The occurrence of tributyltin (TBT) is reported in the coastal waters of a few selected sites in Peninsular Malaysia. Water, bivalves and sediment samples collected were analysed specifically for TBT using sensitive analytical methods which involved a solvent extraction procedure with appropriate clean-up followed by graphite furnace atomic absorption spectrometric measurements. The levels of TBT in the seawater in unexposed areas were found in the range from <3.4 to 20 ng litre(-1) as compared to coastal areas with high boat and ship activities where TBT levels in seawater were generally above 30 ng litre(-1), with the highest level found at 281.8 ng litre(-1). TBT levels in the tissues of random cockle and soft-shell clam samples from local markets were found in the range from <0.5 to 3.7 ng g(-1) wet weight. The levels of TBT found in green mussel samples both from the market (23.5 ng g(-1) wet weight) and those from a mussel farm (14.2 ng g(-1) wet weight) indicate slight accumulation of TBT. In sediments, TBT levels were found ranging from <0.7 ng g(-1) dry weight in unexposed coastal sites to as high as 216.5 ng g(-1) dry weight for a site within a port area.
The effect of the oil-spill dispersant Corexit 9527 on egg-hatching rate of Macrobrachium rosenbergii (de Man) was studied by using an innovated flow-through bioassay technique. This bioassay method relies on the fact that M. rosenbergii fertilized eggs when detached from the mother prawn were able to hatch artificially. The flow-through system generated a stable and good water quality environment for hatching the eggs successfully. The Corexit 9527 had a pronounced effect on hatching rate of the M. rosenbergii eggs. In the control, the hatching rate of the eggs was 95.55% +/- 1.74%. However, it was reduced drastically with increasing concentrations of Corexit 9527. A 100% inhibition of egg hatchability was found when the level of Corexit 9527 was higher than 250 mg litre(-1). The EC(50) and the EC(95) values estimated by the probit method were 80.4 +/- 5.5 mg litre(-1) and 193.5 +/- 39.9 mg litre(-1) respectively (P = 0.05). The recommended safety level of Corexit 9527 for M. rosenbergii in Malaysian estuarine waters is below 40 mg litre(-1).
A study of heavy metal contents in freshwater snails from rice fields have been made. The results indicate that the levels of heavy metals, Pb, Cu, Zn and Cd, are low and within the permissible limit of Malaysian Food Regulations. The results can serve as background data for further reference.
Chrome azurol S immobilised on XAD-2 has been used in this study as a reagent phase for the development of an optical fibre Al(III) sensor. Using a kinetic approach, this sensor was able to give a linear response in the Al(III) concentration range of 1.3 x 10(-5)-2.0 x 10(-4) M with a limit of detection of 1.0 x 10(-4) M. The optimum responses were obtained at pH 6.0 and when the solution was stirred. The sensor response was found to have a repeatability and reproducibility of 1.6% and 5.8%, respectively. The results obtained for Al(III) determination in aqueous sample were in good agreement with those obtained using graphite furnace-atomic absorption spectrometry.
A description is given of cercarial chaetotaxy of two Centrocestinae (Heterophyidae, Opisthorchioidea) from Malaysia: Centrocestus formosanus and Centrocestus sp.--Comparison with cercarial chaetotaxy of taxonomically related groups indicates that 1. The chaetotaxy of the Centrocestinae agrees with that of other Opisthorchioidea, 2. There is an important difference between chaetotaxy of Centrocestinae and other Heterophyidae which suggest that the family is heterogeneous.
Increased primary plankton productivity was observed in a brackish water lagoon of Terengganu during the study period between January 1988 to December 1988. The lagoon is also the site for the fish cage culture activities of sea bass during the study period. An examination of water quality at the sampling stations during the study period indicated that both the organic and inorganic nutrients were high during the pre-monsoon period. The source of the nutrient in the lagoon was believed to be derived from the agro-based industrial effluents, fertilisers from paddy fields as well as untreated human and animal wastes. This coincided with the peak production of plankton in the surface waters of the brackish water lagoon. During this period both cultured and indigenous fish species were seen to suffer from oxygen asphyxiation (suffocation due to lack of oxygen). The primary productivity values ranged from 9 to 22 μg/L/h during the peak period while the microplankton species were composed of diatom, flagellates and dinoflagellates. Reduction in the primary productivity values were obtained with reduction in sallinity, specially during the peak monsoon months (November to March) corresponding to the Northeast monsoon period.
