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  1. A review on sperata aor (Hamilton, 1822), a popular food Ffish of indian subcontinent
    Sandipan Gupta
    Sains Malaysiana, 2015;44:1217-1222.
    Sperata aor is a freshwater catfish of Bagridae family which is distributed throughout Indian subcontinent including India, Bangladesh, Pakistan, Nepal and Myanmar. It is a popular food fish due to its good taste and high nutritional value. Recently it has also made its entry in domestic ornamental fish markets of India and has been reported to have moderate export price too. Earlier, few works on different aspects of its morphology and biology have been carried out but no consolidated review is available on these aspects. Therefore, the current work was done to sum up all available information on these aspects to fill the information gap that will be beneficial to its future fishery. Considering all available information, knowledge on food and feeding habit of this fish species is satisfactory, except detail information on spatial variation of its breeding periodicity, proper information on other aspects are still lacking. No work has been conducted to examine its captive culture potential or for induced breeding. Further work should be done to explore its future fishery.
    Matched MeSH terms: Fresh Water
  2. Application of thermo-separating aqueous two-phase system in extractive bioconversion of polyhydroxyalkanoates by Cupriavidus necator H16
    Leong YK, Show PL, Lan JC, Krishnamoorthy R, Chu DT, Nagarajan D, et al.
    Bioresour Technol, 2019 Sep;287:121474.
    PMID: 31122870 DOI: 10.1016/j.biortech.2019.121474
    Polyhydroxyalkanoates (PHAs), a family of biodegradable and renewable biopolymers show a huge potential as an alternative to conventional plastics. Extractive bioconversion (in situ product recovery) is a technique that integrates upstream fermentation and downstream purification. In this study, extractive bioconversion of PHAs from Cupriavidus necator H16 was performed via a thermo-separating aqueous two-phase system to reduce the cost and environmental impacts of PHAs production. Key operating parameters, such as polymer concentration, temperature, and pH, were optimized. The strategy achieved a yield and PF of 97.6% and 1.36-fold, respectively at 5% EOPO 3900 concentration, 30 °C fermentation temperature and pH 6. The PHAs production process was also successfully scaled up in a 2 L bioreactor. To the best of our knowledge, this is the first report on extractive fermentation of PHAs from Cupriavidus necator utilizing a thermo-separation system to achieve a better productivity and purity of the target product.
    Matched MeSH terms: Water
  3. Mechanical, thermal and chemical resistance of epoxidized natural rubber toughened polylactic acid blends
    Mat Uzir Wahi, Azman Hassan, Akos Noel Ibrahim, Nurhayati Ahmad Zawawi, Kunasegeran K
    Sains Malaysiana, 2015;44:1615-1623.
    Polylactic acid (PLA)/Epoxidized natural rubber (ENR-50) blends were prepared by melt extrusion followed by injection
    molding to fabricate the test samples. The effect of ENR-50 loadings on the morphological, mechanical, chemical
    resistance and water absorption properties of the blends were studied using standard methods. The toughness of the
    blend improved with ENR loading up to 20 wt. % but flexural and tensile strength decreased. The balanced mechanical
    properties were obtained at 20 wt. % ENR-50 loading. SEM showed good distribution and increased ENR particle size
    as ENR content increased from 10 to 30 wt. %. The differential scanning calorimeter (DSC) showed a steady drop in
    crystallization temperature (Tc
    ) as ENR content increases while the glass transition temperature (Tg
    ) remained unchanged.
    Water absorption was observed to increase with ENR loadings. Increase in ENR content was also observed to reduce the
    chemical resistance of the blends.
    Matched MeSH terms: Water
  4. Streamlined life cycle CO2 emission assessment of sewage treatment in Taiwan
    Chang Ys
    Sains Malaysiana, 2015;44:1715-1720.
    Sewage treatment is an important issue in a country for public health and environmental protection. The treatment
    process not only consumes energy but also emits CO2
    . In this research, the idea of streamlined life cycle assessment was
    applied. The CO2
    emission from sewage treatment was assessed from direct energy consumption of four major sewage
    treatment plants in Taiwan. The results showed that the CO2
    emission at in-plant sewage treatment stage takes more
    than 95% of total CO2
    emission for most plants. The results suggested that CO2
    emission of sewage treatment can be
    calculated from energy consumption at in-plant sewage treatment stage to simplify the calculation. The CO2
    emission
    of sewage treatment was then assessed from sewage plants in Taiwan using in-plant electricity consumption. The unit
    CO2
    emission of sewage treatment in Taiwan is 0.216 kg-CO2
    /m3
    . This database will be an important reference for water
    resource research and future government environmental policies.
