Physiochemical properties of alkali treated kappa - carrageenan

Kappa (k)-carrageenan was extracted from the seaweed Kappaphycus alvarezii, grown in Fiji, using varying concentrations of potassium hydroxide (KOH) solution: 0.1 to 0.5 M. Increasing KOH concentration increased the yield of -carrageenan while the sulfate content, and the viscosity average molar mass decreased. -carrageenan solutions exhibited non-Newtonian fluid behavior. For the different alkali (0.1, 0.2, 0.3 & 0.5 M) treated -carrageenan, the critical gelling concentration was found to be 1.0, 0.8, 0.7 & 0.6 w/v % respectively at ambient temperature within 24 hrs. The activation energy of the viscous flow was found to decrease for the -carrageenan extracted with increasing alkali concentration. Young’s modulus was found to increase for the -carrageenan gels extracted with increasing alkali concentration up to 0. 3 M after which a sharp decline in gel strength was observed. The melting temperature determined from Differential Scanning Calorimetry increased for gels extracted with higher KOH concentration

In - vitro pH responsive drug release kinetics of alkali extracted carrageenan crosslinked genipin/chitosan matrices

In this study, carrageenan, a sulphated polysaccharide was extracted using KOH treatment of different concentrations (0, 0.1, 0.3 M) from the red marine algae, Kappaphycus alvarezii. The alkali played a vital role in the transformation of carrageenan to its Kappa (κ) form thus improving the gelling properties. The membranes were prepared by blending varying amounts of κcarrageenan (20-40 v/v % of the prepared solution) with the cross linked chitosan and genipin solutions. The model drug was loaded onto the films by “encapsulating” it between two layers of the pre-gel blend solution and vacuum dried. Drug release from the membranes was investigated in three different pH media (1.2, 4.5, and 6.8) and was measured by UV/Vis spectrophotometer. Carrageenan treated with different concentrations of KOH had an impact on the sulphate content and molecular weight. With increasing KOH concentration, the sulphate recovered was 17.13, 15.72 & 8.71 % and the molecular weight was determined to be 64.2, 49.5, 8.2 ( x 105 g/mol ) respectively. This affected the gelling behaviour and as a result had an effect on the drug release profile. Membranes containing κ-carrageenan treated with 0.3 M KOH showed faster release of the drug than the carrageenan treated with 0.1 M KOH. However, there was little difference seen at a higher pH (6.8). This confirms that the release is responsive to pH changes. The release kinetics has been analyzed using the Zero order, First Order kinetic model, Higuchi plot and the Korsmeyer-Peppas model

Change detection of a coastal woodland mangrove forest in Fiji by integration of remote sensing with spatial mapping

Mangroves play key ecological role in structuring the availability of coastal resources. The current study was focused on change detection in a large mangrove patch located in Votua area of the Ba province in Fiji. Globally, the mangrove population continues to decline with the changes in climatic conditions and anthropo-genic activities. Baseline information through wetland maps and time series change are essential references for the development of effective mangrove management plans. These maps reveal the status of the resource over a period of time and the impacts from anthropogenic activities. Remote sensing techniques were integrated with geographic information system tools for mapping and detecting temporal change over a period of 20 years. Remotely sensed imagery data from Landsat satellite was sourced from the year 1999 to 2018 for this investigation. The mapping analysis of temporal changes in mangrove forests was carried using the versatile ArcGIS and ENVI software. The pilot change detection analysis revealed a small but important change in the mangrove patch over these years. Landward creep of mangroves was also detected. The outcomes of this study serve as baseline and conservation information for the development and implementation of effective management plans for one of Fiji’s largest mangrove patches

Climate Change Adaptation on Small Island States: An Assessment of Limits and Constraints

From MDPI via Jisc Publications RouterHistory: accepted 2021-05-11, pub-electronic 2021-05-31Publication status: PublishedSmall Island States (SIDS) are among the nations most exposed to climate change (CC) and are characterised by a high degree of vulnerability. Their unique nature means there is a need for more studies focused on the limits to CC adaptation on such fragile nations, particularly regarding their problems and constraints. This paper addressed a perceived need for research into the limitations of adaptation on SIDS, focusing on the many unique restrictions. To this end, the study identified and described the adaptation limits they have by using a review of the literature and an analysis of case studies from a sample of five SIDS in the Caribbean and Pacific regions (Barbados, Trinidad and Tobago, Cook Islands, Fiji, Solomon Islands and Tonga). This research’s findings showed that an adaptable SIDS is characterised by awareness of various values, appreciation and understanding of a diversity of impacts and vulnerabilities, and acceptance of certain losses through change. The implications of this paper are two-fold. It explains why island nations continue to suffer from the impacts of CC and suggest some of the means via which adequate policies may support SIDS in their efforts to cope with the threats associated with a changing climate. This study concluded that, despite the technological and ecological limits (hard limits) affecting natural systems, adaptation to CC is limited by such complex forces and societal factors (soft limits) that more adequate adaptation strategies could overcome

κ-carrageenan, genipin and chitosan cross - linked composites for drug release in simulated gastrointestinal fluids

κ-carrageenan was extracted from the red sea algae, Kappaphycus alvarezii using 0.1 and 0.3 M KOH. Blends for drug release were prepared by mixing varying amounts (20, 30 and 40 v/v %) of κ-carrageenan with chitosan and cross-linked with genipin. The optimal genipin concentration for the blend was determined by AFM and swelling studies. FT-IR showed that κ-carrageenan was immiscible with chitosan and hence mostly physical crosslinking had occurred. Swelling and drug release investigated in simulated gastrointestinal fluid (pH of 1.2, 4.5, 6.8) showed similar trends and were responsive to the ionic composition, pH of the media, and the amount of κ-carrageenan in the blend. Blends containing increasing amounts of κ-carrageenan, treated with 0.3 M KOH showed increased and faster drug release. The bio polymeric membranes were responsive to stimuli for the drug release and serves as a possible oral delivery route for Quetiapine fumarate

Threats posed by Asian subterranean termites in the Fiji Islands and their potential controls: a review

Termites belong to the infraorder Isoptera, which contains almost 3,000 described species worldwide. These social insects cause substantial damage globally leading to billions of dollars of losses annually. Damage can occur to timber, wooden goods, paper, cotton, certain plastics, trees and many crops. Consequently, termite control and management is a major sector in the global pest-control industry. However, economic losses due to termite damage have not been quantified in the Fiji Islands to date. A review of published literature was conducted to assess the geographic range of Asian subterranean termites that occur in the Fiji Islands and to identify existing and potential control measures. The most common termite species that is known to cause millions of dollars of damage each year in the Fiji Islands is Coptotermes gestroi. This species is currently controlled primarily using the chemical fipronil but integrated termite management is the preferred long-term solution. Other possible control methods include physical, cultural, chemical and biological options