Displaying publications 1 - 20 of 47 in total

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  1. Voltammetric determination of iodide in iodized table salt using cetyltrimethylammonium bromide as ion-pairing
    Jamilan MA, Abdullah J, Alang Ahmad SA, Md Noh MF
    J Food Sci Technol, 2019 Aug;56(8):3846-3853.
    PMID: 31413410 DOI: 10.1007/s13197-019-03855-x
    In this work, voltammetric study based on cetyltrimethylammonium bromide (CTAB) as an ion-pairing agent for the determination of iodine level in iodized table salt has been explored. CTAB was used as an intermediate compound between iodide (I-) and the electrode due to its ability to dissociate to produce cetyltrimethylammonium ions ([CTA]+). The [CTA]+ with a long hydrophobic alkyl chain can be directly adsorbed onto the surface of the working electrode, and this in turns coated the electrode with cationic charge and enhance the electrode ability to bind to iodide (I-) and other molecular iodine ions. A mixture of iodide and CTAB ([CTA]+I-) was prepared and potential of 1.0 V for 60.0 s was applied to pre-concentrate the solution on the working electrode causing the [CTA]+I- to oxidize to iodine (I2). The produced I2 immediately react with chloride ion (Cl-) from the electrolyte of hydrochloric acid (HCl) to produce I2Cl- and form ion-pair with CTA+ as [CTA]+I2Cl-. The linear calibration curve of the developed method towards iodide was in the concentration range of 0.5-4.0 mg/L with sensitivity of - 1.383 µA mg/L-1 cm-2 (R2 = 0.9950), limit of detection (LOD) of 0.3 mg/L and limit of quantification (LOQ) of 1.0 mg/L, respectively. The proposed method indicates good agreement with the standard method for iodine determination with recovery range from 95.0 to 104.3%. The developed method provided potential application as a portable on-site iodine detector.
    Matched MeSH terms: Hydrochloric Acid
  2. Verifying measurements of residual calcium content in demineralised cortical bone
    Ariffin AF, Yusof N, Mohd S, Rahman SA, Ramalingam S, Mansor A, et al.
    Cell Tissue Bank, 2019 Dec;20(4):527-534.
    PMID: 31456097 DOI: 10.1007/s10561-019-09785-4
    Calcium contents of demineralised human cortical bone determined by titrimetric assay and atomic absorption spectrophotometry technique were verified by comparing to neutron activation analysis which has high recovery of more than 90%. Conversion factors determined from the comparison is necessary to correct the calcium content for each technique. Femurs from cadaveric donors were cut into cortical rings and demineralised in 0.5 M hydrochloric acid for varying immersion times. Initial calcium content in the cortical bone measured by titration was 4.57%, only 21% of the measurement by neutron activation analysis; while measured by atomic absorption spectrophotometer was 13.4%, only 61% of neutron activation analysis. By comparing more readings with the measurements by neutron activation analysis with 93% recovery, a conversion factor of 4.83 was verified and applied for the readings by titration and 1.45 for atomic absorption spectrophotometer in calculating the correct calcium contents. The residual calcium content started to reduce after the cortical bone was demineralised in hydrochloric acid for 8 h and reduced to 13% after 24 h. Using the linear relationship, the residual calcium content could be reduced to less than 8% after immersion in hydrochloric acid for 40 h. Atomic absorption spectrophotometry technique is the method of choice for calcium content determination as it is more reliable compared to titrimetric assay.
    Matched MeSH terms: Hydrochloric Acid/chemistry
  3. Utilization of red mud waste into mesoporous ZSM-5 for methylene blue adsorption-desorption studies
    Tehubijuluw H, Subagyo R, Yulita MF, Nugraha RE, Kusumawati Y, Bahruji H, et al.
    Environ Sci Pollut Res Int, 2021 Mar 13.
