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In modern biomedical science and developmental biology, there is significant interest in optical tagging to study individual cell behavior and migration in large cellular populations. However, there is currently no tagging system that can be used for labeling individual cells on demand in situwith subsequent discrimination in between and long-term tracking of individual cells. In this article, we demonstrate such a system based on photoconversion of the fluorescent dye rhodamine B co-confined with carbon nanodots in the volume of micron-sized polyelectrolyte capsules. We show that this new fluorescent convertible capsule coding system is robust and is actively uptaken by cell lines while demonstrating low toxicity. Using a variety of cellular lines, we demonstrate how this tagging system can be used for code-like marking and long-term tracking of multiple individual cells in large cellular populations.

The article presents the results of numerical and experimental studies of stress-strain curves of 1D-reinforced polymer composite materials based on hollow porous fibers and epoxy matrix. The two-scale nature of the composite under research was taken into account. A surrogate easily parameterized model based on Bezier curves was developed and used to approximate the stress-strain curve of ductile material. The calculations were performed using reversible homogenization and finite element methods, which were implemented in computational subsystem of DCS GCD. Representative volume elements of the investigated materials were created using the geometry generating subsystem of DCS GCD. Test samples were made using three-axis milling machine and compression tests were carried out. Computational results of effective stress-strain curves determination were obtained and compared with experiments.

The possible structures of (CdSe)nand (CdS)n(nup to 34) nanoclusters were systematically studied using the ab initio random structure searching (AIRSS) method. We have been able to find stable, symmetric nanoclusters not previously discovered; using the computed pair distribution functions, we have put forward a hypothesis for the increased stability of these clusters. We have also been able to investigate structural features of the transformation to the bulk: for (CdS)nwith n< 16 and (CdSe)nwith n< 21, structures based on rings and cages with coordination number up to 3 are favored, while for larger n, the minimum-energy structures are more bulklike with an average coordination number larger than 3. This indicates a gradual transformation from a cagelike structure to a bulklike structure as the number of atoms increases. One striking finding was that for any value of n, the range of structures formed a continuous distribution of cluster energies rather than there being significant energy differences between them. This work created an extensive database of benchmarks and candidate structures for these systems.

During this work, a program complex containing specialized libraries, desktop applications and web services is developed for the purposes of Earth remote sensing and managing space shooting orders lifecycle. Complex allows operators and remote clients a functionality to create order for getting Earth images in different modes w.r.t. target satellite ballistic data and shooting technological processes. As a part of complex, libraries to form optimal (in prescribed sense) shooting programs, including flight tasks generation. Software architecture allows users to add new tasks, new shooting modes, new satellites and terrain segment items for perpective earth remote sensing orbital constellations.

We report a direct photoelectrochemical response from low cost carbon dots (CDs) prepared from chitosan viaa solvothermal method. The carbon dots were covalently linked to an indium tin oxide (ITO) surface through a self-assembled silane monolayer. We attribute the photocurrent of the ITO–silane–CD surface to a photogenerated electron-transfer process by CDs under illumination with a wavelength of 420 nm to 450 nm. The self-assembled monolayer of CDs was used for ac-photocurrent imaging of the surface with micron scale lateral resolution. This discovery opens up new applications for CDs as biocompatible, light-addressable electrochemical sensors in bioanalytical and bioimaging applications.

Luminescent carbon nanoparticles represent a new class of photoluminescent nanomaterials. Growing interest in these nanoparticles stems from straightforward methods of their synthesis, a wide variety of available precursors, the lack of toxicity, photo stability and simple surface modification for further application. Due to low cytotoxicity and tunable optical properties of carbon nanoparticles, they are used in various fields of biology and medicine. At the same time, current application of carbon nanoparticles is limited by the lack of understanding of the fundamental relationship between their structure and properties. The review focuses on the latest trends in the synthesis, study of the structure, composition and properties of carbon nanoparticles and on their biomedical applications.The bibliography includes 112 references.

Designing and fabricating multifunctional nanocomposite microcapsules are considerable interests in both academic and industrial research aspects. This work first reports an innovative approach to in situsynthesize and assemble fluorescent carbon dots (CDs) into polyelectrolyte microcapsules, obtaining highly biocompatible nanocomposite microcapsules with excellent luminescence that facilitate imaging and identification in vitro, yet with the feasibility to load small molecules and ultrasound responsiveness to trigger their release. CDs are produced in situin (PAH/PSS)4microcapsule shells by carbonization of dextran molecules under relatively mild hydrothermal treatment. Compared with the collapsed and film-like (PAH/PSS)4microcapsules, the novel composite microcapsules show a free-standing structure, smaller size, and thicker shell. CDs are proven to be fabricated and embedded in PAH/PSS multilayers, and the formed PAH/PSS/CD microcapsules are endowed with strong luminescence, as verified by the transmission electron microscopy, fluorescence spectra, and confocal laser scanning microscopy results. The in situformation of CDs in capsule shells also empowers these capsules with ultrasound responsiveness and reduced permeability. The feasibility of encapsulation of small molecules (rhodamine B) and ultrasound-triggered release is also shown. Most importantly, due to the intrinsic biocompatible property and photostability of CDs, these fluorescent PAH/PSS/CD microcapsules show negligible cell toxicity and low photobleaching, which are impossible for capsules composited with conventional organic dyes and semiconductor quantum dots.

