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EN
The paper discusses preparation and characteristics of silica hydrophobic layers deposited on the plasma-modified glass supports. The surfaces were investigated using wettability measurements, profilometry, photoacoustic and infrared spectroscopy, X-ray photoelectron spectroscopy as well as scanning electron microscopy. The wettability measurements showed that the obtained surfaces are hydrophobic – the water contact angle was in the range of 140-150 degrees. The photoacoustic and infrared spectroscopy as well as X-ray photoelectron spectroscopy disclosed the surface compositions, particularly that of the hydrophobic alkyl groups deposited on them. They were methyl groups introduced during hydrophobization by hexamethyldisilazane. In addition, it was found that the number of groups on the surface depends on the kind of plasma by which the supports were activated. The optical profilometer showed differences in the surface roughness which affects their hydrophobicity. Moreover, the surface free energies were determined using the contact angle hysteresis method. They disclosed differences in each surface, depending on the way of supports activation. The largest hydrophobicity was obtained on the layer deposited on the support activated by the argon plasma. However, support activation by the air plasma resulted in a decrease of hydrophobicity compared to that of the non-activated surface.
EN
Flotation tests of different size fractions of NaCl, KCl and KPF6   in their saturated aqueous solutions were performed in a 36 cm in height monobubble Hallimond tube. Also contact angle tests by means of sessile drops of saturated salt solution put on pressed discs of salts were carried out. The obtained sessile drop contact angles were equal to zero, pointing to a complete hydrophilicity (orthophilicity) of the investigated salts. In the case of NaCl and KCl, their orthohydrophilicity was confirmed by flotation tests and flotometric considerations because the entrainment factors, which take into account the maximum size of entrained particles and density of the salt as well as it solution, were similar to those of quartz and magnetite and equal to 0.11 mm. The entrainment factor for KPF6  was equal to 0.18 mm and was greater than that of NaCl and KCl indicating certain natural flotation of this salt caused by some flotational hydrophobicity called in this paper metahydrophobicity. The metahydrophobicity of KPF6   was confirmed by flotation results. In the case of KPF6   the maximum yields of the same size particles were the highest, even though the density of this salt was greater than that of NaCl and KCl. Also, the first order kinetic constants were always the greatest for KPF6. Further flotometeric calculation based on the balance of forces involved in flotation indicated that the estimated contact angle of KPF6   was about 8 º   assuming static flotation, and 7 º   for dynamic flotation, while for NaCl and KCl was below 5 º . It means that during flotation test orthohydrophilic NaCl and KCl are only entrained while for metahydrophobic KPF6   there is mostly entrainment and some flotation.
EN
The relationship between electrochemical oxidation (Chronoamperometry) of galena surfaces and collocterless galena flotation was investigated in detail. The chronoamperometry (CA) micro- flotation experiments and zeta potential experiments were performed with ground galena particles (106×53 μm). In addition, contact angle measurements were carried out with a freshly cleaved galena sample at pH 4 in order to investigate any changes in galena surface hydrophobicity after the surface oxidation electrochemically. The results from this study indicated that there is a strong link between the nano/micro-physico-chemical properties of a sulphide on galena surfaces and collectorless flotation of galena particles at pH 4. The results were also supported with the electrokinetics behavior and contact angle values of galena particles.
EN
Effects of In, Ge, Fe substitution in the lattice of sphalerite on wettability were usually ignored, therefore the optimal flotation condition could be difficult to find due to lacking of sufficient theoretical study on water adsorption, resulting lower recoveries of different sphalerites. Adsorption of H2O on different sphalerite surfaces was studied using density functional theory (DFT) method. All computational models were built in a vacuum environment to eliminate the effects of oxygen and other factors. H2O molecule prefers to stay with ideal sphalerite, indium-beard sphalerite, germanium-beard sphalerite and marmatite surfaces rather than water. Compared with ideal sphalerite surface, Fe atom improves the hydrophilicity of surface, while In and Ge atoms reduce the hydrophilicity.
