157 research outputs found
Can Doppler or contrast-enhanced ultrasound analysis add diagnostically important information about the nature of breast lesions?
OBJECTIVES: Despite evidence suggesting that Doppler ultrasonography can help to differentiate between benign and malignant breast lesions, it is rarely applied in clinical practice. The aim of this study was to determine whether certain vascular features of breast masses observed by duplex Doppler and color Doppler ultrasonography (before and/or after microbubble contrast injection) add information to the gray-scale analysis and support the Breast Imaging-Reporting and Data System (BI-RADS) classification. METHODS: Seventy solid lesions were prospectively evaluated with gray-scale ultrasonography, color Doppler ultrasonography, and contrast-enhanced ultrasonography. The morphological analysis and lesion vascularity were correlated with the histological results. RESULTS: Percutaneous core biopsies revealed that 25/70 (17.5%) lesions were malignant, while 45 were benign. Hypervascular lesions with tortuous and central vessels, a resistive index (RI)≥0.73 before contrast injection, and an RI≥0.75 after contrast injection were significantly predictive of malignancy (
Efeitos da substituição parcial do farelo de algodão para ovinos em confinamento: análise econômica
The objective of this study was to make an economic analysis of the results of partial replacement of cotton seed meal by Christinas bush ("mata-pasto") hay on sheep production in confinement at 0%, 5%, 10% and 15% levels. Costs, income and gross return were analysed. The results showed that all systems had a negative return. The best gross return was obtained when the Christinas bush has replaced the cotton seed meal in 5%.O objetivo deste estudo foi o de fazer uma análise econômica dos resultados da substituição parcial do farelo de algodão por feno de mata-pasto classificados a níveis de 0%, 5%, 10% e 15%, para ovinos em confinamento. Foram analisados os custos, receitas e margens de renda bruta. Os resultados mostraram que todos os sistemas tiveram margens de renda bruta negativas. A melhor margem foi obtida quando se substituiu o farelo de algodão por feno de mata-pasto em nível de 5%
Ultra-sonografia dúplex-Doppler na avaliação morfológica e hemodinâmica das artérias aorta e mesentérica cranial em cães
O conhecimento dos sinais normais ao ultra-som Doppler de cada vaso sanguíneo é fundamental na sua identificação. Existem poucos artigos na literatura veterinária que tratam do aspecto normal dos vasos abdominais nos cães. Com o objetivo de verificar a viabilidade técnica da aplicação do US-Doppler na avaliação da aorta abdominal e da artéria mesentérica cranial; vinte cães normais foram submetidos a este exame sem sedação. Foi descrito e avaliado o padrão de mapeamento dúplex-Doppler colorido destes vasos e os resultados comparados com aqueles descritos em literatura. Embora encontradas algumas limitações técnicas, verificamos que o US-Doppler pode ser aplicado com sucesso como meio não invasivo para a detecção de alterações no fluxo sanguíneo mesentérico em cães sem a necessidade de submete-los a contenção química.The knowledge of the normal Doppler signs of each blood vessel is important in their identification. There are few reports in veterinary literature that describe the normal aspect of abdominal blood vessels in dogs. The aim of this paper was verify technical viability of US Doppler use to assessment of the abdominal aorta and cranial mesenteric arteries; twenty clinically normal unsedated dogs were examinated. It was described and assessed characteristic duplex color Doppler spectrum of each blood vessel and the results were compared with that found in literature. Although some technical limitations were found, US Doppler could be successfully used as a noninvasive method to detect mesenteric blood flow changes in dogs without chemical contention
Keck Spectroscopy of 3<z<7 Faint Lyman Break Galaxies: The Importance of Nebular Emission in Understanding the Specific Star Formation Rate and Stellar Mass Density
The physical properties inferred from the SEDs of z>3 galaxies have been
influential in shaping our understanding of early galaxy formation and the role
galaxies may play in cosmic reionization. Of particular importance is the
stellar mass density at early times which represents the integral of earlier
star formation. An important puzzle arising from the measurements so far
reported is that the specific star formation rates (sSFR) evolve far less
rapidly than expected in most theoretical models. Yet the observations
underpinning these results remain very uncertain, owing in part to the possible
contamination of rest-optical broadband light from strong nebular emission
lines. To quantify the contribution of nebular emission to broad-band fluxes,
we investigate the SEDs of 92 spectroscopically-confirmed galaxies in the
redshift range 3.8<z<5.0 chosen because the H-alpha line lies within the
Spitzer/IRAC 3.6 um filter. We demonstrate that the 3.6 um flux is
systematically in excess of that expected from stellar continuum, which we
derive by fitting the SED with population synthesis models. No such excess is
seen in a control sample at 3.1<z<3.6 in which there is no nebular
contamination in the IRAC filters. From the distribution of our 3.6 um flux
excesses, we derive an H-alpha equivalent width (EW) distribution. The mean
rest-frame H-alpha EW we infer at 3.8<z<5.0 (270 A) indicates that nebular
emission contributes at least 30% of the 3.6 um flux. Via our
empirically-derived EW distribution we correct the available stellar mass
densities and show that the sSFR evolves more rapidly at z>4 than previously
thought, supporting up to a 5x increase between z~2 and 7. Such a trend is much
closer to theoretical expectations. Given our findings, we discuss the
prospects for verifying quantitatively the nebular emission line strengths
prior to the launch of the James Webb Space Telescope.Comment: 16 pages, 9 figures, submitted to Ap
Mammography-based screening program: preliminary results from a first 2-year round in a Brazilian region using mobile and fixed units
RLH, TBS and ALF made substantial contributions to the conception and
design of the article, the acquisition, analysis and interpretation of the data,
and drafting of the article. ECM, JSCM and NB made substantial
contributions to the conception and design of the study.Background: Breast cancer is the most frequently diagnosed cancer and the leading cause of cancer deaths
among women worldwide. The use of mobile mammography units to offer screening to women living in remote
areas is a rational strategy to increase the number of women examined. This study aimed to evaluate results from
the first 2 years of a government-organized mammography screening program implemented with a mobile unit
(MU) and a fixed unit (FU) in a rural county in Brazil. The program offered breast cancer screening to women living
in Barretos and the surrounding area.
