Nature: The human immune system poses one of the biggest challenges to the delivery of drugs to diseased areas of the body because its macrophages target and destroy foreign molecules. Now Dennis Discher of the University of Pennsylvania and his colleagues believe they have found a solution—attaching “safe” peptides to the drug-delivery molecules. Discher’s team used computer simulations to design a small, 21-amino-acid peptide based on the structure of CD47, a membrane protein that macrophages recognize as safe. They then attached the peptide to dye-carrying nanobeads of polystyrene and injected them into mice, along with an equal number of beads not containing the peptide. Using fluorescent spectroscopy to compare their movement through the mice’s bloodstream, the researchers found that four times as many of the altered nanobeads got past the macrophage defenses. They also determined that the nanoparticles tended to cluster in tumors. Adding the anticancer drug paclitaxel to the nanobeads shrank the tumors just as effectively as the traditional paclitaxel delivery system, Cremophor, but without the side effects.
Ars Technica: In 2007, researchers manipulated the waveforms of photons in beams of light to prevent the light from diffracting as it passed through the air. Now, beams of electrons have been similarly manipulated. Noa Voloch-Bloch of Tel Aviv University in Israel and her colleagues passed the electrons through a holographic pattern created by a magnetic field. The hologram, which acted as a lens, allowed the researchers to alter the waveforms of the electrons. The careful tuning of the waveforms caused the electrons to interfere with each other in a way that forced them to follow a parabolic path instead of diffracting. That result is known as an Airy beam. One of the unique characteristics of an Airy beam is that if it encounters something that partially blocks its path, the beam will pass by the object as if the barrier was not there. The ability to focus electron beams in this way may be useful for electron microscopes and for studying the properties of electrons themselves.
New York Times: The most recent report of the International Atomic Energy Agency concerning Iran’s nuclear development says that Iran has begun installing advanced centrifuge machines at its nuclear plant at Natanz. The centrifuges are 4–5 times more powerful than previous ones. Although the US, Israel, and Europe fear Iran is expanding its weapons technology, Iran maintains that it is refining uranium for nuclear power only. The subject will be discussed next week during Iran’s first nuclear talks with the West since last summer.
Science: Since the 1920s the Turkish constitution has banned the wearing of headscarves by women who work in the public sector. However, the ban has always been controversial, and since 2003 Turkey’s government has been dominated by a moderate Islamic political party, the Justice and Development Party. Now a senior astrophysics professor could go to prison for preventing female students wearing scarves from attending his class. Rennan Pekünlü, who teaches at Ege University in Izmir, claims he was upholding the Turkish constitution. Nevertheless, he was found guilty last September of violating the rights of women and faces 25 months in prison unless he wins his appeal next month. And he is not the only secularist academic having problems. In June of last year, Kemal Gürüz, the former head of Turkey’s Council of Higher Education and a prominent academic reformer, was arrested; Gürüz remains in prison.