Marine biofouling causes problems to marine structure and obstructs condenser tubes in cooling systems which use sea water as the coolant. The main purpose of this study is to investigate the seasonal ecology of biofouling organisms such as the green mussel, Perna viridis, the dominant fouling species in the Eastern Johore Straits at the Senoko Power Station. The spawning time and its relationship with environmental conditions were studied. The physical, chemical and biological conditions of the sea at Senoko were monitored for a year. Settling slides were used to study the fouling succession in different monsoon seasons. The study showed that there were two main spawning peaks for the green mussel and that these peaks occurred during the intermonsoon months of November and April. These peaks were also correlated with the bimodal patterns for salinity, dissolved oxyen, bivalve veliger larval density and total plankton biomass of the Eastern Johore Strait water. Succession patterns were similar during the two monsoon seasons, however, the rate of fouling was probably greater during the southwest monsoon months. It is therefore advisable that the control or reduction of biofouling in Eastern Johore Strait should take into account the seasonal fluctuations and spawning of the fouling organisms.
Excessive sodium (Na+) intake in modern society has been associated with several chronic disorders such as hypertension. Several studies suggest that early life events can program physiological systems and lead to functional changes in adulthood. Therefore, we investigated behavioral and neuroendocrine responses under basal conditions and after 48 h of water deprivation in adult (60-day-old Wistar rats) male, Wistar rats originating from dams were offered only water or 0.15 mol/L NaCl during pregnancy and lactation. Early life salt exposure induced kidney damage, as shown by a higher number of ED-1 positive cells (macrophages/monocytes), increased daily urinary volume and Na+ excretion, blunted basal water intake and plasma oxytocin levels, and increased plasma corticosterone secretion. When challenged with water deprivation, animals exposed to 0.15 mol/L NaCl during early life showed impaired water intake, reduced salt preference ratio, and vasopressin (AVP) secretion. In summary, our data demonstrate that the perinatal exposure to excessive Na+ intake can induce kidney injury in adult offspring and significantly affect the key mechanisms regulating water balance, fluid intake, and AVP release in response to water deprivation. Collectively, these novel results highlight the impact of perinatal programming on the homeostatic mechanisms regulating fluid and electrolyte balance during exposure to an environmental stress (i.e. dehydration) in later life.
Matched MeSH terms: Water Deprivation/physiology; Water-Electrolyte Balance/drug effects
Biocatalyst should have sufficient and efficient activity for the intended
biotechnological application. In the quest for novel biocatalyst, there is a need to have a
genetic diversity either by finding it within the astronomically large number of possible
candidates or to obtain it by bioengineering an existing gene supported by various
bioinformatic and molecular engineering tools. Nowadays, it is well-known that a huge
number of microorganisms is unculturable and poses great challenges to access biocatalysts
from these microbes. Metagenomics is one of the methods widely applied to reach out
maximum possible variants to “bioprospect” biocatalysts. On the other hand, other approaches
are available to bioengineer enzymes by modifying the DNA sequence precisely based on the
structure and the function information of the protein in the case of rational design, or by a
brave creation of anarchic mutations of the DNA sequence with directed evolution method. In
this regard, both approaches, whether to bioprospect or to bioengineer biocatalysts have
advantages and disadvantages which will be discussed in this paper.KEY WORDS: Sugar
industry wastewater; aluminium sulphate; primary treatment, ferric chloride; polyaluminium
chloride
sugar industry is one of the industries that produce a high amount of
pollutant since its wastewater contains high amount of organic material, biochemical
oxygen demand (bod) and chemical oxygen demand (cod). if this waste is
discharged without a proper treatment into the watercourse, it can cause problem to aquatic
life and environment. for the primary treatment process, sugar wastewater can be treated
by using chemical precipitation method which involves coagulation process. currently,
ferric chloride has been used as the coagulant but it consumes more alkalinity and
corrosive. in this study, the suitable coagulant to be used to treat the wastewater from sugar
industry and the optimum conditions to achieve high percentage removal of cod was
determined. the characteristic of the wastewater was firstly determined. then, the most
suitable coagulant to be used for the treatment was studied by determining their efficiency
to reduce cod and tss in the wastewater at different dosages. aluminium sulphate
(alum), ferric chloride and polyaluminium chloride (pac) were chosen to be studied for
suitable coagulant. The optimum condition of the coagulant (ph, coagulant dosage, fast
mixing speed) was determined by using design expert software. results showed that alum
can be used to effectively remove 42.9% of cod and 100% of tss at high dosage (50
mg/l). the optimum condition of alum was at ph 5.2, 10 mg/l of alum and 250 rpm of
mixing speed. this shows that at optimum condition, alum can be used to treat wastewater
from sugar industry.
