October 31, 2009

Halloween Special: An Analysis of Blood Spatter from a Chainsaw

weed chainsaw massacre (courtesy of flickr user 19melissa68)

weed chainsaw massacre (courtesy of flickr user 19melissa68)

Here’s a shocker: Horror films like Texas Chainsaw Massacre don’t get the chainsaw spatter right, according to the Journal of Forensic Sciences.

The reason for the study is sad—a woman was reported missing in 2005, and the police found evidence that she had been killed and dismembered in her basement (a few dabs of fresh paint on the walls, small pieces of bone, a receipt for an electric chainsaw). The investigators, possibly having watched a few too many horror films, didn’t think that there was enough blood and tissue spatter in the small room if a human body had been dismembered there by someone wielding a small chainsaw. And there was the question of whether or not the chainsaw itself was powerful enough to accomplish the job without getting stuck in flesh and bone.

A University of South Dakota pathologist got involved. He obtained the same kind of chainsaw indicated in the receipt and a 200-pound female pig, deceased, and created a room the approximate size of the basement using white sheets. He let the pig rest for two days to simulate the time between when the woman had been reported missing and when the chainsaw was purchased. And then he started hacking away.

The chainsaw was certainly powerful enough to cut through the tissue and bone. And the pathologist discovered that if the blade was held parallel to the floor there was very little spatter, similar to what was found at the crime scene. (Vertical positioning of the blade or use of a freshly killed pig increased the amount of spatter on the sheets.) The researcher concluded:

These experiments have shown that a human body may be easily dismembered with a chainsaw, even a smaller electric-powered model….Despite popular beliefs fueled by crime scene shows on television and recent Chainsaw Massacre movies, postmortem dismemberment does not necessarily produce a large amount of blood spatter at a dismemberment scene….With a horizontally oriented chainsaw, therefore, the majority of the tissue and blood will be found on the ground beneath the saw. If the chainsaw discharge chute, however, is not directed towards the ground, then a large volume of blood and tissue, and subsequent spatter, could be expected some distance from the saw.

Something to consider when writing or filming your next scary movie.



Posted By: Sarah Zielinski — Science 101, The Human Body | Link | Comments (0)




October 30, 2009

Picture of the Week–The Kappa Crucis Cluster, a.k.a. the “Jewel Box”

jewel-box-stars

The Abbé Nicolas-Louis de Lacaille was the first to find this cluster of stars, in 1751 while on an astronomical expedition to the Cape of Good Hope (South Africa). The Kappa Crucis Cluster (NGC 4755), which resides near the Southern Cross, received the nickname the “Jewel Box” during the next century, when astronomer John Herschel viewed it through his telescope and saw the stars were different colors—pale blue and orange. He wrote: “The stars which compose it, seen in a telescope of diameter large enough to enable the colours to be distinguished, have the effect of a casket of variously coloured precious stones.”

We now know that the cluster is about 6,400 light-years away from Earth and around 16 million years old. The stars in the Jewel Box all formed from the same cloud of dust and gas, are about the same age and have similar chemical compositions. The image above was taken recently with MPG/ESO 2.2-meter telescope at the La Silla Observatory in Chile. Scientists use clusters like this one to study the evolution of stars. (Image credit: ESO. Click here to find additional images of the cluster, including one from the Hubble Space Telescope.)

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Posted By: Sarah Zielinski — Picture of the Week, The Universe | Link | Comments (2)




October 29, 2009

Vaccine Week: Swine Flu Edition

H1N1 (swine) flu is in the news again (courtesy of flickr user Dr Craig)

H1N1 (swine) flu is in the news again (courtesy of flickr user Dr Craig)

Around the country, people are lining up to be vaccinated against the H1N1 flu virus. Surprising Science has spent the last three days discussing the history and science of vaccines (see A Brief History and How Vaccines Work, Success Stories, and A History of Vaccine Backlash). Today we answer some of the more common questions about the swine flu vaccine.

