Pharmaceutical delivery systems are developed to improve the physicochemical properties of therapeutic compounds. Emulsions are one of these drug delivering systems formulated using water, oils and lipids as main ingredients. Extensive data are usually generated on the physical and chemical characteristics of these oil-in-water and lipid emulsions. However, the oxidative tendency of emulsions is often overlooked. Oxidation impacts the overall quality and safety of these pharmaceutical emulsions. Additionally, introducing oxidatively unstable emulsions into biological systems further promotes oxidation in situ. Products of these reactions then continue to pose serious harm to cells and fuel other physiological oxidation reactions. Consequently, the increase of oxidation products leads to oxidative damage to biological systems. Thus, emulsions with lower lipid peroxidation are more stable and will reduce the negative effects of oxidation in situ. Preventive measures during the formulation of emulsions are important. Many naturally occurring and cost effective substances possess low oxidation tendencies and confer oxidative protection when used in emulsions. Additionally, certain preparatory methods should be employed to reduce or better control lipid peroxidation. Finally, emulsions must be evaluated for their oxidation susceptibility using the various techniques available. Careful attention to the preparation of emulsions and assessment of their oxidative stability will help produce safer emulsions without compromising efficacy.
The assessment of water-extractable organic matter using an autoclave can provide useful information on physical, chemical, and biological changes within the soil. The present study used virgin forest soils from Chini Forest Reserve, Langkawi Island, and Kenyir Forest Reserve (Malaysia), extracted using different extraction methods. The dissolved organic carbon (DOC), total dissolved nitrogen (TDN), total dissolved phosphorus (TDP), and ammonium-nitrate content were higher in the autoclave treatments, up to 3.0, 1.3, 1.2, and 1.4 times more than by natural extraction (extracted for 24 h at room temperature). Overall, the highest extractable DOC, TDN, TDP, ammonium and nitrate could be seen under autoclaved conditions 121 °C 2×, up to 146.74 mg C/L, 8.97 mg N/L, 0.23 mg P/L, 5.43 mg N mg/L and 3.47 N mg/L, respectively. The soil extracts became slightly acidic with a higher temperature and longer duration. Similar trends were observed in the humic and nonhumic substances, where different types of soil extract treatments influenced the concentrations of the fractions. Different soil extraction methods can provide further details, thus widening the application of soil extracts, especially in microbes.
Staphylococcus spp. are Gram-positive bacteria that reside within the normal microbiota of humans and animals but pose a health threat as reservoirs of antimicrobial resistance genes. Here, we present the draft genome sequences of three Staphylococcus sp. strains isolated from hospital wastewater in Malaysia that demonstrated resistance to multiple antibiotics.
Renewable materials have some bearing on the environment and have since increased research works related to polymer composites. This work was conducted to investigate the effects of interwoven kenaf fibres and the use of kenaf fibres in composites. In this research, interwoven between kenaf and polyethylene terephthalate (PET) was prepared and epoxy was used as the polymer matrix to form composites. The kenaf fibre composites with various kenaf fibre contents (2, 5, 8, and 10 wt %) interwoven with (PET) fibres were prepared by using open mould method. The properties of kenaf/PET/epoxy composites (KPTE) were studied. The kenaf fibre composites characterization was determined based on their mechanical properties, water absorption, morphology and thermal properties. The tensile strength test was performed using Testometric machine. The finding shows that the strength increases as the amount of kenaf fibres in the composites increases. The composites with 10% kenaf fibres interwoven PET displayed the highest tensile strength (85.3 ± 2.9 MPa) while unfilled epoxy show the lowest tensile strength (64.1 ± 16.5 MPa). The addition of kenaf fibres minimally increases the water absorption up to about 1.4%. The increases of kenaf fibres also reduces the overall thermal stability of the composites compared to the PET and epoxy resin composites. The morphology properties of KPTE composites support the tensile properties surface of the composites. This study assists to propose the kenaf fibres as a potential filler for properties improvements in epoxy-based composites contributing to the development of another environment-friendly material.
