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Analiza prawnych regulacji działalności gospodarczej w zakresie krajowego transportu drogowego

Pieniak A., Niewczas A., Dmowski A.

Autobusy : technika, eksploatacja, systemy transportowe

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2010

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R. 11, nr 6

PL

W artykule zaprezentowano aktualny stan prawny regulujący zasady podejmowania i wykonywania transportu drogowego osób i rzeczy na terytorium Rzeczypospolitej Polskiej. Przedstawiono wymagania jakie muszą spełniać przewoźnicy oraz pośrednicy, aby wykonywać działalność gospodarczą w zakresie transportu drogowego. Ponadto przedstawiono analizę wybranej formy reglamentacji krajowego transportu drogowego. Szczegółowo opisano postanowienia ustawy z dnia 6 września 2001 roku o transporcie drogowym, a w szczególności przepisy określające zakres i warunki udzielania licencji na krajowy transport drogowy. Następnie przedstawiono regulacje prawne dotyczące odmowy udzielenia, zmiany lub cofnięcia licencji w zakresie transportu drogowego, oraz opłat za czynności administracyjne związane z wykonywaniem transportu drogowego.

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Application of thin-layer chromatography (TLC) to investigating oscillatory instability of the selected profen enantiomers

Sajewicz M., Piętka R., Pieniak A., Kowalska T.

Acta Chromatographica

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2005

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No. 15

131-149

EN

In our earlier studies we intended to evaluate the performance of thin-layer chromatography (TLC) as an analytical tool applied to separation of the selected profen (i.e. 2-arylpropionic acid) enantiomers and we se-lected ibuprofen as a model analyte for this purpose. Surprisingly enough, TLC is relatively seldom used for separation of enantiomers, even though – despite the low number of theoretical plates (N) in this particular techni-que in comparison with fully automated column chromatographic techni-ques (basically GC and HPLC) – it seems very well suited for complete separation of two analytes only (i.e. a pair of enantiomers). Separation of profens can be regarded as a particularly urgent ana-lytical task, because they are among the most widely prescribed synthetic non-steroidal anti-inflammatory drugs and in medicinal chemistry we must be vigilantly aware of possible unpredictable consequences of dispensing medicines as racemic mixtures. In earlier and in more recent studies we have provided enough evi-dence not only to prove that the analytical performance of TLC is suffi-cient for separation of the enantiomers of ibuprofen, but also – even more important – to demonstrate the usefulness of this simple yet very efficient separation technique in physicochemical studies of the oscillatory instability of profens when stored for long periods of time in aqueous media. By use of TLC it was possible to show the oscillatory transenantiomerization of the profens from the S to the R form, and vice versa, during storage. The correctness of our TLC assessment with regard to structural oscillation of enantiomeric profens was later successfully confirmed by means of pola-riemetry.

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Densitometric acquisition of concentration profiles in planar chromatography and its possible shortcomings. Part 1. 4-phenylbutyric acid as analyte

Sajewicz M., Pieniak A., Piętka R., Kaczmarski K., Kowalska T.

Acta Chromatographica

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2004

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No. 14

5-15

EN

In this paper we describe part of a study originally devoted to inve-stigating lateral interactions of 4-phenylbutyric acid in 'mild' chromatogra-phic systems comprising low-activity stationary phases (microcrystalline cellulose or chromatography paper) and low-polarity decalin as mobile phase. The presence or absence of lateral interactions of an analyte in a given chromatographic system can be judged from the shape of the concentration profile and for this purpose densitograms of the bands of interest must first be acquired. Our attention was unexpectedly attracted by a largely surprising observation that the concentration profile of 4-phe-nylbutyric acid on cellulose powder could be measured easily on a freshly developed chromatogram only after drying whereas on chromatography paper developed at room temperature it was hardly detectable, and became fully shaped only two days later. To explain this striking phenomenon we had to perform several additional experiments and, although the final answer is not fully conclusive, a tentative explanation can already be presented.

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A densitometric study of co-elution in thin-layer chromatography, and its physicochemical modeling

Pieniak A., Kaczmarski K., Sajewicz M., Zapała W., Gołębiowska A., Tomala R., Kowalska T.

Acta Chromatographica

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2004

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No. 14

16-36

EN

In our earlier efforts to scrutinize lateral interactions among test analyte molecules, and their impact on the shape of the respective concen-tration profiles of thin-layer chromatographic bands, we focused our atten-tion on single analytes able to self-associate by hydrogen bonding of their functional groups (and primarily on alcohols and carboxylic acids). Distinct demonstration of lateral interactions is possible only when the analyte is applied to a stationary phase in an amount within the non-linear region of its adsorption isotherm. One must, moreover, ensure the chromatographic conditions are relatively mild, i.e. a low-activity adsorbent used as statio-nary phase and a low-polarity mobile phase. Such conditions guarantee that lateral interactions among the analyte molecules are to a large extent unaffected and therefore observable by densitometry. In the TLC study reported in this paper we focused on co-elution of a binary mixture of test analytes. For the purpose of our experiment we chose two such mixtures: (i) a carboxylic acid (2-phenylbutyric acid, which is, simultaneously, a Lewis acid and a Lewis base (AB)) and a ketone (benzophenone, which is a Lewis base (B) only); and (ii) an aliphatic alco-hol (5-phenylpentanol, which is, simultaneously, a Lewis acid and Lewis base (AB)) and the same ketone (i.e. benzophenone). Because of their fun-ctionality, these two pairs of compounds can form mixed associative struc-tures by hydrogen bonding. It is worthy of note that the retention (i.e. RF values) of each of the two analytes from a given pair is perceptibly different if each is chromatographed as a single species. Using mild chromatographic conditions and working in the non-linear region of the adsorption isotherm we managed to (i) demonstrate co-elution of the two analytes from each pair in the form of a single chromatographic band; (ii) suggest (optional or complementary) three different physicochemical explanations of their den-sitometrically measured concentration profiles; and (iii) perform semi-quantitative simulations of these profiles. Most of the results discussed were obtained by planar chromato-graphy (TLC) but some experiments were repeated with a column-chro-matographic technique, HPLC, using fully analogous working conditions (i.e. low-activity carbohydrate stationary phase and low-polarity hydrocar-bon mobile phase). Some of the results obtained by HPLC were similar to those from planar chromatography whereas others were dissimilar.