In the Peninsular Malaysia and Northern Borneo island of Malaysia, various rich indigenous leafy vegetables and fruits grow and contribute to the nutritional and dietary values of the population. They have high water ...In the Peninsular Malaysia and Northern Borneo island of Malaysia, various rich indigenous leafy vegetables and fruits grow and contribute to the nutritional and dietary values of the population. They have high water contents, thus, naturally vulnerable to rapid food spoilage. Food preservation and processing play a vital role in the inhibition of food pathogens in fruits and vegetables that are prevalent in Malaysia. Lactic acid fermentation is generally a local-based bioprocess, among the oldest form and well-known for food-processing techniques among indigenous people there. The long shelf life of fermented vegetables and fruits improves their nutritional values and antioxidant potentials. Fermented leaves and vegetables can be utilized as a potential source of probiotics as they are host for several lactic acid bacteria such as Lactobacillus confusus, Weissella paramesenteroides, Enterococcus faecalis, Lactobacillus plantarum, Lactobacillus buchneri, Lactobacillus paracasei, Lactobacillus pentosus, Pediococcus acidilactici, Pediococcus pentosaceus and Leuconostoc mesenteroides. These strains may be more viable in metabolic systems whereby they can contribute to a substantial increase in essential biologically active element than industrial starter cultures. This review is aimed to address some essential fermented fruits and vegetables in Malaysia and their remarkable reputations as a potential sources of natural probiotics.展开更多
Objective:To investigate antioxidant and antimicrobial activities of two plant species,Litsea elliptica(L elliptica) and Litsea resinosa(L resinosa).Methods:In vitro method-2,2-diphenyl-1-picrylhydrazyl radical scaven...Objective:To investigate antioxidant and antimicrobial activities of two plant species,Litsea elliptica(L elliptica) and Litsea resinosa(L resinosa).Methods:In vitro method-2,2-diphenyl-1-picrylhydrazyl radical scavenging assay was conducted for antioxidant activity detennination while antimicrobial assay consisted of agar well diffusion assay and mycelial radial growth assay.Results:Methanol extracts of root and stem of L elliptica and L resinosa exhibited the highest antioxidant activity with EC_(50)of 23.99,41.69,11.22 and 33.48 mg/l.respectively.All methanol extracts of L resinosa as well as root extracts from L elliptica showed significant scavenging activity.Hexane extract from stem of L resinosa presented the largest inhibition zone in Gramnegative bacteria Pseudomonas aeruginosa and Escherichia coli while chloroform extract from inner bark of L resinosa showed major inhibition towards Gram-positive bacteria Bacillus subtilis.Essential oils from the root of both species showed significant antifungal activities which are 80.11%and 66.85%respectively.Conclusions:Overall,methanol extracts from root and stem of both species showed antioxidant activity comparable to standard butylated hydroxytoluene.Extracts from L resinosa demonstrated stronger antimicrobial properties compared to that from L elliptica.展开更多
Developments along the Santubong River basin may have an impact on the aquatic ecosystem. To determine the impacts of activities on the water quality, ten stations were selected for water quality study over 9 months. ...Developments along the Santubong River basin may have an impact on the aquatic ecosystem. To determine the impacts of activities on the water quality, ten stations were selected for water quality study over 9 months. Results show that salinity increases from 14.0 PSU upstream to 30.4 PSU downstream. Lowest DO range was 2.3-4.1 mg/L. TSS ranged was 20-135 mg/L and the highest was observed near construction and residential areas, the second and third highest near shrimp culture discharge areas. BOD5 was the highest near construction and residential areas. BOD5 of a station near shrimp culture was not significantly different from the residential areas. Two stations near shrimp culture site also recorded the highest Chl-a. The highest ammonia-nitrogen, nitrite-nitrogen and reactive phosphorus were observed at stations near shrimp farm sites whereas nitrate-nitrogen was the highest near construction and residential areas. Cage culture site showed the highest phosphorus and second highest nitrite-nitrogen and ammonia-nitrogen. This study showed that TSS and BOD5 were elevated near residential and construction areas and nutrients were elevated near shrimp farm sites resulting in algal bloom. Therefore, it is recommended that residential and shrimp farm discharge be treated to acceptable quality before discharge to protect the aquatic resources.展开更多
