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At present, deterministic approaches to the hydroerosion processes modeling, which is the informative-physical basis of ultrajet mesodiagnostics (UJM), significantly prevail over other methods of analysis. This contradicts the probabilistic nature of local hydroerosion, which is caused by the formation of an array of eroded particles with highly variable mass-geometric parameters reflecting the realities of the initial microdefects distribution in the surface layer of the analyzed object (OA). Therefore, probabilistic modeling is a physically more reasonable tool for describing multi-factor processes in the ultrajet interactions zone, including the peculiarities of ultrajet hydroerosion. Hence, this paper proposes a probabilistic approach to modeling the process of hydroerosion damage, based on the separation of the particle from the material surface as a result of the interaction of necessary and sufficient conditions for dispersion. The obtained calculation data (probabilistic analysis) are close to the results of live experiments, which, in turn, allows recommending this approach of mathematical formalization of the minimally invasive quality control method using complicated configuration parts surface properties ultrajet mesodiagnostics, and also OA produced from anisotropic materials, widely used in aviation, rocket, and space technology.

Hair is used as a biomarker of manganese (Mn) exposure, yet there is limited evidence to support its utility to quantify internal vs external Mn exposure. C57BL/6 J mice and Sprague-Dawley rats were exposed in two blocks of 3 subcutaneous injections every 3 days starting on day 0 or 20. The control group received two blocks of saline (vehicle); Treatment A received the first block as Mn (50 mg/kg MnCl2 tetrahydrate), with the second block as either methylmercury (MeHg at 2.6 or 1.3 mg/kg) for mice or vehicle for rats; and Treatment B received Mn for both blocks. Hair was collected on days 0 and 60 from all treatment groups and Mn quantified by inductively coupled plasma-mass spectrometry (ICP-MS) and total Hg by Direct Mercury Analyzer (DMA). No correlation between internal Mn dose and hair Mn was observed, whereas hair Hg was significantly elevated in MeHg exposed vs non-exposed mice. Whole body Mn content at day 60 was quantified postmortem by neutron activation analysis, which detected significantly elevated Mn for Treatment B in mice and rats. Overall, we find no evidence to support the use of hair as a valid biomarker for internal exposure to Mn at a neurotoxic level.

Potassium is known for its effect on modifiable chronic diseases like hypertension, cardiac disease, diabetes (type-2), and bone health. In this study, a new method, neutron generator based neutron activation analysis (NAA), was utilized to measure potassium (K) in mouse carcasses. A DD110 neutron generator based NAA assembly was used for irradiation.Thirty-two postmortem mice (n= 16 males and 16 females, average weight $$22.02\pm 1.3$$ 22.02 ± 1.3 and $$17.9\pm 1.1$$ 17.9 ± 1.1 g) were employed for this study. Soft-tissue equivalent mouse phantoms were prepared for the calibration. All mice were irradiated for 10 minutes, and the gamma spectrum with 42K was collected using a high efficiency, high purity germanium (HPGe) detector. A lead shielding assembly was designed and developed around the HPGe detector to obtain an improved detection limit. Each mouse sample was irradiated and measured twice to reduce uncertainty. The average potassium concentration was found to be significantly higher in males $$(2846 \pm 525 \upmu g/g)$$ ( 2846 ± 525 μ g / g ) compared to females $$(2116.2 \pm 432 \upmu g/g)$$ ( 2116.2 ± 432 μ g / g ) . We also observed a significant correlation between potassium concentration and the weight of the mice. The detection limit for potassium quantification with the NAA system was 46 ppm. The radiation dose to the mouse was approximately 56 $${ \pm 1.6 }$$ ± 1.6 mSv for 10-min irradiation. In conclusion, this method is suitable for estimating individual potassium concentration in small animals. The direct evaluation of total body potassium in small animals provides a new way to estimate potassium uptake in animal models. This method can be adapted later to quantify potassium in the human hand and small animals in vivo. When used in vivo, it is also expected to be a valuable tool for longitudinal assessment, kinetics, and health outcomes.

Available assays for measuring cellular manganese (Mn) levels require cell lysis, restricting longitudinal experiments and multiplexed outcome measures. Conducting a screen of small molecules known to alter cellular Mn levels, we report here that one of these chemicals induces rapid Mn efflux. We describe this activity and the development and implementation of an assay centered on this small molecule, named manganese-extracting small molecule (MESM). Using inductively-coupled plasma–MS, we validated that this assay, termed here "manganese-extracting small molecule estimation route" (MESMER), can accurately assess Mn in mammalian cells. Furthermore, we found evidence that MESM acts as a Mn-selective ionophore, and we observed that it has increased rates of Mn membrane transport, reduced cytotoxicity, and increased selectivity for Mn over calcium compared with two established Mn ionophores, calcimycin (A23187) and ionomycin. Finally, we applied MESMER to test whether prior Mn exposures subsequently affect cellular Mn levels. We found that cells receiving continuous, elevated extracellular Mn accumulate less Mn than cells receiving equally-elevated Mn for the first time for 24 h, indicating a compensatory cellular homeostatic response. Use of the MESMER assay versus a comparable detergent lysis-based assay, cellular Fura-2 Mn extraction assay, reduced the number of cells and materials required for performing a similar but cell lethality-based experiment to 25% of the normally required sample size. We conclude that MESMER can accurately quantify cellular Mn levels in two independent cells lines through an ionophore-based mechanism, maintaining cell viability and enabling longitudinal assessment within the same cultures.