EN
For optimization of diamond processing technology the influence of nanosecond high voltage pulses on mechanical and technological properties of diamond crystals and kimberlite rock-forming minerals (calcite, olivine, serpentine) was investigated. Using methods of Fourier Transform Infrared Spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), microscopy and mikrohardness measurement the changes of structural, physic-chemical surface properties, and microhardness of minerals as the result of impacts, was studied. Non-thermal impacts caused a decrease of kimberlite rock-forming minerals microhardness in general to 40–66% as the result of surface microstructure destruction which is caused by formation of micro cracks, traces of surface breakdown and other defects. At the same time, the pulse energy impact on natural diamonds led to formation of B2 type crystal lattice microsift defects, elevated concentration of which increases the hardness properties of crystals. The obtained result indicates possibility of applying pulsed energy effects to improve the softening efficiency of diamond-bearing kimberlites rock-forming minerals without damaging the diamond crystals and ensuring their preservation by the subsequent grinding of ores. The effect of increasing the natural diamonds flotation activity by 14% (from 47% to 61%) was experimentally established as a result of processing diamond crystals with nanosecond pulses (~ 10–50 sec), which indicates the principal possibility of using pulsed energy impacts to intensify the diamond flotation during processing diamond-bearing kimberlites.
PL
W celu optymalizacji technologii przeróbki diamentów zbadano wpływ impulsów wysokiego napięcia nanosekundowego na właściwości mechaniczne i technologiczne kryształów diamentu i minerałów tworzących skały kimberlitowe (kalcyt, oliwin, serpentynit). Przy pomocy metod spektroskopii w podczerwieni z transformacją Fouriera (FTIR), rentgenowskiej spektroskopii fotoelektronowej (XPS), mikroskopii i pomiaru mikrotwardości badano zmiany strukturalnych, fizykochemicznych właściwości powierzchni oraz mikrotwardości minerałów w wyniku uderzeń. Uderzenia nietermiczne spowodowały zmniejszenie mikrotwardości minerałów tworzących skały kimberlitowe ogólnie do 40–66% w wyniku zniszczenia mikrostruktury powierzchni, spowodowanego powstawaniem mikropęknięć, śladów rozpadu powierzchni i innych wad. Jednocześnie wpływ energii impulsu na naturalne diamenty doprowadził do powstania defektów mikroprzesunięcia sieci krystalicznej typu B2, których podwyższone stężenie zwiększa właściwości twardości kryształów. Uzyskany wynik wskazuje na możliwość zastosowania efektów pulsacji energii w celu poprawy wydajności zmiękczania zawierających diamenty minerałów tworzących skały jak kimberlity, bez uszkadzania kryształów diamentu i zapewnienia ich zachowania w czasie późniejszego mielenia rudy. Efekt zwiększenia naturalnej aktywności flotacyjnej diamentów o 14% (z 47 do 61%) ustalono eksperymentalnie w wyniku przetwarzania kryształów diamentu za pomocą impulsów nanosekundowych (~ 10–50 sekund), co wskazuje na główną możliwość wykorzystania energii pulsacyjnej. Impulsy wpływają na intensyfikację flotacji diamentów podczas przetwarzania kimberlitów zawierających diamenty.
EN
The structural transition from the globular to the amyloid form of proteins requires aggregation-promoting conditions. The protein example of this category is acylphosphatase from the hyperthermophile Sulfolobus solfataricus. This protein represents a structure with a well-defined hydrophobic core. This is why the complexation (including oligomerization) of this protein is of low probability. The chain fragment participating in aggregation in comparison to the status with respect to the fuzzy oil drop model is discussed in this paper.
EN
In this study, the micro-FTIR analysis was used to investigate in-situ surface properties of coal, and was directly correlated to coal hydrophobicity, as measured by the contact angle before and after the addition of collectors, to understand their suitability for flotation. Three different collectors, diesel, pine needle oil and dodecyl trimethyl ammonium bromide (DTAB) were tested. The micro-FTIR technique provided a semi-quantitative analysis of functional groups present on the coal surface exactly where the contact angle was measured and provided a visualization of collector adsorption on specific areas of coal and associated changes in coal surface properties. This analysis could lead to a smarter way of using process design in terms of reagent selection for coal flotation to obtain a product of desired petrographic composition, which would especially be useful for coking coals. This study presents a work in progress for developing a procedure for a quick pre-selection of collectors for coal flotation based on coal surface properties.
PL
Metodą anodowego utleniania stali nierdzewnej i późniejszego nakładania warstw węglowych w procesach CVD otrzymano powłoki o właściwościach hydrofobowych i superhydrofobowych. Modyfikowano parametry procesu CVD i otrzymywano różne struktury węglowe, w tym grafenowe. Warstwy charakteryzowano za pomocą widm Ramana oraz mikroskopii SEM. Zwilżalność powierzchni oceniono badając kąt zwilżania. Próbki zawierające warstwy węglowe wykazywały właściwości hydrofobowe, a te zawierające struktury grafenowe charakteryzowały się kątem zwilżania większym niż 150°, co oznacza właściwości superhydrofobowe.