The use of nanosized titanium dioxide（TiO2） and zinc oxide（ZnO） in the suspension form during treatment makes the recovering and recycling of photocatalysts difficult.Hence,supported photocatalysts are preferred f...The use of nanosized titanium dioxide（TiO2） and zinc oxide（ZnO） in the suspension form during treatment makes the recovering and recycling of photocatalysts difficult.Hence,supported photocatalysts are preferred for practical water treatment applications.This study was conducted to investigate the efficiency of calcium alginate（CaAlg） beads that were immobilized with hybrid photocatalysts,TiO2/ZnO to form TiO2/ZnO-CaAlg.These immobilized beads,with three different mass ratios of TiO2：ZnO（1：1,1：2,and 2：1） were used to remove Cu（Ⅱ） in aqueous solutions in the presence of ultraviolet light.These beads were subjected to three cycles of photocatalytic treatment with different initial Cu（Ⅱ） concentrations（10-80 ppm）.EDX spectra have confirmed the inclusion of Ti and Zn on the surface of the CaAlg beads.Meanwhile,the surface morphology of the beads as determined using SEM,has indicated differences of before and after the photocatalytic treatment of Cu（Ⅱ）.Among all three,the equivalent mass ratio TiO2/ZnO-CaAlg beads have shown the best performance in removing Cu（Ⅱ） during all three recycling experiments.Those TiO2/ZnO-CaAlg beads have also shown consistent removal of Cu,ranging from 7.14-52.0 ppm（first cycle） for initial concentrations of10-80 ppm.In comparison,bare CaAlg was only able to remove 6.9-48 ppm of similar initial Cu concentrations.Thus,the potential use of TiO2/ZnO-CaAlg beads as environmentally friendly composite material can be further extended for heavy metal removal from contaminated water.展开更多
Stable colloidal suspension of magnetite/starch nanocomposite was prepared by a facile and aqueous-based chemical precipitation method, Magnetite/carbon nanocomposite thin films were subsequently formed upon carboniza...Stable colloidal suspension of magnetite/starch nanocomposite was prepared by a facile and aqueous-based chemical precipitation method, Magnetite/carbon nanocomposite thin films were subsequently formed upon carbonization of the starch component by heat treatment under controlled conditions. The initial content of native sago starch as the carbon source was found to affect the microstructure and electrochemical properties of the resulted magnetite/carbon nanocomposite thin films, A specific capacitance of 124 F/g was achieved for the magnetite/carbon nanocomposite thin films as compared to that of 82 F/g for pure magnetite thin films in Na2SO4 aqueous electrolyte.展开更多
Five new organotin(IV) complexes of ortho-vanillin-2-hydrazinopyridine hydrazone with formula [RnSnCl4–n(VHP)] [R = Me2, n = 2 (2);R = Ph2, n = 2 (3);R= nBu2, n = 2 (4);R = nBu, n = 2 (5) and R = 1, n = 0 (6)] have b...Five new organotin(IV) complexes of ortho-vanillin-2-hydrazinopyridine hydrazone with formula [RnSnCl4–n(VHP)] [R = Me2, n = 2 (2);R = Ph2, n = 2 (3);R= nBu2, n = 2 (4);R = nBu, n = 2 (5) and R = 1, n = 0 (6)] have been synthesized by direct reaction of ortho-vanillin-2-hydrazinopyridine hydrazone [(VHP), (1)], base and organotin(IV) chloride(s) in absolute methanol. The hydrazone ligand [(VHP), (1)] and its organotin(IV) complexes (2-6) have been characterized by UV-Visible, FT-IR and 1H NMR spectral studies. Spectroscopic data suggested that in the complexes (2-4), the ligand (1) acted as a neutral bidentate ligand and is coordinated to the tin(IV) atom via the azomethine nitrogen and pyridyl nitrogen atoms, whereas the ligand (1) acted as a uninegative tridentate ligand and coordinated to the tin(IV) atom through phenolic-O, azomethine-N and pyridyl-N atoms in complexes (5-6). The toxicity of the ligand (1) and its organotin (IV) complexes (2-6) were determined against Artemia salina. Organotin(IV) complexes showed moderate activity against Artemia salina. The ligand (1) and its organotin(IV) complexes (2-6) were also tested against four types of bacteria namely Bacillus cereus, Staphylococcus aureus, Escherichia coli and Enterobacter aerogenes. All organotin(IV) complexes and the free ligand (1) showed better antibacterial activities against bacteria. Among the organotin(IV) complexes (2-6), diphenyltin(IV) complex (3) showed higher activity against the four types of bacteria.展开更多
Sediment is a sink for organic materials, nutrients and heavy metals and sediment condition affects the overlying water Though Serin River is a source of drinking water, agricultural and waste disposal activities in t...Sediment is a sink for organic materials, nutrients and heavy metals and sediment condition affects the overlying water Though Serin River is a source of drinking water, agricultural and waste disposal activities in the watershed may impact the sediment of the river. Therefore, the objective of this study was to investigate the organic matter, nutrients and heavy metals in the sediment of the Serin River. Five stations were selected for sediment sample collection. Results of the study show that organic matter （OM） ranged from 0.7% to 5.9%, TP was 100 -366 （mg/kg）, TAN was 16-141 （mg/kg）, TON was 550-3019（mg/kg）, and TKN was 566-3160 （mg/kg）. Sediment oxygen demand （SOD20） ranged from 5.6 to 14.2 （g O2/m^2/d）. Among the five stations OM, TKN, and SOD of the sediment were second highest at the two stations downstream of animal （fish, chicken and pig） farming. TP and TAN were the second highest at the station downstream of fish farming and third highest at the station downstream of pig farming. Zn, Cu and Cd ranged from 132-357 （mg/kg）, 26.7-96.7 （mg/kg） and 4.0-19.3（mg/kg）. According to USEPA guideline, sediments at four stations were heavily polluted with Zn, Cu and Cd whereas the station that was farthest upstream, near a village, was slightly polluted with Zn and Cu. This study indicates that animal farming has an impact on the organic matter content, nutrients （N and P）, oxygen demand and heavy metals of the sediment. Motor vehicles and discarded e-waste also contributed to the heavy metals in the sediment. Farm effluents and storm water should be treated and e-waste recycled to protect the water quality of the river for its designated use.展开更多
