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51.
PCR with arbitrary primers: approach with care 总被引:13,自引:0,他引:13
W. C. Black IV 《Insect molecular biology》1993,2(1):1-6
New techniques have recently been described that employ the polymerase chain reaction (PCR) to amplify arbitrary regions of a genome using a single primer. The techniques reveal polymorphisms in insect taxa that lack allozyme variation and, for the first time, permit genetic polymorphisms to be rapidly analysed in small arthropods (e.g. mites, endoparasitic wasps). The methods have been used in identification of sub-species and cryptic species, and have applications in population genetics and genetic fingerprinting. They are fairly inexpensive, do not require the use of radioactivity, are relatively simple to learn and can easily be adapted to most laboratories. However, their application is not without technical problems and practical limitations. The purpose of this note is to indicate the critical factors to consider before launching into their use. We chiefly emphasize that most polymorphisms revealed by these methods segregate as dominant markers. Furthermore, application of these techniques requires extensive standardization and may not prove to be reproducible among various laboratories especially those employing different types of thermal cyclers. There are some unique features of these polymorphisms to consider when using them in genetic fingerprinting. In addition, because the techniques amplify arbitrary regions of genomes, similarly sized fragments amplified between two species may not be homologous. This argument and empirical observations suggest that PCR with arbitrary primers will have limited application in molecular systematics above the intraspecific level. 相似文献
52.
Kathy Murray MD Consulting Radiologist Adjunct Associate Professor of Radiology Marc Gosselin MD Associate Professor of Radiology Mark Anderson MD Radiology Resident Grant Berges Medical Student IV Eric Bachman MD Radiology Resident 《Seminars in Ultrasound, CT and MRI》2002,23(4):352-371
Radiologists rely on imaging patterns to arrive at a diagnosis. The different morphological patterns in the lungs are well known, but less emphasis has traditionally been placed on the pattern of distribution. This important feature greatly assists in the differential diagnosis regarding many pulmonary diseases and is the focus of this article. Chest radiographs often result in a narrow differential if one understands the regional differences and microenvironments within the lung and takes into consideration the ancillary imaging findings. High-resolution computed tomography offers additional information at the level of the secondary pulmonary lobule to fine-tune the distribution pattern and, consequently, the differential diagnosis. Disease distribution is often as important as the morphologic appearance of the disorder. This article will approach pulmonary diseases from the perspective of distribution patterns, highlighting the more common patterns. The goal of this review article is to give radiologists a conceptual framework that may be applied in their daily work environment. 相似文献
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Serologic screening of United States blood donors for Babesia microti using an investigational enzyme immunoassay 下载免费PDF全文
Andrew E. Levin Phillip C. Williamson Evan M. Bloch Joan Clifford Sherri Cyrus Beth H. Shaz Debra Kessler Jed Gorlin James L. Erwin Neil X. Krueger Greg V. Williams Oksana Penezina Sam R. Telford IV John A. Branda Peter J. Krause Gary P. Wormser Anna M. Schotthoefer Thomas R. Fritsche Michael P. Busch 《Transfusion》2016,56(7):1866-1874
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Ponnila S Samuel Jane P Pringle Nathaniel W James IV Susan J Fielding Kathleen M Fairfield 《International journal for equity in health》2009,8(1):30-5
Introduction
Minority women, particularly immigrants, have lower cancer screening rates than Caucasian women, but little else is known about cancer screening among immigrant women. Our objective was to assess breast, cervical, and colorectal cancer screening rates among immigrant women from Cambodia, Somalia, and Vietnam and explore screening barriers.Methods
We measured screening rates by systematic chart review (N = 100) and qualitatively explored screening barriers via face-to-face questionnaire (N = 15) of women aged 50–75 from Cambodia, Somalia, and Vietnam attending a general medicine clinic (Portland, Maine, USA).Results
Chart Review – Somali women were at higher risk of being unscreened for breast, cervical, and colorectal cancer compared with Cambodian and Vietnamese women. A longer period of US residency was associated with being screened for colorectal cancer. We observed a 7% (OR 1.07, 95% CI 1.01–1.13, p = 0.01) increase in the odds that a woman would undergo a fecal occult blood test for each additional year in the US, and a 39% increase in the odds of a woman being screened by colonoscopy or flexible sigmoidoscopy for every five years of additional US residence (OR 1.39, 95% CI 1.21–1.61, p = 0.02). We did not observe statistically significant relationships between odds of being screened by mammography, clinical breast exam or papanicolaou test according to years in the US. Questionnaire – We identified several barriers to breast, cervical, and colorectal cancer screening, including discomfort with exams conducted by male physicians.Discussion
Somali women were less likely to be screened for breast, cervical, and colorectal cancer than Cambodian and Vietnamese women in this population, and uptake of colorectal cancer screening is associated with years of residency in this country. Future efforts to improve equity in cancer screening among immigrants may require both provider and community education. 相似文献58.
