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Extracellular vesicles (EVs) are cell-derived, membrane-enclosed particles with the potential for a wide range of future therapeutic applications. However, EVs have almost always been administered by direct injection, likely hindering their efficacy because of rapid clearance from the injection site. The present study aimed to incorporate medium-sized extracellular vesicles (mEVs) into fast-dissolving electrospun polyvinylpyrrolidone-based nanofibers to explore the storage-dependent structure–activity relationship of the resulting nanofibrous formulations. Aqueous polyvinylpyrrolidone-based precursor solutions were selected for the electrospinning process. The presence of EVs in the electrospun samples was confirmed by transmission electron microscopy, flow cytometry, and confocal laser scanning microscope. The results indicate that the fibrous structure of the samples was preserved until the end of the 12-week storage period. Furthermore, regardless of the storage temperature (4 °C or room temperature), nanofibers and nanofiber-associated EVs were present throughout the experimental period. Incorporating EVs into a stable solid polymeric delivery base could preserve their stability; meanwhile, according to the characteristics of the polymer, their targeted and controlled release can be achieved.

Preventing infectious diseases has become particularly relevant in the past few years. Therefore, antiseptics that are harmless and insusceptible to microbial resistance mechanisms are desired in medicine and public health. In our recent work, a poly(ethylene oxide)-based nanofibrous mat loaded with sodium chlorite was formulated.We tested the chlorine dioxide production and bacterial inactivation of the fibers in a medium, modeling the parameters of human exhaled air (ca. 5% (Smooth-surfaced, nanoscale fibers were produced. The ClOChlorine dioxide was liberated into the gas phase in the presence of CO

Enzyme replacement therapies (ERT) have been of great help over the past 30 years in the treatment of various lysosomal storage disorders, including chronic pancreatitis and its common complication, exocrine pancreatic insufficiency. Research shows that difficulties in designing such drugs can be overcome by using appropriate additives and various enzyme immobilization techniques. Cyclodextrins (CDs) can be considered as a promising additive for enzyme replacement therapies, as they are known to enhance the activity of enzymes in a complex process due to their specific binding. In this study, we investigated the formulation of lipases (from Aspergillus oryzae and Burkholderia cepacia) paired with different cyclodextrins in poly(vinyl alcohol) (PVA) nanofibers by electrospinning technique. We examined the effect of the presence of cyclodextrins and nanoformulation on the lipase activity. The rheological and morphological characterizations of precursors and nanofibers were also performed using a viscometer as well as electron and Raman microscope. We found that by selecting the appropriate CD:lipase ratio, the activity of the investigated enzyme could be multiplied, and cyclodextrins can support the homogeneous dispersion of lipases inside the solid formula. In addition, the entrapment of lipases in PVA nanofibers led to a significant increase in activity compared to the preformulated precursor. In this way, the nanofibrous formulation of lipases combining CDs as additives can provide an efficient and sustainable possibility for designing novel solid medicines in ERT.

Several applications of nanofiber-based systems are based on their corresponding functionality-related properties, which often cannot be satisfied by a fiber web with a monolithic structure because of the various physicochemical properties and amounts of embedded compounds. Therefore, one of the main directions in the development of fiber systems is creating core–shell type complex fiber structures that can provide application-specific properties to the fiber matrix. The present study aimed to formulate levocetirizine-loaded core–shell type hydrophilic polymer-based fibrous systems. The core phase contained the antihistamine levocetirizine, while the permeation enhancer (Na-taurocholate), the local pH regulator (citric acid), and the cyclodextrin used as a taste masking agent were included in the shell phase of the fibrous formulation. Scanning electron microscopy images indicated that a randomly oriented homogeneous fibrous structure was obtained, while the Raman mapping and chemometric analysis confirmed the partially formed core–shell structure. A fast release rate of the antihistamine drug from the complex structural fibrous system was obtained (within 1 min complete dissolution can be observed) due to its increased surface area to volume ratio and its more favorable wettability properties, which consequently allows for more erosion. The masking properties against the unpleasant bitter taste of API of the formulated complex nanostructure were confirmed by the results of the electronic tongue. The formulated complex nanostructure enabled fast and complete release of the API, providing a potential enhancement in the rate and extent of absorption while masking the unpleasant taste of levocetirizine, which has a high impact on the patient adherence. All in all, the results show that the developed orally dissolving fibrous web formulation can be a potential alternative to the commercially available orally disintegrating tablets.