Shrimp aquaculture is an important source of revenue for the state of Sarawak, Malaysia. However, there were concerns on the impact of shrimp farming on the mangrove ecosystem due to the discharge of shrimp pond water...Shrimp aquaculture is an important source of revenue for the state of Sarawak, Malaysia. However, there were concerns on the impact of shrimp farming on the mangrove ecosystem due to the discharge of shrimp pond water to the surrounding environment and potential self-pollution through the intake of surrounding water for the shrimp ponds. Therefore, the objectives of this study were to determine the water quality of the harvesting pond water and quantify the pollutants loadings. Samplings were conducted in three ponds and three channels near the pond outflow in a commercial shrimp farm during complete draining of water at harvest. Results indicated that TSS and Chl-a were high in both the ponds and channels. Total ammonia-nitrogen was the predominant form of the inorganic nitrogen and the mean values in both the ponds and channels were more than 1 mg/L which exceeded the maximum recommended for fish. Therefore, the water quality of the ponds and channel indicate that pond effluent should not be discharged directly into the surrounding environment but treated and nutrients recovered. Loads of total suspended solids, BODs, inorganic nitrogen, ammonia nitrogen, soluble reactive phosphorus and Chl-a of the effluent were quantified.展开更多
Pollen viability study on Piper colubrinum Link. carried out to develop interspecific hybridization between P. nigrum L. and P. colubrinum Link.. This plant has good potential as a donor plant in breeding programme fo...Pollen viability study on Piper colubrinum Link. carried out to develop interspecific hybridization between P. nigrum L. and P. colubrinum Link.. This plant has good potential as a donor plant in breeding programme for Phytophthora to foot rot resistance in the cultivated species, P. nigrum. This project was carried out to reveal the optimum time to collect pollen of P. colubrinum for artificial pollination. Through this study, anther dehiscence was proved occurred around 9 am. Based on the result obtained from study on the time of anther dehiscence, the pollen was classified into five stages for testing on the viability, i.e., stage 1, before anther dehiscence, i.e., around 7 am （pollen obtained by crushing on the anther）; stage 2： immediately after anther dehiscence, i.e., around 9 am; stage 3： two hours after anther dehiscence, i.e., around 11 am; stage 4： four hours after anther dehiscence, i.e., around 1 pm; and stage 5： six hours after anther dehiscence, i.e., around 3 pm. Data obtained from pollen germination and pollen tube growth study showed that pollen of P. colubrinum was the most viable at two hours after anther dehiscence and onward. It was also proved that the viability can be maintained up to at least eight hours. Pollen obtained before anther dehiscence by crushing on the anther was found less viable with lower percentage of pollen germination and retarded pollen tube growth. In other words, the experiment enlightened that artificial pollination between P. nigrum L. and P. colubrinum Link was ideally to be carded out approximately starting from 11 am until 5 pm, considering the viability of pollen ofP. colubrinum.展开更多
Objective:To demonstrate a noninvasive large mammalian genetic sampling method using blood meal obtained from a tabanid fly.Methods:Blood meal was recovered from the abdomen of an engorged tabanid fly(Haematopota sp.)...Objective:To demonstrate a noninvasive large mammalian genetic sampling method using blood meal obtained from a tabanid fly.Methods:Blood meal was recovered from the abdomen of an engorged tabanid fly(Haematopota sp.)which was captured immediately after biting a Sumatran rhino in captivity.The blood was applied on to a Whatman FTAblood card.Subsequent laboratory work was conducted to extract,amplify and sequence the DNA from the sample.Validation was done by sampling the hair follicles and blood samples from the rhinoceros and subjecting it to the same laboratory process.Results:BLAST search and constructed phylogenetic trees confirmed the blood meal samples were indeed from the rhino.Conclusions:This method could be used in the field application to noninvasively collect genetic samples.Collection of tabanids and other haematophagous arthropods(e.g.mosquitoes and ticks)and other blood-sucking parasites(e.g.leeches and worms)could also provide information on vector-borne diseases.展开更多
Aquaculture plays a major role in providing the needed protein. However, there have been reports of negative impacts of shrimp farming which include environmental pollution. Therefore, shrimp pond effluent had to be r...Aquaculture plays a major role in providing the needed protein. However, there have been reports of negative impacts of shrimp farming which include environmental pollution. Therefore, shrimp pond effluent had to be retained for treatment. Treatment in tanks showed good improvement in water quality but in sedimentation ponds it may not be the case. Therefore, the objective of this study was to determine the water quality of effluent retained in sedimentation pond for a duration of 76 hours. Results show that water quality at 1/3 depth was better than 2/3 depth. There was an improvement in water quality with reductions of TSS, BOD5, COD, nitrate-N, nitrite-N, SRP and TP ranging from 25-52% except for DO and TAN. In addition, there was fluctuation of each parameter during the duration of study. It is important to monitor the water quality prior to the release of effluent so that it coincides with low nutrients and acceptable DO and partial release of the top 1/3 portion is recommended. There is a limit on the reduction achievable by sedimentation ponds likely due to processes occurring in the sediment. For higher reductions, other methods of effluent management and recovery of nutrients have to be considered.展开更多
