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Modular nanotransporters (MNTs) are multifunctional chimeric polypeptides for the multistep transport of locally acting cytotoxic agents into the nuclei of cancer target cells. MNTs consist of several polypeptide domains (functional modules) for the recognition of a cell‐surface internalizable receptor, pH‐dependent endosomal escape and subsequent transport into the nucleus through the nuclear pores. MNTs are a promising means for cancer treatment. As has been shown previously, all of the modules of MNTs retain their functionalities. Despite their importance, there is no structural information available about these chimeric polypeptides, which hampers the creation of new MNT variants. Here, a low‐resolution 3D structure of an MNT is presented which was obtained by atomic force microscopy, transmission electron microscopy and small‐angle X‐ray scattering coupled to size‐exclusion chromatography. The data suggest that the MNT can adopt two main conformations, but in both conformations the protein N‐ and C‐termini are distanced and do not influence each other. The change in the MNT conformation during acidification of the medium was also studied. It was shown that the fraction of the elongated conformation increases upon acidification. The results of this work will be useful for the development of MNTs that are suitable for clinical trials and possible therapeutic applications. [ABSTRACT FROM AUTHOR]

Under severe or prolonged stress, bacteria produce a nonspecific DNA‐binding protein (Dps), which effectively protects DNA against damaging agents both in vitro and in vivo by forming intracellular biocrystals. The phenomenon of protective crystallization of DNA in living cells has been intensively investigated during the last two decades; however, the results of studies are somewhat contradictory, and up to now, there has been no direct determination of a Dps–DNA crystal structure. Here, we report the in vitro analysis of the vital process of Dps–DNA co‐crystallization using two complementary structural methods: synchrotron small‐angle X‐ray scattering in solution and cryo‐electron tomography. Importantly, for the first time, the DNA in the co‐crystals was visualized, and the lattice parameters of the crystalline Dps–DNA complex were determined. [ABSTRACT FROM AUTHOR]

Field electron emission from thin films composed of solely metallic or semiconducting single‐walled carbon nanotubes is investigated using a scanning tip anode technique. Metallic and semiconducting nanotubes are separated by aqueous two‐phase extraction. Local field emission centers observed on nanotube films of both types showed non‐linear Fowler–Nordheim (FN) plots bent downwards. The curving of FN plots is much stronger for semiconducting nanotubes which is explained by their higher electrical resistance and stronger field penetration effect compared to metallic nanotubes. Particular nanotubes of both types revealed oscillations in current–voltage characteristics. The periodic oscillations indicated that the field emission current is modulated either by resonant tunnelling from confinement states in nano‐objects formed by adsorbates or by the Coulomb blockade effect that can occur for emission from short carbon nanotubes. [ABSTRACT FROM AUTHOR]

Luminescent properties of needle‐like single crystal diamonds are investigated in a wide range of wavelength. The luminescent spectra with zero phonon lines centered at 389, 442, 468, 534, 563, 575, and 738 nm are detected using excitation by photons and electrons. Obtained photo‐ and cathodo‐luminescent (PL and CL) spectra indicate presence in the single‐crystal diamond needles of nitrogen‐ and silicon‐vacancy centers as well as substitutional or/and interstitials related to these atomic impurities. The dependencies of PL intensities of the 575 and 738 nm lines (related, correspondingly, to nitrogen‐ and silicon‐vacancy centers) on excitation wavelength are determined. Time‐resolved measurements are performed for the 575 nm PL line. The luminescence decay behavior for this line demonstrates the presence of recombination processes with characteristic times of about 28 ns (on 200 ns time scale) and 2.8 ns (on 20 ns time scale). [ABSTRACT FROM AUTHOR]

This paper reports the analysis of the intensity of diamond line in the Raman spectra of laser modified layers with different thickness on a diamond surface. Since the diamond line passing from substrate through the absorbing layer of moderate thickness can be registered, the thickness of local area is estimated from its micro‐Raman spectra. The comparison between Raman scattering and direct observation of the graphitized layer by transmission electron microscopy shows that Raman spectroscopy can be used as an alternative non‐destructive method for measuring a moderate thickness of graphitized layers. [ABSTRACT FROM AUTHOR]

The synthesis of graphene on thin copper film deposited on quartz substrate is reported. The copper films are fabricated with different thickness of 300 and 1150 nm and then crystallized during thermal annealing that occurs at temperature of 950 and 1000 °C for 30 or 90 min. The size of copper grains increases with increasing of the temperature and the time of annealing that results in increasing of graphene film size. The deposited copper films are studied by electron backscatter diffraction and synthesized graphene films are analyzed by Raman spectroscopy and scanning probe microscopy. Proposed phase contrast mode of the scanning probe microscopy demonstrates high lateral resolution and sensitivity to the presence of graphene with different number of layers. It is found that graphene monolayer is preferably formed on the surface of copper grains with orientation {111} and proposed techniques can be used for the analysis of the evolution of graphene growth. [ABSTRACT FROM AUTHOR]

The field electron emission characteristics of individual tips of a silicon field emitter array are analyzed. The array of conical‐shaped tips is fabricated on a p‐type silicon wafer by using reactive ion etching and sharpening oxidation. The tips are decorated with single tungsten nanoparticles at their apexes. Furthermore, the focused ion beam is also used to increase surface conductivity of some of the tips. Comparative measurements of field emission are performed by using the scanning anode probe field emission microscopy technique. All types of tips demonstrated emission activation consisting of a sudden current increase at a certain value of the applied voltage. Compared to the pristine tips, a noticeable reduction of the saturation effect in the current–voltage characteristics and a smaller light sensitivity for the decorated tips is found. For ion‐treated tips, saturation effects and light sensitivity are completely suppressed. Scanning electron microscopy observations reveal the formation of single nanoscale protrusions extending from the metal particles and from the apexes of bare ion‐treated tips after exposure under strong electric fields during the field emission measurements. The influence of protrusions growth on characteristics of silicon field emitter arrays is discussed. [ABSTRACT FROM AUTHOR]