Displaying publications 2121 - 2140 of 10379 in total

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  1. Predicting the fluorescent enhancement rate by gold and silver nanospheres using finite-difference time-domain analysis
    Centeno A, Xie F, Alford N
    IET Nanobiotechnol, 2013 Jun;7(2):50-8.
    PMID: 24046905
    Metal-induced fluorescence enhancement (MIFE) is a promising strategy for increasing the sensitivity of fluorophores used in biological sensors. This study uses the finite-difference time-domain technique to predict the fluorescent enhancement rate of a fluorophore molecule in close proximity to a gold or silver spherical nanoparticle. By considering commercially available fluorescent dyes the computed results are compared with the published experimental data. The results show that MIFE is a complex coupling process between the fluorophore molecule and the metal nanoparticle. Nevertheless using computational electromagnetic techniques to perform calculations it is possible to calculate, with reasonable accuracy, the fluorescent enhancement. Using this methodology it will be possible to consider different shaped metal nanoparticles and any supporting substrate material in the future, an important step in building reliable biosensors capable of detecting low levels of proteins tagged with fluorescence molecules.
    Matched MeSH terms: Fluorescent Dyes/chemistry*; Gold/chemistry*; Silver/chemistry*; Metal Nanoparticles/chemistry; Nanospheres/chemistry*
  2. Fulltext Improvement of physicochemical characteristics of monoepoxide linoleic acid ring opening for biolubricant base oil
    Salimon J, Salih N, Abdullah BM
    J Biomed Biotechnol, 2011;2011:196565.
    PMID: 22131799 DOI: 10.1155/2011/196565
    For environmental reasons, a new class of environmentally acceptable and renewable biolubricant based on vegetable oils is available. In this study, oxirane ring opening reaction of monoepoxide linoleic acid (MEOA) was done by nucleophilic addition of oleic acid (OA) with using p-toluene sulfonic acid (PTSA) as a catalyst for synthesis of 9(12)-hydroxy-10(13)-oleoxy-12(9)-octadecanoic acid (HYOOA) and the physicochemical properties of the resulted HYOOA are reported to be used as biolubricant base oils. Optimum conditions of the experiment using D-optimal design to obtain high yield% of HYOOA and lowest OOC% were predicted at OA/MEOA ratio of 0.30 : 1 (w/w), PTSA/MEOA ratio of 0.50 : 1 (w/w), reaction temperature at 110°C, and reaction time at 4.5 h. The results showed that an increase in the chain length of the midchain ester resulted in the decrease of pour point (PP) -51°C, increase of viscosity index (VI) up to 153, and improvement in oxidative stability (OT) to 180.94°C.
    Matched MeSH terms: Linoleic Acids/chemistry*; Plant Oils/chemistry*; Toluene/chemistry; Oleic Acid/chemistry*; Lubricants/chemistry
  3. Fulltext A new electrochemical sensor based on task-specific ionic liquids-modified palm shell activated carbon for the determination of mercury in water samples
    Abu Ismaiel A, Aroua MK, Yusoff R
    Sensors (Basel), 2014 Jul 21;14(7):13102-13.
    PMID: 25051034 DOI: 10.3390/s140713102
    In this study, a potentiometric sensor composed of palm shell activated carbon modified with trioctylmethylammonium thiosalicylate (TOMATS) was used for the potentiometric determination of mercury ions in water samples. The proposed potentiometric sensor has good operating characteristics towards Hg (II), including a relatively high selectivity; a Nernstian response to Hg (II) ions in a concentration range of 1.0 × 10(-9) to 1.0 × 10(-2) M, with a detection limit of 1 × 10(-10) M and a slope of 44.08 ± 1.0 mV/decade; and a fast response time (~5 s). No significant changes in electrode potential were observed when the pH was varied over the range of 3-9. Additionally, the proposed electrode was characterized by good selectivity towards Hg (II) and no significant interferences from other cationic or anionic species.
    Matched MeSH terms: Carbon/chemistry*; Ions/chemistry; Mercury/chemistry*; Water/chemistry; Ionic Liquids/chemistry*
  4. Fulltext Molecular dynamics simulation of palmitate ester self-assembly with diclofenac
    Abedi Karjiban R, Basri M, Abdul Rahman MB, Salleh AB
    Int J Mol Sci, 2012;13(8):9572-9583.
