Author Archives: curiouscat

Finding Open Scientific Papers

Sandra Porter has posted a series of posts on finding scientific papers for free: A day in the life of an English physician – What’s the best way to find free scientific publications? – My new favorite method – one more experiment

via: Finding scientific papers for free

Extensively Drug-resistant Tuberculosis (XDR TB)

Superbug poses dire threat to Africa

The journey to Dr. Moll’s terrifying discovery began in early 2005, when he noticed something peculiar. The staff at his hospital had become accustomed to the marvellous “Lazarus effect” of anti-retroviral treatment for AIDS: seeing desperately sick people quickly start gaining weight and return home or go back to work. But now, in his ward, he had two men in their 30s on ARVs whose HIV infections were suppressed to undetectable levels. Yet their TB, which would normally have cleared up in a matter of weeks, kept getting worse.

He suspected multidrug-resistant TB, or MDR, believed at the time to be as bad as the disease could get. So he collected sputum from 45 patients and sent it off to a lab in Durban for cell culturing. (The only way to tell if a TB strain is drug-resistant is to grow cultures from a patient sample, zap it with the different drugs and see which, if any, fail to kill it.) The process takes six to eight weeks. “In that time, we more or less forgot about it,” Dr. Moll said. One of his two young men died.

But the phone call from the lab, when it eventually came, slammed the issue to the top of their agenda: Of the 45 samples, 10 were indeed drug-resistant. But they weren’t resistant to just one or two of the drugs used against TB. They were resistant to all six medications available for use in Tugela Ferry. In other words, there was nothing to cure that TB at all.

As we have discussed previously, antibiotic resistance is a huge problem today and especially looming in the future. Perhaps we will find new fantanstic cures but the failure to take sensible action puts us at great risk.

New Neurons in Old Brains

More research on feeding your newborn neurons, New Neurons in Old Brains Exhibit Babylike Plasticity:

Using a retrovirus that targets dividing, or reproducing, cells, the team tracked new neurons in the hippocampus (a midbrain structure involved with learning and memory) from their births to their deaths. The scientists could determine the behavior of cells by measuring their electrophysiological activity during different phases. “In young animals, cells are very active, very plastic, and they can change their properties readily,” he says. “This whole process [also] happens in the environment of adult circuitry.”

The team found that there is a two-week window, or critical period, about a month after these new cells hatch during which they act like the neurons of a newborn baby. The researchers cued the new cells with a pattern of electrical activation that mimics the sequence that takes place in the brain of a mouse as it learns about a special spot (such as a corner in its cage where it may receive food or a shock). During this time, the cell synapses (connections that allow neurons to communicate with each other) that are artificially stimulated become stronger.

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Best Web Site Name of the Week

The Curious Cat is a blog collecting news on science and engineering — but if the old saw is true, than that poor cat’s days are numbered. Or maybe the cat belongs to Schrodinger, and so exists in a quantum state between life and death, and as such artfully avoids the fate that excessive curiosity would usually visit upon a feline.

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High-efficiency Power Supplies

High-efficiency power supplies for home computers and servers (pdf) by Urs Hoelzle and Bill Weihl – Google:

Most likely, the computer you’re using wastes 30-40% of the electrical power it consumes because it is using an inefficient power supply. It’s difficult to believe that something as basic as a power supply could be responsible for that amount of waste, but it’s true.
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The opportunity for savings is immense — we estimate that if deployed in 100 million PCs running for an average of eight hours per day, this new standard would save 40 billion kilowatt-hours over three years, or more than $5 billion at California’s energy rates.
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The net result of these changes is a dramatic improvement in efficiency (including the power supply and the regulators) to about 85%, at virtually no cost. In other words, you won’t have to pay more for a higher-efficiency PC, because the power supply is actually getting simpler, not more complicated. By spending another $20 or so extra, it is possible to use higher-quality components and achieve efficiencies well over 90%.

Remote-Controlled Submarines

Remote-Controlled Omnidirectional Submarines:

These remote-controlled submarines fit into the palm of your hand and have dual propeller propulsion systems that allow omnidirectional movement underwater in a bathtub, swimming pool, or in shallow ponds. The submarines dive and surface like an actual naval submarine, and the three high-powered motors ensure rapid movement forward, backward, left, right, and while performing 360 progressive rolls. The submarines have dual LED headlights and each unit operates on a unique radio frequency, allowing underwater races with multiple submarines. Includes rechargeable batteries that run for three minutes after a three minute charge.

Fun looking toy. Via: Remote-Controlled Submarines. Related: Science and Engineering Gadgets and Gifts – Lego Autopilot Project Update – Underwater Robots Collaborate

Water Buffaloes, Lions and Crocodiles Oh My

Pretty amazing video. A look at real wild life with lots of excitement, a bit violence and some surprising turns. On my trip to Kenya I saw an interaction between lions and one water buffalo but it was without much of this action. Basically there was a standoff for like half an hour with half charges and the like. Even that was very interesting.

Building Engineering Outside the Box

Helix — a 1D skyscraper with a single corridor:

The principle is a cylindrical building with a helical shape for the floor. The slope of the floor is 1.5% (it rises by 1.5 cm every meter), thus hardly noticeable. The height of each ’storey’ is 3 meters, so that when you walk 200 meters along the corridor, you have walked a full circle, but you end up one ’storey’ above or below your starting point. This results in a diameter of approximately 60 meters, therefore quite common for large skyscrapers. The corridor is on the outside, so that everybody has access to the fabulous views over the city. Offices are all on the inside. As the tower is hollow in the middle, and the inner diameter of the patio is still approximately 40 meters, this makes for a very nice light shaft with peaceful lighting conditions.

The floor of each office is made horizontal, so that your chair does not roll down and hit the separation. But if you take your chair in the corridor, be careful not to let go of it. All things rolling naturally find their way to the lost+found in the lobby.

Ok, this doesn’t seem really practical for a skyscaper but it still is a cool thought experiment. And as they mention it works fine for the Guggenheim Museum in NYC.

Chemistry of Common Items

The American Chemistry Society offers interesting articles on the chemistry of everyday products including: amber, henna, catnip and honey:

To make this delicious treat, foraging bees start out by guzzling nectar, a dilute solution of sugars in flowers. Then, they mix the nectar with enzymes in their stomachlike honey sacs. Back at the hive, the foragers pass the digested material to house bees who reduce the moisture content of the mixture by ingesting and regurgitating it. They then deposit concentrated drops into honeycomb cells. Over the next few days, bees fan the fluid with their wings to further concentrate it, and finally, they cap the cells with wax. At the same time, enzyme-mediated changes produce a range of sugars and acids in the honey.

Bee enzymes also show up in the finished product. Invertase is the most critical. It splits the sucrose in the nectar into fructose and glucose and also produces some erlose. Another enzyme, glucose oxidase, converts glucose to gluconolactone, which is then hydrolyzed to give gluconic acid, the principal acid in honey. Formic, acetic, butyric, and lactic acids are also found in honey, which explains why its pH typically measures 3.8-4.0 and bacteria have a hard time growing in it.

Engineering, Math and Physics Applets

Java applets illustrating concepts in math, physics and engineering including: Coupled Oscillations, Digital Filters, 3-D Magnetostatic Fields and Ordinary Differential Equations.