Displaying publications 601 - 620 of 4697 in total

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  1. Description of a Giardia varani-like flagellate from a water monitor, Varanus salvator, from Malaysia
    Upton SJ, Zien CA
    J Parasitol, 1997 Oct;83(5):970-1.
    PMID: 9379313
    A Giardia varani Lavier, 1923-like flagellate was found in the feces of a captive water monitor, Varanus salvator, originally caught wild from an unknown location in Malaysia. The parasite is similar in size and shape to Giardia lamblia, except that median bodies are rare and cysts are binucleate. A description of both the trophozoite and cyst stage of this flagellate is provided.
    Matched MeSH terms: Giardia/isolation & purification
  2. Purification of lysozyme from chicken egg white by high-density cation exchange adsorbents in stirred fluidized bed adsorption system
    Show PL, Ooi CW, Song CP, Chai WS, Lin GT, Liu BL, et al.
    Food Chem, 2021 May 01;343:128543.
    PMID: 33187742 DOI: 10.1016/j.foodchem.2020.128543
    Lysozyme from crude chicken egg white (CEW) feedstock was successfully purified using a stirred fluidized bed adsorption system ion exchange chromatography where STREAMLINE SP and SP-XL high density adsorbents were selected as the adsorption carrier. The thermodynamic and kinetic studies were carried out to understand the characteristics of lysozyme adsorption by adsorbents under various conditions, including adsorption pH, temperature, lysozyme concentration and salt concentrations. Results showed that SP and SP-XL adsorbents achieved optimum lysozyme adsorption at pH 9 with capacity of ~139.77 and ~251.26 mg/mL, respectively. The optimal conditions obtained from batch studies were directly employed to operate in SFBA process. For SP-XL adsorbent, the recovery yield and purification factor of lysozyme were 93.78% and ~40 folds, respectively. For SP adsorbent, lysozyme can be eluted ~100% with purification factor of ~26 folds. These two adsorbents are highly suitable for use in direct recovery of lysozyme from crude CEW.
    Matched MeSH terms: Muramidase/isolation & purification*
  3. Comparison of Campylobacter contamination levels on chicken carcasses between modern and traditional types of slaughtering facilities in Malaysia
    Rejab SB, Zessin KH, Fries R, Patchanee P
    J Vet Med Sci, 2012 Jan;74(1):121-4.
    PMID: 21891977
    A total of 360 samples including fresh fecal droppings, neck skins, and swab samples was collected from 24 broiler flocks and processed by 12 modern processing plants in 6 states in Malaysia. Ninety samples from 10 traditional wet markets located in the same states as modern processing plants were also collected. Microbiological isolation for Campylobacter was performed following ISO 10272-1:2006 (E). The overall rate of contamination for Campylobacter in modern processing plants and in traditional wet markets was 61.1% (220/360) and 85.6% (77/90), respectively. Campylobacter jejuni was detected as the majority with approximately 70% for both facilities. In the modern processing plants, the contamination rate for Campylobacter gradually declined from 80.6% before the inside-outside washing to 62.5% after inside-outside washing and to 38.9% after the post chilling step. The contamination rate for Campylobacter from processed chicken neck skin in traditional wet markets (93.3%) was significantly (P<0.01) higher than in modern processing plants (38.9%).
    Matched MeSH terms: Campylobacter/isolation & purification*
  4. High methoxyl pectin extracts from Hylocereus polyrhizus's peels: Extraction kinetics and thermodynamic studies
    Zaid RM, Mishra P, Tabassum S, Wahid ZA, Sakinah AMM
    Int J Biol Macromol, 2019 Dec 01;141:1147-1157.