The study of the G-mode pressure coefficients of carbon nanotubes, reflecting the stiff sp2bond pressure dependence, is essential to the understanding of their extraordinary mechanical properties as well as fundamental mechanics. However, it is hindered by the availability of carbon nanotubes samples only as bundles or isolated with surfactants. Octadecylamine-functionalized carbon nanotubes are mostly of a single diameter and can be stably dispersed in 1,2-dichloroethane and chloroform without surfactants. Here we perform high-pressure Raman spectroscopy on these tubes and obtain their experimental G-mode pressure coefficients for individual tubes and bundles. The G+pressure coefficient for bundles is only about half of that for individual tubes in 1,2-dichloroethane and is about two-thirds in chloroform. The G–pressure coefficient for bundles is about one-third of G+in 1,2-dichloroethane and about the same in chloroform. These results for the first time provide unambiguous experimental evidence of the significant effect of bundling on carbon nanotubes’ G-mode pressure coefficients, identifying it as one of the major reasons for the lack of consensus on what the values should be in the literature.

Single‐wall carbon nanotubes modified by anionic polyelectrolyte molecules are embedded into the shells of microcapsules. Carbon nanotubes serve as rigid rods in a softer polymeric capsule, which forms a free‐standing shell upon treatment with glutaraldehyde and subsequent drying. The embedded carbon nanotubes exhibit a broad absorption in the UV–near‐infrared part of the spectrum, and that allows point‐wise activation and opening of the microcapsules by laser. Raman signal analysis shows changes of carbon‐nanotube‐specific lines after high‐power laser irradiation, which is characteristic of the formation of disordered carbonlike structures. These polyelectrolyte/carbon nanotube composite capsules represent a novel light‐addressable type of microcontainers.

Due to the emerging role of protein kinase CK2 as a molecule that participates not only in the development of some cancers but also in viral infections and inflammatory failures, small organic inhibitors of CK2, besides application in scientific research, may have therapeutic significance. In this paper, we present a new class of CK2 inhibitors3-carboxy-4(1H)-quinolones. This class of inhibitors has been selected via receptor-based virtual screening of the Otava compound library. It was revealed that the most active compounds, 5,6,8-trichloro-4-oxo-1,4-dihydroquinoline-3-carboxylic acid (7) (IC50 0.3 M) and 4-oxo-1,4-dihydrobenzohquinoline-3-carboxylic acid (9) (IC50 1 M), are ATP competitive (Kivalues are 0.06 and 0.28 M, respectively). Evaluation of the inhibitors on seven protein kinases shows considerable selectivity toward CK2. According to theoretical calculations and experimental data, a structural model describing the key features of 3-carboxy-4(1H)-quinolones responsible for tight binding to CK2 active site has been developed.

Abstract With a view to creating Si LEDs, the structural and luminescent properties of SiOxNy films containing Si nanocrystals in the SiOxNy matrix are studied experimentally. It is found that the film structure (nanocrystal size and concentration, the presence of an amorphous phase, etc.) and the spectrum and intensity of photoluminescence (PL) and electroluminescence (EL) are strongly dependent on the Si stoichiometric excess δ and annealing conditions. At δ≈ 10%, unannealed films are amorphous and contain Si clusters of size < 2 nm, as deduced from the TEM and microdiffraction data obtained. Annealing at 800–1000°C for 10–60 min produces Si crystals 3–5 nm in size with a concentration of ≈1018 cm−3. The annealed films exhibit room-temperature PL and EL over the wavelength range 400–850 nm with intensity peaks located at 50–60 and 60–70 nm, respectively. The PL and EL spectra are found to be qualitatively similar. This suggests that both the PL and the EL should be associated with the formation of luminescent centers at nanocrystal–matrix interfaces and in boundary regions. However, the two phenomena should differ in the mechanism by which the centers are excited. With the EL, excitation should occur by impact processes due to carrier heating in high electric fields. It is found that as δ increases, so does the proportion of large amorphous Si clusters with a high density of dangling bonds. This enhances nonradiative recombination and suppresses luminescence.