    Matched MeSH terms: Water
  5. Oligochaeta sebagai Penunjuk Biologi Ekosistem Lentik
    Ahmad A.M., Shuhaimi Othman, Barzani-Gasim M., Mohd Alwi N.
    Sains Malaysiana, 2004;33.
    A preliminary study was conducted to determine the presence and abundance of aquatic worms in Lake Chini ecosystem, Pahang (Gumum Sea). Samplings were conducted twice in 2000. Water quality analysis was conducted to determine the water quality of the lake at the sampling locations. Results showed that nutrient levels in the water body was low and values for other physical parameters such as temperature, pH and conductivity suggested that Gumum Sea in Lake Chini is free from pollution. According to Malaysian interim river classification (Department of Environment, Malaysia), Lake Chini falls within class I to III which indicates good water quality. Annelida was the most dominant phylum found in the study area, which comprise of two major families namely Naididae and Tubificidae. This phylum contributed about 59% of the total individuals sampled and the rests were Arthropoda and Plathyhelmintes. Naididae was the most dominat family and contributed over 98% of the toal population of aquatic worms present. Dero, Aulophorus, Pristina, Branchiodrilus and Ripistes were amongst the dominant genera and showed good adaptations to the pollution free ecosystem of Lake Chini.
    Matched MeSH terms: Water Quality
  6. Pm2.5 and associated ionic species in a sub-urban coastal area of Kuala Terengganu, Southern South China Sea (Malaysia)
    Norhayati Mohd Tahir, Meikee Koh, Suhaimi Suratman
    Sains Malaysiana, 2013;42:1065-1072.
    PM2.5 mass concentration and associated water-soluble ionic species in a sub-urban coastal area of Kuala Terengganu, Malaysia were investigated intermittently from year 2006 to 2009. A total of 78 weekly PM2.5 samples were analyzed. The mass concentration of PM2.5 exhibited annual, seasonal and diurnal variations. Temporal distributions of rainfall, sporadic haze episodes and local air flow (sea breeze circulation) were factors controlling PM2.5 mass variations in the study area. Although the PM2.5 concentrations were increased during haze episodes in 2006 (August and October) and2007 (October), their concentrations however, were still within the international guidelines. The average concentration of individual ions was in decreasing trend; SO42-> NH4+> K+> Na+> NO3-> Cl-> Ca2+. The concentrations of SO42- and NH4+ accounted for > 70% of the water-soluble aerosol mass. More than 80% of ionic species associated with PM2.5 are from non-marine sources. Major processes affecting the ionic composition of PM2.5 are biomass burning, crustal loading and sea spray. Air quality mitigation strategies should focus on anthropogenic activities emitting SO2, which promotes aerosol SO42- formation.
    Matched MeSH terms: Water
  7. Microbial fuel cells using mixed cultures of wastewater for electricity generation
    Zain S, Roslani N, Hashim R, Anuar N, Suja F, Basri N, et al.
    Sains Malaysiana, 2011;40.
    Fossil fuels (petroleum, natural gas and coal) are the main resources for generating electricity. However, they have been major contributors to environmental problems. One potential alternative to explore is the use of microbial fuel cells (MFCs), which generate electricity using microorganisms. MFCs uses catalytic reactions activated by microorganisms to convert energy preserved in the chemical bonds between organic molecules into electrical energy. MFC has the ability to generate electricity during the wastewater treatment process while simultaneously treating the pollutants. This study investigated the potential of using different types of mixed cultures (raw sewage, mixed liquor from the aeration tank & return waste activated sludge) from an activated sludge treatment plant in MFCs for electricity generation and pollutant removals (COD & total kjeldahl nitrogen, TKN). The MFC in this study was designed as a dual-chambered system, in which the chambers were separated by a NafionTM membrane using a mixed culture of wastewater as a biocatalyst. The maximum power density generated using activated sludge was 9.053 mW/cm2, with 26.8% COD removal and 40% TKN removal. It is demonstrated that MFC offers great potential to optimize power generation using mixed cultures of wastewater.