Concerning on navigational safety of a ship, comprehensive investigation of manoeuvrability of the ship is prominently required. The turning instability due to improper speed and magnitude of the rudder angle is vulnerable to serious accidents such as collision especially in the confined waters. This paper presents a computational fluid dynamic analyses on manoeuvrability performance of a tug in calm water. Here, the characteristics of the turning ability and zig-zag characteristics of the tug has been assessed due to effect of the various angles of twin-rudder and turning speeds. The results revealed that the increase of rudder’s angle resulted in subsequent reduction of her advance diameter from 144 m, 108 m, 96 m to 92 m. While for zig zag manoeuvre, the first overshoot angle is 0.6° and 1.08° for 10°/10° and 20°/20° rudder’s angle respectively. The first overshoot and second overshoot angle are within the IMO criteria which is below 20° and 25°. However, the increase of turning speed from 7 knots to 9 knots has been proportional with the increase of the turning diameter (advance diameter) from 70 m to 105.2 m. Basically, the turning performances of the tug manoeuvring with the turning speed of 7 to 9 knots incorporated with rudder’s angle 20°, 25°, 30° and 35° have been complied with IMO manoeuvring standards. This preliminary analysis contributes very valuable findings at early ship design stage to provide a safety of the navigational guidance for turning ability of the tug.
Trawling is a method of catching fish in a large volume where fish net is pulled through water using one or two boats. Bottom trawling is where the nets are pulled over or close to seabed and can affect the subsea pipeline if found along the route. Therefore, the objective of this study was to determine the impact of pull-over to selected subsea pipelines in Sabah and Labuan waters. This study involved four oil and gas pipelines in Sabah and Labuan waters from the oil fields to shore terminals. The research started with obtaining data of the pipelines and specification of trawl gear in Sabah. Fishing trawler traffic data along the pipelines route was determined by AIS system and site observation to determine the density of the trawlers. Trawl gear pull-over load was calculated using DNV algorithm and the inputs were trawl gear specification ^and fishing trawl speed. The severity was based on pull-over load calculated and pipeline yield stress. Then frequency was based on AIS data and density of fishing trawl per area. Based on the comparison between trawl pull-over load and yield strength/stress, the effect of trawl board pull-over is considered as minor, which is the lowest in the severity index.
Underwater wireless communications refer to transmitting data in an unguided water environment by wireless carriers including acoustic, radio frequency (RF), and optical waves. Relative to acoustic and RF, the optical wave is more promising to offer higher bandwidth at a lower energy consumption rate. However, an optical wave has its challenges such as attenuation due to absorption, scattering and turbulence effects. Therefore, this work attempts to investigate the performance of lightwave propagation for underwater optical wireless communication (UOWC) using simulation and experimental approaches. First, the performance of optical waves was analyzed using MATLAB by simulating the light attenuation model which based on depth-dependent chlorophyll concentration. A depth profile that related to the surface chlorophyll levels for the range 0-4 mg/m3 was used to represent the open ocean. The simulation showed that the attenuation of light less affected for operating wavelength range of 450 – 550 nm. Further, an experimental set-up was developed which consists of a transmitter, receiver, and aquarium to emulate the UOWC channel. Three types of water including clear, sea and cloudy were tested to analyze their interaction with the light emitted by a light-emitting diode (LED) and a laser diode. The emitted light detected by the light sensor and the strength of an audio signal transmitted through the UOWC were measured using a light meter and sound meter respectively. The measured power was plotted against distance and the attenuation constant c was deduced through curve fitting method. The analysis showed irrespective of the light sources, UOWC in cloudy water suffered the highest attenuation relative to still clear and seawater. The received power emitted by laser was at least 41% higher than the LED. This study contributes to identify the potential and limitations of different operating schemes to optimize UOWC performance.
Pink Antigonon leptopushave potential to be commercialized as cut flowers for flower arrangement. In order to determine cut inflorescences' vase life, vase solution treatments containing Artificial Tap Water as control, salicyclic acid (SA) at 100, 200, 300 mg/L and combination of 100, 200, 300 mg/L SA with 2% sucrose were conducted. Parameters observed were vase life, relative fresh weight (RFW), vase solution uptake (VSU), flower drop (FD), flower colour, relative water content (RWC) and pH. The results showed that cut inflorescences in vase treatment containing 200 mg/L SA + 2% sucrose and 300 mg/L + 2% sucrose had 1.6 fold longer vase life than the control, showing higher water uptake and reduced flower drop by 28%.
