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In recent years several electrical wound management systems, so called electroceuticals, have been introduced claiming an induced electrical response in the wounded tissue. Some have external current and voltage sources while others have internal constructions aiming at creating necessary therapeutic currents. We investigate two representative electroceuticals by mapping out their electrical field landscapes using a previously developed skin model within a numerical simulation scheme. We find very strong fields from the electroceuticals of the order of 1 kV/m amenable for electrotaxic influence on pertinent cell types for wound healing. Current densities can locally be as high as 1 A/cm2.

The presented results describe the effect of severe plastic deformation on the structure and mechanical properties of AA5083 and AA5754 alloys. Both materials were subjected to single hydrostatic extrusion (HE) and cumulative hydrostatic extrusion in the case of AA5083 and a combination of plastic deformation by equal-channel angular pressing (ECAP) with the next HE for AA5754. After the deformation, both alloys featured a homogeneous and finely divided microstructure with average grain size deq = 140 nm and 125 nm for AA5083 and AA5754, respectively. The selection of plastic forming parameters enabled a significant increase in the UTS tensile strength and YS yield stress in both alloys - UTS = 510 MPa and YS = 500 MPa for alloy AA5083 after cumulative HE, and 450 MPa and 440 MPa for alloy AA5754 after the combination of ECAP and HE, respectively. It has been shown on the example of AA5083 alloy that after the deformation the threads of the fasteners made of this material are more accurate and workable at lower cutting speeds, which saves the cutting tools. The resultant properties of AA5083 and AA5754 alloys match the minimum requirements for the strongest Al-Zn alloys of the 7xxx series, which, however, due to the considerably lower corrosion resistance, can be replaced in many responsible structures by the AA5xxx series Al-Mg alloys presented in this paper. [ABSTRACT FROM AUTHOR]

The broad range applications of Ultra-Fine Grained metals is substantially limited by the lack of a welding method that allows them to be joined without losing the strong refinement of structure. From this point of view, the solid state welding processes are privileged. Friction welding tests were carried out on UFG 316L stainless steel. A joining process at high temperature activates the recrystallization, therefore the friction welding parameters were selected according to the criterion of the lowest degree of weakness due to recrystallization in the heat affected zone. In order to characterize the structure of basic material and selected areas of the obtained joint, were performed SEM, TEM and metallographic examinations in terms of hardness and range of softening of the material and tensile test. Despite the short time and relatively low welding temperature, results of the test by scanning electron microscopy and transmission electron microscopy confirmed the loss of the primary ultrafine structure in the Heat Affected Zone of welded joint. [ABSTRACT FROM AUTHOR]

The study attempts to investigate the influence of severe plastic deformation (SPD in the hydrostatic extrusion (HE) process on the anisotropy of the structure and mechanical properties of the AA 6060 alloy. Material in isotropic condition was subjected to a single round of hydrostatic extrusion with three different degrees of deformation ( ε = 1.23, 1.57, 2.28). They allowed the grain size to be fragmented to the nanocrystalline level. Mechanical properties of the AA 6060 alloy, examined on mini-samples, showed an increase in ultimate tensile strength (UTS) and yield strength (YS) as compared to the initial material. Significant strengthening of the material results from high grain refinement in transverse section, from »220 μm in the initial material to »300 nm following the HE process. The material was characterized by the occurrence of structure anisotropy, which may determine the potential use of the material. Static tensile tests of mini-samples showed »10% anisotropy of properties between longitudinal and transverse cross-sections. In the AA6060 alloy, impact anisotropy was found depending on the direction of its testing. Higher impact toughness was observed in the cross-section parallel to the HE direction. The results obtained allow to analyze the characteristic structure created during the HE process and result in more efficient use of the AA 6060 alloy in applications. [ABSTRACT FROM AUTHOR]

