease. A more recent decline in its mortality rates has been variously interpreted as either the success of early detection and improved treatment or lead-time bias. The recently reported Prostate Cancer Prevention Trial had an overall detection rate that approached the 30%-40% prevalence rates reported in autopsy series in which men died of other causes. However, the prognostic information that can be obtained from prostate cancer found on biopsy is limited. Three-dimensional computer modeling is one technique that allows multiple studies on "immortal" prostates to test methods of biopsy sampling accuracy and to assist in the determination of the disease's severity. Computer modeling can assess detection rates and assesses tumor multifocality and heterogeneity. It can provide a more accurate representation of tumor volume, aiding in therapeutic decision making, and can assess sampling errors of various biopsy methods. It has been shown to be superior to wire-frame technique by immortalizing the original shape and dimensions of the surgically excised prostate gland. Moreover, our 3-dimensional computer modeling system improves upon other systems: It is more than a simple extension of the planimetric technique, and it is able to demarcate clearly the boundaries of Gleason grades just 1 grade apart.


Assuntos
Adenocarcinoma/patologia , Imageamento Tridimensional , Modelos Anatômicos , Neoplasias da Próstata/patologia , Adenocarcinoma/classificação , Humanos , Masculino , Neoplasias da Próstata/classificação
4.
Am J Respir Crit Care Med ; 174(6): 654-8, 2006 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-16799077

RESUMO

BACKGROUND: Usual interstitial pneumonia (UIP), the pathologic correlate of idiopathic pulmonary fibrosis, contains characteristic discrete areas of fibroblasts, myofibroblasts, and newly formed collagen, termed "fibroblast foci." These lesions are argued to represent isolated sites of recurrent acute lung injury and suggested to be the mechanism of disease progression. We hypothesized that, rather than isolated, these lesions are part of an organized neoplasm. METHODS: Morphometric analysis of pentachrome-stained histologic sections of UIP was performed. Using point-counting technique on serial sections, fibroblast foci, arteries, and macrophage clusters were identified and we determined their individual "connectiveness" by estimating the Euler number. Two-dimensional micrographs were collated into a three-dimensional array from which a visual three-dimensional reconstruction could be constructed. Clonality analysis was performed using human androgen receptor gene methylation assay. RESULTS: Blood vessels show significant connectivity with a Euler number of 2, whereas macrophage clusters exhibited no connectivity. The fibroblast foci showed a high level of interconnection with Euler numbers ranging from 19 to 39. The computer generated three-dimensional models provide a visual confirmation of this connectiveness. Human androgen receptor gene methylation assay analysis of the foci showed balanced methylation consistent with polyclonality. CONCLUSIONS: The fibroblast foci of UIP are the leading edge of a complex reticulum that is highly interconnected and extends from the pleura into the underlying parenchyma. It is a reactive, rather than a malignant, process.


Assuntos
Fibroblastos/ultraestrutura , Pulmão/patologia , Síndrome do Desconforto Respiratório/patologia , Progressão da Doença , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Técnicas In Vitro , Doenças Pulmonares Intersticiais/complicações , Doenças Pulmonares Intersticiais/patologia , Fotomicrografia , Estudos Prospectivos , Síndrome do Desconforto Respiratório/etiologia
5.
BJU Int ; 96(7): 999-1004, 2005 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16225516

RESUMO

OBJECTIVE: To identify the precise location of prostate cancer within the gland and thus possibly permit more aggressive therapy of the lesion, while potentially sparing the noncancerous gland from ablative therapy. MATERIALS AND METHODS: Three-dimensional "solid" computer models were reconstructed for 86 autopsy specimens and 20 stage T1c radical prostatectomy specimens. Transperineal biopsies were simulated for grid sizes of 5-mm (method A) and 10-mm (method B) with an 18 G, 23-mm long biopsy needle. One or two biopsies per grid point were obtained for a total of 12-108 biopsies, depending on the size of the prostate. Clinically threatening cancers were defined as having volumes of > or = 0.5 mL or Gleason sum > or = 7. RESULTS: Method A detected significantly more carcinomas than method B in both the autopsy and prostatectomy specimens (autopsy, 72 vs 51; prostatectomy, 50 vs 32, both P < 0.001). Method A also detected more clinically threatening cancers found at autopsy (38/40 vs 31/40, P = 0.008). Among autopsy patients with negative sextant biopsies whose disease was localized to one side, method A detected 72% and method B detected 29-43% (P < 0.001). CONCLUSIONS: The results of this computer simulation show that 5- and 10-mm grid biopsies detect three-quarters and a third, respectively, at autopsy, of patients with the disease localized to one side of the prostate, which may be useful when planning highly selective ablative treatments in the future.


Assuntos
Processamento de Imagem Assistida por Computador , Imageamento Tridimensional , Neoplasias da Próstata/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Autopsia , Biópsia/métodos , Humanos , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Prostatectomia , Neoplasias da Próstata/cirurgia , Sensibilidade e Especificidade
6.
Prostate ; 57(2): 118-28, 2003 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-12949935

RESUMO

BACKGROUND: The purpose of this study was to determine, whether a modified fan-shaped biopsy (MFSB) technique which utilizes six laterally directed biopsies would lead to higher detection rates of clinically threatening prostatic carcinoma than the six random systematic core biopsy (SRSCB) method. METHODS: We reconstructed 3-dimensional solid computer models of 86 autopsy prostates and 40 radical prostatatectomy specimens. Simulations of SRSCB and MFSB were then performed using the same biopsy sites except that the biopsy probe was rotated 45 degrees toward posterolateral peripheral zone for MFSB. When the Gleason sum was less than 7, clinically threatening cancers were defined as having a tumor volume > or =0.25 cc or > or =0.5 cc. RESULTS: When the cut off volume was 0.25 cc, MFSB detected significantly more threatening carcinomas in autopsy prostates than did SRSCB (P < 0.0082). This was also true for the surgical prostates (P < 0.0047) as well as for a sub-group of non-palpable carcinomas (P < 0.0047). When the cut off volume was increased to 0.5 cc, MFSB detected significantly more threatening carcinomas in the radical series (P < 0.0047) and for the non-palpable carcinomas (P < 0.0082), but not in the autopsy series. CONCLUSIONS: The MFSB technique, which utilizes laterally directed biopsies, appears to be an effective approach to improve the detection of clinically threatening prostatic carcinoma.


Assuntos
Biópsia/métodos , Carcinoma/patologia , Neoplasias da Próstata/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Biópsia/normas , Simulação por Computador , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Modelos Anatômicos , Prognóstico
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA