175,990 research outputs found
Anaerobic treatment of slaughterhouse wastewater using the UASB process
No full textEffluents from the slaughterhouses, meat and poultry industries are heavily polluted and contain a high concentration of biodegradable organic materials. Therefore, the pollution capacity of these industries is high. Most of these industries discharge their effluents to a sewer or a watercourse.In order to comply with water pollution control standards and to reduce costs on sewer surcharges, these industries have to apply an adequate treatment of their effluents.Physical and chemical treatment methods as well as the conventional biological treatment processes are frequently applied in the treatment of these effluents. A combination of the methods are required where the effluent is to be discharged to surface waters, since no single treatment method will provide sufficient effluent.In the last decade, the high rate anaerobic wastewater treatment systems have become a good alternative for conventional aerobic as well as anaerobic biological treatment methods. The high rate anaerobic treatment systems were initially developed for the treatment of highly soluble low and medium strength wastewaters. These systems provided only a partial treatment of complex wastewaters containing a high fraction of suspended solids such as slaughterhouse wastewater.Investigations have shifted towards the application of high rate systems like the upflow anaerobic sludge blanket (UASB) for the complete treatment of agro-industrial wastewaters which are more difficult to handle, because they contain relatively high concentrations of suspended solids, i.e. complex wastewaters.Presently, the UASB system is the most widely applied high rate anaerobic system for complete treatment of such complex wastes.This thesis focuses on the question whether, and under which operationa conditions and environmental circumstances a one stage UASB mesophilic anaerobic treatment system is suitable for a complete treatment of slaughterhouse wastewater in practice.The feasibility of using the upflow flocculent anaerobic sludge blanket (UASB) process for a one stage anaerobic treatment of unsettled complex slaughterhouse wastewater, which contains approximately 50% of coarse insoluble COD, was investigated (Chapter 2). The continuous experiments were performed in a 25.3 m 3UASB pilot-plant which was operated under semi-continuous conditions, viz. with a varying organic load over day and nighttime (i.e. high organic load during the daytime and with low organic load at night) and with weekend feed interruptions. The UASB pilot-plant was operated at a temperature of 30° C. In order to assess the feasibility of the process under conditions of lower temperatures the temperature was reduced to 20°C, 20 weeks after the start-up of the reactor.The data indicated that the system can satisfactorily handle organic loads up to 3.5 kg COD m -3day -1at a liquid retention time of 8 h at temperatures as low as 20°C. Temporary shock loads up to 7.5 kg COD m -3day -1during the day time at a liquid retention time of 5 h were accommodated satisfactorily provided such a shock load was followed by a period of low loading, e.g. at night.A significant discrepancy was found between the treatment efficiency in terms of COD reduction and to the lower calculated percentage of supplied COD total converted into methane-COD. This difference indicated that a significant portion of the achieved COD reduction was due to the accumulation of non- or slowly biodegradable substrate ingredients in the reactor. No differentiations could be made between the different types of substrate ingredients that accummulated in the reactor because the accumulated sludge was not characterized. However, a part of the accumulated substrate was converted to CH 4 in periods of feed interruptions.In Chapter 3 the feasibility of the upflow granular anaerobic sludge blanket process for a one-stage anaerobic treatment of slaughterhouse wastewater was investigated. The experiments were performed under semi-continuous operational conditions viz. continuous feeding at a constant organic load (24 h day) during the working days but with weekend feed interruptions, and process temperatures of 30°C and 20°C. Under a stable operation of the system, i.e. at a maximum COD reduction and a high conversion of COD into methane, the optimal loading rates that could be applied were 11 kg COD m -3day -1and 7 kg COD m -3day -1at 30°C and at 20°C respectively.The system was less effective in the removal of coarse suspended solids, compared to the removal of the colloidal and soluble fractions from the slaughterhouse wastewater.The data obtained in these investigations indicate that imposed prolonged loadings exceed the optimal loading rates, lead to deterioration of the specific methanogenic activity of the sludge, due to the accumulation of colloidal and soluble fractions of the wastewater in the sludge bed. Therefore, it was concluded that the system stability strongly depends on the processes involved in the removal of the colloidal and soluble compounds from the wastewater and their conversion into methane. As the predominant - non-biological-mechanisms underlying the elimination of these wastewaters pollutants were considered the entrapment and the adsorption mechanisms. The effect of these mechanisms on the rate of the liquefaction of the accumulated substrate - which is the required first step in their