Who should get the H1N1 flu vaccine?

There is currently not enough vaccine for everyone who wants it. Vaccines take time to produce and this one has been rolling off the line for just a few weeks. As of Tuesday there were about 22.4 million doses available around the United States. The goal is to have 250 million doses by the end of flu season next spring. The Centers for Disease Control and Prevention have recommended that certain groups get vaccinated first:
•    pregnant women
•    people who live with or care for children under six months of age
•    young people age six months to 24 years
•    people 25 to 64 who are at higher risk for flu complications due to a health condition or compromised immune system
•    health care and emergency medical service personnel

Why are these groups first?

Pregnant women and young people seem to be especially vulnerable to the H1N1 virus. Babies under six months of age cannot be vaccinated, so it is important to limit their exposure to the virus by vaccinating people who care for them. People with certain health conditions or who have a compromised immune system have a higher risk of having serious flu complications if they get the flu. And medical personnel are the people most likely to come in contact with the virus.

What if I’m not in one of these groups?

Wait your turn. There will be enough vaccine eventually. And if you get the H1N1 flu, it won’t be fun but also probably won’t do you long-term harm. In the meantime, the CDC recommends taking everyday preventative actions like hand washing and avoiding contact with sick people. (And if you get sick, please stay home.)

Is the vaccine safe?

The H1N1 vaccine is made the same way as the seasonal flu vaccine. The manufacturers just tweaked the recipe with the new virus. The Food and Drug Administration approved the vaccine in September. People with allergies to chicken eggs, however, should not be vaccinated as eggs are used to make the vaccine.

I got a seasonal flu vaccine last month. Why won’t that work against H1N1?

For the same reason that your flu vaccine from last year doesn’t protect you from this year’s seasonal flu: There are many different types of flu virus, and they mutate over time. When you are exposed to one type, your body’s immune system learns to protect you from that type only. The others are too different to register with your immune system as the same virus.

I’ve heard that in other countries the vaccine contains squalene. What is it and why is it in their vaccine and not ours? And what about thimerosal?

Squalene is a type of naturally-occurring oil found in plants and animals (including humans). Squalene is a component of some adjuvants of vaccines. Adjuvants help a vaccine’s effectiveness by boosting the immune response. Some countries have added the squalene-containing adjuvant to their vaccine mix for H1N1 because it causes a lower dose of vaccine to be effective; that is, it will allow people to get more doses out of the same batch of vaccine. The World Health Organization has found no evidence of any adverse events in vaccines containing the squalene adjuvant.

The United States government chose not to use any adjuvants in the H1N1 mix in this country. However, some formulations of the vaccine do contain thimerosal, a mercury-based preservative that has been used in vaccines for decades. Getting mercury injected into your body may sound a little scary. But concerns about safety of thimerosal are unfounded. Some parents worry that thimerosal may cause autism in young children, but there is no evidence of this. Several studies in recent years have examined the possibility, but no association has ever been found.

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Posted By: Sarah Zielinski — In the News, Science 101, The Human Body | Link | Comments (2)




October 28, 2009

Vaccine Week: A History of Vaccine Backlash

In light of President Obama’s declaration that the outbreak of the H1N1 virus is a national emergency, Surprising Science is setting this week aside to discuss the history and science of vaccines and their importance in battling diseases, including swine flu. See Monday’s post for part 1, A Brief History and How Vaccines Work, and yesterday for part 2, Success Stories.

It’s kind of startling that the idea of vaccines ever caught on. There is an amazing amount of trust needed: A person—often a complete stranger—is injecting you with a foreign substance. You have to trust that the substance is really what you’ve been told it is, that it has been sufficiently tested and is safe, and that it will work as advertised and not hurt you.