    PMID: 31494156 DOI: 10.1016/j.ijbiomac.2019.09.017
    The effect of physicochemical treatment on pectin yield, degree of esterification, along with the kinetics and thermodynamics characteristics was investigated in the present study. Several extraction parameters were observed to have impacted the yield and degree of esterification significantly, and the best extraction condition was as follows: agitation rate of 250 rpm, temperature of 70 °C, extraction time of 120 min, pH 2, and liquid to solid ratio of 10 v/w which has resulted in 28.20% of pectin yield, with DE (degree of esterification) of 57.00%. A theoretical model which describes the extractability, dissolution and degradation rate of pectin to predict the maximal yield at the maximal time was established to study the extraction kinetics of pectin from HPP. The kinetic analysis from Panchev's model shows the extraction rate was found highest at LSR 10 with ymax 30.85%. The calculated activation energy for pectin dissolution and degradation was found to be 4.532 kJ/mol and 28.054 kJ/mol, respectively. The thermodynamic study has suggested that the process was endothermic, spontaneous and reversible. These results suggest that the physical and chemical treatment applied could be an efficient technique for the extraction of pectin from Hylocereus polyrhizus peels.
    Matched MeSH terms: Pectins/isolation & purification*
  5. Detection of Babesia spp. in Dogs and Their Ticks From Peninsular Malaysia: Emphasis on Babesia gibsoni and Babesia vogeli Infections in Rhipicephalus sanguineus sensu lato (Acari: Ixodidae)
    Prakash BK, Low VL, Vinnie-Siow WY, Tan TK, Lim YA, Morvarid AR, et al.
    J Med Entomol, 2018 Aug 29;55(5):1337-1340.
    PMID: 29762747 DOI: 10.1093/jme/tjy072
    Canine babesiosis is an emerging tick-borne disease with a worldwide distribution, including Malaysia. While the prevalence of Babesia has been documented from dogs in Malaysia, occurrence of Babesia has been relatively little studied in their tick vectors. Accordingly, a total of 240 dogs and 140 Rhipicephalus sanguineus sensu lato (s.l.) (Acari: Ixodidae) ticks from Malaysia were molecularly screened for the presence of Babesia protozoa in the present study. Babesia gibsoni was only detected in ticks (1.4%), whereas Babesia vogeli was detected in both ticks (1.4%) and dogs (2.1%). This study highlights the detection of B. gibsoni and B. vogeli for the first time, in both adult and nymphal stages of R. sanguineus s.l. in Malaysia, suggesting the potential role of this tick species in transmitting canine babesiosis.
    Matched MeSH terms: Babesia/isolation & purification*
  6. Structure-informed separation of bioactive peptides
    Acquah C, Chan YW, Pan S, Agyei D, Udenigwe CC
    J Food Biochem, 2019 01;43(1):e12765.
    PMID: 31353493 DOI: 10.1111/jfbc.12765
    The application of proteomic and peptidomic technologies for food-derived bioactive peptides is an emerging field in food sciences. These technologies include the use of separation tools coupled to a high-resolution spectrometric and bioinformatic tools for prediction, identification, sequencing, and characterization of peptides. To a large extent, one-dimensional separation technologies have been extensively used as a continuous tool under different optimized conditions for the identification and analysis of food peptides. However, most one-dimensional separation technologies are fraught with significant bottlenecks such as insufficient sensitivity and specificity limits for complex samples. To address this limitation, separation systems based on orthogonal, multidimensional principles, which allow for the coupling of more than one analytical separation tool with different operational principles, provide a higher separation power than one-dimensional separation tools. This review describes the structure-informed separation and purification of protein hydrolyzates to obtain peptides with desirable bioactivities. PRACTICAL APPLICATIONS: Application of bioactive peptides in the formulation of functional foods, nutraceuticals, and therapeutic agents have increasingly gained scholarly and industrial attention. The bioactive peptides exist originally in protein sources and are only active after hydrolysis of the parent protein. Currently, several tools can be configured in one-dimensional or multidimensional systems for the separation and purification of protein hydrolyzates. The separations are informed by the structural properties such as the molecular weight, charge, hydrophobicity or hydrophilicity, and the solubility of peptides. This review provides a concise discussion on the commonly used analytical tools, their configurations, advantages and challenges in peptide separation. Emphasis is placed on how the structural properties of peptides assist in the separation and purification processes and the concomitant effect of the separation on peptide bioactivity.