The Malaysian mahseer(Tor tambroides),one of the most valuable freshwater fish in the world,is mainly targeted for human consumption.The mitogenomic data of this species is available to date,but the genomic informatio...The Malaysian mahseer(Tor tambroides),one of the most valuable freshwater fish in the world,is mainly targeted for human consumption.The mitogenomic data of this species is available to date,but the genomic information is still lacking.For the first time,we sequenced the whole genome of an adult fish on both Illumina and Nanopore platforms.The hybrid genome assembly had resulted in a sum of 1.23 Gb genomic sequence from the 44,726 contigs found with 44 kb N50 length and BUSCO genome completeness of 87.6%.Four types of SSRs had been detected and identified within the genome with a greater AT abundance than that of GC.Predicted protein sequences had been functionally annotated to public databases,namely GO,KEGG and COG.A maximum likelihood phylogenomic tree containing 52 Actinopterygii species and one Sarcopterygii species as outgroup was constructed,providing first insights into the genome-based evolutionary relationship of T.tambroides with other ray-finned fish.These data are crucial in facilitating the study of population genomics,species identification,morphological variations,and evolutionary biology,which are helpful in the conservation of this species.展开更多
The study compared the antibacterial activity of synthesized ZnO nanoparticles(NPs)from fresh leaf and fresh stem bark aqueous extracts of Carica papaya against five selected microbes:Staphylococcus aureus,(Gram posit...The study compared the antibacterial activity of synthesized ZnO nanoparticles(NPs)from fresh leaf and fresh stem bark aqueous extracts of Carica papaya against five selected microbes:Staphylococcus aureus,(Gram positive(+ve)),Escherichia coli(Gram negative(-ve)),Acinetobacter baumanni(Gram-ve),Exiguobacterium aquaticum(Gram+ve),and Klebsielia pneumonia(Gram+ve).The morphological features of the biosynthesized ZnO NPs were analyzed using transmission electron microscope(TEM)and scanning electron microscope(SEM);the Fourier-transform infrared spectrometer(FTIR)technique was used to observe the surface functional groups.The experimental results indicated that ZnO NPs were successfully synthesized using modified hydrothermal technique,which showed agglomerated flake-like or petal-like shapes with the organic extract surrounding the formed particles.The average particle size of the synthesized ZnO nanoparticles determined by SEM ranged between 54-97 nm with the width and length of the petal-like structures been 30 nm and 62 nm respectively.The average ZnO NPs from fresh stem bark extract of Carica papaya with higher concentrations(100-1000 ppm)demonstrated a higher antibacterial activity than the fresh leaf extracts.On the other hand,ZnO NPs from fresh leaf extracts of lower concentrations(25-50 ppm)rather showed a suitable result than the fresh stem bark.In general,ZnO NPs showed a positive antibacterial result towards the selected microbes.This shows that,the synthesized ZnO NP can be a substitute to chemical methods.展开更多
Vibrio spp.is a group of heterotrophic bacteria that are ubiquitous in marine habitats,with various ecological and clinical importance.This study investigated the environmental factors that regulate Vibrio spp.dynamic...Vibrio spp.is a group of heterotrophic bacteria that are ubiquitous in marine habitats,with various ecological and clinical importance.This study investigated the environmental factors that regulate Vibrio spp.dynamics in various tropical marine habitats,including nearshore(an estuary and a coastal beach)and offshore transects located northwest and southeast of Peninsular Malaysia,while focusing on the distribution of attached and free-living Vibrio spp.,population growth,and community composition.The results showed that>85%of the Vibrio spp.in nearshore waters occurred in attached form and correlated positively to total suspended solids(TSS)and Chlorophyll a(Chl a)concentrations.On the other hand,Vibrio spp.growth rates were positively correlated to dissolved organic carbon(DOC)concentrations,but negatively correlated to total bacterial counts,likely due to resource competition.In addition,high-throughput sequencing of 16S rRNA V3-V4 region showed that Vibrio spp.in these tropical waters contributed<1−18%of the whole bacterioplankton community,and the six major Vibrio spp.taxa were V.alginolyticus group,V.brasiliensis,V.caribbeanicus,V.hepatarius group,V.splendidus group and V.thalassae.db-RDA(cumulative variance explicated=93.53%)further revealed the influence of TSS,DOC,and dissolved organic nitrogen(DON)to the Vibrio spp.community profiles.The study highlighted the importance of suspended solids(TSS and Chl a)and dissolved organic nutrients(DOC and DON)towards Vibrio spp.dynamics in tropical marine waters.展开更多
