Publications by authors named "Kotwica K"

The purpose of this study was to experimentally determine the abrasion wear properties of ausferritic ductile iron austempered at 250 °C in order to obtain cast iron of class EN-GJS-1400-1. It has been found that such a cast iron grade makes it possible to create structures for material conveyors used for short-distance transport purposes, required to perform in terms of abrasion resistance under extreme conditions. The wear tests addressed in the paper were conducted at a ring-on-ring type of test rig.

View Article and Find Full Text PDF

The behavioral responses of L. adults to varying blends of synthetic plant volatiles (SPVs) at various concentrations in lieu of single compounds are reported for the first time. For this study, plants were treated with two blends of SPVs at different quantities that act as either attractants or repellents to insects.

View Article and Find Full Text PDF

This short critical review is devoted to the synthesis and functionalization of various types of azaacenes, organic semiconducting compounds which can be considered as promising materials for the fabrication of n-channel or ambipolar field effect transistors (FETs), components of active layers in light emitting diodes (LEDs), components of organic memory devices and others. Emphasis is put on the diversity of azaacenes preparation methods and the possibility of tuning their redox and spectroscopic properties by changing the C/N ratio, modifying the nitrogen atoms distribution mode, functionalization with electroaccepting or electrodonating groups and changing their molecular shape. Processability, structural features and degradation pathways of these compounds are also discussed.

View Article and Find Full Text PDF

Spectroscopic, electrochemical, and structural properties of 2,6-dialkoxy-9,10-anthraquinones (Anth-OC, = 4, 6, 8, 10, and 12) of increasing alkoxy substituents length were investigated. UV-vis spectroscopy showed a substitution-induced bathochromic shift of the least energetic band from 325 nm in the case of unsubstituted anthraquinone to ca. 350 nm for the studied derivatives.

View Article and Find Full Text PDF

A semiconducting molecule containing a thiol anchor group, namely 2-(5-mercaptothien-2-yl)-8-(thien-2-yl)-5-hexylthieno[3,4-]pyrrole-4,6-dione (abbreviated as D-A-D-SH), was designed, synthesized, and used as a ligand in nonstoichiometric quaternary nanocrystals of composition AgInZnS(S) to give an inorganic/organic hybrid. Detailed NMR studies indicate that D-A-D-SH ligands are present in two coordination spheres in the organic part of the hybrid: (i) inner in which the ligand molecules form direct bonds with the nanocrystal surface and (ii) outer in which the ligand molecules do not form direct bonds with the inorganic core. Exchange of the initial ligands (stearic acid and 1-aminooctadecane) for D-A-D-SH induces a distinct change of the photoluminescence.

View Article and Find Full Text PDF

The invasive weed Rumex confertus Willd. (mossy sorrel) is eaten and severely defoliated by oligophagous Gastrophysa viridula Deg. (dock leaf beetle) and Gastrophysa polygoni L.

View Article and Find Full Text PDF

Self-organization in mono- and bilayers on HOPG of two groups of benz[5,6]acridino[2,1,9,8-]acridine derivatives, namely, 8,16-dialkoxybenzo[]benz[5,6]acridino[2,1,9,8-]acridines with an increasing alkoxy substituent length and 8,16-bis(3- or 4- or 5-octylthiophen-2-yl)benzo[]benz[5,6]acridino[2,1,9,8-]acridines, i.e., three positional isomers of the same benzoacridine, is investigated by scanning tunneling microscopy.

View Article and Find Full Text PDF

The presented research is focused on the synthesis of alloyed Ag-In-Zn-S colloidal nanocrystals from a mixture of simple metal precursors such as AgNO, InCl, zinc stearate combined with 1-dodecanethiol (DDT), 1-octadecene (ODE), and sulfur dissolved in oleylamine (OLA). In particular, the focus is on the effect of the solvent (ODE vs 1,2-dichlorobenzene (DCB)) and the type of sulfur precursor (S/OLA vs S/ n-octylamine (OCA)) on the metal precursors reactivates and on the chemical composition, crystal structure, and luminescent properties of the resulting nanocrystals. The replacement of ODE by DCB as a solvent lowers the reactivity of metal precursors and results in a 3-fold decrease of the photoluminescence quantum yields (Q.