    Matched MeSH terms: Peptides/isolation & purification*
  7. Fulltext Subcritical Water Extraction of Chlorella pyrenoidosa: Optimization through Response Surface Methodology
    Thiruvenkadam S, Izhar S, Hiroyuki Y, Harun R
    Biomed Res Int, 2018;2018:1931634.
    PMID: 30533428 DOI: 10.1155/2018/1931634
    Subcritical water extraction (SCW) was used to extract oil from Chlorella pyrenoidosa. The operational factors such as reaction temperature, reaction time, and biomass loading influence the oil yield during the extraction process. In this study, response surface methodology was employed to identify the desired extraction conditions for maximum oil yield. Experiments were carried out in batch reactors as per central composite design with three independent factors including reaction temperature (170, 220, 270, 320, and 370°C), reaction time (1, 5, 10, 15, and 20 min), and biomass loading (1, 3, 5, 10, and 15%). A maximum oil yield of 12.89 wt.% was obtained at 320°C and 15 min, with 3% biomass loading. Sequential model tests showed the good fit of experimental data to the second-order quadratic model. This study opens the great potential of SCW to extract algal oil for use in algal biofuel production.
    Matched MeSH terms: Chlorella/isolation & purification*
  8. Fulltext Treatment of Wastewater Using Seaweed: A Review
    Arumugam N, Chelliapan S, Kamyab H, Thirugnana S, Othman N, Nasri NS
    Int J Environ Res Public Health, 2018 12 13;15(12).
    PMID: 30551682 DOI: 10.3390/ijerph15122851
    Inadequately treated or untreated wastewater greatly contribute to the release of unwanted toxic contaminants into water bodies. Some of these contaminants are persistent and bioaccumulative, becoming a great concern as they are released into the environment. Despite the abundance of wastewater treatment technologies, the adsorption method overall has proven to be an excellent way to treat wastewater from multiple industry sources. Because of its significant benefits, i.e., easy availability, handling, and higher efficiency with a low cost relative to other treatments, adsorption is opted as the best method to be used. However, biosorption using naturally found seaweeds has been proven to have promising results in removing pollutants, such as dyes from textile, paper, and the printing industry, nitrogen, and phosphorous and phenolic compounds, as well as heavy metals from various sources. Due to its ecofriendly nature together with the availability and inexpensiveness of raw materials, biosorption via seaweed has become an alternative to the existing technologies in removing these pollutants from wastewater effectively. In this article, the use of low-cost adsorbent (seaweed) for the removal of pollutants from wastewater has been reviewed. An extensive table summarises the applicability of seaweed in treating wastewater. Literature reported that the majority of research used simulated wastewater and minor attention has been given to biosorption using seaweed in the treatment of real wastewater.
    Matched MeSH terms: Water Pollutants, Chemical/isolation & purification*
  9. Fulltext Measles infection causing Bacillus Calmette-Guérin reactivation: a case report
    Muthuvelu S, Lim KS, Huang LY, Chin ST, Mohan A
    BMC Pediatr, 2019 07 24;19(1):251.
    PMID: 31340782 DOI: 10.1186/s12887-019-1635-z
    BACKGROUND: Reactivation of the Bacillus Calmette-Guérin (BCG), manifesting as erythema, induration, ulceration or crust formation at a previous BCG inoculation site, is a common and highly specific feature of Kawasaki disease (KD). We report the unusual finding of BCG reactivation in an infant with laboratory-confirmed measles.

