Abstract: Eugenol is a major volatile constituent of clove essential oil obtained throughN hydrodistillation of mainly Eugenia caryophyllata (=Syzygium aromaticum) buds and leaves. It is a remarkably versatile molecule incorporated as a functional ingredient in numerous products and has found application in the pharmaceutical, agricultural, fragrance, flavour, cosmetic and various other industries. Its vast range of pharmacological activities has been well-researched and includes antimicrobial, anti-inflammatory, analgesic, anti-oxidant and anticancer activities, amongst others. In addition, it is widely used in agricultural applications to protect foods from micro-organisms during storage, which might have an effect on human health, and as a pesticide and fumigant. As a functional ingredient, it is included in many dental preparations and it has also been shown to enhance skin permeation of various drugs. Eugenol is considered safe as a food additive but due to the wide range of different applications, extensive use and availability of clove oil, it is pertinent to discuss the general toxicity with special reference to contact dermatitis. This review summarises the pharmacological, agricultural and other applications of eugenol with specific emphasis on mechanism of action as well as toxicity data.

Abstract The increasing awareness of the depletion of fossil fuel resources and the environmental benefits of biodiesel fuel has made it more attractive in recent times. The cost of biodiesel, however, is the major hurdle to its commercialization in comparison to petroleum-based diesel fuel. The high cost is primarily due to the raw material, mostly neat vegetable oil. Used cooking oil is one of the economical sources for biodiesel production. However, the products formed during frying, can affect the transesterification reaction and the biodiesel properties. This paper attempts to review various technological methods of biodiesel production from used cooking oil. The analytical methods for high quality biodiesel fuel from used cooking oil like GC, TLC, HPLC, GPC and TGA have also been summarized in this paper. In addition, the specifications provided by different countries are presented. The fuel properties of biodiesel fuel from used cooking oil were also reviewed and compared with those of conventional diesel fuel.

Abstract The contribution of the volatile constituents to the overall antimicrobial efficacy of the medicinal plant Tarchonanthus camphoratus was considered, where different extraction techniques were applied to yield four fractions. These comprised of the essential oil prepared by hydrodistillation, non-volatile constituents prepared by extraction of plant material remaining in the distilling apparatus (having no or negligible volatile constituents), and extracts prepared from fresh and dried plant material having both volatile and non-volatile constituents. The antimicrobial activities of the non-volatile and volatile fractions of T. camphoratus singularly (MIC method) and in combination (isobologram ratio method) demonstrated that the volatile constituents play an integral role in the total antimicrobial efficacy of the plant. The MIC values for the essential oils of T. camphoratus ranged from 1.5 to 16.0 mg/ml depending on the pathogen studied. With the exception of studies on Klebsiella pneumoniae, the non-volatile fraction devoid of volatile constituents displayed higher antimicrobial efficacies (2.0–4.0 mg/ml). When the volatile and non-volatile fractions were combined, increased efficacy was mostly noted with the dried plant material mostly showing a higher antimicrobially-active profile. Synergistic interactions were further validated by the isobologram studies on the combination of non-volatiles with essential oil.

Background: Oil yield from avocado fruit may be influenced by fruit pre-treatment and extraction method. Unripe and ripe avocado fruit pieces were deep-frozen at −20 ◦C and either freeze-dried or oven-dried (80 ◦C). Oil yield from these samples was determined after extraction with hexane and supercritical carbon dioxide (SC-CO2). The fruit samples were examined using scanning electron microscopy before and after oil extraction. RESULTS: Average oil yield from ripe fruit (freeze-dried and oven-dried combined) was 72 g kg−1 higher than from unripe fruit for SC-CO2 extracts and 61 g kg−1 higher for hexane extracts. This may be due to enzymatic degradation of parenchyma cell walls during ripening, thus making the oil more available for extraction. Freezedried samples had a mean oil yield 55 g kg−1 greater than oven-dried samples for SC-CO2 extracts and 31 g kg−1 higher for hexane extracts. However, oil yields from ripe fruit (freeze-dried and oven-dried) subjected to hexane extraction were not significantly different. All hexane extracts combined had a mean oil yield 93 g kg−1 higher than SC-CO2 extracts. CONCLUSION: SC-CO2 may be more selective and may create paths of least resistance through the plant material. Hexane, on the other hand, is less selective and permeates the whole plant material, leading to more complete extraction and higher oil yields under the experimental conditions.

