A thesis submitted to the Faculty of Science, University of the Witwatersrand Johannesburg. In fulfilment of the requirements for the Degree of Doctor of Philosophy. March 2017 / In this PhD thesis, we report for the first time, new methodology for the synthesis of angucycline antibiotic natural products. In particular, for the synthesis of 1,8-dihydroxy-3methyltetraphene-7,12-dione, commonly known as tetrangulol. We also report on the synthesis of 1,10,12-trimethoxy-8-methylbenzo[c]phenanthridine in our quest to synthesise phenanthroviridone from an intermediate product in the synthesis of tetrangulol. The Suzuki-Miyaura coupling reaction between 1,4,5-(trimethoxynaphthalen-2-yl)boronic acid and 2-iodo-3-methoxy-5-methylbenzaldehyde afforded intermediate, 3-methoxy-5methyl-2-(1,4,5-trimethoxynaphthalen-2-yl)benzaldehyde. Conversion of this benzaldehyde into the alkyne, 2-(2-ethynyl-6-methoxy-4-methylphenyl)-1,4,5-trimethoxynaphthalene was accomplished utilizing the Corey-Fuchs reaction. Exposure of the derived acetylene to a catalytic platinum(II)-mediated ring closure yielded the required tetracyclic aromatic product, 1,7,8,12-tetramethoxy-3-methyltetraphene which was converted into tetrangulol. Exposure of the related 3-methoxy-5-methyl-2-(1,4,5-trimethoxynaphthalen-2-yl)benzaldehyde O-phenyl oxime to microwave irradiation in an ionic liquid yielded 1,10,12-trimethoxy-8methylbenzo[c]phenanthridine, instead of the desired natural product phenanthroviridone. We also report on the unexpected synthesis of the benzonaphthopyranone core found in other classes of angucycline antibiotics from oxygen analogs of 2-naphthylbenzyl alcohols when exposed to N-bromosuccinimide. Treatment of (2-(1,4-dimethoxynaphthalen-2yl)phenyl)methanol and related analogues with N-bromosuccinimide under an oxygen atmosphere afforded 12-methoxy-6H-dibenzo[c,h]chromen-6-one, 2-Methoxy-6Hbenzo[c]chromen-6-one and of 6H-benzo[c]chromen-6-one. An investigation into possible mechanisms for this transformation was also conducted. / LG2017

A thesis submitted to the Faculty of Science University of the Witwatersrand Johannesburg In fulfilment of the requirements for the Degree of Doctor of Philosophy June 2015 / The first two chapters of this thesis deals with the synthesis of 6H-benzo[d]-naphtho[ 1,2- b]pyran-6-one motif found in gilvocarcin as well as related aromatic compounds containing the aromatic pyranone moiety. The synthesis was undertaken by employing the Suzuki- Miyaura cross coupling reaction and a novel N-bromosuccinimide induced ring cyclization reaction to afford the pyranone. It was established that the treatment of both [2-(1,4- dimethoxynaphthalen-2-yl)phenyl]methanol and (2',5'-dimethoxy-[1,1'-biphenyl]-2- yl)methanol separately with N-bromosuccinimide results in the unexpected synthesis of a naphthopyranone ring system in the form of 12-methoxy-6H-dibenzo[c,h]chromen-6-one and 2-methoxy-6H-benzo[c]chromen-6-one respectively. Application of the same methodology for the attempted synthesis of related compounds namely, 1-hydroxy-12-methoxy-6Hdibenzo[ c,h]chromen-6-one and 8-fluoro-12-methoxy-6H-dibenzo[c,h]chromen-6-one unfortunately did not generate the desired results. Attempts were made to elucidate the mechanism of this reaction. The most apparent mechanism indicates that Nbromosuccinimide, in the presence of air, oxidizes the benzylic alcohol to an aldehyde which is then converted to an acid bromide allowing for the ring closure with the adjacent aromatic ether to afford the desired pyranone. In Chapter 3 and 4 of this thesis we dealt with the synthesis of benzo[b]phenanthridine-7,12- dione motif, the backbone of biologically important secondary metabolite jadomycin B. Again, a key step involves employing the Suzuki-Miyaura cross coupling reaction. The synthetic methodology also sheds some light on the dynamics of the ring closure of benzylic amines onto naphthoquinones resulting in the synthesis of benzo[i]phenanthridine-11,12- dione, 12-methoxybenzo[i]phenanthridine and 1-hydroxybenzo[i]phenanthridine-11,12-dione. The synthesis of benzo fused phenanthridines has been undertaken in Chapter 5 and 6 by employing Suzuki-Miyaura cross coupling reaction and a potassium t-butoxide and light mediated cyclization reaction as the key steps. The synthesis of 5- phenylbenzo[i]phenanthridine was undertaken successfully but attempts to execute the same methodology to form a compound library of related benzo-fused phenanthridines was unsuccessful. The same methodology employing a Suzuki-Miyura cross coupling reaction and potassium tbutoxide and light mediated cyclization reaction was applied in Chapter 7 and 8 of the thesis directed towards the synthesis of 13H-indolo[3,2-c]acridine and 3-methoxy-13H-indolo[3,2- c]acridine. The successful synthesis of the 13H-indolo[3,2-c]acridine is reported using this methodology.

