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  • THE MELT FLOWABILITY AND TENSILE PERFORMANCE OF POLY (-CAPROLACTONE)/BREWERS’ SPENT GRAIN COMPOSITES AS A FUNCTION OF FILLER MODIFICATION
    • Aleksander Hejna
    2020 Pełny tekst

    Nowadays, it is essential to reduce the environmental impact of products and technologies. Such an approach should be highlighted in all research activities. In the case of polymer composites, it can be realized by introducing by-products or waste materials as fillers. An auspicious example of such material is the brewers’ spent grain, the major byproduct of the beer production. Its chemical composition, relatively similar to conventional lignocellulose fillers, enables its application to manufacturing wood-polymer composites. However, to enhance its compatibility with polymer matrices, it could be modified. Therefore, in the presented paper, the impact of the extrusion grinding of brewers’ spent grain on the processing and mechanical performance of polymer composites was evaluated.

  • The Method of Selecting the Interval of Functional Tests Taking into Account Economic Aspects and Legal Requirements
    • Jan Piesik
    • Emilian Piesik
    • Marcin Śliwiński
    2020 Pełny tekst Journal of Automation, Mobile Robotics and Intelligent Systems - JAMRIS

    The article discusses the problem of choosing the optimal frequency of functional tests, taking into account the reliability and law requirements, but also the impact of business aspects in the company. The subject of functional test interval is well described for purposes of the process industry. Unfortunately, this is not the case for the machinery safety functions with low demand mode. This is followed by a presentation of the current business approach, which, in order to achieve industrial excellence, monitor their performance through the appropriate selection of key performance indicators. In addition, companies are increasingly exploring potential risks in the following areas: new challenges in advanced risk management, including the perception of the company’s facilities as a safe workplace insight of customers and business partners. Eliminating potential hazards is increasingly taking into account, especially the impact of human activity and its interaction with machines. The case study has been presented based on the machines used for the production of tire semi-finished products. In this article, the authors propose a solution for selecting the interval of functional tests of safety functions and additional machine protection measures as a compromise to achieve satisfactory results in terms of safety requirements, performance and legal requirements.

  • The Neural Knowledge DNA Based Smart Internet of Things
    • Haoxi Zhang
    • Fei Li
    • Juan Wang
    • Zuli Wang
    • Lei Shi
    • Cesar Sanin
    • Edward Szczerbicki
    2020 Pełny tekst CYBERNETICS AND SYSTEMS

    ABSTRACT The Internet of Things (IoT) has gained significant attention from industry as well as academia during the past decade. Smartness, however, remains a substantial challenge for IoT applications. Recent advances in networked sensor technologies, computing, and machine learning have made it possible for building new smart IoT applications. In this paper, we propose a novel approach: the Neural Knowledge DNA based Smart Internet of Things that enables IoT to extract knowledge from past experiences, as well as to store, evolve, share, and reuse such knowledge aiming for smart functions. By catching decision events, this approach helps IoT gather its own daily operation experiences, and it uses such experiences for knowledge discovery with the support of machine learning technologies. An initial case study is presented at the end of this paper to demonstrate how this approach can help IoT applications become smart: the proposed approach is applied to fitness wristbands to enable human action recognition.

  • The New Klebsiella pneumoniae ST152 Variants with Hypermucoviscous Phenotype Isolated from Renal Transplant Recipients with Asymptomatic Bacteriuria-Genetic Characteristics by WGS.
    • Magdalena Wysocka
    • Roxana Zamudio
    • Marco R Oggioni
    • Justyna Gołębiewska
    • Aleksandra Dudziak
    • Beata Krawczyk
    2020 Pełny tekst Genes

    Klebsiella pneumoniae (Kp) is one of the most important etiological factors of urinary tract infections in renal transplant (RTx) recipients. We described the antimicrobial susceptibility phenotypes and genomic features of two hypermucoviscous (HM) Kp isolates recovered from RTx recipients with asymptomatic bacteriuria (ABU). Using whole genome sequencing (WGS) data, we showed that the strains belong to the ST152 lineage with the KL149 capsular serotype, but without rmpA/magA genes, which is typical for HM+ hypervirulent Kp. These new strains carried virulence-associated genes that predispose for urinary tract infections (UTIs). Likewise, both strains carried the ecp gene encoding pilus common for extended-spectrum β-lactamase (ESBL) Escherichia coli. Although the two ST152 isolates were closely related and differed by only nine single nucleotide polymorphisms (SNPs) in their chromosomes, they had different plasmid compositions and chromosomal elements, with isolate KP28872 carrying an ESBL plasmid and an integrative conjugative element. These two isolates are an example of the high plasticity of the K. pneumoniae accessory genome. The identification of patients with ABU matched with the correct epidemiological profiling of isolates could facilitate interventions to prevent or rapidly treat K. pneumoniae infections.