    Matched MeSH terms: Waste Water
  8. Assessment of heavy metal in self-caught saltwater fish from Port Dickson Coastal Water (Malaysia)
    Sarva Mangala Praveena, Caryn Liew Suet Lin
    Sains Malaysiana, 2015;44:91-99.
    Freshwater fish has been studied and reported numerously. However, little attention has been made and limited studies available on local marine fish in Malaysia. Thus, in this study, concentrations of heavy metals (Cd, Cr, Pb and Cu) were studied in four major local marine fish Megalaspis cordyla (hardtail scad), Rastrelliger kanagurta (Indian mackerel), Selaroides leptolepis (yellowstripe scad) and Sardinella fimbriata (fringescale sardinella). The study was also intended to estimate potential health risk assessment from these heavy metals to the consumption of fish and assess maximum allowable fish consumption rate. The range of heavy metal concentrations were 0.053-0.096 mg/kg for Cd, 1.16-2.34 mg/kg for Cr, 8.34-12.44 mg/kg for Pb and 1.40-3.21 mg/kg for Cu in four major self-caught saltwater fish. Heavy metal levels of Cd and Cu in the local marine fish from Port Dickson are below the limit enforced by Food Regulations (1985) while the levels of Cr and Pb have exceeded the limit. Potential health risks associated with Cd, Cr, Cu and Pb were assessed based on target hazard quotients. HQ values calculated for Cd, Cr and Cu were less than 1, thus indicate that no adverse effects while HQ values for Pb exceeded 1 for all the fish species assessed with the exception of Megalaspis spp and Sardinella sppa. Cr was the highest while Pb concentrations were the lowest in all the studied fish samples for maximum allowable fish consumption rate. A long term monitoring program is crucial to be done in coastal areas with high consumption of local marine fish along Port Dickson to obtain real consumption rates and other cofounders factors in local population.
    Matched MeSH terms: Fresh Water
  9. Assessment of the potential allelopathic effects of pennisetum purpureum schumach. on the germination and growth of eleusine indica (l.) gaertn.
    Ismail B, Chuah T, Tan P
    Sains Malaysiana, 2015;44:269-274.
    Pennisetum purpureum Schumach. is a weed that is currently spreading rapidly to many parts of the world particularly tropical countries. The abundance of P. purpureum in Malaysia is presently a serious problem. A study was conducted to investigate and evaluate the potential allelopathic effects of P. purpureum on Eleusine indica L. Gaertn. using the aqueous leaf extract and plant debris incorporated into the soil. Low concentrations of the P. purpureum aqueous extract (2%) and debris incorporated into the soil (25/500 g) inhibited germination and seedling growth of the bioassay species (E. indica) by >80%. The responses of the bioassay species to the aqueous extract and debris-incorporated soil were concentration dependent. The aqueous extract had higher total phenolic content compared to that from the debris incorporated soil, indicating the presence of certain phytotoxic compounds in the leaf debris and leaf extracts.
    Matched MeSH terms: Water
  10. Optimizing the performance of a paper mill effluent treatment
    Moetaz Elsergany, Amimul Ahsan, Md. Maniruzzaman A. Aziz
    Sains Malaysiana, 2015;44:101-106.
    The paper making industry is characterized by high rate of water consumption and hence high rate of wastewater generation. The purpose of this research was to assess and optimize the existing complete mix activate sludge treatment plant that is used to treat the high strength paper mill effluent with the highest possible efficiency at a reasonable cost. The collected paper mill wastewater is equalized in an equalization tank before being pumped to the treatment plant. The treatment plant includes chemical treatment unit, complete mix activated sludge and granular media filtration unit. The results showed that effluent of a chemical treatment unit was found to be relatively similar to the laboratory simulated plain sedimentation unit. It can be concluded that addition of chemical coagulant can be eliminated with an overall saving of chemical addition costs. The complete mixing activated sludge achieved good removal of biochemical oxygen demand (BOD) and chemical oxygen demand (COD). Furthermore, the results showed that the plant is operated under low BOD:P ratio. The treatment efficiency of the plant can be improved by increasing the phosphorous dose to the plant to have BOD:P ratio of 100:0.5 to 100:1. It was found that 50% of the treated effluent is recycled to the manufacturing process, however this percentage can be increased through proper plant optimization and control of nutrient addition to the activated sludge unit.