    PMID: 22949816 DOI: 10.3390/ijms13089572
    Palm oil-based esters (POEs) are unsaturated and non-ionic esters with a great potential to act as chemical penetration enhancers and drug carriers for transdermal drug nano-delivery. A ratio of palmitate ester and nonionic Tween80 with and without diclofenac acid was chosen from an experimentally determined phase diagram. Molecular dynamics simulations were performed for selected compositions over a period of 15 ns. Both micelles showed a prolate-like shape, while adding the drug produced a more compact micellar structure. Our results proposed that the drug could behave as a co-surfactant in our simulated model.
    Matched MeSH terms: Diclofenac/chemistry*; Esters/chemistry*; Palmitates/chemistry*; Polysorbates/chemistry; Surface-Active Agents/chemistry*
  5. Fulltext Carbon nanodots as molecular scaffolds for development of antimicrobial agents
    Ngu-Schwemlein M, Chin SF, Hileman R, Drozdowski C, Upchurch C, Hargrove A
    Bioorg Med Chem Lett, 2016 Apr 01;26(7):1745-9.
    PMID: 26923697 DOI: 10.1016/j.bmcl.2016.02.047
    We report the potential of carbon nanodots (CNDs) as a molecular scaffold for enhancing the antimicrobial activities of small dendritic poly(amidoamines) (PAMAM). Carbon nanodots prepared from sago starch are readily functionalized with PAMAM by using N-ethyl-N'-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS). Electron microscopy images of these polyaminated CNDs show that they are approximately 30-60nm in diameter. Infrared and fluorescence spectroscopy analyses of the water-soluble material established the presence of the polyamidoaminated moiety and the intrinsic fluorescence of the nanodots. The polyaminated nanodots (CND-PAM1 and CND-PAM2) exhibit in vitro antimicrobial properties, not only to non-multidrug resistant bacteria but also to the corresponding Gram-negative multidrug bacteria. Their minimum inhibitory concentration (MIC) ranges from 8 to 64μg/mL, which is much lower than that of PAMAM G1 or the non-active PAMAM G0 and CNDs. Additionally, they show synergistic effect in combination with tetracycline or colistin. These preliminary results imply that CNDs can serve as a promising scaffold for facilitating the rational design of antimicrobial materials for combating the ever-increasing threat of antibiotic resistance. Moreover, their fluorescence could be pertinent to unraveling their mode of action for imaging or diagnostic applications.
    Matched MeSH terms: Anti-Bacterial Agents/chemistry*; Carbon/chemistry*; Succinimides/chemistry; Nanostructures/chemistry; Dendrimers/chemistry*
  6. Fulltext Reduced photoinhibition under low irradiance enhanced Kacip Fatimah (Labisia pumila Benth) secondary metabolites, phenyl alanine lyase and antioxidant activity
    Ibrahim MH, Jaafar HZE
    Int J Mol Sci, 2012;13(5):5290-5306.
    PMID: 22754297 DOI: 10.3390/ijms13055290
    A randomized complete block design experiment was designed to characterize the relationship between production of total flavonoids and phenolics, anthocyanin, photosynthesis, maximum efficiency of photosystem II (Fv/Fm), electron transfer rate (Fm/Fo), phenyl alanine lyase activity (PAL) and antioxidant (DPPH) in Labisia pumila var. alata, under four levels of irradiance (225, 500, 625 and 900 μmol/m(2)/s) for 16 weeks. As irradiance levels increased from 225 to 900 μmol/m(2)/s, the production of plant secondary metabolites (total flavonoids, phenolics and antocyanin) was found to decrease steadily. Production of total flavonoids and phenolics reached their peaks under 225 followed by 500, 625 and 900 μmol/m(2)/s irradiances. Significant positive correlation of production of total phenolics, flavonoids and antocyanin content with Fv/Fm, Fm/Fo and photosynthesis indicated up-regulation of carbon-based secondary metabolites (CBSM) under reduced photoinhibition on the under low light levels condition. At the lowest irradiance levels, Labisia pumila extracts also exhibited a significantly higher antioxidant activity (DPPH) than under high irradiance. The improved antioxidative activity under low light levels might be due to high availability of total flavonoids, phenolics and anthocyanin content in the plant extract. It was also found that an increase in the production of CBSM was due to high PAL activity under low light, probably signifying more availability of phenylalanine (Phe) under this condition.