View Article and Find Full Text PDF

Ternary Ag-In-S or quaternary Ag-In-Zn-S nanocrystals were prepared from simple precursors (silver nitrate, indium(iii) chloride, zinc stearate in a mixture of DDT and ODE) by injecting a solution of elemental sulfur into OLA. Ternary nanocrystals were modified by depositing either a ZnS or a CdS shell, yielding type I and type II core/shell systems exhibiting photoluminescence QY in the range of 12-16%. Careful optimization of the reaction conditions allowed alloyed quaternary Ag-In-Zn-S nanocrystals exhibiting tunable photoluminescence in the spectral range of 520-720 nm with a QY of 48% and 59% for green and red radiations, respectively, to be obtained.

View Article and Find Full Text PDF

Star-shaped conjugated molecules, consisting of a benzene central unit symmetrically trisubstituted with either oxa- or thiadiazole bithiophene groups, were synthesized as promising molecules and building blocks for application in (opto)electronics and electrochromic devices. Their optical (Eg (opt)) as well as electrochemical (Eg (electro)) band gaps depended on the type of the side arm and the number of solubilizing alkyl substituents. Oxadiazole derivatives showed Eg (opt) slightly below 3 eV and by 0.

View Article and Find Full Text PDF

It is demonstrated that ternary Cu-Fe-S nanocrystals differing in composition (from Cu-rich to Fe-rich), structure (chalcopyrite or high bornite) and size can be obtained from a mixture of CuCl, FeCl3, thiourea and oleic acid (OA) in oleylamine (OLA) using the heating up procedure. This new preparation method yields the smallest Cu-Fe-S nanocrystals ever reported to date (1.5 nm for the high bornite structure and 2.

View Article and Find Full Text PDF

Simple modification of benzo[h]benz[5,6]acridino[2,1,9,8-klmna]acridine-8,16-dione, an old and almost-forgotten vat dye, by reduction of its carbonyl groups and subsequent O-alkylation, yields solution-processable, electroactive, conjugated compounds of the periazaacene type, suitable for the use in organic electronics. Their electrochemically determined ionization potential and electron affinity of about 5.2 and -3.

View Article and Find Full Text PDF

In laboratory conditions, the effect of pro-ecological procedures (application of effective microorganisms and Asahi SL biostimulator) and foraging by insects [cereal leaf beetle (Oulema melanopa L.) and bird cherry-oat aphid (Rhopalosiphum padi (L.)] on the total content of phenolic compounds in winter wheat, was studied.

View Article and Find Full Text PDF

Background: Autologous peripheral blood stem cell transplantation (APBSCT) is the standard of therapy for patients with multiple myeloma and refractory Hodgkin's and non-Hodgkin's lymphomas. Granulocyte colony-stimulating factor (G-CSF) is widely used to accelerate hematopoietic recovery after transplantation and to reduce the morbidity and mortality associated with prolonged neutropenia. Biosimilar G-CSF is approved for the same indications as the originator G-CSF.

View Article and Find Full Text PDF

Exchange of initial, predominantly stearate ligands for pyridine in the first step and butylamine (BA) or 11-mercaptoundecanoic acid (MUA) in the second one was studied for alloyed quaternary Cu-In-Zn-S nanocrystals. The NMR results enabled us to demonstrate, for the first time, direct binding of the pyridine labile ligand to the nanocrystal surface as evidenced by paramagnetic shifts of the three signals attributed to its protons to 7.58, 7.

