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1.
Phys Rev Lett ; 114(11): 111302, 2015 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-25839256

RESUMO

While the standard model of particle physics does not include free particles with fractional charge, experimental searches have not ruled out their existence. We report results from the Cryogenic Dark Matter Search (CDMS II) experiment that give the first direct-detection limits for cosmogenically produced relativistic particles with electric charge lower than e/6. A search for tracks in the six stacked detectors of each of two of the CDMS II towers finds no candidates, thereby excluding new parameter space for particles with electric charges between e/6 and e/200.

2.
Phys Rev Lett ; 112(4): 041302, 2014 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-24580434

RESUMO

SuperCDMS is an experiment designed to directly detect weakly interacting massive particles (WIMPs), a favored candidate for dark matter ubiquitous in the Universe. In this Letter, we present WIMP-search results using a calorimetric technique we call CDMSlite, which relies on voltage-assisted Luke-Neganov amplification of the ionization energy deposited by particle interactions. The data were collected with a single 0.6 kg germanium detector running for ten live days at the Soudan Underground Laboratory. A low energy threshold of 170 eVee (electron equivalent) was obtained, which allows us to constrain new WIMP-nucleon spin-independent parameter space for WIMP masses below 6 GeV/c2.

3.
Phys Rev Lett ; 106(13): 131302, 2011 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-21517371

RESUMO

We report results from a reanalysis of data from the Cryogenic Dark Matter Search (CDMS II) experiment at the Soudan Underground Laboratory. Data taken between October 2006 and September 2008 using eight germanium detectors are reanalyzed with a lowered, 2 keV recoil-energy threshold, to give increased sensitivity to interactions from weakly interacting massive particles (WIMPs) with masses below ∼10 GeV/c(2). This analysis provides stronger constraints than previous CDMS II results for WIMP masses below 9 GeV/c(2) and excludes parameter space associated with possible low-mass WIMP signals from the DAMA/LIBRA and CoGeNT experiments.

4.
Vaccine ; 38(5): 979-992, 2020 01 29.
Artigo em Inglês | MEDLINE | ID: mdl-31787412

RESUMO

After many decades of vaccination, measles epidemiology varies greatly between and within countries. National immunization programs are therefore encouraged to conduct regular situation analyses and to leverage models to adapt interventions to local needs. Here, we review applications of models to develop locally tailored interventions to support control and elimination efforts. In general, statistical and semi-mechanistic transmission models can be used to synthesize information from vaccination coverage, measles incidence, demographic, and/or serological data, offering a means to estimate the spatial and age-specific distribution of measles susceptibility. These estimates complete the picture provided by vaccination coverage alone, by accounting for natural immunity. Dynamic transmission models can then be used to evaluate the relative impact of candidate interventions for measles control and elimination and the expected future epidemiology. In most countries, models predict substantial numbers of susceptible individuals outside the age range of routine vaccination, which affects outbreak risk and necessitates additional intervention to achieve elimination. More effective use of models to inform both vaccination program planning and evaluation requires the development of training to enhance broader understanding of models and where feasible, building capacity for modelling in-country, pipelines for rapid evaluation of model predictions using surveillance data, and clear protocols for incorporating model results into decision-making.


Assuntos
Países em Desenvolvimento , Erradicação de Doenças , Programas de Imunização , Sarampo , Humanos , Sarampo/epidemiologia , Sarampo/prevenção & controle , Vacina contra Sarampo/administração & dosagem , Modelos Teóricos , Cobertura Vacinal
5.
Phys Rev Lett ; 103(14): 141802, 2009 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-19905561

RESUMO

We report on the first axion search results from the Cryogenic Dark Matter Search (CDMS) experiment at the Soudan Underground Laboratory. An energy threshold of 2 keV for electron-recoil events allows a search for possible solar axion conversion into photons or local galactic axion conversion into electrons in the germanium crystal detectors. The solar axion search sets an upper limit on the Primakov coupling g(agammagamma) of 2.4x10(-9) GeV-1 at the 95% confidence level for an axion mass less than 0.1 keV/c2. This limit benefits from the first precise measurement of the absolute crystal plane orientations in this type of experiment. The galactic axion search analysis sets a world-leading experimental upper limit on the axioelectric coupling g(aee) of 1.4x10(-12) at the 90% confidence level for an axion mass of 2.5 keV/c2.

