Displaying publications 1 - 20 of 1018 in total

  1. Chidan Kumar CS, Panicker CY, Fun HK, Mary YS, Harikumar B, Chandraju S, et al.
    PMID: 24607470 DOI: 10.1016/j.saa.2014.01.145
    2-(4-Chlorophenyl)-2-oxoethyl 3-nitrobenzoate is synthesized by reacting 4-chlorophenacyl bromide with 3-nitrobenzoic acid using a slight excess of potassium or sodium carbonate in DMF medium at room temperature. The structure of the compound was confirmed by IR and single-crystal X-ray diffraction studies. FT-IR spectrum of 2-(4-chlorophenyl)-2-oxoethyl 3-nitrobenzoate was recorded and analyzed. The crystal structure is also described. The vibrational wavenumbers were computed using HF and DFT methods and are assigned with the help of potential energy distribution method. The first hyperpolarizability and infrared intensities are also reported. The geometrical parameters of the title compound obtained from XRD studies are in agreement with the calculated (DFT) values. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. The HOMO and LUMO analysis are used to determine the charge transfer within the molecule. MEP was performed by the DFT method.
    Matched MeSH terms: Spectroscopy, Fourier Transform Infrared*
  2. Rohman A, Man YB, Riyanto S
    Phytochem Anal, 2011 Sep-Oct;22(5):462-7.
    PMID: 22033916 DOI: 10.1002/pca.1304
    Red fruit (Pandanus conoideus Lam) is endemic plant of Papua, Indonesia and Papua New Guinea. The price of its oil (red fruit oil, RFO) is 10-15 times higher than that of common vegetable oils; consequently, RFO is subjected to adulteration with lower price oils. Among common vegetable oils, canola oil (CaO) and rice bran oil (RBO) have similar fatty acid profiles to RFO as indicated by the score plot of principal component analysis; therefore, CaO and RBO are potential adulterants in RFO.
    Matched MeSH terms: Spectroscopy, Fourier Transform Infrared/methods*
  3. Low ZX, Teo MYM, Nordin FJ, Dewi FRP, Palanirajan VK, In LLA
    Int J Mol Sci, 2022 Oct 25;23(21).
    PMID: 36361655 DOI: 10.3390/ijms232112866
    Curcumin (CUR), a curcuminoid originating from turmeric root, possesses diverse pharmacological applications, including potent anticancer properties. However, the use of this efficacious agent in cancer therapy has been limited due to low water solubility and poor bioavailability. To overcome these problems, a drug delivery system was established as an excipient allowing improved dispersion in aqueous media coupled with enhanced in vitro anticancer effects. Different analyses such as UV-vis spectroscopy, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), solubility and dissolution assays were determined to monitor the successful encapsulation of CUR within the inner cavity of a β-cyclodextrin (β-CD) complex. The results indicated that water solubility was improved by 205.75-fold compared to pure CUR. Based on cytotoxicity data obtained from MTT assays, the inclusion complex exhibited a greater decrease in cancer cell viability compared to pure CUR. Moreover, cancer cell migration rates were decreased by 75.5% and 38.92%, invasion rates were decreased by 37.7% and 35.7%, while apoptosis rates were increased by 26.3% and 14.2%, and both caused caspase 3 activation toward colorectal cancer cells (SW480 and HCT116 cells). This efficacious formulation that enables improved aqueous dispersion is potentially useful and can be extended for various chemotherapeutic applications. Preliminary toxicity evaluation also indicated that its composition can be safely used in humans for cancer therapy.
    Matched MeSH terms: Spectroscopy, Fourier Transform Infrared/methods
  4. Teoh WK, Mohamed Sadiq NS, Saisahas K, Phonchai A, Kunalan V, Md Muslim NZ, et al.
    J Forensic Sci, 2023 Jan;68(1):75-85.