We report here the development of new and more general synthetic pathways for the preparation of allenyl and alkynyl carbonyls. These highly dense functionalized compounds were utilized as key intermediates for the synthesis of [3.2.1] and [3.3.1] bicyclic framework, the motifs found in many natural products. A convenient method described for the dehydration of ketoesters to generate conjugated and deconjugated alkynyl esters and conjugated allenyl esters. This sequential one-pot method involves the formation of a vinyl triflate monoanion intermediate that leads to the selective formation of alkynes or allenes depending on additives and conditions used. Product outcomes appear to be a function of unique monoand dianion mechanisms which are described. Our design of a Morita-Baylis-Hilman (MBH) reaction to include a fast silyl 1,3- Brook rearrangement has enabled the first ever anion-catalysis. This new reaction makes possible the addition of both aliphatic and aromatic aldehydes to s ilylallenes leading to carbinol allenoates. These new MBH reactions products allow for a fasttracked synthesis of [3.2.1] bisoxa-bicycles which make up the framework of many biologically active natural products including Vitisinol D. The development of cyclic addition of hydrazine nitrogen to unactivated alkynes catalyzed by non-metals is reported. Starting from readily accessible silyl allenyl esters, alkynyl hydrazines are prepared in one step and subsequently undergo unprecedented cyclization reactions in the presence of ammonium and phosphonium catalysts leading to dehydro-azaproline products. These heterocycles were also produced in high enantiomeric excesses using chiral ammonium phase transfer catalysts via a kinetic resolution pathway. / The racemic synthesis of fully functionalized bicyclic core of Vitisinol D was achieved using allenyl ester as a key intermediate. The required electron withdrawing group (EWG) at the position was screened for better addition followed by the compatibility towards successive transformation and, finally, the ease of removal. A reductive aldol method to transform lactone-enol to the desired [3.2.1] bicycle was extensively studied to understand the stereoelectronic requirements for the formation of such bicyclic structures. Due to the necessity of selective protection and deprotection of many phenolic and aliphatic hydroxyls as well as ester groups, orthogonal protecting groups were established accordingly. / by Pradip Maity. / Thesis (Ph.D.)--Florida Atlantic University, 2011. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2011. Mode of access: World Wide Web.