    Matched MeSH terms: Anthocyanins/chemistry; Antioxidants/chemistry; Flavonoids/chemistry; Phenols/chemistry; Primulaceae/chemistry
  7. Fulltext Sargassum Seaweed as a Source of Anti-Inflammatory Substances and the Potential Insight of the Tropical Species: A Review
    Saraswati, Giriwono PE, Iskandriati D, Tan CP, Andarwulan N
    Mar Drugs, 2019 Oct 17;17(10).
    PMID: 31627414 DOI: 10.3390/md17100590
    Sargassum is recognized both empirically and scientifically as a potential anti-inflammatory agent. Inflammation is an important response in the body that helps to overcome various challenges to body homeostasis such as microbial infections, tissue stress, and certain injuries. Excessive and uncontrolled inflammatory conditions can affect the pathogenesis of various diseases. This review aims to explore the potential of Sargassum's anti-inflammatory activity, not only in crude extracts but also in sulfated polysaccharides and purified compounds. The tropical region has a promising availability of Sargassum biomass because its climate allows for the optimal growth of seaweed throughout the year. This is important for its commercial utilization as functional ingredients for both food and non-food applications. To the best of our knowledge, studies related to Sargassum's anti-inflammatory activity are still dominated by subtropical species. Studies on tropical Sargassum are mainly focused on the polysaccharides group, though there are some other potentially bioactive compounds such as polyphenols, terpenoids, fucoxanthin, fatty acids and their derivatives, typical polar lipids, and other groups. Information on the modulation mechanism of Sargassum's bioactive compounds on the inflammatory response is also discussed here, but specific mechanisms related to the interaction between bioactive compounds and targets in cells still need to be further studied.
    Matched MeSH terms: Anti-Inflammatory Agents/chemistry*; Polysaccharides/chemistry; Seaweed/chemistry*; Sargassum/chemistry*; Polyphenols/chemistry
  8. How Important is the Metal-free Catalytic Knoevenagel Reaction in Medicinal Chemistry? An Updated Review
    Johari S, Johan MR, Khaligh NG
    Curr Med Chem, 2024;31(27):4286-4311.
    PMID: 38243980 DOI: 10.2174/0109298673260463231122074253
    The Knoevenagel condensation is a powerful and primary step for the development of carbon-carbon bond transformations. These condensations offer versatile products/ intermediates for diverse uses in polymers, cosmetics, chemical industries, and medicinal chemistry. Various homogenous and heterogenous catalysts have been found to promote the Knoevenagel condensation reaction, both environmentally and economically. Due to their attractive use in the production of pharmaceutical drugs, they are proven to be the main force that drives the synthesis involving numerous multi-component and multistep reactions. The present study, therefore, aims to summarise reported Knoevenagel condensation reactions using metal-free catalysts resulting in pharmaceutically useful compounds with anti-cancer, anti-tumor, anti-oxidant, anti-malarial, anti-diabetic, and anti- bacterial activities. By considering factors like their structure-activity relationships (SARs), the reaction conditions, and the steps involved, as well as the advantages and limitations of the particular approach, we also provide a general framework and direction in order to achieve superior characteristics of the catalyst.
    Matched MeSH terms: Anti-Bacterial Agents/chemistry; Antimalarials/chemistry; Antineoplastic Agents/chemistry; Chemistry, Pharmaceutical*
  9. Design and Evaluation of Microemulsion-Based Drug Delivery Systems for Biofilm-Based Infection in Burns
    Biswas A, A JM, Lewis SA, Raja S, Paul A, Ghosal K, et al.
    AAPS PharmSciTech, 2024 Sep 05;25(7):203.
