Ticks transmit more pathogens to humans and animals than any other arthropod. We describe the 2.1 Gbp nuclear genome of the tick, Ixodes scapularis (Say), which vectors pathogens that cause Lyme disease, human granulocytic anaplasmosis, babesiosis and other diseases. The large genome reflects accumulation of repetitive DNA, new lineages of retro-transposons, and gene architecture patterns resembling ancient metazoans rather than pancrustaceans. Annotation of scaffolds representing ∼57% of the genome, reveals 20,486 protein-coding genes and expansions of gene families associated with tick–host interactions. We report insights from genome analyses into parasitic processes unique to ticks, including host ‘questing', prolonged feeding, cuticle synthesis, blood meal concentration, novel methods of haemoglobin digestion, haem detoxification, vitellogenesis and prolonged off-host survival. We identify proteins associated with the agent of human granulocytic anaplasmosis, an emerging disease, and the encephalitis-causing Langat virus, and a population structure correlated to life-history traits and transmission of the Lyme disease agent.

Addition of nanoclays or other nanoparticles into various polymers to produce nanocomposites has been extensively utilized in an attempt to enhance the mechanical, physical, and thermal properties of polymers. While some interesting properties have been demonstrated, the resulting nanocomposites have yet to realize their full potential. Nanoparticles in general, and nanoclays in particular, with their nanometer size, high surface area, and the associated predominance of interfaces in the nanocomposites, can function as structure and morphology directors, for example stabilizing a metastable or conventionally inaccessible polymer phase, or introduce new energy dissipation mechanisms. Thus, what distinguishes nanoparticles from conventional micrometer-size rigid reinforcements is that their role might not be limited to only adding stiffness to the polymer, but also to directing morphology, as well as introducing new energy-dissipation mechanisms leading to enhanced toughness in the nanocomposites. Herein we demonstrate this potential by reporting a remarkable (order of magnitude) increase in toughness with a concurrent increase in stiffness in a poly(vinylidene fluoride) (PVDF) nanocomposite.The kinetics of crystallite growth and the details of crystallite morphology of semicrystalline polymers can be affected by the presence of layered silicates. [1,2] Although some changes in morphology have been described in polymer/nanoparticle hybrids, [3±7] near-total stabilization and control of a crystalline phase, coupled with dramatic enhancements in materials properties, has not yet been reported. PVDF is an important engineering plastic. It is used extensively in the pulp and paper industry due to its resistance to halogens and acids, in nuclear-waste processing for radiation-, and hot-acid applications, and in the chemical processing industry for chemical and high-temperature applications. It is also used in various device applications, due to its unique piezoelectric [8±10] and pyroelectric [11] properties. There are five known crystalline forms or polymorphs of PVDF: a, b, c, d, and e.[12] The a phase is the most common in melt crystallization, and remains the dominant crystalline form versus the b, and c phases. The c phase does not form except at high temperatures and pressures. Earlier reports have shown that the a phase (chain conformationÐtrans-gauche trans-gauche, tgis inactive with respect to piezo-and pyroelectric properties, while the b form (all trans) exhibits the most activity, and is thus the focus for electromechanical and electroacoustic transducer applications. Thus, the b form has great technological utility and there have been numerous attempts to stabilize this phase. For example, the b form of the PVDF has been obtained by careful crystallization from solution, [13] by melt crystallization at high pressure, by application of a strong electric field, [14] by molecular epitaxy, [15] and by preparing a carbon-coated, highly oriented ultrathin film.[16] Earlier reports have indicated the possibility...

Surface engineering of nanoparticles has fueled the evolution of nanoscience and nanotechnology through the design of new functional materials with novel electronic, magnetic, optical, and biological properties. Depending on the surface modifier, which can vary from a simple molecule to a complex biomolecule, nanoparticles with a range of functional properties and potential applications can be produced.[1±6] In all these instances, in the absence of any solvent the functionalized nanoparticles appear and behave in a solid-like manner.In the present communication, we describe a novel family of functionalized nanoparticles that exhibit liquid-like behavior in the absence of any solvent. Surface modification of silica or maghemite (c-Fe 2 O 3 ) nanoparticles with a charged organosilane moiety renders the resulting hairy nanoparticles cationic. A counterion is typically present to balance the charge on the nanoparticles (henceforth described as nanosalts), as shown in Figure 1. Depending on the nature of the counterion, it is possible to isolate the nanosalts in liquid form, even at room temperature. These hybrid nanoparticles represent a unique class of solvent-free colloids that are distinguished from conventional colloidal suspensions in a solvent. Their fluidity in the absence of any solvent and zero vapor pressure offers significant new scientific and technological opportunities. For instance, such systems can address some environmental concerns associated with solid nanoparticles. They can also provide a better means to process nanoparticles into films or other functional forms. In addition, they can offer new, solvent-free conducting, magnetic, or electrorheological fluids, among others. Lastly, space restrictions imposed by the dimensions of the nanoparticles, in conjunction with their intrinsic physicochemical properties, make this class of materials particularly attractive as new reaction media.Silica nanoparticles (diameter 7 nm) were modified by condensation of (CH 3 (R = alkyl chain) to obtain the corresponding nanosalts. When chloride is the counter anion, the nanosalt is isolated in a powder form. No melting is observed even after heating to 150 C, above the surface decomposition temperature of the organic-surface modifier. In contrast, replacement of the chloride by R(OCH 2 CH 2 ) 7 O(CH 2 ) 3 SO 3 ± ions yields a clear liquid at room temperature (Fig. 2a). The liquid-like nature of the nanosalt is demonstrated by its ability to dissolve the polar dye methylene blue as a common solvent would. Non-polar dyes (e.g., coumarin derivatives) can also be dissolved in the nanosalt, affording transparent, colored liquids. Furthermore, we were able to dissolve and polymerize pyrrole to form polypyrrole in the nanosalt medium (Fig. 2b). The high organic content of the material (vide infra), nanometer size, and density of the silica all play a key role in producing the liquid nanosalt. The differential scanning calorimetry (DSC) profile of the sulfonate nanosalt shows a reversible first-order endothermic phase ...

