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

We measured the elastic properties and intrinsic breaking strength of free-standing monolayer graphene membranes by nanoindentation in an atomic force microscope. The force-displacement behavior is interpreted within a framework of nonlinear elastic stress-strain response, and yields second- and third-order elastic stiffnesses of 340 newtons per meter (N m(-1)) and -690 Nm(-1), respectively. The breaking strength is 42 N m(-1) and represents the intrinsic strength of a defect-free sheet. These quantities correspond to a Young's modulus of E = 1.0 terapascals, third-order elastic stiffness of D = -2.0 terapascals, and intrinsic strength of sigma(int) = 130 gigapascals for bulk graphite. These experiments establish graphene as the strongest material ever measured, and show that atomically perfect nanoscale materials can be mechanically tested to deformations well beyond the linear regime.

/pdf/measurement-of-the-elastic-properties-and-intrinsic-strength-27nythtm75.pdf

Measurement of the Elastic Properties and Intrinsic Strength of Monolayer Graphene

Single-layer metal dichalcogenides are two-dimensional semiconductors that present strong potential for electronic and sensing applications complementary to that of graphene.

/pdf/electronics-and-optoelectronics-of-two-dimensional-2jbqr1unvw.pdf

Electronics and optoelectronics of two-dimensional transition metal dichalcogenides.

We report the measurement of the thermal conductivity of a suspended single-layer graphene. The room temperature values of the thermal conductivity in the range ∼(4.84 ± 0.44) × 103 to (5.30 ± 0.48) × 103 W/mK were extracted for a single-layer graphene from the dependence of the Raman G peak frequency on the excitation laser power and independently measured G peak temperature coefficient. The extremely high value of the thermal conductivity suggests that graphene can outperform carbon nanotubes in heat conduction. The superb thermal conduction property of graphene is beneficial for the proposed electronic applications and establishes graphene as an excellent material for thermal management.

/pdf/superior-thermal-conductivity-of-single-layer-graphene-2op5i6aw2y.pdf

Superior Thermal Conductivity of Single-Layer Graphene

Many potential applications have been proposed for carbon nanotubes, including conductive and high-strength composites; energy storage and energy conversion devices; sensors; field emission displays and radiation sources; hydrogen storage media; and nanometer-sized semiconductor devices, probes, and interconnects. Some of these applications are now realized in products. Others are demonstrated in early to advanced devices, and one, hydrogen storage, is clouded by controversy. Nanotube cost, polydispersity in nanotube type, and limitations in processing and assembly methods are important barriers for some applications of single-walled nanotubes.

http://science.sciencemag.org/content/sci/297/5582/787.full.pdf

Carbon Nanotubes--the Route Toward Applications

We examine the resistivity and thermopower of single crystal specimens of the pyrochlore oxide Cd 2 Re 2 O 7 at pressures up to 2 GPa Thermopower proves to be a sensitive tool in the study of the phase diagram of Cd 2 Re 2 O 7  The 200 K metal-to-metal phase transition is accompanied by a strong increase of the absolute value of the thermopower A weaker anomaly allows us to identify a second phase transition at 125 K Following the temperature dependence of this anomaly, we obtain the corresponding phase boundary up to 12 GPa, and argue that it must drop to T=0 before p reaches 18 GPa There is a wide temperature range where the electrical properties are fairly sensitive to pressure, indicating the strong coupling of the electronic degrees of freedom to the lattice

Electrical properties of Cd2Re2O7 under pressure

The three-dimensional trap stiffness of optical tweezers formed with high-NA micromirrors is investigated by back-focal-plane interferometry and power spectrum analysis. Normalized stiffness values of κxy/Ptrap=1.2(μN/m)/mW and κz/Ptrap=0.52(μN/m)/mW in the transverse and axial directions, respectively, have been measured for polystyrene spheres with a radius of 1.03 μm. Compared with high-NA microscope objectives, micromirrors achieve much better trapping performances, particularly in the axial direction.

/pdf/three-dimensional-force-measurements-in-optical-tweezers-3bt0hi2dlz.pdf

Three-dimensional force measurements in optical tweezers formed with high-NA micromirrors

The metallic phase of the organic conductor TMTSF -DMTCNQ stabilized by a weak irradiation disorder

Based on the reported ion migration under electric field in hybrid lead halide perovskites we have developed a bright, light emitting electrochemical cell with CH3NH3PbBr3 single crystals directly grown on vertically aligned carbon nanotube (VACNT) forests as contact electrodes. Under the applied electric field, charged ions in the crystal drift and accumulate in the vicinity of the electrodes, resulting in an in operando formed p-i-n heterojunction. The decreased interface energy barrier and the strong charge injection due to the CNT tip enhanced electric field, result in a bright green light emission up to 1800 cd/m2 at room temperature (average = 60 cd/m2). Beyond the light emission, this original device architecture points to the possibility of implementing vertically aligned CNTs as electrodes in operationally-stable perovskite-based optoelectronic devices.

/pdf/light-emitting-electrochemical-cells-of-single-crystal-1yellklvuk.pdf

Light-Emitting Electrochemical Cells of Single Crystal Hybrid Halide Perovskite with Vertically Aligned Carbon Nanotubes Contacts

We report a comprehensive study of transport, magnetotransport, and magnetic properties of single crystals of BaVSe3. The paramagnetic metal-ferromagnetic metal transition at 43 K was followed as a function of pressure by measuring the electrical resistivity and the thermoelectric power. The exponent of the low-temperature power-law dependence of the resistivity increases with pressure. The effective magnetic moment obtained from magnetic susceptibility in the paramagnetic regime is mu(eff)=1.40 mu(B). The study was completed by band-structure calculations based on density-functional theory both at ambient and high pressures. Transport coefficients of BaVSe3 resemble the high-pressure phase of BaVS3, which suggest that the replacement of sulfur with selenium can be viewed as chemical pressure.

/pdf/transport-and-magnetic-properties-of-bavse3-3p23fl9jkx.pdf

László Forró

Papers

Electrical properties of Cd2Re2O7 under pressure

Three-dimensional force measurements in optical tweezers formed with high-NA micromirrors

The metallic phase of the organic conductor TMTSF -DMTCNQ stabilized by a weak irradiation disorder

Light-Emitting Electrochemical Cells of Single Crystal Hybrid Halide Perovskite with Vertically Aligned Carbon Nanotubes Contacts

Transport and magnetic properties of BaVSe3