    Matched MeSH terms: Waste Water
  11. Mapping the cumulative impacts of long-term mining disturbance and progressive rehabilitation on ecosystem services
    Wang Z, Lechner AM, Yang Y, Baumgartl T, Wu J
    Sci Total Environ, 2020 May 15;717:137214.
    PMID: 32062237 DOI: 10.1016/j.scitotenv.2020.137214
    Open-cut coal mining can seriously disturb and reshape natural landscapes which results in a range of impacts on local ecosystems and the services they provide. To address the negative impacts of disturbance, progressive rehabilitation is commonly advocated. However, there is little research focusing on how these impacts affect ecosystem services within mine sites and changes over time. The aim of this study was to assess the cumulative impacts of mining disturbance and rehabilitation on ecosystem services through mapping and quantifying changes at multiple spatial and temporal scales. Four ecosystem services including carbon sequestration, air quality regulation, soil conservation and water yield were assessed in 1989, 1997, 2005 and 2013. Disturbance and rehabilitation was mapped using LandTrendr algorithm with Landsat. We mapped spatial patterns and pixel values for each ecosystem service with corresponding model and the landscape changes were analyzed with landscape metrics. In addition, we assessed synergies and trade-offs using Spearman's correlation coefficient for different landscape classes and scales. The results showed that carbon sequestration, air quality regulation and water yield services were both positively and negatively affected by vegetation cover changes due to mined land disturbance and rehabilitation, while soil conservation service were mainly influenced by topographic changes. There were strong interactions between carbon sequestration, air quality regulation and water yield, which were steady among different spatial scales and landscape types. Soil conservation correlations were weak and changed substantially due to differences of spatial scales and landscape types. Although there are limitations associated with data accessibility, this study provides a new research method for mapping impacts of mining on ecosystem services, which offer spatially explicit information for decision-makers and environmental regulators to carry out feasible policies, balancing mining development with ecosystem services provision.
    Matched MeSH terms: Water
  12. New efficient chitosan derivative for Cu(II) ions removal: Characterization and adsorption performance
    Sutirman ZA, Rahim EA, Sanagi MM, Abd Karim KJ, Wan Ibrahim WA
    Int J Biol Macromol, 2020 Jun 15;153:513-522.
    PMID: 32142849 DOI: 10.1016/j.ijbiomac.2020.03.015
    A new crosslinked chitosan grafted with methyl methacrylate (M-CTS) adsorbent was synthesized via free radical polymerization for effective removal of Cu(II) ions from aqueous solution. Crosslinked chitosan (1 g) was grafted with 29.96 × 10-1 M methyl methacrylate in the presence of 2.63 × 10-1 M ammonium persulfate as initiator at 60 °C for 2 h to give grafting and yield percentages of 201% and 67%, respectively. Batch adsorption experiment was performed as a function of solution pH, initial metal ion concentration and contact time. The isotherm data were adequately described by Langmuir model, while kinetic study revealed that the pseudo-second order rate model best fitted for the experimental data. The maximum adsorption capacity for M-CTS at pH 4 was 192.31 mg g-1. Furthermore, the reusability of over six adsorption-desorption cycles suggested that M-CTS is a durable adsorbent and good candidate for metal ions treatment.
    Matched MeSH terms: Water
  13. Fulltext Determination of the Major Component of Water Fraction of Katuk (Sauropus androgynous (L.) Merr.) Leaves by Liquid Chromatography-Mass Spectrometry
    Mustarichie R, Salsabila T, Iskandar Y
    J Pharm Bioallied Sci, 2019 Dec;11(Suppl 4):S611-S618.
    PMID: 32148372 DOI: 10.4103/jpbs.JPBS_205_19
    Background: The katuk leaf (Sauropus androgynous (L.) Merr.) is one of the plants that are used to overcome baldness by the people of Kampung Mak Kemas, Malaysia. It is suspected that secondary metabolites contained in katuk leaves play a key role in stimulating hair growth.

    Aims and Objectives: The aim of this study was to identify the optimum method to obtain one of the chemical compounds in the water fraction and to identify the hypothesized chemical isolates in the water fraction katuk leave's ethanol extract.