Methods: Based on epidemiologic data, 54 238 women, aged 40 to 69 years, were eligible for breast cancer
screening. The study included women examined from April 1, 2003 to March 31, 2005. The chi-square test and
Bonferroni correction analyses were used to evaluate the frequencies of tumors and the importance of clinical
parameters and tumor characteristics. Significance was set at p < 0.05.
Results: Overall, 17 964 women underwent mammography. This represented 33.1% of eligible women in the area.
A mean of 18.6 and 26.3 women per day were examined in the FU and MU, respectively. Seventy six patients were
diagnosed with breast cancer (41 (54%) in the MU). This represented 4.2 cases of breast cancer per 1000
examinations. The number of cancers detected was significantly higher in women aged 60 to 69 years than in
those aged 50 to 59 years (p < 0.001) or 40 to 49 years (p < 0.001). No difference was observed between women
aged 40 to 49 years and those aged 50 to 59 years (p = 0.164). The proportion of tumors in the early (EC 0 and EC
I) and advanced (CS III and CS IV) stages of development were 43.4% and 15.8%, respectively.
Conclusions: Preliminary results indicate that this mammography screening program is feasible for implementation
in a rural Brazilian territory and favor program continuation
Avaliação ultra-sonográfica e ao Doppler dos TIPS (anastomose portossistêmica intra-hepática transjugular)
Moderately hypofractionated post-operative radiation therapy for breast cancer: Preferences amongst radiation oncologists from countries in Latin America and the Caribbean
Background: The safety and effectiveness of moderately hypofractionated post-operative radiation therapy for breast cancer were demonstrated by several trials. This study aimed to evaluate the current patterns of practice and prescription preference about moderately hypofractionated post-operative radiation therapy to assess possible aspects that affect the decision-making process regarding the use of fractionation in breast cancer patients in Latin America and the Caribbean (LAC). We also aimed to identify factors that can restrain the utilization of moderately hypofractionated post-operative radiation therapy for breast cancer.
Materials an methods: Radiation oncologists from LAC were invited to contribute to this study. A 38-question survey was used to evaluate their opinions.
Results: A total of 173 radiation oncologists from 13 countries answered the questionnaire. The majority of respondents (84.9%) preferred moderately hypofractionated post-operative radiation therapy as their first choice in cases of whole breast irradiation. Whole breast plus regional nodal irradiation, post-mastectomy (chest wall and regional nodal irradiation) without reconstruction, and post-mastectomy (chest wall and regional node irradiation) with reconstruction hypofractionated post-operative radiation therapy was preferred by 72.2% 71.1%, and 53.7% of respondents, respectively. Breast cancer stage, and flap-based breast reconstruction were the factors associated with absolute contraindications for the use of hypofractionated schedules.
Conclusion: Even though moderately hypofractionated post-operative radiation therapy for breast cancer is considered a new standard to the vast majority of the patients, its unrestricted application in clinical practice across LAC still faces reluctance
Observations of Ly Emitters at High Redshift
In this series of lectures, I review our observational understanding of
high- Ly emitters (LAEs) and relevant scientific topics. Since the
discovery of LAEs in the late 1990s, more than ten (one) thousand(s) of LAEs
have been identified photometrically (spectroscopically) at to . These large samples of LAEs are useful to address two major astrophysical
issues, galaxy formation and cosmic reionization. Statistical studies have
revealed the general picture of LAEs' physical properties: young stellar
populations, remarkable luminosity function evolutions, compact morphologies,
highly ionized inter-stellar media (ISM) with low metal/dust contents, low
masses of dark-matter halos. Typical LAEs represent low-mass high- galaxies,
high- analogs of dwarf galaxies, some of which are thought to be candidates
of population III galaxies. These observational studies have also pinpointed
rare bright Ly sources extended over kpc, dubbed
Ly blobs, whose physical origins are under debate. LAEs are used as
probes of cosmic reionization history through the Ly damping wing
absorption given by the neutral hydrogen of the inter-galactic medium (IGM),
which complement the cosmic microwave background radiation and 21cm
observations. The low-mass and highly-ionized population of LAEs can be major
sources of cosmic reionization. The budget of ionizing photons for cosmic
reionization has been constrained, although there remain large observational
uncertainties in the parameters. Beyond galaxy formation and cosmic
reionization, several new usages of LAEs for science frontiers have been
suggested such as the distribution of {\sc Hi} gas in the circum-galactic
medium and filaments of large-scale structures. On-going programs and future
telescope projects, such as JWST, ELTs, and SKA, will push the horizons of the
science frontiers.Comment: Lecture notes for `Lyman-alpha as an Astrophysical and Cosmological
Tool', Saas-Fee Advanced Course 46. Verhamme, A., North, P., Cantalupo, S., &
Atek, H. (eds.) --- 147 pages, 103 figures. Abstract abridged. Link to the
lecture program including the video recording and ppt files :
https://obswww.unige.ch/Courses/saas-fee-2016/program.cg
- …