conversion into methane - were discussed.The different pollutant fractions of the wastewater, viz. the coarse suspended solids, the colloidal and the soluble compounds affect the performance of the UASB reactors because of the different mechanisms involved in the removal of these substrate ingredients and their subsequent conversion into methane. Therefore, these mechanisms were investigated in more detail. The results of these investigations are presented in Chapter 4. The experiments were performed in a one-stage flocculent sludge UASB-reactor under continuous operational conditions viz. continuous feeding at a constant organic load during 24 h a day and 7 days a week.The COD removal efficiency of the UASB reactor exceeded the COD removal efficiency as expected from the observed CH 4 production, indicating once again that non-biological mechanisms are involved. Two different non-biological mechanisms were distinguished in the removal of substrate ingredients from the wastewater. The entrapment mechanism prevailed in the elimination of coarse suspended solids, while mainly adsorption mechanisms are involved in the removal of colloidal and the soluble fractions of the wastewater.A continued accumulation of substrate ingredients in the reactor ultimately will become detrimental for the stability of the anaerobic treatment process, as it leads to sludge flotation and consequently could result in a complete loss of the active biomass from the reactor.After having demonstrated the principle feasibility of the upflow anaerobic sludge blanket (UASB) process for a one-stage anaerobic treatment of the slaughterhouse wastewater, we decided to assess the maximum possible extent of anaerobic degradation of the soluble, colloidal and coarse suspended solids fractions of the slaughterhouse wastewater (Chapter 5). In this way we intended to get a better insight in the real limitations of the system. All the experiments were performed at process temperatures of 30°C and 20°C, using membrane filtered wastewater (wastewater mf ), paper filtered wastewater (wastewater pf ) and total wastewater. The experiments were performed in a recirculated batch digester system with granular sludge. The experiments with the coarse suspended solids separated from the wastewater were performed with granular sludge as well as with flocculent sludge using conventional batch-fed stirred digesters. The maximum biodegrability percentages (i.e. conversion into methane) found at 30°C were 75% for wastewater mf , 61% for wastewater pf and 67% for wastewater total while at 20°C these values were 72%, 49% and 51% respectively. The maximum biodegrability of the coarse suspended solids fraction of the waste amounts to 50% at 30°C and 45% at 20°C.The mechanisms involved in the removal of the soluble and colloidal fractions of the slaughterhouse wastewater were thoroughly studied and elucidated. The data obtained in these experiments indicate that the prevailing mechanism in the removal of the soluble but especially also the colloidal fraction of the wastewater is an adsorption mechanism. The relatively high degree of adsorption of the colloidal fraction of the wastewater to the surface of the sludge, in combination with its high fat content, will deteriorate the specific methanogenic activity of the sludge. The adsorption of the colloidal materials will ultimately result in an enclosure of the granular sludge bacterial matter with a film of increasing thickness, and perhaps also density, which increasingly will hamper the supply of substrate to the bacteria present in the grains. The deterioration effect of fats towards the methanogenic activity of the sludge was explained on the basis of the inhibitory effect of the long-chain fatty acids of the neutral fats.As the extent of adsorption is very similar at lower and higher temperatures, but the rate of liquefaction of adsorbed compounds drops significantly at decreasing temperatures, it will be evident that the process can withstand considerably lower loading rates at 20°C as compared to 30°C.Therefore, it is concluded that the rate of liquefaction of the adsorbed insoluble colloidal fraction of the wastewater is the controlling factor with respect to loading potentials of the process and consequently that the temperature is the factor of predominant importance
Anaerobic treatment of slaughterhouse wastewater using the UASB process
No full textEffluents from the slaughterhouses, meat and poultry industries are heavily polluted and contain a high concentration of biodegradable organic materials. Therefore, the pollution capacity of these industries is high. Most of these industries discharge their effluents to a sewer or a watercourse.In order to comply with water pollution control standards and to reduce costs on sewer surcharges, these industries have to apply an adequate treatment of their effluents.Physical and chemical treatment methods as well as the conventional biological treatment processes are frequently applied in the treatment of these effluents. A combination of the methods are required where the effluent is to be discharged to surface waters, since no single treatment method will provide sufficient effluent.In the last decade, the high rate anaerobic wastewater treatment systems have become a good alternative for conventional aerobic as well as anaerobic biological treatment methods. The high rate anaerobic treatment systems were initially developed for the treatment of highly soluble low