Thesis (doctoral)--Universität der Bundeswehr, München, 2000. / Includes bibliographical references (p. 165-172).

Thèse de doctorat : Chimie organique : Strasbourg 1 : 2007. / Titre provenant de l'écran-titre. Bibliogr. p. 207-216.

Thesis (Ph. D.)--Institute of Paper Chemistry, 1942. / Includes bibliographical references (p. 83-84).

Thesis (Ph. D.)--Institute of Paper Chemistry, 1967. / Includes bibliographical references (p. 78-80).

Thesis (Ph. D.)--Institute of Paper Chemistry, 1966. / Includes bibliographical references (p. 109-112).

The West Florida Shelf (WFS), typically characterized as being oligotrophic, is one of the most productive continental shelves in the United States. In addition to supporting a large fishing industry, the WFS also supports high biomass blooms of the toxic dinoflagellate Karenia brevis. Because of the large ecological and economic impacts these blooms have on the area, the ECOHAB: Florida program was developed to gain a better understanding of red tides and their initiation, maintenance, and dispersal. This interdisciplinary program consisted of monthly cruises from June 1998 through December 2001, with a hiatus from January through March of 2001. Hydrography, nutrients, chlorophyll a, phaeopigments, and a wide variety of other factors were measured during the cruises. In this paper chlorophyll a and phaeopigment concentration, nutrients, and hydrographic data were examined to explain the temporal and spatial distribution of chlorophyll on the shelf. Average surface chlorophyll values were 0.55 mg/m 3 with near bottom values averaging 0.85 mg/m 3. Chlorophyll was found to be highest near the estuaries of Tampa Bay and Charlotte Harbor with a decreasing gradient seaward. Near bottom chlorophyll values were generally two to fourfold greater than surface values. Midshelf stations (35- 50 m) were characterized by high near bottom chlorophyll, whereas the offshore stations (86-200 m) were characterized by a subsurface chlorophyll maximum ranging between 40 to 80 m deep. Nutrients were generally low across the shelf except for 1998 when a subsurface intrusion of nutrient rich slope water reached to the 20 m isobath. Temperatures ranged from 14.00 ° C to 31.47° C. Salinity ranged from 30.5 to 37.50 in the study area. Four blooms of Karenia brevis, lasting several months, contributed to the high chlorophyll concentrations along the inner shelf. Maximum chlorophyll concentrations of 27.10 mg/m 3 were a result of the October 1999 to March 2000 red tide. Blooms of Trichodesmium and diatoms also were contributors to patterns seen on the shelf. Maximum chlorophyll values were generally highest in the late summer and fall except for offshore values which showed little to no seasonality. Inshore of the 50 m isobath, average phaeopigments comprised from 43 to 68 percent of the measured Chl a, while offshore values were from 68 to over 100 percent. Inshore chlorophyll distributions were attributed to riverine and estuarine flux of nutrients, localized upwelling, and recycling of nutrients aided by salinity and temperature fronts. Midshelf distributions were attributed to the movement of biologically important material through the bottom Ekman layer from offshore to the inshore regions of the shelf. Offshore distributions were attributed to Loop Current upwelling and synoptic scale processes associated with seasonal meteorological forcing.

