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1

Microplasma spraying of hydroxyapatite coatings on additive manufacturing titanium implants with trabecular structures

Kadyroldina Albina, Alontseva Dayra, Voinarovych Sergey, Łatka Leszek, Kyslytsia Oleksandr, Azamatov Bagdat, Khozhanov Aleksandr, Prokhorenkova Nadezhda, Zhilkashinova Almira, Burburska Svitlana

Materials Science Poland

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2022

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Vol. 40, No. 4

28--42

EN

This paper presents new results of microplasma spraying (MPS) of laboratory-synthesized hydroxyapatite (HA) powder coatings onto trabecular substrates obtained by selective laser melting (SLM) of a certified titanium medical alloy powder. The aim of the study was to establish the possibility of combining the technologies of MPS and additive manufacturing (AM) for the possible production of custom-designed implants with increased surface biocompatibility, as well as to establish the MPS parameters that ensure chemical purity of the HA coating and satisfactory adhesion of the coatings to the substrate. The structural-phase compositions of the initial HA powder and the plasma-sprayed HA coating were studied by X-ray diffraction analysis and transmission electron microscopy, and the adhesion strength of the coating was tested according to the F1147 standard of the American Society for Testing and Materials (ASTM). The main results of the study are the following: the application of the MPS technology for HA coating with an average thickness of 150±50 μm on trabecular substrates obtained by the SLM method has been shown. The parameters of MPS of HA coatings onto titanium implants with a trabecular surface have been established. It is also proved that using the appropriate MPS parameters, it is possible to obtain a HA coating with a 95% level of HA phases, 93% level of crystallinity, and the adhesion strength to the trabecular substrate of 24.7±5.7 MPa, which complies with the requirements of the international medical standard (International Organization for Standardization [ISO] 13779-2:2018). These results are of significance for a wide range of researchers developing plasma spray technologies for the manufacture of biocompatible coatings.

2

Evaluation of the SPECT radioisotope perfusion scan in the detection of ischemic heart disease

Zdanowski Paweł, Cacko Marek, Rabczenko Daniel, Kochman Janusz, Królicki Leszek

Inżynier i Fizyk Medyczny

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2022

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Vol. 11, nr 2

129--135

EN

Objectives: The aim of the study is to determine the diagnostic value of myocardial perfusion scintigraphy (MPS) depending on the location and size of stenosis of a coronary vessel or vessels. Methods: Results of examinations of patients hospitalized in two hospital departments of the same medical facility were analyzed. Retrospective research material consisted of results obtained for 200 patients with suspected ischemic heart disease (coronary artery disease - CAD). From this group, 83 examinations were selected where results of coronary angiography and perfusion scintigraphy (MPS) were available. The following tests were used for statistical studies: t-Student, Chi2, Fisher- -Sendecor, Kruskal-Wallis and Willcoxon. The use of these tests allowed for: – determination of predictive factors favoring development of ischemic heart disease in the analyzed group of patients, – determination of sensitivity and specificity of MPS, taking the coronary examination as the “gold standard”, – assessment of usefulness of the MPS imaging depending on location of a stenosis within the main coronary vessels, – evaluation of usefulness of MPS in detection of a multivessel disease. Results: I n t he a nalyzed g roup o f p atients, a rterial h ypertension was the main factor predisposing to CAD (p = 0.016). The highest sensitivity of MPS in the diagnosis of ischemia was found in the group of patients with stenosis of the right coronary artery (RCA) (p = 0.029) and the circumflex (Cx) and marginal (MB) branches (p = 0.028). A comparative analysis was performed between the degree of narrowing of the above vessels and the degree of perfusion disorders in the MPS study. There was a correlation between the severity of ischemia in MPS and the degree of stenosis in both RCA (p = 0.011, 95% sensitivity (83.1 - 99.4 CI; negative predictive value 83.3%) and the Cx/MB complex (p = 0.044, sensitivity 94.7% ( 83.1 - 99.4 CI), negative predictive value - 83.3%). There was a correlation between the result of the MPS perfusion scan and disease of two or three coronary vessels. There was a 97% agreement between the presence of permanent or transient defects in MPS and the presence of stenosis in 2 or 3 coronary vessels exceeding 80% of the vessel lumen. In the group of patients with stenosis ranging between 50-80%, abnormal results of the MPS occurred in 41.7% of patients. Conclusion: The results confirm that myocardial perfusion scintigraphy is a very valuable screening test in patients with suspected CAD. This examination shows high sensitivity also in the group of patients with multivessel disease.