    PMID: 36273275 DOI: 10.1111/1556-4029.15156
    Drugs-facilitated crimes (DFCs) involve the incapacitation of victims under the influence of drugs. Conventionally, a drug administration act is often determined through the examination of biological samples; however, dry residues from any surface, such as drinking glass if related to a DFC could be a potential source of evidence. This study was aimed to establish an attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy coupled with chemometrics for the determination of spiked sedative-hypnotics from dry residues of a drug-spiked beverage. In this study, four sedative-hypnotics, namely diazepam, ketamine, nimetazepam, and xylazine were examined using ATR-FTIR spectroscopy. Subsequently, the ATR-FTIR profiles were compared and decomposed by principal component analysis (PCA) followed by linear discriminant analysis (LDA) for their detection and discrimination. Visual comparison of ATR-FTIR profiles revealed distinct spectra among the tested drugs. An initial unsupervised exploratory PCA model indicated the separation of four main sedative-hypnotics clusters, and the proposed PCA score-LDA model had allowed for a 100% accurate classification. Discrimination of sedative-hypnotics from a dry beverage previously spiked with these drugs was also possible upon an additional extraction procedure. In conclusion, ATR-FTIR coupled with PCA score-LDA model was useful in detecting and discriminating sedative-hypnotics, including those that had been previously spiked into a beverage.
    Matched MeSH terms: Spectroscopy, Fourier Transform Infrared/methods
  5. Eid EEM, Almaiman AA, Alshehade SA, Alsalemi W, Kamran S, Suliman FO, et al.
    Molecules, 2023 May 15;28(10).
    PMID: 37241838 DOI: 10.3390/molecules28104096
    Thymoquinone (TQ) is a quinone derived from the black seed Nigella sativa and has been extensively studied in pharmaceutical and nutraceutical research due to its therapeutic potential and pharmacological properties. Although the chemopreventive and potential anticancer effects of TQ have been reported, its limited solubility and poor delivery remain the major limitations. In this study, we aimed to characterize the inclusion complexes of TQ with Sulfobutylether-β-cyclodextrin (SBE-β-CD) at four different temperatures (293-318 K). Additionally, we compared the antiproliferative activity of TQ alone to TQ complexed with SBE-β-CD on six different cancer cell lines, including colon, breast, and liver cancer cells (HCT-116, HT-29, MDA-MB-231, MCF-7, SK-BR-3, and HepG2), using an MTT assay. We calculated the thermodynamic parameters (ΔH, ΔS, and ΔG) using the van't Holf equation. The inclusion complexes were characterized by X-ray diffraction (XRD), Fourier transforms infrared (FT-IR), and molecular dynamics using the PM6 model. Our findings revealed that the solubility of TQ was improved by ≥60 folds, allowing TQ to penetrate completely into the cavity of SBE-β-CD. The IC50 values of TQ/SBE-β-CD ranged from 0.1 ± 0.01 µg/mL against SK-BR-3 human breast cancer cells to 1.2 ± 0.16 µg/mL against HCT-116 human colorectal cancer cells, depending on the cell line. In comparison, the IC50 values of TQ alone ranged from 0.2 ± 0.01 µg/mL to 4.7 ± 0.21 µg/mL. Overall, our results suggest that SBE-β-CD can enhance the anticancer effect of TQ by increasing its solubility and bioavailability and cellular uptake. However, further studies are necessary to fully understand the underlying mechanisms and potential side effects of using SBE-β-CD as a drug delivery system for TQ.
    Matched MeSH terms: Spectroscopy, Fourier Transform Infrared/methods
  6. Aziz AA, Abdullah Sani MS, Zakaria Z, Abu Bakar NK
    Int J Cosmet Sci, 2023 Aug;45(4):444-457.
    PMID: 36987749 DOI: 10.1111/ics.12854
    BACKGROUND: The employment of Fourier transforms infrared (FT-IR) spectroscopy combined with chemometrics for determination and quantification of lard in a binary blend with palm oil in a cosmetic soap formulations.

    OBJECTIVE: To determine and quantify lard as an adulterant in a binary blend with palm oil in a cosmetic soap formulations by FT-IR and multivariate analysis.