Os Processos Oxidativos Avançados (POAs) têm sido largamente empregados para o tratamento de efluentes contendo compostos orgânicos altamente tóxicos, que por sua vez, são dificilmente degradados pelos sistemas de tratamento biológico convencional. Além disso, os tratamentos físico-químicos, como filtração, adsorção e floculação, não destroem o composto tóxico, e sim, apenas transferem-no para outra fase, causando um subseqüente problema de descarte. A principal barreira para a aplicação do POA em escala industrial é o alto custo relacionado à utilização da radiação ultravioleta (UV). Desta maneira, torna-se interessante desenvolver um reator com uma fonte artificial de radiação UV de custo reduzido. Neste trabalho, foi projetado um reator tubular fotoquímico de aço inox 304 que apresenta um conjunto de 12 lâmpadas fluorescentes como fonte de radiação UV (40W/lâmpada), posicionadas verticalmente na superfície interna do mesmo. O processo estudado foi o processo foto-Fenton, que consiste em uma combinação de íons ferrosos, peróxido de hidrogênio e radiação UV, aplicado na degradação de um efluente aquoso contendo fenol como poluente modelo (100–500 mgC.L-1). Os resultados experimentais indicaram que a taxa de degradação aumenta com a radiação UV, até atingir a saturação de fótons da luz UV . Com o objetivo de verificar a influência das variáveis de processo, foi realizado um planejamento experimental, no qual possibilitou-se obter um modelo para o processo e a respectiva superfície de resposta. Neste processo foi utilizada uma combinação de Fe2+ (0,27–30 mM), H2O2 (0,2–6 moles) e radiação UV, chegando-se a uma mineralização de 82% para 100 mgC.L-1 de fenol e 81% para 500 mgC.L-1 de fenol. Devido à complexidade apresentada pelo processo foto-Fenton, foi aplicado outro tipo de modelagem matemática, baseado na técnica de redes neurais artificiais (RNA), chegando-se a um coeficiente de determinação de 99% entre os valores experimentais e os valores calculados pelo modelo. / Advanced Oxidation Processes (AOPs) have been largely used for the treatment of wastewaters containing highly toxic organic compounds, which are hardly degraded by the conventional biological systems. Besides, the physicalchemical treatments, such as filtration, adsorption and flocculation, do not destroy the target compounds, which are simply transferred to another phase, causing a subsequent problem of disposal. The main barrier for the application of the POA in industrial scale is the high cost related to the use of ultraviolet radiation (UV) sources. Therefore, it has been proposed a development of a reduced cost reactor with an artificial source of UV radiation. In the present work, a tubular photochemical reactor was developed, which is made in stainless steel and presents a row of 12 fluorescent lamps as the UV radiation source (40W/lamp), attached vertically onto the inner surface of the reactor. It has been studied the photo-Fenton process, that consists in a combination of ferrous ions, hydrogen peroxide and UV radiation, applied in the degradation of an aqueous solution containing phenol as pollutant model (100–500 mgC.L-1). The experimental results indicated that the degradation rate increases as the UV irradiance increases. In order to verify the influence of the process variables in phenol degradation, an experimental design was carried out by the response surface method and the corresponding polynomial model was determined. In this process, it was used a combination of Fe2+ (0,27–30 mM), H2O2 (0,2–6 moles) and UV radiation. The mineralisation efficiency was 82% for phenol 100 mgC.L-1 and 81% for phenol 500 mgC.L-1. Due to the complexity presented by the photo-Fenton process, another type of mathematical modelling was applied, based on the artificial neural network (ANN), obtaining 99% of coefficient of determination between the experimental values and the values calculated by the model.

Orientador: Marcio José Tiera / Banca: Carla Cristina Schmitt Cavalheiro / Banca: Iêda Aparecida Pastre Fertonani / Resumo: O presente trabalho apresenta a síntese, caracterização e estudo da auto-associação em solução aquosa de derivados anfifílicos zwiteriônicos de quitosana com potencial para o transporte e a liberação controlada de fármacos. Derivados anfifílicos foram obtidos a partir de quitosana previamente desacetilada e degradada, que foram submetidos à reação de adição de Michael com o monômero hidróxido de 1-(3-sulfopropil)-2-vinilpiridina (SPP). O derivado hidrofílico obtido foi posteriormente por modificado com o grupo dodecil aldeído (DD) por meio de reação de aminação redutiva. Os graus de substituições (GS) pelos grupos DD e SPP foram determinados utilizando as técnicas de espectroscopia de ressonância magnética nuclear de hidrogênios RMN de 1H, espectroscopia no infravermelho IV e titulação potenciométrica essas técnicas foram utilizadas para caracterizar a quitosana e seus derivados. Os graus de substituição por SPP foram de 36 e 46% e com grupos dodecil variaram de 2 a 10%. A massa molar média foi determinada utilizando cromatografia de permeação em gel (GPC). E o estudo do comportamento associativo em meio aquoso foi realizado utilizando-se a espectroscopia de fluorescência, espectroscopia no UV-Vis, espalhamento de luz dinâmico (DLS) e microscopia eletrônica de transmissão (TEM). Os derivados hidrofílicos permaneceram solúveis em toda a faixa de pH e os derivados anfifílicos demostraram um comportamento similar aos surfactantes convencionais. As concentrações de agregação crítica (CAC), foram determinadas