  • The new silica-based coated SPME fiber as universal support for the confinement of ionic liquid as an extraction medium
    • Karolina Konieczna
    • Kateryna Yavir
    • Mansoureh Kermani
    • Aleksandra Mielewczyk-Gryń
    • Adam Kloskowski
    2020 SEPARATION AND PURIFICATION TECHNOLOGY

    The new silica-based SPME fiber coating is reported for the first time as universal support purposed to confinement of ionic liquid as an extraction medium. Fiber coating was prepared by the sol-gel process, using potassium silicate (K2SiO3) as a precursor and dimethylformamide (DMF) as a pore-forming medium. The concept of synthesis assumes obtaining a solid porous material on the surface of the glass rod and, being characterized by high porosity, mechanical strength, and uniformity of shape. In the course of the research, several parameters were optimized, like the type of silica precursor, drying steps, time and temperature of aging. Properties of obtained coatings were evaluated using optical and scanning electron microscopies and thermal adsorption/desorption measurements. Finally, the ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate [C2C1IM][BF4] was immobilized in silica pores of the prepared fiber. The usefulness of the obtained SPME silica-IL fibers was investigated by its utilization in model analytical procedures. Robustness of produced fibers is supported by high fiber-to-fiber reproducibility (%) as well as by a long lifetime reaching over 50 extraction/desorption cycles.

  • The New Test Procedure for Group-Type Composition of Base Oils of Lubricating Oils, Especially Emitted into the Environment
    • Paulina Nowak
    • Karolina Kucharska
    • Marian Kamiński
    2020 Pełny tekst ENERGIES

    Mineral base oil, a product of multistep fine refining of the relevant fractions from vacuum distillation of crude oil, is a main component of so-called mineral lubricating oils containing aliphatic and alicyclic substituted aromatic hydrocarbons, i.e., derivatives of benzene and biphenyl. Mineral lubricating oil is composed mostly of mineral base oil and a low amount of enriching additives, most often products of advanced organic chemical technology. The application of mineral lubricating oils in open cutting systems has a very negative impact on environment and on the operator’s health. This work presents a simple, cheap and fast methodology allows identification of the group-type composition of base oil in lubricating oil and to estimate the content or total absence of base oil of mineral and vegetable origin in lubricating oil. The first step of the test is an in-situ screening for fluorescence of petroleum fraction under the 365 nm light. The next is the performance of infrared spectra with Fourier transformation (FT-MIR) to identify and estimate the content of vegetable oil and its derivatives and the performance of UV-Vis spectra to identify and determine the content of aromatic hydrocarbons, as well as dyes present in the lubricating oil. The last stage is normal phase thin layer chromatography (NP-TLC) using different visualization methods to evaluate the group-type composition of lubricating oil. Effectivity of the developed procedure has been confirmed during control of group-type composition evaluation of lubricating oils in cutting systems. The procedure can be also applied with respect to different oil matrices.

  • The occurrence and role of Nitrospira in nitrogen removal systems
    • Mohamad-Javad Mehrani
    • Dominika Sobotka
    • Przemysław Kowal
    • Sławomir Ciesielski
    • Jacek Mąkinia
    2020 Pełny tekst BIORESOURCE TECHNOLOGY

    Application of the modern microbial techniques changed the paradigm about the microorganisms performing nitrification. Numerous investigations recognized representatives of the genus Nitrospira as a key and predominant nitrite-oxidizing bacteria in biological nutrient removal systems, especially under low dissolved oxygen and substrate conditions. The recent discovery of Nitrospira capable of performing complete ammonia oxidation (comammox) raised a fundamental question about the actual role of Nitrospira in both nitrification steps. This review summarizes the current knowledge about morphological, physiological and genetic characteristics of the canonical and comammox Nitrospira. Potential implications of comammox for the functional aspects of nitrogen removal have been highlighted. The complex meta-analysis of literature data was applied to identify specific individual variables and their combined interactions on the Nitrospira abundance. In addition to dissolved oxygen and influent nitrogen concentrations, temperature and pH may play an important role in enhancing or suppressing the Nitrospira activity.

