Purification of pharmaceuticals and nutraceutical compounds by sub- and supercritical extraction and chromatography

This thesis discusses the use of sub- and supercritical fluids as the medium in extraction and chromatography. Super- and subcritical extraction was used to separate essential oils from herbal plant Angelica archangelica. The effect of extraction parameters was studied and sensory analyses of the extracts were done by an expert panel. The results of the sensory analyses were compared to the analytically determined contents of the extracts. Sub- and supercritical fluid chromatography (SFC) was used to separate and purify high-value pharmaceuticals. Chiral SFC was used to separate the enantiomers of racemic mixtures of pharmaceutical compounds. Very low (cryogenic) temperatures were applied to substantially enhance the separation efficiency of chiral SFC. The thermodynamic aspects affecting the resolving ability of chiral stationary phases are briefly reviewed. The process production rate which is a key factor in industrial chromatography was optimized by empirical multivariate methods. General linear model was used to optimize the separation of omega-3 fatty acid ethyl esters from esterized fish oil by using reversed-phase SFC. Chiral separation of racemic mixtures of guaifenesin and ferulic acid dimer ethyl ester was optimized by using response surface method with three variables per time. It was found that by optimizing four variables (temperature, load, flowate and modifier content) the production rate of the chiral resolution of racemic guaifenesin by cryogenic SFC could be increased severalfold compared to published results of similar application. A novel pressure-compensated design of industrial high pressure chromatographic column was introduced, using the technology developed in building the deep-sea submersibles (Mir 1 and 2). A demonstration SFC plant was built and the immunosuppressant drug cyclosporine A was purified to meet the requirements of US Pharmacopoeia. A smaller semi-pilot size column with similar design was used for cryogenic chiral separation of aromatase inhibitor Finrozole for use in its development phase 2.

Sensory auditory processing and intuitive sound detection : an investigation of musical experts and nonexperts

The auditory system can detect occasional changes (deviants) in acoustic regularities without the need for subjects to focus their attention on the sound material. Deviant detection is reflected in the elicitation of the mismatch negativity component (MMN) of the event-related potentials. In the studies presented in this thesis, the MMN is used to investigate the auditory abilities for detecting similarities and regularities in sound streams. To investigate the limits of these processes, professional musicians have been tested in some of the studies. The results show that auditory grouping is already more advanced in musicians than in nonmusicians and that the auditory system of musicians can, unlike that of nonmusicians, detect a numerical regularity of always four tones in a series. These results suggest that sensory auditory processing in musicians is not only a fine tuning of universal abilities, but is also qualitatively more advanced than in nonmusicians. In addition, the relationship between the auditory change-detection function and perception is examined. It is shown that, contrary to the generally accepted view, MMN elicitation does not necessarily correlate with perception. The outcome of the auditory change-detection function can be implicit and the implicit knowledge of the sound structure can, after training, be utilized for behaviorally correct intuitive sound detection. These results illustrate the automatic character of the sensory change detection function.

Neuronal oscillations in gamma- and alpha-frequency bands: from object representations to sensory awareness

The synchronization of neuronal activity, especially in the beta- (14-30 Hz) /gamma- (30 80 Hz) frequency bands, is thought to provide a means for the integration of anatomically distributed processing and for the formation of transient neuronal assemblies. Thus non-stimulus locked (i.e. induced) gamma-band oscillations are believed to underlie feature binding and the formation of neuronal object representations. On the other hand, the functional roles of neuronal oscillations in slower theta- (4 8 Hz) and alpha- (8 14 Hz) frequency bands remain controversial. In addition, early stimulus-locked activity has been largely ignored, as it is believed to reflect merely the physical properties of sensory stimuli. With human neuromagnetic recordings, both the functional roles of gamma- and alpha-band oscillations and the significance of early stimulus-locked activity in neuronal processing were examined in this thesis. Study I of this thesis shows that even the stimulus-locked (evoked) gamma oscillations were sensitive to high-level stimulus features for speech and non-speech sounds, suggesting that they may underlie the formation of early neuronal object representations for stimuli with a behavioural relevance. Study II shows that neuronal processing for consciously perceived and unperceived stimuli differed as early as 30 ms after stimulus onset. This study also showed that the alpha band oscillations selectively correlated with conscious perception. Study III, in turn, shows that prestimulus alpha-band oscillations influence the subsequent detection and processing of sensory stimuli. Further, in Study IV, we asked whether phase synchronization between distinct frequency bands is present in cortical circuits. This study revealed prominent task-sensitive phase synchrony between alpha and beta/gamma oscillations. Finally, the implications of Studies II, III, and IV to the broader scientific context are analysed in the last study of this thesis (V). I suggest, in this thesis that neuronal processing may be extremely fast and that the evoked response is important for cognitive processes. I also propose that alpha oscillations define the global neuronal workspace of perception, action, and consciousness and, further, that cross-frequency synchronization is required for the integration of neuronal object representations into global neuronal workspace.