59.
Katherine Semin Alvah C. Stahlnecker IV Kate Heelan Gregory A. Brown Brandon S. Shaw Ina Shaw 《Journal of Sports Science and Medicine》2008,7(4):455-460
A percentage of either measured or predicted maximum heart rate is commonly used to prescribe and measure exercise intensity. However, maximum heart rate in athletes may be greater during competition or training than during laboratory exercise testing. Thus, the aim of the present investigation was to determine if endurance-trained runners train and compete at or above laboratory measures of ''maximum'' heart rate. Maximum heart rates were measured utilising a treadmill graded exercise test (GXT) in a laboratory setting using 10 female and 10 male National Collegiate Athletic Association (NCAA) division 2 cross-country and distance event track athletes. Maximum training and competition heart rates were measured during a high-intensity interval training day (TR HR) and during competition (COMP HR) at an NCAA meet. TR HR (207 ± 5.0 b·min-1; means ± SEM) and COMP HR (206 ± 4 b·min-1) were significantly (p < 0.05) higher than maximum heart rates obtained during the GXT (194 ± 2 b·min-1). The heart rate at the ventilatory threshold measured in the laboratory occurred at 83.3 ± 2.5% of the heart rate at VO2 max with no differences between the men and women. However, the heart rate at the ventilatory threshold measured in the laboratory was only 77% of the maximal COMP HR or TR HR. In order to optimize training-induced adaptation, training intensity for NCAA division 2 distance event runners should not be based on laboratory assessment of maximum heart rate, but instead on maximum heart rate obtained either during training or during competition.
Key points
- A percentage of maximum heart rate is commonly used to prescribe and measure exercise intensity. However, maximum heart rate may be greater during competition or training than during laboratory exercise testing.
- Heart rates during training and competition were significantly higher than maximum heart rates obtained during laboratory exercise testing.
- To optimize training-induced adaptation, training intensity for NCAA division 2 distance event runners should not be based on laboratory assessment of maximum heart rate, but instead on maximum heart rate measure obtained either during training or during competition.
60.
Oliver J Bear Dont Walk IV Tony Sun Adler Perotte Nomie Elhadad 《J Am Med Inform Assoc》2021,28(9):1970
Clinical notes present a wealth of information for applications in the clinical domain, but heterogeneity across clinical institutions and settings presents challenges for their processing. The clinical natural language processing field has made strides in overcoming domain heterogeneity, while pretrained deep learning models present opportunities to transfer knowledge from one task to another. Pretrained models have performed well when transferred to new tasks; however, it is not well understood if these models generalize across differences in institutions and settings within the clinical domain. We explore if institution or setting specific pretraining is necessary for pretrained models to perform well when transferred to new tasks. We find no significant performance difference between models pretrained across institutions and settings, indicating that clinically pretrained models transfer well across such boundaries. Given a clinically pretrained model, clinical natural language processing researchers may forgo the time-consuming pretraining step without a significant performance drop. 相似文献