    PMID: 33712959 DOI: 10.1007/s11356-021-13285-y
    Red mud as industrial waste from bauxite was utilized as a precursor for the synthesis of mesoporous ZSM-5. A high concentration of iron oxide in red mud was successfully removed using alkali fusion treatment. Mesoporous ZSM-5 was synthesized using cetyltrimethylammonium bromide (CTABr) as a template via dual-hydrothermal method, and the effect of crystallization time was investigated towards the formation of mesopores. Characterization using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), N2 adsorption-desorption, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) indicated the formation of cubic crystallite ZSM-5 with high surface area and mesopore volume within 6 h of crystallization. Increasing the crystallization time revealed the evolution of highly crystalline ZSM-5; however, the surface area and mesoporosity were significantly reduced. The effect of mesoporosity was investigated on the adsorption of methylene blue (MB). Kinetic and thermodynamic analysis of MB adsorption on mesoporous ZSM-5 was carried out at a variation of adsorption parameters such as the concentration of MB solution, the temperatures of solution, and the amount of adsorbent. Finally, methanol, 1-butanol, acetone, hydrochloric acid (HCl), and acetonitrile were used as desorbing agents to investigate the reusability and stability of mesoporous ZSM-5 as an adsorbent for MB removal.
    Matched MeSH terms: Hydrochloric Acid
  4. Ultrasound mediated acid hydrolysis of konjac glucomannan
    Cheng, L.H., Nur Halawiah, H., Lai, B.N, Yong, H.M., Ang, S.L.
    International Food Research Journal, 2010;17(4):1043-1050.
    MyJurnal
    Konjac glucomannan (KGM) was treated with or without sonication and/or hydrochloric acid (HCl).
    Hydrolysis effects on KGM were studied for properties such as degree of hydrolysis, fluidity, molecular mass, and creep properties. The degree of hydrolysis for sonicated KGM and acid treated KGM were not significantly different. However, the combination treatment of acid hydrolysis and sonication was found effective in yielding a smaller molecular weight fraction of KGM and solution with higher fluidity. From the creep analysis, KGM treated with combination treatment exhibited the highest compliance among samples tested. In general, ultrasound mediated acid hydrolysis was found to be a promising technique in degrading high molecular weight biopolymer. This could be attributed to a localized high temperature and high shear forces generated during cavitation that facilitated the endothermic acid hydrolysis.
    Matched MeSH terms: Hydrochloric Acid
  5. Fulltext THE EFFECT OF LOW pH LEVEL ON ZEBRAFISH (Danio rerio) REPRODUCTIVE PERFORMANCE
    Ikram Ismail, Siti-Ariza Aripin
    UMT Journal of Undergraduate Research, 2020;2(1):15-20.
    MyJurnal
    Danio rerio or commonly known as zebrafish are a very popular fish among scientists and also a well-known vertebrate model species widely used in research. Zebrafish, are also a popular species among aquarists and have been put in aquariums all around the world as ornamental fish. The acid rain phenomenon has lowered the pH level of the wild habitat of zebrafish by shifting it to a more acidic pH level. This study was carried out to observe the effect of low pH level on the reproductive performance of zebrafish. The zebrafish were quarantined for a week to make sure they were healthy to be used in the experiment. The zebrafish were reared continuously for 14 days in three different pH treatments T1 (pH 2-4), T2 (pH 4-6), T3 (pH 6-8)). T3 (pH 6-8) was used as the control treatment. Hydrochloric acid (HCl) was used to control the pH level of treatments T1 (pH 2-4), T2 (pH 4-6), T3 (pH 6-8) with three replicates of each treatment. The male chasing female frequency was significant (p: 0.0001) and the data showed the highest frequency (2568.000±140.6272) at treatment 3 (pH 6-8). For the spawning frequency of zebrafish, treatment 3 (pH 6-8) showed the highest value (4.000±0.5774) followed by treatment 2 and treatment 1 and the data was significant (p: 0.0004). The fertilisation rate of the zebrafish was significant (p: 0.0001) and the highest was shown at T2 (pH 4-6) with 89.8018±0.3782, followed by T3 and treatment T1. For the hatching rate of the zebrafish, the data collected were significant (p: 0.0002) and the highest value of 2.9350±0.4070 was shown at T3 (pH 6-8), followed by T2 (pH 4-6) and T1 (pH 2-4). The overall result showed that pH 2-4 had the worst effect on the reproductive performance of zebrafish. Therefore, low pH has a significant effect on reducing the reproductive performance of zebrafish. The local fish population can be affected by the decrease of pH level due to acid rains and chemical waste pollution.
