ie8 fix

Science and biotech

High-tech 'fertility chip' measures sperm count, motility

If you'd like a better understanding of what it takes for sperm to be considered fertile, go grab your measuring spoons and look at the quarter teaspoon. Roughly that amount of ejaculate should boast anywhere between 20 million and 150 million sperm. Anything less than 20 million and fertility just might be an issue.

So Loes Segerink, a researcher at the University of Twente in the Netherlands, has developed a "fertility chip" that can accurately count one's sperm concentration as well as measure its mobility (when discussing sperm the synonym "motility" is often used). What's more, the test can be taken at home, with the ejaculate being, ahem, collected in a more private environment.

While simple home tests are already commercially available, the concentration readings are, well, simple, and indicate only whether sperm concentration is above or below that 20 million mark. But one man's sperm concentration of 19 million is certainly more fertile than another man's count of 1 million.

Segerink, who will be defending her doctoral dissertation in November, says the sperm flows past a liquid-filled channel on the chip beneath electrode "bridges." When cells pass beneath these bridges, a brief fluctuation in electrical resistance occurs. By counting these events, the chip is counting sperm.… Read more

Venter introduces X Prize to sequence centenarians' DNA

What does it take to make it to 100 years old? The Archon Genomics X Prize hopes to find out.

As I've researched "extreme" aging in recent years--that is, the genes and lifestyles of centenarians (100 and older) and supercentenarians (110 and older)--a common refrain I hear from my younger peers is, "I don't want to get that old. It sounds miserable."

Whether or not that's true is something most of us will never find out. The reality is that those who make it past 100 are an exceedingly rare breed of … Read more

Skin-like sensor flexible enough for prosthetic limbs

Researchers at Stanford are developing new sensors so flexible and pressure-sensitive that they could be used to make touch-sensitive prosthetic limbs, pressure-sensitive badges, and more.

By incorporating a transparent film of carbon nano-springs, the sensor "can register pressure ranging from a firm pinch between your thumb and forefinger to twice the pressure exerted by an elephant standing on one foot," says postdoctoral researcher Darren Lipomi, co-author of a paper published October 23 in the journal Nature Nanotechnology. "None of it causes any permanent deformation."

The team built those nano-springs by airbrushing nanotubes (which are in liquid … Read more

Playing molecular Legos with viruses

It may be benign, but researchers have turned the virus M13 into a sophisticated engineering tool that could lead to the manufacturing of materials with biomedical properties that can be fine-tuned, such as bone, skin, and corneas.

"We took our inspiration from nature," said Seung-Wuk Lee, an associate professor of bioengineering at UC Berkeley who describes the team's self-templating material assembly process in the journal Nature. "Nature has a unique ability to create functional materials from very basic building blocks. We found a way to mimic [this]."

Lee points to the protein collagen as the … Read more

Human-powered: Biofuel cell converts glucose into electricity

As scientists unveil artificial organs and prosthetics to improve the function of our hearts, kidneys, hands, and even eyes, it's easy to gloss over these devices' Achilles' heel: power.

Even building devices that run on very low power, such as pacemakers, tend to require additional invasive surgeries just to replace their batteries. Meanwhile, artificial limbs can be huge energy hogs, with the power source needing to be swapped out as frequently as every few weeks. Impractical is an understatement.

Biofuel cells could very well solve this problem. Researchers around the world are investigating how to use a body's own energy to power various devices, and one team out of France last year successfully implanted in a rat a biofuel cell that uses glucose and oxygen to generate electricity.… Read more

Ick! Researchers find E. coli on 1 in 6 cell phones

In 12 cities across England this past spring, researchers took almost 400 samples from cell phones and hands on the hunt for bacteria.

The researchers--from the London School of Hygiene and Tropical Medicine and Queen Mary, University of London--found that 16 percent of both the phones and hands contained E. coli, a form of bacteria that inhabits our intestines and is typically spread through fecal matter.

At 400, the sample size is by no means large, but if those percentages are accurate, there is simply no getting around the conclusion: traces of our own poop and the resulting bacteria are hanging out on 1 in 6 of our phones and hands.… Read more

Caltech's ePetri dish uses Android, not microscope

What do you get when you combine an Android smartphone, cell phone image sensor, Lego building blocks, and a handful of Caltech engineers and biologists? The ePetri, which isn't Petri Dish 2.0, but a full reworking of a technology that dates back to the late 1800s.

Traditionally, the Petri dish (named after German bacteriologist Julius Richard Petri) has been used in the medical field to identify bacterial infections by studying samples via microscope as the cultured cells grow in an incubator.

The Caltech researchers have a few choice words for such an approach in 2011, including "expensive," "labor-intensive," and "suboptimal." So they set out to improve not just the dish, but the entire process.… Read more

Millions of tweets reveal global mood trends

It may not be terribly surprising that many of us find our moods dipping over the course of the day, and that by nightfall we light up again. Or that our moods are perkiest on weekends, regardless of which days our weekends fall on (i.e., Fridays and Saturdays in the United Arab Emirates).

What's of note, according to an analysis of 2.4 million tweets in 84 countries by researchers out of Cornell, is that these mood trends hold steady across cultures and borders, hinting at some sort of deeper trend whose basis is in being human, not … Read more

Engineers harness power from human respiration

The airflow of a typical human breath travels at less than 2 meters per second. Instead of lamenting its weakness, engineers at the University of Wisconsin-Madison decided to try to make a material that could react to this airflow in such a way as to convert it to electrical energy.

So they turned to polyvinylidene fluoride (PVDF), a material in which an electrical charge can build up in response to applied mechanical stress. (There's even a name for this: the piezoelectric effect.) The trick, then, was to get this material thin enough to be sufficiently stressed by human breath.

"We calculated that if we could make this material thin enough, small vibrations could produce a microwatt of electrical energy that could be useful for sensors or other devices implanted in the face," says Xudong Wang, a materials science and engineering assistant professor who reports on these findings in the journal Energy & Environmental Science.

Wang's team had go about thinning this material very carefully, so as to preserve its piezoelectric properties. They used an ion-etching process that, with some improvements, might eventually enable them to control thickness to the submicron level.

The obvious benefits of using respiration to power biomedical devices (think blood glucose monitors or pacemakers) are that the source is local and it is consistent.… Read more

New cloth self-cleans by killing bacteria

Tossing clothes into the wash when dirty is so last year, thanks to a discovery by chemists out of the University of California at Davis. Near-ordinary cotton may simply need be exposed to light to get busy killing bacteria and breaking down toxic chemicals such as pesticide residues.

Ning Liu, a doctoral student at UC Davis, worked with textile chemists Gang Sun and Jing Zhu to develop a method that incorporates a compound (2-AQC) into cotton fabrics. When exposed to light, it produces reactive oxygen species such as hydrogen peroxide that kill bacteria and break down toxins.

While Liu says 2-AQC is more expensive than other compounds, it is difficult to remove from cotton due to strong bonding, and cheaper equivalents should work, too.

"The new fabric has potential applications in biological and chemical protective clothing for health care, food processing, and farm workers, as well as military personnel," she says.

The team reported on its findings in the Journal of Materials Chemistry last month, shortly before another study out of the University of Iowa chronicled the vast presence of even drug-resistant disease-causing bacteria on hospital curtains.… Read more