What is Malaria?

Malaria is an infectious disease characterized by fever, chills, nauseau, and general discomfort. It is caused by a single-celled parasite known as Plasmodium that infects and destroys red blood cells. Malaria is transmitted or passed by a mosquito that bites an infected individual, carrying the parasite to another person. More than 24 million people are infected with Plasmodium each year and 3 million people, mostly children, die from the disease.

Malaria has been around since the times of Ancient Egyptians. It used to be very widespread, effecting all of Africa, Asia, South America, southern Europe, and even North America. Cases as far north as Philadelphia used to be common occurrences. Today, the areas affected by malaria are somewhat smaller, mainly due to changes in the water systems in the early 1990s. Sub-Suharan Africa, Central America, and Southeast Asia are still hard hit areas.

There are three main ways to combat malaria. The first is to get rid of the mosquito population that transmits the parasite. This can be done by removing free-standing water that has accumulated in jars, tires, and other containers. Sewers can also be built to drain areas that have a lot of free-standing water. Spraying houses with insecticides, which are chemicals that kill insects without harming the environment or humans, can also terminate mosquitoes. A common spray that was widely used was DDT, although its use has recently been banned. The second way to combat malaria is to reduce the amount of exposure that humans have to mosquitoes. This includes wearing long sleeved shirts and pants when outside, sleeping under bed netting, using insect repellent, and staying indoors at dawn and dusk--the two times of the day when mosquitoes are the most active. Finally, if someone comes down with malaria there is a wide range of drugs that can be used to treat that individual. The most commonly used drug is chloroquine.

Unfortunately, many people who are administered chloroquine do not finish their recommended treatment. This, coupled with dramatic, but insufficient, worldwide efforts in the 1950s to spray areas with constant or endemic malaria, have resulted in the emergence of drug-resistant parasites and pesticide-resistant mosquitoes. This emergence has serious consequences for world health. Areas that are now malaria-free may experience a reoccurence of the disease. Luckily, researchers around the globe are focusing on finding new treatments for eradicating malaria.

What is Arteriosclerosis?

Arteriosclerosis is such a big word, but if we break down the word, maybe we can understand what it means. Arterio is what doctors call anything that deals with arteries, or the blood vessels that carry blood away from the heart; doctors use the word sclerosis when talking about something hardening. So when a doctor says the word arteriosclerosis, they mean hardening of the arteries. An artery affected with arteriosclerosis has fatty streaks, which are white or yellow lines down the middle of the artery. By age 25 most Americans have a fatty streak present in one or more of their major arteries. Fatty streaks are typically larger and more numerous in individuals with high cholesterol diets. Anything high in animal fat is considered to be high in cholesterol.

Cholesterol needs to be carried in the blood so that cells throughout the body can get the cholesterol for their membranes and steroid production (a cell's surface is called a membrane.). Cholesterol mixes with blood like oil mixes with water. In order for it to be carried in blood, it must be carried by a lipoprotein, which is a combination of a lipid (like fat) and a protein. The lipoprotein can carry cholesterol because one side of the molecule likes blood and the other likes cholesterol so a bunch of these lipoproteins surround the cholesterol while it is carried in the blood. The process of getting the cholesterol-carrying lipoprotein to the cells goes wrong with arteriosclerosis.

To understand how arteriosclerosis affects an artery we must first look at what makes up an artery. Going from where the blood is in the artery and moving out, arteries are composed of special skin cells, muscle cells, and connective tissue with skin cells. The skin cells in your arteries are not the same as the skin cells on your arm, but they do protect and form a barrier just like the skin on your arm. The skin cells inside your blood vessels, scientifically known as endothelial cells, serve as a sort of filter between the blood and the cells. Part of the way they filter the blood is by taking in only specific components of the blood.