    Matched MeSH terms: Hydrochloric Acid
  6. Fulltext Synthesis, characterizations and anti-corrosion screening of Sadimine and Brosadamine
    Siti Noriah Mohd Shotor, Nur Anis Atirah Zulkiflee
    Journal of Academia Universiti Teknologi MARA Negeri Sembilan, 2020;8(2):1-8.
    MyJurnal
    This paper deals with a review of the inhibition activity of a Schiff bases on the deterioration of mild steel in hydrochloric acid media. Two Schiff base ligands namely N,N’- Bis(salicylidene) ethylenediamine (Sadimine) and N,N’-Bis(bromosalicylidene)- ethylenediamine (Brosadimine) were synthesized from the condensation reactions of salicylaldehyde or 5-bromosalicylaldehyde with ethylenediamine respectively and evaluated as corrosion inhibitor for mild steel in 1 M HCl solution using weight loss method. The use of inhibitors is one of the most practical methods for protection of mild steel against corrosion in acidic media. Schiff bases are widely being employed in such applications. This paper highlights the influence of structure–inhibition activity relationship of Schiff base compounds
    on their performance as corrosion inhibitors of mild steel in acid media. Sadimine and
    Brosadimine show appreciable corrosion inhibition efficiency against the corrosion of mild
    steel in 1 M HCl solution at room temperature. It has been found that Brosadimine shows
    greater corrosion inhibition efficiency than Sadimine due to extra halogen group presence in
    the structure. As the concentration of studied inhibitors increases, the corrosion inhibition
    efficiency of the prepared compounds also increases. This study demonstrated that corrosion
    inhibitors for metals and alloys can preserve the quality and life of metals from corrosion.
    Matched MeSH terms: Hydrochloric Acid
  7. Syk/NF-κB-targeted anti-inflammatory activity of Melicope accedens (Blume) T.G. Hartley methanol extract
    Kim JK, Choi E, Hong YH, Kim H, Jang YJ, Lee JS, et al.
    J Ethnopharmacol, 2021 May 10;271:113887.
    PMID: 33539951 DOI: 10.1016/j.jep.2021.113887
    ETHNOPHARMACOLOGICAL RELEVANCE: Melicope accedens (Blume) Thomas G. Hartley is a plant included in the family Rutaceae and genus Melicope. It is a native plant from Vietnam that has been used for ethnopharmacology. In Indonesia and Malaysia, the leaves of M. accedens are applied externally to decrease fever.

    AIM OF THE STUDY: The molecular mechanisms of the anti-inflammatory properties of M. accedens are not yet understood. Therefore, we examined those mechanisms using a methanol extract of M. accedens (Ma-ME) and determined the target molecule in macrophages.

    MATERIALS AND METHODS: We evaluated the anti-inflammatory effects of Ma-ME in lipopolysaccharide (LPS)-stimulated RAW264.7 cells and in an HCl/EtOH-triggered gastritis model in mice. To investigate the anti-inflammatory activity, we performed a nitric oxide (NO) production assay and ELISA assay for prostaglandin E2 (PGE2). RT-PCR, luciferase gene reporter assays, western blotting analyses, and a cellular thermal shift assay (CETSA) were conducted to identify the mechanism and target molecule of Ma-ME. The phytochemical composition of Ma-ME was analyzed by HPLC and LC-MS/MS.

