Faculty of Applied Sciences

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12 Polyphenol oxidases : the future toward global sustainability
(De Gruyter, 2024-04-08) Harun-Ur-Rashid, Mohammad; Krishna, Suresh Babu Naidu; Golla, Narasimha; Bin Imran, Abu
Polyphenol oxidases (PPOs) are enzymes that catalyze the oxidation of phenolic compounds, which are abundant in many plant-based foods. PPOs are crucial in postharvest losses and food waste, especially in developing countries with underdeveloped food supply chains. There has been a growing interest in utilizing PPOs for sustainable food production and preservation, modifying phenolic compounds to develop new food products, detecting phenolic compounds in various products, and utilizing bioremediation, agriculture, biotechnology, and waste management techniques to promote global sustainability. These advances have the potential to provide effective solutions toward achieving a more sustainable future. The most promising application of PPOs for achieving global sustainability is their use as a natural preservative to prolong the shelf life of fresh produce. They can be used to produce novel food products, such as functional foods and nutraceuticals, by modifying the phenolic compounds. The approach can add value to the food industry by creating new products with health benefits and reducing waste. PPOs can be used in bioremediation processes to degrade phenolic compounds found in industrial wastewater and produce natural antioxidants from food waste, promoting circular economy principles. They can also contribute to sustainable agriculture by increasing plant resistance to pests and diseases, reducing synthetic pesticides and herbicides, and improving crop yields. Overall, PPOs have a promising role in creating a more sustainable environment. This chapter thoroughly examines the latest developments in utilizing PPOs for sustainable food production and waste management. It emphasizes the enzyme's potential in natural preservation, novel food production, bioremediation, and sustainable agriculture. Additionally, the authors explore the wide range of applications for PPOs, such as biosensors, bioremediation, agriculture, and biotechnology.
12th International Conference on Sustainable Waste Management
(2022-12-02) Nibedita, Nath; Subhendu, Chakraborthy; Narsimha, Golla; Adam, Jamila Khatoon; Krishna, Suresh Babu Naidu
Today, nanotechnology generates a significant amount of interest among researchers as a result of the vast array of applications it provides for addressing various aspects of the eco-system. Additionally, it enables researchers to traverse the boundaries of a more specialised area of study than an already well-established one. It is an interdisciplinary field of study that focuses on the production and manipulation of nanoscale materials via scaling down the particle size scale from micrometres to nanometers (1–100 nm). They provide excellent options in the fields of health, industry, and medicine as they present a new vision for the treatment of medical conditions thanks to the fact that the particle size may be reduced, which gives them a distinct prospective characteristic. Researchers continue to be interested in finding new uses for metal nanoparticles (NPs) as the field of nanotechnology advances since these particles display distinctive properties. The public is interested in several different types of metal nanoparticles, including silver NPs. Synthesized silver nanoparticles (AgNPs) can be used in a wide variety of contexts, such as spectrally selective coatings for the absorption of solar energy, as intercalation material for electrical batteries, as optical receptors, as catalysts in chemical processes, and so on. Antibacterial and antifungal properties are only two of the biological uses of silver nanoparticles that have been the subject of much research. AgNPs are known to be cytotoxic to both normal and cancer cells in mammals, and the modalities of interactions of AgNPs have been examined in a variety of prokaryotic and eukaryotic systems. AgNPs are known to be cytotoxic to both normal and cancer cells in humans. The cytotoxic effects of silver ions have been seen and documented in a variety of cell lines. Silver nanoparticles have become important research topics due to the numerous applications they have in the fields of industry, agriculture, and biomedicine, as well as their excellent anti-bacterial, anti-fungal, anti-oxidant, anti-inflammatory, anti-viral, anti-coagulant, and photo-catalytic properties due to their chemical stability and good biocompatibility. The most important focus of this review is on recent advancements and trends in the field of AgNPs for use in biomedical applications. Keywords: Antimicrobial, silver nanoparticles, synthesis, biomedical applications, nanotechnology
2-(4-Bromoanilino)-6-(4-chlorophenyl)-5-methoxycarbonyl-4- methyl-3,6-dihydropyrimidin-1-ium chloride
(International Union of Crystallography, 2013-03-09) Venugopala, Katharigatta Narayanaswamy; Nayak, Susanta K.; Odhav, Bharti
In the title molecular salt, C19H18BrClN3O2+·Cl-, the dihedral angles between the pyrimidine ring and the chlorobenzene and bromobenzene rings are 72.4 (2) and 45.5 (2)°, respectively. The dihedral angle between the chlorobenzene and bromobenzene rings is 27.5 (2)°. The conformation of the molecule is stabilized by an intramolecular C-H...O interaction. In the crystal, the anion and cation are linked by an N-H...Cl hydrogen bond. Pairs of weak C-H...O and C-H...Cl hydrogen bonds form inversion dimers. Further N-H...Cl hydrogen bonds form R21(6) motifs and link the dimers into chains along [101]. Br...Cl short contacts [3.482 (2) Å] interlink the hydrogen-bonded chains along the b-axis direction.