    Materials and Methods: The methods used in this study included the collection and determination of the katuk plant, the processing of the katuk, phytochemical filtrating, extracting with ethanol 96%, and fractionation using the liquid-liquid extraction method with n-hexane, ethyl acetate, and water solvents The water fraction of katuk leaves was analyzed by its components by thin-layer chromatography using the stationary phase of silica gel 60 F254, developer of n-butanol:acetic acid:water (4:1:5), and detection under ultraviolet (UV) light at a wavelength of 366 and 254nm, as well as with vanillin-sulfuric acid reagent. To isolate the compounds from water fraction of katuk leaves, it was then eluted with a vacuum column chromatography by eluent with a level polarity that would get 11 subfractions. Each subfraction was checked by two-dimensional thin-layer chromatography to see subfraction purity characterized by the appearance of a spot on the chromatogram plate. The isolate was analyzed using spot test, ultraviolet-visible spectrophotometer, infrared spectrophotometer, and liquid chromatography-mass spectrometry.

    Results: The isolate was an alkaloid compound with a molecular mass of 406.3131 m/z with the molecular formula C21H39N6O2 as S, S-5, 5'-amino-4,4'-dihexyl-propyldihydropyrazol-3, 3-one.

    Conclusion: One of the chemical compounds contained in the water fraction of the ethanol extract of the katuk leaf was an alkaloid group.

    Matched MeSH terms: Water
  14. Total vulnerability of the littoral zone to climate change-driven natural hazards in north Brittany, France
    Mathew MJ, Sautter B, Ariffin EH, Menier D, Ramkumar M, Siddiqui NA, et al.
    Sci Total Environ, 2020 Mar 01;706:135963.
    PMID: 31862602 DOI: 10.1016/j.scitotenv.2019.135963
    Current worldwide projections of sea-level rise show a staggering increase in water level of up to 2 m by 2100 owing to global warming exacerbated by anthropogenically induced climate change. While amplified rates of sea-level rise is an immense hazard to coastal communities, storm surges are expected to increase in intensity and frequency making it an equally significant threat to coastal populations. In France, these hazards are not uncommon with records of extreme tempests every thousand years in the Holocene. Despite these recurring devastating events, in the Bay of Saint-Brieuc, Brittany, legislated laws for coastal management do not entirely focus on protecting littoral zones from such calamities. 130,739 people are concentrated in 21 municipalities with major cities located at close proximity to the shoreline with numerous socio-economic activities, which increases the vulnerability of the coastal population and infrastructures; thus, affirming the indispensable need of a thorough vulnerability assessment. Here, we conduct a mechanistic appraisal of the vulnerability of the bay considering thirteen parameters within three governing sub-systems that demonstrate the multidimensional dynamics in these municipalities. In the occasion of an extreme climatic event, our results of total vulnerability show risks in the sub-systems highlighting erosional processes due to augmented hydrodynamics, socio-economic and administrative vulnerabilities associated with anthropogenic development. Eight municipalities of the bay portray moderate to very high vulnerability and the remaining exhibits a lower risk; however, not devoid of high vulnerabilities for certain sub-systems. We posit that a more accurate fit for predicting the total vulnerability of the region can be achieved by exclusively integrating physical-natural and administrative sub-system vulnerabilities. We propose generic but requisite recommendations for Integrated Coastal Zone Management such as surveillance of urban development along the coast, implementation of coastal defense systems and appropriate industrial corridors to attenuate and dispose hazardous refuse.
    Matched MeSH terms: Water
  15. Fulltext Improving Performance of Electrospun Nylon 6,6 Nanofiber Membrane for Produced Water Filtration via Solvent Vapor Treatment
    Abd Halim NS, Wirzal MDH, Bilad MR, Md Nordin NAH, Adi Putra Z, Sambudi NS, et al.
    Polymers (Basel), 2019 Dec 17;11(12).
    PMID: 31861059 DOI: 10.3390/polym11122117
    Electrospun nanofiber membrane (NFM) has a high potential to be applied as a filter for produced water treatment due to its highly porous structure and great permeability. However, it faces fouling issues and has low mechanical properties, which reduces the performance and lifespan of the membrane. NFM has a low integrity and the fine mat easily detaches from the sheet. In this study, nylon 6,6 was selected as the polymer since it offers great hydrophilicity. In order to increase mechanical strength and separation performance of NFM, solvent vapor treatment was implemented where the vapor induces the fusion of fibers. The fabricated nylon 6,6 NFMs were treated with different exposure times of formic acid vapor. Results show that solvent vapor treatment helps to induce the fusion of overlapping fibers. The optimum exposure time for solvent vapor is 5 h to offer full retention of dispersed oil (100% of oil rejection), has 62% higher in tensile strength (1950 MPa) compared to untreated nylon 6,6 NFM (738 MPa), and has the final permeability closest to the untreated nylon 6,6 NFM (733 L/m2.h.bar). It also took more time to get fouled (220 min) compared to untreated NFM (160 min).