Tiriant didėjančių temperatūrų ir drėgmės deficito poveikį sėjamųjų žirnių biometriniams ir biocheminiams rodikliams, bandymai atlikti LSDI Augalų fiziologijos laboratorijos fitotroniniame komplekse 2009 metais. Tirta didėjančių temperatūrų ir drėgmės deficito įtaka sėjamųjų žirnių (Pusum sativum L.) 'Gloriosa' antžeminės dalies augimui, žaliųjų bei sausųjų medžiagų kaupimuisi antžeminėje dalyje, asimiliaciniam lapų plotui ir fotosintetinių pigmentų kiekiui. Atlikus tyrimus nustatyta, kad, didėjant temperatūrai ir mažėjant substrato drėgmei chlorofilų a ir b bei karoteno kiekis sėjamųjų žirnių daiguose, didėja. Iš tyrimų duomenų matyti, kad didžiausias sausųjų medžiagų kiekis buvo daiguose, kurie augo normalaus drėgnio (40 - 45%) substrate, aukštesnėje - 25/18 °C temperatūroje. Sėjamųjų žirnių didžiausias daigų lapų plotas buvo prie žemesnės temperatūros ir normalaus substrato drėgnio (40 - 45%). Aukščiausi daigai buvo normalaus drėgnio (40 - 45%) substrate ir prie - 25/18 °C temperatūros. Tyrimai parodė, kad kompleksinis drėgnio ir aukštos temperatūros poveikis skatina žirnių daigų augimą. Taip pat iš duomenų matosi, kad normalus (40 - 45%) substrato drėgnis ir aukštesnė - 25/18 °C temperatūra skatina asimiliacinį žirnių daigų lapų plotą. / A study of rising temperatures and water deficit effects on pea biometric and biochemical characteristics was conducted at LSDI. It was accomplished at Plant Physiology Laboratory fitotronical complex in 2009. The research was made on the influence of rising temperatures and water deficit on pea (Pisum sativum L.) 'Glorioso' canopy growth, green and dry matter accumulation in terrestrial, assimilated leaf area and photosynthetic pigment content. The investigation showed that with increasing temperature and decreasing the substrate moisture of chlorophylls a and b and carotene content of pea shoots have been rising. The survey data shows that the highest dry material concentrations was of the shoots, which grew at normal humidity (40 - 45%) substrate and higher temperature - 25/18 ° C. The highest pea shoots leaf area was lower at normal temperature and substrate moisture (40 - 45%). Tallest plants were normal humidity (40 - 45%) and the substrate - 25/18 ° C temperature. Studies have shown that a complex of high humidity and temperature on pea plants promote growth. Also the data shows that normal (40 - 45%) substrate moisture content and higher - 25/18 ° C temperature promotes assimilation of pea sprouts leaves area.

The oxidation reaction mechanisms of water soluble textile dyes amaranth (an azo dye), brilliant blue-R (a triaryl dye) and safranine-O (an azine dye) with oxidants- hypochlorite and chlorine dioxide, were investigated. The detailed kinetics of the reactions of the three dyes was studied under excess concentrations of the oxidant and other reagents. The depletion of concentration of the chosen dye, taken at low concentration was monitored using a Hi-Tech SF-61 DX2 double mixing micro volume stopped-flow apparatus. The hypochlorite initiated oxidations were investigated as function of varying concentration of oxidant and hydrogen ion, ionic strength and temperature. For the chosen dyes and reaction conditions, the depletion of dye followed pseudo first-order kinetics and the rate constants were estimated using KinetAsystTM software. All the three reactions had first-order dependence on the oxidant concentration, and the reaction rates increased by varied extent with increase in [H+]0. The role of acid in their reaction mechanisms was established. The kinetic data was analysed to evaluate the rate constants for the competitive pathways initiated by hypochlorite ion and hypochlorous acid. The overall second-order rate coefficients for the OCl- and HOCl initiated reactions were estimated for all the three reactions. Major oxidation products for the reactions were separated and characterized by 1H NMR and 13C NMR and GC-MS techniques and the stoichiometry was established. The energy parameters inclusive of Arrhenius factor, enthalpy, entropy and energy of activations for the oxidation of three dyes both by OCl- and HOCl species were estimated. Based on the experimental findings, the probable rate laws, mechanisms and reaction schemes were described. Simulations studies were conducted to validate the proposed mechanisms using SIMKINE2 computer programme. The rate of oxidation of safranine-O is greater than that of amaranth and brilliant blue-R with OCl- / HOCl reaction. Following similar protocol, the oxidations of the chosen dyes with chlorine dioxide were investigated by monitoring the depletion kinetics of dye as function of varying concentration of ClO2 and OH- ion, ionic strength and temperature. All the three dyes, exhibited pseudo first-order kinetics and the rate constants were estimated using KinetAsystTM software. All the three reactions had first-order dependence on the oxidant concentration at pH conditions 7.0, 8.0 and 9.0 suggesting that reaction mechanism remains unaltered with pH variation. The effect of hydroxide ion on the reaction rate revealed that it acts as catalyst. All the three reactions had first-order dependence on [OH-]0, when its concentration was low; but the order with respect to [OH-] decreased as [OH-] increased stoichiometry proportion to reactants. The catalytic constant for hydroxide catalysed reaction was estimated for all the three reactions. Kinetic salt effect experiments were conducted to identify the possible reaction species involved in the reactions. The major reaction products were characterized by 1H NMR, 13C NMR and GC-MS techniques. The stoichiometry ratios were established and energy parameters were estimated. The rate laws and probable reaction mechanisms were proposed and appropriate reaction schemes for all the reactions were described. The elucidated mechanisms were confirmed by simulation studies using SIMKINE2 software. At neutral pH the rate of oxidation of amaranth is greater than safranine-O and brilliant blue-R, and brilliant blue R being the slowest. / Thesis (Ph.D.)-University of KwaZulu-Natal, Westville, 2010.