In this study,we aim to fabricate a silver nanoparticles(Ag NPs)based electrochemical biosensor for Japanese Encephalitis virus antigen detection.Ag NPs were deposited onto screen-printed carbon electrode(SPCE)and the...In this study,we aim to fabricate a silver nanoparticles(Ag NPs)based electrochemical biosensor for Japanese Encephalitis virus antigen detection.Ag NPs were deposited onto screen-printed carbon electrode(SPCE)and the electrochemical properties of the Ag NPs modified SPCE were investigated via electrochemical impedance spectroscopy(EIS)and cyclic voltammetry(CV).It was observed that the deposition of Ag NPs onto electrode surface has significantly enhanced the conductivity up to 20.5%than that of bare SPCE.The EIS data indicated limit of detection(LOD)of 2.60 ng/mL(at S/N=3)towards JEV antigen,with an analysis assay time of 20 min.This presented Ag NPs modified SPCE has demonstrated a promising and rapid alternative to conventional biosensing techniques towards JEV antigen.展开更多
基金Universiti Malaysia Sarawak for the support of this research。
文摘In the Peninsular Malaysia and Northern Borneo island of Malaysia, various rich indigenous leafy vegetables and fruits grow and contribute to the nutritional and dietary values of the population. They have high water contents, thus, naturally vulnerable to rapid food spoilage. Food preservation and processing play a vital role in the inhibition of food pathogens in fruits and vegetables that are prevalent in Malaysia. Lactic acid fermentation is generally a local-based bioprocess, among the oldest form and well-known for food-processing techniques among indigenous people there. The long shelf life of fermented vegetables and fruits improves their nutritional values and antioxidant potentials. Fermented leaves and vegetables can be utilized as a potential source of probiotics as they are host for several lactic acid bacteria such as Lactobacillus confusus, Weissella paramesenteroides, Enterococcus faecalis, Lactobacillus plantarum, Lactobacillus buchneri, Lactobacillus paracasei, Lactobacillus pentosus, Pediococcus acidilactici, Pediococcus pentosaceus and Leuconostoc mesenteroides. These strains may be more viable in metabolic systems whereby they can contribute to a substantial increase in essential biologically active element than industrial starter cultures. This review is aimed to address some essential fermented fruits and vegetables in Malaysia and their remarkable reputations as a potential sources of natural probiotics.
基金Funded by Universiti Malaysia Sarawak(UNIMAS)research grant E14052-F07-49-792/2011(2)scholarship to the postgraduate by Universiti Teknologi MARA(UITM)
文摘Objective:To investigate antioxidant and antimicrobial activities of two plant species,Litsea elliptica(L elliptica) and Litsea resinosa(L resinosa).Methods:In vitro method-2,2-diphenyl-1-picrylhydrazyl radical scavenging assay was conducted for antioxidant activity detennination while antimicrobial assay consisted of agar well diffusion assay and mycelial radial growth assay.Results:Methanol extracts of root and stem of L elliptica and L resinosa exhibited the highest antioxidant activity with EC_(50)of 23.99,41.69,11.22 and 33.48 mg/l.respectively.All methanol extracts of L resinosa as well as root extracts from L elliptica showed significant scavenging activity.Hexane extract from stem of L resinosa presented the largest inhibition zone in Gramnegative bacteria Pseudomonas aeruginosa and Escherichia coli while chloroform extract from inner bark of L resinosa showed major inhibition towards Gram-positive bacteria Bacillus subtilis.Essential oils from the root of both species showed significant antifungal activities which are 80.11%and 66.85%respectively.Conclusions:Overall,methanol extracts from root and stem of both species showed antioxidant activity comparable to standard butylated hydroxytoluene.Extracts from L resinosa demonstrated stronger antimicrobial properties compared to that from L elliptica.
文摘Developments along the Santubong River basin may have an impact on the aquatic ecosystem. To determine the impacts of activities on the water quality, ten stations were selected for water quality study over 9 months. Results show that salinity increases from 14.0 PSU upstream to 30.4 PSU downstream. Lowest DO range was 2.3-4.1 mg/L. TSS ranged was 20-135 mg/L and the highest was observed near construction and residential areas, the second and third highest near shrimp culture discharge areas. BOD5 was the highest near construction and residential areas. BOD5 of a station near shrimp culture was not significantly different from the residential areas. Two stations near shrimp culture site also recorded the highest Chl-a. The highest ammonia-nitrogen, nitrite-nitrogen and reactive phosphorus were observed at stations near shrimp farm sites whereas nitrate-nitrogen was the highest near construction and residential areas. Cage culture site showed the highest phosphorus and second highest nitrite-nitrogen and ammonia-nitrogen. This study showed that TSS and BOD5 were elevated near residential and construction areas and nutrients were elevated near shrimp farm sites resulting in algal bloom. Therefore, it is recommended that residential and shrimp farm discharge be treated to acceptable quality before discharge to protect the aquatic resources.