    Matched MeSH terms: Water Purification
  16. Fulltext Influence of Glass Silica Waste Nano Powder on the Mechanical and Microstructure Properties of Alkali-Activated Mortars
    Samadi M, Shah KW, Huseien GF, Lim NHAS
    Nanomaterials (Basel), 2020 Feb 14;10(2).
    PMID: 32075038 DOI: 10.3390/nano10020324
    The recycling of millions of tons of glass bottle waste produced each year is far from optimal. In the present work, ground blast furnace slag (GBFS) was substituted in fly ash-based alkali-activated mortars (AAMs) for the purpose of preparing glass bottle waste nano-powder (BGWNP). The AAMs mixed with BGWNP were subsequently subjected to assessment in terms of their energy consumption, economic viability, and mechanical and chemical qualities. Besides affording AAMs better mechanical qualities and making them more durable, waste recycling was also observed to diminish the emissions of carbon dioxide. A more than 6% decrease in carbon dioxide emissions, an over 16% increase in compressive strength, better durability and lower water absorption were demonstrated by AAM consisting of 5% BGWNP as a GBFS substitute. By contrast, lower strength was exhibited by AAM comprising 10% BGWNP. The conclusion reached was that the AAMs produced with BGWNP attenuated the effects of global warming and thus were environmentally advantageous. This could mean that glass waste, inadequate for reuse in glass manufacturing, could be given a second life rather than being disposed of in landfills, which is significant as concrete remains the most commonplace synthetic material throughout the world.
    Matched MeSH terms: Water
  17. In vitro digestion and domestic cooking improved the total antioxidant activity and carbohydrate-digestive enzymes inhibitory potential of selected edible mushrooms
    Ng ZX, Rosman NF
    J Food Sci Technol, 2019 Feb;56(2):865-877.
    PMID: 30906044 DOI: 10.1007/s13197-018-3547-6
    This study aimed to investigate the effect of in vitro digestion on the antioxidant activity and carbohydrate-digestive enzymes inhibitory potential of five edible mushrooms after subjected to four domestic cooking; namely, boiling, microwaving, steaming and pressure-cooking. The water extracts of raw (uncooked), cooked and in vitro digested mushrooms were compared for their water-soluble phenolic content (WPC), total flavonoid content (TFC), ferric reducing antioxidant power (FRAP), radical scavenging activity (TEAC and DPPH), anti-α-amylase and anti-α-glucosidase activities. Among the raw samples, Lentinula edodes possessed the highest antioxidant activities (FRAP, TEAC, DPPH) and WPC while Pleurotus sajor-caju displayed the highest TFC, anti-α-amylase and anti-α-glucosidase activities. The antioxidant and carbohydrate-digestive enzyme inhibitory activities significantly varied according to mushroom species and cooking methods applied. Short duration of microwaving (Agaricus bisporus and Flammulina velutipes), boiling (Auricularia polytricha) and pressure cooking (L. edodes and P. sajor-caju) yielded the best antioxidant and carbohydrate-digestive enzymes inhibition values in the mushroom extracts. TFC was positively correlated with the antioxidant activities and anti-α-glucosidase activity in the mushroom extracts. In vitro digestion significantly improved the total antioxidant and anti-α-glucosidase activities but decreased the anti-α-amylase activity in the cooked mushroom extracts. Principle component analysis showed that in vitro digestion and the cooking process accounted for respective 48.9% and 19.7% of variation in the observed activities. Domestic cooking and in vitro digestion could potentiate the total antioxidant and carbohydrate-digestive enzymes inhibitory activities in the selected water extract of edible mushrooms.
    Matched MeSH terms: Water
  18. Fulltext Geometric morphometric analysis in female freshwater crabs of Sarawak (Borneo) permits addressing taxonomy-related problems
    Grinang J, Das I, Ng PKL
    PeerJ, 2019;7:e6205.