  • The ONETEP linear-scaling density functional theory program
    • Joseph C. A. Prentice
    • Jolyon Aarons
    • James C. Womack
    • Alice E. A. Allen
    • Lampros Andrinopoulos
    • Lucian Anton
    • Robert A. Bell
    • Arihant Bhandari
    • Gabriel A. Bramley
    • Robert J. Charlton
    • Rebecca J. Clements
    • Daniel J. Cole
    • Gabriel Constantinescu
    • Fabiano Corsetti
    • Simon Dubois
    • Kevin K. B. Duff
    • José María Escartín
    • Andrea Greco
    • Quintin Hill
    • Louis P. Lee
    • Edward Linscott
    • David D. O’Regan
    • Maximillian J. S. Phipps
    • Laura Ratcliff
    • Álvaro Ruiz Serrano
    • Edward W. Tait
    • Gilberto Teobaldi
    • Valerio Vitale
    • Nelson Yeung
    • Tim J. Zuehlsdorff
    • Jacek Dziedzic
    • Peter Haynes
    • Nicholas Hine
    • Arash Mostofi
    • Mike Payne
    • Chris-Kriton Skylaris
    2020 Pełny tekst JOURNAL OF CHEMICAL PHYSICS

    We present an overview of the ONETEP program for linear-scaling density functional theory (DFT) calculations with large basis set (planewave) accuracy on parallel computers. The DFT energy is computed from the density matrix, which is constructed from spatially localized orbitals we call Non-orthogonal Generalized Wannier Functions (NGWFs), expressed in terms of periodic sinc (psinc) functions. During the calculation, both the density matrix and the NGWFs are optimized with localization constraints. By taking advantage of localization, ONETEP is able to perform calculations including thousands of atoms with computational effort, which scales linearly with the number or atoms. The code has a large and diverse range of capabilities, explored in this paper, including different boundary conditions, various exchange– correlation functionals (with and without exact exchange), finite electronic temperature methods for metallic systems, methods for strongly correlated systems, molecular dynamics, vibrational calculations, time-dependent DFT, electronic transport, core loss spectroscopy, implicit solvation, quantum mechanical (QM)/molecular mechanical and QM-in-QM embedding, density of states calculations, distributed multipole analysis, and methods for partitioning charges and interactions between fragments. Calculations with ONETEP provide unique insights into large and complex systems that require an accurate atomic-level description, ranging from biomolecular to chemical, to materials, and to physical problems, as we show with a small selection of illustrative examples. ONETEP has always aimed to be at the cutting edge of method and software developments, and it serves as a platform for developing new methods of electronic structure simulation. We therefore conclude by describing some of the challenges and directions for its future developments and applications.

  • The Palais–Smale condition for the Hamiltonian action on a mixed regularity space of loops in cotangent bundles and applications
    • Luca Asselle
    • Maciej Starostka
    2020 Pełny tekst CALCULUS OF VARIATIONS AND PARTIAL DIFFERENTIAL EQUATIONS

    We show that the Hamiltonian action satisfies the Palais-Smale condition over a “mixed regular- ity” space of loops in cotangent bundles, namely the space of loops with regularity H^s, s ∈ (1/2, 1), in the baseand H^{1−s} in the fiber direction. As an application, we give a simplified proof of a theorem of Hofer-Viterbo on the existence of closed characteristic leaves for certain contact type hypersufaces in cotangent bundles.

