Displaying publications 41 - 60 of 228 in total

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  1. Shear flow behaviour and emulsion-stabilizing effect of natural polysaccharide-protein gum in aqueous system and oil/water (O/W) emulsion
    Amid BT, Mirhosseini H
    Colloids Surf B Biointerfaces, 2013 Mar 1;103:430-40.
    PMID: 23261563 DOI: 10.1016/j.colsurfb.2012.11.015
    The main objective of the current work was to characterize the shear rheological flow behaviour and emulsifying properties of the natural biopolymer from durian seed. The present study revealed that the extraction condition significantly affected the physical and functional characteristics of the natural biopolymer from durian seed. The dynamic oscillatory test indicated that the biopolymer from durian seed showed more gel (or solid) like behaviour than the viscous (or liquid) like behaviour (G'>G″) at a relatively high concentration (20%) in the fixed frequency (0.1 Hz). This might be explained by the fact that the gum coils disentangle at low frequencies during the long period of oscillation, thus resulting in more gel like behaviour than the viscous like behaviour. The average droplet size of oil in water (O/W) emulsions stabilized by durian seed gum significantly varied from 0.42 to 7.48 μm. The results indicated that O/W emulsions showed significant different stability after 4 months storage. This might be interpreted by the considerable effect of the extraction condition on the chemical and molecular structure of the biopolymer, thus affecting its emulsifying capacity. The biopolymer extracted by using low water to seed (W/S) ratio at the low temperature under the alkaline condition showed a relatively high emulsifying activity in O/W emulsion.
    Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
  2. Casein nanomicelle as an emerging biomaterial-A comprehensive review
    Rehan F, Ahemad N, Gupta M
    Colloids Surf B Biointerfaces, 2019 Jul 01;179:280-292.
    PMID: 30981063 DOI: 10.1016/j.colsurfb.2019.03.051
    Casein nanomicelles, a major fraction of milk protein, are emerging as a novel drug delivery system owing to their various structural and functional properties. Casein is further divided into α-, β- and κ-casein, and to date various models have been proposed to describe casein structure, but still no definite structure presenting a detailed assembly of the casein micelle has been found. Thus far, the submicellar model and Horne and Holt model are the most accepted models. This article presents a detailed review of casein micelles and their fractions, and the physicochemical properties that account for their numerous applications in nutraceutics, pharmaceutics and cosmetics. Due to their nanosize and self-assembling nature, casein nanomicelles are considered as excellent delivery carriers to provide better bioavailability and stability of various compounds such as vitamins, oils, polyphenols, fattyacids and minerals. Their amphiphilic nature also provides a great opportunity to deliver hydrophobic bioactives in various drug delivery systems such as nanoparticles, nanomicelles, nanogels and nanoemulsions to improve drug binding and targeting.
    Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
  3. Recent Advances in Drug Delivery of Polymeric Nano-Micelles
    Aziz ZABA, Ahmad A, Mohd-Setapar SH, Hassan H, Lokhat D, Kamal MA, et al.
    Curr Drug Metab, 2017;18(1):16-29.
    PMID: 27654898 DOI: 10.2174/1389200217666160921143616
    In clinical studies, drugs with hydrophobic characteristic usually reflect low bioavailability, poor drug absorption, and inability to achieve the therapeutic concentration in blood. The production of poor solubility drugs, in abundance, by pharmaceutical industries calls for an urgent need to find the alternatives for resolving the above mentioned shortcomings. Poor water solubility drugs loaded with polymeric micelle seem to be the best alternative to enhance drugs solubility and bioavailability. Polymeric micelle, formed by self-assembled of amphiphilic block copolymers in aqueous environment, functioned as solubilizing agent for hydrophobic drug. This review discusses the fundamentals of polymeric micelle as drug carrier through representative literature, and demonstrates some applications in various clinical trials. The structure, characteristic, and formation of polymeric micelle have been discussed firstly. Next, this manuscript focuses on the potential of polymeric micelles as drug vehicle in oral, transdermal routes, and anti-cancer agent. Several results from previous studies have been reproduced in this review in order to prove the efficacy of the micelles in delivering hydrophobic drugs. Lastly, future strategies to broaden the application of polymeric micelles in pharmaceutical industries have been highlighted.
    Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
  4. Parametric Investigation of Batch Adsorption of Proteins onto Polymeric Particles
    Tan MX, Agyei D, Pan S, Danquah MK
    Curr Pharm Biotechnol, 2015;16(9):816-22.
    PMID: 26119365
    BACKGROUND: Effective bimolecular adsorption of proteins onto solid matrices is characterized by in-depth understanding of the biophysical features essential to optimize the adsorption performance.

    RESULTS: The adsorption of bovine serum albumin (BSA) onto anion-exchange Q-sepharose solid particulate support was investigated in batch adsorption experiments. Adsorption kinetics and isotherms were developed as a function of key industrially relevant parameters such as polymer loading, stirring speed, buffer pH, protein concentration and the state of protein dispersion (solid/aqueous) in order to optimize binding performance and adsorption capacity. Experimental results showed that the first order rate constant is higher at higher stirring speed, higher polymer loading, and under alkaline conditions, with a corresponding increase in equilibrium adsorption capacity. Increasing the stirring speed and using aqueous dispersion protein system increased the adsorption rate, but the maximum protein adsorption was unaffected. Regardless of the stirring speed, the adsorption capacity of the polymer was 2.8 mg/ml. However, doubling the polymer loading increased the adsorption capacity to 9.4 mg/ml.

    CONCLUSIONS: The result demonstrates that there exists a minimum amount of polymer loading required to achieve maximum protein adsorption capacity under specific process conditions.

    Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
  5. Guest-host Relationship of Cyclodextrin and its Pharmacological Benefits
    Alshati F, Alahmed TAA, Sami F, Ali MS, Majeed S, Murtuja S, et al.
    Curr Pharm Des, 2023;29(36):2853-2866.
    PMID: 37946351 DOI: 10.2174/0113816128266398231027100119
    Many methods, including solid dispersion, micellization, and inclusion complexes, have been employed to increase the solubility of potent drugs. Beta-cyclodextrin (βCD) is a cyclic oligosaccharide consisting of seven glucopyranoside molecules, and is a widely used polymer for formulating soluble inclusion complexes of hydrophobic drugs. The enzymatic activity of Glycosyltransferase or α-amylase converts starch or its derivatives into a mixture of cyclodextrins. The βCD units are characterized by α -(1-4) glucopyranose bonds. Cyclodextrins possess certain properties that make them very distinctive because of their toroidal or truncated cage-like supramolecular configurations with multiple hydroxyl groups at each end. This allowed them to encapsulate hydrophobic compounds by forming inclusion complexes without losing their solubility in water. Chemical modifications and newer derivatives, such as methylated βCD, more soluble hydroxyl propyl methyl βCD, and sodium salts of sulfobutylether-βCD, known as dexolve® or captisol®, have envisaged the use of CDs in various pharmaceutical, medical, and cosmetic industries. The successful inclusion of drug complexes has demonstrated improved solubility, bioavailability, drug resistance reduction, targeting, and penetration across skin and brain tissues. This review encompasses the current applications of β-CDs in improving the disease outcomes of antimicrobials and antifungals as well as anticancer and anti-tubercular drugs.
    Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
  6. Two new monofunctional platinum(II) dithiocarbamate complexes: phenanthriplatin-type axial protection, equatorial-axial conformational isomerism, and anticancer and DNA binding studies
    Imran M, Rehman ZU, Hogarth G, Tocher DA, Chaudhry GE, Butler IS, et al.
    Dalton Trans, 2020 Nov 10;49(43):15385-15396.