    METHODS: Fatty acids in lard, palm oil and binary blends were extracted via liquid-liquid extraction and were subjected to FTIR spectrometry, combined with principal component analysis (PCA) and discriminant analysis (DA) for the classification of lard in cosmetic soap formulations via two DA models: Model A (percentage of lard in cosmetic soap) and Model B (porcine and non-porcine cosmetic soap). Linear regression (MLR), partial least square regression (PLS-R) and principal components regression (PCR) were used to assess the degree of adulteration of lard in the cosmetic soap.

    FINDINGS: The FTIR spectrum of palm oil slightly differed from that of lard at the wavenumber range of 1453 cm -1 and 1415 cm -1 in palm oil and lard, respectively, indicating the bending vibrations of CH2 and CH3 aliphatic groups and OH carboxyl group respectively. Both of the DA models could accurately classify 100% of cosmetic soap formulations. Nevertheless, less than 100% of verification value was obtained when it was further used to predict the unknown cosmetic soap sample suspected of containing lard or a different percentage of lard. The PCA for Model A and Model B explained a similar cumulative variability (CV) of 92.86% for the whole dataset. MLR and PCR showed the highest determination coefficient (R2) of 0.996, and the lowest relative standard error (RSE) and mean square error (MSE), indicating that both regression models were effective in quantifying the lard adulterant in cosmetic soap.

    CONCLUSION: FTIR spectroscopy coupled with chemometrics with DA, PCA and MLR or PCR can be used to analyse the presence of lard and quantify its percentage in cosmetic soap formulations.

    Matched MeSH terms: Spectroscopy, Fourier Transform Infrared/methods
  7. Panicker CY, Varghese HT, Nayak PS, Narayana B, Sarojini BK, Fun HK, et al.
    PMID: 25863456 DOI: 10.1016/j.saa.2015.03.065
    FT-IR spectrum of (2E)-3-(3-nitrophenyl)-1-[4-piperidin-1-yl]prop-2-en-1-one was recorded and analyzed. The vibrational wavenumbers were computed using HF and DFT quantum chemical calculations. The data obtained from wavenumber calculations are used to assign IR bands. Potential energy distribution was done using GAR2PED software. The geometrical parameters of the title compound are in agreement with the XRD results. NBO analysis, HOMO-LUMO, first and second hyperpolarizability and molecular electrostatic potential results are also reported. The possible electrophile attacking sites of the title molecule is identified using MEP surface plot study. Molecular docking results predicted the anti-leishmanic activity for the compound.
    Matched MeSH terms: Spectroscopy, Fourier Transform Infrared
  8. Dawood S, Koyande AK, Ahmad M, Mubashir M, Asif S, Klemeš JJ, et al.
    Chemosphere, 2021 Sep;278:130469.
    PMID: 33839393 DOI: 10.1016/j.chemosphere.2021.130469
    The present study defines a novel green method for the synthesis of the nickel oxide nanocatalyst by using an aqueous latex extract of the Ficus elastic. The catalyst was examined for the conversion of novel Brachychiton populneus seed oil (BPSO) into biodiesel. The Brachychiton populneus seeds have a higher oil content (41 wt%) and free fatty acid value (3.8 mg KOH/g). The synthesised green nanocatalyst was examined by the Fourier transform infrared (FT-IR) spectroscopy, energy dispersive X-Ray (EDX) spectroscopy, X-Ray diffraction (XRD) spectroscopy and scanning electron microscopy (SEM). The obtained results show that the synthesised green nanocatalyst was 22-26 nm in diameter and spherical-cubic in shape with a higher rate of catalytic efficiency. It was utilised further for the conversion of BPSO into biofuel. Due to the high free fatty acid value, the biodiesel was synthesised by the two-step process, i.e., pretreatment of the BPSO by means of acid esterification and then followed by the transesterification reaction. The acidic catalyst (H2SO4) was used for the pretreatment of BPSO. The optimum condition for the transesterification of the pretreated BPSO was 1:9 of oil-methanol molar ratio, 2.5 wt % of prepared nanocatalyst concentration and 85 °C of reaction temperature corresponding to the highest biodiesel yield of 97.5 wt%. The synthesised biodiesel was analysed by the FT-IR and GC-MS technique to determine the chemical composition of fatty acid methyl esters. Fuel properties of Brachychiton populneus seed oil biodiesel (BPSOB) were also examined, compared, and it falls in the prescribed range of ASTM standards.