    RESULTS: Ma-ME suppressed the production of NO and PGE2 and the mRNA expression of proinflammatory genes (iNOS, IL-1β, and COX-2) in LPS-stimulated RAW264.7 cells without cytotoxicity. Ma-ME inhibited NF-κB activation by suppressing signaling molecules such as IκBα, Akt, Src, and Syk. Moreover, the CETSA assay revealed that Ma-ME binds to Syk, the most upstream molecule in the NF-κB signal pathway. Oral administration of Ma-ME not only alleviated inflammatory lesions, but also reduced the gene expression of IL-1β and p-Syk in mice with HCl/EtOH-induced gastritis. HPLC and LC-MS/MS analyses confirmed that Ma-ME contains various anti-inflammatory flavonoids, including quercetin, daidzein, and nevadensin.

    CONCLUSIONS: Ma-ME exhibited anti-inflammatory activities in vitro and in vivo by targeting Syk in the NF-κB signaling pathway. Therefore, we propose that Ma-ME could be used to treat inflammatory diseases such as gastritis.

    Matched MeSH terms: Hydrochloric Acid/toxicity
  8. Fulltext Survivability of Acanthamoeba strains isolated from clinical and environmental specimens during axenization
    Nurul Farhana Jufri, Anisah Nordin, Mohamed Kamel Abd Ghani, Yusof Suboh, Noraina Abd Rahim
    Jurnal Sains Kesihatan Malaysia, 2011;9(1):1-3.
    MyJurnal
    Acanthamoeba is a free living protozoa that can cause keratitis and granulomatous amoebic encephalitis. Physiological characteristics of this amoeba are found to have a medical importance in which it can be related to the pathogenicity potential of the organism. This study was carried out to investigate the physiological characteristics of survivability during axenization. Six Acanthamoeba strains from three clinical isolates (HSB 1, HKL 48 and HKL 95) and three environmental isolates (PHS 2, PHS 11 and PHS 15) were used in this study. Axenization test was done by treating cysts with hydrochloric acid (3%) and Page saline containing Gentamicin (100 µg/ml). Cysts were then cultured into PYG enrich media, incubated at 30oC and the presence and proliferation of trophozoites of Acanthamoeba were observed. This study showed that PHS 15, HSB 1, HKL 48 and HKL 95 could be axenized but they have poor proliferation rate in PYG enrich media. The result showed that the difference between both clinical and environmental isolates was observed in two strains; PHS 2 and PHS 11. This indicates that there is a possibility that the physiological traits of strains from both isolates are the same and strains from the environment are able to show the pathogenic potential and capable of causing infection to human.
    Matched MeSH terms: Hydrochloric Acid
  9. Fulltext SYNTHESIS, CHARACTERISATION AND CORROSION INHIBITION SCREENING: Cu[EtBenzdtc]2 AND Cu[BuMedtc]2
    Nur Alia Atiqah Alias, Nabilah Syakirah Zolkifli, Mimi Wahidah Mohd Radzi, Nur Nadia Dzulkifli
    Journal of Academia Universiti Teknologi MARA Negeri Sembilan, 2021;9(1):56-65.