Objective: Wound healing is enhanced in the presence of an external electrical field. The purpose of this study was first to investigate whether microelectric potentials (EPs) can be generated when the innovative design of a silver (Ag)- and zinc (Zn)-printed wound care device was exposed to saline solution which is commonly used to clean wound sites; and second to measure the generated EPs while the device was exposed to bacterial culture suspensions to mimic infection. Method: An Ag/Zn-printed test specimen as a wound care device was designed to accommodate Ag and Zn half-cell potentials by alternatively printing them on a woven polyester material in a well-characterised dot matrix pattern. A well-calibrated high impedance EPs measuring system was used to measure any EPs generated. Ultrasensitive inductively coupled plasma analysis was performed to determine whether the device induced any increase in trace metals in rabbit blood following implantation for 2–4 weeks. Results: EPs were consistently generated under various conductive solutions at the levels of 120.4±26.3mV (average±standard deviation) on Ag dots and -506.5±76.3mV over Zn dots to form microcircuits with EPs of 626.7±86.3mV between the Ag and Zn metallic elements of the dressing. Interestingly, the patterns of EPs generated with stable polarities were consistent when the device was exposed to bacterial suspensions for mimicking wound infection. Implantation of the device did not cause any increase in Ag or Zn in rabbit blood. Conclusion: The Ag/Zn-printed wound device generated sustained EPs successfully in the presence of various conductive fluids without changing EPs including polarities. Consistently generated EPs at each battery couple with Ag/Zn-based wound device would restore disrupted physiologic bioelectric signals on wound sites, which could lead to improved wound healing. [ABSTRACT FROM AUTHOR]

The development of bioabsorbable implants from Zn alloys is one of the main interests in the new generation of biomaterials. The main drawbacks of Zn-based materials are their insufficient mechanical properties. In the presented studies, a quaternary alloy composed of zinc with magnesium (0.2-1 wt. %), calcium (0.1-0.5 wt. %) and strontium (0.05-0.5 wt. %) was prepared by gravity casting followed by hot extrusion and then by hydrostatic extrusion. Microstructural characterization using scanning electron microscopy (SEM) and X-ray diffraction (XRD) phase analysis was performed. The mechanical properties were examined, using static tensile tests. Corrosion properties were analyzed using immersion tests. Samples were immersed in Hanks' solution (temperature = 37 °C, pH = 7.4) for 14 days. All alloys were subjected after corrosion to SEM observations on the surface and cross-section. The corrosion rate was also calculated. The microstructure of the investigated quaternary alloy consists of the α-Zn grains and intermetallic phases Mg2Zn11, CaZn13 and SrZn13 with different grain sizes and distribution, which impacted both mechanical and corrosion properties. Thanks to the alloying by the addition of Mg, Ca, and Sr and plastic deformation using hydrostatic extrusion, outstanding mechanical properties were obtained along with improvement in uniformity of corrosion rate.

Dental implantology is one of the most dynamically developing fields of dentistry, which, despite developing clinical knowledge and new technologies, is still associated with many complications that may lead to the loss of the implant or the development of the disease, including peri-implantitis. One of the reasons for this condition may be the fact that dental implants cannot yield a proper osseointegration process due to the development of oral microbiota dysbiosis and the accompanying inflammation caused by immunological imbalance. This study aims to present current knowledge as to the impact of oral microflora dysbiosis and deregulation of the immune system on the course of failures observed in dental implantology. Evidence points to a strong correlation between these biological disturbances and implant complications, often stemming from improper osseointegration, pathogenic biofilms on implants, as well as an exacerbated inflammatory response. Technological enhancements in implant design may mitigate pathogen colonization and inflammation, underscoring implant success rates.

The research presented in this paper focused on optimising the process of unconventional plastic forming by hydrostatic extrusion (HE) with post-processing heat treatment of a copper alloy (CuCrZr) for electro-discharge machining (EDM) applications. The treatment was carried out in such a way as to obtain a material with an improved microstructure, characterised by a significant increase in hardness and strength while maintaining a high electrical conductivity, thus achieving the main goal of reducing electrode wear in the EDM process. As part of the research, a material with an ultrafine-grained structure was obtained with an average grain size of d 2 = 320 nm and a much higher strength of UTS = 645 MPa compared to the material in the initial state ( UTS = 413 MPa). The post-processing treatment (ageing) allowed us to obtain a material with a high electrical conductivity after the HE process, at 78% IACS. The electrodes made of CuCrZr subjected to HE had a reduced electrical discharge wear in relation to electrodes made of the initial material. The best results were obtained for electrodes made of the material subjected to a five-stage HE process combined with ageing at 480 °C for 1 h. The electrical discharge wear in these electrodes was reduced by more than 50% compared to electrodes made of non-deformed copper.