{2-[(1,3-Benzothiazol-2-yl)methoxy]-5- bromophenyl}(phenyl)methanone
(International Union of Crystallography, 2013) Venugopala, Katharigatta Narayanaswamy; Nayak, Susanta K.; Odhav, Bharti
In the title compound, C21H14BrNO2S, the dihedral angle between the planes of the benzothiazole and phenylmethanone groups is 63.4 (2)°. In the crystal, pairs of C-H...N hydrogen bonds link the molecules to form inversion dimers, which are further linked by C-H...O interactions into chains along the c axis. C-H...[pi] and [pi]-[pi] interactions [centroid-centroid distance = 3.863 (1) Å] further stabilize the molecular assembly.
{2-[(1,3-Benzothiazol-2-yl)methoxy]-5-bromophenyl}(phenyl)methanone
(International Union of Crystallography, 2014-05-21) Venugopala, Katharigatta Narayanaswamy; Nayak, Susanta K.; Odhav, Bharti
In the title compound, C21H14BrNO2S, the dihedral angle between the planes of the benzothiazole and phenylmethanone groups is 63.4 (2)°. In the crystal, pairs of C-H...N hydrogen bonds link the molecules to form inversion dimers, which are further linked by C-H...O interactions into chains along the c axis. C-H...[pi] and [pi]-[pi] interactions [centroid-centroid distance = 3.863 (1) Å] further stabilize the molecular assembly.
4-Dihydroxy-3-(indol-2-)-yl-quinoline via substantial methodology-fisher indole synthesis
(Heterocyclic Letters, 2016) Pitchai, P.; Nepolraj, A.; Sathiyaseelan, M.; Gengan, Robert Moonsamy
Fisher indole methodology, a simple application was used to generate indole as a substitution on the quinoline ring. Conventional heating and microwave irradiation was compared. The ease of work up procedure, reduced time and moreover the high yield is exceptional however microwave irradiation presented more advantages.
57Fe Emission Mossbauer study on Gd3Ga5O12 implanted with dilute 57Mn
(Springer International Publishing Switzerland, 2016) Krastev, P. B.; Gunnlaugsson, H. P.; Nomura, K.; Adoons, V.; Gerami, A. M.; Johnston, K.; Ncube, M.; Mantovan, R.; Masenda, Hilary; Matveyev, Y. A.; Mølholt, Torben Esmann; Unzueta, I.; Bharuth-Ram, Krish; Gíslason, H.; Langouche, G.; Naidoo, D.; Ólafsson, S.
57Fe emission M¨ossbauer spectroscopy has been applied to study the lattice location and properties of Fe in gadolinium gallium garnet Gd3Ga5O12 (GGG) single crystals in the temperature interval 300 – 563 K within the extremely dilute (<10−4 at.%) regime following the implantation of 57Mn (T1/2 = 1.5 min.) at ISOLDE/CERN. These results are compared with earlier M¨ossbauer spectroscopy study of Fe-doped gadolinium gallium garnet Gd3Ga5O12(GGG), with implantation fluences between 8×1015 and 6×1016 atoms cm−2. Three Fe components are observed in the emission M¨ossbauer spectra: (i) high spin Fe2+ located at damage sites due to the implantation process, (ii) high spin Fe3+ at substitu-tional tetrahedral Ga sites, and (iii) interstitial Fe, probably due to the recoil imparted on the daughter 57∗Fe nucleus in the β− decay of 57Mn. In contrast to high fluence 57Fe implanta-tion studies the Fe3+ ions are found to prefer the tetrahedral Ga site over the octahedral Ga site. No annealing stages are evident in the temperature range investigated. Despite the very low concentration, high-spin Fe3+ shows fast spin relaxation, presumably due to an indirect interaction between nearby gadolinium atoms.