EN
The method of anodic oxidation of stainless steel and the subsequent deposition of carbon layers in the CVD processes resulted in obtaining the coatings with hydrophobic and superhydrophobic properties. The parameters of the CVD process were modified and various carbon structures, including graphene type ones, were obtained. The coatings were characterised by Raman spectra and SEM microscopy. The wettability of the surface was evaluated by investigating a contact angle. The samples containing carbon coatings showed hydrophobic properties, and those containing graphene structures were characterized by the contact angle greater than 150°, which means superhydrophobic properties.
EN
In this paper, flotation performances of low-rank coal were investigated in the 2-ethyl hexanol, DAH (dodecyl amine hydrochloride), and SDS (sodium dodecyl sulfate) solutions, respectively. In order to reduce the heterogeneity and hydrodynamic effects on the hydrophobicity and movement trajectory of low-rank coal particles, respectively, experimental coal samples with low ash content and 0.500–0.250 mm in size fraction were adopted. The XPS result demonstrated that the total silicium and aluminum content of 0.500–0.250 mm size fraction was 1.58%. It was also found that the ash content of the 0.500–0.250 mm size fraction was 1.91%. Therefore, it demonstrated that there were few hydrophilic mineral particles on the coal sample surface. Thus, the heterogeneity effect of hydrophilic mineral particles during sliding process measurements can be ignored. The XPS result also indicated that after the grinding process, the mineral content on the low-rank coal surface was very small, which would play a small role in the hydrophobicity of low-rank coal samples. The flotation results indicated that the hydrophobicity of the low-rank coal particles could be improved by nonionic 2-ethyl hexanol and cation DAH surfactants. Moreover, from the analysis of slip angle velocity, it demonstrated that the flotation responses of low-rank coal were depressed by anionic SDS. Furthermore, it was observed that the slip angle velocity can be used to evaluate the effect of surfactant agents on the flotation performance of low-rank coal while the surfactant concentration was more than 10–6 mol/L.
PL
W niniejszym artykule zbadano właściwości flotacyjne węgla niskiej jakości w roztworach 2-etyloheksanolu, DAH (chlorowodorku dodecylu) i SDS (dodecylosiarczanu sodu). W celu zmniejszenia niejednorodności i skutków hydrodynamicznych hydrofobowości i trajektorii ruchu cząstek węgla niskiej jakości przyjęto do doświadczeń próbki węgla o niskiej zawartości popiołu z klasy ziarnowej 0,500–0,250 mm. Wynik XPS wykazał, że całkowita zawartość krzemu i glinu w klasie ziarnowej 0,500–0,250 mm wynosiła 1,58%. Stwierdzono również, że zawartość popiołu w klasie ziarnowej 0,500–0,250 mm wynosiła 1,91%. W związku z tym wykazano, że na powierzchni próbki węgla znajduje się niewiele hydrofilowych cząstek mineralnych. W ten sposób można pominąć efekt heterogeniczności hydrofilowych cząstek mineralnych podczas pomiarów kąta poślizgu. Wynik XPS wskazał również, że po procesie mielenia zawartość minerałów na powierzchni węgla niskiej jakości była bardzo mała, dlatego też występuje słabe oddziaływanie na hydrofobowość tych próbek. Wyniki flotacji wskazują, że hydrofobowość cząstek węgla niskiej jakości można poprawić za pomocą niejonowego 2-etyloheksanolu i kationowych środków powierzchniowo czynnych DAH. Analiza prędkości kąta poślizgu wykazuje, że flotacja węgla niskiej jakości została obniżona przez SDS. Ponadto zaobserwowano, że prędkość kąta poślizgu może być wykorzystana do oceny wpływu środków powierzchniowo czynnych na sprawność flotacji węgla niskiej jakości, gdy ich stężenie jest większe niż 10–6 mol/L.
EN
The structure of amyloid Aβ(1-41) is the object of many papers due to the neurodegenerative processes induced by this amyloid. One of the ways to investigate the possible structural forms other than the amyloid is to incorporate the fragment of this peptide into the chain of immunoglobulin. Fragment Aβ(18-41) presented within the CDR3 loop region of a shark immunoglobulin new antigen receptor single-variable domain antibody is the object of this analysis. The structure of this hybrid is available in the PDB and analyzed based on the fuzzy oil drop model. The aim is to define the status of this fragment, revealing the possible fitting to the ordered form of the hydrophobic core. Simultaneously, the verification of the predisposition to complexation is possible.
