ANN ARBOR, Mich. -- Dying in America is an expensive process, with about one in four Medicare dollars going to care for people in their last year of life. But for African Americans and Hispanics, the cost of dying is far higher than it is for whites.

And despite years of searching for the reason, no one has quite figured out why.

A new study by a University of Michigan Medical School team tried to get to the bottom of this expensive mystery with the most detailed study to date. The team published their findings today in the Journal of the American Geriatrics Society.

An Umeå-based team in collaboration with US researchers reveals a new link between nicotine and inflammation. They report that nicotine strongly activates immune cells to release DNA fibres decorated with pro-inflammatory molecules, so called neutrophil extracellular traps (NETs). The continuous exposure to these NETs can harm the tissue and could explain the hazardous consequences of tobacco consumption for human health.

By analyzing medical records gathered over three decades on more than 11,000 Americans participating in a federally funded study, researchers at Johns Hopkins Medicine say they have more evidence that driving diastolic blood pressure too low is associated with damage to heart tissue.

The researchers caution that their findings cannot prove that very low diastolic blood pressure -- a measure of pressure in arteries between heartbeats when the heart is resting and also the "lower" number in a blood pressure reading -- directly causes heart damage, only that there appears to be a statistically significant increase in heart damage risk among those with the lowest levels of diastolic blood pressure.

Populations of New World screwworm flies - devastating parasitic livestock pests in Western Hemisphere tropical regions - could be greatly suppressed with the introduction of male flies that produce only males when they mate, according to new research from North Carolina State University, the USDA's Agricultural Research Service, the Panama-United States Commission for the Eradication and Prevention of Screwworm (COPEG) and the Smithsonian Tropical Research Institute.

Withholding tetracycline in the larval diet essentially means "It's a boy" when the genetically modified male flies successfully mate with females in the field, says Max Scott, an NC State entomologist who is the corresponding author of a paper describing the research.

When it comes to the billions of neurons in your brain, what you see at birth is what get -- except in the hippocampus. Buried deep underneath the folds of the cerebral cortex, neural stem cells in the hippocampus continue to generate new neurons, inciting a struggle between new and old as the new attempts to gain a foothold in memory-forming center of the brain.

In a study published online in Neuron, Harvard Stem Cell Institute (HSCI) researchers at Massachusetts General Hospital and the Broad Institute of Harvard and MIT in collaboration with an international team of scientists found they could bias the competition in favor of the newly generated neurons.

A new hypothesis aims to explain how the complex vertebrate body, with its skeleton, muscles, nervous and cardiovascular systems, arises from a single cell during development and how these systems evolved over time. They give it a proper name, embryo geometry, but scientists are going to hold off on calling it a theory until it shows some chance of validation. Until then, it is like String Theory, more philosophy than science.

The paper, along with illustrations - or "blueprints" - depicting how it applies to different vertebrate organ systems, is in Progress in Biophysics&Molecular Biology.