The Origin of the Intracellular Silver in Bacteria: A Comprehensive Study using Targeting Gold-Silver Alloy Nanoparticles.

The bactericidal effects of silver nanoparticles (Ag NPs) against infectious strains of multiresistant bacteria is a well-studied phenomenon, highly relevant for many researchers and clinicians battling bacterial infections. However, little is known about the uptake of the Ag NPs into the bacteria, the related uptake mechanisms, and how they are connected to antimicrobial activity. Even less information is available on AgAu alloy NPs uptake.

Nanoscale Three-Dimensional Charge Density and Electric Field Mapping by Electron Holographic Tomography.

The operation of nanoscale electronic devices is related intimately to the three-dimensional (3D) charge density distributions within them. Here, we demonstrate the quantitative 3D mapping of the charge density and long-range electric field associated with an electrically biased carbon fiber nanotip with a spatial resolution of approximately 5 nm using electron holographic tomography in the transmission electron microscope combined with model-based iterative reconstruction. The approach presented here can be applied to a wide range of other nanoscale materials and devices.

Electron-beam-induced charging of an AlO nanotip studied using off-axis electron holography.

Electrostatic charging of specimens during electron, photon or ion irradiation is a complicated and poorly understood phenomenon, which can affect the acquisition and interpretation of experimental data and alter the functional properties of the constituent materials. It is usually linked to secondary electron emission, but also depends on the geometry and electrical properties of the specimen. Here, we use off-axis electron holography in the transmission electron microscope to study electron-beam-induced charging of an insulating AlO nanotip on a conducting support.

transmission electron microscopy of battery cycling: thickness dependent breaking of TiO coating on Si/SiO nanoparticles.

Conformal coating of silicon (Si) anode particles is a common strategy for improving their mechanical integrity, to mitigate battery capacity fading due to particle volume expansion, which can result in particle crumbling due to lithiation induced strain and excessive solid-electrolyte interface formation. Here, we use transmission electron microscopy in an open cell to show that TiO coatings on Si/SiO particles undergo thickness dependent rupture on battery cycling where thicker coatings crumble more readily than thinner (∼5 nm) coatings, which corroborates the difference in their capacities.

Continuous illumination picosecond imaging using a delay line detector in a transmission electron microscope.

Progress towards analysing transitions between steady states demands improvements in time-resolved imaging, both for fundamental research and for applications in information technology. Transmission electron microscopy is a powerful technique for investigating the atomic structure, chemical composition and electromagnetic properties of materials with high spatial resolution and precision. However, the extraction of information about dynamic processes in the ps time regime is often not possible without extensive modification to the instrument while requiring careful control of the operation conditions to not compromise the beam quality.

Quantitative measurement of charge accumulation along a quasi-one-dimensional WO nanowire during electron field emission.

We use an electron holographic method to determine the charge distribution along a quasi-one-dimensional W5O14 nanowire during in situ field emission in a transmission electron microscope. The results show that the continuous charge distribution along the nanowire is not linear, but that there is an additional accumulation of charge at its apex. An analytical expression for this additional contribution to the charge distribution is proposed and its effect on the field enhancement factor and emission current is discussed.

[Forensic and medical significance of the toxic effect of an unidentified substance in the context of chemical trauma].

A statistical analysis of cases of chemical poisonings over a six-year period in Volgograd was conducted. The features and circumstances of 209 fatal poisonings by an unidentified substance were analyzed and systematized. The number of poisoning deaths rose during this period.

Single Electron Precision in the Measurement of Charge Distributions on Electrically Biased Graphene Nanotips Using Electron Holography.

We use off-axis electron holography to measure the electrostatic charge density distributions on graphene-based nanogap devices that have thicknesses of between 1 and 10 monolayers and separations of between 8 and 58 nm with a precision of better than a single unit charge. Our experimental measurements, which are compared with finite element simulations, show that wider graphene tips, which have thicknesses of a single monolayer at their ends, exhibit charge accumulation along their edges. The results are relevant for both fundamental research on graphene electrostatics and applications of graphene nanogaps to single nucleotide detection in DNA sequencing, single molecule electronics, plasmonic antennae, and cold field emission sources.

Tunable Ampere phase plate for low dose imaging of biomolecular complexes.

A novel device that can be used as a tunable support-free phase plate for transmission electron microscopy of weakly scattering specimens is described. The device relies on the generation of a controlled phase shift by the magnetic field of a segment of current-carrying wire that is oriented parallel or antiparallel to the electron beam. The validity of the concept is established using both experimental electron holographic measurements and a theoretical model based on Ampere's law.

Automated discrete electron tomography - Towards routine high-fidelity reconstruction of nanomaterials.

Electron tomography is an essential imaging technique for the investigation of morphology and 3D structure of nanomaterials. This method, however, suffers from well-known missing wedge artifacts due to a restricted tilt range, which limits the objectiveness, repeatability and efficiency of quantitative structural analysis. Discrete tomography represents one of the promising reconstruction techniques for materials science, potentially capable of delivering higher fidelity reconstructions by exploiting the prior knowledge of the limited number of material compositions in a specimen.

Prospects for quantitative and time-resolved double and continuous exposure off-axis electron holography.