EN
Polytetrafluoroethylene (PTFE) coatings were manufactured using the pulsed electron beam deposition (PED) technique. The presence of a PTFE structure was confirmed by means of Fourier transform infrared spectrometry (FT-IR). The surface morphology and roughness were characterized by atomic force microscopy (AFM). A pressure increase leads to a decrease in the material transport from the target to the substrate. The water contact angle (WCA) and surface free energy (SFE) were examined. The hydrophobic properties were preserved after film deposition.
PL
Cienkie powłoki z politetrafluoroetylenu (PTFE) wytwarzano metodą pulsacyjnej ablacji elektronowej (PED) z zastosowaniem zmiennego ciśnienia gazu roboczego. Techniką spektroskopii w podczerwieni z transformacją Fouriera (FT-IR) potwierdzono strukturę chemiczną osadzonej cienkiej warstwy. Za pomocą mikroskopii sił atomowych (AFM) oceniano morfologię i chropowatość otrzymanej powierzchni. Wyznaczono kąt zwilżania (WCA) i swobodną energię powierzchniową (SFE) powłok z PTFE. Stwierdzono, że zachowują one hydrofobowe właściwości politetrafluoroetylenu. Zwiększenie wartości zastosowanego w procesie ciśnienia wpłynęło na zmniejszenie grubości osadzanej warstwy PTFE w wyniku pogorszenia transportu materiału z targetu (tarczy) do podłoża.
EN
This study was performed to determine the effect of tannic acid (TA) on hydrophobicity of galena using Taguchi’s design of experimental methodology. Roles of metal ions, dithiophosphinate (DTPI) concentration, and conditioning time on TA-galena interaction were tested by contact angle measurements. Results were evaluated by analysis of variance (ANOVA) test. DTPI was found to be the most effective parameter on the hydrophobicity followed by TA and nobility of metal ions. Effect of conditioning time was statistically insignificant. Electrochemical activity of metal ions became effective on TA-galena interaction: more active metals exhibit synergic effect with TA on the hydrophilicity of galena whereas more noble metals reduced the adverse impact of TA. Taguchi’s design revealed that interactions between experimental variables were not statistically significant.
EN
The influence of synergistic effect between dodecylamine (DDA) and sodium oleate (NaOl) on the hydrophobicity of fluorapatite (FA) was investigated with contact angle, surface tension, XPS and zeta potential studies. The role of pH and the mixing ratio of surfactants on the synergistic behavior were considered. Basing on the contact angle results the suitable pH for the NaOl-DDA mixture was pH 9.5. A further study indicated that the 3:7 DDA-NaOl mixtures could notably improve the contact angle comparing to that only with DDA or NaOl. In the solution of this mixture, the DDA cation and DDA molecule both adsorb at the FA surface as revealed by the XPS spectra results. The zeta potential analysis further suggested that the adsorption of oleate at the FA surface was also improved. The presence of DDA cation and DDA molecule was expected to result in a uniform packing of surfactants at the FA surface.
EN
A fluorine-containing acrylate copolymer emulsion was prepared in this study, which was applied to finishing linen fabric. Dodecafluloroheptry methacrylate (G04) was used as a modified monomer, butylacrylate (BA) and methylacrylate (MMA) as soft and hard monomers.respectively, and acrylic acid as a functional monomer. Structure and properties of the products were characterised and analyzed by FTIR, TEM, PSD and CA measurements, respectively. The water and air permeability as well as the breaking force of the fabric treated were also investigated. The results showed that the fluorine-containing acrylate copolymer emulsion obtained had a core-shell structure, and the microsphere was of nanoscale size. Because of the latex film on the fabric surface, it became smooth and flat. And the increase in G04 was beneficial to the mechanical properties, waterproofness and antifouling ability of the linen fabric. When the content of G04 were increased from 0% to 20%, the water in the linen sample and hexadecane contact angles to the copolymer film increased from 113.02° to 136.08° and from 65.1° to 87.6°,respectively. Furthermore the breaking force of the linen samples was enhanced from 648 N to 721N. However, the increasing content of G04 had negative effects on the flexural rigidity as well as water and air permeability of the fabric, which were essential requirements for the fabric’s application. However, the wash resistance was excellent and the wear-resistance of the finished linen fabric was better than the unfinished linen fabric.