and medium strength wastewaters. These systems provided only a partial treatment of complex wastewaters containing a high fraction of suspended solids such as slaughterhouse wastewater.Investigations have shifted towards the application of high rate systems like the upflow anaerobic sludge blanket (UASB) for the complete treatment of agro-industrial wastewaters which are more difficult to handle, because they contain relatively high concentrations of suspended solids, i.e. complex wastewaters.Presently, the UASB system is the most widely applied high rate anaerobic system for complete treatment of such complex wastes.This thesis focuses on the question whether, and under which operationa conditions and environmental circumstances a one stage UASB mesophilic anaerobic treatment system is suitable for a complete treatment of slaughterhouse wastewater in practice.The feasibility of using the upflow flocculent anaerobic sludge blanket (UASB) process for a one stage anaerobic treatment of unsettled complex slaughterhouse wastewater, which contains approximately 50% of coarse insoluble COD, was investigated (Chapter 2). The continuous experiments were performed in a 25.3 m 3UASB pilot-plant which was operated under semi-continuous conditions, viz. with a varying organic load over day and nighttime (i.e. high organic load during the daytime and with low organic load at night) and with weekend feed interruptions. The UASB pilot-plant was operated at a temperature of 30° C. In order to assess the feasibility of the process under conditions of lower temperatures the temperature was reduced to 20°C, 20 weeks after the start-up of the reactor.The data indicated that the system can satisfactorily handle organic loads up to 3.5 kg COD m -3day -1at a liquid retention time of 8 h at temperatures as low as 20°C. Temporary shock loads up to 7.5 kg COD m -3day -1during the day time at a liquid retention time of 5 h were accommodated satisfactorily provided such a shock load was followed by a period of low loading, e.g. at night.A significant discrepancy was found between the treatment efficiency in terms of COD reduction and to the lower calculated percentage of supplied COD total converted into methane-COD. This difference indicated that a significant portion of the achieved COD reduction was due to the accumulation of non- or slowly biodegradable substrate ingredients in the reactor. No differentiations could be made between the different types of substrate ingredients that accummulated in the reactor because the accumulated sludge was not characterized. However, a part of the accumulated substrate was converted to CH 4 in periods of feed interruptions.In Chapter 3 the feasibility of the upflow granular anaerobic sludge blanket process for a one-stage anaerobic treatment of slaughterhouse wastewater was investigated. The experiments were performed under semi-continuous operational conditions viz. continuous feeding at a constant organic load (24 h day) during the working days but with weekend feed interruptions, and process temperatures of 30°C and 20°C. Under a stable operation of the system, i.e. at a maximum COD reduction and a high conversion of COD into methane, the optimal loading rates that could be applied were 11 kg COD m -3day -1and 7 kg COD m -3day -1at 30°C and at 20°C respectively.The system was less effective in the removal of coarse suspended solids, compared to the removal of the colloidal and soluble fractions from the slaughterhouse wastewater.The data obtained in these investigations indicate that imposed prolonged loadings exceed the optimal loading rates, lead to deterioration of the specific methanogenic activity of the sludge, due to the accumulation of colloidal and soluble fractions of the wastewater in the sludge bed. Therefore, it was concluded that the system stability strongly depends on the processes involved in the removal of the colloidal and soluble compounds from the wastewater and their conversion into methane. As the predominant - non-biological-mechanisms underlying the elimination of these wastewaters pollutants were considered the entrapment and the adsorption mechanisms. The effect of these mechanisms on the rate of the liquefaction of the accumulated substrate - which is the required first step in their conversion into methane - were discussed.The different pollutant fractions of the wastewater, viz. the coarse suspended solids, the colloidal and the soluble compounds affect the performance of the UASB reactors because of the different mechanisms involved in the removal of these substrate ingredients and their subsequent conversion into methane. Therefore, these mechanisms were investigated in more detail. The results of these investigations are presented in Chapter 4. The experiments were performed in a one-stage flocculent sludge UASB-reactor under continuous operational conditions viz. continuous feeding at a constant organic load during 24 h a day and 7 days a week.The COD removal efficiency of the UASB reactor exceeded the COD removal efficiency as expected from the observed CH 4 production, indicating once again that non-biological mechanisms are involved. Two different non-biological mechanisms were distinguished in the removal of substrate ingredients from the wastewater. The entrapment mechanism prevailed in the elimination of coarse suspended solids, while mainly adsorption mechanisms are involved in the removal of colloidal and the soluble fractions of the wastewater.A