Displaying publications 1 - 20 of 61 in total

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  1. Xu D, Gao Y, Lin Z, Gao W, Zhang H, Karnowo K, et al.
    Front Chem, 2019;7:943.
    PMID: 32117859 DOI: 10.3389/fchem.2019.00943
    In this study, biochars derived from waste fiberboard biomass were applied in tetracycline (TC) removal in aqueous solution. Biochar samples were prepared by slow pyrolysis at 300, 500, and 800°C, and were characterized by ultimate analysis, Fourier transform infrared (FTIR), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET), etc. The effects of ionic strength (0-1.0 mol/L of NaCl), initial TC concentration (2.5-60 ppm), biochar dosage (1.5-2.5 g/L), and initial pH (2-10) were systemically determined. The results present that biochar prepared at 800°C (BC800) generally possesses the highest aromatization degree and surface area with abundant pyridinic N (N-6) and accordingly shows a better removal efficiency (68.6%) than the other two biochar samples. Adsorption isotherm data were better fitted by the Freundlich model (R2 is 0.94) than the Langmuir model (R2 is 0.85). Thermodynamic study showed that the adsorption process is endothermic and mainly physical in nature with the values of ΔH0 being 48.0 kJ/mol, ΔS0 being 157.1 J/mol/K, and ΔG0 varying from 1.02 to -2.14 kJ/mol. The graphite-like structure in biochar enables the π-π interactions with a ring structure in the TC molecule, which, together with the N-6 acting as electron donor, is the main driving force of the adsorption process.
    Matched MeSH terms: Osmolar Concentration
  2. Samsudin A, Mimiwati Z, Soong T, Fauzi MS, Zabri K
    Eye (Lond), 2010 Jan;24(1):70-3.
    PMID: 19229270 DOI: 10.1038/eye.2009.33
    To study the effect of haemodialysis on intraocular pressure (IOP) of patients at the University Malaya Medical Centre, Kuala Lumpur, and the influence of anterior chamber angles, surgery, and diabetes on the change in IOP after haemodialysis.
    Matched MeSH terms: Osmolar Concentration
  3. Jahan S, Alias YB, Bakar AFBA, Yusoff IB
    Chemosphere, 2019 Feb;217:213-222.
    PMID: 30415119 DOI: 10.1016/j.chemosphere.2018.11.015
    Carbon based materials are emerging as a sustainable alternative to their metal-oxide counterparts. However, their transport behavior under natural aqueous environment is poorly understood. This study investigated the transport and retention profiles of carbon nanoparticles (CNPs) and graphene oxide quantum dots (GOQDs) through column experiments in saturated porous media. CNPs and GOQDs (30 mg/L) were dispersed in natural river water (RW) and passed through the column at a flow rate of 1 mL/min, which mimicking the natural water flow rate. After every 10 min, the column effluents were collected and the mass recovery and retention profiles were monitored. Results indicated that the transport of both carbonaceous colloids was predominantly controlled by surface potential and ionic composition of natural water. The CNPs with its high surface potential (-40 mV) exhibited more column transport and was less susceptible to solution pH (5.6-6.8) variation as compared to GOQDs (-24 mV). The results showed that, monovalent salt (NaCl) was one of the dominating factors for the retention and transport of carbonaceous colloids compared to divalent salt (CaCl2). Furthermore, the presence of natural organic matter (NOM) increased the transport of both carbonaceous colloids and thereby decreases the tendency for column retention.
    Matched MeSH terms: Osmolar Concentration
  4. Hoque MA, Islam MS, Islam MN, Kato T, Nishino N, Ito A, et al.
    Amino Acids, 2014 Oct;46(10):2435-44.
    PMID: 25048030 DOI: 10.1007/s00726-014-1800-5
    Inhibitors of histone deacetylases (HDACs) are a promising class of anticancer agents that have an effect on gene regulation. The naturally occurring cyclic depsipeptide FK228 containing disulfide and Largazole possessing thioester functionalities act as pro-drugs and share the same HDAC inhibition mechanism in cell. Inspired from these facts, we have reported bicyclic tetrapeptide disulfide HDAC inhibitors resembling FK228 with potent activity and enhanced selectivity. In the present study, we report the design and synthesis of several mono and bicyclic tetrapeptide thioester HDAC inhibitors that share the inhibition mechanism similar to Largazole. Most of the compounds showed HDAC1 and HDAC4 inhibition and p21 promoting activity in nanomolar ranges. Among these the monocyclic peptides 1, 2 and bicyclic peptide, 4 are notable demanding more advanced research to be promising anticancer drug candidates.