An 1802 illustration depicts Edward Jenner vaccinating a young woman. Several former patients demonstrate the effects of the vaccine—miniature cows erupt from their bodies. (Courtesy of the National Library of Medicine)

An 1802 illustration depicts Edward Jenner vaccinating a young woman. Several former patients demonstrate the effects of the vaccine—miniature cows erupt from their bodies. (Courtesy of the National Library of Medicine)

Despite this, most people trust the doctors, science and government and do get vaccinated. A small percentage, however, choose not to be vaccinated (or not to have their children vaccinated). And it’s been this way almost since Edward Jenner first began vaccinating people against smallpox (see the illustration).

Decades after Jenner’s discovery, the British government got involved in vaccination by passing a law in 1840 that provided free smallpox vaccinations to the poor. But later efforts didn’t go over so well. A 1853 law required all infants be vaccinated in the first three months of life and threatened parents who did not vaccinate their children with a fine or imprisonment. Riots soon broke out in several towns. In London, an Anti-Vaccination League was founded. In 1867, after the law was extended to children up to age 14, the Anti-Compulsory Vaccination League was founded. Opposition now focused on the law’s threat to personal liberty. (“As parliament, instead of guarding the liberty of the subject, has invaded this liberty by rendering good health a crime…parliament is deserving of public condemnation.”)

In the late 19th century, anti-vaccination movements spread across Europe and into the United States, where they succeeded in repealing compulsory vaccination laws in several western and Midwest states.

But despite the controversy, protests and pamphlets, the doctors, science and governments eradicated smallpox from the United States by 1950 and from the entire world by 1980.

Along the way, though, anti-vaccination sentiments have resulted in serious harm. For example, when the majority of the residents of Stockholm, Sweden refused vaccination for smallpox in the early 1870s, they were left vulnerable to the disease. The city experienced a major epidemic in 1874, after which vaccination was again popular.

Efforts to eradicate polio—a disease now confined to just a few countries—came off track in Nigeria due to a 2004 rumor that the vaccine “contained birth control drugs as part of a secret western plot to reduce population growth in the Muslim world.” Polio is on the rise again in Nigeria, and more than 100 children have been left paralyzed by the disease this year.

And in places like Europe, Australia and the United States, in communities where parents have stopped vaccinating their children for fear that common childhood immunization causes autism (a fear that is completely unfounded), diseases that had become rare—like measles and pertussis—are making a comeback, as Wired magazine notes in their November issue:

“I used to say that the tide would turn when children started to die. Well, children have started to die,” [pediatrician and vaccine researcher Paul] Offit says, frowning as he ticks off recent fatal cases of meningitis in unvaccinated children in Pennsylvania and Minnesota. “So now I’ve changed it to ‘when enough children start to die.’ Because obviously, we’re not there yet.”

The anti-vaccination movement ebbs and flows over time, with fear of disease fighting mistrust of doctors, science and government. Which will win? If history is any guide: neither. But doctors, science and government will all need to work together to find a way to protect public health. And then, perhaps, they will find more vaccine success stories along the way.

Tomorrow—Vaccine Week, Day 4: Swine Flu Edition



Posted By: Sarah Zielinski — History of Science, Must Reads, The Human Body | Link | Comments (2)




October 27, 2009

Vaccine Week: Success Stories

In light of President Obama’s declaration of “national emergency” imposed by the outbreak of the H1N1 virus, Surprising Science is setting this week aside to discuss the history and science of vaccines and their importance in battling viruses and diseases, including swine flu. See yesterday’s post for part 1, A Brief History and How Vaccines Work.

A sign warning of a smallpox hospital in Yorkshire, England, 1953 (WHO photo, courtesy of the National Library of Medicine)

A sign warning of a smallpox hospital during a 1953 outbreak of the disease in Yorkshire, England (WHO photo, courtesy of the National Library of Medicine)

Smallpox: Once one of the world’s most dreaded diseases, smallpox killed as many as 30 percent of people who became infected with it and left survivors deeply scarred; no effective treatment was ever found. English physician Edward Jenner in 1796 discovered how to use cowpox virus to vaccinate individuals against smallpox. Vaccination efforts grew over the next century. The last reported case in the United States occurred in 1949, and vaccination ended here in 1971. The last case of smallpox in the world occurred in Somalia in 1977, and the disease was declared to be eradicated in 1980.