In the past decade, attention has been focused on using polymer nanocomposites to overcome the trade-offs encountered in traditional composite systems.[1±12] Notwithstanding an increase in stiffness, most reported nanocomposites exhibit lower toughness than the matrix polymers, although Cohen and co-workers have found that some particulate-filled polymer composites show an increase in toughness compared to the neat polymer.[13±15] They attributed the effect to the combined mechanisms of crack deflection and local plastic deformation of the polymer around the particles following debonding. Recent work in our group has led to the development of nanohybrid materials, more specifically poly(vinylidene fluoride) (PVDF) nanocomposites, that exhibit a simultaneous increase in stiffness and toughness. The new nanocomposites are almost an order of magnitude tougher than the pure polymer. Recent molecular-dynamics studies have suggested that the mobility of the nanoparticles in the polymer might be crucial for introducing new energy-dissipating mechanisms that lead to enhanced toughness in the nanocomposite.[16] We present experimental evidence that nanoparticle orientation and alignment under tensile stress is responsible for this energydissipation mechanism. This mechanism is applicable to both semicrystalline and amorphous systems and is typically absent from conventional polymer composites. The response measured below and above the polymer glass-transition temperature (T g ) indicates that mobility of the polymer matrix is a precondition for this mechanism to be effective. In other words, the increase in toughness scales with the increase in the mobility of the polymer chains, which in turn dictates the mobility of the nanoparticles. Our results show that, although the degree of improvement in toughness is system dependent, nonetheless an increase can be induced across a broad range of polymer systems and morphologies. Semicrystalline PVDF and amorphous atactic polystyrene (PS) nanocomposites containing 5 wt.-% of nanoparticles (nanoclay) were synthesized via melt extrusion. X-ray and transmission electron microscopy (TEM) analysis of both systems confirmed the presence of a homogenous nanometer-scale dispersion of multilayers of alternating polymer and nanoclay stacks. Both systems showed an intercalated nanostructure. Thermal analysis in the form of dynamic mechanical analysis and differential scanning calorimetry showed no evidence of a change in either the degree of crystallinity for the PVDF nanohybrid or of the T g for both the PVDF and PS nanocomposites. The nanohybrids were then subjected to tensile testing at a strain rate of 5 mm min ±1 at different temperatures to measure the change in the response of the nanohybrids compared with the pure polymers. Figure 1 summarizes the results. From Figure 1a, it can be seen that at 30 C (the T g of PVDF is ±40 C), there is an order-of-magnitude increase (~700 %) in the toughness of the nanohybrid as measured by

Recently, we have developed a novel family of functionalized nanostructures that exhibit liquid‐like behavior in the absence of solvents and preserve their nanostructure in the liquid state. The gallery of nanostructures developed so far includes functionalized silica and magnetic iron oxide nanoparticles, layer‐like organosilicate nanoparticles, polyoxometalate clusters, and organic–inorganic hybrid networks. In an effort to demonstrate the wider applicability of this concept and to provide a deeper insight into this class of materials, the present work cites additional paradigms of functionalized nanostructures with similar behavior as above. In one case, surface functionalization of anatase nanoparticles (TiO2, an inorganic nanostructure) with a quaternary ammonium organosilane leads to ionically modified nanoparticles that, when electrostatically combined with a poly(ethylene glycol) (PEG)‐tailed sulfonate anion, exhibit liquid‐like behavior in the absence of solvents. In a different but quite interesting case of a bionanostructure, ion‐exchange functionalization of a DNA oligonucleotide with a PEG‐tailed quaternary ammonium cation leads to an easily separable liquid derivative with attractive features. These examples show the versatility of this concept over a range of nanostructures.