As a result of the nationally and internationally expected rapidly increasing photovoltaic penetration,the structure of the electric power system is becoming increasingly decentralized, and resulting inpower stability questions and problems that can beanswered by running stochastic simulations of thenetwork (reference networks). In this paper, a reference network formulation methodology (principalcomponent analysis with 95% coverage, the determination of optimal cluster number – 6, and K-meansclustering) on a large scale medium voltage network,characterized by mathematical and physical parameters is presented &nbsp

Nowadays the electricity consumption is increasingly covered by green energy, generated by photovoltaic systems. This tendency is becoming morewidespread among residential consumers. Theseconsumers should be examined in groups, in energycommunities. In the case of such consumers, it canbe stated that between the photovoltaic productionand consumption the simultaneity is relative low,thus significantly affecting the operation of the electricity distribution system. In the case of using energy storage device, the simultaneity values increasesignificantly (cannot be assessed below a 30% penetration level). The simultaneity enhancing effect ofthe examined LiFePO4 battery prevails better with increasing penetration. Looking at the financial payback on the investment, it can be said that at currentprices it will not pay back during the predicted lifetime of the battery (10 years). &nbsp

Nowadays, in electricity generation, renewable energy sources tend to play a more and more significant role. From these entities photovoltaic (PV) systems have the most noticeable penetration in Hungary. During operation both on the module- and onthe inverter side degradation appears, which has adecreasing impact on electricity production. In thispaper temporal changes of system lifetime weremodelled by a linear degradation model specified toHungary. Moreover, a maintenance case study of apower plant with 498 kVA output power is presented.In context of return an optimal maintenance scheduleis presented. Regarding the implied investment financial return was determined, based on the exchange rate of electricity. Finally, this paper concludes that in case of inverters the replacement is refunded during their life cycle but not profitable forphotovoltaic modules. &nbsp

In recent years, core-shell nanofibrous drug delivery systems have received increasing attention due to their ability to incorporate two or more active pharmaceutical ingredients (APIs) individually into the desired layer (either core or sheath) and thereby finely tune the release profiles of even incompatible drugs in one system. This study aims to perform formulation and solid-state characterisation of levofloxacin-loaded polylactic acid (PLA) - naproxen-sodium-loaded polyvinyl pyrrolidone (PVP) bicomponent core-shell fibrous sheets and examine the electro spinnability of the precursor combinations. The selected drugs have potential therapeutic relevance in similar systems intended for wound healing; however, in this study, they are used as model drugs to understand the physicochemical properties of a drug loaded system. In order to determine the best core- and shell-solution combination, a full factorial experimental design is used. A combination of various morphological (scanning electron microscopy and transmission electron microscopy) and microstructural characterisation techniques (X-ray photoelectron spectroscopy and Raman spectroscopy) was applied to non-invasively obtain information about the structure of the fibres and the embedded drugs. The results indicate that core-shell fibres of different compositions could be successfully prepared with various structural homogeneities. The best core-shell structure was obtained using a combination of 15% (w/w) shell concentration and 8% (w/w) PLA solution concentration. In addition to the conventional core-shell structural verification methods, the Raman spectroscopy method was implemented to reveal not only the core-shell structure of the PLA/PVP nanofibers but also the form of the embedded drugs. The Raman mapping of the fibres confirm the above results, and it is shown that an amorphous solid dispersion is formed as a result of the coaxial electrospinning process.

Fenofibrate-loaded electrospun microfibrous sheets were prepared in an attempt to enhance the dissolution of the poorly soluble antihyperlipidemic agent and to improve its bioavailability. Physicochemical changes that appeared during the electrospinning process were monitored using a wide array of solid-state characterization techniques, including attenuated total reflectance Fourier-transformed infrared spectroscopy and positron annihilation lifetime spectroscopy, while fiber morphology was monitored via scanning electron microscopy. Dissolution studies carried out both in 0.025 M sodium dodecyl sulfate and in water revealed an immediate release of the active agent, with an approximately 40-fold release rate enhancement in water when compared to the micronized active agent. The dramatic increase in dissolution was attributed partially to the amorphous form of the originally crystalline active agent and the rapid disintegration of the electrospun microfibrous sheet due to its high surface area and porosity. The obtained results could pave the way for a formulation of the frequently used antihyperlipidemic agent with increased bioavailability.

