Wednesday May 4, 2011
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Cellular protein TIM-1 acts as a receptor for Ebola virus and Marburg virus. Microscope image shows TIM-1 expression (in green) on the surface of human airway cells.
Credit: University of Iowa |
Ebola is a deadly virus that damages and destroys blood vessel walls, leading to hemorrhagic fever. Researchers from the University of Iowa have identified a cellular protein, TIM-1, that acts as a receptor for the Ebola virus and a related virus known as the Marburg virus. Both viruses use TIM-1 as a receptor to infect cells. TIM-1 is expressed in epithelial cells which cover the outer skin layer and line organs and cavities of the body.
The researchers also found that the antibody ARD5 is effective at preventing Ebola and Marburg from infecting cells that express TIM-1. While Ebola and Marburg can infect other cells that do not express TIM-1, the researchers believe that cells that express TIM-1 maybe conduits that give these viruses access to other cells of the body. TIM-1 is expressed in cells that line the mucous membrane surfaces in the airways and eyes, as well as in several other body tissues. It is believed that Ebola is transmitted via inhalation or by contact with the eyes.
Learn more about this study, see:
Saturday April 30, 2011
A node is a specialized type of tissue that behaves as both muscle and nervous tissue. When nodal tissue contracts (like muscle tissue) it generates nerve impulses (like nervous tissue) that travel throughout the heart wall. The heart has two nodes that are instrumental in cardiac conduction, which is the electrical system that powers the cardiac cycle. These two heart nodes are the sinoatrial (SA) node and the atrioventricular (AV) node.
The sinoatrial node, also referred to as the pacemaker of the heart, coordinates heart contractions. It generates nerve impulses that travel throughout the heart wall causing both atria to contract. The atrioventricular node lies on the right side of the partition that divides the atria, near the bottom of the right atrium. When the impulses generated by the SA node reach the AV node, they are delayed for about a tenth of a second. This delay allows the atria to contract, thereby emptying blood into the ventricles.
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Thursday April 28, 2011
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This plant-eating dinosaur, Protoceratops andrewsi, was active day and night.
Credit: Lars Schmitz, UC Davis |
By examining the eyes of fossil animals, researchers have determined that some dinosaurs hunted at night while others foraged both day and night. Unlike mammals and crocodiles, dinosaurs have a bony structure called a scleral ring in their eye. This ring is also found in lizards and birds. By measuring the size and dimensions of the eyes and scleral rings in both living animals and fossilized dinosaurs, the researchers were able to determine whether certain dinosaurs were nocturnal, active during the day, or active both day and night.
In the study, it was discovered that animals with small openings in the middle of the scleral ring were active during the day. Those with large openings were active at night while those with intermediate openings were active both day and night. The ring measurements of dinosaur fossils suggested that large herbivores were active both day and night while smaller carnivorous predators, such as velociraptors, hunted at night. Flying dinosaurs such as pterosaurs hunted mostly in the day, while some flying animals hunted at night.
Learn more about this study, see:
Wednesday April 27, 2011
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| Credit: National Institutes of Health |
Broca's area is one of the main areas of the cerebral cortex responsible for producing language. This region of the brain was named for French neurosurgeon Paul Broca who discovered the function of Broca's area while examining the brains of patients with language difficulties. Broca was the first to indicate that a language center of the brain is located in the lower portion of the left frontal lobe. He discovered that this area controls motor functions involved with speech production.
Persons with damage to Broca's area of the brain can understand language but cannot properly form words or produce speech. If asked a question, they may respond with a sequence of words or sounds that do not make sense. Broca's area is connected to another brain region known as Wernicke's area. Wernicke's area is associated with processing and understanding language. Unlike those with damage to Broca's area, persons with damage to Wernicke's area do not comprehend written or spoken language.
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