3

Fabrication and characterization of Zr microplasma sprayed coatings for medical applications

Voinarovych Sergii G., Alontseva Darya L., Kyslytsia Oleksandr N., Kaliuzhnyi Sergii, Khozhanov Alexandr R., Krasavin Alexander, Kolesnikova Tatiana

Advances in Materials Science

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2021

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Vol. 21, nr 2(68)

93--105

EN

This paper presents new results of studying the influence of parameters of microplasma spraying (MPS) of Zr wire on the structure of Zr coatings. The coating experiments were accomplished in a two level fractional factorial design. Individual particles of sprayed Zr wire and their splats on the substrate were collected under various spraying parameters (amperage, spraying distance, plasma gas flow rate and wire flow rate) and evaluated by Scanning Electron Microscopy (SEM) to establish the effect of particle size and shape on the coating microstructure. The particles were characterized by measurement of their sizes and the obtained results were evaluated in terms of their degree of melting. This was compared with the experimentally observed coating microstructure type and finally correlated to the investigated coating porosity to select the specific MPS parameters of Zr coatings depositing onto medical implants from Ti alloy. It was found that the main parameters influencing the size of the sprayed Zr particles and the porosity of the Zr coatings are the plasma gas flow rate and amperage. It was demonstrated that it is possible to control the porosity of Zr microplasma coatings in the range from 2.8% to 20.3% by changing the parameters of the MPS. The parameters of microplasma spraying of Zr wire were established to obtain medical implant coatings with porosity up to 20.3% and pore size up to 300 μm.

4

Comparison of cracks criteria MPS, S-Criterion, T-Criterion using a computer program to obtain the angle of fracture propagation

Roman Kamil Krzysztof, Borek Kinga, Mazur Kamila

Inżynieria Materiałowa

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2019

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Vol. 40, nr 6

154--157

EN

The content of the article assumes the description and comparison of three selected criteria of cracks: MPS, S-Criterion and T-Criterion. The analyses carried out were a simulation of the steel cracking process in a dimensionless tensor space, using the components of a stress tensor. The research concerned the analysis of the slot propagation direction in relation to the adopted angle, taking into account the criterion used. Depending on the criterion used, the analysis assumed taking into account various types of gap loads (KI, KII, KIII), which were responsible for the tearing, longitudinal shear and transverse shear successively. Initial stresses have been properly taken into account and transferred to the Cartesian system depending on the type of deformation used. During the analysis, study will be the angle of displacement fractures α, in considered range to π/2. It was noted that the S-criterion for Flat State of Deformation (FSD), had a straight run, with lift of the angle θ was 6.22, including the tolerance of 0.01. The angle of inclination α, was considered taking into account the angles of 0°, 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40° and 45° for each of the analysed criteria. The methods involves the use a dedicated computer program created in the C++ environment. The computational module of the computer program in the form of matrix equations algorithm, analysed the distribution of tensors of occurring stress. The result values are summarized in tabular form and then presented in the form of a graph. The results are purely theoretical, and therefore a dedicated program, because of its severity may contain errors.

