Harvard University

About: Harvard University is a education organization based out in Cambridge, Massachusetts, United States. It is known for research contribution in the topics: Population & Cancer. The organization has 208150 authors who have published 530388 publications receiving 38152182 citations. The organization is also known as: Harvard & University of Harvard.

Nonsteroidal Anti-inflammatory Drugs and the Risk of Parkinson Disease

Abstract: Background Nonsteroidal anti-inflammatory drugs (NSAIDs) reduce dopaminergic neuron degeneration in animal models of Parkinson disease (PD). However, no epidemiological data have been available on NSAID use and the risk of PD. Objective To investigate prospectively whether the use of nonaspirin NSAIDs or aspirin is associated with decreased PD risk. Design, Settings, and Participants Prospective cohorts of 44 057 men and 98 845 women free of PD, stroke, or cancer (Health Professionals Follow-up Study, 1986-2000, and Nurses' Health Study, 1980-1998). Main Outcome Measure Newly diagnosed PD. Results We documented 415 incident PD cases (236 men and 179 women). Participants who reported regular use of nonaspirin NSAIDs at the beginning of the study had a lower risk of PD than nonregular users during the follow-up; the pooled multivariate relative risk was 0.55 (95% confidence interval, 0.32-0.96,P= .04). Compared with nonusers, a nonsignificantly lower risk of PD was also observed among men and women who took 2 or more tablets of aspirin per day (relative risk, 0.56; 95% confidence interval, 0.26-1.21). Conclusion These findings are consistent with the hypothesis that use of NSAIDs may delay or prevent the onset of PD.

A truncated activin receptor inhibits mesoderm induction and formation of axial structures in Xenopus embryos

Abstract: Activins can induce mesoderm in embryonic explants and have been proposed as the natural inducer in Xenopus. A mutant activin receptor that inhibits activin signalling is used to show that activin is required for the induction of mesoderm in vivo and the patterning of the embryonic body plan. Blocking the activin signal transduction pathway also reveals autonomous induction of a neural marker and unmasks a relationship between activin and fibroblast growth factor.

Programmable matter by folding

Abstract: Programmable matter is a material whose properties can be programmed to achieve specific shapes or stiffnesses upon command. This concept requires constituent elements to interact and rearrange intelligently in order to meet the goal. This paper considers achieving programmable sheets that can form themselves in different shapes autonomously by folding. Past approaches to creating transforming machines have been limited by the small feature sizes, the large number of components, and the associated complexity of communication among the units. We seek to mitigate these difficulties through the unique concept of self-folding origami with universal crease patterns. This approach exploits a single sheet composed of interconnected triangular sections. The sheet is able to fold into a set of predetermined shapes using embedded actuation. To implement this self-folding origami concept, we have developed a scalable end-to-end planning and fabrication process. Given a set of desired objects, the system computes an optimized design for a single sheet and multiple controllers to achieve each of the desired objects. The material, called programmable matter by folding, is an example of a system capable of achieving multiple shapes for multiple functions.

Guidelines for colonoscopy surveillance after polypectomy: A consensus update by the US Multi-Society Task Force on Colorectal Cancer and the American Cancer Society

Abstract: Adenomatous polyps are the most common neoplastic findings uncovered in people who undergo colorectal screening or have a diagnostic workup for symptoms. It was common practice in the 1970s for these patients to have annual follow-up surveillance examinations to detect additional new adenomas as well as missed synchronous adenomas. As a result of the National Polyp Study report in 1993, which demonstrated clearly in a randomized design that the first postpolypectomy examination could be deferred for 3 years, guidelines published by a gastrointestinal consortium in 1997 recommended that the first follow-up surveillance be 3 years after polypectomy for most patients. In 2003, these guidelines were updated, colonoscopy was recommended as the only follow-up examination, and stratification at baseline into lower and higher risk for subsequent adenomas was suggested. The 1997 and 2003 guidelines dealt with both screening and surveillance. However, it has become increasingly clear that postpolypectomy surveillance is now a large part of endoscopic practice, draining resources from screening and diagnosis. In addition, surveys have demonstrated that a large proportion of endoscopists are conducting surveillance examinations at shorter intervals than recommended in the guidelines. In the present paper, a careful analytic approach was designed addressing all evidence available in the literature to delineate predictors of advanced pathology, both cancer and advanced adenomas, so that patients can be more definitely stratified at their baseline colonoscopy into those at lower or increased risk for a subsequent advanced neoplasia. People at increased risk have either three or more adenomas, or high-grade dysplasia, or villous features, or an adenoma ≥1 cm in size. It is recommended that they have a 3-year follow-up colonoscopy. People at lower risk who have one or two small (<1 cm) tubular adenomas with no high-grade dysplasia can have a follow up in 5 to 10 years, whereas people with hyperplastic polyps only should have a 10-year follow up as average-risk people. Recent papers have reported a significant number of missed cancers by colonoscopy. However, high-quality baseline colonoscopy with excellent patient preparation and adequate withdrawal time should minimize this and reduce clinicians' concerns. These guidelines were developed jointly by the US Multi-Society Task Force on Colorectal Cancer and the American Cancer Society to provide a broader consensus and thereby increase utilization of the recommendations by endoscopists. Adoption of these guidelines nationally can have a dramatic impact on shifting available resources from intensive surveillance to screening. It has been shown that the first screening colonoscopy and polypectomy produces the greatest effects on reducing the incidence of colorectal cancer in patients with adenomatous polyps.