    Matched MeSH terms: Osmolar Concentration
  5. Subuhi NEAM, Saad SM, Zain NNM, Lim V, Miskam M, Kamaruzaman S, et al.
    J Sep Sci, 2020 Aug;43(16):3294-3303.
    PMID: 32519432 DOI: 10.1002/jssc.201901194
    In this work, a simple, fast, sensitive, and environmentally friendly method was developed for preconcentration and quantitative measurement of bisphenol A in water samples using gas chromatography with mass spectrometry. The preconcentration approach, namely biosorption-based dispersive liquid-liquid microextraction with extractant removal by magnetic nanoparticles was performed based on the formation of microdroplet of rhamnolipid biosurfactant throughout the aqueous samples, which accelerates the mass transfer process between the extraction solvent and sample solution. The process is then followed by the application of magnetic nanoparticles for easy retrieval of the analyte-containing extraction solvent. Several important variables were optimized comprehensively including type of disperser solvent and desorption solvent, rhamnolipid concentration, volume of disperser solvent, amount of magnetic nanoparticles, extraction time, desorption time, ionic strength, and sample pH. Under the optimized microextraction and gas chromatography with mass spectrometry conditions, the method demonstrated good linearity over the range of 0.5-500 µg/L with a coefficient of determination of R2  = 0.9904, low limit of detection (0.15 µg/L) and limit of quantification (0.50 µg/L) of bisphenol A, good analyte recoveries (84-120%) and acceptable relative standard deviation (1.8-14.9%, n = 6). The proposed method was successfully applied to three environmental water samples, and bisphenol A was detected in all samples.
    Matched MeSH terms: Osmolar Concentration
  6. Yakubu R, Peh KK, Tan YT
    Drug Dev Ind Pharm, 2009 Dec;35(12):1430-8.
    PMID: 19929202 DOI: 10.3109/03639040902988566
    The purpose of this study was to design a 24-hour controlled porosity osmotic pump system that utilizes polyvinyl pyrrolidone (PVP) as an osmotic-suspending/release retarding agent of drugs.
    Matched MeSH terms: Osmolar Concentration
  7. Monjezi R, Tey BT, Sieo CC, Tan WS
    PMID: 20538529 DOI: 10.1016/j.jchromb.2010.05.028
    M13 is a non-lytic filamentous bacteriophage (phage). It has been used widely in phage display technology for displaying foreign peptides, and also for studying macromolecule structures and interactions. Traditionally, this phage has been purified by cesium chloride (CsCl) density gradient ultracentrifugation which is highly laborious and time consuming. In the present study, a simple, rapid and efficient method for the purification of M13 based on anion exchange chromatography was established. A pre-packed SepFast Super Q column connected to a fast protein liquid chromatography (FPLC) system was employed to capture released phages in clarified Escherichia coli fermented broth. An average yield of 74% was obtained from a packed bed mode elution using citrate buffer (pH 4), containing 1.5 M NaCl at 1 ml/min flow rate. The purification process was shortened substantially to less than 2 h from 18 h in the conventional ultracentrifugation method. SDS-PAGE revealed that the purity of particles was comparable to that of CsCl gradient density ultracentrifugation method. Plaque forming assay showed that the purified phages were still infectious.
    Matched MeSH terms: Osmolar Concentration
  8. Hassan RA, Heng LY, Tan LL
    Sci Rep, 2019 04 23;9(1):6379.