Polio: The virus mainly attacks children under the age of three, and infection can result in severe paralysis and death. Vaccines developed in the 1950s and 1960s have eliminated the disease from much of the world. However, cases are still found in several countries, and immunization efforts continue in Africa and Asia.

Measles: Measles is a respiratory disease that is accompanied by a rash. In the United States and other countries where measles vaccination is common, incidence of the disease has become rare, which is good because it can lead to pneumonia, encephalitis or death. Worldwide, there are about 10 million cases of measles each year and 197,000 deaths. But if there were no vaccinations, the World Health Organization has estimated that 2.7 million people would die of the disease each year.

Hib meningitis: The bacterium Haemophilus influenzae type b causes meningitis and pneumonia. It used to be the leading cause of bacterial meningitis in children. However, since the development of vaccines for the disease in the 1990s, it has been nearly eliminated in industrialized nations. The story isn’t so positive in the developing world, though. There, Hib infects about three million individuals and kills about 386,000 each year, mostly children under the age of five.

Tetanus: “He stepped on a rusty nail and died” was once a common epitaph. Tetanus, also called lockjaw, isn’t actually caused by the rust; it’s caused by the spores of the bacterium Clostridium tetani. A person becomes infected when dirt enters a wound. Babies can also become infected at birth following a delivery under non-sterile conditions. Infection results in stiffness, muscle spasms and, about a fifth of the time, coma and death. With increased rates of vaccination, though, incidence of the disease is declining worldwide.

Diphtheria: This upper respiratory tract infection is caused by the Corynebacterium diphtheriae bacterium. It has a fatality rate of about 5 to 10 percent, though that rate climbs to 20 percent among the very young and the elderly. Vaccination has driven the incidence of the disease in the United States from hundreds of thousands of cases per year in the 1920s to just a handful of cases today.

Tomorrow—Vaccine Week, Day 3: A History of Vaccine Backlash



Posted By: Sarah Zielinski — History of Science, The Human Body | Link | Comments (2)




October 26, 2009

Vaccine Week: A Brief History and How Vaccines Work

La Vaccine, 1827 (courtesy of the National Library of Medicine)

La Vaccine, 1827 (courtesy of the National Library of Medicine)

In light of President Obama’s declaration of “national emergency” imposed by the outbreak of the H1N1 virus, Surprising Science is setting this week aside to discuss the history and science of vaccines and their importance in battling viruses and diseases, including swine flu.

More than two millennia ago in China or India, someone noticed that people who suffered and recovered from certain diseases never became reinfected. In a leap of logic, the person who noticed the connection tried to prevent the disease by inoculating themselves (or perhaps someone else) with a bit of infected matter.

That idea, now called vaccination, bumbled along through history until 1796. That’s when an English physician named Edward Jenner noticed that milkmaids rarely got smallpox, though they often had blisters from cowpox, which they caught from their cows. Jenner thought that the cowpox might prevent the women from getting smallpox. To test his idea, he took some material from the cowpox blister of a milkmaid and inoculated 8-year-old James Phipps. Six weeks later, Jenner injected young Phipps with fluid from a smallpox sore; Phipps didn’t contract smallpox.

Over the next decades, smallpox vaccination spread, and it was a common practice by the end of the 19th century. Around that time, two more vaccines were developed—by Louis Pasteur—against anthrax and rabies. The 20th century would see the development of vaccines for more than a dozen other diseases, including polio, measles and tetanus.

Long after Jenner’s first discovery, biologists would discover how vaccines work to prime our immune systems to fight off infections:

Though the original smallpox vaccine used a related virus, cowpox, most vaccines use a weakened or dead form of whatever disease they’re meant to prevent. Some of these vaccines will also include a substance called an adjuvant that boosts the effectiveness of the vaccine. (Scientists figured out the workings of alum, one type of adjuvant, last year.)