    PMID: 39237802 DOI: 10.1208/s12249-024-02909-4
    Normal skin is the first line of defense in the human body. A burn injury makes the skin susceptible to bacterial infection, thereby delaying wound healing and ultimately leading to sepsis. The chances of biofilm formation are high in burn wounds due to the presence of avascular necrotic tissue. The most common pathogen to cause burn infection and biofilm is Pseudomonas aeruginosa. The purpose of this study was to create a microemulsion (ME) formulation for topical application to treat bacterial burn infection. In the present study, tea tree oil was used as the oil phase, Tween 80 and transcutol were used as surfactants, and water served as the aqueous phase. Pseudo ternary phase diagrams were used to determine the design space. The ranges of components as suggested by the design were chosen, optimization of the microemulsion was performed, and in vitro drug release was assessed. Based on the characterization studies performed, it was found that the microemulsion were formulated properly, and the particle size obtained was within the desired microemulsion range of 10 to 300 nm. The I release study showed that the microemulsion followed an immediate release profile. The formulation was further tested based on its ability to inhibit biofilm formation and bacterial growth. The prepared microemulsion was capable of inhibiting biofilm formation.
    Matched MeSH terms: Chemistry, Pharmaceutical/methods; Polysorbates/chemistry; Surface-Active Agents/chemistry; Tea Tree Oil/chemistry
  10. Fulltext Photocatalysis and photoelectrochemical properties of tungsten trioxide nanostructured films
    Lai CW
    ScientificWorldJournal, 2014;2014:843587.
    PMID: 24782669 DOI: 10.1155/2014/843587
    Tungsten trioxide (WO₃) possesses a small band gap energy of 2.4-2.8 eV and is responsive to both ultraviolet and visible light irradiation including strong absorption of the solar spectrum and stable physicochemical properties. Thus, controlled growth of one-dimensional (1D) WO₃ nanotubular structures with desired length, diameter, and wall thickness has gained significant interest. In the present study, 1D WO₃ nanotubes were successfully synthesized via electrochemical anodization of tungsten (W) foil in an electrolyte composed of 1 M of sodium sulphate (Na₂SO₄) and ammonium fluoride (NH₄F). The influence of NH₄F content on the formation mechanism of anodic WO₃ nanotubular structure was investigated in detail. An optimization of fluoride ions played a critical role in controlling the chemical dissolution reaction in the interface of W/WO₃. Based on the results obtained, a minimum of 0.7 wt% of NH₄F content was required for completing transformation from W foil to WO₃ nanotubular structure with an average diameter of 85 nm and length of 250 nm within 15 min of anodization time. In this case, high aspect ratio of WO₃ nanotubular structure is preferred because larger active surface area will be provided for better photocatalytic and photoelectrochemical (PEC) reactions.
    Matched MeSH terms: Quaternary Ammonium Compounds/chemistry; Electrochemistry/instrumentation; Electrochemistry/methods; Electrolytes/chemistry; Fluorides/chemistry; Hydrogen/chemistry; Oxides/chemistry*; Sulfates/chemistry; Tungsten/chemistry*; Water/chemistry; Nanostructures/chemistry*
  11. Fulltext Antioxidant and cytoprotective activities of Piper betle, Areca catechu, Uncaria gambir and betel quid with and without calcium hydroxide
    Sazwi NN, Nalina T, Abdul Rahim ZH
    BMC Complement Altern Med, 2013;13:351.
    PMID: 24330738 DOI: 10.1186/1472-6882-13-351
    Betel quid chewing is a popular habit in Southeast Asia. It is believed that chewing betel quid could reduce stress, strengthen teeth and maintain oral hygiene. The aim of this study was to investigate the antioxidant and cytoprotective activities of each of the ingredients of betel quid and compared with betel quid itself (with and without calcium hydroxide). The correlation of their cytoprotective and antioxidant activities with phenolic content was also determined.
    Matched MeSH terms: Antioxidants/chemistry; Areca/chemistry*; Calcium Hydroxide/chemistry*; Nuts/chemistry; Phenols/chemistry; Plant Extracts/chemistry; Plant Leaves/chemistry; Piper betle/chemistry*; Uncaria/chemistry*
  12. Carboxymethyl cellulose wafers containing antimicrobials: a modern drug delivery system for wound infections
    Ng SF, Jumaat N
    Eur J Pharm Sci, 2014 Jan 23;51:173-9.