7 Unlocking nature’s remediation arsenal : the role of polyphenol oxidases in efficient and eco-friendly industrial wastewater treatment
(De Gruyter, 2024-04-08) Nagarajan, Prithiviraj; Rajathy, Leena; Patil, Sharangouda J.; Golla, Narasimha; Krishna, Suresh Babu Naidu
Phenol and its derivatives have gained considerable attention recently due to their high toxicity, teratogenicity, and mutagenicity. Petroleum refinery wastewater is a significant source of phenolic compounds. However, conventional techniques used to treat these wastewaters have several drawbacks, such as incomplete or inefficient removal of phenols. In contrast, biocatalytic processes have garnered significant attention as they offer sustainable and effective removal of toxins, including phenols, from wastewater. Among various biocatalysts, polyphenol oxidases have emerged as major biocatalytic enzymes. These enzymes contain copper and catalyze the oxidation of specific phenolic substrates to quinones in the presence of molecular oxygen. Polyphenol oxidases have a wide range of applications. In the food industry, they are utilized for cocoa and tea production, enhancing coffee flavor and assessing food quality. In medicine, they find applications in treating phenylketonuria, Parkinson's disease, and leukemia. In environmental technology, they play a crucial role in removing phenolic pollutants from industrial wastewater. In the pharmaceutical industry, polyphenol oxidase-immobilized electrodes differentiate between morphine and codeine. This chapter provides comprehensive details about polyphenol oxidases' structure, biochemical properties, and applications, specifically focusing on their role in wastewater treatment.
AB initio studies of a pentacyclo-undecane cage lactam
(2003) Singh, Thishana
The purpose of this study is to utilize computational techniques in the determination of the mechanistic pathways for the one-pot conversion of a pentacyclo-undecane (PCU) dione 1.1 to a pentacyclo-undecane cage lactam 1.2.
Acceptance of a ready-to-use supplementary food by stable HIV-treated and HIV and tuberculosis (co-infected)-treated patients
(NISC (Pty) Ltd and Taylor & Francis, 2014) Pillay, K.; Siwela, M.; Feldman, F.J.; Amonsou, Eric Oscar; Mabaso, B.P.
Objectives: The objective of the study was to determine consumer acceptance and perceptions of a ready-to-use supplementary food (RUSF) by subjects treated for human immunodeficiency virus (HIV) and HIV and tuberculosis (co-infected subjects). Design: A cross-sectional study was conducted. Subjects: One hundred and thirty-nine stable HIV-treated and HIV and tuberculosis (co-infected)-treated patients participated in the study. Sixty-eight healthy subjects served as the control group. Setting: The setting was Northdale Hospital and Grey’s Hospital in Pietermaritzburg, KwaZulu-Natal. Outcome measures: Acceptance of the RUSF was assessed using a five-point facial hedonic scale by stable HIV-treated and HIV and tuberculosis (co-infected)-treated patients (n = 139) from Northdale Hospital and Grey’s Hospital in Pietermaritzburg, KwaZulu-Natal. Perceptions of the RUSF were determined through focus group discussions in which HIV-treated and HIV and tuberculosis (co-infected)-treated patients (n = 43) participated. Results: The overall acceptance of the RUSF was significantly associated with the health status of the subjects (p-value < 0.05). Overall, the product was liked by more than 90% of the HIV-treated and HIV and tuberculosis (co-infected)-treated individuals compared to 85% of the control group. More than 90% of the HIV-treated and HIV and tuberculosis (co-infected)-treated individuals liked the taste, compared to 87% of the control group. The colour and mouth feel were rated to be “good” by more than 80% of the HIV-treated and HIV and tuberculosis (co-infected)-treated group, compared to approximately 70% of the healthy group. Focus group discussions revealed that the subjects perceived the mouth feel of the RUSF to be “rough”, and that as a health supplement, the RUSF should be provided free of charge, or at a reasonable cost, at public health centres. Conclusion: The RUSF was found to be highly acceptable to stable HIV-treated and HIV and tuberculosis (co-infected)-treated subjects, although concern was raised about the mouth feel.