基金the financial support under the Fundamental Research Grant Scheme[FRGS/SG01(01)/1204/2014(05)]
文摘The use of nanosized titanium dioxide（TiO2） and zinc oxide（ZnO） in the suspension form during treatment makes the recovering and recycling of photocatalysts difficult.Hence,supported photocatalysts are preferred for practical water treatment applications.This study was conducted to investigate the efficiency of calcium alginate（CaAlg） beads that were immobilized with hybrid photocatalysts,TiO2/ZnO to form TiO2/ZnO-CaAlg.These immobilized beads,with three different mass ratios of TiO2：ZnO（1：1,1：2,and 2：1） were used to remove Cu（Ⅱ） in aqueous solutions in the presence of ultraviolet light.These beads were subjected to three cycles of photocatalytic treatment with different initial Cu（Ⅱ） concentrations（10-80 ppm）.EDX spectra have confirmed the inclusion of Ti and Zn on the surface of the CaAlg beads.Meanwhile,the surface morphology of the beads as determined using SEM,has indicated differences of before and after the photocatalytic treatment of Cu（Ⅱ）.Among all three,the equivalent mass ratio TiO2/ZnO-CaAlg beads have shown the best performance in removing Cu（Ⅱ） during all three recycling experiments.Those TiO2/ZnO-CaAlg beads have also shown consistent removal of Cu,ranging from 7.14-52.0 ppm（first cycle） for initial concentrations of10-80 ppm.In comparison,bare CaAlg was only able to remove 6.9-48 ppm of similar initial Cu concentrations.Thus,the potential use of TiO2/ZnO-CaAlg beads as environmentally friendly composite material can be further extended for heavy metal removal from contaminated water.
基金supported by Universiti Malaysia Sarawak (UNIMAS) through the award of a special fundamental research grant 01(K03)/557/2005(56)
文摘Stable colloidal suspension of magnetite/starch nanocomposite was prepared by a facile and aqueous-based chemical precipitation method, Magnetite/carbon nanocomposite thin films were subsequently formed upon carbonization of the starch component by heat treatment under controlled conditions. The initial content of native sago starch as the carbon source was found to affect the microstructure and electrochemical properties of the resulted magnetite/carbon nanocomposite thin films, A specific capacitance of 124 F/g was achieved for the magnetite/carbon nanocomposite thin films as compared to that of 82 F/g for pure magnetite thin films in Na2SO4 aqueous electrolyte.
文摘Five new organotin(IV) complexes of ortho-vanillin-2-hydrazinopyridine hydrazone with formula [RnSnCl4–n(VHP)] [R = Me2, n = 2 (2);R = Ph2, n = 2 (3);R= nBu2, n = 2 (4);R = nBu, n = 2 (5) and R = 1, n = 0 (6)] have been synthesized by direct reaction of ortho-vanillin-2-hydrazinopyridine hydrazone [(VHP), (1)], base and organotin(IV) chloride(s) in absolute methanol. The hydrazone ligand [(VHP), (1)] and its organotin(IV) complexes (2-6) have been characterized by UV-Visible, FT-IR and 1H NMR spectral studies. Spectroscopic data suggested that in the complexes (2-4), the ligand (1) acted as a neutral bidentate ligand and is coordinated to the tin(IV) atom via the azomethine nitrogen and pyridyl nitrogen atoms, whereas the ligand (1) acted as a uninegative tridentate ligand and coordinated to the tin(IV) atom through phenolic-O, azomethine-N and pyridyl-N atoms in complexes (5-6). The toxicity of the ligand (1) and its organotin (IV) complexes (2-6) were determined against Artemia salina. Organotin(IV) complexes showed moderate activity against Artemia salina. The ligand (1) and its organotin(IV) complexes (2-6) were also tested against four types of bacteria namely Bacillus cereus, Staphylococcus aureus, Escherichia coli and Enterobacter aerogenes. All organotin(IV) complexes and the free ligand (1) showed better antibacterial activities against bacteria. Among the organotin(IV) complexes (2-6), diphenyltin(IV) complex (3) showed higher activity against the four types of bacteria.
文摘Sediment is a sink for organic materials, nutrients and heavy metals and sediment condition affects the overlying water Though Serin River is a source of drinking water, agricultural and waste disposal activities in the watershed may impact the sediment of the river. Therefore, the objective of this study was to investigate the organic matter, nutrients and heavy metals in the sediment of the Serin River. Five stations were selected for sediment sample collection. Results of the study show that organic matter （OM） ranged from 0.7% to 5.9%, TP was 100 -366 （mg/kg）, TAN was 16-141 （mg/kg）, TON was 550-3019（mg/kg）, and TKN was 566-3160 （mg/kg）. Sediment oxygen demand （SOD20） ranged from 5.6 to 14.2 （g O2/m^2/d）. Among the five stations OM, TKN, and SOD of the sediment were second highest at the two stations downstream of animal （fish, chicken and pig） farming. TP and TAN were the second highest at the station downstream of fish farming and third highest at the station downstream of pig farming. Zn, Cu and Cd ranged from 132-357 （mg/kg）, 26.7-96.7 （mg/kg） and 4.0-19.3（mg/kg）. According to USEPA guideline, sediments at four stations were heavily polluted with Zn, Cu and Cd whereas the station that was farthest upstream, near a village, was slightly polluted with Zn and Cu. This study indicates that animal farming has an impact on the organic matter content, nutrients （N and P）, oxygen demand and heavy metals of the sediment. Motor vehicles and discarded e-waste also contributed to the heavy metals in the sediment. Farm effluents and storm water should be treated and e-waste recycled to protect the water quality of the river for its designated use.