Electrospun nanofibers were prepared from furosemide-containing hydroxypropyl cellulose and poly(vinylpyrrolidone) aqueous solutions using different solubility enhancers. In one case, a solubilizer, triethanolamine, was applied, while in the other case a pH-modifier, sodium hydroxide, was applied. Scanning electron microscopy (SEM) was carried out for morphological characterization of the fibers. The SEM images indicated similar mean diameter size of the two fibrous formulations. However, in contrast to the NaOH-containing fibers of normal diameter distribution, the triethanolamine-containing fibers showed approximately normal diameter distribution, possibly due to their plasticizing effect and the consequent slightly ribbon-like morphology. Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), powder X-ray diffraction (XRD) and positron annihilation lifetime spectroscopy (PALS) were applied for microstructural characterization. The FTIR measurements confirmed that furosemide salt was formed in both cases. There was no sign of any crystallinity based on the XRD measurements. However, the PALS highlighted the differences in the average o-Ps lifetime values and distributions of the furosemide-loaded fibrous formulations. The two types of electrospun nanofibrous formulations containing amorphous furosemide salt showed similar macrostructures but different microstructural characteristics depending on the type of solubility enhancers, which lead to altered storage stability.

Background: Preventing infectious diseases has become particularly relevant in the past few years. Therefore, antiseptics that are harmless and insusceptible to microbial resistance mechanisms are desired in medicine and public health. In our recent work, a poly(ethylene oxide)-based nanofibrous mat loaded with sodium chlorite was formulated. Methods: We tested the chlorine dioxide production and bacterial inactivation of the fibers in a medium, modeling the parameters of human exhaled air (ca. 5% (v/v) CO2, T = 37 °C, RH > 95%). The morphology and microstructure of the fibers were investigated via scanning electron microscopy and infrared spectroscopy. Results: Smooth-surfaced, nanoscale fibers were produced. The ClO2-producing ability of the fibers decreased from 65.8 ppm/mg to 4.8 ppm/mg with the increase of the sample weight from 1 to 30 mg. The effect of CO2 concentration and exposure time was also evaluated. The antibacterial activity of the fibers was tested in a 24 h experiment. The sodium-chlorite-loaded fibers showed substantial antibacterial activity. Conclusions: Chlorine dioxide was liberated into the gas phase in the presence of CO2 and water vapor, eliminating the bacteria. Sodium-chlorite-loaded nanofibers can be sources of prolonged chlorine dioxide production and subsequent pathogen inactivation in a CO2-rich and humid environment. Based on the results, further evaluation of the possible application of the formulation in face-mask filters as medical devices is encouraged.

Papaverine hydrochloride loaded gels, films and electrospun fibers were prepared for buccal drug delivery with the aim of improving the oral bioavailability of the crystalline drug, which can be achieved by the increased solubility and by the circumvention of the intensive first pass metabolism. The water soluble hydroxypropyl cellulose (HPC) was chosen as a mucoadhesive polymer. In order to improve the electrospinnability of HPC, the similarly mucoadhesive poly(vinyl alcohol) (PVA) was used. Since the drying of gels is of decisive role in either the formation of drug-loaded cast films or electrospun fibers, a real time ortho-positronium (o-Ps) tracking of gels was applied in order to obtain information about the supramolecular changes of the drying-induced gel-film transition. An anomalous increase of o-Ps lifetime value in the gel-film transition region was observed which refers to the remaining intramolecularly bound water in the drug-loaded polymeric gel matrix. The latter could provide information about the characteristics of polymer-water interactions in the phase transition, consequently the storage stability of the formulated solid system.

The electrospun nanofiber-based orally dissolving webs are promising candidates for rapid drug release, which is due to the high surface area to volume ratio of the fibers and the high amorphization efficacy of the fiber formation process. Although the latter is responsible for the physical and/or chemical instability of these systems. The primary aim of the present study was to elucidate how the addition of polysorbate 80 (PS80) and hydroxypropyl-β-cyclodextrin (HP-β-CD) influenced the electrospinning process, the properties, and the behavior of the obtained nanofibers. In order to reveal any subtle changes attributable to the applied excipients, the prepared samples were subjected to several state of the art imaging and solid state characterization techniques at both macroscopic and microscopic levels. Atomic force microscopy (AFM) revealed the viscoelastic nature of the fibrous samples. At relatively low forces mostly elastic deformation was observed, while at higher loads plasticity predominated. The use of polysorbate led to about two times stiffer, less plastic fibers than the addition of cyclodextrin. The