The accumulation of heavy metals by aquatic plants
(2003) Maharaj, Saroja; Moodley, Kandasamy Govindsamy; Southway-Ajulu, F. A.; Baijnath, Himansu
The pollution of water bodies by heavy metals is a serious threat to humanity. The technique known as phytoremediation is used to clean up these polluted water bodies. The accumulation of heavy metals by aquatic plants is a safer, . cheaper and friendlier manner of cleaning the environment. The aquatic plants -studied in this project are A.sessilis, P.stratiotes, R.steudelii and T.capensis. The accumulation of heavy metals in aquatic plants growing in waste water treatment ponds was investigated. The water, sludge and plants were collected from five maturation ponds at the Northern Waste Water Treatment Works, Sea Cow Lake, Durban. The samples were analysed for Zn, Mn, Cr, Ni, Pb and Cu using ICP-MS. In general it was found that the concentrations of the targeted metals were much lower in the water (0.002 to 0.109 mg/I) compared to sediment/sludge (44 to 1543mg/kg dry wt) and plants (0.4 to 2246 mg/kg dry wt). These results show that water released into the river from the final maturation pond has metal concentrations well below the maximum limits set by international environmental control bodies. It also shows that sediments act as good sinks for metals and that plants do uptake metals to a significant extent. Of the four plants investigated it was found that }t.sessi[ir (leaves, roots and stems) and }A.sessilis (roots and stems) are relatively good collectors of Mn and Cu respectively. These findings are described in the thesis. The concentration of heavy metals in the stems, leaves and roots of the three plants were compared to ascertain if there were differences in the ability of the plant at different parts of the plant to bioaccumulate the six heavy metals studied.
Active targeting of cancer cells using gemcitabine conjugated platinum nanoparticles
(2017) Odayar, Kriya; Odhav, Bharti; Mohanlall, Viresh
Nanotechnology is explained as the science of engineered materials and systems on a molecular scale. This innovation is currently used in a wide variety of applications which include using these nanoparticles as drug delivery vehicles. Such nanocarriers are relatively smaller than 100 nm in size with the ability to convey therapeutic drugs to a number of disease sites. Platinum-based nanoparticles have been extensively used in a number of applications namely catalysts, gas sensors, glucose sensors and cancer therapy. The properties of platinum nanoparticles (PtNP’s) typically depend on characteristics such as shape, particle size, elemental composition and structure, all of which can be manipulated and controlled in the fabrication process. Their unique size in the nanometer scale makes platinum nanoparticles an ideal candidate as targeted drug delivery vehicles. To target an anticancer drug to a diseased site is a distinctive feature of most studies, which aim to transfer an adequate dosage of the drug to cancer cells. Transport systems used as carriers of anticancer drugs offer numerous advantages, which include improved efficacy and a decrease in toxicity towards healthy cells when compared to standard drugs. The aim of this study was to determine the effect of platinum nanoparticles, gemcitabine and gemcitabine conjugated platinum nanoparticles (Hybrids) against cancer cells and healthy cells and to determine the mode of cell death and cell death pathways using flow cytometry. Platinum nanoparticles were synthesized via the reduction of hexachloroplatinic acid using sodium borohydride in the presence of capping agents. Synthesized platinum nanoparticles and the hybrids were characterized by observing peaks at 301 nm and 379 nm respectively using UV-visible spectroscopy. TEM images revealed that the PtNP’s and the conjugate compounds were spherical in shape with core sizes of 1.14 nm - 1.65 nm and 1.53 - 2.66 nm respectively. The bioactivity platinum nanoparticles, gemcitabine and the hybrids were investigated using MCF7 and Melanoma cancer cells at different concentrations from 0.10 to 100 µg/ml. Results indicated that conjugated nanoparticles induced the highest cell inhibition against both cell lines compared to gemcitabine and platinum nanoparticles. Bioactivity against PBMC (peripheral blood mononuclear) cells indicated that all three compounds show little or no effect towards the healthy cell line compared to the control. Melanoma cell line was used to determine the mode of cell death. Apoptosis was detected using Annexin V-FITC to detect membrane changes, JC-1 to detect a loss in mitochondrial membrane potential and caspase-3 assay kits. Results indicated that a significant amount of cell death was caused by cleavage of caspase-3. Nanoparticle drug delivery is an area that has shown significant promise in cancer treatment. Interaction of nanoparticles with human cells is an interesting topic for understanding toxicity and developing potential drug candidates. Imagine, something that is atleast or more than 80,000 times smaller than the edge of the ridge on a fingertip and unlocks a new wilderness into cancer research. Nanotechnology, known as the science of minute, is changing the approach to cancer and especially future diagnosis and treatment. Nanotechnology permits scientists to fabricate new apparatuses that are definitely smaller than cells, giving them the chance to attack tumor diseased cells. This innovation not just empowers practitioners to recognize malignancies prior but additionally holds the guarantee of halting cancer growth before it further develops. This progressive approach is so exact, specialists will in future be able to outline a unique treatment for an individual’s own restorative and hereditary profile. Researchers are designing nanoparticles that detect and destroy diseased cells and this optimistic innovation could be personalized for targeted drug delivery, enhanced imaging and ongoing affirmation of cancer cell death. The National Cancer Institute remains hopeful that facilitated development, nanotechnology will drastically change cancer treatment.
