Ultrasonic- and microwave-assisted extraction of curcuminoids and cyclodextrin complexes of curcumin from C. domestica Val.

This study investigates the isolation of curcuminoids from Curcuma domestica Val. using ultrasonic-assisted extraction (UAE), microwave-assisted extraction (MAE) compared with conventional cold solvent extraction method and the use of inclusion complexation of curcumin with methyl-?-cyclodextrin (Mß-CD) for improving their solubility. The extractions were optimized by determining the content of three curcuminoid markers, namely curcumin (C), demethoxycurcumin (DMC) and bisdemethoxycurcumin (BDMC). The extraction efficiencies were compared in terms of extraction time, sample through-put and solvent consumption. The optimized parameters for UAE of curcuminoids were extraction amplitude of 100, particle size of 0.30-0.60 mm, extraction time of 20 min, extraction solvent volume of 10 mL and extraction temperature of 60°C. Meanwhile, the relative recoveries (RRs) for aqueous extraction were in the range of 91.59-98.99%, 89.79- 94.95% and 89.33-94.77% for C, DMC and BDMC, respectively. Although UAE using methanol resulted in a slightly higher extraction yield and shorter extraction time compared to those using water, both methods showed similar pattern of results. Despite these, water is cost effective, safe and environmentally friendly. These advantages of aqueous solvent can be used as a yard stick to substitute organic solvents for UAE of curcuminoids from C. domestica. At maximum set energy, the MAE optimum extraction parameters were particle size of 0.30-0.60 mm, extraction time of 3 min, extraction solvent volume of 10 mL and extraction temperature of 60°C with RRs of 92.48-99.44%, 90.58-97.43% and 90.03-96.07% for C, DMC and BDMC, respectively. Both UAE and MAE applications showed remarkable improvements in terms of extraction time, solvent consumption, extraction yield and the quality of extracts compared to conventional cold solvent extractions method. However, as compared to UAE, the optimized MAE application was better in term of quantity of curcuminoids. MAE is also simpler, faster, more efficient approach and allows the possibility of simultaneous multiple extractions. The inclusion complex formed using Mß-CD with the application of MAE was more stable than that with UAE based on the stability constant (KC) values of 213.08 M-1 and 515.19 M-1, for UAE and MAE, respectively. Results from characterization of the inclusion complex with scanning electron microscope showed that co-precipitation method was best for UAE while all of the mixing methods can be used for the inclusion complexation with MAE application. The kneading and co-precipitation methods were found to be the best for the inclusion complexation between turmeric rhizome oleoresins and Mß- CD in UAE, while all of the mixing methods were found to be suitable for inclusion complexation of turmeric rhizome oleoresins with Mß-CD in MAE as indicated by Fourier transform infrared spectroscop

Phytoremediation of Heavy Metals Spiked Soil by Polyscias fruticose

This study was to assess the phytoremediation potential of Polyscias fruticose in the removal of heavy metals from spiked soil. P. fruticose cuttings were transplanted then grown on 2.00 kg soil spiked with several heavy metals in polyethylene bags. The experiment was conducted for 300 days and concentrations of heavy metals in plant and soil over the growth period were determined. Appreciable concentrations of heavy metals in P. fruticose parts were obtained. The indices used to show the ease of heavy metals uptake and translocation indicated that Co, Cr, Mn, Ni and Pb displayed the greatest ease of absorption while Zn, Fe and Cu were accumulated in the root but not translocated to the shoot. The results obtained shows that this study pioneered the use of P. fruticose in the phytoremediation of several heavy metals spiked soil at a greenhouse level

Ultrasonic-assisted extraction of curcumin complexed with methyl-beta-cyclodextrin

Turmeric flavour is important in Asian cuisine; however, the production of turmeric-based ingredient with the current method of extraction of turmeric oleoresin is very laborious, time consuming and consumes large amount of solvent, coupled with limited solubility in aqueous solution, which limits its application to food system. The extract was optimised by determining the content of three marker curcuminoid compounds, namely, curcumin (C), demethoxycurcumin (DMC) and bisdemethoxycurcumin (BDMC). The optimised extraction parameters for ultrasonic-assisted extraction (UAE) with aqueous extraction solvent for curcuminoids were amplitude of 100, particle size of 0.30–0.60 mm, extraction time of 20 min, extraction solvent volume of 10 mL and extraction temperature of 60 °C. The applications showed remarkable improvements in terms of reduced extraction time, solvent consumption, extraction yield and the quality of extracts. The turmeric oleoresin was successfully solubilised in aqueous solution by forming inclusion complex with methyl-ß-cyclodextrin (Mß-CD). Phase solubility studies used curcumin as a marker compounds to represent turmeric oleoresin. In the presence of Mß-CD, the curcumin was enhanced. Result from characterisation of inclusion complexes with Fourier transform infrared (FTIR) spectrometry indicates that all the mixing methods were found to be suitable for encapsulation. However, scanning electron microscopy (SEM) shows a drastic change in particle sizes, indicating a formation of a new solid phase in kneading method, implying it as the best mixing method