In this article, a description is given of the methods of extending service life of parts whose surface comes in contact with a polymer in the process of its conversion into articles. The system of lubrication of press molds for injection molding of plastic (molding plastic under pressure), including devices for blast cleaning and lubrication of press molds is described.

The antifrictional properties and wear resistance of polymeric materials when sliding on metal surface are studied. The factors contributing to enhancement of the reliability and life of plastic sliding bearings and mobile seals are determined.

A simplified procedure is examined for preliminary estimation of the tightening moment of threaded pipe connections with a conical thread, and the location of contact stresses in the thread fillets. An example is given for the analysis of threaded joints in pump-compressor piles (D = 60 mm, titanium VT1-0), which are sunk in drilled wells.

Surface treatment of titanium joint components so as to prevent jamming and increase their wear resistance is considered. Threaded joints in titanium pipes with a modified surface undergo bench tests.

The method developed makes it possible to simplify assembly of fiberglass pipes and to increase their strength and tightness in the joint zone. A simplified method is provided for calculating metal coupling and fiberglass pipe characteristics.

Surface hardening methods are considered and analyzed for titanium and titanium alloy components, including engineering solutions for writing inventions.

A device is considered for cutting a conical thread of a conical rack using a conical leader, distinguished by structural simplicity and improved cut thread accuracy. This is achieved by forced locking of all device components.

In this article, a description is given of a simple, reliable, and durable device for machining (finishing) tapered surface. Enhancement of reliability and durability of the device as well as improvement in the quality of the finished surface can be achieved by distributing the load transmitted to the force-locking elements and reducing the vibration of the device.

A device is considered for depositing a lubricant under pressure on a threaded surface, which includes a lubrication head joined by a pipe to a vessel containing the lubricant. In the lower part of the lubrication head, there is an element composed of elastic material reproducing the profile of the lubricated surface. The device allows one to operate automatically in a stable fashion to apply lubricant of optimum thickness, including directly after cutting the thread.

Isopenicillin N synthase is a key enzyme in the biosynthesis of penicillin and cephalosporin antibiotics, catalyzing the oxidative ring closure of delta-(L-alpha-aminoadipoyl)-L-cysteinyl-D-valine to form isopenicillin N. Recent advances in our understanding of the unique chemistry of this enzyme have come through the combined application of spectroscopic, molecular genetic and crystallographic approaches and led to important new insights into the structure and function of this enzyme. Here we review new information on the nature of the endogenous ligands that constitute the ferrous iron active site, sequence evidence for a novel structural motif involved in iron binding in this and related non-heme iron dependent dioxygenases, crystal structure studies on the enzyme and its substrate complex and the impact of these and site-directed mutagenesis studies for unraveling the mechanism of the isopenicillin N synthase reaction.

Triboelectric phenomena have been used to process sealing materials for fixed demountable joints in pipelines (threaded, flanged, and so on) in order to improve the sealing.

The design of a device for the preparation of liquid (preferentially ecologically harmful) mixtures is indicated; the mixing process, introduction of liquids to be mixed, and discharge of the mixture take place in a closed chamber.

This paper contains a discussion of how two job task/human performance analysis systems have been used in the nuclear utility industry to a) determine training program curriculum and content requirements, and b) provide data for management decisions regarding training system development. This is a presentation of the methods used in a performance analysis of a variety of workers, the products created, and to what end those products were used. The paper is a pragmatic application which training systems personnel can use in their work situations to develop training programs grounded in data generated by job task/human performance analysis.

Rhesus monkeys were trained to press panels to escape or avoid shock. Escape and avoidance training were combined factorially with feature-positive (FP) and feature-negative (FN) discriminations. In the FP situation, S+ trials were characterized by one red and two green panel displays and S− consisted of an all green panel array. In the FN arrangement, S+ and S− arrays were reversed. When compared properly, FP discriminations were learned more readily than FN discriminations in both escape and avoidance training conditions. Positive tracking was associated with FP discriminations, and feature avoidance characterized the FN tasks. These data suggest that in primates, feature responses (i.e., tracking behaviors) are more a function of the operant contingency than of the Pavlovian correlation.

1. Chemicothermal treatment of VT6 alloy in a melt consisting of 45% cadmium iodide and 55% potassium iodide makes it possible to use this alloy for highly loaded threaded joints operating with repeated screwing together and a specific tightening load up to 60 MPa. 2. Use of annealed alloy VT6 in highly loaded hermetically sealed threaded joints is not recommended.

1. Changes in the crystal structure leading to an increase of hardness occur in the surface layers of steel KhVG under the influence of dynamic and static interactions with polyethylene. 2. The heat treatment of forming equipment used in manufacturing polyethylene parts should not produce the maximum hardness, since it leads to premature embrittlement and failure of the working surfaces. 3. To obtain forming equipment with a long service life it is necessary to create a permanent barrier to prevent contact of polyethylene with the surface of the metal.