    Matched MeSH terms: Spectroscopy, Fourier Transform Infrared
  9. Kamarudin, K.S.N., Chieng, Y.Y., Hamdan, H., Mat, H.
    ASM Science Journal, 2008;2(1):35-44.
    The importance of zeolite surface area and pore volume in adsorption processes has been much reported in literature. In addition to that, structural framework and pore network system may also influence the adsorption capacity and selectivity of methane on zeolite. This paper discusses the characteristics of methane adsorption based on several physical properties of the adsorbents such as surface area, pore volume, pore network system and its interaction with adsorbate. The study, using FTIR spectroscopy showed that the adsorbed methane at room temperature was detected in the FTIR region between 3200 cm–1 – 1200 cm–1. Based on the physical properties of the adsorbents and the FTIR spectra of adsorbed methane, the surface area was not the only factor that determined methane adsorption; in fact the type of pore network system of the adsorbent also affected the interaction, thus affecting the adsorption of methane in zeolite.
    Matched MeSH terms: Spectroscopy, Fourier Transform Infrared
  10. Muhammad FF, Yahya MY, Ketuly KA, Muhammad AJ, Sulaiman K
    PMID: 27372510 DOI: 10.1016/j.saa.2016.06.031
    In this work the optical response, spectroscopic behaviour, and optoelectronic properties of solution and solid state composite systems based on α,ω-dihexylsexithiophene/tris(8-hydroxyquinolinate) gallium (DH6T/Gaq3) are studied upon the incorporation of different molar percentages of Gaq3. UV-vis, PL, FTIR spectrophotometers and SEM technique were utilized to perform the investigations. The results showed a reduced energy band (Eg) (from 2.33eV to 1.83eV) and a broadened absorption spectrum for the blend system when 29.8% molar of Gaq3 was incorporated. These were attributed to the enhanced intermolecular interactions that are brought about by the increased strength of π-π overlap between the molecular moieties. A mathematical formula was developed to interpret the non-monotonic change occurred in Eg, while numerical calculations have been made to assign the type and nature of the electronic transitions governing the spectroscopic behaviour of the system. The results were elaborated and comprehensively discussed in terms of the exciton generation, energy band theory, molecular interactions, and spatial geometry.
    Matched MeSH terms: Spectroscopy, Fourier Transform Infrared
  11. Darfizzi Derawi, Jumat Salimon
    Sains Malaysiana, 2011;40:1123-1127.
    Kajian pengoptimuman tindak balas pengepoksidaan minyak sawit olein (POo) dengan menggunakan mangkin asid performik (HCOOOH) telah dijalankan. Kesan tindak balas terhadap nisbah kepekatan HCOOH : H2O2 dan masa tindak balas telah dikaji pada suhu 45oC. Kandungan oksigen oksirana (OOC) optimum sebanyak 3.61% diperoleh dengan menggunakan nisbah mol 1 : 5 : 2 pada 150 min dan sebanyak 96.5% penukaran dapat dicapai. Hasil tindak balas adalah sebanyak 91.3%. Puncak kromatografi cecair berprestasi tinggi (HPLC) bagi minyak sawit olein terepoksida (EPOo) telah berubah sepenuhnya berbanding puncak HPLC POo. Spektrum transformasi Fourier infra-merah (FTIR) telah menunjukkan kehadiran puncak ikatan gelang oksirana pada 844 cm-1.