    PMID: 24076463 DOI: 10.1016/j.ejps.2013.09.015
    Lyophilised wafers have been shown to have potential as a modern dressing for mucosal wound healing. The wafer absorbs wound exudates and transforms into a gel, thus providing a moist environment which is essential for wound healing. The objective of this study was to develop a carboxymethyl cellulose wafer containing antimicrobials to promote wound healing and treat wound infection. The pre-formulation studies began with four polymers, sodium carboxymethyl cellulose (NaCMC), methylcellulose (MC), sodium alginate and xanthan gum, but only NaCMC and MC were chosen for further investigation. The wafers were characterised by physical assessments, solvent loss, microscopic examination, swelling and hydration properties, drug content uniformity, drug release and efficacy of antimicrobials. Three of the antimicrobials, neomycin trisulphate salt hydrate, sulphacetamide sodium and silver nitrate, were selected as model drugs. Among the formulations, NaCMC wafer containing neomycin trisulphate exhibited the most desirable wound dressing characteristics (i.e., flexibility, sponginess, uniform wafer texture, high content drug uniformity) with the highest in vitro drug release and the greatest inhibition against both Gram positive and Gram negative bacteria. In conclusion, we successfully developed a NaCMC lyophilised wafer containing antimicrobials, and this formulation has potential for use in mucosal wounds infected with bacteria.
    Matched MeSH terms: Alginates/chemistry; Anti-Infective Agents/chemistry*; Carboxymethylcellulose Sodium/chemistry*; Chemistry, Pharmaceutical/methods; Hexuronic Acids/chemistry; Methylcellulose/chemistry; Polysaccharides, Bacterial/chemistry; Glucuronic Acid/chemistry
  13. Fulltext Enhancement of mechanical and thermal properties of oil palm empty fruit bunch fiber poly(butylene adipate-co-terephtalate) biocomposites by matrix esterification using succinic anhydride
    Siyamak S, Ibrahim NA, Abdolmohammadi S, Yunus WM, Rahman MZ
    Molecules, 2012 Feb 16;17(2):1969-91.
    PMID: 22343368 DOI: 10.3390/molecules17021969
    In this work, the oil palm empty fruit bunch (EFB) fiber was used as a source of lignocellulosic filler to fabricate a novel type of cost effective biodegradable composite, based on the aliphatic aromatic co-polyester poly(butylene adipate-co-terephtalate) PBAT (Ecoflex™), as a fully biodegradable thermoplastic polymer matrix. The aim of this research was to improve the new biocomposites' performance by chemical modification using succinic anhydride (SAH) as a coupling agent in the presence and absence of dicumyl peroxide (DCP) and benzoyl peroxide (BPO) as initiators. For the composite preparation, several blends were prepared with varying ratios of filler and matrix using the melt blending technique. The composites were prepared at various fiber contents of 10, 20, 30, 40 and 50 (wt %) and characterized. The effects of fiber loading and coupling agent loading on the thermal properties of biodegradable polymer composites were evaluated using thermal gravimetric analysis (TGA). Scanning Electron Microscopy (SEM) was used for morphological studies. The chemical structure of the new biocomposites was also analyzed using the Fourier Transform Infrared (FTIR) spectroscopy technique. The PBAT biocomposite reinforced with 40 (wt %) of EFB fiber showed the best mechanical properties compared to the other PBAT/EFB fiber biocomposites. Biocomposite treatment with 4 (wt %) succinic anhydride (SAH) and 1 (wt %) dicumyl peroxide (DCP) improved both tensile and flexural strength as well as tensile and flexural modulus. The FTIR analyses proved the mechanical test results by presenting the evidence of successful esterification using SAH/DCP in the biocomposites' spectra. The SEM micrograph of the tensile fractured surfaces showed the improvement of fiber-matrix adhesion after using SAH. The TGA results showed that chemical modification using SAH/DCP improved the thermal stability of the PBAT/EFB biocomposite.