6.
Invest Radiol ; 23(10): 725-8, 1988 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-3192395

RESUMO

The detectability of malignant tumor-derived microcalcifications with conventional mammography was compared to that with digital images (2000 X 2510 pixels by 10 bits) derived from a storage phosphor-based digital radiography system capable of 5 line pair/mm resolution at identical exposure factors (30 kVp, 250 mAs, 65 cm film-focus distance). Microcalcifications (50-800 microns in diameter) were randomly superimposed on a preserved human breast specimen. ROC analysis based on 480 observations made by four readers indicated that the ability to detect the calcifications with digital images (ROC area = 0.871 +/- 0.066) was equivalent to conventional mammography (ROC area = 0.866 +/- 0.075) despite lower spatial resolution. With digital mammography, 62% of all clusters were correctly localized, but only 23.6% of the individual calcifications were counted. With conventional mammography 61% of all clusters were correctly localized, but significantly more of the individual calcifications (31.5%) were counted.


Assuntos
Doenças Mamárias/diagnóstico por imagem , Neoplasias da Mama/complicações , Calcinose/diagnóstico por imagem , Mamografia , Intensificação de Imagem Radiográfica , Doenças Mamárias/etiologia , Neoplasias da Mama/diagnóstico por imagem , Calcinose/etiologia , Feminino , Humanos , Técnicas In Vitro , Modelos Estruturais , Curva ROC
7.
Invest Radiol ; 24(9): 643-6, 1989 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-2807816

RESUMO

Fine linear structures represent a severe test of the minimum spatial resolution that is needed for digital chest imaging. We studied the comparative observer performance of storage phosphor digital imaging (1760 X 2140 pixel matrix, 10 bits deep), and conventional radiography (Lanex medium screen, Ortho C film) in the detection of simulated fine pulmonary lines superimposed on the normal chest when exposure factors were identical (20mR skin entrance dose at 141 kVp). Receiver operating characteristics analysis of 2160 observations by six readers found that high frequency edge-enhanced digital images (ROC area: 0.78 +/- 0.06) performed better than unenhanced digital images (ROC area: 0.70 +/- 0.07) (P less than 0.01 for paired t-test), and that edge enhanced digital images performed on a par with conventional radiography (ROC area: 0.78 +/- 0.09). We conclude that for the detection of fine linear structures, storage phosphor digital images can perform on a par with higher resolution conventional chest radiographs when a high frequency edge-enhancement algorithm is employed.


Assuntos
Intensificação de Imagem Radiográfica/normas , Radiografia Torácica/normas , Adulto , Humanos , Masculino , Curva ROC , Radiografia Torácica/métodos
8.
Invest Radiol ; 25(6): 645-50, 1990 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-2354926

RESUMO

Digital storage phosphor radiography (SR) has a wide dynamic range and unique postprocessing capabilities that may improve the performance of screening studies for asbestos-related pleural disease compared with conventional film radiography (FR). In a group of 32 asbestos-exposed and nine control subjects with established pleural data, we compared the screening performance of FR and SR obtained with a single isoexposure, dual-energy technique (system resolution 0.2 mm, 10 bits). Performance was evaluated for 7320 observations by eight readers using a paired t test (P less than .02 with Bonferroni correction) of averaged receiver operating characteristic curve (ROC) areas (Az +/- standard error). We found that SR alone and SR supplemented by dual-energy soft-tissue and calcium images (SRde) were superior to FR in the overall detection of pleural abnormalities (Az = 0.90 +/- 0.01, 0.90 +/- 0.01, and 0.88 +/- 0.01, respectively). In the specific detection of pleural calcification, SRde was superior to FR (Az = 0.91 +/- 0.01 and 0.87 +/- 0.01, respectively; P less than 0.01). Analysis of variance indicated that SRde most closely reproduced an established pleural score based on the International Labor Organization (ILO) classification of the pneumoconioses (P less than 0.05, Scheffé's multiple comparison test). We conclude that isodose SR performs at least as well as FR in screening for asbestos-related pleural disease. SR supplemented by dual-energy images might improve the specific detection of pleural calcifications compared with FR.