    PMID: 30783559 DOI: 10.7717/peerj.6205
    The taxonomy of freshwater crabs requires a paradigm change in methodological approaches, particularly in investigations that use morphological techniques. The traditional morphometric approach (two-dimensional measurements) tends to be inappropriate for the identification of freshwater crabs due to their variable external morphology and lack of gonopods (conventionally used for the identification of male crabs) in females. In this study, we explore the potential use of the geometric morphometric technique for identification of female freshwater crabs, and identify taxonomic key characteristics of species. The shape of the carapace could be a good characteristic for the identification of female crabs, especially when the geometric morphometric technique is used. It was observed that the shape of the carapace has an advantage over the shape of the pleon and chela because its relatively flat orientation allows more consistent and easier data preparation for geometric morphometric analysis. The geometric morphometric technique is inexpensive, relatively less time consuming to employ, and accurate. This technique is convenient when dissection to examine the gonopods is not possible, which can damage the specimen in the case of endangered or rare species. Since the technique was used herein for only two species, more compelling and extensive evidence is needed before the reliability of the method can be proven.
    Matched MeSH terms: Fresh Water
  19. Fulltext Real Time Microwave Biochemical Sensor Based on Circular SIW Approach for Aqueous Dielectric Detection
    Mohd Bahar AA, Zakaria Z, Md Arshad MK, Isa AAM, Dasril Y, Alahnomi RA
    Sci Rep, 2019 04 02;9(1):5467.
    PMID: 30940843 DOI: 10.1038/s41598-019-41702-3
    In this study, a critical evaluation of analyte dielectric properties in a microvolume was undertaken, using a microwave biochemical sensor based on a circular substrate integrated waveguide (CSIW) topology. These dielectric properties were numerically investigated based on the resonant perturbation method, as this method provides the best sensing performance as a real-time biochemical detector. To validate these findings, shifts of the resonant frequency in the presence of aqueous solvents were compared with an ideal permittivity. The sensor prototype required a 2.5 µL volume of the liquid sample each time, which still offered an overall accuracy of better than 99.06%, with an average error measurement of ±0.44%, compared with the commercial and ideal permittivity values. The unloaded Qu factor of the circular substrate-integrated waveguide (CSIW) sensor achieved more than 400 to ensure a precise measurement. At 4.4 GHz, a good agreement was observed between simulated and measured results within a broad frequency range, from 1 to 6 GHz. The proposed sensor, therefore, offers high sensitivity detection, a simple structural design, a fast-sensing response, and cost-effectiveness. The proposed sensor in this study will facilitate real improvements in any material characterization applications such as pharmaceutical, bio-sensing, and food processing applications.
    Matched MeSH terms: Water
  20. Impact of molecular structure, headgroup and alkyl chain geometry, on the adsorption of the anionic ester sulfonate surfactants at the air-solution interface, in the presence and absence of electrolyte
    Wang Z, Li P, Ma K, Chen Y, Campana M, Penfold J, et al.
    J Colloid Interface Sci, 2019 May 15;544:293-302.
    PMID: 30861434 DOI: 10.1016/j.jcis.2019.03.011
    The transition from monolayer to multilayer adsorption at the air-water interface in the presence of multivalent counterions has been demonstrated for a limited range of anionic surfactants which exhibit increased tolerance to precipitation in the presence of multivalent counterions. Understanding the role of molecular structure in determining the transition to surface ordering is an important aspect of the phenomenon. The focus of the paper is on the alkyl ester sulfonate, AES, surfactants; a promising group of anionic surfactants, with the potential for improved performance and biocompatibility. Neutron reflectivity measurements were made in aqueous solution and in the presence of NaCl, CaCl2, MgCl2 and AlCl3, for a range of alkyl ester sulfonate surfactants, in which the headgroup and alkyl chain geometries were manipulated. In the regions of monolayer adsorption changing the AES headgroup and alkyl chain geometries results in an increased saturation adsorption and in a more gradual decrease in the adsorption at low concentrations, consistent with a greater adsorption efficiency. Changing the AES headgroup and alkyl chain geometries also results in changes in the transition from monolayer adsorption to more ordered surface structures with the addition of AlCl3 and mixed multivalent electrolytes. A more limited surface layering is observed for the ethyl ester sulfonate, EES, with a C14 alkyl chain. Replacing the C14 alkyl chain with a C18 isostearic chain results in only monolayer adsorption. The results demonstrate the role and importance of the surfactant molecular structure in determining the nature of the surface adsorption in the presence of different electrolytes, and in the tendency to form extended surface multilayer structures.
    Matched MeSH terms: Water
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