    Matched MeSH terms: Benzoyl Peroxide/chemistry; Benzyl Compounds/chemistry; Composite Resins/chemistry*; Fruit/chemistry*; Lignin/chemistry; Plant Oils/chemistry*; Polyesters/chemistry*; Polymers/chemistry*; Succinic Anhydrides/chemistry*
  14. Homology modeling of the human 5-HT1A, 5-HT 2A, D1, and D2 receptors: model refinement with molecular dynamics simulations and docking evaluation
    Yap BK, Buckle MJ, Doughty SW
    J Mol Model, 2012 Aug;18(8):3639-55.
    PMID: 22354276 DOI: 10.1007/s00894-012-1368-5
    5-HT(1A) serotonin and D1 dopamine receptor agonists have been postulated to be able to improve negative and cognitive impairment symptoms of schizophrenia, while partial agonists and antagonists of the D2 and 5-HT(2A) receptors have been reported to be effective in reducing positive symptoms. There is therefore a need for well-defined homology models for the design of more selective antipsychotic agents, since no three-dimensional (3D) crystal structures of these receptors are currently available. In this study, homology models were built based on the high-resolution crystal structure of the β(2)-adrenergic receptor (2RH1) and further refined via molecular dynamics simulations in a 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) lipid bilayer system with the GROMOS96 53A6 united atom force field. Docking evaluations with representative agonists and antagonists using AutoDock 4.2 revealed binding modes in agreement with experimentally determined site-directed mutagenesis data and significant correlations between the computed and experimental pK (i) values. The models are also able to distinguish between antipsychotic agents with different selectivities and binding affinities for the four receptors, as well as to differentiate active compounds from decoys. Hence, these human 5-HT(1A), 5-HT(2A), D1 and D2 receptor homology models are capable of predicting the activities of novel ligands, and can be used as 3D templates for antipsychotic drug design and discovery.
    Matched MeSH terms: Dopamine/chemistry; Serotonin/chemistry; Receptors, Dopamine D1/chemistry*; Receptors, Dopamine D2/chemistry*; Dopamine Antagonists/chemistry; Receptor, Serotonin, 5-HT1A/chemistry*; Receptor, Serotonin, 5-HT2A/chemistry*; Serotonin 5-HT1 Receptor Antagonists/chemistry; Serotonin 5-HT2 Receptor Antagonists/chemistry
  15. Fulltext Effects of nitrogen fertilization on synthesis of primary and secondary metabolites in three varieties of Kacip Fatimah (Labisia pumila Blume)
    Ibrahim MH, Jaafar HZ, Rahmat A, Rahman ZA
    Int J Mol Sci, 2011;12(8):5238-54.
    PMID: 21954355 DOI: 10.3390/ijms12085238
    A split plot 3 by 4 experiment was designed to examine the impact of 15-week variable levels of nitrogen fertilization (0, 90, 180 and 270 kg N/ha) on the characteristics of total flavonoids (TF), total phenolics (TP), total non structurable carbohydrate (TNC), net assimilation rate, leaf chlorophyll content, carbon to nitrogen ratio (C/N), phenyl alanine lyase activity (PAL) and protein content, and their relationships, in three varieties of Labisia pumila Blume (alata, pumila and lanceolata). The treatment effects were solely contributed by nitrogen application; there was neither varietal nor interaction effect observed. As nitrogen levels increased from 0 to 270 kg N/ha, the production of TNC was found to decrease steadily. Production of TF and TP reached their peaks under 0 followed by 90, 180 and 270 kg N/ha treatment. However, net assimilation rate was enhanced as nitrogen fertilization increased from 0 to 270 kg N/ha. The increase in production of TP and TF under low nitrogen levels (0 and 90 kg N/ha) was found to be correlated with enhanced PAL activity. The enhancement in PAL activity was followed by reduction in production of soluble protein under low nitrogen fertilization indicating more availability of amino acid phenyl alanine (phe) under low nitrogen content that stimulate the production of carbon based secondary metabolites (CBSM). The latter was manifested by high C/N ratio in L. pumila plants.
    Matched MeSH terms: Carbohydrates/chemistry; Carbon/chemistry; Chlorophyll/chemistry; Flavonoids/chemistry; Nitrogen/chemistry; Phenols/chemistry; Plant Proteins/chemistry; Plant Leaves/chemistry; Primulaceae/chemistry
  16. Comparison of unmodified and modified BCR sequential extraction schemes for the fractionation of heavy metals in shrimp aquaculture sludge from Selangor, Malaysia
    Nemati K, Abu Bakar NK, Abas MR, Sobhanzadeh E, Low KH
    Environ Monit Assess, 2011 May;176(1-4):313-20.