Topically applied antiviral creams and patches are the commercially available options for the treatment of herpes labialis. The nanofibrous patches could be a new direction in the formulation. The project aimed to formulate core-shell type nanofibrous scaffolds loaded with dexpanthenol (shell) and acyclovir (core). To achieve the fast dissolution of the antiviral agent, hydroxypropyl-beta-cyclodextrin was used as a complexation agent. The further aim was to study the prepared electrospun scaffolds' morphological- and physicochemical properties and antiviral activity. The fibrous samples were prepared by electrospinning using polyvinylpyrrolidone (PVP) as a shell, hypromellose (HPMC), and poly(ethylene oxide)(PEO) composite or poly(vinyl alcohol) (PVA) as a core polymer. The morphology of the prepared sample was studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy. The SEM photos showed that fibrous structures were obtained. In the case of the PVA/PVP composition, the desired structure was obtained. While when HPMC-PEO was used as a core, the core-shell structure could not be observed. The Raman measurements revealed the mixed fibre structure of this sample. All of the fibrous samples released about 100% of acyclovir and also the dexpanthenol within 20 min. Coaxially electrospun fibres of different compositions were successfully prepared with various structural homogeneities, furthermore, a better antiviral activity could be achieved compared to the commercially available Zovirax cream. ispartof: INTERNATIONAL JOURNAL OF PHARMACEUTICS vol:611 ispartof: location:Netherlands status: published

Papaverine hydrochloride loaded electrospun fibers were prepared for buccal drug delivery with the aim of improving the oral bioavailability of the crystalline drug, which can be achieved by the increased solubility and by the circumvention of the intensive first pass metabolism. The water soluble hydroxypropyl cellulose (HPC) was chosen as a mucoadhesive polymer. In order to improve the electrospinnability of HPC, the also mucoadhesive poly(vinyl alcohol) (PVA) was used. During the experiments, the total polymer concentration was kept constantly at 15% (w/w), and only the ratio of the two polymers was changed. Five different HPC:PVA ratios (5:5, 6:4, 7:3, 8:2, 9:1) were examined. Combination of rheological measurements and molar reflectance characterization with scanning electron microscopy was applied for the determination of the optimum composition of the gels for fiber formation. The crystalline-amorphous transition of papaverine hydrochloride was also tracked by Fourier transform infrared spectroscopy. A correlation was found between the macrostructural properties of the polymer solutions and their electrospinnability and the consequent morphology of the resultant samples. Along with the changes of the polymer ratio, the corresponding morphology of the electrospun samples also varied. With decreasing HPC ratio of the system, a transition from the spray-dried film-like structure through fibrous film to fibers was observed. Polymer solutions of the lowest elasticity and smallest intermolecular interactions contributed to the best fiber characteristics of the samples. The results enable the determination of the polymer ratio for the formation of applicable quality of electrospun fibers. According to the results 5:5 and 6:4 polymer ratios enabled the best fiber performance.

Aceclofenac-loaded poly(vinyl-pyrrolidone)-based nanofiber formulations were prepared by electrospinning to obtain drug-loaded orally disintegrating webs to enhance the solubility and dissolution rate of the poorly soluble anti-inflammatory active that belongs to the BCS Class-II. Triethanolamine-containing ternary composite of aceclofenac-poly(vinyl-pyrrolidone) nanofibers were formulated to exert the synergistic effect on the drug-dissolution improvement. The composition and the electrospinning parameters were changed to select the fibrous sample of optimum fiber characteristics. To determine the morphology of the nanofibers, scanning electron microscopy was used. Fourier transform infrared spectroscopy (FT-IR), and differential scanning calorimetry (DSC) were applied for the solid-state characterization of the samples, while the drug release profile was followed by the in vitro dissolution test. The nanofibrous formulations had diameters in the range of few hundred nanometers. FT-IR spectra and DSC thermograms indicated the amorphization of aceclofenac, which resulted in a rapid release of the active substance. The characteristics of the selected ternary fiber composition (10 mg/g aceclofenac, 1% w/w triethanolamine, 15% w/w PVPK90) were found to be suitable for obtaining orally dissolving webs of fast dissolution and potential oral absorption.

