抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Current research into semiconductor clusters is focused on the properties of quantum dots-fragments of semiconductor consisting of hundreds to many thousands of atoms-with the bulk bonding geometry and with surface states eliminated by enclosure in a material that has a larger band gap. Quantum dots exhibit strongly size-dependent optical and electrical properties. The ability to join the dots into complex assemblies creates many opportunities for scientific discovery.

Semiconductor Clusters, Nanocrystals, and Quantum Dots

Titanium Dioxide Nanomaterials: Synthesis, Properties, Modifications, and Applications

/pdf/self-assembled-monolayers-of-thiolates-on-metals-as-a-form-1neb0hj3k4.pdf

Self-assembled monolayers of thiolates on metals as a form of nanotechnology.

Highly luminescent semiconductor quantum dots (zinc sulfide-capped cadmium selenide) have been covalently coupled to biomolecules for use in ultrasensitive biological detection. In comparison with organic dyes such as rhodamine, this class of luminescent labels is 20 times as bright, 100 times as stable against photobleaching, and one-third as wide in spectral linewidth. These nanometer-sized conjugates are water-soluble and biocompatible. Quantum dots that were labeled with the protein transferrin underwent receptor-mediated endocytosis in cultured HeLa cells, and those dots that were labeled with immunomolecules recognized specific antibodies or antigens.

http://science.sciencemag.org/content/sci/281/5385/2016.full.pdf

Quantum Dot Bioconjugates for Ultrasensitive Nonisotopic Detection

Hydrodeoxygenation (HDO) of 2-acetylfuran (2-AF) was examined at 473 K and 33 bar over carbon-supported, bimetallic catalysts. Monodispersed, Pt-based (PtNi, PtCo, and PtCu) and Ni-based (NiCu) nanocrystals (NCs) with well-defined sizes and compositions were prepared via colloidal synthesis. Steady-state, flow-reactor measurements demonstrate that selectivities for HDO reaction to 2-ethylfuran (2-EF) are strongly dependent on the alloy compositions. The HDO of 2-AF is shown to be sequential, where 2-EF can react further to form over-hydrogenated products. The NiCu3/C nanocatalyst was superior to the other bimetallics; with the optimal residence time, it achieved a selectivity of 75 % 2-EF with 80 % conversion of 2-AF, with good stability for up to at least five hours time-on-stream. Deactivation due to coking became an issue when the NCs were deposited on oxide supports with weak acidity (SiO2 and γ-Al2O3). This work provides insights into which bimetallic catalytic systems might be useful for HDO of 2-AF reaction.

Engineering the composition of bimetallic nanocrystals to improve hydrodeoxygenation selectivity for 2-acetylfuran

Microdroplets made from chiral liquid crystals (CLCs) can display reflective structural colors. However, the small area of reflection and their isotropic shape limit their performance. Here, Janus microdroplets are synthesized through phase separation between CLCs and silicone oil. The as‐synthesized Janus microdroplets show primary structural colors with ≈14 times larger area compared to their spherical counterparts at a specific orientation; the orientation and thus the colored/transparent states can be switched by applying a magnetic field. The color of the Janus microdroplets can be tuned ranging from red to violet by varying the concentration of the chiral dopant in the CLC phase. Due to the density difference between the two phases, the Janus microdroplets prefer to orientate the silicone oil side up vertically, enabling the self‐recoverable structural color after distortion. The Janus microdroplets can be dispersed in aqueous media to track the configuration and speed of magnetic objects. They can also be patterned as multiplexed labels for data encryption. The magnetic field‐responsive Janus CLC microdroplets presented here offer new insights to generate and switch reflective colors with high color saturation. It also paves the way for broader applications of CLCs, including anti‐counterfeiting, data encryption, display, and untethered speed sensors.

Janus Microdroplets with Tunable Self‐Recoverable and Switchable Reflective Structural Colors

Electrons traverse two-dimensional nanocrystal arrays by sequential tunneling between neighboring nanocrystals. Analysis of array conductance at zero bias-voltage gives information about underlying nanocrystal uniformity, as well as the relevant single-electron charging energy. We discuss low-temperature measurements of two-dimensional self-assembled superlattices composed of 10 nanometer diameter cobalt nanocrystals, with ~2 nm inter-nanocrystal spacing.

Low-Voltage Electron Transport in Self-Assembled Nanocrystal Arrays

We demonstrate micro-photoluminescence measurements of PbS nanocrystals coupled to air-slot mode-gap photonic crystal nanocavities with Q∼15,000 and V eff ∼0.02 (λ/n air )3. The ultrahigh Q/V ratios are critical for applications in cavity QED, nonlinear optics and sensing.

Weak exciton-photon coupling of PbS nanocrystals in air-slot mode-gap Si photonic crystal nanocavities in the near-infrared

Self-assembled superparticles composed of colloidal quantum dots establish microsphere cavities that support optically pumped lasing from whispering gallery modes. Here, we report on the time- and excitation fluence-dependent lasing properties of CdSe/CdS quantum dot superparticles. Spectra collected under constant photoexcitation reveal that the lasing modes are not temporally stable but instead blue-shift by more than 30 meV over 15 min. To counter this effect, we establish a high-fluence light-soaking protocol that reduces this blue-shift by more than an order of magnitude to 1.7 ± 0.5 meV, with champion superparticles displaying mode blue-shifts of <0.5 meV. Increasing the pump fluence allows for optically controlled, reversible, color-tunable red-to-green lasing. Combining these two paradigms suggests that quantum dot superparticles could serve in applications as low-cost, robust, solution-processable, tunable microlasers.

Christopher B. Murray

Papers

Engineering the composition of bimetallic nanocrystals to improve hydrodeoxygenation selectivity for 2-acetylfuran

Janus Microdroplets with Tunable Self‐Recoverable and Switchable Reflective Structural Colors

Low-Voltage Electron Transport in Self-Assembled Nanocrystal Arrays

Weak exciton-photon coupling of PbS nanocrystals in air-slot mode-gap Si photonic crystal nanocavities in the near-infrared

Frequency Stabilization and Optically Tunable Lasing in Colloidal Quantum Dot Superparticles.