South-West Latvia Couronian Flat Burial Field Grave Goods in the Middle Iron Age

Lai gan reģionā attiecīgā laika posma atklāto un arheoloģiski pētīto kapulauku skaits ir pietiekošs, lai veiktu dziļākus pētījumus, tomēr 5. – 8. gs. kuršu kapu inventāts ir samērā maz aplūkots. Zinātniskajā literatūrā un publikācījās lielākoties sniegts tikai ieskats, bet ne tēmas padziļināts izklāsts. Bakalaura darba mērķis ir aplūkot un analizēt vienu no vidējā dzelzs likmeta kuršiem raksturīgajām apbedīšanas tradīcijām – mirušajiem līdzi doto kapa inventāru. Noskaidrot kāds kapa piedevas ir bijušas izplatītas, kā arī ko tās liecina par sabiedrību, kas tās lietojusi. Iegūtie rezultāti galvenokārt balstās uz senlietu izpēti un to tipoloģizācijas rezultātā iegūto informāciju. Pētījuma rezultāti parāda attiecīgā laika posma kuršu kapu ineventāru, kas, atšķirdamies, no citu etnosu kapu inventāriem, ļauj aplūkotā reģiona apbedītos indivīdus pieskaitīt kuršu sabiedrībai. Atslēgas vārdi: kurši, kapu inventārs, vidējais dzelzs laikmetsAlthough there are enough Couronian graves of the Middle Iron Age which are archaeologically investigated, in the scientific literature or in publications there are no deeper studies about that period and culture grave goods. The aim of this bachelor work is to view and analyze one of the Middle Iron Age Cours burial traditions – gave goods to their deads. Find out what kind of grave good were the most popular and what do they tells about society which wear them. The results mainly are based on artefact research and information of their typology. The research results provide a summary overview of the Middle Iron Age Cours grave goods. Those artefacts, which are different from another society grave goods, allows us to add people, who use that type of items, to Cours. Keywords: Cours, grave goods, Middle Iron Ag

Scandinavians in archaeological material of Grobiņa and its surroundings in the 7th-9th century

Lai gan skandināvu 7. – 9. gs. pieminekļos ir notikusi plaša arheoloģiskā pētniecība, mazāka uzmanība ir pievērsta pētījumu rezultātu apkopošanai. Maģistra darba mērķis ir apkopot un analizēt informāciju par skandināvu materiālo un garīgo kultūru Grobiņā un tās apkārtnē 7. – 9. gs. un balstoties uz iegūto materiālu, noskaidrot skandināvu vietu un lomu Rietumlatvijā aplūkotajā periodā. Darbs sastāv no četrām nodaļām: 1. Skandināvu 7. – 9. gs. pieminekļu raksturojums un pētniecība Grobiņā un tās apkārtnē; 2. Skandināvu apbedīšanas tradīcijas Grobiņā un tās apkārtnē 7. – 9. gs.; 3. Kapu inventārs; 4. Grobiņas skandināvu kolonijas raksturojums. Iegūtie rezultāti parāda, ka skandināviem bijusi neatņemama loma Rietumlatvijas teritorijas un tur dzīvojošo vietējo sabiedrību attīstības vēsturē. Atslēgas vārdi: Grobiņa, skandināvi, vidējais un vēlais dzelzs laikmetsAlthough Scandinavian 7th – 9th century monuments have been extensive archaeologically investigated, less attention has been devoted to summarize research results. The aim of the master`s thesis is to summarize and analyze information about Scandinavian material and mental culture in Grobiņa and its surroundings and find out Scandinavian significance in Western Latvia in this period. Master`s thesis consists of four chapters: 1. Scandinavian 7th – 9th century monument character and investigation in Grobiņa and its surroundings; 2. Scandinavian burial rites in Grobiņa and its surroundings 7th – 9th century; 3. Grave goods; 4. Scandinavian colony character in Grobiņa. Research results shows that Scandinavians had integral role in Western Latvia territory and local society development. Keywords: Grobiņa, Scandinavians, Middle and Late Iron Ag

An assessment of the effectiveness of central bank sterilization on capital inflows in Nigeria

This paper assesses the monetary policy response of the Central Bank of Nigeria(CBN) to increases in capital inflows into Nigeria using monthly time series datafrom January 2009 to December 2017. It presents an econometric assessment of thedegree to which the CBN sterilizes net foreign assets (NFA) in response to the cap-ital flows, using Autoregressive Distributed Lag (ARDL) Bounds testing approach.The long run sterilization coefficient obtained suggests that the CBN successfullyoffset 95per cent of capital inflows in the period of analysis. Against the back-ground of rising financial instability in Nigeria, the study illustrates how steriliza-tion has not adequately tackled the major risks of capital inflows which resultedin asset price bubbles and bursts, equity capital inflows reversal, banking crisis,and currency depreciation which contributed, partly, to the economic recession in2016. The paper argues that effective policy response to capital inflows must ade-quately address the major downside risks of capital inflows in the short and mediumterms through some clearly defined capital flows management and macro-prudentialmeasures