  • The performance of ETFs on developed and emerging markets with consideration of regional diversity
    • Krystian Zawadzki
    2020 Pełny tekst Quantitative Finance and Economics

    This study evaluates the performance of Exchange-Traded Funds (ETFs) by using various tracking error calculation approaches. The aim of the paper is, on the one hand, an evaluation of the performance of ETFs relative to their benchmarking indexes and, on the other, an endeavour to specify any relationship between this performance and both geographical location and the degree of market development. The research was conducted on the basis of 18 different ETFs issued by iShares, six for each of three regions: both Americas, Asia and Europe. The sole criterion for ETF’s selection was the benchmark. All data were collected with daily frequency. They range from January 2013 to December 2019. The results indicate that ETFs do not mimic their corresponding indexes well. Calculated tracking errors do not equal zero and are often significantly negative. Furthermore, the value of tracking errors depends on the region and the degree of market development.

  • The Possibilities of Improving the Fatigue Durabilityof the Ship Propeller Shaft by Burnishing Process
    • Stefan Dzionk
    • Włodzimierz Przybylski
    • Bogdan Ścibiorski
    2020 Pełny tekst Machines

    Heavily loaded structural elements operating in a corrosive environment are usuallyquickly destroyed. An example of such an element is a ship propeller operating in a seawaterenvironment. This research presents a fatigue resistance test performed on elements operating inseawater. Different processing parameters applied on the samples in particular were compared withthe specimens whose surface had been burnished differently and they were compared to specimenswith a grinded surface. The research shows that the structural elements whose surface has beenburnished can have up to 30% higher fatigue strength in a seawater environment than the elementswhose surface has been grinded. During burnishing, an important feature of the process is the degreeof cold rolling of the material. The resistance of the component to fatigue loads increases only to acertain level with increasing the degree of the cold rolling. Further increasing the degree of coldrolling reduces the fatigue strength. Introducing additional stresses in the components (e.g., assemblystresses) reduces the fatigue strength of this component in operation and these additional stressesshould be accounted for while planning the degree of the cold rolling value. A device that allowsfor simultaneous turning and shaft burnishing with high slenderness is presented in the appendixof this article. This device can be connected to the computerized numerical control system andexecuted automatic process according to the machining program; this solution reduces the number ofoperations and cost in the process

  • The Potential of Improving Air Quality by Urban Mobility Management: Policy Guidelines and a Case Study
    • Joanna Badach
    2020 Pełny tekst IOP Conference Series: Earth and Environmental Science

    There is a growing recognition among planners and policy makers that proper transformation of urban mobility systems is crucial to the reduction of air pollution emission. The main objective of the work was to review the current urban mobility strategies in the city of Gdańsk, Poland in terms of their potential for the improvement of urban air quality. Firstly, general policy guidelines for mobility systems were formulated based on a review of recent relevant studies and existing solutions from various European and Asian cities. Then the main spatial characteristics of the transport system and mobility patterns in Gdańsk were determined and visualised by means of GIS-based tools, supported by the analysis of local urban and environmental planning documents. The current air quality status in Gdańsk was also described. Subsequently, the policies proposed in two documents for the urban mobility management in Gdańsk were identified and cross-compared with the previously reviewed solutions from other cities in terms of air quality improvement. The results showed that the strategies for air pollution mitigation are not integrated with the process of urban planning in Gdańsk to a sufficient degree. Finally, some recommendations were also suggested to improve the current strategies.

  • The power of personal brand authenticity and identification: top celebrity players’ contribution to loyalty toward football
    • Wioleta Kucharska
    • Ilenia Confente
    • Federico Brunetti
    2020 Pełny tekst Journal of Product & Brand Management

    Purpose: In the current era of fake news, illusions, manipulations, and other artificial attributes of virtuality and reality, authenticity is a virtue that people highly appreciate. This study examines the influence of the personal brand authenticity of top football players on loyalty to the football discipline in general, via the mediation of personal brand identification. Design: Based on data collected from a convenience sample of 562 respondents from Poland via an electronic survey and analyzed using the structural equation modeling method this study explored, first, the influence of top football players’ personal brand authenticity on consumers’ identification with these football players, and second, how this identification may lead to enhancing loyalty to the football discipline. Finally, it verified how the loyalty effect (attitudinal and behavioral) varies across different categories of spectators. Originality: This study presents evidence that the personal authenticity of football celebrities to measure loyalty to the football discipline in general, as mediated by personal brand identification. Moreover, this study proves that the loyalty to football driven by the personal brand authenticity of football stars differs between spectators’ categories, and it differs from the loyalty driven by clubs. Findings: Personal brand identification with authentic football stars is a focal factor enabling the creation of loyalty (attitudinal and behavioral) to the whole discipline. Consumers’ perceptions of the authenticity of the personal brands of football players play a role in increasing identification with these personal brands. This identification is essential in achieving loyalty to football as a sports discipline via football celebrities. Implications: Football players perceived as authentic are evaluated more positively, leading to consumer identification with these players, which, in turn, increases consumers’ loyalty to football. Thus, the presence of authentic, skilled players is important for football, but the actual loyalty effect from authenticity can be achieved only by identification. Therefore, football 3 requires exceptional, strong stars who reflect a set of desired personal values. Further research is needed to identify the desired set of values that leads to identification with football stars.