    MyJurnal
    Mild steel plays an essential part in many construction industries due to its low cost and excellent mechanical properties. However, the use of strong acid in pickling, construction, and oil refining processes adds to a serious corrosion problem for mild steel. Two Cu(II) dithiocarbamate (DTC) complexes were successfully synthesised, namely Cu(II) ethyl-benzyl DTC (Cu[EtBenzdtc]2) and Cu(II) butyl-methyl DTC (Cu[BuMedtc]2) complexes, by a condensation reaction and subsequently used to scrutinise the corrosion resistance activity towards mild steel in acidic media. The proposed structures of complexes were characterised by using the Fourier transform infrared (FTIR) and ultraviolet-visible (UV-Vis) spectroscopies. The melting point for Cu[EtBenzdtc]2 was found around 362–375°C, and 389–392°C for Cu[BuMedtc]2. The percentages of Cu(II) found in Cu[EtBenzdtc]2 and Cu[BuMedtc]2 were 7.6% and 7.5%, respectively. Both complexes were non-electrolyte based on the molar conductivity analysis. Their corrosion inhibition performances were tested by using a weight loss measurement. Cu[BuMedtc]2 showed a good result as a corrosion inhibitor compared to Cu[EtBenzdtc]2. The complexes showed good effectiveness in sulfuric acid (H2SO4) compared to hydrochloric acid (HCl) solution. Furthermore, Cu[BuMedtc]2 showed a good result as a corrosion inhibitor compared to Cu[EtBenzdtc]2 with the highest percentage of corrosion inhibition recorded at 91.8%. Meanwhile, the highest percentage of corrosion inhibition shown by Cu[EtBenzdtc]2 was only 86.9%. The lowest corrosion rate shown for Cu[BuMedtc]2 was 8.1944×10-4 cm-1 h-1. Meanwhile, the Cu[EtBenzdtc]2 showed the lowest corrosion rate only at 1.3194×10-3 cm-1 h-1. This implies that Cu[BuMedtc]2 showed lower corrosion rate but higher inhibition efficiency compared to Cu[EtBenzdtc]2.
    Matched MeSH terms: Hydrochloric Acid
  10. Restoration of engraved marks on steel surfaces by etching technique
    Zaili MA, Kuppuswamy R, Harun H
    Forensic Sci Int, 2007 Aug 24;171(1):27-32.
    PMID: 17088038
    It is known that restoration of erased engraved identification marks on the engine and the chassis of a car or on a firearm has low success rate. Unlike stamping, engraving on a metal surface leaves no pronounced, permanent subsurface deformation in the crystalline structure, also called dislocation that can be revealed by suitable methods. Hence, the current research work investigated whether metallographic reagents used in the restoration of stamp (compression) marks could be applied to recover engraved marks on steel surfaces and also to establish the sensitivity and effectiveness of some of these reagents for the restoration of the marks. Experiments were conducted by mechanically engraving alphanumeric characters on several steel plates using a computer controlled engraving machine called Gravograph. The markings were later erased from the above steel plates by removing the metal in stages of 0.01 mm through 0.04 mm below the bottom of the engraving. Several plates were thus prepared wherein each one had been abraded to a specific depth. Then eight metallographic reagents were tested on each one of the above erased plates using a swabbing technique. The results had shown that while most of the reagents were able to restore marks up to certain levels of erasure, the reagent 5 g copper sulphate, 60 ml water, 30 ml concentrated ammonium hydroxide and 60 ml concentrated hydrochloric acid restored marks erased to a depth of 0.04 mm below the engraving depth, thus presenting itself the most sensitive reagent. Quite significantly, the above reagent was also able to decipher successfully the original engraved marks that had been erased and engraved with a new number, or obliterated by centre punching. The results of this research work should benefit the forensic practitioners engaged in the serial number recovery on vehicles, firearms and other objects.
    Matched MeSH terms: Hydrochloric Acid
  11. Relative bioavailability of the hydrochloride, sulphate and ethyl carbonate salts of quinine
    Jamaludin A, Mohamad M, Navaratnam V, Selliah K, Tan SC, Wernsdorfer WH, et al.
    Br J Clin Pharmacol, 1988 Feb;25(2):261-3.
    PMID: 3358888
    The hydrochloride, sulphate and ethylcarbonate salts of quinine were given in single oral doses (600 mg base equivalent) to nine healthy male subjects according to a cross-over design. No statistically significant differences were noted in the plasma drug concentration-time profiles although inter- and intra-subject variation in AUC, Cmax and tmax values was appreciable. The ethylcarbonate salt may be preferred for use in paediatric patients because of its neutral taste.
    Matched MeSH terms: Hydrochloric Acid
  12. Reduction of mercury from mackerel fillet using combined solution of cysteine, EDTA, and sodium chloride
    Hajeb P, Jinap S
    J Agric Food Chem, 2012 Jun 13;60(23):6069-76.
