首页期刊导航|Proceedings of the National Academy of Sciences of the United States of America
期刊信息/Journal information
Proceedings of the National Academy of Sciences of the United States of America
National Academy of Sciences
National Academy of Sciences
0027-8424
Proceedings of the National Academy of Sciences of the United States of America/Journal Proceedings of the National Academy of Sciences of the United States of AmericaSCI
查看更多>>摘要：Bee venom can trigger harmful inflammatory reactions, and approximately 3% of the pop- j ulation in the United States J alone is known to be allergic to bee stings, which kill nearly 100 people every year through anaphylactic shock. Noah Palm and Ruslan Medzhitov (pp. 1809-1814) explored the mechanisms through which the venom of the European honey bee triggers inflammation, often marked by pain, redness, heat, and swelling around the site of the sting.
查看更多>>摘要：A growing body of evidence suggests that physical inactivity and obesity during childhood may compromise cognitive function and academic achievement. Marko Kanto-maa et al. (pp. 1917-1922) investigated whether childhood motor function underlies the effects of obesity and physical inactivity on academic achievement. The authors analyzed data from 8,061 boys and girls in the Northern Finland Birth Cohort 1986, and assessed each child's motor skills and academic performance at the age of 8 years via parental questionnaires and teacher ratings.
查看更多>>摘要：Assessments of the ecological implications of oil sands development in Alberta, Canada, have been hampered by a poor understanding of the background levels of toxic pollutants such as polycyclic aromatic hydrocarbons (PAHs), associated with bitumen mining. To address this knowledge gap, Joshua Kurek et al. (pp. 1761-1766) analyzed sediment cores from five lakes within a 35-km radius of major oil sands operations in Alberta, and one lake located approximately 90 km away from the development area.
查看更多>>摘要：Infiltrative brain tumors often seamlessly invade healthy brain tissue, posing a challenge for neurosur-geons trying to determine the tumors' boundaries. Livia Eberlin et al. (pp. 1611-1616) developed a mass spec-trometry-based strategy to rapidly characterize brain tumors based on their lipid profiles. The authors first acquired lipid profiles from 21 glioma and 11 meningioma samples using a technique called desorption electro-spray ionization mass spectrometry (DESI-MS), and used the mass spectra to develop a classification system to distinguish between these two primary types of brain tumors.
查看更多>>摘要：When a cell divides, a series of tightly regulated events are sequentially passed through to end up with two healthy daughter cells. A dysregulation of these steps such as an escape from cell cycle control checkpoints may lead to tumor formation. In recent years, it became increasingly clear that our 24-h internal clock also contributes to proper timing of cell cycle progression and likely acts as a tumor suppressor (1). Although epide-miological studies argue that chronic living against one's circadian clock increases the risk for cancer (2) and other diseases, the molecular mechanisms for circadian timing of the cell cycle are little understood.
查看更多>>摘要：As the world's largest reservoir of exchangeable carbon on millennial timescales, the oceans play a dominant role in global change. Indeed, the oceans currently act as a major sink for anthropogenic carbon (1), partially moderating increases in atmospheric CO_2 at the expense of a more acidic ocean. One of the great challenges for the next century is understanding how this shift in seawater chemistry will affect marine systems. Serving as a vivid microcosm for the ocean as whole, coral reefs display the beauty, diversity, and complexity of the ocean, while also exhibiting the ocean's sensitivity to environmental perturbations.
查看更多>>摘要：The extraction and processing of Canada's massive oil sands in the Athabasca region of northern Alberta have been marked by an ongoing controversy about the nature and extent of associated environmental impacts. Impacts include habitat destruction and fragmentation by surface mining and tailings disposal, depletion of water resources, greenhouse gas and chemical emissions, and the impacts of emissions on environmental and human health. The debate has been characterized by accusation, denial, emotion, and few reliable or appropriate data to clarify the issues. Thankfully, a pa-leolimnology study in PNAS by Kurek et al. (1) provides some badly needed perspective. They report the distribution of poly-nuclear aromatic hydrocarbons (PAHs) in sediment cores of lakes proximate to oil sands industries and as far as 90 km away.
查看更多>>摘要：Since the discovery in 2005 of the essential role of the liver-specific microRNA, miR-122, in HCV replication (1), the mechanism by which it stimulates this process has proved elusive. In PNAS, Li et al. demonstrate that miR-122 acts to shield the HCV genome against degradation by the cytosolic RNA exo-nuclease, Xrnl (2). Although this may be one way in which this microRNA promotes HCV replication, the authors also show that loss of Xrnl is not enough to promote miR-122 independent HCV replication, indicating that miR-122 exerts yet another function in the HCV lifecycle.
查看更多>>摘要：Early signaling events leading to protection in the heart under cardiac injury are poorly understood. We identified one such protein, A kinase interacting protein (AKIP1), as a modulator that responds to oxidative stress; up-reg-ulation of AKIP1 showed protection to ischemic injury through enhanced mitochondrial integrity. We show (pp. E387-E396) AKIP1 functions as a molecular scaffold via interaction with mitochondrial apoptosis inducing factor and increases protein kinase A activity. These mitochondrial signaling complexes assembled by AKIP1 alter the physiological response of the heart under ischemic stress. Understanding molecular activity and regulation of AKIP1 could lead to novel therapeutic approaches to limit myocardial injury.
Bruce RodenbornChih-Hung ChenHarry L. SwinneyBin Liu...
1574-1574页
查看更多>>摘要：The motion of bacteria and nanobots propelled by rotating helical flagella is often interpreted using resistive force theory (1, 2), which approximates the total force on a flagellum by summing the forces from each small segment, ignoring long-range fluid interactions. We test this theory in laboratory measurements on rotating helices and compare the measurements to predictions of resistive force theory and also to slender body and Stokeslet theories, which include long-range fluid interactions. The predictions from our numerical simulations of slender body and Stokeslet theories are found to agree well with our laboratory measurements, but the results of these simulations and experiments differ greatly from the predictions of resistive force theory.
NETL
NSTL
Natl Acad Sciences