Heteropyxis natalensis (Heteropyxidaceae) is traditionally used to treat respiratory disorders, and as a decongestant and antimicrobial agent. The seasonal variation of the hydrodistilled essential oil was investigated. Three trees in the Johannesburg Botanical Garden (Gauteng) indicated similar chemical profiles with fluctuation in the levels of the two major constituents (1,8-cineole and limonene). Little variation between the antimicrobial activity of seasonally collected samples was documented, with standard deviations of ±0.3 to ±3.3 depending on the pathogen studied. Moderate antimicrobial activity (3.0–16.0 mg/ml) was noted for most pathogens tested with Cryptococcus neoformans exhibiting the highest sensitivity (2.0–3.0 mg/ml). The chemogeographical variation of the oil composition from five of the seven distinct localities studied all contains 1,8-cineole and limonene as major constituents. The antimicrobial study of these samples indicated little variability between localities (standard deviation of ±0.5 to ±3.8). As observed in the seasonal variation study, C. neoformans displayed the highest sensitivity (0.5–2.0 mg/ml). One oil sample (Lagalametse), was distinctly different both chemically and microbiologically.

This thesis dea1s with mode11ing of formation damage resu1ting from invading s01ids, particu1ar1y in re1ation to water injection schemes Where10wconcentration micron and sub-micron s01ids are concerned. Ear1ier investigations were considered inadequate for study of formation damagedue to partic1e invasion in manyrespects such as the nature of damage, depth of damage characteristics and the inf1uence of various parameters on the damagedata. A porosity mode1(in 1inear and radia1 forms) based on mass ba1ance of partic1es and a pore size distribution based 3Dcapi1lary network model are presented. The network model uses various particle capture criteria including a newprobability criteria to model particle retention. The resu1ts from rock core based f10wtests are presented and ana1yzed. The f10w tests were conducted on 00x25 •4na-dia. sandstone cores of permeabi1ity range of 250 to 1000 md using 1-15 ppm concentrations of O-3~ a1umina partic1es at flow-rates of 0.45-1.00 mils up to 150 hours equiva1ent to over 40000 core pore v01umes. The experimental invastigations showthe importance of depth of damageand 10ng duration experiments on formation damagedata studies. Experimental permeability shows si.mp1e semi-1og dec1ine with gross f10w ve1ocity. serious occurs even for the 10w concentration systems. The iBIporta.nce of core preparation is stressed, where the use of brok.en faced cores is shown to be more appropriate for conducting partic1e inv . . as1.onexperuaents as comparedto the conventiona1 sa.wn-facedcores. Both the porosity mode1and the network.mode1predictions are shownto agree reasonab1y we11with the experimenta1 data.

This thesis examines visual representations of English country life and labour in the period 1870 to 1905 in relation to contemporary beliets in the centrality of the rural world to conceptions of national identity and'Englishness'. Centering upon an analysis of oil and watercolour paintings, but also interrogating prints, posters and photographs, the thesis examines the ways in which the production and consumption of images of rural lite in the period addressed and articulated widespread elite cultural concerns over a complex range of social issues, including purported racial degeneration, growing class conflict, and the checking of British imperial ambitions. Divided thematically into five distinct yet interlinked chapters, the thesis investigates firstly the stylistic evolutions in the painting of rural life across the period, and the connections made between particular visual languages and notions of a'national' school of art. The second chapter focuses upon an assessment of pictorial representations of the farmworker, looking in particular at the ways in which visual descriptions of rural labourer's bodies explored ideas of racial identity and national character. Chapters Three and Four look in turn at the representation of the country village and of field sports, the chapters both individually and cumulatively charting the relationship between visual culture and the generation of ideas around community,d eferencea nd social cohesion. The final section addressesth e portrayal of agricultural work, looking specifically at the themes of ploughing and mechanisationa, nd the cultural negotiationo f signso f modernity in the countryside. Treating visual images not as historically-transcendant objects, but as significant elements within a particular and specific material culture, the thesis compares visual images to other contemporary accounts of rural life, including those offered in novels, poetry and agricultural journalism. It views paintings of rural life and labour as critical spaces in which contemporary elite ideologies were actively articulated and contested, describing paintings of the rural world not as sites of settled meaning, but rather as formative elements of a dynamic process that continually re-worked and reevaluated evolving conceptions of rurality and'Englishness'.

No description available.

No description available.

No description available.