continued accumulation of substrate ingredients in the reactor ultimately will become detrimental for the stability of the anaerobic treatment process, as it leads to sludge flotation and consequently could result in a complete loss of the active biomass from the reactor.After having demonstrated the principle feasibility of the upflow anaerobic sludge blanket (UASB) process for a one-stage anaerobic treatment of the slaughterhouse wastewater, we decided to assess the maximum possible extent of anaerobic degradation of the soluble, colloidal and coarse suspended solids fractions of the slaughterhouse wastewater (Chapter 5). In this way we intended to get a better insight in the real limitations of the system. All the experiments were performed at process temperatures of 30°C and 20°C, using membrane filtered wastewater (wastewater mf ), paper filtered wastewater (wastewater pf ) and total wastewater. The experiments were performed in a recirculated batch digester system with granular sludge. The experiments with the coarse suspended solids separated from the wastewater were performed with granular sludge as well as with flocculent sludge using conventional batch-fed stirred digesters. The maximum biodegrability percentages (i.e. conversion into methane) found at 30°C were 75% for wastewater mf , 61% for wastewater pf and 67% for wastewater total while at 20°C these values were 72%, 49% and 51% respectively. The maximum biodegrability of the coarse suspended solids fraction of the waste amounts to 50% at 30°C and 45% at 20°C.The mechanisms involved in the removal of the soluble and colloidal fractions of the slaughterhouse wastewater were thoroughly studied and elucidated. The data obtained in these experiments indicate that the prevailing mechanism in the removal of the soluble but especially also the colloidal fraction of the wastewater is an adsorption mechanism. The relatively high degree of adsorption of the colloidal fraction of the wastewater to the surface of the sludge, in combination with its high fat content, will deteriorate the specific methanogenic activity of the sludge. The adsorption of the colloidal materials will ultimately result in an enclosure of the granular sludge bacterial matter with a film of increasing thickness, and perhaps also density, which increasingly will hamper the supply of substrate to the bacteria present in the grains. The deterioration effect of fats towards the methanogenic activity of the sludge was explained on the basis of the inhibitory effect of the long-chain fatty acids of the neutral fats.As the extent of adsorption is very similar at lower and higher temperatures, but the rate of liquefaction of adsorbed compounds drops significantly at decreasing temperatures, it will be evident that the process can withstand considerably lower loading rates at 20°C as compared to 30°C.Therefore, it is concluded that the rate of liquefaction of the adsorbed insoluble colloidal fraction of the wastewater is the controlling factor with respect to loading potentials of the process and consequently that the temperature is the factor of predominant importance
Experiencing the armed struggle : the Soweto generation and after
No full textIncludes bibliographical references (p. 354-369).This study explores the experiences of the rank-and-file soldiers of Umkhonto we Sizwe and the Azanian People's Liberation Anny. Extensive interviews by the author and other researchers reveal the voices of the soldiers themselves. The African National Congress and Pan African Congress archives at the University of the Western Cape and the University of Fort Hare supplement and verify these oral testimonies, as do some published sources. Most previously published materials about the armed struggle against apartheid have already focused on diplomacy, strategy and tactics, operations, leadership, and human rights abuses to the neglect of the soldiers' actual experiences. This study complements these with significant new oral history materials from the Soweto generation of soldiers and their successors. When dealing with MK, many authors have documented issues of the camp structure in Angola, and operations inside South Africa, so much of this detail is only addressed briefly, leaving space to explore the soldiers' experiences. In the case of APLA, very little has been written on its history, and more detail is provided on these subjects. This study therefore deals with the soldiers' politicisation and motivation for joining the armed struggle, their experiences in leaving South Africa and training in exile, the crises in exile which limited their effectiveness for a time, their return to fight in South Africa, and their difficulties in the "new" South Africa. These materials reveal that vast problems remain facing these veterans of the struggle against apartheid, and that they have the potential, if properly supported and employed, to contribute substantially to the development of present day South Africa. Conversely, if their neglect continues, they also have the potential to bring vast harm to the country. Further use of the investigative tools of oral history, especially if extended to the former soldiers' vernacular languages, is necessary to augment the history of South Africa, and these soldiers' contributions
Intrathecal Drug Delivery Systems Survey: Trends in Utilization in Pain Practice [Corrigendum]
No full textAbd-Sayed A, Fiala K, Weisbein J, et al. J Pain Res. 2022;15:1305–1314.