    Matched MeSH terms: Spectroscopy, Fourier Transform Infrared
  12. Sharifah Nabihah Syed Jaafar, Sarani Zakaria, Rozaidi Rasid, Nurul Ain Zulkifli, Ali Ahmadzadeh
    Proses pencecairan lignin soda telah dilakukan dengan menggunakan fenol dengan nisbah 1:3. Proses dilakukan selama 90 minit pada suhu 130oC dalam keadaan refluk. Hasil pencecairan iaitu pemfenolan lignin (PL) telah dianalisis dengan Spektrometer Inframerah Transformasi Fourier (FTIR), reometer dan analisis termogravimetri (TGA). Sampel yang disintesis dengan menggunakan asid hidroklorik sebagai mangkin memberikan keputusan yang terbaik. Analisis FTIR menunjukkan kehadiran kumpulan berfungsi yang signifikan seperti gelang aromatik, alkohol dan karbonil. Kesemua sampel PL mematuhi persamaan Arhenius dan bersifat pseudo-plastik. Peratus kehilangan berat sampel dan kadar penguraian sampel PL dipengaruhi oleh jenis mangkin yang digunakan. Sampel PL yang disintesis dikelaskan sebagai biopolimer resin fenolik.
    Matched MeSH terms: Spectroscopy, Fourier Transform Infrared
  13. Muhammad Jefri Mohd Yusof, Nur Aidasyakirah Mohd Tahir, Fazira Firdaus, Siti Fairus M. Yusoff
    Sains Malaysiana, 2018;47:2055-2061.
    Getah asli cecair (LNR) dihasilkan daripada proses penyahpolimeran getah asli yang menghasilkan rantaian polimer
    lebih pendek dan berat molekular kurang daripada 105
    . Namun, LNR masih mempamerkan tahap degradasi dan ketahanan
    termal yang rendah seperti getah asli, disebabkan oleh kehadiran ikatan karbon ganda dua pada rantaian polimer.
    Dalam kajian ini, penurunan diimida menggunakan pengoksidaan hidrazin hidrat dengan hidrogen peroksida dijalankan
    untuk menghidrogenkan unit tidak tepu LNR. LNR terhidrogen (HLNR) dicirikan menggunakan spektrometer infra-merah
    (FTIR) dan spektrometer resonans magnetik nuklear (NMR). Pengoptimuman parameter tindak balas dilakukan dengan
    memanipulasi parameter masa dan suhu tindak balas berdasarkan kaedah rangsangan permukaan (RSM) dengan
    5-aras-2-faktor reka bentuk komposit putaran tengah (CCRD). Satu model kuadratik yang signifikan telah dihasilkan
    untuk menghubungkan dua parameter tersebut dengan nilai R2 adalah 0.9986, menunjukkan bahawa model yang terhasil
    adalah sangat sepadan dengan data uji kaji. Keputusan kajian menunjukkan bahawa peratus penghidrogenan boleh
    ditingkatkan sehingga 91.2%. Seterusnya, berdasarkan RSM, parameter yang optimum bagi penurunan diimida LNR ini
    didapati pada suhu 55.9o
    C selama 6.7 jam, menghasilkan 80.2% HLNR. Kajian ini telah menunjukkan reka bentuk uji kaji
    secara statistik yang novel bagi menghidrogenkan LNR. Pelbagai variasi peratus penghidrogenan produk HLNR dalam
    kajian ini menyumbang kepada lebih banyak aplikasi produk yang memerlukan peratusan ketepuan unit yang tertentu.