    PMID: 31015498 DOI: 10.1038/s41598-019-42757-y
    A novel disposable electrochemical biosensor based on immobilized calf thymus double-stranded DNA (dsDNA) on the carbon-based screen-printed electrode (SPE) is developed for rapid biorecognition of carrageenan by using methylene blue (MB) redox indicator. The biosensor protocol for the detection of carrageenan is based on the concept of competitive binding of positively charged MB to the negatively charged dsDNA and carrageenan. The decrement in the MB cathodic peak current (ipc) signal as a result of the released MB from the immobilized dsDNA, and attracted to the carrageenan can be monitored via differential pulse voltammetry (DPV). The biosensor showed high sensitivity and selectivity to carrageenan at low concentration without interference from other polyanions such as alginate, gum arabic and starch. Calibration of the biosensor with carrageenan exhibited an excellent linear dependence from 1-10 mg L-1 (R2 = 0.98) with a detection limit of 0.08 mg L-1. The DNA-based carrageenan biosensor showed satisfactory reproducibility with 5.6-6.9% (n = 3) relative standard deviations (RSD), and possessing several advantages such as simplicity, fast and direct application to real sample analysis without any prior extensive sample treatments, particularly for seaweeds and food analyses.
    Matched MeSH terms: Osmolar Concentration
  9. Tan PY, Tan TB, Chang HW, Tey BT, Chan ES, Lai OM, et al.
    J Agric Food Chem, 2017 Dec 06;65(48):10651-10657.
    PMID: 29124932 DOI: 10.1021/acs.jafc.7b03521
    Considering the health benefits of tocotrienols, continuous works have been done on the encapsulation and delivery of these compounds. In this study, we encapsulated tocotrienols in chitosan-alginate microcapsules and evaluated their release profile. Generally, these tocotrienols microcapsules (TM) displayed high thermal stability. When subjected to pH adjustments (pH 1-9), we observed that the release of tocotrienols was the highest (33.78 ± 0.18%) under basic conditions. The TM were also unstable against the effect of ionic strength, with a high release (70.73 ± 0.04%) of tocotrienols even at a low sodium chloride concentration (50 mM). As for the individual isomers, δ-tocotrienol was the most sensitive to pH and ionic strength. In contrast, β-/γ-tocotrienols were the most ionic-stable isomers but more responsive toward thermal treatment. Simulated gastrointestinal model showed that the chitosan-alginate-based TM could be used to retain tocotrienols in the gastric and subsequently release them in the intestines for possible absorption.
    Matched MeSH terms: Osmolar Concentration
  10. Nadirah Musa, Najiah Musa, Hazza Roshada Ramli, Tajuddin Abd Manaf
    MyJurnal
    Exposure to any type of stressors either environmental, chemical or perceived stressors, results in a series of physiological responses in animals. The purpose of this study was to investigate the effects of thermal stress on physiological responses in red hybrid tilapia. Adult red hybrid tilapia were previously exposed to gradual increment of water temperature in thermoregulated recirculating tanks at a rate of 1oC/8 h from 28 to 31oC and kept for 1, 7 and 14 days. Cortisol, HMG-CoA reductase, total protein and osmolality were determined. Plasma cortisol and HMG-CoA levels were significantly increased in the heat-stressed groups compared to nonstressed groups. Osmolality was also significantly higher (p
    Matched MeSH terms: Osmolar Concentration
  11. Wong FWF, Ariff AB, Stuckey DC
    Crit Rev Biotechnol, 2018 Feb;38(1):31-46.
    PMID: 28427287 DOI: 10.1080/07388551.2017.1312266
    In a conventional protein downstream processing (DSP) scheme, chromatography is the single most expensive step. Despite being highly effective, it often has a low process throughput due to its semibatch nature, sometimes with nonreproducible results and relatively complex process development. Hence, more work is required to develop alternative purification methods that are more cost-effective, but exhibiting nearly comparable performance. In recent years, surfactant precipitation has been heralded as a promising new method for primary protein recovery that meets these criteria and is a simple and cost-effective method that purifies and concentrates. The method requires the direct addition of a surfactant to a complex solution (e.g. a fermentation broth) containing the protein of interest, where the final surfactant concentration is maintained below its critical micelle concentration (CMC) in order to allow for electrostatic and hydrophobic interactions between the surfactant and the target protein. An insoluble (hydrophobic) protein-surfactant complex is formed and backextraction of the target protein from the precipitate into a new aqueous phase is then carried out using either solvent extraction, or addition of a counter-ionic surfactant. Importantly, as highlighted by past researchers, the recovered proteins maintain their activity and structural integrity, as determined by circular dichroism (CD). In this review, various aspects of surfactant precipitation with respect to its general methodology and process mechanism, system parameters influencing performance, protein recovery, process selectivity and process advantages will be highlighted. Moreover, comparisons will be made to reverse micellar extraction, and the current drawbacks/challenges of surfactant precipitation will also be discussed. Finally, promising directions of future work with this separation technique will be highlighted.