    CASE PRESENTATION: A previously healthy 7-month old infant presented initially with fever, cough and coryza, and subsequently developed Koplik's spots followed by a typical morbilliform skin rash. There was significant contact history with a household relative who had recently been diagnosed with measles. On examination, a 2.5 cm area of erythema and induration was seen at the previous BCG inoculation site, in addition to the widespread maculopapular rash. No other clinical features of KD were present. Measles virus was isolated from the throat swab and measles antibodies (IgM) were present in the serum. The patient recovered completely with oral vitamin A and supportive therapy, and had normal echocardiography examination on follow up.

    CONCLUSIONS: This case report highlights the rare finding of BCG reactivation in a child with confirmed measles infection, and suggests that this clinical manifestation may occasionally occur in children with infections or conditions other than KD.

    Matched MeSH terms: Measles virus/isolation & purification*
  10. Fulltext Ophthalmia Neonatorum
    Tan AK
    N Engl J Med, 2019 Jan 10;380(2):e2.
    PMID: 30625059 DOI: 10.1056/NEJMicm1808613
    Matched MeSH terms: Chlamydia trachomatis/isolation & purification*
  11. Fulltext Identification of a Newly Isolated Getah Virus in the China-Laos Border, China
    Li YY, Fu SH, Guo XF, Lei WW, Li XL, Song JD, et al.
    Biomed Environ Sci, 2017 Mar;30(3):210-214.
    PMID: 28427491 DOI: 10.3967/bes2017.028
    In this study, we isolated a virus strain (YN12031) from specimens of Armigeres subalbatus collected in the China-Laos border. BHK-21 cells infected with YN12031 exhibited an evident cytopathic effect (CPE) 32 h post-infection. The virus particles were spherical, 70 nm in diameter, and enveloped; they also featured surface fibers. Molecular genetic analysis revealed that YN12031 was closely related to alpha viruses such as Chikungunya virus and Sindbis virus, and located in the same clade as MM2021, the prototype of Getahvirus (GETV) isolated in Malaysia in 1955. Phylogenetic analysis of the E2 and capsid genes further revealed that YN12031 was located in the same clade as the Russian isolate LEIV/16275/Mag. Analysis of the homology of nucleotides and amino acids in the coding area and E2 gene demonstrated that the YN12031 isolated from the China-Laos border (tropical region) was related closest to the LEIV/16275/Mag isolate obtained in Russia (North frigid zone area) among other isolates studied. These results suggest that GETV can adapt to different geographical environments to propagate and evolve. Thus, strengthening the detection and monitoring of GETV and its related diseases is very crucial.
    Matched MeSH terms: Alphavirus/isolation & purification*
  12. Fulltext Detection of Laem-Singh virus in cultured Penaeus monodon shrimp from several sites in the Indo-Pacific region
    Sittidilokratna N, Dangtip S, Sritunyalucksana K, Babu R, Pradeep B, Mohan CV, et al.
    Dis Aquat Organ, 2009 Apr 27;84(3):195-200.
    PMID: 19565696 DOI: 10.3354/dao02059
    Laem-Singh virus (LSNV) is a positive-sense single-stranded RNA (ssRNA) virus that was recently identified in Penaeus monodon shrimp in Thailand displaying signs of slow growth syndrome. A total of 326 shrimp collected between 1998 and 2007 from countries in the Indo-Pacific region were tested by RT-PCR for evidence of LSNV infection. The samples comprised batches of whole postlarvae, and lymphoid organ, gill, muscle or pleopod tissue of juvenile, subadult and adult shrimp. LSNV was not detected in 96 P. monodon, P. japonicus or P. merguiensis from Australia or 16 P. monodon from Fiji, Philippines, Sri Lanka and Mozambique. There was no evidence of LSNV infection in 73 healthy juvenile P. vannamei collected during 2006 from ponds at 9 locations in Thailand. However, LNSV was detected in each of 6 healthy P. monodon tested from Malaysia and Indonesia, 2 of 6 healthy P. monodon tested from Vietnam and 39 of 40 P. monodon collected from slow-growth ponds in Thailand. A survey of 81 P. monodon collected in 2007 from Andhra Pradesh, India, indicated 56.8% prevalence of LSNV infection but no clear association with disease or slow growth. Phylogenetic analysis of PCR amplicons obtained from samples from India, Vietnam, Malaysia and Thailand indicated that nucleotide sequence variation was very low (>98% identity) and there was no clustering of viruses according to site of isolation or the health status of the shrimp. The data suggests that LSNV exists as a single genetic lineage and occurs commonly in healthy P. monodon in parts of Asia.