    Matched MeSH terms: Spectroscopy, Fourier Transform Infrared
  14. Zhang W, Chen X, Liu G, Jin G, Li Y, Li G, et al.
    PMID: 34619507 DOI: 10.1016/j.saa.2021.120443
    The popularmedicinal mushroomGanodermalucidum was often cultivated by the natural-log. Generally the short log after cultivation were discarded and became pollutant. Rapid and less destructive method of analysis technical by Fourier Transform Infrared (FTIR) and Two-dimension Infrared (2DIR) correlation spectroscopy were selected to determine the composition changes of the logs after G.lucidum cultivation after first year to fifth year. The FTIR accumulated spectra formed without processed baseline showed the samples relied upon a sequenced increase of higher level than spectrum control Q (Q = Quercus acuttisima) from L + Q-5 (L = Lingzhi), L + Q-3, L + Q-1 to L + Q-2. The spectrum L + Q-4 has the optimum highest peak at box B, C and E from this lumped spectral view. The split spectra pinpointed on the fingerprint region of a sample begins from peak 1737 cm-1. ascribed C = O stretching vibration on acetyl and carboxyl hemicellulose group bonding gradually faded from L + Q-1 to L + Q-4 but appeared again on L + Q-5, possibly due to the degradation of hemicellulose. The absorption of peak around 1626 cm-1,1318 cm-1 and 781 cm-1 could be the characteristic absorption peak of calcium oxalate monohydrate. The correlation table indicated, most of the original structure of the building block of the wooden part was deteriorated and marked the lowest correlation value of the 4th year sample with control Q. The sudden changing pattern of 2nd derivative spectrum L + Q-3 to more flatten pattern spectrum L + Q-4 ascribed the changing contents of cellulose and hemicellulose included the lignin within one year during the G. lucidum cultivation. The 2DIR spectrum of the raw material sample precisely showed that the active site with red color was clustered with the area around 1800-1700 cm-1, 1450-800 cm-1 and 750-400 cm-1. In between, the range 1450-800 cm-1 was the most active cluster. Each of the sample showed the different sequence of autopeak comparison. This study has examined the impact of G. lucidum on the degradation of Q. acuttisima in term of their ecosystem life chain. The components of healthy Q. acuttisima wood including lignin, cellulose, hemicellulose and calcium oxalate monohydrate underwent changes after different years of G. lucidum cultivation.
    Matched MeSH terms: Spectroscopy, Fourier Transform Infrared
  15. Yoon TL, Yeap ZQ, Tan CS, Chen Y, Chen J, Yam MF
    PMID: 34627017 DOI: 10.1016/j.saa.2021.120440
    A proof-of-concept medicinal herbs identification scheme using machine learning classifiers is proposed in the form of an automated computational package. The scheme makes use of two-dimensional correlation Fourier Transformed Infrared (FTIR) fingerprinting maps derived from the FTIR of raw herb spectra as digital input. The prototype package admits a collection of 11 machine learning classifiers to form a voting pool. A common set of oversampled dataset containing 5 different herbal classes is used to train the pool of classifiers on a one-verses-others manner. The collections of trained models, dubbed the voting classifiers, are deployed in a collective manner to cast their votes to support or against a given inference fingerprint whether it belongs to a particular class. By collecting the votes casted by all voting classifiers, a logically designed scoring system will select out the most probable guess of the identity of the inference fingerprint. The same scoring system is also capable of discriminating an inference fingerprint that does not belong to any of the classes the voting classifiers are trained for as the 'others' type. The proposed classification scheme is stress-tested to evaluate its performance and expected consistency. Our experimental runs show that, by and large, a satisfactory performance of the classification scheme of up to 90 % accuracy is achieved, providing a proof-of-concept viability that the proposed scheme is a feasible, practical, and convenient tool for herbal classification. The scheme is implemented in the form of a packaged Python code, dubbed the "Collective Voting" (CV) package, which is easily scalable, maintained and used in practice.
    Matched MeSH terms: Spectroscopy, Fourier Transform Infrared
  16. Pandian K, Kalayarasi J, Gopinath SCB
    Biotechnol Appl Biochem, 2022 Dec;69(6):2766-2779.