    PMID: 20632089 DOI: 10.1007/s10661-010-1584-3
    A study was carried out to investigate the fractionation of Cd, Cr, Cu, Fe, Mn, Pb, and Zn in shrimp aquaculture sludge from Selangor, Malaysia, using original (unmodified) and modified four-steps BCR (European Community Bureau of Reference, now known as the Standards Measurements and Testing Program) sequential extraction scheme. Step 2 of the unmodified BCR procedure (subsequently called Method A) involves treatment with 0.1 M hydroxylammonium chloride at pH 2, whereas 0.5 M hydroxylammonium chloride at pH 1.5 was used in the modified BCR procedure (subsequently called Method B). Metal analyses were carried out by flame atomic absorption spectrometry. A pseudo-total aqua-regia digest of BCR CRM 701 has also been undertaken for quality assurance purposes. The recovery of Method A for all metals studied ranges from 96.14% to 105.26%, while the recovery for Method B ranges from 95.94% to 122.40%. Our results reveal that Method A underestimated the proportion of metals bound to the easily reducible fraction except for copper. Therefore, the potential mobility of these elements is higher than others. Thus, to use this sludge as a fertilizer we have to first find a remediation for reduction of heavy metal contamination.
    Matched MeSH terms: Cadmium/chemistry; Chromium/chemistry; Copper/chemistry; Iron/chemistry; Lead/chemistry; Manganese/chemistry; Sewage/chemistry*; Zinc/chemistry; Metals, Heavy/chemistry
  17. Evaluation of load at fracture of Procera AllCeram copings using different luting cements
    Al-Makramani BMA, Razak AAA, Abu-Hassan MI
    J Prosthodont, 2008 Feb;17(2):120-124.
    PMID: 18047490 DOI: 10.1111/j.1532-849X.2007.00270.x
    PURPOSE: The current study investigated the effect of different luting agents on the fracture resistance of Procera AllCeram copings.

    METHODS: Six master dies were duplicated from the prepared maxillary first premolar tooth using nonprecious metal alloy (Wiron 99). Thirty copings (Procera AllCeram) of 0.6-mm thickness were manufactured. Three types of luting media were used: zinc phosphate cement (Elite), glass ionomer cement (Fuji I), and dual-cured composite resin cement (Panavia F). Ten copings were cemented with each type. Two master dies were used for each group, and each of them was used to lute five copings. All groups were cemented according to manufacturer's instructions and received a static load of 5 kg during cementation. After 24 hours of distilled water storage at 37 degrees C, the copings were vertically compressed using a universal testing machine at a crosshead speed of 1 mm/min.

    RESULTS: ANOVA revealed significant differences in the load at fracture among the three groups (p < 0.001). The fracture strength results showed that the mean fracture strength of zinc phosphate cement (Elite), glass ionomer cement (Fuji I), and resin luting cement (Panavia F) were 1091.9 N, 784.8 N, and 1953.5 N, respectively.

    CONCLUSION: Different luting agents have an influence on the fracture resistance of Procera AllCeram copings.

    Matched MeSH terms: Aluminum Oxide/chemistry*; Chromium Alloys/chemistry; Composite Resins/chemistry; Dental Cements/chemistry*; Dental Porcelain/chemistry*; Glass Ionomer Cements/chemistry; Water/chemistry; Zinc Phosphate Cement/chemistry; Resin Cements/chemistry
  18. Stacked films immobilization of MBTH in nafion/sol-gel silicate and horseradish peroxidase in chitosan for the determination of phenolic compounds
    Abdullah J, Ahmad M, Heng LY, Karuppiah N, Sidek H
    Anal Bioanal Chem, 2006 Nov;386(5):1285-92.
