MINIATURIZATION IN MASS SPECTROMETRY

Expectations for continuous miniaturization in mass spectrometry are not declining for years. Portable instruments are highly welcome by the industry, science, space agencies, forensic laboratories, and many other units. All are striving for the small, cheap, and as good as possible instruments. This review describes the recent developments of miniature mass spectrometers and also provides selected applications where these devices are used. Upcoming perspectives of further development are also discussed. @ 2019 John Wiley & Sons Ltd. Mass Spec Rev     

The sign test and the signed-rank test for interval-valued data

Two versions of the generalized sign test and the signed-rank test for interval-valued data (both for one-sample and paired two-sample problem) are proposed. These two versions correspond to different possible views on the interval outcomes of the experiment—either the epistemic or the ontic one. Each view yields its own approach to data analysis which results in different test construction and the way of carrying on the statistical inference.     

The lifetime prediction of a rotary screw compressor of a liquid cooler subjected to high pressure and high frequency loads

The estimation of the lifetime of high pressure and high frequency loaded components by testing is very costly and time-consuming. The simulation of fatigue life is an important design step in the fast moving and competitive automotive industry, where the steady rise of engineering components and the demand for lightweight construction concurred with enhanced reliability require an optimized dimensioning process. The paper presents the chosen problems of 3D numerical strength and fatigue simulation of a rotary screw compressor of a liquid cooler. The presented results of the FEM mechanical calculation based on a real components. The fatigue analysis were executed using the criterion of critical plane. Local multi-axial state of stresses and deformation has been calculated based on Hooke’s law with simultaneous consideration of kinematics hardening rule of material according to Jiang’s model.     

用于电子政府的数字签名-一种长期的安全结构

The framework of digital signature based on qualified certificates and X.509 architecture is known to have many security risks. Moreover, the fraud prevention mechanism is fragile and does not provide strong guarantees that can be necessary for flow of legal documents. Mediated signatures have been proposed as a mechanism to effectively disable signature cards. In this paper we propose further mechanisms that can be applied on top of mediated RSA, compatible with the standard format, but providing security guarantees even in the case when RSA becomes broken or the keys are compromised. The solution is immune tokleptographic attacks as only deterministic algorithms are used on user's side.     

omega-Hydrazino linear polyethylenimine: a monoconjugation building block for nucleic acid delivery

Nonviral gene therapy requires efficient vectors that are able to deliver nucleic acids inside the targeted cell nucleus. Developing new tools for the synthesis of supramolecular vectors with improved transfection efficiency and better biodistribution is therefore a crucial issue. Here we describe the synthesis of a 140-mer linear polyethylenimine (L-PEI) terminated at one end by a highly nucleophilic hydrazine residue. This cationic polymer, whose backbone is well known for its remarkable gene-delivery efficiency, constitutes a building block for omega-regioselective conjugation to molecules through the formation of stable linkages such as the hydrazone bonds. To demonstrate the potential of the omega-hydrazino linear polyethylenimine, human serum transferrin, a ligand that is well know to improve gene-delivery systems, was used as a model of sensitive material. The blood protein was oxidized to generate an aldehyde function and was subsequently conjugated to hydrazino PEI. The new polyethylenimine-transferrin (PEI-Tf) vector was purified and was shown to condense plasmid DNA into compact superstructures compatible with cellular uptake. Finally, the cellular-binding and gene-delivery properties of PEI/DNA polyplexes incorporating different quantities of transferrin were evaluated by FACS analysis and luciferase assay.     

Precise capture of colors in cultural heritage digitization

A workflow for the color reproduction of digital still images for the purpose of cultural heritage digitization is presented. An analysis was performed to determine the effect of RAW to TIFF transformation; RGB to CIE L*a*b* transformation; white balancing; use of standard color spaces: sRGB, AdobeRGB (1998), ProPhoto RGB, eciRGBv2; custom DCP, and ICC profiles assigning. For the analysis, Color Checker Classic and Digital Color Checker SG targets were used. The precision of the color reproduction was checked against FADGI and Metamorfoze standards. We demonstrate that to obtain high color fidelity reproduction, white balancing and a custom ICC profile are necessary, while DCP profiling could be omitted. © 2016 Wiley Periodicals, Inc. Col Res Appl, 42, 333–336, 2017     

Novel chain structures in group VI elements

Recent developments in high-pressure methods and advances in X-ray crystallography have led to a new level of understanding of phase diagrams and structures of materials under pressure. Recently discovered phenomena such as complex phases of alkali metals, incommensurate host-guest structures, and incommensurately modulated structures have rendered obsolete our conventional wisdom about the range of structures possible in the elements. Using new in situ diffraction techniques, we have resolved the long-standing problem of the phase-transition sequence of sulphur in its non-metallic state. We demonstrate that it is very different from that previously proposed, with only two phases stable between 1.5 GPa and 83 GPa (the pressure of metallization), and temperatures from 300 K to 1,100 K. The phases have a triangular chain and a squared chain structure. The same squared chain structure is found in the heavier group VI element selenium.     

Processing conditions, morphology and properties of a polycarbonate + a thermotropic polymer liquid crystal blend

We have investigated phase structure – properties relationships of polycarbonate (PC) + a polymer liquid crystal (PLC) blends processed in a twin-screw extruder at several conditions. The PLC is PET/0.82 PHB – a copolyester of poly(ethylene terephtalate) and p -hydroxybenzoic acid. For comparison the blend was additionally extruded in a wide range of shear rates in a capillary rheometer at two different spinning rates and compression-molded. The blend processed in the rheometer exhibits lower values of modulus and tensile strength than the blend extruded due to destruction of the initial orientation and dispersion level gained during extrusion. The orientation of PLC-rich islands increases up to the shear rate of 50–100 s^–1, whereas deformation at higher shear rates exhibits a droplet–breakup phenomenon, confirmed by SEM micrographs. The rheological measurements (oscillation mode) evidence a high shear thinning of the PLC. By contrast, the influence of the deformation rate on the viscosity for PC and the blend is negligible, suggesting also a low interaction level in the interfacial area. This conclusion was confirmed by dynamic mechanical measurements. As expected, our experiments prove that structure and properties of the blend are affected by processing (shear and elongation) conditions. Increasing shear rate leads to elongation of dispersed domains but exceeding critical values can lead to droplet breakup and destruction of created structure. The unique morphology created during extrusion can be destroyed during additional processing (in rheometer). Formation of fibrils is also dependent on additional treatment – spinning speed. Optimized spinning speed can lead to 50% increase in stiffness of the blend. Electronic Publication