    PMID: 33140800 DOI: 10.1039/d0dt03018j
    The syntheses of two platinum(ii) dithiocarbamate complexes (1 and 2) that show quinoplatin- and phenanthriplatin-type axial protection of the Pt-plane are described. The Pt-plane of complex 2 is axially more protected than that of complex 1. Furthermore, both complexes adopt two different stereochemical conformations in the solid state (based on single-crystal X-ray structures) owing to the structurally flexible piperazine backbone; i.e., C-e,e-Anti (1) and C-e,a-Syn (2), where "C" stands for the chair configuration, "e" and "a" stand for the equatorial and axial positions and "Anti" (opposite side) and "Syn" (same side) represent the relative orientations in space of the terminal substituents on the piperazine ring. In complex 2, the C-e,a-Syn conformation may provide additional steric hindrance to the Pt-plane. Despite the lower lipophilicity of 2 as compared to that of 1, the in vitro anticancer action against selected cancer cell lines is better for the former revealing the superior role of the axial protection over lipophilicity in modulating anticancer activity. The activity against the cancer promoting protein NF-κB signifies that the mode of cancer cell death may be the result of hindering the activity of NF-κB in the initiation of apoptosis. The apoptotic mode of cell death has been established earlier in a study using Annexin V-FITC. Finally, DNA binding studies revealed that the complex-DNA adduct formation is spontaneous and the mode of interaction is non-intercalative (electrostatic/covalent).
    Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
  7. Fulltext Adsorption and in vitro release study of curcumin form polyethyleneglycol functionalized multi walled carbon nanotube: kinetic and isotherm study
    Koupaei Malek S, Gabris MA, Hadi Jume B, Baradaran R, Aziz M, Karim KJBA, et al.
    Daru, 2019 Jun;27(1):9-20.
    PMID: 30554368 DOI: 10.1007/s40199-018-0232-2
    Polyethylene glycol functionalized with oxygenated multi-walled carbon nanotubes (O-PEG-MWCNTs) as an efficient nanomaterial for the in vitro adsorption/release of curcumin (CUR) anticancer agent. The synthesized material was morphologically characterized using scanning electron microscopy, Fourier transform infrared spectroscopy and transmission electron microscopy. In addition, the CUR adsorption process was assessed with kinetic and isotherm models fitting well with pseudo-second order and Langmuir isotherms. The results showed that the proposed O-PEG-MWCNTs has a high adsorption capacity for CUR (2.0 × 103 mg/g) based on the Langmuir model. The in vitro release of CUR from O-PEG-MWCNTs was studied in simulating human body fluids with different pHs (ABS pH 5, intestinal fluid pH 6.6 and body fluid pH 7.4). Lastly, to confirm the success compliance of the O-PEG-MWCNT nanocomposite as a drug delivery system, the parameters affecting the CUR release such as temperature and PEG content were investigated. As a result, the proposed nanocomposite could be used as an efficient carrier for CUR delivery with an enhanced prolonged release property. Graphical Abstract ᅟ.
    Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
  8. Fulltext Supporting data for identification of biosurfactant-producing bacteria isolated from agro-food industrial effluent
    Fulazzaky MA, Abdullah S, Salim MR
    Data Brief, 2016 Jun;7:834-8.
    PMID: 27077083 DOI: 10.1016/j.dib.2016.03.058
    The goal of this study was to identify the biosurfactant-producing bacteria isolated from agro-food industrial effluet. The identification of the potential bacterial strain using a polymerase chain reaction of the 16S rRNA gene analysis was closely related to Serratia marcescens with its recorded strain of SA30 "Fundamentals of mass transfer and kinetics for biosorption of oil and grease from agro-food industrial effluent by Serratia marcescens SA30" (Fulazzaky et al., 2015) [1]; however, many biochemical tests have not been published yet. The biochemical tests of biosurfactant production, haemolytic assay and cell surface hydrophobicity were performed to investigate the beneficial strain of biosurfactant-producing bacteria. Here we do share data collected from the biochemical tests to get a better understanding of the use of Serratia marcescens SA30 to degrade oil, which contributes the technical features of strengthening the biological treatment of oil-contaminated wastewater in tropical environments.
    Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
  9. Fulltext Data for molecular recognition between polyamide thin film composite on the polymeric subtract by molecular dynamic
    Wan Jusoh WZA, Abdul Rahman S, Ahmad AL, Mohd Mokhtar N
    Data Brief, 2019 Jun;24:103910.