    PMID: 22515475 DOI: 10.1021/jf300582j
    An acidic solution containing mercury chelating agents to eliminate mercury in raw fish (mackerel) fillet was developed. The solution contained hydrochloric acid, sodium hydroxide, cysteine, EDTA, and NaCl. The optimum conditions for mercury reduction were achieved using response surface methodology (RSM) at cysteine concentration of 1.25%, EDTA of 275 mg/L, NaCl of 0.5%, pH of 3.75, and exposure time of 18 min. The optimized conditions produced a solution which can remove up to 91% mercury from raw fish fillet. Cysteine and EDTA were identified as potential chelating agents with the greatest potential for use. The solution can be employed in fish industries to reduce mercury in highly contaminated fish.
    Matched MeSH terms: Hydrochloric Acid/chemistry
  13. Recovering obliterated engraved marks on aluminium surfaces by etching technique
    Baharum MI, Kuppuswamy R, Rahman AA
    Forensic Sci Int, 2008 May 20;177(2-3):221-7.
    PMID: 18313246 DOI: 10.1016/j.forsciint.2008.01.004
    A study has been made of the characteristics of restoration of obliterated engraved marks on aluminium surfaces by etching technique. By etching different reagents on 0.61mm thick sheets of aluminium (99wt%) on which some engraved marks had been erased to different depths it was found that the reagent 60% hydrochloric acid and 40% sodium hydroxide on alternate swabbing on the surfaces was found to be the most sensitive one for these metal surfaces. This reagent was able to restore marks in the above plates erased down to 0.04mm below the bottom of the engraving. The marks also presented excellent contrast with the background. This reagent was further experimented with similar aluminium surfaces, but of relatively greater thickness of 1.5mm. It was noticed that the recovery depth increased slightly to 0.06mm; this suggested the dependence of recovery depth on the thickness of the sheet metal. Further, the depth of restoration decreased in cases where the original number was erased and over which a new number was engraved; the latter results are similar to those of steel surfaces reported earlier [M.A.M. Zaili, R. Kuppuswamy, H. Harun, Restoration of engraved marks on steel surfaces by etching technique, Forensic Sci. Int. 171 (2007) 27-32].
    Matched MeSH terms: Hydrochloric Acid
  14. Fulltext Purification of metallurgical grade silicon by acid leaching
    Lashgari, V.A., Yoozbashizadeh, H.
    ASM Science Journal, 2007;1(1):37-41.
    MyJurnal
    Silicon, as the most important electronic material, has a lot of applications in the electronic industry and this includes the use of silicon in solar cells. One of the solar grade silicon production processes is the use of acid leaching for the removal of metallic impurities from silicon. The main advantage of this process for silicon purification is that it is based on a low temperature process. The purification of metallurgical grade silicon by acid leaching was studied as a function of time, temperature and etching. Based upon experimental results and under optimum conditions, it was possible to remove 41%, 71% and 25% of iron, calcium and aluminum respectively, with the use of aqua regia.
    Matched MeSH terms: Hydrochloric Acid
  15. Process development for the production of protein hydrolysate from cockle (Anadara granosa) meat wash water
    Haslaniza H, Maskat M, Wan Aida W, Mamot S
    Sains Malaysiana, 2014;43:53-63.
    A study was carried out to determine the process parameters and optimization for the hydrolysis of protein precipitate from cockle (Anadara granosa) meat wash water. Precipitation of the protein in the wash water was done using pH manipulation (pH3-8). The precipitate was hydrolyzed using hydrochloric acid (HCl) and optimized for HCl volume, HCl concentration and hydrolysis time using response surface methodology (RSM) based on a central composite rotatable design. Based on the results, hydrolysis of cockle meat wash water precipitate was carried out by precipitation of the wash water at pH4. Optimum condition for the hydrolysis of 2.0 g of cockle meat wash water precipitate was 25 mL of 1 N HCl for 10 h which resulted in nitrogen content (NC) of 0.7% and degree of hydrolysis (DH) of 55%. NC and DH were significantly influenced only by the hydrolysis time.
