Chemistry – Little Bits of Science

Repelling Mosquitoes. Or Not.

So all those gadgets and candles you use for getting rid of mosquitoes? Mostly worthless, it seems.

A large number of different spray-on repellents and wearable repellent devices are commercially available. The efficacies of many repellents are unknown. This study focuses on the efficacy of eleven different repellents in reducing the number of Ae. aegypti female mosquitoes attracted to human bait. We performed attraction-inhibition assays using a taxis cage in a wind tunnel setting. One person was placed upwind of the taxis cage and the mosquito movement towards or away from the person was recorded. The person was treated with various spray-on repellents or equipped with different mosquito repellent devices.

The most effective repellent was a DEET-based product. And least effective were devices which use high-frequency sound to keep mosquitoes away. Link found via ScienceMag.

Bees are Addicted to Caffeine

I’m a big fan of caffeine. So much so that I have a caffeine molecule tattooed on my left forearm. caffeine photo But it turns out that humans aren’t the only caffeine aficionados. Bees like caffeine, and spend more time gathering nectar from flowers which naturally produce caffeine.

Scientists at the University of Sussex said they thought the plants produce the caffeine in their nectar to fool bees into thinking it contains more sugar than it actually does. The insects will repeatedly visit those flowers, helping the plants maximize pollination.

Francis Ratnieks, a professor of apiculture at the university, said bees communicate by moving their abdomens a certain way — or, as he calls it, “dancing.” He said the caffeine increases that dancing.

Photo by Hey Paul Studios

Photo by paulscott56

Caffeine and Miscarriage Risk

I love my caffeine. So much so that I got a tattoo of the molecule on my arm. That said, people need to be aware of the potential risks.

A new study conducted by the National Institutes of Health (NIH) suggests couples who consume more than two caffeinated beverages daily in the weeks leading up to conception may have an increased risk of miscarriage. The research, conducted with authors at the Ohio State University, similarly found women who drank more than two daily caffeinated beverages during the first seven weeks of pregnancy saw an increased miscarriage risk. Previous studies have drawn similar links, but researchers hadn’t been able to single out caffeine as a particular culprit.

So while the benefit of caffeine is really great, it’s not all fun and games. Exercise caution – moderate your intake, and consider doing without during the pregnancy.

Women in Science – Dr. Maud L. Menten

To start my Women in Science series, I’ll present information on a scientist with whom I share a birthday – Dr. Maud L. Menten, Biochemist from Canada. Born in Port Lambton, Ontario in 1879, Dr. Menten graduated from the University of Toronto in 1913 (some sources say 1911). Later in 1913, she was an author for the article “Die Kinetik der Invertinwirkung” which introduced the Michaelis-Menten equation, used to relate the reaction rate of an enzyme to the concentration of a substrate.

The reaction rate increases with increasing substrate concentration $[S]$ , asymptotically approaching its maximum rate $V_\max$ , attained when all enzyme is bound to substrate. It also follows that $V_\max = k_\mathrm{cat} [E]_0$ , where $[E]_0$ is the initial enzyme concentration. $k_\mathrm{cat}$ , the turnover number, is the maximum number of substrate molecules converted to product per enzyme molecule per second.

Her contributions to science continued long after the Michaelis-Menten equation. She made additional discoveries/co-discoveries relating to hemoglobin, blood sugar, and kidney functions. Because women were not generally able to work in the medical field in Canada at the time, she ended up working mainly in the US with some time spent in Europe, as well.

Dr. Menten continues to be honored today by the Dr. Maud L. Menten Memorial Lecture Series.

The Dr. Maud L. Menten Memorial Lecture Series is held annually by the Department of Biochemistry. Two mini-symposia and at least eight lectures will be held each year. The speakers are expected to be active, high-profile scientists and are nominated by the Department of Biochemistry research community. Invitations are sent after selection of the speakers by the Dr. Maud L. Menten Memorial Lecture Series Committee.

Budget Problems Could Lead to Berkeley College of Chemistry Shutdown

While emphasizing there are no firm plans in place yet, there is talk at Berkeley of shutting down the College of Chemistry in order to help with budget problems the school is facing. berkeley chemistry photo There is also a petition by the student body to not do this.

The College of Chemistry was established in 1872. In the 20th century, researchers in the college at the Lawrence Berkeley National Laboratory discovered nine elements now on the periodic table. Today, the college is known as a pioneer in traditional and emerging fields of chemistry.

By Thursday evening, Melville’s petition, which addresses Chancellor Nicholas Dirks, had gained more than 1,800 signatures — more than the College of Chemistry’s undergraduate population.

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