The paper presents an analysis of the impact of plastic deformation using hydrostatic extrusion (HE) on the structural, mechanical and functional properties of pure copper for use as electrodes in the process of electro discharge machining (EDM). As part of the research, copper was subjected to the HE process with the maximum cumulative true strain equal to ɛ cum  = 3.89 obtained in 5 stages. The result was, a refinement of the microstructure with the grains elongated in the direction of extrusion, with a cross-sectional size of d 2  = 228 nm. As the obtained material can be potentially used in the process of electro discharge machining, the copper specimens after the HE process were subjected to a comprehensive analysis to determine the mechanical, physical and functional properties of the material. A significant increase in strength (UTS) and yield strength (YS) of the HE-processed copper was obtained, reaching respectively UTS = 464 MPa and YS = 456 MPa at the maximum strain of ɛ = 3.89. Despite the clear strain-induced strengthening of the material, a very high electrical conductivity of not less than 97% was obtained. The electrodes made of copper after HE process have reduced erosion wear while maintaining a comparable or better quality of the machined surface. The best results were obtained for finish machining, where the electrical discharge wear was lower by 60% compared to the electrode made of non-processed copper. In addition, an improvement in the surface quality after the EDM process by 25% was observed when using the HE-processed electrodes., (© 2023. Springer Nature Limited.)

The first-in-class luminescent dinucleoside phosphate analogs with a [Re 2 (μ-Cl) 2 (CO) 6 (μ-pyridazine)] "click" linker as a replacement for the natural phosphate group are reported together with the synthesis of luminescent adenosine and thymidine derivatives having the [Re 2 (μ-Cl) 2 (CO) 6 (μ-pyridazine)] entity attached to positions 5' and 3', respectively. These compounds were synthesized by applying inverse-electron-demand Diels-Alder and copper(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition reactions in three or four steps. The obtained compounds exhibited orange emission ( λ PL ≈ 600 nm, Φ PL ≈ 0.10, and τ = 0.33-0.61 μs) and no toxicity (except for one nucleoside) to human HeLa cervical epithelioid and Ishikawa endometrial adenocarcinoma cancer cells in vitro . Furthermore, the compounds' ability to inhibit the growth of Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli bacterial strains was moderate and only observed at a high concentration of 100 μM. Confocal microscopy imaging revealed that the "dirhenium carbonyl" dinucleosides and nucleosides localized mainly in the membranous structures of HeLa cells and uniformly inside S. aureus and E. coli bacterial cells. An interesting finding was that some of the tested compounds were also found in the nuclei of HeLa cells.

The hydro-mining technology is considered as a promising method of bituminous coal excavation. The paper presents the results of the in-situ experimental campaign and modelling of hydro-cutting technology application. The proposed innovative technology was tested in terms of the effects of the distance between the outlet of water from the nozzle and a sidewall, pressure of the water jet, as well as the type of a nozzle on hydro-mining effectiveness. The hydro-cutting tests of coal seam performed in the Experimental Mine "Barbara" in Poland proved that the increase in water pressure in the range 20-40 MPa only slightly affects the coal face structure, while high pressure, of 80-100 MPa, has a significant impact on a coal face structure. The experimental results also showed the major effects of operating time as well as the distance of the water jet on the effectiveness of coal face mining., (© 2023. The Author(s).)