    Matched MeSH terms: Osmolar Concentration
  12. Singh HJ
    Jpn. J. Physiol., 1995;45(2):327-36.
    PMID: 7563967
    Standard renal clearance techniques were used to compare the effects of intravenous infusions of L-arginine, D-lysine and glycine on urinary calcium excretion in the rat. A significant calciuric response was evident following the infusion of all three amino acids in all the animals. The maximal effect was evident in rats receiving L-arginine. The mechanism for the increased urinary calcium excretion in rats infused with L-arginine and D-lysine appeared more due to a decreased fractional reabsorption of this cation as no significant changes in the glomerular filtration rate (GFR) were evident in these two groups. The calciuria in rats receiving glycine appears due to increased filtered load secondary to the increased GFR, suggesting that the mechanism for calciuria evident following protein ingestion or amino acid infusion may vary and may be dependent upon the amino acid ingested or infused.
    Matched MeSH terms: Osmolar Concentration
  13. Anis SNS, Mohamad Annuar MS, Simarani K
    Prep Biochem Biotechnol, 2017 Sep 14;47(8):824-834.
    PMID: 28635367 DOI: 10.1080/10826068.2017.1342266
    In vivo and in vitro depolymerizations of intracellular medium-chain-length poly-3-hydroxyalkanoates (mcl-PHA) in Pseudomonas putida Bet001 grown on lauric acid was studied. Both processes were studied under optimum conditions for mcl-PHA depolymerization viz. 0.2 M Tris-HCl buffer, pH 9, ionic strength (I) = 0.2 M at 30°C. For in vitro depolymerization studies, cell-free system was obtained from lysing bacterial cells suspension by ultrasonication at optimum conditions (frequency 37 kHz, 30% of power output, <25°C for 120 min). The comparison between in vivo and in vitro depolymerizations of intracellular mcl-PHA was made. In vitro depolymerization showed lower depolymerization rate but higher yield compared to in vivo depolymerization. The monomer liberation rate reflected the mol% distribution of the initial polymer subunit composition, and the resulting direct individual products of depolymerization were identical for both in vivo and in vitro processes. It points to exo-type reaction for both processes, and potential biological route to chiral molecules.
    Matched MeSH terms: Osmolar Concentration
  14. Musa SH, Basri M, Masoumi HR, Karjiban RA, Malek EA, Basri H, et al.
    Colloids Surf B Biointerfaces, 2013 Dec 1;112:113-9.
    PMID: 23974000 DOI: 10.1016/j.colsurfb.2013.07.043
    Palm kernel oil esters nanoemulsion-loaded with chloramphenicol was optimized using response surface methodology (RSM), a multivariate statistical technique. Effect of independent variables (oil amount, lecithin amount and glycerol amount) toward response variables (particle size, polydispersity index, zeta potential and osmolality) were studied using central composite design (CCD). RSM analysis showed that the experimental data could be fitted into a second-order polynomial model. Chloramphenicol-loaded nanoemulsion was formulated by using high pressure homogenizer. The optimized chloramphenicol-loaded nanoemulsion response values for particle size, PDI, zeta potential and osmolality were 95.33nm, 0.238, -36.91mV, and 200mOsm/kg, respectively. The actual values of the formulated nanoemulsion were in good agreement with the predicted values obtained from RSM. The results showed that the optimized compositions have the potential to be used as a parenteral emulsion to cross blood-brain barrier (BBB) for meningitis treatment.
    Matched MeSH terms: Osmolar Concentration
  15. Hajian R, Mehrayin Z, Mohagheghian M, Zafari M, Hosseini P, Shams N
    Mater Sci Eng C Mater Biol Appl, 2015 Apr;49:769-775.