The authors have advised there is an error in the author list on page 1305. The author name “Alaa Abd-Sayed” should read “Alaa Abd-Elsayed”.
The authors apologize for this error
Tenuipalpus granati Sayed 1946
No full textTenuipalpus granati Sayed 1946 (Figs 82–88) Tenuipalpus granati Sayed 1946: 100; Wainstein 1960: 247; Livshitz & Mitrofanov 1967: 31; Meyer (Smith) 1979: 70. Tenuipalpus orchidarum Sayed 1942: 96. Misidentification. Diagnosis. Dorsum with irregular striae but almost smooth in the Turkish specimens, longitudinal laterally on opisthosoma, venter with mainly transverse striae. Dorsal opisthosomal setae c 1, f 2 present; setae d 1 and e 1 absent. Venter with two pairs of 4 a setae. Spermatheca is a long, slender tube, terminating in small bulb. Female. Dimensions: Length of body excluding gnathosoma 240–254; width 139–141, infracapitulum covered by anterior prodorsal projection; Legs: I 119–122; II 105–109; III 100–107; IV 105–108; setae: v 2 6–7; sc 1 8–11; sc 2 30–35; c 1 8–13; c 3 10–18; d 3 8–10; e 3 11 –19; f 2 17–26; f 3 15–24; h 1 122–147; h 2 14–19. Body oval. Dorsum (Fig. 82). Anterior prodorsal projection deeply notched medially forming pair of pointed lobes medially. Prodorsum with an angulate anterolateral margin, just anterior to setae sc 2; opisthosoma gradually narrowing posteriorly, with two large lateral pores. Prodorsum and opisthosoma with scattered longitudinal to diagonal striae. Dorsal body setae slender, lanceolate, and weakly serrate. Venter (Figs 83–84). Venter striate. Metapodosoma with one pair of 3 a and two pairs of flagellate 4 a. Striation pattern of ventral and genital shields mostly transverse, with some longitudinal striae laterad in genital region. Pair of aggenital setae slightly longer than two pairs of genital setae, reaching to or slightly passing bases of genital setae; two pairs of pseudanal setae. Ventral setae smooth. Genital setae transversely aligned. Spermatheca a long, slender tube; terminating in a small bulb. Gnathosoma (Fig. 85). Infracapitulum covered by anterior projection, reaching to middle of femur I. Palp three-segmented, tarsus with a eupathidium, seta on tibia with at least two serrations; distal segment almost half length of second segment. Legs (Figs 86–88). Setae and solenidia (included in counts) on segments of legs I–IV: coxae 2 - 2 - 1 - 1, trochanters 1 - 1-2 - 1, femora 4 - 4 - 2 - 1, genua 2 - 2 -0-0, tibiae 5 - 5 - 3 - 3, and tarsi 9 (ω)- 9 (ω)- 5 - 5. Leg chaetotaxy as follows: trochanters I, II, IV v’; tr III l’, v ’; femora I-II d, v, bv”, l’; fe III d, ev ’; fe IV ev ’; genua I-II l’, l”; ge III-IV nude; tibiae I–II d, l’, l”, v’, v”; ti III–IV d, v’, v”; tarsus I–II u’, u”, p’, p” tc’, tc”, ft’, ft”, ω; ta III–IV u’, u”, tc’, tc”, ft’. Dorsal setae on femora I–III lanceolate and serrate, absent on genua I–II. Material examined. 1 female from Vitis vinifera L. (Vitaceae), Salihli/Manisa, 10 September 1997, S. Çobanoğlu; 2 females from Vitis vinifera, Menemen Çavuşköy /Izmir, 04–05 September 1997, (Collector; S. Çobanoğlu. Deposited at University of Ankara). Distribution. Azerbaijan, Cyprus, Egypt, Georgia, Greece, India, Iran, Kazakhstan, Ukraine (Sayed 1946; Pritchard & Baker 1958; Wainstein 1960; Dosse 1971; Sadana & Gupta 1984; Hatzinikolis 1986 a; Khanjani et al. 2013 b).Published as part of Çobanoğlu, Sultan, Ueckermann, Edward Albert & Sağlam, Hayriye Didem, 2016, The Tenuipalpidae of Turkey, with a key to species (Acari: Trombidiformes), pp. 151-186 in Zootaxa 4097 (2) on pages 177-178, DOI: 10.11646/zootaxa.4097.2.1, http://zenodo.org/record/27102
On Functions Preserving Convergence of Series in Fuzzy n-Normed Spaces
No full textThe purpose of this paper is to introduce finite convergence sequences and
functions preserving convergence of series in fuzzy n-normed spaces
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Discursive design thinking: The role of explicit knowledge in creative architectural design reasoning