One of these components is the cholesterol-carrying lipoprotein called low-density lipoprotein, or LDL for short. The endothelial cell pushes the cholesterol out of the other side of the cell, away from the blood side. Cholesterol then gets 'stuck' in between the skin and muscle layer. Neighboring cells and other cholesterol-carrying LDL molecules join the stuck cholesterol and the fatty streak grows. In addition to other cells and cholesterol-carrying LDL molecules, calcium can deposit in the fatty streaks. The presence of calcium causes the arteries to become hard and rigid. Typically our arteries are elastic and can stretch to help keep our blood pressure constant. When arteries become hard and cannot stretch, our blood pressure can increase. This is one of the reasons why doctors, nurses, and physician assistants keep track of our blood pressure so they can tell when it has gone up.

As the fatty streak grows and the artery becomes more and more rigid, the opening for the blood to move through become smaller and smaller. Sometimes total blockage can occur arteries. The fatty streaks can also burst when they become large and broken off parts can block small arteries. When arteries are blocked, a stroke or heart attack can occur. This is why arteriosclerosis is a major health concern in America. The arteries most prone to fatty streaks are the ones that supply blood to the heart (coronary arteries) and to the head.

For more information on arteriosclerosis, visit the Vascular Disease Foundation's website at http://www.vdf.org.

What Is The Leonid Meteor Shower?

The week before Thanksgiving, many people enjoyed the Leonid meteor shower, which was one of the heavier showers in recent times. Even more amazing is the journey each meteor takes from its formation to its fiery end.

Meteors are typically small dust particles that originally were part of objects called comets. Comets are icy remnants of when our solar system was forming, large hunks of ice, rock, and dust. Comets occasionally will enter the inner part of the solar system and the heat of the Sun will start to evaporate the ices. The dust contained in the ice that evaporates will be ejected. This dust is called a meteoroid and will range in size from a few microns to several millimeters or larger. Some of the dust will collide with the Earth, typically at speeds on the order of 10 km/s (roughly 22,000 mph) and at a height of roughly 100 km or 62 miles. Larger particles (about a millimeter) will vaporize from the collision and create light, the familiar "shooting star" that people see. This is a meteor. If a particle survives its fiery entry into the Earth's atmosphere and lands, it is then called a meteorite.

What is special about the Leonids (and the Perseids in the summer) is that these are periodic showers that correspond to specific comets. The orbit of the Earth intersects the orbit of two comets, named Comet Swift-Tuttle and Comet Temple-Tuttle. Temple-Tuttle is responsible for the Leonids. The peak of the Leonids always occurs a few years after the comet passes by Earth on its journey around the sun, which is approximately every 33 years. After the peak, the Leonids aren't so spectacular. The reason for this is a large cloud of dust from Tempel-Tuttle follows a little bit behind the comet. When the Earth plows into this dust cloud, a meteor shower is born. The Leonids get their name because the meteors seem to radiate away from the constellation Leo. The Perseids seem to stream away from the constellation Perseus.

Meteors are very fun to go out and watch, but you need to find a dark place, dress warmly (even in summer), find a comfortable place and look up! Meteors can happen all over the sky so the best thing to do is lay back and try and look at as big a chunk of sky as possible. Then you relax and take in the beautiful sight of a teeny piece of dust that has spent billions of years locked up in ice, been thrown into space, and vaporized just for your enjoyment.

What is Cloning?

The word "cloning" generally conjures up images of armies of identical people, grown in huge test tubes, marching onward to some evil purpose. In reality, however, cloning is not nearly so sinister. Cloning simply refers to making identical copies of something from one unit. Usually when scientists talk about cloning, they refer to DNA, bacteria, or cells. Cloning bacteria is simple. It is done by separating bacteria out so that only one bacterium is present. This bacterium will divide and form a colony of millions, all of which are identical to the first one. Since they are identical, they are clones. DNA is cloned a little bit differently. Cloning DNA means making an exact copy of some part of the DNA that is of interest. This could be a gene, for example. That copy is then amplified into many copies. Since each one is identical, they are called cDNA, short for cloned DNA.

