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A plastic plan for organic synthesis

czw., 2018-01-18 20:23

Watching single molecules in motion

czw., 2018-01-18 20:23

A global map of soil bacteria

czw., 2018-01-18 20:23

A naturally modified cellulose

czw., 2018-01-18 20:23

Regeneration circuits in the thymus

czw., 2018-01-18 20:23

Going dry in the Pacific Northwest

czw., 2018-01-18 20:23

Time-out for mRNAs in the nucleus

czw., 2018-01-18 20:23

Serious damage by soluble tau

czw., 2018-01-18 20:23

Lighting up riboswitching

czw., 2018-01-18 20:23

The value of scaffolds

czw., 2018-01-18 20:23

Social skills to pay the bills

czw., 2018-01-18 20:23

Genome-wide identification of interferon-sensitive mutations enables influenza vaccine design

czw., 2018-01-18 20:23

In conventional attenuated viral vaccines, immunogenicity is often suboptimal. Here we present a systematic approach for vaccine development that eliminates interferon (IFN)–modulating functions genome-wide while maintaining virus replication fitness. We applied a quantitative high-throughput genomics system to influenza A virus that simultaneously measured the replication fitness and IFN sensitivity of mutations across the entire genome. By incorporating eight IFN-sensitive mutations, we generated a hyper–interferon-sensitive (HIS) virus as a vaccine candidate. HIS virus is highly attenuated in IFN-competent hosts but able to induce transient IFN responses, elicits robust humoral and cellular immune responses, and provides protection against homologous and heterologous viral challenges. Our approach, which attenuates the virus and promotes immune responses concurrently, is broadly applicable for vaccine development against other pathogens.

A self-assembled nanoscale robotic arm controlled by electric fields

czw., 2018-01-18 20:23

The use of dynamic, self-assembled DNA nanostructures in the context of nanorobotics requires fast and reliable actuation mechanisms. We therefore created a 55-nanometer–by–55-nanometer DNA-based molecular platform with an integrated robotic arm of length 25 nanometers, which can be extended to more than 400 nanometers and actuated with externally applied electrical fields. Precise, computer-controlled switching of the arm between arbitrary positions on the platform can be achieved within milliseconds, as demonstrated with single-pair Förster resonance energy transfer experiments and fluorescence microscopy. The arm can be used for electrically driven transport of molecules or nanoparticles over tens of nanometers, which is useful for the control of photonic and plasmonic processes. Application of piconewton forces by the robot arm is demonstrated in force-induced DNA duplex melting experiments.

Quantum liquid droplets in a mixture of Bose-Einstein condensates

czw., 2018-01-18 20:23

Quantum droplets are small clusters of atoms self-bound by the balance of attractive and repulsive forces. Here, we report on the observation of droplets solely stabilized by contact interactions in a mixture of two Bose-Einstein condensates. We demonstrate that they are several orders of magnitude more dilute than liquid helium by directly measuring their size and density via in situ imaging. We show that the droplets are stablized against collapse by quantum fluctuations and that they require a minimum atom number to be stable. Below that number, quantum pressure drives a liquid-to-gas transition that we map out as a function of interaction strength. These ultradilute isotropic liquids remain weakly interacting and constitute an ideal platform to benchmark quantum many-body theories.