    Matched MeSH terms: RNA Viruses/isolation & purification*
  13. Black piedra in west Malaysia
    Adam BA, Soo-Hoo TS, Chong KC
    Australas J Dermatol, 1977 Apr;18(1):45-7.
    PMID: 883925
    Matched MeSH terms: Ascomycota/isolation & purification
  14. A novel insecticidal serotype of Clostridium bifermentans
    Seleena P, Lee HL, Lecadet MM
    J Am Mosq Control Assoc, 1997 Dec;13(4):395-7.
    PMID: 9474569
    A novel Clostridium bifermentans strain toxic to mosquito larvae on ingestion was isolated from a soil sample collected from secondary forest floor. This strain was designated as serovar paraiba (C. b. paraiba) according to its specific H antigen. Clostridium bifermentans paraiba is most toxic to Anopheles maculatus Theobald larvae (LC50 = 0.038 mg/liter), whereas toxicity to Aedes aegypti (Linn.) (LC50 = 0.74 mg/liter) and Culex quinquefasciatus Say (LC50 = 0.11 mg/liter) larvae was 20 and 3 times lower, respectively. The toxicity to An. maculatus larvae is as high as that of Bacillus thuringiensis serovar israelensis. C. b. paraiba was also found to exhibit significant per os insecticidal activity toward adult Musca domestica (Linn.).
    Matched MeSH terms: Clostridium/isolation & purification*
  15. Shigellosis in Kobe City, Japan, after school excursion to Malaysia and Singapore
    Kimura T, Inoue A, Kawakami Y, Shirai C
    Jpn J Infect Dis, 2006 Aug;59(4):274.
    PMID: 16936352
    Matched MeSH terms: Shigella sonnei/isolation & purification*
  16. Distinctive phyllosphere bacterial communities in tropical trees
    Kim M, Singh D, Lai-Hoe A, Go R, Abdul Rahim R, Ainuddin AN, et al.
    Microb Ecol, 2012 Apr;63(3):674-81.
    PMID: 21990015 DOI: 10.1007/s00248-011-9953-1
    Recent work has suggested that in temperate and subtropical trees, leaf surface bacterial communities are distinctive to each individual tree species and dominated by Alpha- and Gammaproteobacteria. In order to understand how general this pattern is, we studied the phyllosphere bacterial community on leaves of six species of tropical trees at a rainforest arboretum in Malaysia. This represents the first detailed study of 'true' tropical lowland tree phyllosphere communities. Leaf surface DNA was extracted and pyrosequenced targeting the V1-V3 region of 16S rRNA gene. As was previously found in temperate and subtropical trees, each tree species had a distinctive bacterial community on its leaves, clustering separately from other tree species in an ordination analysis. Bacterial communities in the phyllosphere were unique to plant leaves in that very few operational taxonomic units (0.5%) co-occurred in the surrounding soil environment. A novel and distinctive aspect of tropical phyllosphere communities is that Acidobacteria were one of the most abundant phyla across all samples (on average, 17%), a pattern not previously recognized. Sequences belonging to Acidobacteria were classified into subgroups 1-6 among known 24 subdivisions, and subgroup 1 (84%) was the most abundant group, followed by subgroup 3 (15%). The high abundance of Acidobacteria on leaves of tropical trees indicates that there is a strong relationship between host plants and Acidobacteria in tropical rain forest, which needs to be investigated further. The similarity of phyllosphere bacterial communities amongst the tree species sampled shows a significant tendency to follow host plant phylogeny, with more similar communities on more closely related hosts.
