Displaying publications 101 - 120 of 596 in total

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  1. Rajan ST, Narasimhan M, Rao KB, Jacob TE
    J Oral Maxillofac Pathol, 2019 9 14;23(2):303.
    PMID: 31516245 DOI: 10.4103/jomfp.JOMFP_297_18
    Background: Xylene is one of the most commonly used solvents in industrial and medical technologies. Several health hazards of xylene have been documented in literature. Workers in certain forces appear to have the greatest potential for exposure to high concentrations of xylene - histopathology technicians and painters are two such groups. This study was undertaken with the aim to determine the level of xylene exposure and the various systemic health effects among these groups.

    Methodology: The study was performed by analyzing the urine samples of the participants for methylhippuric acid, the established biomarker of xylene with the aid of high-performance liquid chromatography.

    Results and Conclusion: The work hours per week of the occupationally exposed participants were statistically analyzed with that of the excretory values of the metabolites of xylene, and the P value was found to be highly significant. Various side effects of xylene including respiratory, dermatological, neurological and gastrointestinal symptoms were observed among the study groups.

    Matched MeSH terms: Solvents
  2. Dzulkharnien NSF, Karim MR, Zahid NI, Rahman NMMA, Abdullah I, Salleh NM
    J Fluoresc, 2019 Jul;29(4):1049-1056.
    PMID: 31338718 DOI: 10.1007/s10895-019-02418-9
    The optical properties of a series of side chain liquid crystalline polymers (P1-P3) containing azo-benzothiazole mesogen with different terminal substituents (-H, -CH3 and -OCH2CH3) in four organic solvents of varying polarity have been investigated by absorption and fluorescence spectral analysis. Solvatochromic studies of P1-P3 did not show any regular variation on the absorption and emission intensities with changing the polarity of solvent. Theoretical studies were performed based on different solvent correlation methods such as Dimroth-Reichardt and Kamlet-Taft methods to investigate the solute-solvent interactions. Both absorption and emission maxima of investigated polymers were bathochromically shifted with the replacement of sixth position hydrogen atom by electron donating groups in benzothiazole moiety. The emission intensities of the studied polymers showed decreasing trend with increasing temperature.
    Matched MeSH terms: Solvents
  3. Nur Atiqah Zaharulli
    ESTEEM Academic Journal, 2020;16(2):88-95.
    MyJurnal
    Questioned document examination becomes a great interest and one of the broad fields in forensic science. It involves the analysis of ink, handwriting and signature examination, paper’s physical structure analysis and the ageing of a document. Ink analysis in forensic document examination is a challenging process. Questioned documents examiners are dealing with unknown source of ink and minute sample size. Ink extraction needs to be done before the ink analysis. 17 gel pen ink samples were chosen in this study. Solubility test has been done to determine the degree of solubility of ink in a variety of organic solvents. Extraction solvent optimization is a process to evaluate the efficiency of organic solvents to extract ink samples. Ethanoic acid showed the ability to dissolve most of the ink samples and displayed maximum absorbance of UV-Vis spectra.
    Matched MeSH terms: Solvents
  4. Arumugham T, K R, Hasan SW, Show PL, Rinklebe J, Banat F
    Chemosphere, 2021 May;271:129525.
    PMID: 33445028 DOI: 10.1016/j.chemosphere.2020.129525
    Recently, supercritical fluid CO2 extraction (SFE) has emerged as a promising and pervasive technology over conventional extraction techniques for various applications, especially for bioactive compounds extraction and environmental pollutants removal. In this context, temperature and pressure regulate the solvent density and thereby effects the yield, selectivity, and biological/therapeutic properties of the extracted components. However, the nature of plant matrices primarily determines the extraction mechanism based on either density or vapor pressure. The present review aims to cover the recent research and developments of SFE technique in the extraction of bioactive plant phytochemicals with high antioxidant, antibacterial, antimalarial, and anti-inflammatory activities, influencing parameters, process conditions, the investigations for improving the yield and selectivity. In another portion of this review focuses on the ecotoxicology and toxic metal recovery applications. Nonpolar properties of Sc-CO2 create strong solvent strength via distinct intermolecular interaction forces with micro-pollutants and toxic metal complexes. This results in efficient removal of these contaminants and makes SFE technology as a superior alternative for conventional solvent-based treatment methods. Moreover, a compelling assessment on the therapeutic, functional, and solvent properties of SFE is rarely focused, and hence this review would add significant value to the SFE based research studies. Furthermore, we mention the limitations and potential of future perspectives related to SFE applications.
    Matched MeSH terms: Solvents
  5. Lau EV, Gan S, Ng HK
    Int J Anal Chem, 2010;2010:398381.