The study aimed to examine the effect of the hydrostatic extrusion (HE) process on the machinability of Ti grade 2 (Ti) in the turning process. After the deformation with true strain ɛ = 2.28, the microstructure was significantly refined to a grain size of 100 nm, resulting in an increase in the mechanical properties, UTS strength by 190%, YS yield strength by 230%Cutting forces for Ti in the initial state and after HE were analyzed at cutting depths a p  = 0.3 mm and 0.5 mm, the variables were cutting speed V c (20, 30 and 50 m/min) and feed rate f (0.08 and 0.13 m/s).The impact of the microstructure refinement in Ti after HE on the high cutting depth machinability deterioration (a p  = 0.7 mm) was identified. This phenomenon is particularly noticeable at lower cutting speeds V c  = 20 and 30 m/min at which cutting forces are higher. Application tests of Ti after HE showed a significantly lower susceptibility to buckling during threading. As a result of the tests carried out for the Ti in the initial state, it was not possible to achieve the tolerance of pitch diameter of the thread required by standards, d 2 at two of the three cutting depths tested. In turn, for the Ti after HE, the thread tolerances required by the standards were achieved for all tested cutting depths., (© 2022. The Author(s).)

The study presents an analysis of the influence of the plastic strain rate on the mechanical and structural properties of pure zinc. Thanks to the use of unconventional methods of plastic processing, the process of the equal channel angular pressing (ECAP) and the process of hydrostatic extrusion (HE), the tests were performed in a wide range of plastic strain rates, between 0.04 s -1 and 170 s -1 . Plastic strain rate changes were carried out in the course of the significant plastic strain processes, and not on previously deformed samples. All tests were carried out at a constant value of plastic strain rate, ε ~ 2. A strong influence of the plastic strain rate on changes in the microstructure in zinc was observed during the tests. For the rates in the range of 0.04 s -1 to 0.53 s -1 its bimodal nature was observed, and in the range of 7 s -1 to 170 s -1 high homogeneity and evenness of grains related to the processes of continuous dynamic recrystallization was noticed. The effect of the strong homogenization of the microstructure was the increase in mechanical properties, yield point and tensile strength to the maximum values of UTS = 194 MPa, YS = 145 MPa at a strain rate of 170 s -1 . Compared to the material with a bimodal microstructure, an over seven-fold increase in the elongation value was observed.

The global spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has called for an urgent need for dedicated antiviral therapeutics. Metal complexes are commonly underrepresented in compound libraries that are used for screening in drug discovery campaigns, however, there is growing evidence for their role in medicinal chemistry. Based on previous results, we have selected more than 100 structurally diverse metal complexes for profiling as inhibitors of two relevant SARS-CoV-2 replication mechanisms, namely the interaction of the spike (S) protein with the ACE2 receptor and the papain-like protease PL pro . In addition to many well-established types of mononuclear experimental metallodrugs, the pool of compounds tested was extended to approved metal-based therapeutics such as silver sulfadiazine and thiomersal, as well as polyoxometalates (POMs). Among the mononuclear metal complexes, only a small number of active inhibitors of the S/ACE2 interaction was identified, with titanocene dichloride as the only strong inhibitor. However, among the gold and silver containing complexes many turned out to be very potent inhibitors of PL pro activity. Highly promising activity against both targets was noted for many POMs. Selected complexes were evaluated in antiviral SARS-CoV-2 assays confirming activity for gold complexes with N-heterocyclic carbene (NHC) or dithiocarbamato ligands, a silver NHC complex, titanocene dichloride as well as a POM compound. These studies might provide starting points for the design of metal-based SARS-CoV-2 antiviral agents., (© 2021 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

This paper presents the effect of severe plastic deformation obtained using the cold hydrostatic extrusion (HE) method on the mechanical and structural properties of polyamide 6 (PA6). As a result of the plastic strain, a significant increase in ultimate tensile strength and tensile modulus were observed. Tensile strength rose by almost 500%, up to the level of 508 MPa, whereas the tensile modulus rose by about 65%. Flexural modulus increase was also observed to 3230 MPa, i.e., by approx. 160%. As a result of high plastic deformation, the structure of the polyamide 6 changed significantly, as evidenced by its fibrous nature as presented in the results of the scanning electron microscopy inspection (SEM). The surface quality of products investigated was tested using profilometry.