No full textThe main hypothesis investigated in this paper is based upon the suggestion that the discursive reasoning in architecture supported by an explicit knowledge of spatial configurations can enhance both design productivity and the intelligibility of design solutions The study consists of an examination of an architect's performance while solving intuitively a well-defined problem followed by an analysis of the spatial structure of their design solutions One group of architects will attempt to solve the design problem logically, rationalizing their design decisions by implementing their explicit knowledge of spatial configurations The other group will use an implicit form of such knowledge arising from their architectural education to reason about their design acts An integrated model of protocol analysis combining linkography and macroscopic coding is used to analyze the design processes The resulting design outcomes will be evaluated quantitatively in terms of their spatial configurations The analysis appears to show that an explicit knowledge of the rules of spatial configurations. as possessed by the first group of architects can partially enhance their function-driven Judgment producing permeable and well-structured spaces These findings are particularly significant as they imply that an explicit rather than an implicit knowledge of the fundamental rules that make a layout possible can lead to a considerable improvement in both the design process and product This suggests that by externalizing the design knowledge and restructuring it in a design model, creative thought can efficiently be evolved and stimulate
Studies on the biosynthesis of the various subunits of neomycins
No full textThis thesis is concerned with the elucidation of the mechanism of the formation of the various subunits of neomycins B and C. The first target was to study the epimerization process at C-5 of D-glucose during its incorporation into the neosamine B ring of neomycin B. For this purpose an unambiguous, new method for the preparation of [5-3H] glucose was developed and using this labelled species it was found that most of the tritium (90% ) from the 5-position of the glucose was lost during conversion into the neosamine B moiety. These results suggest that the epimeric centre at C-5 of the neosamine B ring is produced through an enolization process involving a carbonyl group at either C-4 or C-6. The involvement of C-4 was eliminated by demonstrating that the 3H at C-4 of [3,4-3H] D-glucose was incorporated intact into neosamine B. On the bases of these results a reaction sequence for the epimerization process is suggested. The second problem investigated in this thesis is regarding the pathway for the biosynthesis of the 2-deoxystreptamine ring of neomycins. Four compounds expected to be involved in this pathway were prepared and used for the incorporation experiments. These compounds are [6-3H]6-deoxy-5-keto-D-glucose, [5,6-3H]6-deoxy-D-glucose, 2-deoxyscylloinosose and viboquercitol. The results show that 6-deoxysugar derivatives are incorporated into 2-deoxystreptamine suggests that the elimination of the unwanted C-6 hydroxyl group of D-glucose occurs prior to or during the cyclization process. In order to shed further light on the biosynthesis of 2-deoxystreptamine, we investigated whether C-3, C-4 and C-5 are involved in this process by using [3-3H]; [4-3H]; [5-3H] D-glucose. The results from these experiments showed that the 3H atoms at C-4 and C-5 of D-glucose are lost during the biosynthesis of 2-deoxystreptamine. On the other hand, the C-3 tritium of D-glucose was retained at C-5 of 2-deoxystreptamine. The loss of C-4 tritium of D-glucose implies that C-4 of D-glucose must be involved in the biosynthesis of 2-deoxystreptamine either by conversion into a carbonyl group which is necessary for the enhancement of the acidity of C-5 hydrogen during the elimination of the unwanted -OH group at C-6 or formation of a C-4 - C-5 endiol intermediate. The elimination of the C-5 tritium of D-glucose is in accord with the notion that C-5 of D-glucose is converted to the C-3 amino group of 2-deoxystreptamine via a carbonyl intermediate. The above results were used to suggest detailed reaction sequence for the biosynthesis of 2-deoxystreptamine. (D73650/87)</p
‘Tenderstem’ Broccoli for Export Markets: an Analysis Study on the AgroFood Company
No full textDecision case, horticulture, agriculture economics, broccoli production, protected vegetable production, Agricultural Finance, Crop Production/Industries, Production Economics,
- …