文摘Shrimp aquaculture is an important source of revenue for the state of Sarawak, Malaysia. However, there were concerns on the impact of shrimp farming on the mangrove ecosystem due to the discharge of shrimp pond water to the surrounding environment and potential self-pollution through the intake of surrounding water for the shrimp ponds. Therefore, the objectives of this study were to determine the water quality of the harvesting pond water and quantify the pollutants loadings. Samplings were conducted in three ponds and three channels near the pond outflow in a commercial shrimp farm during complete draining of water at harvest. Results indicated that TSS and Chl-a were high in both the ponds and channels. Total ammonia-nitrogen was the predominant form of the inorganic nitrogen and the mean values in both the ponds and channels were more than 1 mg/L which exceeded the maximum recommended for fish. Therefore, the water quality of the ponds and channel indicate that pond effluent should not be discharged directly into the surrounding environment but treated and nutrients recovered. Loads of total suspended solids, BODs, inorganic nitrogen, ammonia nitrogen, soluble reactive phosphorus and Chl-a of the effluent were quantified.
文摘Pollen viability study on Piper colubrinum Link. carried out to develop interspecific hybridization between P. nigrum L. and P. colubrinum Link.. This plant has good potential as a donor plant in breeding programme for Phytophthora to foot rot resistance in the cultivated species, P. nigrum. This project was carried out to reveal the optimum time to collect pollen of P. colubrinum for artificial pollination. Through this study, anther dehiscence was proved occurred around 9 am. Based on the result obtained from study on the time of anther dehiscence, the pollen was classified into five stages for testing on the viability, i.e., stage 1, before anther dehiscence, i.e., around 7 am （pollen obtained by crushing on the anther）; stage 2： immediately after anther dehiscence, i.e., around 9 am; stage 3： two hours after anther dehiscence, i.e., around 11 am; stage 4： four hours after anther dehiscence, i.e., around 1 pm; and stage 5： six hours after anther dehiscence, i.e., around 3 pm. Data obtained from pollen germination and pollen tube growth study showed that pollen of P. colubrinum was the most viable at two hours after anther dehiscence and onward. It was also proved that the viability can be maintained up to at least eight hours. Pollen obtained before anther dehiscence by crushing on the anther was found less viable with lower percentage of pollen germination and retarded pollen tube growth. In other words, the experiment enlightened that artificial pollination between P. nigrum L. and P. colubrinum Link was ideally to be carded out approximately starting from 11 am until 5 pm, considering the viability of pollen ofP. colubrinum.
基金supported by the Sime Darby Foundation(Grant code:P23 071000490001)
文摘Objective:To demonstrate a noninvasive large mammalian genetic sampling method using blood meal obtained from a tabanid fly.Methods:Blood meal was recovered from the abdomen of an engorged tabanid fly(Haematopota sp.)which was captured immediately after biting a Sumatran rhino in captivity.The blood was applied on to a Whatman FTAblood card.Subsequent laboratory work was conducted to extract,amplify and sequence the DNA from the sample.Validation was done by sampling the hair follicles and blood samples from the rhinoceros and subjecting it to the same laboratory process.Results:BLAST search and constructed phylogenetic trees confirmed the blood meal samples were indeed from the rhino.Conclusions:This method could be used in the field application to noninvasively collect genetic samples.Collection of tabanids and other haematophagous arthropods(e.g.mosquitoes and ticks)and other blood-sucking parasites(e.g.leeches and worms)could also provide information on vector-borne diseases.
文摘Aquaculture plays a major role in providing the needed protein. However, there have been reports of negative impacts of shrimp farming which include environmental pollution. Therefore, shrimp pond effluent had to be retained for treatment. Treatment in tanks showed good improvement in water quality but in sedimentation ponds it may not be the case. Therefore, the objective of this study was to determine the water quality of effluent retained in sedimentation pond for a duration of 76 hours. Results show that water quality at 1/3 depth was better than 2/3 depth. There was an improvement in water quality with reductions of TSS, BOD5, COD, nitrate-N, nitrite-N, SRP and TP ranging from 25-52% except for DO and TAN. In addition, there was fluctuation of each parameter during the duration of study. It is important to monitor the water quality prior to the release of effluent so that it coincides with low nutrients and acceptable DO and partial release of the top 1/3 portion is recommended. There is a limit on the reduction achievable by sedimentation ponds likely due to processes occurring in the sediment. For higher reductions, other methods of effluent management and recovery of nutrients have to be considered.
基金This work was fully funded by Sarawak Research and Development Council through the Research Initiation Grant Scheme with grant number RDCRG/RIF/2019/13 awarded to H.H.Chung.