Nowadays, Kenaf fiber is sustainably useful in marine structures and has become one of the materials that may be high in demand as it is light, biodegradable and environmental friendly. This study investigates the effect of fiber percentage on compressive strength of fiber reinforced concrete (FRC) and the relationship between compressive strength and time of FRC immersion in seawater. FRC concrete cubes were prepared using four different percentage of fiber (0%, 1.5%, 3.0% and 4.5%). These FRC were immersed in seawater for 7, 14 and 21 days for three consecutive weeks. Based on the experiment, it was found that there was improvement in compressive strength of FRC when compared to plain cement concrete. The results showedthat 3.0% of KF to cement matrix concrete determined the highest compressive strength of 205.43 Pa while 0% of KF fiber to cement concrete matrix (control specimen) showed the lowest compressive strength of 158.28 Pa. Also the addition of Kenaf fiber to cement concrete decreased the seawater absorption more than concrete with absolutely 0% of KF fiber to cement concrete (control specimen). In conclusion, the results did show significant improvement and a consistent trend on strength with the addition of FRC. This study also revealed that the percentage of water absorption was on the increase for 0, 7 and 14 days and become constant after day 21. This is due to manufacturing defects that occurred which block the water from entering the material and making the material absorb less water.
Freshwater fishes are species that spend their entire live in either freshwater inland or brackish estuaries. The checklist of the fish species should be updated consistently to ensure their diversity is preserved. The study of diversity and distribution of freshwater fishes at Sungai Muar, Kuala Pilah, Negeri Sembilan was carried out on 14 and 15 March 2020 to identify the fish diversity and their development in Sg. Muar, Negeri Sembilan. Trawl (fish collections), weighing machine and ruler (morphometric observations) was used during experiment. Fish species found during this study include Oreochromis mossambicus (Family Cichlidae), Hemibagrus nemurus (Family Bagridae), Homaloptera tweediei (Family Balitoridae), Notopterus notopterus (Family Notopteridae), Oxyeleotris marmorata (family Eleotridae), and five species of Family Cyprinidae, which were Mystacoleucus marginatus, Osteochilus haseltii, Cyclocheilichthys apogon, Barbonymus schwanenfeldii and Hampala microlepidota. Fishes from family Cyprinidae was dominated the area with a total of 102 individuals found. The statistical analysis shows the diversity (H’)=1.826, richness (R’)=2.004 and evenness (E’)= 0.5645 of freshwater fish at Sungai Muar, respectively. The most dominant species found was Mystacoleucus marginatus with 50 individuals and the least abundant species were Barbonymus schwanenfeldii, Homaloptera tweediei and Oxyeleotris marmorata with one individual only. The length-weight regression shows a positive allometric growth with ‘b’ value is higher than 3 at both stations; 3.0118 (Station 1) and 3.4409 (Station 2). It shows that the fish becomes heavier as its length increases. This data provides information about the fish habitat in Sungai Muar and can be used to update the checklist of fish species in Sg Muar. The data obtained provides information about the fish habitat in Sungai Muar which could be useful for the planning of fishing activities Other than that, it also important as a guideline for future research and conservation purposes especially in Negeri Sembilan.
Understanding the genetic mechanism of osmoregulation is important for the improvement of salt tolerance in tilapia. In our previous study, we have identified a major quantitative trait locus (QTL) region located at 23.0 Mb of chrLG18 in a Nile tilapia line by QTL-seq. However, the conservation of these QTLs in other tilapia populations or species is not clear. In this study, we successfully investigated the QTLs associated with salt tolerance in a mass cross population from the GIFT line of Nile tilapia (Oreochromis niloticus) using a ddRAD-seq-based genome-wide association study (GWAS) and in a full-sib family from the Malaysia red tilapia strain (Oreochromis spp) using QTL-seq. Our study confirmed the major QTL interval that is located at nearly 23.0 Mb of chrLG18 in Nile tilapia and revealed a long QTL cluster across chrLG18 controlling for the salt-tolerant trait in both red tilapia and Nile tilapia. This is the first GWAS analysis on salt tolerance in tilapia. Our finding provides important insights into the genetic architecture of salinity tolerance in tilapia and supplies a basis for fine mapping QTLs, marker-assisted selection, and further detailed functional analysis of the underlying genes for salt tolerance in tilapia.