The phytochemistry of Ochna serrulata (Hochst.) Walp. was investigated for the first time; two new dimeric chalcones (5-deoxyurundeuvine C and serrulone A) and two new biflavonoid derivatives (4,4’,7-tri-O-methylisocampylospermone A and 4”’-de-Omethylafzelone A) were isolated. These compounds were isolated along with the known compounds lophirone A, afzelone B, campylospermone A, isocampylospermone A, ochnaflavone, 2”,3”-dihydroochnaflavone, lophirone C, psilosin, 3’-O-methylpsilosin, a cyanoglucoside, epicatechin, (2’,4’- dihydroxyphenyl)acetic acid, methyl (2’,4’-dihydroxyphenyl)acetate, irisolone 4’- methyl ether, iriskumaonin 3’-methyl ether, 3',4'-dimethoxy-6,7-methylenedioxyisoflavone, lophirone L, syringaresinol and 16α,17-dihydroxy-entkauran-19-oic acid. The growth inhibitory effect of these compounds was evaluated against three cancer cell line panel of TK 10 (renal), UACC62 (melanoma) and MCF7 (breast) using a sulforhodamine B (SRB) assay. Ochnaflavone and 3’-methoxypsilosin demonstrated selectivity and only inhibited the growth of melanoma cancer cells. However, ochnaflavone showed higher activity by totally inhibiting the growth of melanoma cancer cells at 12.91 μM, whereas, 3’-O-methylpsilosin has this effect at a concentration of 14.11 μM. Lophirone C, a dimeric chalcone, demonstrated the highest cytotoxic activity amongst all isolated compounds against renal, melanoma and breast cancer cells with TGI at 35.63 μM, 11.67 μM and 30.35 μM, respectively. Lophirone A, a rearranged biflavonoid, showed TGI against these cancer cells at 58.96 μM, 26.23 μM and 40.01 μM, respectively. The rest of the compounds showed no significant cytotoxicity against the three cancer cells. The new biflavonoid, 4,4’,7-tri-O-methylisocampylospermone A demonstrated the highest antimalarial activity against chloroquine-resistant strains of Plasmodium falciparum (FCR-3) with IC50 of 11.46 μM, followed by ochnaflavone (17.25 μM). iv Serrulone A (26.52 μM), lophirone A (29.78 μM), 5-deoxyurundeuvine C (31.07 μM), lophirone C (35.31 μM), 4”’-de-O-methylafzelone A (38.43 μM), afzelone B (39.54 μM), irisolone 4’-methyl ether (40.72 μM) and syringaresinol (42.66 μM) were moderately active. The following compounds exhibited the lowest antimalarial activity, 2”,3”-dihydroochnaflavone (61.86 μM), iriskumaonin 3’-O-methyl ether (93.69 μM),3’- O-methylpsilosin (106.35 μM) and16α,17-dihydroxy-ent-kauran-19-oic acid (106.48 μM). Owing to the observed and reported biological/pharmacological activity, ochnaflavone (an ether-linked biflavone consisting of apigenin and luteolin moieties) was selected for synthetic studies. An older method, nucleophilic aromatic substitution (SNAr) was successfully applied in the construction of the diary ether. Oxidative ring cyclization of the ether-linked dimeric chalcone was achieved by using heated pyridine and iodine. The two methods can be extended further in the synthesis of other novel biflavones with ether linkage. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.