文摘The Malaysian mahseer(Tor tambroides),one of the most valuable freshwater fish in the world,is mainly targeted for human consumption.The mitogenomic data of this species is available to date,but the genomic information is still lacking.For the first time,we sequenced the whole genome of an adult fish on both Illumina and Nanopore platforms.The hybrid genome assembly had resulted in a sum of 1.23 Gb genomic sequence from the 44,726 contigs found with 44 kb N50 length and BUSCO genome completeness of 87.6%.Four types of SSRs had been detected and identified within the genome with a greater AT abundance than that of GC.Predicted protein sequences had been functionally annotated to public databases,namely GO,KEGG and COG.A maximum likelihood phylogenomic tree containing 52 Actinopterygii species and one Sarcopterygii species as outgroup was constructed,providing first insights into the genome-based evolutionary relationship of T.tambroides with other ray-finned fish.These data are crucial in facilitating the study of population genomics,species identification,morphological variations,and evolutionary biology,which are helpful in the conservation of this species.
基金supported by Universiti Malaysia Sarawak,Tun Openg Chair,with Research Grant Code:F07/TOC/1738/2018.
文摘The study compared the antibacterial activity of synthesized ZnO nanoparticles(NPs)from fresh leaf and fresh stem bark aqueous extracts of Carica papaya against five selected microbes:Staphylococcus aureus,(Gram positive(+ve)),Escherichia coli(Gram negative(-ve)),Acinetobacter baumanni(Gram-ve),Exiguobacterium aquaticum(Gram+ve),and Klebsielia pneumonia(Gram+ve).The morphological features of the biosynthesized ZnO NPs were analyzed using transmission electron microscope(TEM)and scanning electron microscope(SEM);the Fourier-transform infrared spectrometer(FTIR)technique was used to observe the surface functional groups.The experimental results indicated that ZnO NPs were successfully synthesized using modified hydrothermal technique,which showed agglomerated flake-like or petal-like shapes with the organic extract surrounding the formed particles.The average particle size of the synthesized ZnO nanoparticles determined by SEM ranged between 54-97 nm with the width and length of the petal-like structures been 30 nm and 62 nm respectively.The average ZnO NPs from fresh stem bark extract of Carica papaya with higher concentrations(100-1000 ppm)demonstrated a higher antibacterial activity than the fresh leaf extracts.On the other hand,ZnO NPs from fresh leaf extracts of lower concentrations(25-50 ppm)rather showed a suitable result than the fresh stem bark.In general,ZnO NPs showed a positive antibacterial result towards the selected microbes.This shows that,the synthesized ZnO NP can be a substitute to chemical methods.
基金supported by the Ministry of Higher Education Malaysia(HiCoE grant Phase I fund IOES-2014D and IOES-2014E,and Phase II fund IOES-2014C)the National Natural Science Foundation of China(Contract No:41961144022)also by Universiti Malaya(PG279-2016A and RU009F-2020).
文摘Vibrio spp.is a group of heterotrophic bacteria that are ubiquitous in marine habitats,with various ecological and clinical importance.This study investigated the environmental factors that regulate Vibrio spp.dynamics in various tropical marine habitats,including nearshore(an estuary and a coastal beach)and offshore transects located northwest and southeast of Peninsular Malaysia,while focusing on the distribution of attached and free-living Vibrio spp.,population growth,and community composition.The results showed that>85%of the Vibrio spp.in nearshore waters occurred in attached form and correlated positively to total suspended solids(TSS)and Chlorophyll a(Chl a)concentrations.On the other hand,Vibrio spp.growth rates were positively correlated to dissolved organic carbon(DOC)concentrations,but negatively correlated to total bacterial counts,likely due to resource competition.In addition,high-throughput sequencing of 16S rRNA V3-V4 region showed that Vibrio spp.in these tropical waters contributed<1−18%of the whole bacterioplankton community,and the six major Vibrio spp.taxa were V.alginolyticus group,V.brasiliensis,V.caribbeanicus,V.hepatarius group,V.splendidus group and V.thalassae.db-RDA(cumulative variance explicated=93.53%)further revealed the influence of TSS,DOC,and dissolved organic nitrogen(DON)to the Vibrio spp.community profiles.The study highlighted the importance of suspended solids(TSS and Chl a)and dissolved organic nutrients(DOC and DON)towards Vibrio spp.dynamics in tropical marine waters.
基金Financial support by the Ministry of Education(MOE)through the Exploratory Research Grant S cheme(ERGS),Grant no.ERGS/STG05(01)/1005/2013(02),F07/(DPP01)/1121/2014graduate scholarships from MyBrain15(MyMaster)Programme,Universiti Malaysia Sarawak Zamalah,MyBrain15(MyPhD)Programme are gratefully acknowledged.
文摘In this study,we aim to fabricate a silver nanoparticles(Ag NPs)based electrochemical biosensor for Japanese Encephalitis virus antigen detection.Ag NPs were deposited onto screen-printed carbon electrode(SPCE)and the electrochemical properties of the Ag NPs modified SPCE were investigated via electrochemical impedance spectroscopy(EIS)and cyclic voltammetry(CV).It was observed that the deposition of Ag NPs onto electrode surface has significantly enhanced the conductivity up to 20.5%than that of bare SPCE.The EIS data indicated limit of detection(LOD)of 2.60 ng/mL(at S/N=3)towards JEV antigen,with an analysis assay time of 20 min.This presented Ag NPs modified SPCE has demonstrated a promising and rapid alternative to conventional biosensing techniques towards JEV antigen.