com a sonda fluorescente o pireno, os valores variaram de 0,005 até 0,017 g L-1 foi observado um decréscimo nos valores com o aumento do conteúdo hidrofóbico e pH. Medidas de DLS mostraram que os derivados formam agregados com diâmetros que variam de 100 a 1000 nm e o potencial zeta varia de acordo pH da solução. Imagens de TEM mostraram agregados esféricos de tamanhos variados ... / Abstract: This work presents the synthesis, characterization and self-association study of amphiphilic zwitterionic derivatives of chitosan in aqueous solution as potential drug delivery systems. Amphiphilic derivatives were obtained from deacetylated and degraded chitosan, followed by Michael addition reaction with the monomer 1-(3-sulfopropyl)-2-vinylpyridine hydroxide (SPP). The hydrophilic derivative was further modified with dodecyl groups (DD) by reductive amination reaction. The degrees of substitution (DS) by DD and SPP groups were determined using H1-NMR, and FTIR and potentiometric titration techniques were used to characterize chitosan and its derivatives. The degrees of substitution by SPP were 36 and 46 % and by dodecyl groups varied from 2 to 10%. The average molecular weights were determined using the gel permeation chromatography (GPC). The study of the selfassociation in aqueous solution was performed by using fluorescence spectroscopy, UV-Vis, dynamic light scattering (DLS) and transmission electron microscopy (TEM) techniques. The hydrophilic derivatives were soluble in all pH range and the amphiphilic derivatives exhibited self-association behavior similar to conventional surfactants. The critical aggregation concentrations, determined from pyrene fluorescence, varied from 0.005 to 0.017 g l-1 and were shown to decrease with both, the increasing hydrophobic content and pH. DLS measurements showed that self-association of the amphiphilic derivatives leads to formation of aggregates having diameters varying from 100 to 1000 nm and the zeta potential varied according with the pH. The TEM images showed spheroidal aggregates of varied sizes in accordance with DLS measurements. Quercetin was used as a model for drug loading study and the results showed that solubilizing capacity increased from 17 to 54% with the hydrophobic content of the ... / Mestre

Thesis (MTech (Horticulture))--Cape Peninsula University of Technology, 2018. / Global demand for environmentally-friendly grapevine cultivation and pest control has necessitated an improved understanding of the relationship between soil properties and beneficial naturally occurring antagonists like entomopathogenic fungi (EPF). This group of fungi presents a viable alternative for the control of destructive pests such as the grapevine mealybug. Sixty-six soil samples were collected from 22 vineyards in the Western Cape, South Africa. The association between soil nutrient status and EPF prevalence was then examined. Fungi were isolated with methods of insect baiting and selective media. Fungal strains were identified and characterized using light microscopy and DNA analysis (ITS and BTub). In addition, fungal isolates were tested against a key grapevine pest, Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae) using an immersion bioassay at a concentration of 1 x 108 conidia ml-1. Twenty-three fungal strains were isolated and correspondence analysis (CA) of data indicated a positive association between fungal occurrence and moderate to high levels of soil-based macronutrients. Binomial logistic regression analysis revealed that soil N, K, Ca, Mg and S concentrations and C/N ratio were correlated with at least one EPF species. This study showed that some soil nutrient properties correspond to greater occurrence of EPF in grapevine soils. Strains of Beauvaria bassiana (Hypocreales: Clavicipitaceae) caused the highest mortalities (82% to 87%). In chapter three, I examined the effect of B. bassiana inoculation of grape plants on the infestation level of P. ficus, and the growth and volatile constituents of potted grape plants. The grapevines were inoculated with 1 x 108 conidia ml-1 of B. bassiana by drenching before experimentally infesting them with thirty P. ficus adult females. At four weeks post treatments, the fungus was re-isolated from leaves of 50% of the fungus exposed plants. No significant difference (P > 0.05) was observed in all the plant growth parameters measured in the fungus treated and control plants. Plant tissue analysis revealed markedly higher contents of Ca and Mg in leaf tissue of plants exposed to the B. bassiana relative to the control. GC-MS analyses showed that a significantly (X2=5.1; P<0.02) higher number of known anti-insect volatile compounds (9) including napthtalene were present among fungus treated plants compared to the control plants (5). However, B. bassiana did not have any significant effect on total polyphenol, alkaloid and flavonoids. Overall, treatment with fungus did not offer any protection against infestation of P. ficus. In conclusion, this is the first study to report on the isolation of indigenous entomopathogenic fungal (EPF) strains within vineyards of the Western Cape. The study revealed that inoculating grapevine plants during cultivation had a net positive effect on the production of volatile compounds in grapevines. These findings shed light on the mechanisms involved in endophytic fungus-plant-insect interactions. This study contributes valuable information to future development of ecological approaches involving EPF for insect control in vineyards and in general, agricultural settings.