This study was set up to model and optimize the performance and emission characteristics of a diesel engine fueled with carbon nanoparticle-dosed water/diesel emulsion fuel using a combination of soft computing techniques. Adaptive neuro-fuzzy inference system tuned by particle swarm algorithm was used for modeling the performance and emission parameters of the engine, while optimization of the engine operating parameters and the fuel composition was conducted via multiple-objective particle swarm algorithm. The model input variables were: injection timing (35-41° CA BTDC), engine load (0-100%), nanoparticle dosage (0-150 μM), and water content (0-3 wt%). The model output variables included: brake specific fuel consumption, brake thermal efficiency, as well as carbon monoxide, carbon dioxide, nitrogen oxides, and unburned hydrocarbons emission concentrations. The training and testing of the modeling system were performed on the basis of 60 data patterns obtained from the experimental trials. The effects of input variables on the performance and emission characteristics of the engine were thoroughly analyzed and comprehensively discussed as well. According to the experimental results, injection timing and engine load could significantly affect all the investigated performance and emission parameters. Water and nanoparticle addition to diesel could markedly affect some performance and emission parameters. The modeling system could predict the output parameters with an R2 > 0.93, MSE water content of 2.49 wt%. The carbon dioxide, carbon monoxide, nitrogen oxides, and unburned hydrocarbon emission concentrations were found to be 7.26 vol%, 0.46 vol%, 95.7 ppm, and 36.2 ppm, respectively, under the selected optimal operating conditions while the quantity of brake thermal efficiency was found at an acceptable level (34.0%). In general, the applied soft computing combination appears to be a promising approach to model and optimize operating parameters and fuel composition of diesel engines.
This study investigates the potential of using small amounts of ionic liquids (IL) to enhance ultrasound-assisted extraction of lipids content from green microalgae. Three imidazolium-based ILs (butyl, octyl and dodecyl), each of them with two anions (bromide and acetate) were tested as additives. Viscosity and surface tension of the ILs aqueous mixtures were analyzed to determine the influence of ILs' anions and alkyl chain length, whereas KI dosimetry experiments were used as an indicator of radicals formation. A key finding suggests that the small addition of ILs improves the ultrasonication either by enhancing the viscosity and reducing the water surface tension, leading to a more powerful acoustic cavitation process or by increasing HO° production likely to oxidize the microalgae cells membranes, and consequently disrupting them on a more efficient manner. KI dosimetry also revealed that long ILs alkyl chain is detrimental. This experimental observation is confirmed thus strengthened as the yield of extracted lipids from green microalgae has shown an incremental trend when the IL concentration also increased. These hypotheses are currently under investigation to spot detailed impact of ILs on cavitation process.
Powdered-photocatalysis of organic wastewater is widely investigated, unfortunately not industrially implemented due to its high energy requirement. Interestingly, such issue may be alleviated via the elimination of mechanical stirring required. Core-shell ZnO-based photocatalysts were developed herein, subsequently demonstrated efficient photocatalytic activities in the absence of mechanical stirring. Results show that the developed SiO2-cored ZnO photocatalyst are highly crystalline, while significantly smaller than coreless, pure ZnO due to the multi-point crystallization prompted. Additionally, it is also inherited with considerable buoyancy ability from SiO2-core in the absence of mechanical stirring, concurrently rendered with UV-active properties due to its ZnO-shell. Experimentally, 55% of particles of ZnO_0.0025 (0.0025 mol of ZnO-deposition) were found stably suspended for 60 min in liquid substrate, as opposed to the instant-settling of pure ZnO particles. In term of photocatalytic activity, ZnO_0.01 manifested the best methylene blue (MB) degradation with 150 mL/min of O2-bubbling. 67.63% of MB was degraded with photocatalyst loading of 0.2 g/L after 120 min UV-irradiation, simultaneously recorded the highest pseudo-first order reaction constant of 9.636 × 10-3 min-1. As summary, the auto-suspending photocatalysis conceptualized in current study offers a high possibility in reducing energy requirement for photo-treatment of wastewater, hence advocating its industrialization potential in near future.
Floating plastic debris was investigated in the transition region in the North Pacific between 141°E and 165°W to understand its transportation process from Asian coast to central subtropical Pacific. Distribution was influenced primarily by the current system and the generation process of the high concentration area differed between the western and eastern areas. West of 180°, debris largely accumulated around nearshore convergent area and was transported by eddies and quasi-stationary jet from south to the subarctic region. The average was 15% higher than that previously reported in 1989, suggesting an increase in plastic debris in 30 years. East of 180°, debris concentrated in the calm water downstream of the Kuroshio Extension Bifurcation with considerably high concentration (505,032 ± 991,989 pieces km-2), due to the accumulation of small transparent film caused by calm weather conditions, suggesting a further investigation on small plastic (<1 mm) in the subsurface depth in the subtropical North Pacific.