    PMID: 17031625
    The stacked-film immobilization of 3-methyl-2-benzothiazolinone hydrazone (MBTH) in hybrid nafion/sol-gel silicate film and horseradish peroxidase (HRP) in chitosan, performed in order to allow the determination of phenolic compounds, was investigated via an optical method. The stacked films were deposited onto a microscope glass slide by a spin-coating technique. The quinone or free radical product formed by the enzymatic reactions of phenolic compounds interacts with MBTH to form azo-dye products, which can be measured spectrophotometrically at a wavelength of 500 nm. The color intensity of the product was found to increase in proportion to the phenolic concentration after 5 min of exposure. The response of the biosensor was linear over concentration ranges of 0.025-0.500, 0.010-0.070 and 0.050-0.300 mM for guaiacol, resorcinol and o-cresol, respectively, and gave detection limits of 0.010, 0.005 and 0.012 mM. The sensor exhibited good sensitivity and stability for at least two months.
    Matched MeSH terms: Azo Compounds/chemistry; Coloring Agents/chemistry; Fluorocarbon Polymers/chemistry*; Horseradish Peroxidase/chemistry*; Hydrazones/chemistry*; Hydrogen Peroxide/chemistry; Silicates/chemistry*; Chitosan/chemistry; Benzothiazoles/chemistry*
  19. Fabrication of composite poly(d,l-lactide)/montmorillonite nanoparticles for controlled delivery of acetaminophen by solvent-displacement method using glass capillary microfluidics
    Othman R, Vladisavljević GT, Thomas NL, Nagy ZK
    Colloids Surf B Biointerfaces, 2016 May 01;141:187-195.
    PMID: 26852102 DOI: 10.1016/j.colsurfb.2016.01.042
    Paracetamol (PCM)-loaded composite nanoparticles (NPs) composed of a biodegradable poly(d,l-lactide) (PLA) polymer matrix filled with organically modified montmorillonite (MMT) nanoparticles were fabricated by antisolvent nanoprecipitation in a microfluidic co-flow glass capillary device. The incorporation of MMT in the polymer improved both the drug encapsulation efficiency and the drug loading, and extended the rate of drug release in simulated intestinal fluid (pH 7.4). The particle size increased on increasing both the drug loading and the concentration of MMT in the polymer matrix, and decreased on increasing the aqueous to organic flow rate ratio. The drug encapsulation efficiency in the NPs was higher at higher aqueous to organic flow rate ratio due to faster formation of the NPs. The PCM-loaded PLA NPs containing 2 wt% MMT in PLA prepared at an aqueous to organic flow rate ratio of 10 with an orifice size of 200 μm exhibited a spherical shape with a mean size of 296 nm, a drug encapsulation efficiency of 38.5% and a drug loading of 5.4%. The encapsulation of MMT and PCM in the NPs was confirmed by transmission electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis and attenuated total reflection-Fourier transform infrared spectroscopy.
    Matched MeSH terms: Acetaminophen/chemistry; Bentonite/chemistry*; Delayed-Action Preparations/chemistry; Drug Carriers/chemistry; Glass/chemistry*; Polyesters/chemistry*; Solvents/chemistry; Analgesics, Non-Narcotic/chemistry; Nanoparticles/chemistry*
  20. Fulltext Formulation and in vitro, in vivo evaluation of effervescent floating sustained-release imatinib mesylate tablet
    Kadivar A, Kamalidehghan B, Javar HA, Davoudi ET, Zaharuddin ND, Sabeti B, et al.
    PLoS One, 2015;10(6):e0126874.
    PMID: 26035710 DOI: 10.1371/journal.pone.0126874
    Imatinib mesylate is an antineoplastic agent which has high absorption in the upper part of the gastrointestinal tract (GIT). Conventional imatinib mesylate (Gleevec) tablets produce rapid and relatively high peak blood levels and requires frequent administration to keep the plasma drug level at an effective range. This might cause side effects, reduced effectiveness and poor therapeutic management. Therefore, floating sustained-release Imatinib tablets were developed to allow the tablets to be released in the upper part of the GIT and overcome the inadequacy of conventional tablets.
    Matched MeSH terms: Imatinib Mesylate/chemistry*; Acrylic Resins/chemistry; Alginates/chemistry; Delayed-Action Preparations/chemistry; Hexuronic Acids/chemistry; Tablets/chemistry*; Sodium Bicarbonate/chemistry; Glucuronic Acid/chemistry; Hypromellose Derivatives/chemistry
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