Nowadays photovoltaic systems can be considered to play the key role in increasing decentralized power generation. These power generation systems are typically connected to distribution networks and affecting their operation. The spread of high output power connection demands the development of the infrastructure. Examination of development opportunities is done with software simulation, so the creation network models are required. To achieve a large-scale simulation, the generation of reference networks which describe real networks well is essential. In order for the reference networks to be created, clustering of real networks may be a solution. When the clusters and their parameters are defined well the software implementable of networks can be created. In this work, the clustering process of Hungarian distribution networks, the determination of the optimal cluster number, and the established network clusters are also presented.

International audience; 3D printing is attracting considerable interest for its capacity to produce prototypes and small production runs rapidly. Fused deposit modeling (FDM) was used to produce polyvalent test plates for investigation of the physical, chemical, and in-vitro biological properties of printed materials. The polyvalent test plates (PVTPs) are poly-lactic acid cylinders, 14 mm in diameter and 3 mm in height. The polymer ester backbone was surface modified by a series of ramified and linear oligoamines to increase its hydrophilicity and introduce a positive charge. The chemical modification was verified by FT-IR spectroscopy, showing the introduction of amide and amine functions, and contact angle measurements confirmed increased hydrophilicity. Morphology studies (SEM, optical microscopy) indicated that the modification of PVTP possessed a planar morphology with small pits. Positron annihilation lifetime spectroscopy demonstrated that the polymeric free volume decreased on modification. An MTT-based prolonged cytotoxicity test using Caco-2 cells showed that the PVTPs are non-toxic at the cellular level. The presence of surface oligoamines on the PVTPs reduced biofilm formation by Candida albicans SC5314 significantly. The results demonstrate that 3D printed objects may be modified at their surface by a simple amidation reaction, resulting in a reduced propensity for biofilm colonization and cellular toxicity

The nano- and micro fibrous systems in the textile- and plastics industry have already been used, although the opportunity for using them as medical devices has only come in recent years into view. Since then in medical sciences they have shown promise in different therapeutic purposes. The manuscript summarizes the opportunities for medical use of the nano- and micro fibrous systems.

The production data of solar systems are well described by their density and distribution function. However, the mathematical description of this empirical curve is not known in closed form. So as to define the distributions, they should be approximated with special distributions. As the incident solar irradiation to the surface of photovoltaic modules can be approached with Beta-distribution, the daily average production, total daily production and the daily maximum values can be reached with that distribution as well. However, to define the parameters of a special mathematical distribution, significant resources are required. A great number of calculation software for engineers can assist the empirical density function to be adjusted by special distributions so that the parameters are displayed as the result of the calculation. Awareness of these parameters can help determine the empirical curve approximation, and the goodness of approximation can be measured with pre-defined error indicators. In this study the electricity production of photovoltaic systems, placed in different parts of Hungary, was examined from different aspects. The approximation of empirical density- and distribution functions, received from the defined aspects, with Beta-distribution has proven to have appropriate accuracy, since the error indicators in most cases were found to have a very low value.

Electrospun papaverine hydrochloride-loaded nanofibrous sheets consist of hydroxypropyl cellulose/poly(vinyl alcohol) composite were prepared for buccal administration for cerebral ischemia. The nanofibrous drug delivery system was subjected to accelerated stability test for four weeks in order to scrutinize the solid state changes relating to the stress induced (40 ± 2 °C/75 ± 5% relative humidity) physical ageing. Micro- and macrostructural alterations were detected using scanning electron microscopy (SEM), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR) and positron annihilation lifetime spectroscopy (PALS). Significant changes were revealed at both supramolecular and macroscopic levels. Microscopic morphology uncovered major morphological transitions. Subtle variations of Raman and FTIR spectra indicated that the local chemical environment of papaverine was altered suggesting a partial phase transition of the active. Discrete o-Ps lifetimes and lifetime-distributions unveiled a two-step ageing process of the drug carrier. In addition to the tracking of the glassy-to-rubbery transition of the fiber forming polymers, the Raman spectroscopy enabled monitoring the kinetics of the phase transition observed.