    PMID: 31193576 DOI: 10.1016/j.dib.2019.103910
    This paper focus to examine the best molecular interaction between Polyamide Thin Film Composite (PA TFC) layers with different properties of the support membrane. The support membrane of Nylon 66 (N66) and Polyvinylidene fluoride (PVDF) was chosen to represent the hydrophilic and hydrophobic model respectively in the Molecular Dynamic (MD) simulation. The Condensed-Phase Optimized Molecular Potential for Atomistic Simulation Studies (COMPASS) force field was used with the total simulation runs were set 1000 picoseconds run production ensembles. The temperature and pressure set for both ensembles were 298 K and 1 atm respectively. The validity of our model densities data was check and calculated where the deviation must be less than 6%. The comparison between hydrophobic and hydrophilic of the support membrane data was examined by the distance and magnitude of intensity of the Radial Distribution Function (RDF's) trends.
    Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
  10. Polymer-wrapped single-walled carbon nanotubes: a transformation toward better applications in healthcare
    Chik MW, Hussain Z, Zulkefeli M, Tripathy M, Kumar S, Majeed ABA, et al.
    Drug Deliv Transl Res, 2019 04;9(2):578-594.
    PMID: 29594914 DOI: 10.1007/s13346-018-0505-9
    Carbon nanotubes (CNTs) possess outstanding properties that could be useful in several technological, drug delivery, and diagnostic applications. However, their unique physical and chemical properties are hindered due to their poor solubility. This article review's the different ways and means of solubility enhancement of single-wall carbon nanotubes (SWNTs). The advantages of SWNTs over the multi-walled carbon nanotubes (MWNTs) and the method of non-covalent modification for solubility enhancement has been the key interest in this review. The review also highlights a few examples of dispersant design. The review includes some interesting utility of SWNTs being wrapped with polymer especially in biological media that could mediate proper drug delivery to target cells. Further, the use of wrapped SWNTs with phospholipids, nucleic acid, and amphiphillic polymers as biosensors is of research interest. The review aims at summarizing the developments relating to wrapped SWNTs to generate further research prospects in healthcare.
    Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
  11. Emerging era of "somes": polymersomes as versatile drug delivery carrier for cancer diagnostics and therapy
    Sharma AK, Prasher P, Aljabali AA, Mishra V, Gandhi H, Kumar S, et al.
    Drug Deliv Transl Res, 2020 Oct;10(5):1171-1190.
    PMID: 32504410 DOI: 10.1007/s13346-020-00789-2
    Over the past two decades, polymersomes have been widely investigated for the delivery of diagnostic and therapeutic agents in cancer therapy. Polymersomes are stable polymeric vesicles, which are prepared using amphiphilic block polymers of different molecular weights. The use of high molecular weight amphiphilic copolymers allows for possible manipulation of membrane characteristics, which in turn enhances the efficiency of drug delivery. Polymersomes are more stable in comparison with liposomes and show less toxicity in vivo. Furthermore, their ability to encapsulate both hydrophilic and hydrophobic drugs, significant biocompatibility, robustness, high colloidal stability, and simple methods for ligands conjugation make polymersomes a promising candidate for therapeutic drug delivery in cancer therapy. This review is focused on current development in the application of polymersomes for cancer therapy and diagnosis. Graphical abstract.
    Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
  12. Fulltext Effect of surfactant and surfactant blends on pseudoternary phase diagram behavior of newly synthesized palm kernel oil esters
    Mahdi ES, Sakeena MH, Abdulkarim MF, Abdullah GZ, Sattar MA, Noor AM
    Drug Des Devel Ther, 2011;5:311-23.
    PMID: 21792294 DOI: 10.2147/DDDT.S15698
    The purpose of this study was to select appropriate surfactants or blends of surfactants to study the ternary phase diagram behavior of newly introduced palm kernel oil esters.
    Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
  13. Recent advances in gel technologies for topical and transdermal drug delivery
    Rehman K, Zulfakar MH
    Drug Dev Ind Pharm, 2014 Apr;40(4):433-40.