Activity coefficients at infinite dilution for ILs : methyltrioctylammonium cation and bis(trifluoromethylsulfonyl)imide or thiosalicylate anions using glc
(2009) Gwala, Nobuhle V.; Deenadayalu, Nirmala
The activity coefficients at infinite dilution ( γ13 ) were calculated for alkanes, alkenes, cycloalkanes, alkynes, ketones, alcohols and aromatic compounds from gas liquid chromatography (glc) measurements at three temperatures (303.15 and 313.15 and 323.15) K. The γ13 values were calculated from the retention data for two ionic liquids (ILs) with the same cation but different anions. The ionic liquids: [methyltrioctylammonium bis(trifluoromethylsulfonyl)imide and methyltrioctylammonium thiosalicylate] were used as the stationary phase. The γ13 data for methyltrioctylammonium thiosalicylate were higher than for methyltrioctylammonium bis(trifluoromethylsulfonyl)imide. For each temperature and each ionic liquid, γ13 values were determined for two columns and the average γ13 values were used for the calculation of the partial molar excess enthalpies at infinite dilution, H E 1 Δ , using the Gibbs-Helmholtz equation. Graphs of In γ13 vs 1/T were plotted to determine H E 1 Δ at T = 303.15 K. The selectivity, S12 , value for the hexane/benzene separation was calculated from the ratio of the avarage γ13 values to determine the suitability of the ILs as an entrainer for extractive distillation in the separation of aromatic and aliphatic compounds.The S12 values were also compared to the literature values for other ionic liquids. It was found that the longer chain alkyl group attached to the cation or anion gave lower S12 values. Both ILs have S12 values greater than one and in theory can be used as an entrainer for the hexane/ benzene separation. The capacities at infinite dilutions, k1 , were also calculated from the inverse of the avarage γ13 values for each IL at each temperature.
Adressing food and nutrition insecurity through the development and implementation of an agricultural and nutrition education programme on legumes for older farmers living in Mariannhill, KwaZulu-Natal, South Africa
(2020) Mkhize, Nkumbulo Xolile; Napier, Carin E.; Oldewage-Theron, Wilna; Duffy, Kevin Jan
Introduction Food and nutrition security can be influenced by various external and internal factors that contribute to a compromised wellbeing status amongst older farmers who are considered as a vulnerable group. This group faces diverse socio-economic and health challenges within an evolving food system. The complexity of this challenge persistently requires multisectoral intervention programmes, as reflected in the nature of this study. Aim and Objectives The aim of the study was to determine the levels of and address the food intake and nutrition insecurity status of elderly farmers. The main objective was to address the challenges that compromised the health of selected previously non-legume producing farmers by encouraging legume production and consumption amongst them. The findings of the study informed the proposal of appropriate strategies to develop an intervention programme intended to educate the identified elderly farmers and to promote their dietary diversification by means of legume production and consumption. Methodology The study employed a cross-sectional design. A baseline study was conducted that aimed at examining variable relationships using a mixed methods approach involving both qualitative and quantitative data collection techniques. A sample of 112 elderly farmers participated in the baseline study, followed by a case-controlled intervention programme that included preand post-intervention surveys. The measuring instruments included socio-demographic as well as health and medical surveys to elicit data such as blood pressure, blood indices for glucose and cholesterol due to dietary intake, household food security, legume knowledge, legume acceptability and agricultural practices. The data informed the findings of both the baseline and the intervention phases of the study. The baseline study involved a sample of 112 elderly farmers, whereas the intervention study involved two case controls (n=103) that comprised an experimental group (EG: n=53) and a control group (CG: n=50). Data were obtained for both groups by analysing blood indices, dietary intake, yields of legume production (EG only) and legume acceptability levels using statistical analyses of variance, significance and trends of