The technique of double exposure electron holography, which is based on the superposition of two off-axis electron holograms, was originally introduced before the availability of digital image processing to allow differences between electron-optical phases encoded in two electron holograms to be visualised directly without the need for holographic reconstruction. Here, we review the original method and show how it can now be extended to permit quantitative studies of phase shifts that oscillate in time. We begin with a description of the theory of off-axis electron hologram formation for a time-dependent electron wave that results from the excitation of a specimen using an external stimulus with a square, sinusoidal, triangular or other temporal dependence.

Dense, Regular GaAs Nanowire Arrays by Catalyst-Free Vapor Phase Epitaxy for Light Harvesting.

Density dependent growth and optical properties of periodic arrays of GaAs nanowires (NWs) by fast selective area growth MOVPE are investigated. As the period of the arrays is decreased from 500 nm down to 100 nm, a volume growth enhancement by a factor of up to four compared with the growth of a planar layer is observed. This increase is explained as resulting from increased collection of precursors on the side walls of the nanowires due to the gas flow redistribution in the space between the NWs.

Rapid low dose electron tomography using a direct electron detection camera.

We demonstrate the ability to record a tomographic tilt series containing 3487 images in only 3.5 s by using a direct electron detector in a transmission electron microscope. The electron dose is lower by at least one order of magnitude when compared with that used to record a conventional tilt series of fewer than 100 images in 15-60 minutes and the overall signal-to-noise ratio is greater than 4.

Tunable caustic phenomena in electron wavefields.

Novel caustic phenomena, which contain fold, butterfly and elliptic umbilic catastrophes, are observed in defocused images of two approximately collinear oppositely biased metallic tips in a transmission electron microscope. The observed patterns depend sensitively on defocus, on the applied voltage between the tips and on their separation and lateral offset. Their main features are interpreted on the basis of a projected electrostatic potential model for the electron-optical phase shift.

[Radioecological research of the Irtysh-River's and Ob-River's water, base and flood depositions].

The radioecological research of Irtysh-river and Ob-river was held. The content of 137Cs in Irtysh water was compounded 0.62-1.

[Prospects for designing immunoglobulins to prevent and treat purulent-inflammatory diseases].

The paper gives the results of prophylactic and therapeutic evaluations made in gram-negative opportunistic bacteria-induced pyoinflammatory diseases during retrospective and controlled studies of blood plasma preparations and immunoglobulins that contain antibodies to lipopolysaccharides. The data available in the literature and the authors' own findings confirm the obligatory presence of antibodies to tumor necrosis factor and to other interleukins, as well as the importance of IgM antibodies to various lipopolysaccharide determinants. The paper also presents the results the results of the authors' own investigations to design and evaluate the activity of intravenous immunoglobulin that contains antibodies to IgG and IgM lipopolysaccharides, which is termed panglobulin.

[Anti-Escherichia antibodies in the blood sera from nonimmunized donors and in preparations of human immunoglobulin].

The anti-Escherichia activity of 188 serum samples obtained from nonimmunized blood donors and 157 batches of the preparation of commercial normal human immunoglobulin were evaluated in the passive hemagglutination test with diagnostica containing E. coli antigens (serovars O2, O14, O26) and Kunin antigen, as well as Re-glycolipid Salmonella minnesota strain R595, used as sensitins. The study demonstrated that from sera of nonimmunized blood donors and from normal human immunoglobulin preparations 5-8% of batches containing anti-Escherichia antibodies to E.

[Comparative study of the quality of domestic albumin solution and foreign analogs].

The quality and standards of albumin solutions (5, 10 and 20%) made in this country meet the requirements of national specification documentation. This, however, lacks some standards included into European Pharmacopoeia and mandatory for foreign manufacturers (Na and K ions, hemipigments, polymers, thermostability). The comparative tests of the albumin solutions made in Russia and abroad by conventional European standards showed that Russian solutions by some parameters are inferior to foreign samples.

[The fractional composition of immunoglobulin preparations studied by gel filtration on different carriers and by high-pressure liquid chromatography].

The fractional composition of immunoglobulin preparations produced by different manufacturing enterprises of this country has been studied by gel chromatography in columns packed with different carriers (Sephadex G-200 and ultragel AcA-34) and by high-performance liquid chromatography (HPLC). This study has revealed the nonstandard character of immunoglobulin preparations produced according to the same technological procedure (modified Cohn's method). The fractionation of immunoglobulins on different carriers with the use of different methods has yielded similar results confirmed by the statistical processing of the data.

[Additive effect of repeated impulse air waves on the activity of rat and human hepatic enzymes].

Impulse air waves (IAW) applied in non-destructive and weakly destructive intensities reduced the activity of lysosomal and microsomal enzymes as well as the activity of adenylate cyclase in the liver of laboratory rats. Five times repeated single application of IAW in intensities causing no noticeable biochemical (and morphological) changes led to shifts in the activity of rat hepatic enzymes. IAW which failed to produce a biological effect in humans when applied separately, inhibited noticeably antipyrine biotransformation in volunteers when applied repeatedly 80 times.

[Use of group-specific contaminants A and B in albumin preparations produced from the donor, placental and abortion blood].

Assay of group-specific blood substances (GSBS) A and B was conducted in 21 series of an albumin preparation produced from donors' blood serum, in 11 series of placental and in 5 series of "Postab" albumin. GSBS content was estimated by a comparative use of poly- and monoclonal antibodies prepared in this country. More than 80% of the preparations from donors' blood serum did not contain GSBS A and B.