  • The preparation and evaluation of core-shell magnetic dummy-template molecularly imprinted polymers for preliminary recognition of the low-mass polybrominated diphenyl ethers from aqueous solutions
    • Mariusz Marć
    • Piotr Paweł Wieczorek
    2020 Pełny tekst SCIENCE OF THE TOTAL ENVIRONMENT

    The design, preparation process, binding abilities, morphological characteristic and prospective field of application of dummy-template magnetic molecularly imprinted polymer (DMMIP) for preliminary recognition of the selected low-mass polybrominated diphenyl ethers (PBDE-47 and PBDE-99) from aquatic environment were investigated. The surface of iron oxide (Fe3O4) nanopowder (50-100 nm particles size) was modified with tetraethoxysilane and next prepared Fe3O4@SiO2 particles were dispersed in anhydrous toluene functionalized by (3-aminopropyl)triethoxysilane. Finally, MIPs' thin film layer on the surface of Fe3O4@SiO2@NH2 was formed in acetonitrile as a solvent solution, using ethylene glycol dimethacrylate as the cross-linker, building monomer, 1,1′-Azobis(cyclohexanecarbonitrile) as the radical initiator, methacrylic acid as a functional monomer and 4,4'- Dihydroxydiphenyl ether as the dummy template molecule as a structural analogue of low-mass PBDEs. To characterize the chemical structure of prepared DMMIPs, the Fourier transform infrared spectroscopy analysis was performed. The specific surface area of the developed sorbent was estimated using Brauner-Emmet-Teller nitrogen adsorption/desorption analysis. To assess the average pore sizes, pore diameters and pore volumes of the prepared sorbent, the Barret-Joyner-Halenda technique was applied. The average values of imprinting factor for PBDE-47 and PBDE-99 were 11.3 ± 1.6 and 13.7 ± 1.2, respectively. The average value of recovery of PBDE-47 and PBDE-99 for developed DMMIPs from modelling water : methanol solution were 85.4 ± 6.7% and 86.4 ± 9.4%, respectively. In a case of spiked distilled water, tap water as well as local river water the calculated recovery values ranged from 65%% up to 82% and from 33% up to 76% for PBDE-47 and PBDE-99, respectively. Following the preliminary research on selected water samples, the proposed combination of imprinting technology and core–shell materials with magnetic properties might be considered as a promising sorption tool used for targeted recognition of low-mass PBDEs in aquatic solutions.

  • The Product of Matrix Metalloproteinase Cleavage of Doxorubicin Conjugate for Anticancer Drug Delivery: Calorimetric, Spectroscopic, and Molecular Dynamics Studies on Peptide–Doxorubicin Binding to DNA
    • Kamila Butowska
    • Krzysztof Żamojć
    • Mateusz Kogut
    • Witold Kozak
    • Dariusz Wyrzykowski
    • Wiesław Wiczk
    • Jacek Czub
    • Jacek Piosik
    • Janusz Rak
    2020 Pełny tekst INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