It is also possible to clone organisms bigger than bacteria. Plants are sometimes easy to clone. Certain types of plant cells, if treated properly, will grow into entire new plants, identical to the original plant on a genetic level. Animals are harder to clone, but it is very possible to clone them. Animals can be naturally cloned in the case of twins. With identical twins, the fertilized egg separates and grows to make two embryos instead of just one. This makes them clones, since they are genetically identical. Scientists have been able to duplicate this process in animals for a long time. A more important method of cloning is called somatic cell cloning. In this method, DNA from an adult animal is used to make a new organism. Basically an identical twin is created from an adult. This is much more difficult to do, because as animals grow and develop different organs and tissues, the DNA in those tissues is modified. Some DNA is locked up, unable to be used in different parts of the body. In order to make a complete cloned animal, however, all of the DNA must be accessible. Scientists conquered this challenge, and the first somatically cloned sheep was made in Scotland in the year 1997. Her name is Dolly.

Dolly was made by taking the DNA from her mother and putting it into a sheep egg cell that had had the DNA removed. This cell was then implanted in a normal sheep uterus and grew just like a normal embryo. Therefore, even though Dolly is a clone of her mother, she is several years younger. This is important to understand. Clones are not grown in tanks by scientists in labs. They do not emerge fully grown. There has been much discussion about human cloning recently. Because it is possible to clone sheep and other mammals, it should be possible to clone a human being. However, there are very serious ethical considerations to consider. It may be possible to clone yourself, and therefore have a supply of perfectly matched organs for transplantation. However, it is probably not ethical to create people just to harvest their organs. It may also be possible for such things to happen as a woman to give birth to her twin sister. Because of these unresolved issues and dangers, it is currently not legal for anyone in the United States to clone a human being using government money.

What Makes Stainless Steel Stainless?

The surface of most steel dulls and rusts when it is exposed to air and moisture. This chemical reaction with the environment (called corrosion) returns the metal to its mineral state; the steel is transforming back into iron ore. This process is prevented in stainless steels, which retain their metallic luster or shininess. By definition, stainless steels contain at least 10.5% chromium and often contain other elements like molybdenum and nickel. In stainless steels the chromium atoms at the surface react with air and moisture to form a tough, thin layer of protection. Just as a raincoat keeps you from getting wet in a rainstorm, the protective layer insulates the steel from the environment. This layer prevents the chemical reaction that produces rust.

Stainless steel is not a single material, but rather a broad category made up of dozens of different steels. Each stainless steel is unique, varying by the structure of the metal and the amount of alloying elements added to it, but they all increase resistance to rusting and other forms of corrosion. Some stainless steels are very hard and strong, but provide less protection from corrosion. Others are really good protectors, but are softer and weaker materials. A few stainless steels are both strong and very resistant to corrosion, however these are so expensive and are used only when it is absolutely necessary.

Little Lion Experiment:

Here is a simple experiment you can try in your own kitchen (with a parent's supervision). Many kitchens have a stainless steel sink and almost all have stainless steel cutting knives. However these two stainless steels are very different. To illustrate this you can test the stainless steels with a magnet; a refrigerator magnet will do nicely. Try sticking the magnet to the side of knife and to the side of the sink. What happens?

The magnet sticks to knife, but it won't stick to sink. This is because they are made from two very different types of stainless steel. A materials engineer selects the stainless steel with the best combination of strength, protection and affordability for each application. The knife must be hard to stay sharp and still not rust; it is made of ferritic stainless steel. The sink must have good protection because it often gets wet and it must be soft for shaping; it is made of austenitic stainless steel. The magnet is a simple way to tell these two types apart.

What is the Aurora?

Just in the last week or so, people have been talking about the aurora, because it was visible in our night skies not too long ago. If we're lucky, we will see it again. But what is it? The aurora borealis is a beautiful display of lights that can be seen over the northern pole of the Earth. It will appear in the northern part of the sky and have a ribbon-like shape that changes and shimmers in time. It will have hues that range from very pale white to green to blue and sometimes purple. Usually it is most visible in more northern latitudes, such as Canada and Alaska, although if it is bright enough and large enough it can be visible as far south as Florida.