pre- and post-intervention surveys over two years. A follow-up survey (FU) was conducted six months after the conclusion of the intervention phase and involved only the EG (n=32), to assess the impact of the intervention programme on their dietary intake and farming practices. The follow-up study thus compared the intervention data of the farmers’ consumption and production patterns with data obtained postintervention. During this latter study, only dietary intake and production levels were measured. All the data were analysed using IBM Statistical Package for Social Sciences (SPSS), Food Finder software, the Mann-Whitney U test, Analysis of Variance (ANOVA) and T-tests for statistical frequencies, variances and correlations. Results In the baseline study, 79.5% of the participants were women. The mean age of the participants was 63.3 ± 8.2 years. A diverse legume consumption was not observed as indicated by a low legume food group diversity score (FGDS) for 0-9 varieties with a mean of 3.5 (SD ± 1.70). Legumes were the least (19.0%) preferred crop planted by the farmers prior to the study. In the intervention study, the majority of participants were also women (73.6% in the EG and 66.0% in the CG). Of the six varieties of legumes under study, red kidney beans was the most preferred (141.60 kg/ha-1 SD ± 162.11). There was a high significance (p=0.001) amongst the six legume varieties produced, which implies that some legumes had a higher yield than others. A comparison between the genders indicated that the women produced 81.70 kg/ha-1 (SD ± 77.95), while the men produced 33.63 kg/ha-1 (SD ± 166.40). The higher yields produced by the women were significant (p=0.011). Legume consumption improved for the EG because the intervention programme resulted in a significantly (p=0.000) increased dietary diversity score (DDS) of legume intake with a mean (±SD) FGDS from 2.4 (SD ± 1.35) to 5.7 (SD ± 2.56) and a mean (±SD) Dietary Diversity Score (DDS) from 8.59 ± 0.74 to 8.23 ± 1.11, while that of the CG was 3.0 (SD ± 1.82). According to the post-intervention survey, the blood results of the EG indicated nutrient improvement at the 5.0% significance level for blood glucose (p=0.038) and cholesterol (p=0.008). The blood glucose levels of the EG were statistically significant (p=0.037) when this group was compared with the CG in both the pre-intervention and post-intervention surveys. Trend analyses were conducted and compared between those men and women who participated throughout the study (i.e. participation from the baseline to the post-intervention surveys). It was found that cholesterol (p=0.033) and Systolic Blood Pressure (SBP) (p=0.013) were statistically significant when the genders were compared across all phases of the study. Data obtained for the EG in the Follow Up (FU) study six months after the intervention study indicated that the production of legumes had declined (71.8%). This was because the legume intake with a mean (±SD) FGDS of 3.0 ± 2.2 indicated a significant (p=0.000) drop from 5.7 (SD ± 2.56) with DDS from 8.23 (± 1.11) to 8.81 (± 0.47) at p=0.005 significance as determined by the FU survey. It was also found that limited marketing of legumes had occurred, which suggests that the sustainability of legume production and consumption post-intervention by the elderly farmers was a challenge. However, 100.0% of the farmers indicated that they intended to continue their production and consumption of legumes, provided that the constant supply of legumes did not cease. Conclusions Evidence was obtained that the intervention project positively impacted the production and consumption of legumes and that the elderly farmers thus diversified their dietary intake for the better during this phase of the study. However, further investigations need to be conducted to explain the decline in consumption and production in the post-intervention period if support for a healthier lifestyle amongst elderly farmers is to be sustained. The technology to produce legumes with high yields to address food insecurity through more appropriate consumption patterns also needs to be explored in greater depth. Because the two streams of knowledge transfer that involved hands-on training of elderly farmers improved legume production and consumption patterns, this study established a sound foundation on which future studies and intervention strategies for food security amongst vulnerable groups may be built.