PL
W pracy przygotowano emulsję kopolimeru akrylanowego zawierającą fluor, którą następnie zastosowano do wykańczania tkanin lnianych. Jako modyfikowany monomer zastosowano metakrylan dodekafluoroheptan (G04), a jako miękkie i twarde monomery użyto akrylan butylu (BA) i akrylan metylu (MMA), a kwas akrylowy jako monomer funkcjonalny. Strukturę i właściwości produktów scharakteryzowano i przeanalizowano za pomocą pomiarów FTIR, TEM, PSD i CA. Przebadano również przepuszczalność wody i powietrza oraz siłę zrywania tkaniny poddanej obróbce. Wyniki wykazały, że otrzymana fluorowa emulsja kopolimeru akrylanowego miała strukturę rdzeń-otoczka, a mikrosfera miała rozmiar w nanometrach. Ze lateksowej powłoce tkanina stała się gładka i matowa. Stwierdzono, że wzrost G04 wpływa korzystnie na właściwości mechaniczne, wodoodporność i zdolność przeciwporostową tkaniny lnianej. Zwiększenie zawartości G04 spowodowało wzrost kąta zwilżania, a siła zrywania próbek zwiększyła się z 648 do 721 N. Jednak wzrastająca zawartość G04 miała negatywny wpływ na sztywność zginania, a także przepuszczalność wody i powietrza tkaniny, które były zasadniczymi cechami wymaganymi dla aplikacji tkaniny. Jednakże odporność na pranie i zużycie była lepsza w przypadku próbek powleczonych.
15
Content available remote Structure of hydrophobic core in plant carboxylesterase
EN
The fuzzy oil drop model was applied to characterize the hydrophobic core structure in plant carboxylesterase. The characteristics revealed the status of β-sheets in the central part of the molecule as discordant as opposed to the expected hydrophobicity distribution. Particularly, the β-strands and helices in close proximity to the enzymatic residues recognized as discordant with respect to the ideal hydrophobicity distribution of hydrophobic core are of high importance. It is assumed that this local irregularity is the form of coding the specificity of enzymes. The protein under consideration appears to be the next example proving this assumption.
16
EN
Cardiac myosin binding protein C is the object of analysis presented in this paper. The fuzzy oil drop model was applied to analyze the status of the hydrophobic core in two forms of this protein: WT and R502W mutant. The status of the mutant is revealed to be of lower stability than the WT form. The high order of the hydrophobic core is interpreted as the factor of stability of the tertiary structure. The muscle proteins, which undergo significant structural changes as the consequence of external stretching forces, are expected to return to initial structures after the release of an external force. The mutant R502W appears to represent lower stability; thus, the return to the initial structure may be of lower probability. The comparable analysis to other muscle domains (titin) and immunoglobulin domains suggests the very subtle relation to the biological activity of these proteins.
17
Content available remote Mechanism of ligand binding – PDZ domain taken as example
EN
Abstract: The mechanism of specific ligand binding by proteins is discussed using the PDZ domain complexing the pentapeptide. This process is critical for clustering the membrane ion channel. The traditional model based on the Beta-sheet extension by complexed pentapeptide is interpreted as a hydrophobic core extension supported by additional Beta-strand generated by complexed pentapeptide. The explanation is based on the fuzzy oil drop model applied to the crystal structure of PDZ-pentapeptide.
EN
Heme binding by proteins and protein-protein complexation are the processes strongly related to the biological activity of proteins. The mechanism of these processes has not been still recognised. These phenomena are presented using haemoglobin as the example. Half of the mature haemoglobin (one α-chain and one β-chain) treated as a dissociation step in haemoglobin degradation reveals a specific change in heme binding after dissociation. This phenomenon is the object of analysis that interprets the structure of both complexes (tetramer and dimer) with respect to their hydrophobic core structure. The results suggest the higher stability of the complex in the form of one α-chain and one β-chain with respect to the hydrophobic core.
EN
The work presents investigation on the water droplet impingement at a substrate with three different surface coating. The experiments are carried out for two temperatures of the surface: 23 degrees centigrade (room temperature) and 10 degrees centigrade. The water droplet contact is recorded via ultra-fast camera and simultaneously via fast thermographic camera. The wetting properties are changing for subzero temperatures of substrates.
20
Content available remote Structural similarity of CheY-like proteins
EN
The problem of structural similarity of polypeptide chains of low sequence similarity representing a similar 3D structural form has been the object of analysis of researchers engaged in the protein folding problem. Three homologous proteins of similar biological function with low sequence similarity are the objects of analysis presented in this paper. The structure of a hydrophobic core is used as the criterion for structural similarity assessment of these three proteins. The applied method allows recognition of differentiati on in topologically similar structures.
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