    PMID: 23937582 DOI: 10.3109/03639045.2013.828219
    Transdermal drug delivery systems are a constant source of interest because of the benefits that they afford in overcoming many drawbacks associated with other modes of drug delivery (i.e. oral, intravenous). Because of the impermeable nature of the skin, designing a suitable drug delivery vehicle that penetrates the skin barrier is challenging. Gels are semisolid formulations, which have an external solvent phase, may be hydrophobic or hydrophilic in nature, and are immobilized within the spaces of a three-dimensional network structure. Gels have a broad range of applications in food, cosmetics, biotechnology, pharmatechnology, etc. Typically, gels can be distinguished according to the nature of the liquid phase, for example, organogels (oleogels) contain an organic solvent, and hydrogels contain water. Recent studies have reported other types of gels for dermal drug application, such as proniosomal gels, emulgels, bigels and aerogels. This review aims to introduce the latest trends in transdermal drug delivery via traditional hydrogels and organogels and to provide insight into the latest gel types (proniosomal gels, emulgels, bigels and aerogels) as well as recent technologies for topical and transdermal drug delivery.
    Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
  14. In vitro and in vivo evaluation of hydrophilic and hydrophobic polymers-based nicorandil-loaded peroral tablet compared with its once-daily commercial sustained-release tablet
    Tamilvanan S, Venkatesh Babu R, Nappinai A, Sivaramakrishnan G
    Drug Dev Ind Pharm, 2011 Apr;37(4):436-45.
    PMID: 20923389 DOI: 10.3109/03639045.2010.521161
    Hydrophilic and hydrophobic polymer-based nicorandil (10 mg)-loaded peroral tablets were prepared using the wet granulation technique. The influence of varying amounts of hydroxypropyl methylcellulose (HPMC) (30-50 mg), ethylcellulose (2-4 mg), microcrystalline cellulose (5-20 mg) and Aerosil® (5-12 mg) in conjunction with the constant amounts (3 mg) of glidant and lubricant (magnesium stearate and talc) on the in vitro performances of the tablets (hardness, friability, weight variation, thickness uniformity, drug content, and drug release behavior) were investigated.
    Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
  15. Influence of bentonite in polymer membranes for effective treatment of car wash effluent to protect the ecosystem
    Kiran SA, Arthanareeswaran G, Thuyavan YL, Ismail AF
    Ecotoxicol Environ Saf, 2015 Nov;121:186-92.
    PMID: 25869419 DOI: 10.1016/j.ecoenv.2015.04.001
    In this study, modified polyethersulfone (PES) and cellulose acetate (CA) membranes were used in the treatment of car wash effluent using ultrafiltration. Hydrophilic sulfonated poly ether ether ketone (SPEEK) and bentonite as nanoclay were used as additives for the PES and CA membrane modification. Performances of modified membranes were compared with commercial PES membrane with 10kDa molecular weight cut off (MWCO). The influencing parameters like stirrer speed (250-750rpm) and transmembrane pressure (100-600kPa) (TMP) were varied and their effects were studied as a function of flux. In the treatment of car wash effluent, a higher permeate flux of 52.3L/m(2)h was obtained for modified CA membrane at TMP of 400kPa and stirrer speed of 750rpm. In comparison with modified PES membrane and commercial PES membrane, modified CA membranes showed better performance in terms of flux and flux recovery ratio. The highest COD removal (60%) was obtained for modified CA membrane and a lowest COD removal (47%) was observed for commercial PES membrane. The modified membranes were better at removing COD, turbidity and maintained more stable flux than commercial PES membrane, suggesting they will provide better economic performance in car wash effluent reclamation.
    Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
  16. Mechanistic behaviour of Chlorella vulgaris biofilm formation onto waste organic solid support used to treat palm kernel expeller in the recent Anthropocene
    Rawindran H, Syed R, Alangari A, Khoo KS, Lim JW, Sahrin NT, et al.
    Environ Res, 2023 Apr 01;222:115352.