    PMID: 35287249 DOI: 10.1002/bab.2321
    This study presents a novel sulfur-doped graphitic carbon nitride (S@g-C3 N4 ) with a wider potential range as electrocatalyst for electrochemical sensor application. The S@g-C3 N4 nanosheets were successfully prepared with a ball milling method by mixing appropriate molar concentration required precursors. The as-synthesized heteroatom-doped graphitic carbon nitride is characterized by spectroscopic techniques including PL, DRS-UV, FT-IR, and Brunauer-Emmett-Teller equation. The morphological features were studied by FE-SEM and HR-TEM analysis. Chit-S@g-C3 N4 -modified glassy carbon electrode (GCE) was employed for the electrochemical detection of omeprazole (OMZ) use in drug formulations. We have noted an oxidation peak current response at a potential of +0.8 V versus Ag/AgCl in PBS medium (0.1 M, pH 7.0). Differential pulse voltammetry amperometry experimental method can be used to measure the concentration of OMZ for quantitative studies in known samples. Under the optimized experimental condition, the calibration plot was constructed by plotting the peak currents versus OMZ in the linear ranges from 6.0 × 10-7 to 26 × 10-5  M. The linear regression equation is estimated to be Ip (μA) = 0.9518 (C/μM) + 0.3340 with a good correlation coefficient of 0.9996. The lower determination limit was found to be 20 nM and the current sensitivity was calculated (31.722 μA μM-1  cm-2 ). The developed sensor was utilized successfully to determine the OMZ concentration in drug formulations and biological fluids. These results revealed that the Chit-S@g-C3 N4 -modified GCE showed excellent electroanalytical performance for the detection of OMZ at a low LOD, wider linear range, high sensitivity, good reproducibility, long-term storage stability, and selectivity with an acceptable relative standard deviation value.
    Matched MeSH terms: Spectroscopy, Fourier Transform Infrared
  17. Mohamed Saadon NAF, Taib NI, Loy CW, Mohamed Z
    Sci Rep, 2023 Jan 23;13(1):1246.
    PMID: 36690692 DOI: 10.1038/s41598-023-28296-7
    In this paper, Sr2-xCaxNiWO6 (x = 0.00, 0.02, 0.04, 0.06) were synthesized using a solid-state reaction method. The crystal structure, optical and dielectric properties of the compounds were examined using X-ray diffraction (XRD), scanning electron microscope (SEM) with energy dispersive (EDX) analysis, Ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy and electrochemical impedance spectroscopy respectively. The Rietveld refinement of XRD confirmed that the compounds crystallized in a tetragonal structure with a space group I4/m. According to the SEM images, the grain sizes of the compounds decreased as the dopant increased. The UV-vis analysis revealed that the band gap energy of the compounds decreased from 3.17 eV to 3.13 eV as the amount of doping increased from x = 0.00 to x = 0.06. A dielectric characterization showed that the dielectric constant (ε') and dielectric loss (tan δ) for all compounds possessed a similar trend where it was higher in low-frequency area (~ 1 Hz) and dropped instantaneously with the enhancement of frequency up to 1 MHz until it reached constant values.
    Matched MeSH terms: Spectroscopy, Fourier Transform Infrared
  18. Kiong TC, Nordin N, Ahmad Ruslan NAA, Kan SY, Ismail NM, Zakaria Z, et al.
    Environ Res, 2022 Oct;213:113737.
    PMID: 35752328 DOI: 10.1016/j.envres.2022.113737
    To keep COVID-19 at bay, most countries have mandated the use of face masks in public places and imposed heavy penalties for those who fail to do so. This has inadvertently created a huge demand for disposable face masks and worsened the problem of littering, where a large number of used masks are constantly discarded into the environment. As such, an efficient and innovative waste management strategy for the discarded face mask is urgently needed. This study presents the transformation of discarded face mask into catalyst termed 'mask waste ash catalyst (MWAC)' to synthesise bisindolylmethanes (BIMs), alkaloids that possess antibacterial, antioxidant and antiviral properties. Using commercially available aldehydes and indole, an excellent yield of reaction (62-94%) was achieved using the MWAC in the presence of water as the sole solvent. On the other hand, the FT-IR spectrum of MWAC showed the absorption bands at 2337 cm-1, 1415 cm-1 and 871 cm-1, which correspond to the signals of calcium oxide. It is then proposed that the calcium oxides mainly present in MWAC can protonate oxygen atoms in the carbonyl molecule of the aldehyde group, thus facilitating the nucleophile attack by indole which consequently improved the product yield. Moreover, the MWAC is also observed to facilitate the photodegradation of methylene blue with an efficiency of up to 94.55%. Our results showed the potential applications of the MWAC derived from discarded face masks as a sustainable catalyst for bioactive compound synthesis and photodegradation of dye compounds.
    Matched MeSH terms: Spectroscopy, Fourier Transform Infrared
  19. Rashid T, Sher F, Jusoh M, Joya TA, Zhang S, Rasheed T, et al.
    Environ Res, 2023 Mar 01;220:115160.