    Matrix metalloproteinases (MMPs) are extracellular matrix degradation factors, promoting cancer progression. Hence, they could provide an enzyme-assisted delivery of doxorubicin (DOX) in cancer treatment. In the current study, the intercalation process of DOX and tetrapeptide-DOX, the product of the MMPs' cleavage of carrier-linked DOX, into dsDNA was investigated using stationary and time-resolved fluorescence spectroscopy, UV-Vis spectrophotometry and isothermal titration calorimetry (ITC). The molecular dynamics (MD) simulations on the same tetrapeptide-DOX…DNA and DOX…DNA systems were also performed. The undertaken studies indicate that DOX and tetrapeptide-DOX can effectively bond with dsDNA through the intercalation mode; however, tetrapeptide-DOX forms less stable complexes than free DOX. Moreover, the obtained results demonstrate that the differences in DNA affinity of both forms of DOX can be attributed to different intercalation modes. Tetrapeptide-DOX shows a preference to intercalate into DNA through the major groove, whereas DOX does it through the minor one. In summary, we can conclude that the tetrapeptide-DOX intercalation to DNA is significant and that even the lack of non-specific proteases releasing DOX from the tetrapeptide conjugate, the presence of which is suggested by the literature for the efficient release of DOX, should not prevent the cytostatic action of the anthracycline.

  • The Proposition of an Automated Honing Cell with Advanced Monitoring
    • Adam Barylski
    • Piotr Sender
    2020 Pełny tekst Machines

    Honing of holes allows for small shape deviation and a low value of a roughness profile parameter, e.g., Ra parameter. The honing process heats the workpiece and raises its temperature. The increase in temperature causes thermal deformations of the honed holes. The article proposes the construction of a honing cell, containing in addition to CNC honing machine: thermographic camera, sound intensity meter, and software for collecting and analyzing data received during machining. It was proposed that the level of sound intensity obtained during honing could be monitored continuously and that the images from a thermographic camera could be analyzed on-line. These analyses would be aimed at supervising honing along with the on-line correction of machining parameters. In addition to the oil cooler, the machining cell may have an automatic selection of the grain trajectory shape, with specified value of the radii of curvature of the abrasive grain trajectories, according to the wall thickness of the honed workpiece, which will result in reducing the temperature generated during honing. Automated honing cell can mostly increase honing process efficiency. Simulations in FlexSim showed the possibility of increasing the efficiency of the honing process more than 20 times.

  • The pulsed laser ablation synthesis of colloidal iron oxide nanoparticles for the enhancement of TiO2 nanotubes photo-activity
    • Piotr Kupracz
    • Emerson Coy
    • Katarzyna Grochowska
    • Jakub Karczewski
    • Jakub Rysz
    • Katarzyna Siuzdak
    2020 APPLIED SURFACE SCIENCE

    The rapid, only a few minutes long synthesis of FeO, Fe3O4, and Fe2O3nanoparticles mixture utilizing the pulsedlaser ablation using simply pure iron target and water was demonstrated. The size and crystal phase of Fe-basedNPs were characterized using DLS and HR-TEM techniques, respectively. The metastable suspension of FeO,Fe3O4, and Fe2O3nanoparticles was used to the decoration of anodized TiO2nanotubes (TiO2-NTs) by means ofthe ultrasonic bath. SEM inspection confirms preservation of the ordered morphology even upon 60 min longexposition to the ultrasounds whereas TOF SIMS indicated penetration of iron species down to the TiO2-NTsbase. Finally, the electrochemical investigation of decorated and bare TiO2-NTs has shown a response typical forFe2+/Fe3+iron species and the boosted activity towards oxygen evolution reaction in the anodic regime. As ofhigh importance, for the 30 min long ultrasound-assisted modification, the photocurrent was enhanced almost2.5 times comparing to the pristine material exposed to the solar light, although differences in optical propertieswere negligible. Taking into account outstanding activity namely response upon irradiation and effectiveness ofwater splitting, the proposed approach can be regarded as a facile one generating much less waste in comparisonto typical wet-chemistry methods.