    PMID: 36716802 DOI: 10.1016/j.envres.2023.115352
    The capacity to maximize the proliferation of microalgal cells by means of topologically textured organic solid surfaces under various pH gave rise to the fundamental biophysical analysis of cell-surface attachment in this study. The substrate used in analysis was palm kernel expeller (PKE) in which the microalgal cells had adhered onto its surface. The findings elucidated the relevance of surface properties in terms of surface wettability and surface energy in relation to the attached microalgal growth with pH as the limiting factor. The increase in hydrophobicity of PKE-microalgae attachment was able to facilitate the formation of biofilm better. The pH 5 and pH 11 were found to be the conditions with highest and lowest microalgal growths, respectively, which were in tandem with the highest contact angle value at pH 5 and conversely for pH 11. The work of attachment (Wcs) had supported the derived model with positive values being attained for all the pH conditions, corroborating the thermodynamic feasibility. Finally, this study had unveiled the mechanism of microalgal attachment onto the surface of PKE using the aid of extracellular polymeric surfaces (EPS) from microalgae. Also, the hydrophobic nature of PKE enabled excellent attachment alongside with nutrients for microalgae to grow and from layer-by-layer (LbL) assembly. This assembly was then isolated using organosolv method by means of biphasic solvents, namely, methanol and chloroform, to induce detachment.
    Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
  17. A novel cultivation platform of duckweed (Lemna minor) via application of beeswax superhydrophobic coatings
    Chua MX, Cheah YT, Tan WH, Chan DJC
    Environ Res, 2023 May 01;224:115544.
    PMID: 36822535 DOI: 10.1016/j.envres.2023.115544
    Conventional establishment of laboratory cultures of duckweed Lemna minor are prepared in beakers, Erlenmeyer flasks or Schott bottles. These conventional cultivation methods limit the available surface area for growth which then causes layering of fronds that reduces the efficiency of plants in sunlight capturing. Here, acrylic sheets were spray-coated with a superhydrophobic (SHP) beeswax suspension and these coated acrylic sheets were used as a novel cultivation platform for L. minor. L. minor was grown for 7 days in conventional glass jar which acted as the control and were compared to SHP coated acrylic (SHPA) and SHP coated acrylic with aluminium mesh centrally placed (SHPAM) at similar duration and cultivation conditions. Addition of mesh was to entrap the plantlets and fixed the plantlets' position on the growing platform. The effects of cultivation platforms on growth rate and biochemical compositions of L. minor were monitored. The highest biomass growth was obtained from SHPA cultivation where the relative growth rate (RGR) was 0.0909 ± 0.014 day-1 and the RGR was 2.17 times higher than the control. Moreover, L. minor harvested from SHPA displayed the highest values in total protein content, total carbohydrates content and crude lipid percentage. The values were 156.04 ± 12.13 mg/g, 94.75 ± 9.02 mg/g and 7.09 ± 1.14% respectively. However, the control showed the highest total chlorophyll content which was 0.7733 ± 0.042 mg/g FW. Although SHPA obtained a slightly lower chlorophyll content than the control, this growing platform is still promising as it displayed the highest growth rate as well as other biochemical composition. Hence, this study proved that the proposed method that applied superhydrophobic properties in cultivation of L. minor provided a larger surface area for L. minor to grow, which then resulted in a greater biomass production while simultaneously maintaining the quality of the biochemical compositions of duckweeds.
    Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
  18. Impact of biological filtrations for organic micropollutants and polyfluoroalkyl substances removal from secondary effluent
    Pramanik BK, Pramanik SK, Suja F
    Environ Technol, 2016 Aug;37(15):1857-64.