    PMID: 36580987 DOI: 10.1016/j.envres.2022.115160
    Humic acid (HA) is a complex organic compound made up of small molecules. A variety of raw materials are used to manufacture HA, due to which the structure and composition of HA vary widely. In this study, nitric acid oxidation of two coal samples from Lakhra (Pakistan) was followed by HA extraction using 2.5, 3.0 and 3.5% KOH solutions. The impact of different operating parameters such as; the effect of KOH concentrations, KOH-coal proportion, extraction time and pH range influencing the HA extraction efficiency was optimally investigated. Commercial HA applications possess numerous challenges, including valuable applications and sub-optimal extraction techniques. A significant limitation of conventional experimental methods is that they can only investigate one component at a time. It is necessary to improve the current processing conditions, this can only be achieved by modelling and optimization of the process conditions to meet market demands. A comprehensive evaluation and prediction of HA extraction using Response Surface Methodology (RSM) are also being reported for the first time in this study. The maximum HA extraction efficiency of 89.32% and 87.04% for coal samples 1 and 2 respectively was achieved with the lowest possible pH of 1.09 (coal sample 1) and 1(coal sample 2), which is remarkably lower as compared to those reported in the literature for conventional alkaline extraction process. The model was evaluated for two coal samples through the coefficient of determination (R2), Root Means Square Error (RMSE), and Mean Average Error (MEE). The results of RSM for coal sample 1 (R2 = 0.9795, RMSE = 4.784) and coal sample 2 (R2 = 0.9758, RMSE = 4.907) showed that the model is well suited for HA extraction efficiency predictions. The derived humic acid from lignite coal was analyzed using elemental analysis, UV-Visible spectrophotometry and Fourier-transformed infrared (FTIR) spectroscopy techniques. Scanning Electron Microscopy (SEM) was applied to analyze the morphological modifications of the extracted HA after treatment with 3.5% KOH solution. For agricultural objectives, such as soil enrichment, enhancing plant growth conditions, and creating green energy solutions, this acquired HA can be made bioactive. This study not only establishes a basis for research into the optimized extraction of HA from lignite coal, but it also creates a new avenue for the efficient and clean use of lignite.
    Matched MeSH terms: Spectroscopy, Fourier Transform Infrared
  20. Lim CC, Shuit SH, Ng QH, Rahim SKEA, Hoo PY, Yeoh WM, et al.
    Environ Sci Pollut Res Int, 2023 Mar;30(14):40242-40259.
    PMID: 36604398 DOI: 10.1007/s11356-022-25064-4
    In view of the simple and rapid conveniency of magnetic separation, magnetic nanocomposites had notably gained attention from researchers for environmental field applications. In this work, carboxylated magnetic multi-walled carbon nanotubes (c-MMWCNTs) and novel sulfonated MMWCNTs (s-MMWCNTs) were synthesized by a facile solvent-free direct doping method. Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscope, energy dispersive X-ray, vibrating sample magnetometer, and point of zero charge analyses confirmed the successful doping of the Fe3O4 nanoparticles into the functionalized MWCNTs to form MMWCNTs. Besides, the bonding stabilities of both c-MMWCNTs and s-MMWCNTs were compared, and results showed that s-MMWCNTs possessed more substantial bonding stability than that of c-MMWCNTs with significantly less leaching amount of Fe3O4. The adsorption capacity of s-MMWCNTs was higher than that of c-MMWCNTs owing to the stronger electronegativity sulfonic group in s-MMWCNTs. Moreover, the reusability experiments proved that the adsorbent remained consistently excellent MB removal efficiency (R > 94%) even reused for twelve cycles of batch adsorption. The finding of the present work highlights the simple fabrication of novel s-MMWCNTs and its potential to be served as a promising and sustainable adsorbent for water remediation owing to its enhanced bonding stability, high adsorption performance, magnetic separability, and supreme recyclability.
    Matched MeSH terms: Spectroscopy, Fourier Transform Infrared
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