    PMID: 20396670 DOI: 10.1155/2010/398381
    This paper aims to provide a review of the analytical extraction techniques for polycyclic aromatic hydrocarbons (PAHs) in soils. The extraction technologies described here include Soxhlet extraction, ultrasonic and mechanical agitation, accelerated solvent extraction, supercritical and subcritical fluid extraction, microwave-assisted extraction, solid phase extraction and microextraction, thermal desorption and flash pyrolysis, as well as fluidised-bed extraction. The influencing factors in the extraction of PAHs from soil such as temperature, type of solvent, soil moisture, and other soil characteristics are also discussed. The paper concludes with a review of the models used to describe the kinetics of PAH desorption from soils during solvent extraction.
    Matched MeSH terms: Solvents
  6. Shamsudin N, Tan AL, Wimmer FL, Young DJ, Tiekink ER
    Acta Crystallogr E Crystallogr Commun, 2015 Sep 1;71(Pt 9):1026-31.
    PMID: 26396840 DOI: 10.1107/S2056989015014280
    The asymmetric unit of the title compound, 2[Zn(C32H16N8)(C7H9N)]·3C7H9N, comprises two independent complex mol-ecules and three benzyl-amine solvent mol-ecules. Each complex mol-ecule features a penta-coordinated Zn(2+) ion within a square-pyramidal geometry, whereby the N5 donor set is defined by four atoms of the phthalocyaninate dianion (PC) and an N-bound benzyl-amine mol-ecule; it is the relative orientations of the latter that differentiate between the independent complex mol-ecules. The uncoordinated benzyl-amine mol-ecules display different conformations in the structure, with syn-Car-Car-Cm-N (ar = aromatic, m = methyl-ene) torsion angles spanning the range -28.7 (10) to 35.1 (14)°. In the crystal, N-H⋯N and N-H⋯π inter-actions lead to supra-molecular layers in the ab plane. The layers have a zigzag topology, have the coordinating and non-coordinating benzyl-amine mol-ecules directed to the inside, and present the essentially flat PC resides to the outside. This arrangement enables adjacent layers to associate via π-π inter-actions [inter-centroid distance between pyrrolyl and fused-benzene rings = 3.593 (2) Å] so that a three-dimensional architecture is formed.
    Matched MeSH terms: Solvents
  7. Yeo CI, Tan YS, Tiekink ER
    Acta Crystallogr E Crystallogr Commun, 2015 Aug 1;71(Pt 8):937-40.
    PMID: 26396760 DOI: 10.1107/S2056989015013341
    In the title complex salt, [Au2{(C6H5)2PCH2P(C6H5)2}]Cl2·(CH3)2C=O·H2O, the dication forms an eight-membered {-PCPAu}2 ring with a transannular aurophilic inter-action [Au⋯Au = 2.9743 (2) Å]. The ring approximates a flattened boat conformation, with the two methyl-ene C atoms lying ca 0.58-0.59 Å above the least-squares plane defined by the Au2P4 atoms (r.m.s. deviation = 0.0849 Å). One Cl(-) anion functions as a weak bridge between the Au(I) atoms [Au⋯Cl = 2.9492 (13) and 2.9776 (12) Å]. The second Cl(-) anion forms two (water)O-H⋯Cl hydrogen bonds about a centre of inversion, forming a centrosymmetric eight-membered {⋯HOH⋯Cl}2 supra-molecular square. Globally, the dications and loosely associated Cl(-) anions assemble into layers lying parallel to the ac plane, being connected by C-H⋯Cl,π(phen-yl) inter-actions. The supra-molecular squares and solvent acetone mol-ecules are sandwiched in the inter-layer region, being connected to the layers on either side by C-H⋯Cl,O(acetone) inter-actions.
    Matched MeSH terms: Solvents
  8. Zhan SZ, Chen W, Zheng J, Ng SW, Li D
    Dalton Trans, 2021 Jan 18.
    PMID: 33459321 DOI: 10.1039/d0dt03661g
    Five luminescent polymorphic aggregates of trinuclear Cu(i)-pyrazolate, namely [anti-Cu3L3]2 (1), [syn-Cu3L3·C2H5OH]2 (2), [anti-Cu3L3·C2H5OH]n (3), [anti-Cu3L3·0.5C7H8]n (4) and [syn-Cu3L3·C8H10]n (5) (HL = 4-(pyridin-4-ylthio)-3,5-dimethyl-1H-pyrazole), were reported. The trimeric Cu3L3 fragments present syn- and anti-conformations dependent on the dangled direction of 4-pyridyl groups on the two sides of the Cu3Pz3 plane (Pz = pyrazolate). Intertrimeric NPyCu weak coordination bonds associate these Cu3L3 fragments together to form dimeric or polymeric structures, which are further stabilized by crystallized solvent molecules or intertrimeric CuCu interactions. The solvated complexes (3-5) may be transformed into the unsolvated complex 1 by evacuation of the crystallized solvents upon heating. All these complexes emit from green to yellow under UV irradiation, which originated from the triplet excited states of metal to ligand charge transfer (3MLCT) mixed with intertrimeric CuCu interactions. This work provides a novel kind of supramolecular aggregate based on Cu3Pz3 beyond the classical π-acidbase adducts and metallophilicity-dependent dimers/oligomers.