    PMID: 26695189 DOI: 10.1080/09593330.2015.1134677
    The impact of biological activated carbon (BAC), sand filtration (SF) and biological aerated filter (BAF) for removal of the selected organic micropollutants and polyfluoroalkyl substances (PFASs) from secondary effluent was studied. BAC led to greater removal of dissolved organic carbon (43%) than BAF (30%) which in turn was greater than SF (24%). All biological filtration systems could effectively remove most of the selected organic micropollutants, and there was a greater removal of these micropollutants by BAC (76-98%) than BAF (70-92%) or SF (68-90%). It was found that all treatment was effective for removal of the hydrophobic (log D > 3.2) and readily biodegradable organic micropollutants. The major mechanism for the removal of these molecules was biodegradation by the micro-organism and sorption by the biofilm. Compared to organic micropollutants removal, there was a lower removal of PFASs by all treatments, and BAF and SF had a considerably lower removal than BAC treatment. The better removal for all molecule types by BAC was due to additional adsorption capacity by the activated carbon. This study demonstrated that the BAC process was most effective in removing organic micropollutants present in the secondary effluent.
    Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
  19. Facile modulation of enantioselectivity of thermophilic Geobacillus zalihae lipase by regulating hydrophobicity of its Q114 oxyanion
    Abdul Wahab R, Basri M, Raja Abdul Rahman RN, Salleh AB, Abdul Rahman MB, Leow TC
    Enzyme Microb Technol, 2016 Nov;93-94:174-181.
    PMID: 27702478 DOI: 10.1016/j.enzmictec.2016.08.020
    Site-directed mutagenesis of the oxyanion-containing amino acid Q114 in the recombinant thermophilic T1 lipase previously isolated from Geobacillus zalihae was performed to elucidate its role in the enzyme's enantioselectivity and reactivity. Substitution of Q114 with a hydrophobic methionine to yield mutant Q114M increased enantioselectivity (3.2-fold) and marginally improved reactivity (1.4-fold) of the lipase in catalysing esterification of ibuprofen with oleyl alcohol. The improved catalytic efficiency of Q114L was concomitant with reduced flexibility in the active site while the decreased enantioselectivity of Q114L could be directly attributed to diminished electrostatic repulsion of the substrate carboxylate ion that rendered partial loss in steric hindrance and thus enantioselectivity. The highest E-values for both Q114L (E-value 14.6) and Q114M (E-value 48.5) mutant lipases were attained at 50°C, after 12-16h, with a molar ratio of oleyl alcohol to ibuprofen of 1.5:1 and at 2.0% (w/v) enzyme load without addition of molecular sieves. Pertinently, site-directed mutagenesis on the Q114 oxyanion of T1 resulted in improved enantioselectivity and such approach may be applicable to other lipases of the same family. We demonstrated that electrostatic repulsion phenomena could affect flexibility/rigidity of the enzyme-substrate complex, aspects vital for enzyme activity and enantioselectivity of T1.
    Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
  20. Fulltext Ultraviolet A and Ultraviolet C Light-Induced Reduction of Surface Hydrocarbons on Titanium Implants
    Naauman Z, Rajion ZAB, Maliha S, Hariy P, Muhammad QS, Noor HAR
    Eur J Dent, 2019 Feb;13(1):114-118.
    PMID: 31170762 DOI: 10.1055/s-0039-1688741
    OBJECTIVE: The carbon, titanium, and oxygen levels on titanium implant surfaces with or without ultraviolet (UV) pretreatment were evaluated at different wavelengths through X-ray photoelectron spectroscopy (XPS).

    MATERIALS AND METHODS: This interventional experimental study was conducted on nine Dio UFII implants with hybrid sandblasted and acid-etched (SLA) surface treatments, divided equally into three groups. Control group A samples were not given UV irradiation, while groups B and C samples were given UVA (382 nm, 25 mWcm2) and UVC (260 nm, 15 mWcm2) irradiation, respectively. The atomic ratio of carbon, titanium, and oxygen was compared through XPS.

    RESULTS: Mean carbon-to-titanium ratio and C1 peaks considerably increased in Group A compared to those in experimental Groups B and C. The intensity of Ti2p and O1s peaks was more pronounced for group C compared to that for groups A and B.

    CONCLUSIONS: Although the decrease in surface hydrocarbons was the same in both UV-treated groups, the peak intensity of oxygen increased in the UVC-treated group. Thus, it can be concluded that compared with UVA irradiation, UVC irradiation has the potential to induce more hydrophilicity on SLA-coated implants.

    Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
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