Assuntos
Asbestose/complicações , Programas de Rastreamento/métodos , Doenças Pleurais/prevenção & controle , Intensificação de Imagem Radiográfica/métodos , Asbestose/diagnóstico por imagem , Humanos , Masculino , Pessoa de Meia-Idade , Doenças Pleurais/diagnóstico por imagem , Doenças Pleurais/etiologia
9.
Arch Surg ; 125(5): 601-4, 1990 May.
Artigo em Inglês | MEDLINE | ID: mdl-2331218

RESUMO

We reviewed 30 cases of breast cancer originally diagnosed as medullary carcinoma during a 10-year period. Of the 30, only 9 proved to be "typical medullary carcinoma" with the associated favorable prognosis. Seven of the remaining 21 cancers were reclassified as "atypical medullary carcinoma," and the remaining 14 were nonmedullary cancers. Overdiagnosis of medullary carcinoma could lead to inappropriately conservative therapy, since medullary carcinoma is a prognostically favorable neoplasm. Those involved with diagnosis and treatment of patients with breast cancer should be aware of this potential problem.


Assuntos
Neoplasias da Mama/patologia , Carcinoma/patologia , Adulto , Idoso , Neoplasias da Mama/classificação , Neoplasias da Mama/epidemiologia , Carcinoma/classificação , Carcinoma/epidemiologia , Feminino , Humanos , Massachusetts/epidemiologia , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos
10.
Acad Radiol ; 3(2): 115-20, 1996 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-8796651

RESUMO

RATIONALE AND OBJECTIVES: We examined the role of computed tomography (CT) in breast imaging, especially in guiding needle localization procedures. METHODS: We reviewed our institution's breast imaging database, from 1978 to 1994, for procedures in which CT scanning was used. Twenty-four CT-guided needle localizations were identified. Medical records, mammograms, CT scans, and pathology reports were reviewed for all patients. RESULTS: Twenty-four needle localizations were performed on 22 female patients. The average size of the lesions localized was 12 mm. The most common reason for CT scanning was the inability to image a suspicious density by conventional mammography on two orthogonal views. Nine malignant and 15 benign lesions were localized under CT guidance. One patient developed a postoperative hematoma. No other complications occurred. CONCLUSION: CT-guided breast localization is a reliable technique that may be used to define selected breast lesions that are difficult to triangulate or localize by conventional two-view mammography.


Assuntos
Biópsia por Agulha , Mama/patologia , Radiografia Intervencionista , Tomografia Computadorizada por Raios X , Idoso , Idoso de 80 Anos ou mais , Biópsia por Agulha/métodos , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/diagnóstico por imagem , Feminino , Humanos , Mamografia , Pessoa de Meia-Idade , Palpação
11.
Science ; 327(5973): 1619-21, 2010 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-20150446

RESUMO

Astrophysical observations indicate that dark matter constitutes most of the mass in our universe, but its nature remains unknown. Over the past decade, the Cryogenic Dark Matter Search (CDMS II) experiment has provided world-leading sensitivity for the direct detection of weakly interacting massive particle (WIMP) dark matter. The final exposure of our low-temperature germanium particle detectors at the Soudan Underground Laboratory yielded two candidate events, with an expected background of 0.9 +/- 0.2 events. This is not statistically significant evidence for a WIMP signal. The combined CDMS II data place the strongest constraints on the WIMP-nucleon spin-independent scattering cross section for a wide range of WIMP masses and exclude new parameter space in inelastic dark matter models.

13.
Phys Rev Lett ; 102(1): 011301, 2009 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-19257177

RESUMO

We report results from the Cryogenic Dark Matter Search at the Soudan Underground Laboratory (CDMS II) featuring the full complement of 30 detectors. A blind analysis of data taken between October 2006 and July 2007 sets an upper limit on the weakly interacting massive particle (WIMP) nucleon spin-independent cross section of 6.6x10;{-44} cm;{2} (4.6x10;{-44} cm;{2} when combined with previous CDMS II data) at the 90% confidence level for a WIMP mass of 60 GeV/c;{2}. This achieves the best sensitivity for dark matter WIMPs with masses above 44 GeV/c;{2}, and significantly restricts the parameter space for some favored supersymmetric models.