    Matched MeSH terms: Bacteria/isolation & purification*
  17. Impact of Land-use Change on Vertical Soil Bacterial Communities in Sabah
    Tin HS, Palaniveloo K, Anilik J, Vickneswaran M, Tashiro Y, Vairappan CS, et al.
    Microb Ecol, 2018 Feb;75(2):459-467.
    PMID: 28779295 DOI: 10.1007/s00248-017-1043-6
    Decline in forest productivity due to forest conversion is defining the Bornean landscape. Responses of bacterial communities due to land-use changes are vital and could define our understanding of ecosystem functions. This study reports the changes in bacterial community structure in organic soil (0-5 cm; O-Horizon) and organic-mineral soil (5-15 cm; A-Horizon) across Maliau Basin Conservation Area old growth forest (MBOG), Fragment E logged forest (FELF) located in Kalabakan Forest Reserve to Benta Wawasan oil palm plantation (BWOP) using two-step PCR amplicon analysis of bacteria DNA on Illumina Miseq next generation sequencing. A total of 30 soil samples yielded 893,752-OTU reads at ≥97% similarity from 5,446,512 good quality sequences. Soil from BWOP plantation showed highest unshared OTUs for organic (49.2%) and organic-mineral (50.9%) soil. MBOG soil showed a drop in unshared OTUs between organic (48.6%) and organic-mineral (33.9%). At phylum level, Proteobacteria dominated MBOG but shifted to Actinobacteria in logged and plantation soil. Present findings also indicated that only FELF exhibited change in bacterial communities along the soil depth, moving from the organic to the organic-mineral layer. Both layers of BWOP plantation soils deviated from other forests' soil in β-diversity analysis. To our knowledge, this is the first report on transitions of bacterial community structures with different soil horizons in the tropical rainforest including Borneo, Sabah. Borneo tropical soils form a large reservoir for soil bacteria and future exploration is needed for fully understanding the diversity structure and their bacterial functional properties.
    Matched MeSH terms: Bacteria/isolation & purification*
  18. Fulltext Contaminating viral sequences in high-throughput sequencing viromics: a linkage study of 700 sequencing libraries
    Asplund M, Kjartansdóttir KR, Mollerup S, Vinner L, Fridholm H, Herrera JAR, et al.
    Clin Microbiol Infect, 2019 Oct;25(10):1277-1285.
    PMID: 31059795 DOI: 10.1016/j.cmi.2019.04.028
    OBJECTIVES: Sample preparation for high-throughput sequencing (HTS) includes treatment with various laboratory components, potentially carrying viral nucleic acids, the extent of which has not been thoroughly investigated. Our aim was to systematically examine a diverse repertoire of laboratory components used to prepare samples for HTS in order to identify contaminating viral sequences.

    METHODS: A total of 322 samples of mainly human origin were analysed using eight protocols, applying a wide variety of laboratory components. Several samples (60% of human specimens) were processed using different protocols. In total, 712 sequencing libraries were investigated for viral sequence contamination.

    RESULTS: Among sequences showing similarity to viruses, 493 were significantly associated with the use of laboratory components. Each of these viral sequences had sporadic appearance, only being identified in a subset of the samples treated with the linked laboratory component, and some were not identified in the non-template control samples. Remarkably, more than 65% of all viral sequences identified were within viral clusters linked to the use of laboratory components.

    CONCLUSIONS: We show that high prevalence of contaminating viral sequences can be expected in HTS-based virome data and provide an extensive list of novel contaminating viral sequences that can be used for evaluation of viral findings in future virome and metagenome studies. Moreover, we show that detection can be problematic due to stochastic appearance and limited non-template controls. Although the exact origin of these viral sequences requires further research, our results support laboratory-component-linked viral sequence contamination of both biological and synthetic origin.