We isolated fifty-two strains from the marine aquaculture ponds in Malaysia that were evaluated for their lipid production and ammonium tolerance and four isolates were selected as new ammonium tolerant microalgae with high-lipid production: TRG10-p102 Oocystis heteromucosa (Chlorophyceae); TRG10-p103 and TRG10-p105 Thalassiosira weissflogii (Bacillariophyceae); and TRG10-p201 Amphora coffeiformis (Bacillariophyceae). Eicosapentenoic acid (EPA) in three diatom strain was between 2.6 and 18.6 % of total fatty acids, which were higher than in O. heteromucosa. Only A. coffeiformi possessed arachidonic acid. Oocystis heteromucosa naturally grew at high ammonium concentrations (1.4-10 mM), whereas the growth of the other strains, T. weissflogii and A. coffeiformi, were visibly inhibited at high ammonium concentrations (>1.4 mM-NH4). However, two strains of T. weissflogii were able to grow at up to 10 mM-NH4 by gradually acclimating to higher ammonium concentrations. The ammonium tolerant strains, especially T. weissflogii which have high EPA contents, were identified as a valuable candidate for biomass production utilizing NH4-N media, such as ammonium-rich wastewater.
Matched MeSH terms: Water Pollutants, Chemical; Water Purification; Waste Water/microbiology*
Synthetic fibers such as glass fiber and carbon fiber are traditionally used as reinforcement in engineering composites. The increasing of environmental concerns has led to the use of natural fibers as renewable alternatives reinforcement. Among them, coconut meat husk fiber which abundant availability can be used as reinforcement fiber. However, the coconut meat husk fiber, same as other natural fibers, has the issues of fiber/matrix bonding and moisture absorption. Chemical treatments are needed to modify the surface of fiber, aiming at improving the adhesion with polymer matrix and reducing the hydrophilicity of the fiber. Alkalization was used in this study to treat the coconut meat husk fiber. The effects of chemical treatments for 1hr and 24 hr treatment time on the coconut meat husk fibers reinforced composites were investigated. A result showed that the 24 hr alkali treatment gave the highest tensile stenght compared to the 1hr treatment and RO water.
Vibrio parahaemolyticus is a causative agent of foodborne outbreaks associated with the consumption of raw or under-cooked seafood. This study aimed to quantify and detect the occurrence of V. parahaemolyticus in freshwater fish by performing Most Probable Number (MPN) method in combination with Polymerase Chain Reaction (PCR). In this study, a total of 20 red tilapia (Oreochromis sp.) were collected from nearby local wet markets. Polymerase Chain Reaction (PCR) assay targeting the toxR gene in V. parahaemolyticus was performed, with the expected DNA amplification size of 368 bp. MPN analysis showed that the estimated microbial load of V. parahaemolyticus were more than 1100 MPN/g. The result of the PCR assay confirmed the presence of V. parahaemolyticus in 90% of the isolates. This positive detection elucidated the presence of food-borne bacteria in freshwater fish from local wet-market which may affect not only the health of fish stocks but also raise public health concerns.
In the present paper, the potentiality of integrating microbial fuel cells (MFCs) with a photocatalytic reactor to maximize the wastewater treatment efficiency with concurrent power generation was explored. Dimethyl phthalate (DMP) and acetic acid (AA) were the employed substrate and the co-substrate, respectively, using Pseudomonas aeruginosa as a biocatalyst. MFCs operated by single substrate showed the maximum power generation of 0.75-3.84 W m-3 whereas an addition of AA as the co-substrate yielded 3-12 fold higher power generation. Pseudomonas aeruginosa produced phenazine-1-carboxylic acid in DMP-fed MFC as the metabolite whereas AA along with DMP yielded pyocyanin which reduced the charge transfer resistance. Chemical oxygen demand (COD) removal efficiency in the MFCs was circa 62% after 11 days of operation. Thereafter, it further increased albeit with a drastic reduction in power generation. Subsequently, the MFC anolyte was treated in a photocatalytic reactor under visible light irradiation and catalyzed by CuO-gC3N4. The performance of photocatalytic reactor was evaluated, with COD and total organic carbon (TOC) removal efficiency of 88% and 86% after 200 min of light irradiation. The present work suggests that the MFC can be integrated with photocatalysis as a sustainable wastewater treatment method with concurrent power generation.
Herein, we report the facile synthesis, characterization and visible-light-driven photocatalytic degradation of perforated curly Zn0.1Ni0.9O nanosheets synthesized by hydrothermal process. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) studies confirmed the cubic phase crystalline structure and growth of high density perforated curly Zn0.1Ni0.9O nanosheets, respectively. As a photocatalyst, using methylene blue (MB) as model pollutant, the synthesized nanosheets demonstrated a high degradation efficiency of ~76% in 60 min under visible light irradiation. The observed results suggest that the synthesized Zn0.1Ni0.9O nanosheets are attractive photocatalysts for the degradation of toxic organic waste in the water under visible light.