    PMID: 25687007 DOI: 10.1016/j.msec.2015.01.072
    In this study, an electrochemical sensor was fabricated based on gold nanoparticles/ ethylenediamine/ multi-wall carbon-nanotubes modified gold electrode (AuNPs/en/MWCNTs/AuE) for determination of valrubicin in biological samples. Valrubicin was effectively accumulated on the surface of AuNPs/en/MWCNTs/AuE and produced a pair of redox peaks at around 0.662 and 0.578V (vs. Ag/AgCl) in citrate buffer (pH4.0). The electrochemical parameters including pH, buffer, ionic strength, scan rate and size of AuNPs have been optimized. There was a good linear correlation between cathodic peak current and concentration of valrubicin in the range of 0.5 to 80.0μmolL(-1) with the detection limit of 0.018μmolL(-1) in citrate buffer (pH4.0) and 0.1molL(-1) KCl. Finally, the constructed sensor was successfully applied for determination of valrubicin in human urine and blood serum. In further studies, the different sequences of single stranded DNA probes have been immobilized on the surface of AuNPs decorated on MWCNTs to study the interaction of oligonucleotides with valrubicin.
    Matched MeSH terms: Osmolar Concentration
  16. Esfandyari Bayat A, Junin R, Derahman MN, Samad AA
    Chemosphere, 2015 Sep;134:7-15.
    PMID: 25889359 DOI: 10.1016/j.chemosphere.2015.03.052
    The impact of ionic strength (from 0.003 to 500mM) and salt type (NaCl vs MgCl2) on transport and retention of titanium dioxide (TiO2) nanoparticles (NPs) in saturated limestone porous media was systematically studied. Vertical columns were packed with limestone grains. The NPs were introduced as a pulse suspended in aqueous solutions and breakthrough curves in the column outlet were generated using an ultraviolent-visible spectrometry. Presence of NaCl and MgCl2 in the suspensions were found to have a significant influence on the electrokinetic properties of the NP aggregates and limestone grains. In NaCl and MgCl2 solutions, the deposition rates of the TiO2-NP aggregates were enhanced with the increase in ionic strength, a trend consistent with traditional Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. Furthermore, the NP aggregates retention increased in the porous media with ionic strength. The presence of salts also caused a considerable delay in the NPs breakthrough time. MgCl2 as compared to NaCl was found to be more effective agent for the deposition and retention of TiO2-NPs. The experimental results followed closely the general trends predicted by the filtration and DLVO calculations. Overall, it was found that TiO2-NP mobility in the limestone porous media depends on ionic strength and salt type.
    Matched MeSH terms: Osmolar Concentration
  17. Ullah F, Othman MB, Javed F, Ahmad Z, Akil HM, Rasib SZ
    Int J Biol Macromol, 2016 Feb;83:376-84.
    PMID: 26597568 DOI: 10.1016/j.ijbiomac.2015.11.040
    A new approach to design multifunctional chitosan based nanohydrogel with enhanced glucose sensitivity, stability, drug loading and release profile are reported. Two approaches were followed for functionalization of chitosan based nanohydrogel with 3-APBA via EDC and 3-APTES. The effective functionalization, structure and morphology of Chitosan based IPN respectively were confirmed by FTIR, SEM and AFM. At physiological conditions, the glucose-induced volume phase transition and release profile of the model drug Alizarin Red with 1,2-diol structure (comparative to insulin as a drug as well as a dye for bio separation) were studied at various glucose concentrations, pH and ionic strengths. The results suggested a new concept for diabetes treatment and diols sensitivity in view of their potential hi-tech applications in self-regulated on-off response to the treatment (drug delivery and bio separation concurrently).
    Matched MeSH terms: Osmolar Concentration
  18. Teo SS, Ho CL, Teoh S, Rahim RA, Phang SM
    J Phycol, 2009 Oct;45(5):1093-9.