PL

W celu predykcji negatywnego zachowania się materiału wykorzystywanego do różnorakiej produkcji zostały wprowadzone schematy badań polegające na założeniach modeli obliczeniowych. Poszczególne analizy polegają na określeniu kąta, pod którym prawdopodobnie będzie przebiegało pęknięcie materiału. Wykorzystując wyniki analiz, charakteryzujących przebieg naprężeń podczas obciążenia szczeliny, można określić propagację oraz trajektorię pęknięć powierzchni. Uwzględnione kryteria pozwalają w pełni opracować rozwiązania zakładanego problemu.

5

Optimization of hydroxyapatite synthesis and microplasma spraying of porous coatings onto titanium implants

Alontseva D. L., Abilev M. B., Zhilkashinova A. M., Voinarovych S. G., Kyslytsia O. N., Ghassemieh E., Russakova A., Łatka L.

Advances in Materials Science

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2018

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Vol. 18, nr 3(57)

79--94

EN

The paper presents the main results of development and optimization of the synthesis of hydroxyapatite and the application of the micro-plasma spraying technique for biocompatible coatings. The hydroxyapatite synthesis was optimized using the mathematical modelling method. Synthesized hydroxyapatite was studied by IR spectrometry and X-ray diffraction analysis for assessment of the compatibility of the chemical and phase composition to the bone tissue. The Ca/P ratio of the obtained hydroxyapatite was 1.65, which is close to that of bone tissue (1.67). To increase the adhesion strength of the HA coating to the surface of the titanium implant, it was suggested to apply a titanium sublayer to the implant surface. Microplasma spraying (MPS) of biocompatible coatings from titanium wires and synthesized HA powders onto substrates made of medical titanium alloy has been carried out. Microplasmatron MPN-004 is used to obtain the two-layer coatings for titanium implants. The two layer coating includes a sub-layer of a porous titanium coating with a thickness in range from 200 up to 300 μm and the porosity level of about 30%, and an upper layer of HA about 100 μm thick with 95% level of HA phases and 93% level of crystallinity. The pore size varies from 20 to 100 μm in both coatings. The paper describes the technology and modes of microplasma deposition of two-layer coatings, including the mode of gas-abrasive treatment of the surface of implants made of titanium alloy before spraying. The synthesized HA powder and the Ti/HA coatings were investigated by optical microscopy and scanning electron microscopy with the energy dispersion analysis and the X-ray diffraction analysis.

6

Wpływ nadsiarczanu i mononadsiarczanu na własności fizykochemiczne osadu czynnego

Chłąd Z., Grübel K., Wacławek S., Przywara L.

Proceedings of ECOpole

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2015

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Vol. 9, No. 2

561--570

PL

Ze względu na wzrastającą ilość osadów ściekowych wymagających zagospodarowania nieustannie poszukuje się nowych metod pozwalających na ich lepsze kondycjonowanie. Do takich metod należy zaliczyć różnego rodzaju sposoby dezintegracji osadów. W podjętych badaniach starano się określić wpływ chemicznej dezintegracji przy pomocy termicznie aktywowanego nadsiarczanu sodu (PDS) i mononadsiarczanu potasu (MPS) na wybrane własności sedymentacyjne i fizykochemiczne osadu ściekowego. W badaniach użyto dawek reagentów PDS i MPS: 0,2; 0,4; 0,6; 0,8 i 1% objętościowych, które aktywowano termicznie w temperaturze 60 i 80ºC przez 30 minut. Wpływ analizowanych substancji na osad czynny starano się wykazać na podstawie zmian wybranych parametrów, takich jak: mętność, uwolniona/rozpuszczona materia organiczna (wyrażone jako rChZT), indeks objętościowy osadu (I.O.O.) i indeks gęstości osadu (I.G.O.). Pod wpływem działania PDS i MPS mętność cieczy nadosadowej zmalała odpowiednio o 90 i 85%. Wraz ze wzrostem dawki reagentów zaobserwowano wzrost wartości rChZT, będącego wskaźnikiem uwolnionej w trakcie dezintegracji materii organicznej. Wartość rChZT w cieczy nadosadowej przy zastosowaniu PDS i MPS wzrosła odpowiednio o 41 i 77%. Zaobserwowano również zmniejszenie indeksu objętościowego osadu (I.O.O.) przy zastosowaniu temperatury aktywowania substancji dezintegrujących równej 80ºC oraz dawce tych substancji równej 1%. W przypadku MPS wartość indeksu objętościowego zmniejszyła się z 37,80 do 16,29 cm3/g po 30 minutach sedymentacji. Natomiast dla PDS nastąpił spadek wartości z 39,49 do 24,66 cm3/g w tym samym czasie.