View Article and Find Full Text PDF

Indanthrone, an old, insoluble dye can be converted into a solution processable, self-assembling and electroluminescent organic semiconductor, namely tetraoctyloxydinaptho[2,3-a:2',3'-h]phenazine (P-C8), in a simple one-pot process consisting of the reduction of the carbonyl group by sodium dithionite followed by the substitution with solubility inducing groups under phase transfer catalysis conditions.

View Article and Find Full Text PDF

Scanning tunneling microscopy was used to study the effect of the electron-accepting unit and the alkyl substituent's position on the type and extent of 2D supramolecular organization of penta-ring donor-acceptor-donor (DAD) semiconductors, consisting of either tetrazine or thiadiazole central acceptor ring symmetrically attached to two bithienyl groups. Microscopic observations of monomolecular layers on HOPG of four alkyl derivatives of the studied adsorbates indicate significant differences in their 2D organizations. Ordered monolayers of thiadiazole derivatives are relatively loose and, independent of the position of alkyl substituents, characterized by large intermolecular separation of acceptor units in the adjacent molecules located in the face-to-face configuration.

View Article and Find Full Text PDF

We report large induction (>65(fold) increases) of volatile organic compounds (VOCs) emitted from a single leaf of the invasive weed mossy sorrel, Rumex confertus Willd. (Polygonaceae), by herbivory of the dock leaf beetle, Gastrophysa polygoni L. (Coleoptera: Chrysomelidae).

View Article and Find Full Text PDF

Fusarium infection of maize leaves and/or roots through the soil can stimulate the emission of volatile organic compounds (VOCs). It is also well known that VOC emission from maize plants can repel or attract pests. In our experiments, we studied VOC induction responses of Zea mays L.

View Article and Find Full Text PDF

Role-differentiated bimanual manipulation (RDBM) is a complementary movement of both hands that requires differentiation between actions of the hands. Previous research showed that RDBM can be observed in infants as early as 7 months. However, RDBM could be considered a skill only when its frequency, duration, and use is appropriate for the type of manual task, and there is some evidence of intentionality in use.

View Article and Find Full Text PDF

Background: Defibrotide is a novel orally bioavailable polydisperse oligonucleotide with anti-thrombotic and anti-adhesive effects. In SCID/NOD mice, defibrotide showed activity in human myeloma xenografts. This phase I/II study was conducted to identify the most appropriate dose of defibrotide in combination with melphalan, prednisone and thalidomide in patients with relapsed and relapsed/refractory multiple myeloma, and to determine its safety and tolerability as part of this regimen.

View Article and Find Full Text PDF

Expression of multiple object management skills (manual acquisition and storage of objects) was examined longitudinally at 7, 9, 11, and 13 months for 38 infants (19 females) whose hand use preference was either stable (consistently right or left across the ages) or nonstable (either no hand-use preference exhibited or inconsistent preference across the ages). Four separate sets of four distinctive objects each were presented singly to the infant's right and left side, with the presentation of each subsequent object contingent on the infant manipulating the previous object. Expression of multiple object management skills significantly increased with age.

View Article and Find Full Text PDF

Normal subjects aged 7-25 years were asked to tap the index fingers of both hands: a) in four different patterns of interlimb coordination; b) at two different response frequencies; and c) both before and after the entraining metronome was turned off. The outcome variables of primary interest were the within-subject variability of interresponse intervals (IRI) as an index of timing precision; and deviations from prescribed response frequency, as an index of temporal tracking accuracy. Stability of timing precision and accuracy of temporal tracking increased significantly from 7 to 9 and from 9 to 11 years, with only minor advances thereafter.

View Article and Find Full Text PDF

The major trends in current research on developmental dyslexia assume that impaired phonological processing is the core deficit in this disorder. Our earlier studies indicated that half of all dyslexic persons have significant deficits of bimanual motor coordination, and that impaired temporal resolution in motor action may identify a vertically transmitted behavioral phenotype in familial dyslexia. This report examines the relationship between spelling errors as a measure of impaired phonological processing and motor coordination deficits in the same dyslexia families.

View Article and Find Full Text PDF