  • The Quantum Efficiency Roll-Off Effect in Near-Infrared Organic Electroluminescent Devices with Iridium Complexes Emitters
    • Wojciech Mróz
    • Sagar Kesarkar
    • Alberto Bossi
    • Daniel Pelczarski
    • Piotr Grygiel
    • Waldemar Stampor
    2020 Pełny tekst Materials

    The electroluminescence quantum efficiency roll-off in iridium(III)-based complexes, namely Ir(iqbt)2(dpm) and Ir(iqbt)3(iqbt=1 (benzo[b]thiophen-2-yl)-isoquinolinate, dpm=2,2,6,6-tetramethyl-3,5-heptanedionate) utilized as near-infrared emitters in organic light emitting diodes with remarkable external quantum efficiencies, up to circa 3%, 1.5% and 1%, are measured and analyzed. With a 5–6 weight % of emitters embedded in a host matrix, the double-layer solution-processed structure as well as analogous three-layer one extended by a hole-conducting film are investigated. The triplet-polaron, the Onsager electron-hole pair dissociation and the triplet-triplet annihilation approaches were used to reproduce the experimental data. The mutual annihilation of triplets in iridium emitters was identified as prevailingly controlling the moderate roll-off,with the interaction between those of iridium emitters and host matrixes found as being less probable. Following the fitting procedure, the relevant rate constant was estimated to be(0.5−12)×10−12cm3/s,values considered to be rather too high for disordered organic systems, which was assigned to the simplicity of the applied model. A coexistence of some other mechanisms is therefore inferred, ones, however, with a less significant contribution to the overall emission quenching.

  • The Quaternization Reaction of 5-O-Sulfonates of Methyl 2,3-o-Isopropylidene-β-D-Ribofuranoside with Selected Heterocyclic and Aliphatic Amines
    • Barbara Dmochowska
    • Rafał Ślusarz
    • Jarosław Chojnacki
    • Justyna Samaszko-Fiertek
    • Janusz Madaj
    2020 Pełny tekst MOLECULES

    The synthesis of N-((methyl 5-deoxy-2,3-O-isopropylidene-β-D-ribofuranoside)-5-yl) ammonium salts are presented. To determine the effect of the nucleophile type and outgoing group on the quaternization reaction, selected aliphatic and heterocyclic aromatic amines reacted with: methyl 2,3-O-isopropylidene-5-O-tosyl-β-D-ribofuranoside or methyl 2,3-O-isopropylidene-5-O-mesyl-β-D -ribofuranoside or methyl 2,3-O-isopropylidene-5-O-triflyl-β-D-ribofuranoside were performed on a microscale. High-resolution 1H- and13C-NMR spectral data for all new compounds were recorded. Additionally, the single-crystal X-ray diffraction analysis for methyl 2,3-O-isopropylidene-5-O-mesyl-β-D-ribofuranoside and selected in silico interaction models are reported

  • The Reactivity of Phosphanylphosphinidene Complexes of Transition Metals Toward Terminal Dihaloalkanes
    • Anna Ordyszewska
    • Natalia Szynkiewicz
    • Jarosław Chojnacki
    • Jerzy Pikies
    • Rafał Grubba
    2020 Pełny tekst INORGANIC CHEMISTRY

    The reactivities of phosphanylphosphinidene complexes [(DippN)2W(Cl)(η2-P−PtBu2)]− (1), [(pTol3P)2Pt(η2- P=PtBu2)] (2), and [(dppe)Pt(η2-P=PtBu2)] (3) toward dihaloalkanes and methyl iodide were investigated. The reactions of the anionic tungsten complex (1) with stochiometric Br(CH2)nBr (n = 3, 4, 6) led to the formation of neutral complexes with a tBu2PP(CH2)3Br ligand or neutral dinuclear complexes with unusual tetradentate tBu2PP(CH2)nPPtBu2 ligands (n = 4, 6). The methylation of platinum complexes 2 and 3 with MeI yielded neutral or cationic complexes bearing side-on coordinated tBu2P−P-Me moieties. The reaction of 2 with I(CH2)2I gave a platinum complex with a tBu2P-P-I ligand. When the same dihaloalkane was reacted with 3, the P-P bond in the phosphanylphosphinidene ligand was cleaved to yield tBu2PI, phosphorus polymers, [(dppe)PtI2] and C2H4. Furthermore, the reaction of 3 with Br(CH2)2Br yielded dinuclear complex bearing a tetraphosphorus tBu2PPPPtBu2 ligand in the coordination sphere of the platinum. The molecular structures of the isolated products were established in the solid state and in solution by single-crystal X-ray diffraction and NMR spectroscopy. DFT studies indicated that the polyphosphorus ligands in the obtained complexes possess structures similar to free phosphenium cations tBu2P+=P−R (R = Me, I) or (tBu2P+=P)2.