Growing plants in the gulf region can be challenging as it is mostly desert, and the climate is dry. A few species of plants have the capability to grow in such a climate. However, those plants are not suitable as a food source. The aim of this work is to design and construct an indoor automatic vertical hydroponic system that does not depend on the outside climate. The designed system is capable to grow common type of crops that can be used as a food source inside homes without the need of large space. The design of the system was made after studying different types of vertical hydroponic systems in terms of price, power consumption and suitability to be built as an indoor automated system. A microcontroller was working as a brain of the system, which communicates with different types of sensors to control all the system parameters and to minimize the human intervention. An open internet of things (IoT) platform was used to store and display the system parameters and graphical interface for remote access. The designed system is capable of maintaining healthy growing parameters for the plants with minimal input from the user. The functionality of the overall system was confirmed by evaluating the response from individual system components and monitoring them in the IoT platform. The system was consuming 120.59 and 230.59 kWh respectively without and with air conditioning control during peak summer, which is equivalent to the system running cost of 13.26 and 25.36 Qatari Riyal (QAR) respectively. This system was circulating around 104 k gallons of nutrient solution monthly however, only 8-10 L water was consumed by the system. This system offers real-time notifications to alert the hydroponic system user when the conditions are not favorable. So, the user can monitor several parameters without using laboratory instruments, which will allow to control the entire system remotely. Moreover, the system also provides a wide range of information, which could be essential for plant researchers and provides a greater understanding of how the key parameters of hydroponic system correlate with plant growth. The proposed platform can be used both for quantitatively optimizing the setup of the indoor farming and for automating some of the most labor-intensive maintenance activities. Moreover, such a monitoring system can also potentially be used for high-level decision making, once enough data will be collected. This work presents significant opportunities for the people who live in the gulf region to produce food as per their requirements.
We report a new series of lipid-based biocompatible ionic liquids (LBILs) consisting of the long-chain phosphonium compound 1,2-dimyristoyl-sn-glycero-3-ethyl-phosphatidylcholine as the cation and the long-chain fatty acids stearic acid, oleic acid, or linoleic acid as anions. These materials were found to be completely miscible with many polar and nonpolar organic solvents as well as dispersible in water. These LBILs also exhibited excellent biocompatibility with an artificial three-dimensional human epidermis model.
Increasing population, urbanization and industrial activities have increased the amount of solid waste worldwide. Food waste (FW) and sewage sludge (SS) are some of the solid wastes. Co-digesting of both substrates may improve process stabilization to increase biogas production and overcome the nutrients imbalance. Thus, anaerobic co-digestion has been recognized as a technology that could provide a clean renewable energy source and help reducing the landfill problem. In this study, the interaction between FW and SS as co-substrates in anaerobic digestion was studied under mesophilic temperature 36C (± 0.5). The experiments were conducted using five batch reactors with different ratios of substrates. There are four different analyses used to identify the characteristics of FW and SS, which are pH, reducing sugar (RS), total solid (TS), and total carbohydrate (TC). Water displacement method was used to record biogas yield. The experimental results showed that the highest biogas yield was from the composition of 50:50 (FW: SS) with a biogas volume of 1150.14 mL, while the least was the composition of 0:100 (FW: SS) with 170.47 mL biogas produced. The results for substrate degradation showed that the composition of 100:0 (FW: SS) has the highest percentage degradation for reducing sugar with the percentage of 56%, while the minimum was 0:100 (FW: SS) with a percentage of 35%. Besides, for TC, the highest percentage of degradation was the composition 50:50 (FW: SS) with 84%, and the least was 0:100 (FW: SS) with 44%. This study proves that using FW and SS enhanced biogas production as well as reducing the current issues of waste disposal.