    PMID: 27032354 DOI: 10.1111/j.1529-8817.2009.00724.x
    Osmotic stress is one of the most significant natural abiotic stresses that occur in the intertidal zones. Seaweeds may physiologically acclimate to changing osmolarity by altering their transcriptome. Here, we investigated the transcriptomic changes of Gracilaria changii (B. M. Xia et I. A. Abbott) I. A. Abbott, J. Zhang et B. M. Xia in response to hyper- and hypoosmotic stresses using a cDNA microarray approach. Microarray analysis revealed that 199 and 200 genes from ∼3,300 genes examined were up- and down-regulated by >2-fold in seaweed samples treated at 50 parts per thousand (ppt) artificial seawater (ASW) compared with those at 30 ppt ASW, respectively. The number of genes that were up- and down-regulated by >2-fold in seaweed samples treated at 10 ppt ASW compared with those at 30 ppt ASW were 154 and 187, respectively. A majority of these genes were only differentially expressed under hyper- or hypoosmotic conditions, whereas 67 transcripts were affected by both stresses. The findings of this study have shed light on the expression profiles of many transcripts during the acclimation of G. changii to hyperosmotic and hypoosmotic conditions. This information may assist in the prioritization of genes to be examined in future studies.
    Matched MeSH terms: Osmolar Concentration
  19. Md Noor J, Hawari R, Mokhtar MF, Yussof SJ, Chew N, Norzan NA, et al.
    Int J Emerg Med, 2020 Feb 07;13(1):6.
    PMID: 32028888 DOI: 10.1186/s12245-020-0264-5
    INTRODUCTION: Methanol poisoning usually occurs in a cluster and initial diagnosis can be challenging. Mortality is high without immediate interventions. This paper describes a methanol poisoning outbreak and difficulties in managing a large number of patients with limited resources.

    METHODOLOGY: A retrospective analysis of a methanol poisoning outbreak in September 2018 was performed, describing patients who presented to a major tertiary referral centre.

    RESULT: A total of 31 patients were received over the period of 9 days. Thirty of them were males with a mean age of 32 years old. They were mostly foreigners. From the 31 patients, 19.3% were dead on arrival, 3.2% died in the emergency department and 38.7% survived and discharged. The overall mortality rate was 61.3%. Out of the 12 patients who survived, two patients had toxic optic neuropathy, and one patient had uveitis. The rest of the survivors did not have any long-term complications. Osmolar gap and lactate had strong correlations with patient's mortality. Serum pH, bicarbonate, lactate, potassium, anion gap, osmolar gap and measured serum osmolarity between the alive and dead patients were significant. Post-mortem findings of the brain were unremarkable.

    CONCLUSION: The mortality rate was higher, and the morbidity includes permanent visual impairment and severe neurological sequelae. Language barrier, severity of illness, late presentation, unavailability of intravenous ethanol and fomipezole and delayed dialysis may have been the contributing factors. Patient was managed based on clinical presentation. Laboratory parameters showed difference in median between group that survived and succumbed for pH, serum bicarbonate, lactate, potassium and osmolar and anion gap. Management of methanol toxicity outbreak in resource-limited area will benefit from a well-designed guideline that is adaptable to the locality.

    Matched MeSH terms: Osmolar Concentration
  20. Seesamut T, Ng B, Sutcharit C, Chanabun R, Panha S
    Sci Rep, 2022 Dec 24;12(1):22304.
    PMID: 36566279 DOI: 10.1038/s41598-022-26099-w
    The cosmopolitan littoral earthworm Pontodrilus litoralis is distributed in tropical and sub-tropical coastal habitats, whereas P. longissimus is reported only in the Thai-Malay coastal line. In the present study, we examined the difference in salinity effect on the survival rate, wet weight (hereafter weight) change, behaviour, and osmolality of these two Pontodrilus species. A 28 d exposure to varying salinity concentration (0-50 ppt) revealed that P. litoralis is able to survive over a wide salinity range than P. longissimus, with the latter species exhibiting a low survival rate over the same salinity range. During short-term exposure (0-96 h) to a salinity of less than 30 ppt, P. litoralis exhibited weight gain and this was significant in the first 12 h of exposure. However, P. longissimus gained weight when exposed to salinity at under 10 ppt in the first 72 h of exposure. The two species of Pontodrilus behaved differently when exposed to different salinities. The coelomic fluid osmolarity of Pontodrilus was related to the exposure medium and was mostly maintained as hyperosmotic to the external medium over the range of salinities tested. This study shows how two different species of the littoral earthworm genus Pontodrilus respond to a change in salinity, which may explain their dispersal pattern and shape their distribution pattern throughout Southeast Asia.
    Matched MeSH terms: Osmolar Concentration
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