Cancer

Increased risk for oral cancer with exposure to high PM2.5

(HealthDay)—Taiwanese men exposed to high concentrations of fine particulate matter 2.5 (PM2.5) have an increased risk for oral cancer, according to a study recently published in the Journal of Investigative Medicine.

Neuroscience

How to 'jumpstart' rhythmic breathing at birth

The common expression, 'As easy as breathing,' is truly misleading. Breathing, as it is performed by higher vertebrates, is a complex biological function involving many types of neurons. It requires chemosensory neurons to ...

Health

A breath of fresh air for hospitals

Indoor air quality is important for everyone's health but perhaps no more so than in different kinds of medical centre. A team from India has investigated hospital waiting room air quality in terms of patient comfort with ...

Diseases, Conditions, Syndromes

Carbon dioxide reduces belly fat

The first randomized, controlled trial testing carbon dioxide gas injections (carboxytherapy) to reduce belly fat found the new technique eliminates fat around the stomach. However, the changes were modest and did not result ...

Diseases, Conditions, Syndromes

Putting lungs under less stress

The numbers are grim: Of the 200,000 Americans diagnosed with Acute Respiratory Distress Syndrome (ARDS) each year, 30 to 50 percent will die. But, clinical researchers at the University of Missouri School of Medicine's division ...

Genetics

Does your DNA really change in space?

Results from an important NASA experiment – in which astronaut Scott Kelly spent one year in space while his identical twin brother Mark stayed on Earth – have started to come in. Last week, a number of media outlets ...

Overweight & Obesity

When we lose weight, where does it go?

The world is obsessed with fad diets and weight loss, yet few of us know how a kilogram of fat actually vanishes off the scales.

Neuroscience

Star-like cells may help the brain tune breathing rhythms

Traditionally, scientists thought that star-shaped brain cells called astrocytes were steady, quiet supporters of their talkative, wire-like neighbors, called neurons. Now, an NIH study suggests that astrocytes may also have ...

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Carbon dioxide

Carbon dioxide (chemical formula: CO2) is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. It is a gas at standard temperature and pressure and exists in Earth's atmosphere in this state.

Carbon dioxide is used by plants during photosynthesis to make sugars, which may either be consumed in respiration or used as the raw material to produce other organic compounds needed for plant growth and development. It is produced during respiration by plants, and by all animals, fungi and microorganisms that depend either directly or indirectly on plants for food. It is thus a major component of the carbon cycle. Carbon dioxide is generated as a by-product of the combustion of fossil fuels or the burning of vegetable matter, among other chemical processes. Large amounts of carbon dioxide are emitted from volcanoes and other geothermal processes such as hot springs and geysers and by the dissolution of carbonates in crustal rocks.

As of March 2009[update], carbon dioxide in the Earth's atmosphere is at a concentration of 387 ppm by volume. Atmospheric concentrations of carbon dioxide fluctuate slightly with the change of the seasons, driven primarily by seasonal plant growth in the Northern Hemisphere. Concentrations of carbon dioxide fall during the northern spring and summer as plants consume the gas, and rise during the northern autumn and winter as plants go dormant, die and decay. Carbon dioxide is a greenhouse gas as it transmits visible light but absorbs strongly in the infrared and near-infrared.

Carbon dioxide has no liquid state at pressures below 5.1 atmospheres. At 1 atmosphere (near mean sea level pressure), the gas deposits directly to a solid at temperatures below −78 °C and the solid sublimes directly to a gas above −78 °C. In its solid state, carbon dioxide is commonly called dry ice.

CO2 is an acidic oxide: an aqueous solution turns litmus from blue to pink. It is the anhydride of carbonic acid, an acid which is unstable and is known to exist only in aqueous solution.

CO2 is toxic in higher concentrations: 1% (10,000 ppm) will make some people feel drowsy. Concentrations of 7% to 10% cause dizziness, headache, visual and hearing dysfunction, and unconsciousness within a few minutes to an hour.

This text uses material from Wikipedia, licensed under CC BY-SA