Panel Cointegration of Chinese A and B Shares

This paper uses panel unit root and cointegration methods to test the stationarity of the premium on domestic investors’ A shares over foreign investors’ B shares and cointegration between the A and B share prices on the Chinese stock exchanges. We find that the A share price premium is nonstationary until 2001, when the A and B share markets were partially merged, and that the A and B share prices are cointegrated in the panel.Cointegration is more likely to be found for firms in the service sector and for firms that issued B shares recently.

Kotimaisen tuorekalan tuoreuden arviointi laatuindeksimenetelmällä QIM®

Kalateollisuus ja kalakauppa tarvitsisivat menetelmän, jolla kalan säilyvyyttä voitaisiin arvioida reaaliaikaisesti ja luotettavasti. Laatuindeksimenetelmä QIM® (engl. Quality Index Method) on käytössä jo useassa Euroopan maassa useille eri kalalajeille. QIM® pyrkii lajikohtaisesti ennustamaan aistinvaraisten ominaisuuksien muutoksien perusteella jäljellä olevaa säilyvyysaikaa. Työn tavoitteena oli luoda QIM® meressä kasvatetulle siialle. Tämä on ensimmäinen suomalaiselle kalalle tehtävä QIM®, ja tavoitteena on saada meressä kasvatetun siian QIM® myös viralliseen QIM®-käsikirjaan. Tutkimus tehtiin Elintarviketurvallisuusvirasto Eviralle. Tutkittavat kalat Evira osti Kalatukku E. Eriksson Oy:ltä. QIM®-tuloksen tueksi tutkittiin yhden erän pH ja indikoitiin pilaantuminen myös mikrobiologisesti. Luotiin myös kasvatetun siian profiili (arvioijia 13). Itse tutkimusosassa kaksi profiiliraatia (n = 9) ja QIM®-raati (n = 5) arvioivat raa’an ja kypsän kalan. Tulos varmistettiin myös aistinvaraisella kalan laadunarviointimenetelmällä (Evira 8001). QIM®-raati loi QIM®-luonnoksen ja luonnoksen toimivuutta testattiin. Kiinteänä osana työn toteutusta oli myös eri vaiheiden muutosten valokuvaus. Tämän tutkimuksen mukaan luotu QIM®-luonnos on toimiva pohja validoitaessaa QIM®-menetelmää siialle. Voidaan myös todeta, että QIM® soveltuu meressä kasvatetulle siialle. Kypsän kalan aistinvaraisella laadunarviointimenetelmällä (Evira 8001) analysoitiin säilytysajankohta, jolloin kypsästä kalasta voitiin todeta kalan kauppakelvottomuus – tätä pidettiin ajanhetkenä, jolloin raa’an kalan tutkiminen voitiin lopettaa. Tutkimuksessa käytetty mikrobiologinen menetelmä ”Mikrobien lukumäärän määrittäminen” (Evira 3420/1) korreloi QIM®-tuloksen kanssa; kalanäyte oli tässä tutkimuksessa niin mikrobiologisesti arvioituna kuin laatuindeksinkin mukaan käyttökelvotonta viidentenätoista päivänä. Tutkittujen kalojen pH-arvoja ei voitu verrata laatuindeksiin, sillä tässä tutkimuksessa mitattujen pH-arvojen tuloksista ei voitu päätellä pilaantumisen etenemistä. Kun QIM® meressä kasvatetulle siialle on validoitu (Evira), valmista meressä kasvatetun siian QI-menetelmää voidaan hyödyntää jatkossa Suomen kalateollisuudessa ja -markkinoilla. Olisi hyvä, jos QIM® luotaisiin myös muille Suomen yleisimmille kauppakaloille, jotta pakkauksiin merkityt viimeiset käyttöpäivät perustuisivat yhteen yhteiseen menetelmään ja näin viimeisellä käyttöpäivällä olisi tieteellinen pohja.