In this paper, ambient total suspended particulates (TSP) with a focus on humic-like substances (HULIS) are characterized based on intensive ground-based field samplings collected in Malaysia during non-haze and haze periods caused by peatland fires on the Indonesian island of Sumatra. Furthermore, concentrations of water-soluble organic carbon (WSOC) and carbon content of HULIS (HULIS-C) were determined, and fluorescence spectra of the HULIS samples were recorded by excitation emission matrix (EEM) fluorescence spectroscopy. The concentrations of WSOC and HULIS-C over the entire period ranged from 4.1 to 24 and 1.3 to 18 μgC m-3, respectively. The concentrations of WSOC and HULIS-C during the peatland fire-induced strong haze periods were over 4.3 and 6.1 times higher, respectively, than the average values recorded during the non-haze periods. Even during the light haze periods, the concentrations of WSOC and HULIS-C were significantly higher than their averages during the non-haze periods. These results indicate that peatland fires induce high concentrations of WSOC, particularly HULIS-C, in ambient TSP at receptor sites. EEM fluorescence spectra identified fulvic-like fluorophores at the highest intensity level in the EEM fluorescence spectra of the haze samples. A peak at excitation/emission (Ex/Em) ≈ (290-330)/(375-425) nm is also observed at high intensity, though this peak is normally associated with marine humic-like fluorophores. It is shown that a peak at Ex/Em ≈ (290-330)/(375-425) nm is not derived from marine sources only; furthermore, peatland fires are shown to be important contributors to HULIS around this peak.
A new micro heat exchanger was analyzed using numerical formulation of conjugate heat transfer for single-phase fluid flow across copper microchannels. The flow across bent channels harnesses asymmetric laminar flow and dean vortices phenomena for heat transfer enhancement. The single-channel analysis was performed to select the bent channel aspect ratio by varying width and height between 35-300 μm for Reynolds number and base temperature magnitude range of 100-1000 and 320-370 K, respectively. The bent channel results demonstrate dean vortices phenomenon at the bend for Reynolds number of 500 and above. Thermal performance factor analysis shows an increase of 18% in comparison to straight channels of 200 μm width and height. Alumina nanoparticles at 1% and 3% concentration enhance the Nusselt number by an average of 10.4% and 23.7%, respectively, whereas zirconia enhances Nusselt number by 16% and 33.9% for same concentrations. On the other hand, thermal performance factor analysis shows a significant increase in pressure drop at high Reynolds number with 3% particle concentration. Using zirconia for nanofluid, Nusselt number of the bent multi-channel model is improved by an average of 18% for a 3% particle concentration as compared to bent channel with deionized water.
In this research, the physical, mechanical and morphological properties of oil palm empty fruit bunch (EFB) mat/woven kenaf fabric-reinforced epoxy composites have been investigated. The oil palm EFB/woven kenaf fabrics were varied, with weight ratios of 50/0 (T1), 35/15 (T2), 25/25 (T3), 15/35 (T4) and 0/50 (T5). The composites were fabricated using a simple hand lay-up technique followed by hot pressing. The result obtained shows that an increase in kenaf fiber content exhibited higher tensile and flexural properties. On the other hand, the opposite trend was observed in the impact strength of hybrid composites, where an increase in kenaf fiber content reduced the impact strength. This can be corroborated with the physical properties analysis, where a higher void content, water absorption and thickness swelling were observed for pure oil palm EFB (T1) composites compared to other samples. The scanning electron microscopy analysis results clearly show the different failure modes of the tensile fractured samples. Statistical analysis was performed using one-way ANOVA and shows significant differences between the obtained results.