When the vaccine is injected, a person’s immune system recognizes it as a foreign substance. Immune cells called macrophages digest most of the foreign material, but they keep a portion to help the immune system remember it. These identifying molecules are called antigens, and macrophages present these antigens to white blood cells called lymphocytes (which come in two types: T cells and B cells) in the lymph nodes. A mild immune response occurs, and even after the vaccine material is destroyed, the immune system is primed for a future attack.

The next time that a microbe with those antigens enters the body, the lymphocytes are ready to quickly recognize the microbe as foreign. When that happens, B cells make antibodies that attack the invading microbe and mark it for destruction by macrophages. If the microbe does enter cells, T cells attack those infected cells and destroy them before the disease can multiply and spread. The microbe is defeated before it can get a foothold in the body, before the person gets sick.

Tomorrow–Vaccine Week, Day 2: Success Stories



Posted By: Sarah Zielinski — Science 101, The Human Body | Link | Comments (4)




October 23, 2009

Picture of the Week–Open-pit Copper Mine

ASTER image of Morenci open-pit copper mine in southeast Arizona (credit: NASA)

ASTER image of Morenci open-pit copper mine in southeast Arizona (credit: NASA)

Splatter of colors
Seen high up from outer space
Pretty like a rainbow
Natalie, age 8, Illinois

Mining doesn’t generally result in a prettier landscape, but it seems when you view the landscape through NASA’s ASTER instrument on the satellite Terra, beauty easily emerges. The image above is the Morenci open-pit copper mine in southeast Arizona. The mine is the largest producer of copper in North America. (The author of the poem is a Girl Scout; NASA partnered with some scouts last year and challenged them to write poems based on the agency’s images.) NASA highlights this and other images from its vast library in the NASA Images blog, which was begun earlier this year.

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Posted By: Sarah Zielinski — Earth, Picture of the Week | Link | Comments (1)




October 22, 2009

Thursday News Roundup — Black Holes, Traveling to Titan, and More Spiders

  • According to New Scientist, physicists Tie Jun Cui and Qiang Cheng of the Southeast University in China have succeeded in creating the first black hole, built to absorb and trap solar energy. Based on a theory from Professors Evgenii Narimanov and Alexander Kildishev of Purdue University, the Chinese scientists used strips of “meta-materials” (previously used to create Potter-esque “invisibility cloaks”) to recreate the structure of a black hole. “When the incident electromagnetic wave hits the device, the wave will be trapped and guided in the shell region towards the core of the black hole, and will then be absorbed by the core,” says Cui. “The wave will not come out from the black hole.” According to Narimanov, should the creation work, it would allow for the collection of solar energy in areas with little exposure to light.
  • Ever wonder what it’s like inside a black hole? Scientists at UC-Boulder created this animation to theorize what the experience would look like:
  • In air and space news, one lucky robot is predicted to sail on Titan, one of Saturn’s moons. The idea to cruise in space was inspired by the discovery that Titan resembles Earth in many habits, particularly weather-wise. Titan experiences rain, wind, and has many lakes, however, liquid methane and ethane take the place of water. Ellen Stofan, a geologist with Proxemy Research in Maryland, explains that the lake-lander will fulfill one of the three-probe plan to explore this interesting moon. A “balloon-mounted vehicle and an orbiter” will complete the mission, enabling NASA to fully view and discover every region of Titan.
  • From the BBC comes news of a “veggie spider” or Bagheera kiplingi, the only arachnid to feast only on plants. Avoiding ants and waiting patiently to snag a piece of its’ favored acacia plants – known as Beltian bodies, the spider really has to work for its’ vegetarian meals. Found in Central American and Mexico, this spider is perhaps the only one not feared by the people.
  • Due to excessive animal poaching (104 per day!), African elephants will be extinct in little over 15 years, according to the International Fund for Animal Welfare. Despite the international ban on ivory sales, the illicit trade continues.

— Compiled by Audrey Reinhardt



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