Advances in synthesis of biodiesel via enzyme catalysis : Novel and sustainable approaches
(Elsevier, 2015-01) Singh, Bhaskar; Mutanda, Taurai; Permaul, Kugen; Bux, Faizal; Guldhe, Abhishek
Biodiesel, a renewable fuel has a great potential in fulﬁlling an ever-increasing transport fuel demand. The enzymatic conversion process of feedstock oil to biodiesel is greener when compared to the conventional approach of chemical conversion due to mild reaction conditions and less wastewater generation. Lipases obtained from various microbial sources have been widely applied as catalysts for the conversion of oil to biodiesel. Biodiesel and glycerol obtained by enzymatic conversion have shown a higher purity as compared to that obtained by other conversion techniques. Enzymatic conversion of oil to biodiesel is less energy intensive because of milder reaction conditions and fewer puriﬁcation steps involved in processing. Lipases, due to their catalytic efﬁciency and speciﬁcity, have emerged as a great tool for converting a wide range of feedstock oils to biodiesel. This manuscript presents an overview of the use of enzymatic conversion for making biodiesel production sustainable and environmentally-friendly. The constraints of enzymatic conversion are the high cost of the enzyme and its inhibition by alcohol and glycerol. The possible solutions to overcome these constraints are discussed. Recent advances to develop an effective process for enzymatic conversion of feedstock oils into biodiesel are critically evaluated. Prospective and challenges in scaling up of this technology are also discussed.
Algebraic and singularity properties of a class of generalisations of the Kummer–Schwarz equation
(Springerlink, 2016-09-28) Sinuvasan, R.; Tamizhmani, K. M.; Leach, P. G. L.
The Kummer–Schwarz Equation, 2y′y′′′−3y′′2=0, (the prime denotes differentiation with respect to the independent variable x) is well known from its connection to the Schwartzian Derivative and in its own right for its interesting properties in terms of symmetry and singularity. We examine a class of equations which are a natural generalisation of the Kummer–Schwarz Equation and find that the algebraic and singularity properties of this class of equations display an attractive set of patterns. We demonstrate that all members of this class are readily integrable.
The algebraic properties of the space- and time-dependent one-factor model of commodities
(Taylor and Fancis, 2016-06-06) Paliathanasis, Andronikos; Morris, Richard M.; Leach, P. G. L.
We consider the one-factor model of commodities for which the parameters of the model depend upon the stock price or on the time. For that model we study the existence of group-invariant transformations. When the parameters are constant, the one-factor model is maximally symmetric. That also holds for the time-dependent problem. However, in the case for which the parameters depend upon the stock price (space) the one-factor model looses the group invariants. For speciﬁc functional forms of the parameters the model admits other possible Lie algebras. In each case we determine the conditions which the parameters should satisfy in order for the equation to admit Lie point symmetries. Some applications are given and we show which should be the precise relation amongst the parameters of the model in order for the equation to be maximally symmetric. Finally we discuss some modiﬁcations of the initial conditions in the case of the space-dependent model. We do that by using geometric techniques.
Algebraic structures of generalised symmetries of n th-order scalar ordinary differential equations of maximal lie point symmetry
(Natural Sciences Publishing, 2015-05-01) Charalambous, K.; Leach, P. G. L.
We compute for the representative scalar ordinary differential equation of maximal point symmetry the generalised symmetries of order-one and two. We examine the Lie Brackets for the generalised symmetries and see that closure does not occur for generalised symmetries of order-two. Consequently all generalised symmetries up to the maximum order possible must be admitted.
Analysis of lubricating grease by ICP-OES : a case study on preparation methodology
(Asian Publication Corporation, 2016-01-30) Marume, Cathrine; Kumar, Bhajanthri Natesh; Redhi, Gan G.