The main focus of this thesis is to present the structural and photophysical characteristics of the coordination polymers [Ln(C7H3NO4)(C7H4NO4)(H2O)]n (Ln is Pr, Nd, Sm, Eu, and Tb), as well as attempting to synthesize the novel organic linker 4,4'(4,8-Dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-diyl)dibenzoic acid (BDTDC). Various lanthanide salts were coordinated with 2,3-pyridinecarboxylate (2,3- pydc) via hydrothermal synthesis. ... Progress was made toward the synthesis of a novel metal-organic framework linker BDTDC. Synthesis of the intermediate benzo[1,2-b:4,5-b']dithiophene as well as the determination of the crystal structure, were performed successfully and are reported herein. / by Amanda Lyn Staggeer Ramirez. / Thesis (M.S.)--Florida Atlantic University, 2013. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

Thesis (DTech(Chemistry)) --- Cape Technikon, Cape Town, 1996 / A new general synthetic strategy for the synthesis of benzo[c]pyranquinones, with a view to making the route more generally applicable to the synthesis of naturally occurring naphtho[2,3-c]pyranquinones of potential importance as antimicrobial agents, has been developed. This synthetic approach afforded, inter alia, the natural products, is oeleutherin and hongconin (as their racemates) in good overall yield. A new high-yielding synthetic route for the synthesis of 1,5-dimethoxy-4naphthol, 2-allyl-5-methoxy-I,4-naphthoquinone and 3-acetyl-5-methoxy-I,4naphthoquinone, all ofwhich are key intermediates in several laboratory routes to naturally occurring naphtho[2,3-c]pyranquinones, has also been developed. A key-step in their formation is respective methylation, allylation or acetylation of a common intermediate Diels-Alder adduct. A feasible route to a naphtho[2,3-c]pyranone was developed. This model route is envisaged to be generally applicable for the synthesis of higher oxygenated naphtho[2,3-c]pyranones by virtue ofthe nature of the conditions and reagents used in this synthetic route. The target quinones and some of their precursors were evaluated for antimicrobial activity and specificity in vitro. This showed that the benzo[c]pyranquinones have a broader specificity spectrum than their naphtho[2,3-c] or naphtho[2,3-b] analogues.