There is a similar phenomenon called the aurora australis in the southern hemisphere that behaves the same way. And this gives us the first clues as to where this beautiful display of lights comes from. The north and south poles of the Earth correspond roughly to the poles of the earth's magnetic field. And just as iron filings are attracted to the north and south poles of a bar magnet, the Earth attracts charged particles such as protons to its poles. These particles originate from the sun, which gives off a slow stream of these particles in what is called the solar wind.

If these charged particles strike the atmosphere, they will inevitably crash into an air molecule or atom and often the collision will eject an electron. Since air molecules and atoms like to keep their electrons they will eventually snag a new electron. That process releases light and voila you have an aurora. Because the aurora depends on the solar wind, as the solar wind changes so does the aurora. If there are lots of particles streaming from the sun, then there will be a bright aurora. This year we are lucky, the sun is very active and so will often eject lots of material into space which causes very strong and beautiful auroras.

The last time I saw the aurora was here in State College while watching for meteors. A few days before, the sun had a huge flare which released a very strong solar wind, creating a beautiful addition to the already fun hunt for meteors! If you want to try to see the aurora, the best place to be is somewhere dark and relatively flat so that you can have a good view of the horizon. You need to look towards the North.

The best way to do that is to find the Big Dipper, which looks like a huge ice cream scooper. The two stars at the edge of the scooper form a line that will point you towards the pole star or Polaris, which is due north. You also need to go out on a night when they predict that the aurora will be strong, since we don't often have a good chance of seeing it. Websites like space.com, spaceweather.com and skyandtelescope.com will have stories with links to forecasting sites and email alerts so you can try and find the likely days of next big storm.

What is Thermodynamics?

The history of thermodynamics dates back to the nineteenth century. The field was developed to describe the operation of the steam engine, hence the title thermo (heat) - dynamics (power). In present day, the study of thermodynamics includes so much more than just the study of steam power. It is used to understand all sorts of thing including reactions in the cells in your body and mixtures of different liquids and gases.

Thermodynamics is based on three main laws. Like many scientific laws, these laws cannot be proven through math, but have not been proven wrong in nature. These laws are the same laws that scientists and engineers discovered when they were looking at steam and steam engines. They learned that the laws that steam obey in the engine works for all sorts of systems and chemicals.

The first law of thermodynamics states that the amount of energy in the universe does not change. When energy disappears in one form, it appears as another at that same moment. To understand this better we will look at the two main types of energy, kinetic and potential. Kinetic is the energy of motion and potential is stored energy. A car at the top of a big hill is full of potential energy, because of the difference in height at the top and bottom of the hill. As the car goes down the hill, potential energy is released in the form of kinetic energy. Potential energy can also be stored in chemical bonds. Bonds are what keep molecules together, like hydrogen and oxygen in water. When a molecule is made from atoms, energy is used to create the bonds. A good example of chemical bonds releasing energy is a campfire. The chemical bonds in the wood break producing heat and light. Sometimes a campfire crackles; this is another way energy is expressed, sound. Energy can be released from bonds as heat, light and sound.

The second law of thermodynamics says that the amount of energy a system puts out can not be greater than the amount of energy put into the system, or simply, you can not get something for free. This rule also tells us that nothing is perfect. We can look at a car engine as an example. All of the energy stored in the chemical bonds of the gas is not converted completely to energy to drive your car. The law tells us that the energy in a system cannot be made totally into work, that no engine is perfect. This is why a perpetual motion machine cannot be made. A perpetual motion machine is an ideal, fantasy machine that the operator can start moving and run forever without adding any energy once it has started. Here is a web page that discusses the history of the perpetual motion machine: http://www.phact.org/e/dennis4.html.

The third law of thermodynamics states that all things will become less and less organized. Scientists and engineers have a term called entropy. Entropy helps relate how chaotic or disorganized a system is. At the coldest temperature, absolute zero (-270 degrees Celsius), the absolute value of entropy is zero. An example of why this law is thought to be true is the constant expansion of the universe. The entropy at the time I wrote this article is less then the entropy when you read this article!

The laws of thermodynamics are universal for everything and have yet to be proven wrong!