The aim of this study was to develop simple, cost effective and reliable sample preparation methods for the analysis of lubricating grease samples. Direct dilution, microwave digestion and emulsification methods were designed and compared for the analysis of Ca, B, Al, Na, Mo, Zn and Ba with inductively coupled plasma optical emission spectroscopy (ICP-OES). The direct dilution method gave most inconsistent results in terms of percentage recovery. The optimized microwave digestion and emulsification methods compared well and showed good reliability in terms of sensitivity and selectivity. The calibration curves resulting from oil emulsion has no significant difference with that of aqueous emulsions, but the stability of the emulsified samples was very low. The limit of detection and limit of quantification values obtained from the microwave digestion method were very low and therefore it is superior amongst the three methods for the analysis of various lubricating grease samples.
Analysis of nanoscale ingredients in commercial food and cosmetic products by field-flow fractionation and single particle ICP-MS
(2020-09) Naidoo, Lyndon; Bisetty, Krishna; Kanchi, Suvardhan; Sabela, Myalowenkosi Innocent
There is a growing need to disclose the possible presence of nanostructures on the labels of commercial food and cosmetic products in South Africa. Synthetic amorphous silica (SiO2) and titanium dioxide (TiO2) are the two widely used nanoparticles (NPs) selected for this study. This work was undertaken in two stages. The first part deals with an analytical method developed for the separation and characterization of TiO2 NPs capped with poly(ethylene glycol) (PEG) as a potential reference material for sunscreen analysis. The second aspect of this work focuses on SiO2, a highly attractive biomaterial widely used as a food additive (E551) to improve the flow properties of powdered food ingredients. Also, modern computational methods were implemented in both case studies, to better understand the nanoparticulate interactions with the organic substrates at an atomistic and molecular level. For the cosmetics study, asymmetric flow field-flow fractionation (AF4) coupled online to multi-angle light scattering (MALS) and dynamic light scattering (DLS) detectors were employed to assess the geometry and size of the PEGylated TiO2 NPs in terms of the evaluated radius of gyration (rg) and hydrodynamic radius (rh). Single particle inductively coupled plasma mass spectrometry (spICP-MS) and transmission electron microscopy (TEM) were implemented to provide information on the core diameter (d) of the TiO2 particle. To overcome agglomeration, Monte Carlo simulations were employed in this study to assess the effectiveness of PEG capped onto spherically constructed TiO2 anatase nanoclusters by systematically performing a series of adsorption studies. For PEG-TiO2 NPs, AF4-MALS-DLS reported rg and rh values of 28.7 nm and 40.3 nm respectively, with the shape factor (rg/rh) values generally reported in the range of 0.7 to 0.8, indicative of spherical particle geometry. SpICP-MS and TEM obtained complementary measurements of d = 32.0 nm and d = 38.4 nm, respectively. The computational modelling results demonstrated the strong binding affinity of PEG as a capping agent to TiO2, exhibiting stabilisation of TiO2 NPs in aqueous medium. Finally, the developed AF4-MALS-DLS method was applied to two commercial SPF 50 sunscreens, exhibiting promising separation and detection efficiency. These findings can contribute to regulatory measures in line with the South African National Nanotechnology Strategy for the cosmetics industry. With regards to the food application study, a multivariate method was developed for the detection and characterization of SiO2 particles also based on AF4-MALS-DLS. This analytical approach attempts to address the fate and the presence of nanoparticulate SiO2 additives (E551) in food products. The experimental design using SiO2 NP standards resulted in the following optimum conditions of the system: crossflow, 0.8 ml/min; injection time, 5 min and sonication time, 60 min. It was observed that the average geometric diameters (Dgeo) for SiO2 NPs in three selected commercial coffee creamers (A, B and C) detected by AF4-MALS were 286.7 nm, 129.8 nm and 190.7 nm respectively. Similar trends for the coffee creamers were observed for the hydrodynamic diameter (Dh) measurements using AF4-DLS i.e. 301.5 nm, 141.3 nm and 197.8 nm respectively. The rg/rh values were reported ranging from 0.7 to 0.8, indicative of spherical particle geometry. Also, the electrostatic interactions between SiO2 NPs and glucose/water mixtures, as evaluated by Monte Carlo simulations, revealed O-interactions dominating over the flat amorphous SiO2 surface. The strongest interaction observed (around - 239 kcal/mol) for the SiO2-water/glucose mixture demonstrates the hydrophilic nature of SiO2 NPs. The findings in both case studies provide fundamental information to improve the understanding of nanoparticulate interactions with additives and paves the way for the labelling of cosmetic and food products that potentially exhibit nanomaterials in complex matrices.