    Matched MeSH terms: Hydrochloric Acid
  16. Fulltext Preparation and evaluation of water-in-soybean oil-in-water emulsions by repeated premix membrane emulsification method using cellulose acetate membrane
    Muhamad II, Quin CH, Selvakumaran S
    J Food Sci Technol, 2016 Apr;53(4):1845-55.
    PMID: 27413211 DOI: 10.1007/s13197-015-2107-6
    The purpose of this study was to investigate the preparation of formulated water- in-soybean oil-in-water emulsions by repeated premix membrane emulsification method using a cellulose acetate membrane. The effect of selective membrane emulsification process parameters (concentration of the emulsifiers, number of passes of the emulsions through the membrane and storage temperature) on the properties and stability of the developed emulsions were also investigated. 1, 3, 6, 8-pyrenetetrasulfonic acid tetrasodium salt (PTSA) was used as a hydrophilic model ingredient for the encapsulation of bioactive substances. W/O emulsions with 7 wt% (weight percentage) PGPR displays homogeneous and very fine dispersions, with the median diameter at 0.640 μm. Meanwhile, emulsions prepared by membrane emulsification (fine W/O/W) showed the highest stability at Tween 80 concentrations of 0.5 wt.% (weight percentage). It concluded that at 7 wt.% (weight percentage) PGPR concentration and 0.5 wt.% (weight percentage) Tween 80 concentrations, the most uniform particles with minimum mean size of oil drops (9.926 μm) were obtained after four passes through the membrane. Thus, cellulose acetate membrane can be used for preparing a stable W/O/W emulsions by repeated premix ME due to low cost and relatively easy to handle.
    Matched MeSH terms: Hydrochloric Acid
  17. Optimization of cell disruption methods for efficient recovery of bioactive metabolites via NMR of three freshwater microalgae (chlorophyta)
    Ma NL, Teh KY, Lam SS, Kaben AM, Cha TS
    Bioresour Technol, 2015 Aug;190:536-42.
    PMID: 25812996 DOI: 10.1016/j.biortech.2015.03.036
    This study demonstrates the use of NMR techniques coupled with chemometric analysis as a high throughput data mining method to identify and examine the efficiency of different disruption techniques tested on microalgae (Chlorella variabilis, Scenedesmus regularis and Ankistrodesmus gracilis). The yield and chemical diversity from the disruptions together with the effects of pre-oven and pre-freeze drying prior to disruption techniques were discussed. HCl extraction showed the highest recovery of oil compounds from the disrupted microalgae (up to 90%). In contrast, NMR analysis showed the highest intensity of bioactive metabolites obtained for homogenized extracts pre-treated with freeze-drying, indicating that homogenizing is a more favorable approach to recover bioactive substances from the disrupted microalgae. The results show the potential of NMR as a useful metabolic fingerprinting tool for assessing compound diversity in complex microalgae extracts.
    Matched MeSH terms: Hydrochloric Acid/chemistry*
  18. On the sensitivity of some common metallographic reagents to restoring obliterated marks on medium carbon (0.31% C) steel surfaces
    Yin SH, Kuppuswamy R
    Forensic Sci Int, 2009 Jan 10;183(1-3):50-3.