EN

Due to the increasing amount of sewage sludge requiring management new methods which allow improving sludge conditioning are being sought incessantly. Such methods include different types of sludge disintegration processes. In the present study an attempt was made to determine the influence of thermally activated persulfate (PDS) and monopersulfate (MPS) on the sedimentation and physico-chemical properties of the waste activated sludge (WAS). In this study 0.2, 0.4, 0.6, 0.8, 1% doses of PDS and MPS were used, and they were activated at the temperature of 60 and 80ºC for 30 minutes. The impact of the analyzed substances on WAS was investigated on basis of changes of the selected parameters such as: turbidity, soluble chemical oxygen demand (rCOD), sludge volume index (SVI). Addition of PDS and MPS to the WAS caused decrease of turbidity of supernatant by 90 and 85%, respectively. When the doses of the reactants increased there was also an increase in the SCOD value, being an indicator of the organic matter released during the disintegration. The SCOD value in the supernatant increased with using PDS and MPS by 41 and 77%, respectively. There was also observed decrease of sludge volume index (SVI) after addition of temperature activated (80ºC) PDS and MPS. For highest dose of MPS, SVI decrease from 37.80 to 16.29 cm3/g after 30 min sedimentation. In contrast, for the PDS there was a decrease from 39.49 to 24.66 cm3/g at the same time.

7

Ultrasensitive laser spectroscopy for breath analysis

Wojtas J., Bielecki Z., Stacewicz T., Mikołajczyk J., Nowakowski M.

Opto-Electronics Review

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2012

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Vol. 20, No. 1

26-39

EN

At present there are many reasons for seeking new methods and technologies that aim to develop new and more perfect sensors for different chemical compounds. However, the main reasons are safety ensuring and health care. In the paper, recent advances in the human breath analysis by the use of different techniques are presented. We have selected non-invasive ones ensuring detection of pathogenic changes at a molecular level. The presence of certain molecules in the human breath is used as an indicator of a specific disease. Thus, the analysis of the human breath is very useful for health monitoring. We have shown some examples of diseases' biomarkers and various methods capable of detecting them. Described methods have been divided into non-optical and optical methods. The former ones are the following: gas chromatography, flame ionization detection, mass spectrometry, ion mobility spectrometry, proton transfer reaction mass spectrometry, selected ion flow tube mass spectrometry. In recent twenty years, the optical methods have become more popular, especially the laser techniques. They have a great potential for detection and monitoring of the components in the gas phase. These methods are characterized by high sensitivity and good selectivity. The spectroscopic sensors provide the opportunity to detect specific gases and to measure their concentration either in a sampling place or a remote one. Multipass spectroscopy, cavity ring-down spectroscopy, and photo-acoustic spectroscopy were characterised in the paper as well.

8

Poszukiwanie nowych leków immunosupresyjnych

Dzierzbicka K., Cholewiński G., Iwaszkiewicz-Grześ D., Trzonkowski P.