The complete physico-chemical characterization of the single enantiomer analgesic drug R,R-tapentadol was quantitated in terms of protonation macro- and microconstants and octanol–water partition coefficient using pH-potentiometry, UV-pH and 1H NMR-pH titrations. The protonation macroconstants were found to be log K1 = 10.59 ± 0.01 and log K2 = 9.44 ± 0.01, while the individual basicity of each protonation site was found to be log kO = 9.94 and log kN = 10.48 for the phenolate and tertiary amine functions, respectively. As a consequence, the zwitterionic form of tapentadol predominates in aqueous solutions. The potential optical impurity (S,S-tapentadol) was synthesized for the first time in a seven-step chiral synthetic procedure. The enantiomers of tapentadol were separated by cyclodextrin modified capillary zone electrophoresis. Over 15 cyclodextrins were investigated in terms of apparent complex stability and screened as chiral selectors, and the sulfated alpha-cyclodextrin was found to resolve the enantiomers with excellent resolution (Rs = 16.2 and 9.1) at pH 4.75 and pH 9.0, respectively. The system containing 12 mM selector in a 50 mM TRIS–acetate buffer was amenable to detect S,S-tapentadol potential optical impurity at 0.1% concentration level.

The enantiomers of vildagliptin, an orally available and selective dipeptidyl-peptidase-4 inhibitor used for the treatment of type II diabetes, have been separated by CD-modified CZE, using uncoated fused-silica capillary. After screening 13 negatively charged CD derivatives as potential chiral selectors, sulfobutyl-ether-α-CD (SBE-α-CD) was selected for the enantioseparation. For the optimization, a factorial analysis study was performed by orthogonal experimental design. Six experimental factors were chosen as variable parameters: temperature, applied voltage, chiral selector and BGE concentrations, pH, and the parameters of the hydrodynamic injection. The optimized system still was not considered final as the second peak (S-enantiomer) migrated too close to the EOF, resulting in a potential inaccuracy during the determination of the chiral impurity. To fine-tune the method "one factor at a time" variation approach was applied. The final method (applying 15°C capillary temperature, 40 mbar × 4 s hydrodynamic injection, 25 kV voltage in 75 mM acetate-Tris buffer [pH 4.75] containing 20 mM SBE-α-CD as chiral selector) was validated according to the ICH guideline. RSD percentage of the resolution value, migration times, and corrected peak areas were below 5% during testing repeatability and intermediate precision. LOD and LOQ values were found to be 2.5 and 7.5 μg/mL, respectively. The method is considered linear in the 7.5-180 μg/mL range for the R-enantiomer. The robustness of the method was justified using Plackett-Burmann statistical experimental design.

The single isomer drug R,R -tadalafil (Cialis ® ) contains two chiral centers thus four stereoisomers ( R,R- , S,S- , S,R- and R,S- tadalafil) exist, however, only the most potent inhibitor, the R,R- tadalafil is in clinical use. In our study, over 20 charged cyclodextrin (CD) derivatives were studied for enantiospecific host–guest type interactions in CD-modified capillary electrophoresis. Tadalafil stereoisomers are non-charged; therefore, their electrophoretic separation poses a challenge. Several candidates of both positively and negatively charged hosts were found to be effective for the enantioseparation. Eight out of the beta derivatives and three of alpha derivatives (including sulfated, sulfoalkylated, carboxyalkylated and amino derivatives) resolved all four stereoisomers partially or completely. Cavity size-dependent absolute enantiomer migration order (EMO) reversals were observed in the case of sulfopropyl-alpha (EMO: R,S ; S,R ; R,R ; S,S ) and sulfopropyl-beta ( S,S; R,R; S,R; R,S ) derivatives, while substituent-dependent partial EMO reversals were detected for sulfobutyl-ether-alpha ( R,S; S,R; S,S; R,R ) and sulfated-alpha-CD ( R,R; S,S ; R,S ; S,R ) selectors. Complexation-induced 1 H NMR chemical shift changes reflected that the benzodioxole moiety plays a major role in cavity size-dependent EMO reversal. Sulfobutyl-ether-alpha-CD was the only selector that provided the desired EMO in which the clinically applied eutomer R,R- tadalafil migrates last. Finally, an electrophoretic method applying a background electrolyte (BGE) containing 75 mM Tris–acetic acid buffer (pH 4.75) and 7 mM sulfobutyl-ether-alpha-CD was developed for the baseline resolution of all isomers at 25 °C and +25 kV applied voltage.

Sputtering of Cu and other bcc and fcc metal crystals due to Ar ion bombardment is studied. The results obtained by a computer model using two-body interactions governed by Bohr-type interatomic potential are given. The applicability of the hard sphere collision approximation is also proved, and dependence of the collision cross section on the atomic number of the target crystal is studied by this model.

Preliminary studies on the possibility of eliminating the dangling bonds in a cluster model calculation by connecting the cluster into itself. The calculation was made on a SiO2 cluster, using the CNDO/2 method.