Evaluation of crystalline amino acids as potent stimulatory chemoattractants for the slipper lobster Thenus orientalis

Intensive research on the effectiveness of chemoattractants has been widely explored to improve the feed qualities in expanding crustacean farming. Taste preferences in slipper lobster remained unknown despite their significant contribution to the lobster fisheries. Chemoattractants allow better performance in aquaculture species by increasing food attractiveness and palatability. Amino acids (AA) have been leading in previous research on crustacean feeding behavior. Given that slipper lobster possesses chemoreceptors to detect and orient towards food, this study investigated an approach to identify the AA with the most potent chemoattractant in eliciting a response from slipper lobster. Behavioral assays were performed to evaluate the responses of slipper lobster Thenus orientalis (carapace length, 52.34 ± 1.52 mm) on 15 crystalline AA and three derivatives of AA (DAA) at three concentrations between 10̄⁻¹ and 10⁻³ M as test substances (TS). Meretrix sp. extract was used as a positive control and clean filtered seawater as a negative control. The behavioral responses of 14 T. orientalis were evaluated based on their antennular flicking rate, third maxillipeds activity, and substrate probing by the pereiopods. T. orientalis responded to the solutions of single AA down to a concentration of 10⁻³ M, excluding histidine and serine. The behavioral activity displayed by T. orientalis increased with the TS concentrations. L-glutamic acid monosodium salt monohydrate, betaine, and glycine solutions elicited the most behavioral responses, whereas histidine exhibited the lowest behavioral responses. Conclusively, L-glutamic acid monosodium salt monohydrate, betaine, and glycine can be potential chemoattractants for T. orientalis

A polymeric microencapsulation approach for the simultaneous entrapment of multi-chemical entities

A novel drug delivery system consisting of drug-loaded microparticles encapsulated within larger hollow microcapsules had been devised. The novelty of this system is that microparticles can simultaneously be loaded with multiple drug types before being packed into a single microsphere. To demonstrate the feasibility of the proposed system, the system was fabricated through a modified two step O/W/O/W solvent emulsion technique. Poly (L-lactic acid) (PLLA) microparticles were first fabricated separately with two different flurophores, Coumarin 6 and Rhodamine 6G respectively. The flurophore-dye loaded PLLA microparticles were then mixed together and subsequently entrapped within degradable Poly [(D,L-lactide)-co-glycolide] (PLGA) microcapsules. SEM, Confocal and FTIR results had shown that fluorophore-loaded microparticles were successfully incorporated into a single hollow microcapsule. Ibuprofen was then loaded into the PLLA microparticles before encapsulation by the PLGA microcapsule to validate the capability of the system for drug hosting and delivery.Bachelor of Engineering (Materials Engineering

Water quality and phosphorus budget model for estimating the carrying capacity for fish rearing at Batang Ai reservoir, Lubok Antu, Sarawak

Fish cage culture in reservoir developed rapidly in order to meet the demand of fish for consumption. Phosphorus loading from fish cage culture activities could cause adverse impacts on the surrounding water bodies. Phosphorus budget model was used to estimate the maximum production from fish culture activities. The aims of this study were to determine the water quality and estimate the carrying capacity for fish rearing activities in Batang Ai reservoir, Sarawak. Carrying capacity of the reservoir was calculated based on Dillon and Rigler’s phosphorus budget model. Water quality parameters were measured at 5 stations, at subsurface, 10 m, and 20 m depths in October, November 2011 and April 2012 and at subsurface for station 6 in October, November 2011, and April 2012. Results show that chlorophyll a ranged from 0.38 to 6.02 mgm -3 , orthophosphate ranged from 0.01 to 0.27 mg/L, and total phosphorus from 0.03 to 0.24 mg/L. The higher concentration of orthophosphate and chlorophyll a at station 4 and 5 is due to sewage from longhouse community flushed by rain water in station 4 and effluent from fish culture in station 5. The carrying capacity was estimated at 5,948 and 10,641 tonnes per year based on the different phosphorus content in fish and feed. The estimated value was about 8 to 14 times higher than the current fish production at Batang Ai reservoir in 2011. Therefore, it is concluded that future expansion of cage culture activities in Batang Ai reservoir is still feasible

Evaluation of crystalline amino acids as potent stimulatory chemoattractants for the slipper lobster Thenus orientalis

Intensive research on the effectiveness of chemoattractants has been widely explored to improve the feed qualities in expanding crustacean farming. Taste preferences in slipper lobster remained unknown despite their significant contribution to the lobster fisheries. Chemoattractants allow better performance in aquaculture species by increasing food attractiveness and palatability. Amino acids (AA) have been leading in previous research on crustacean feeding behavior. Given that slipper lobster possesses chemoreceptors to detect and orient towards food, this study investigated an approach to identify the AA with the most potent chemoattractant in eliciting a response from slipper lobster. Behavioral assays were performed to evaluate the responses of slipper lobster Thenus orientalis (carapace length, 52.34 ± 1.52 mm) on 15 crystalline AA and three derivatives of AA (DAA) at three concentrations between 10−1 and 10−3 M as test substances (TS). Meretrix sp. extract was used as a positive control and clean filtered seawater as a negative control. The behavioral responses of 14 T. orientalis were evaluated based on their antennular flicking rate, third maxillipeds activity, and substrate probing by the pereiopods. T. orientalis responded to the solutions of single AA down to a concentration of 10−3 M, excluding histidine and serine. The behavioral activity displayed by T. orientalis increased with the TS concentrations. L-glutamic acid monosodium salt monohydrate, betaine, and glycine solutions elicited the most behavioral responses, whereas histidine exhibited the lowest behavioral responses. Conclusively, L-glutamic acid monosodium salt monohydrate, betaine, and glycine can be potential chemoattractants for T. orientalis

Microencapsulation of dye- and drug-loaded particles for imaging and controlled release of multiple drugs

A polymeric microcapsule that can house different drug-loaded particles using a simple emulsion packaging technique is presented. Compared to the neat microparticles, microcapsules simultaneously release multiple drugs in a sustained manner. These microcapsules could provide a means of controlling release of multiple drugs

Haptics in computer-mediated simulation: Training in vertebroplasty surgery

10.1177/1046878106291667Simulation and Gaming374438-45