14.
J Ultrasound Med ; 5(9): 503-5, 1986 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-3531543

RESUMO

In order to help clarify the clinical problem of the postmenopausal woman with an adnexal cyst, 13 patients with sonographically detected relatively simple adnexal cysts were reviewed. Only one patient had a "borderline" malignancy; the remaining cysts were all benign. The 8 per cent malignancy rate in this small series suggests that the simple postmenopausal adnexal cyst may not necessarily be an ominous finding.


Assuntos
Doenças dos Anexos/diagnóstico , Cistos/diagnóstico , Menopausa , Ultrassonografia , Idoso , Idoso de 80 Anos ou mais , Cistadenoma/diagnóstico , Feminino , Humanos , Pessoa de Meia-Idade
15.
Appl Opt ; 34(34): 8074, 1995 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-21068916

RESUMO

A device is described with which the optical activity of crystalline materials under stress can be measured. The sample is not moved, but a three-axis rotation is possible.

16.
J Ultrasound Med ; 5(1): 9-11, 1986 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-3511280

RESUMO

The pelvic sonograms of 30 postmenopausal women who demonstrated no pathology in 8-18 months of clinical follow-up were reviewed. In 19 cases both ovaries were visualized. Only one ovary was seen in three patients and neither ovary identified in eight patients. Ovarian volumes were all less than or equal to 2.5 cm3. The authors suggest that, contrary to previous experience, a large proportion of normal postmenopausal ovaries can be depicted sonographically. Further data are necessary before definite normal volumes are known but sonography may be useful to screen patients to help detect early ovarian carcinoma.


Assuntos
Menopausa , Ovário/anatomia & histologia , Ultrassonografia , Idoso , Feminino , Humanos , Pessoa de Meia-Idade , Neoplasias Ovarianas/diagnóstico , Valores de Referência
17.
Radiology ; 163(2): 577-9, 1987 May.
Artigo em Inglês | MEDLINE | ID: mdl-3562843

RESUMO

The preoperative triangulation and localization of some occult breast lesions can be complicated if the lesion is located deep in the breast. Based on the authors' experience of 1,400 localization procedures, standard breast positions were modified to help locate lesions that were difficult to see in two projections. Standard compression plates were also modified, allowing placement of fenestrations over deep lesions--especially those in the axillary tail of the breast--to facilitate safe, accurate localization.


Assuntos
Neoplasias da Mama/diagnóstico por imagem , Mastectomia/métodos , Neoplasias da Mama/cirurgia , Feminino , Humanos , Mamografia/métodos , Tecnologia Radiológica
18.
J Ultrasound Med ; 5(11): 647-9, 1986 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-3537335

RESUMO

An endometrial collection in a postmenopausal woman is abnormal. Its potential for heralding pelvic malignancy has been emphasized. Although malignancy must always be excluded, the authors' experience with a large outpatient population indicates that benign causes of uterine fluid collections may be more common than previously reported. During a 14-month period eight postmenopausal women with endometrial fluid collections were identified in the outpatient ultrasound department of the Massachusetts General Hospital. Seventy-five per cent of these were secondary to benign processes.


Assuntos
Líquidos Corporais/análise , Endométrio/patologia , Menopausa , Ultrassonografia , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Pessoa de Meia-Idade , Neoplasias Pélvicas/diagnóstico
19.
AJR Am J Roentgenol ; 148(3): 525-6, 1987 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-3492880

RESUMO

We studied the relationship between the radiographic density of the breast as measured by parenchymal pattern vs age, breast size, thickness after compression, and compressibility. Two hundred consecutive women were evaluated. None of the three parameters or the patient's age correlated with the degree of radiographic density. Although more older women had lucent parenchyma, 37% of women more than 50 years of age had dense patterns. Thus, these factors cannot be used to predict radiographic density. Phototiming is required to maintain image quality, and only a test exposure can accurately predict breast density.


Assuntos
Mama/anatomia & histologia , Mamografia/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Pessoa de Meia-Idade
20.
Radiology ; 173(3): 873-4, 1989 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-2813799

RESUMO

Special compression views of the breast were used to detect suspect lesions in eight women who had undergone augmentation mammoplasty. Hook-wire localization with the use of these views proved safe and accurate for preoperative localization in these women, one of whom had a very small cancer.


Assuntos
Neoplasias da Mama/diagnóstico por imagem , Mama/cirurgia , Mamografia/métodos , Próteses e Implantes , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/cirurgia , Feminino , Humanos , Palpação
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