Sulfur-Doped Binary Layered Metal Oxides Incorporated on Pomegranate Peel-Derived Activated Carbon for Removal of Heavy Metal Ions

In this study, a novel biomass adsorbent based on activated carbon incorporated with sulfur-based binary metal oxides layered nanoparticles (SML-AC), including sulfur (S2), manganese (Mn), and tin (Sn) oxide synthesized via the solvothermal method. The newly synthesized SML-AC was studied using FTIR, FESEM, EDX, and BET to determine its functional groups, surface morphology, and elemental composition. Hence, the BET was performed with an appropriate specific surface area for raw AC (356 m2·g−1) and modified AC-SML (195 m2·g−1). To prepare water samples for ICP-OES analysis, the suggested nanocomposite was used as an efficient adsorbent to remove lead (Pb2+), cadmium (Cd2+), chromium (Cr3+), and vanadium (V5+) from oil-rich regions. As the chemical structure of metal ions is influenced by solution pH, this parameter was considered experimentally, and pH 4, dosage 50 mg, and time 120 min were found to be the best with high capacity for all adsorbates. At different experimental conditions, the AC-SML provided a satisfactory adsorption capacity of 37.03–90.09 mg·g−1 for Cd2+, Pb2+, Cr3+, and V5+ ions. The adsorption experiment was explored, and the method was fitted with the Langmuir model (R2 = 0.99) as compared to the Freundlich model (R2 = 0.91). The kinetic models and free energy (<0.45 KJ·mol−1) parameters demonstrated that the adsorption rate is limited with pseudo-second order (R2 = 0.99) under the physical adsorption mechanism, respectively. Finally, the study demonstrated that the AC-SML nanocomposite is recyclable at least five times in the continuous adsorption–desorption of metal ions

Sulfur-Doped Binary Layered Metal Oxides Incorporated on Pomegranate Peel-Derived Activated Carbon for Removal of Heavy Metal Ions

In this study, a novel biomass adsorbent based on activated carbon incorporated with sulfur-based binary metal oxides layered nanoparticles (SML-AC), including sulfur (S2), manganese (Mn), and tin (Sn) oxide synthesized via the solvothermal method. The newly synthesized SML-AC was studied using FTIR, FESEM, EDX, and BET to determine its functional groups, surface morphology, and elemental composition. Hence, the BET was performed with an appropriate specific surface area for raw AC (356 m2·g−1) and modified AC-SML (195 m2·g−1). To prepare water samples for ICP-OES analysis, the suggested nanocomposite was used as an efficient adsorbent to remove lead (Pb2+), cadmium (Cd2+), chromium (Cr3+), and vanadium (V5+) from oil-rich regions. As the chemical structure of metal ions is influenced by solution pH, this parameter was considered experimentally, and pH 4, dosage 50 mg, and time 120 min were found to be the best with high capacity for all adsorbates. At different experimental conditions, the AC-SML provided a satisfactory adsorption capacity of 37.03–90.09 mg·g−1 for Cd2+, Pb2+, Cr3+, and V5+ ions. The adsorption experiment was explored, and the method was fitted with the Langmuir model (R2 = 0.99) as compared to the Freundlich model (R2 = 0.91). The kinetic models and free energy (−1) parameters demonstrated that the adsorption rate is limited with pseudo-second order (R2 = 0.99) under the physical adsorption mechanism, respectively. Finally, the study demonstrated that the AC-SML nanocomposite is recyclable at least five times in the continuous adsorption–desorption of metal ions

Equilibrium, kinetic and mechanism studies of Cu(II) and Cd(II) ions adsorption by modified chitosan beads

In this study, the Cu(II) and Cd(II) ions removal behavior of crosslinked chitosan beads grafted poly(methacrylamide) (abbreviated as crosslinked chitosan-g-PMAm) from single metal ion solutions was investigated. The modified chitosan beads presented a remarkable improvement in acid resistance. The batch experiments demonstrated that pH of solution played a significant role in adsorption. It was found that the adsorption of Cu(II) and Cd(II) were optimum at pH 4 and pH 5, respectively. The maximum adsorption capacities for Cu(II) and Cd(II) based on Langmuir equation were 140.9 mg g−1 and 178.6 mg g−1, respectively. Pseudo-second order gave a better fit for adsorption data with respect to linearity coefficients than pseudo-first order suggesting that chemisorption or electron transfer is the dominant mechanism of the metal ions onto crosslinked chitosan-g-PMAm. In addition, X-ray photoelectron spectroscopy (XPS) investigations revealed that adsorption of both metal ions took place on the surfaces of crosslinked chitosan-g-PMAm by chelation through C–NH2, C–O and C[dbnd]O groups. Overall, the modified chitosan has proved a promising adsorbent for removal of metal ions