O petróleo é uma das principais fontes de energia e também de poluição no mundo atual. Novas tecnologias na indústria petroquímica visam diminuir a energia gasta no processamento e a redução dos produtos poluidores. Compostos de enxofre e nitrogênio geram problemas ambientais, sendo os mais relevantes, a poluição da atmosfera que afeta a saúde da população diretamente. A tecnologia nuclear tem sido usada na proteção ambiental através da remoção de poluentes pela reação com radicais livres produzidos pela ação da radiação nas moléculas de água. O objetivo desse trabalho é a avaliação do efeito da radiação ionizante no petróleo e no diesel, principalmente, nos hidrocarbonetos, nos compostos orgânicos sulfurados e nos nitrogenados. Para tanto estudou-se a molécula modelo de enxofre, benzotiofeno, e amostras de diesel e de petróleo bruto. As amostras foram irradiadas na fonte de Co-60 do tipo Gammacell. A concentração total de enxofre nas amostras foi determinada por fluorescência de raios x e os compostos orgânicos foram determinados por cromatografia gasosa acoplada ao espectrômetro de massas,GC-MS. O estudo com a molécula modelo demonstrou que cerca de 95% foi degradado com uma dose absorvida de 20 kGy. Os resultados obtidos na análise dos hidrocarbonetos demonstram que estes foram craqueados quando irradiados com a dose de 15 kGy, entretanto observouse a polimerização e a baixa eficiência no craqueamento em doses maiores. Observou-se eficiência na redução da maioria dos compostos de enxofre do petróleo e diesel. Considerando as doses estudadas as que apresentaram melhor eficiência foram as de 15 kGy e 30 kGy. Na amostra de diesel as maiores variações nos compostos orgânicos foi observada com doses absorvidas de 30 kGy e 50 kGy. No petróleo, após a destilação e separação cromatográfica de coluna aberta utilizando cloreto de paládio como fase estacionaria, observou-se a separação preferencial de compostos orgânicos sulfurados. / Petroleum is the most important energy and pollution source in the world, nowadays. New technologies in petrochemical industry aim to minimize energy spending at the process and to reduce pollution products. Sulfur and nitrogen compounds generate environmental problems; the most relevant is air pollution that affects the population health directly. The nuclear technology has been used in environmental protection through pollutants removal by free radicals produced at action of the radiation in water molecule. The objective of this study is to evaluate the radiation effects on oil and diesel, mainly in the hydrocarbons, organic sulfur, and nitrogen compounds. It was studied a molecule model of sulfur, named benzothiophene, diesel and crude oil samples. The samples were irradiated using a Co-60 source, Gammacell type. The total sulfur concentration in the samples was determined by X-ray fluorescence spectrometry, and organic compounds were analyzed by gas chromatography coupled to mass spectrometry (GC-MS). The study of molecular model showed that 95% was degraded at 20 kGy dose rate. Irradiation at 15 kGy of absorbed dose showed some cracking in petrol hydrocarbons, however with higher doses it was observed polymerization and low efficiency of cracking. It was observed that the sulfur compounds from diesel and petroleum was efficiently reduced. The applied doses of 15 kGy and 30 kGy were the most efficient on desulfurization of petroleum, and for diesel the highest variation was observed with 30 kGy and 50 kGy of absorbed dose. The distillation and chromatographic separation using an open column with palladium chloride as stationary phase showed a preferential separation of organic sulfur compounds in petroleum.

A 5-membered INOC cycloadduct 84 was employed to prepare alcohol 91, which was transformed into several cyclopent-2-enone derivatives 94-96. / By using intramolecular nitrile oxide-alkene cycloaddition (INOC) as the kep step to construct hydroxylated carbocycles, gabosine F was synthesized for the first time from L-arabinose. Hence, theoretically, gabosine B, which is the enantiomer of gabosine F, can also be synthesized from D-arabinose by the same synthetic strategy. / In this thesis, the background information on the construction of carbocycles from carbohydrates via intramolecular 1,3-dipolar cycloaddition is presented. A review regarding the syntheses of gabosine B and cocaine are also descibed. / Starting with D-ribose, INAC of nitrones 113, 129, and 140, bearing an alpha/beta-unsaturated ester as the dipolarophile was studied. The INAC endo-cycloadduct 141 (cycloheptane) was converted into natural cocaine sucessfully, together with cocaine analogues 162,169,170,173,175, and 177. / The regioselectivity of intramolecular nitrone-alkene cycloaddition (INAC) was studied. The INAC of hept-6-enose nitrone 98, with a 3,4- trans-pentylidene acetal as the only blocking group, afforded endo-cycloadduct 97 (cycloheptane) exclusively. This result concluded that the regiospecific outcome of this INAC reaction is due to the present of the 3,4-trans-pentylidene acetal blocking group. / To investigate the regioselectivity in INAC of hex-5-enose with a 2,3- trans-pentylidene acetal blocking group, nitrones 178 and 195 were prepared from D-mannitol. endo-Cycloadducts (cyclohexanes) were afforded exclusively. / So, King Ho. / Adviser: Kung Ming Tony Shing. / Source: Dissertation Abstracts International, Volume: 73-06, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 165-171). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.