Low-density zeolites collapse to the rigid amorphous state at temperatures that are well below the melting points of crystals of the same composition but of conventional density. Here we show, by using a range of experimental techniques, how the phenomenon of amorphization is time dependent, and how the dynamics of order–disorder transitions in zeolites under temperature and pressure are equivalent. As a result, thermobaric regions of instability can be charted, which are indicative of polyamorphism. Moreover, the boundaries of these zones depend on the rate at which temperature or pressure is ramped. By directly comparing the rheology of collapse with structural relaxation in equivalent melts, we conclude that zeolites amorphize like very strong liquids and, if compression occurs slowly, this is likely to lead to the synthesis of perfect glasses.

We prove a theorem that describes P-faithful partially ordered sets.

Although potentially extremely important for understanding the high-pressure microscopic behaviour of materials, over the years the area of high-pressure EXAFS in particular using diamond anvil cells has proved to be technically difficult. This has significantly hampered its development. The interference of X-ray dimaction from the diamonds in the diamond anvil cell with the absorption signal has proved to be a challenging problem to tackle, restricting the use of high-pressure EXAFS to energies below about 11 key Below 11 keV however the technique is also limited due to absorption of incident X-rays by the diamonds making it virtually impossible to conduct X-ray absorption experiments below about 9keV In this paper we describe in detail the methodology for scanriirig high-pressure EXAFS in diamond anvil cells and examine the origins of the associated problems and ways of dealing with them. We also demonstrate that it is possible to extend the useful range of studied absorption edges from 7keV up to at least 30keV This brings about new opportunities for high pressure EXAFS using diamond anvil cells.

Both angle-dispersive and EXAFS experiments have been carried out to investigate the structural ordering of the high-pressure (hp) and high-pressure high-temperature (hp/ht) phases of GaSb. The diffraction patterns of all the different phases of GaSb have shown an absence of long-range order, while the EXAFS studies have demonstrated the lack of complete short-range order. GaSb is the only semiconductor compound among the III–V and II–VI systems to present such behaviour in all of its different hp and hp/ht phases.

A new facility for simultaneous extended X‐ray absorption of fine structure (EXAFS), X‐ray diffraction and photoluminescence measurements under high pressures has been developed for use on station 9.3 at the Daresbury Laboratory Synchrotron Radiation Source. This high‐pressure facility can be used at any suitable beamline at a synchrotron source. Full remote operation of the rig allows simultaneous collection of optical and structural data while varying the pressure. The set‐up is very flexible and can be tailored for a particular experiment, such as time‐ or temperature‐dependent measurements. A new approach to the collection of high‐pressure EXAFS data is also presented. The approach significantly shortens the experimental times and allows a dramatic increase in the quality of EXAFS data collected. It also opens up the possibility for EXAFS data collection at any pressure which can be generated using a diamond cell. The high quality of data collected is demonstrated with a GaN case study. Particular attention will be paid to the use of energy‐dispersive EXAFS and quick‐scanning EXAFS techniques under pressure.

A unified algorithm is proposed for the solution of conjugate problems of heat exchange in one-sided and two-sided heating of solid bodies in concurrent flow and counterflow.

The peculiarities of the semiconductor-to-metal transition in the case of tetrahedral-bonded amorphous semiconductor a-GaSb were investigated. The bulk disordered samples of gallium antimonide were obtained by solid state amorphization from high pressure phase. The metallization occurs at P∼3. 5-4 GPa and is accompanied by volume anomaly. Bulk modulus of amorphous semiconducting phase is less than that of crystalline modification. The transition to metallic state is interpreted by the gradual changes of amorphous network topology, which lead to significant structural reconstruction to more close packed phase at metallization pressure.

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We have prepared Cu nanodot (ND) films as substrates for surface-enhanced Raman scattering (SERS) study of trace amount molecules. The ND films were processed via electrodeposition using porous alumina templates. The test sample rhodamine 6G (R6G) yielded the well-known R6G Raman spectrum with much lower background intensity when measured on these samples (for a concentration of 10−4 M). Furthermore, after deposition of a thin film of Au or Ag on Cu-NDs the SERS signal increased up to 3 orders of magnitude. The spectra probed from different locations of a sample are almost identical and the template parameters are controllable. The present method, therefore, offers significant potential in use of such ND-films for future SERS studies.A novel, template-synthesized SERS-active substrate. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Luminescent carbon nanoparticles represent a new class of photoluminescent nanomaterials. Growing interest in these nanoparticles stems from straightforward methods of their synthesis, a wide variety of available precursors, the lack of toxicity, photo stability and simple surface modification for further application. Due to low cytotoxicity and tunable optical properties of carbon nanoparticles, they are used in various fields of biology and medicine. At the same time, current application of carbon nanoparticles is limited by the lack of understanding of the fundamental relationship between their structure and properties. The review focuses on the latest trends in the synthesis, study of the structure, composition and properties of carbon nanoparticles and on their biomedical applications.