Wiadomości Chemiczne

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2011

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[Z] 65, 1-2

59-92

EN

Transplantology is getting more and more important in medicine. Development of surgical techniques and immunosuppressive treatment enabled to establish successful transplantations with various organs and tissues. However, allografts are recognized as foreign tissues and stimulate rejection, i.e. a strong immunological response which, if not stopped, results in complete destruction of the transplanted tissue. In order to prevent the rejection patients have to be treated with immunosuppressive drugs after transplantation. Unfortunately, such a damping of immune system poses a risk of cancer or severe infections. The treatment itself is also toxic, notably when applied in a long-term maintenance therapy. Currently, adverse effects of immunosuppressive drugs are recognized as the ones to be involved significantly in chronic rejection and limitation of long survival of grafted tissues. Whereas prevention of acute rejection is mostly successful, there is still no efficient treatment for chronic graft rejection. Reduction of a dose of immunosuppressive drugs or an invention of new active substances is considered the most promising solution. Nowadays, immunosuppressive drugs can be divided into the three main groups: agents which inhibit production of cytokines taking part in cells’ activation (glicocorticosteroids, calcineurine inhibitors, mTOR inhibitors), antiproliferative compounds (azathiopirin, mycophenolate mofetil, mycophenolic acid sodium salt), and antibodies. In this article we present new investigations towards immunosuppressive drugs, their structures and synthetic methods.

9

Replanowanie realizacji projektu techniczno-organizacyjnego w momencie wystąpienia zakłócenia

Łapuńka I., Knosala R.

Zarządzanie Przedsiębiorstwem

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2007

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Vol. 10, nr 1

13-28

EN

The article addresses the issues related to the planning of project realization in the conditions of disturbances. Planning is the major importance of a project because the project involves doing something which has not been done before. As a result, there are relatively more processes in this section. First, the method of the networks plans creation for the technical-organizational project in the conditions of disturbances was presented; next, the disruption in production has been classified and finally, the computer system aided planning of project realization has been shown. Moreover, this paper describes the process of generating alternative plans in the project realization. The treatment of basic information (time and cost) used for evaluating variants of plan as regards criteria is discussed. Global trends have pushed all professional services, including design, toward commoditization. In addition, every industry has come under powerful pressures to work "faster, better and cheaper" - to shorten project realization time and cut production costs while improving quality, as well. In this section, the analysis of activity network in the project management and difficult selection of the best of variant in the planning of technical and organizational project realization are presented. The project plan consists of planning and specification the realization of the project, scheduling, and resource planning for all submodels. It is an instrument for planning, steering and control by the project management. In addition, in a free market economy, productively efficient firms use a cost curves to find the optimal point of production, where they make the most profits. In last part, the article discusses some procedural issues relating to a multicriterial evaluation for the selection of a better variant in the planning of technical and organizational project realization. The multicriterial evaluation based on the criteria proposed by experts or decision-makers in the planning phase, during which it is critical to document the tasks to be completed in a project schedule. In this contribution are two main problems stressed: (1) the treatment of basic information used for evaluating variants of plan as regards criteria; and (2) the creation fuzzy logic membership functions that define the meaning (values) of input/output terms used in the evaluation.

10

Mielenie kamienia wapiennego i wapna palonego w młynach misowo-rolkowych MPS

Reichardt Y.

Cement Wapno Beton

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2005

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R. 10/72, nr 3

138-141

PL

Młyny misowo-rolkowe MPS produkcji Gebr. Pfeiffer są od wielu lat stosowane w przemyśle wapienniczym do suszenia i mielenia kamienia wapiennego, a także do mielenia wapna palonego. Wydajność może mieścić się w zakresie od 5 t/h do 100 t/h przy uziarnieniu produktu gotowego nie przekraczającym 20um lub mieszczącym się w przedziale mniejszym od 200 um. Równocześnie młyny te mogą służyć do wytwarzania piasków wapiennych o uziarnieniu nie przekraczającym 1 mm.

EN

Pfeiffer MPS vertical roller mills have been operating on a large scale for years in the lime industry for combined grinding and drying of limestone and quicklime. Throughput of these plants ranges from 5 t/h to 100 t/h with product fineness rates of less than 20 um to less 200 um. In addition to the fine products, classifier grits with a fineness of up to 1 mm can be obtained.