Oxalis reclinata Jacq., is a dicotyledonous plant. O. reclinata belongs to the family Oxalidaceae. This plant produced callus which accumulated red coloured anthocyanin pigments when cultured in vitro. The levels of anthocyanin accumulated by O. reclinata callus were higher than in the intact plant. The major pigment was isolated and identified as cyanjdin-3-glucoside (CROUCH, VAN STADEN, VAN STADEN, DREWES & MEYER, 1993). In nature, anthocyanins are responsible for orange, red, purple and blue colouration of certain tissues of higher plant s. Due to the toxicity of many synthetic red colouring agents, anthocyanins are regarded as potential substitutes for synthetic food colourants. This research was aimed at investigating mechanisms which induce pigment production as well as to optimize anthocyanin yield from callus cultures of O. reclinata, once anthocyanin production was stimulated. Pigmented and non-pigmented callus lines were generated from O. reclinata (CROUCH & VAN STADEN, 1994) and maintained on MURASHIGE & SKOOG (1962) agar medium (O.8% [w/v], pH 5.7) supplemented with 0.5 mgℓ ¯¹ BA, 5 mgℓ ¯¹ NAA, 30 gℓ ¯¹ sucrose and 0.1 gℓ ¯¹ myo-inositol. Plant tissue culture studies were conducted on red and white lines of O. reclinata to optimize callus yield and anthocyanin production in vitro. This involved manipulating contributory factors of the culture environment (carbohydrates, nitrates, phosphates, phytohormones, light and temperature). In vitro studies showed that, light played an inductive role in anthocyanin production in callus cultures of O. reclinata. The auxin, 2,4- dichlorophenoxyacetic acid (2,4-D) reduced pigment production but increased callus biomass. This hormone probably exerted its effect by reducing the pool of anthocyanin precursors, such as phenylalanine, resulting in increased primary metabolic activity. Suspension cultures were shown to be a viable means of propagating pigmented callus cells of O. reclinata. The growth curves for red and white callus cells were determined using the settled cell volume (SCV) method. Pigmented cell cultures grew for longer periods compared to nonpigmented cells of O. reclinata. White callus cells reached the stationary phase after 18 days. Red callus cells continued growing exponentially for an extra three days compared to white callus cells. The vacuole was identified as the organelle where anthocyanins accumulate using the light microscope. The molecular techniques of two-dimensional electrophoresis and in vitro translation were utilized to analyze differences in gene expression between white and red callus cultures of O. reclinata. Thus far, two-dimensional electrophoresis has shown that the red callus of O. reclinata had more polypeptides compared to the white callus. The level of gene expression was higher in the red callus compared to white callus, as revealed by nonradioactive in vitro translation. With optimization of radioactive in vitro translation, identification of specific structural anthocyanin genes which are under regulatory control should be possible. Future research should aim at acquiring a better understanding about the genetic control of anthocyanin biosynthesis in order to manipulate this pathway effectively. / Thesis (M.Sc.)-Univesity of Natal, Pietermaritzburg, 1996.