    PMID: 19041202 DOI: 10.1016/j.forsciint.2008.10.009
    Chemical etching, which is the most sensitive method to recover obliterated serial numbers on metal surfaces, has been practised quite successfully in forensic science laboratories all over the world. A large number of etchants suitable for particular metal surfaces based on empirical studies is available in the literature. This article reviews the sensitivity and efficacy of some popular etchants for recovering obliterated marks on medium carbon steel (0.31% C with ferrite-pearlite microstructure) used in automobile parts. The experiments involved engraving these carbon steel plates with some alphanumeric characters using a computer controlled machine "Gravograph" and erasing them to several depths below the bottom of their engraving depth. Seven metallographic reagents of which most of them were copper containing compounds were chosen for etching. The erased plates were etched with every one of these etchants using swabbing method. The results have revealed that Fry's reagent comprising cupric chloride 90 g, hydrochloric acid 120 mL and water 100mL provided the necessary contrast and was concluded to be the most sensitive. The same reagent was recommended by earlier workers for revealing strain lines in steel surfaces. Earlier, another reagent containing 5 g copper sulphate, 60 mL water, 30 mL (conc.) ammonium hydroxide, and 60 mL (conc.) hydrochloric acid was proved to be more sensitive to restore erased marks on low carbon steel (0.1% C with ferrite-pearlite structure) [M.A.M. Zaili, R. Kuppuswamy, H. Harun, Restoration of engraved marks on steel surfaces by etching technique, Forensic Sci. Int. 171 (2007) 27-32]. Thus the sensitivity of the etching reagent on steel surfaces appeared to be dependent on the content of carbon in the steel.
    Matched MeSH terms: Hydrochloric Acid
  19. Non-erosive reflux disease (NERD), symptomatic and asymptomatic erosive reflux disease (ERD): from hypersensitive to hyposensitive esophagus
    Hartono JL, Qua CS, Goh KL
    Dig Dis Sci, 2011 Jan;56(1):90-6.
    PMID: 20467897 DOI: 10.1007/s10620-010-1275-5
    AIMS: To compare the esophageal sensitivity to acid and saline in patients with symptomatic and asymptomatic erosive reflux disease (ERD), non-erosive reflux disease (NERD) and controls, and to assess the response to proton-pump inhibitors in patients with symptomatic ERD and NERD.

    METHODOLOGY: Patients with GERD and a control group of healthy asymptomatic volunteers were recruited. All subjects underwent esophagogastroduodenoscopy and the acid-saline perfusion test. Symptomatic ERD and NERD patients were given rabeprazole 20 mg twice daily for 2 weeks and their response to treatment assessed.

    RESULTS: A total of 105 subjects were recruited: ERD=37 (symptomatic=24, asymptomatic=13), NERD=34 and controls=34. During saline perfusion, only the NERD group recorded a significantly higher sensitivity score compared to controls (2.74±7.28 vs. 0) (p=0.035). During acid perfusion, symptomatic ERD (15.42±13.42) and NERD (16.71±15.04) had significantly higher scores versus controls and asymptomatic ERD patients (both p<0.001). The mean %∆ reflux symptom score following treatment was significantly higher in symptomatic ERD patients compared to NERD patients (89.08±21.67 vs. 58.53±32.54; p<0.001).

    CONCLUSIONS: Patients with NERD were a generally hypersensitive group while asymptomatic ERD patients represent a hyposensitive group of patients which merits further study.

    Matched MeSH terms: Hydrochloric Acid/adverse effects
  20. New One-Pot Synthesis of 1,3,5-Triazines: Three-Component Condensation, Dimroth Rearrangement, and Dehydrogenative Aromatization
    Junaid A, Lim FPL, Tiekink ERT, Dolzhenko AV
    ACS Comb Sci, 2019 07 08;21(7):548-555.
    PMID: 31180634 DOI: 10.1021/acscombsci.9b00079
    A new, effective one-pot synthesis of the 6, N2-diaryl-1,3,5-triazine-2,4-diamines under microwave irradiation was developed. The method involved an initial three-component condensation of cyanoguanidine, aromatic aldehydes, and arylamines in the presence of hydrochloric acid. Without isolation, the resulting 1,6-diaryl-1,6-dihydro-1,3,5-triazine-2,4-diamines were treated with a base to initiate Dimroth rearrangement and spontaneous dehydrogenative aromatization, affording the desired compounds. The developed method was found to be sufficiently general in scope, tolerating various aromatic aldehydes and amines; by using their combinations in the first step, a representative library of 110 compounds was successfully prepared and screened for anticancer properties.
    Matched MeSH terms: Hydrochloric Acid/pharmacology*; Hydrochloric Acid/chemistry
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