    Matched MeSH terms: Viruses/isolation & purification*
  19. Fulltext Profiling of Potential Antibacterial Compounds of Lactic Acid Bacteria against Extremely Drug Resistant (XDR) Acinetobacter baumannii
    Yap PC, Ayuhan N, Woon JJ, Teh CSJ, Lee VS, Azman AS, et al.
    Molecules, 2021 Mar 19;26(6).
    PMID: 33808805 DOI: 10.3390/molecules26061727
    A total of 20 of isolates of lactic acid bacteria (LAB) were selected and screened for antagonistic activity against clinical strains of 30 clinical isolates of extremely drug-resistant (XDR) Acinetobacter baumannii using the well diffusion assay method. Results showed that 50% of the highly LAB strains possessed inhibitory activity against (up to 66%) of the XDR A. baumannii strains tested. The supernatant of the twenty LAB strains was subjected to gas chromatography mass spectrometry (GCMS) revealed that the common compound found in the active isolates against XDR A. baumannii was 3-Isobutyl-2,3,6,7,8,8a-hexahydropyrrolo[1,2-a]pyrazine-1,4-dione, a known potential diketopiperazine group. The molecular docking study against potential antibacterial targets with selected ligands was performed to predict the binding mode of interactions, which is responsible for antibacterial activity. The docking analysis of the potent compounds supported the potential antibacterial activity exhibiting high inhibition constant and binding affinity in silico.
    Matched MeSH terms: Lactobacillales/isolation & purification
  20. Fulltext Experimental evaluation of oil recovery mechanism using a variety of surface-modified silica nanoparticles: Role of in-situ surface-modification in oil-wet system
    Adil M, Mohd Zaid H, Raza F, Agam MA
    PLoS One, 2020;15(7):e0236837.
    PMID: 32730369 DOI: 10.1371/journal.pone.0236837
    Recent developments propose renewed use of surface-modified nanoparticles (NPs) for enhanced oil recovery (EOR) due to improved stability and reduced porous media retention. The enhanced surface properties render the nanoparticles more suitable compared to bare nanoparticles, for increasing the displacement efficiency of waterflooding. However, the EOR mechanisms using NPs are still not well established. This work investigates the effect of in-situ surface-modified silica nanoparticles (SiO2 NPs) on interfacial tension (IFT) and wettability behavior as a prevailing oil recovery mechanism. For this purpose, the nanoparticles have been synthesized via a one-step sol-gel method using surface-modification agents, including Triton X-100 (non-ionic surfactant) and polyethylene glycol (polymer), and characterized using various techniques. These results exhibit the well-defined spherical particles, particularly in the presence of Triton X-100 (TX-100), with particle diameter between 13 to 27 nm. To this end, SiO2 nanofluids were formed by dispersing nanoparticles (0.05 wt.%, 0.075 wt.%, 0.1 wt.%, and 0.2 wt.%) in 3 wt.% NaCl to study the impact of surface functionalization on the stability of the nanoparticle suspension. The optimal stability conditions were obtained at 0.1 wt.% SiO2 NPs at a basic pH of 10 and 9.5 for TX-100/ SiO2 and PEG/SiO nanofluids, respectively. Finally, the surface-treated SiO2 nanoparticles were found to change the wettability of treated (oil-wet) surface into water-wet by altering the contact angle from 130° to 78° (in case of TX-100/SiO2) measured against glass surface representing carbonate reservoir rock. IFT results also reveal that the surfactant treatment greatly reduced the oil-water IFT by 30%, compared to other applied NPs. These experimental results suggest that the use of surface-modified SiO2 nanoparticles could facilitate the displacement efficiency by reducing IFT and altering the wettability of carbonate reservoir towards water-wet, which is attributed to more homogeneity and better dispersion of surface-treated silica NPs compared to bare-silica NPs.
    Matched MeSH terms: Oils/isolation & purification*
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