    Matched MeSH terms: Solvents
  9. Salma H, Melha YM, Sonia L, Hamza H, Salim N
    J Pharm Sci, 2021 06;110(6):2531-2543.
    PMID: 33548245 DOI: 10.1016/j.xphs.2021.01.032
    The purpose of this study was to simultaneously predict the drug release and skin permeation of Piroxicam (PX) topical films based on Chitosan (CTS), Xanthan gum (XG) and its Carboxymethyl derivatives (CMXs) as matrix systems. These films were prepared by the solvent casting method, using Tween 80 (T80) as a permeation enhancer. All of the prepared films were assessed for their physicochemical parameters, their in vitro drug release and ex vivo skin permeation studies. Moreover, deep learning models and machine learning models were applied to predict the drug release and permeation rates. The results indicated that all of the films exhibited good consistency and physicochemical properties. Furthermore, it was noticed that when T80 was used in the optimal formulation (F8) based on CTS-CMX3, a satisfactory drug release pattern was found where 99.97% of PX was released and an amount of 1.18 mg/cm2 was permeated after 48 h. Moreover, Generative Adversarial Network (GAN) efficiently enhanced the performance of deep learning models and DNN was chosen as the best predictive approach with MSE values equal to 0.00098 and 0.00182 for the drug release and permeation kinetics, respectively. DNN precisely predicted PX dissolution profiles with f2 values equal to 99.99 for all the formulations.
    Matched MeSH terms: Solvents
  10. Mohd Abdul Fatah Abdul Manan, M. Ibrahim M. Tahir, Crouse, Karen A., How, Fiona N.-F., Watkin, David J.
    MyJurnal
    The crystal structure of the title compound has been determined. The compound crystallized in the triclinic space group P -1, Z = 2, V = 1839.42(18) Å3 and unit cell parameters a = 11.0460(6) Å, b = 13.3180(7) Å, c = 13.7321(8) Å, a = 80.659(3)°, ß = 69.800(3)° and ? = 77.007(2)° with one disordered dimethylsulfoxide solvent molecule with the sulfur and oxygen atoms are distributed over two sites; S101/S102 [site occupancy factors: 0.6035/0.3965] and O130/O131 [site occupancy factor 0.3965/0.6035]. The C22-S21 and C19-S20 bond distances of 1.779(7) Å and 1.788(8) Å indicate that both of the molecules are connected by the disulfide bond [S20-S21 2.055(2) Å] in its thiol form. The crystal structure reveals that both of the 5-bromoisatin moieties are trans with respect to the [S21-S20 and C19-N18] and [S20-S21 and C22-N23] bonds whereas the benzyl group from the dithiocarbazate are in the cis configuration with respect to [S21-S20 and C19-S44] and [S20-S21 and C22-S36] bonds. The crystal structure is further stabilized by intermolecular hydrogen bonds of N9-H35···O16 formed between the two molecules and N28-H281···O130, N28-H281···O131 and C41-H411···O131 with the solvent molecule.
    Matched MeSH terms: Solvents
  11. Aminah, A., Zuhair, A., Amira, K.
    MyJurnal
    The aim of this study was to determine the antioxidant activities of dietary bitter melon fruit supplemented in male rat model. In this study, three common tests for measuring antioxidant activity of the bitter melon were evaluated using 2, 2-diphenyl-l-picrylhydrazyl assay (DPPH assay), total phenolic acid assay (TPC assay) and Ferric reducing ability of plasma assa. (FRAP assay). Results showed that the extracting solvent significantly (P
    Matched MeSH terms: Solvents
  12. Kassim, K.M., Davarnejad, R.
    ASM Science Journal, 2007;1(2):143-154.
    MyJurnal
    The objective of this paper is to model the extraction of carotenoid with supercritical carbon dioxide as the solvent. Experimental data for the high pressure vapour-liquid phase equilibrium of the binary system carbon dioxide-carotenoid was reviewed for the elevated temperatures of 313.15, 323.15, 333.15 K and pressures up to 500 bar. The experimental data was correlated and modeled using Redlich-Kwong equation of state and regular solution methods. The use of the equation of state as an empirical correlation for collating and predicting liquid-liquid and liquid-dense fluid equilibria is discussed. It was concluded that the estimation of some of the parameters required for these calculations would be difficult if the solute (carotenoid) was a complex substance about which little was known apart from its structural formula. An alternative procedure is to apply activity coefficient expression of the regular solution theory type to each phase. Calculations along these lines are described and the physical basis for applying these methods under the relevant conditions is discussed. The regular solution theory approach in particular was found to be encouraging for the mutual miscibility calculations for heavy components (such as carotenoid) particularly for substances sensitive to temperature, though the interaction parameters for he prediction activity coefficients must be regarded as pressure dependent.
    Matched MeSH terms: Solvents
  13. Yiin CL, Quitain AT, Yusup S, Uemura Y, Sasaki M, Kida T
    Bioresour Technol, 2018 Aug;261:361-369.
    PMID: 29680702 DOI: 10.1016/j.biortech.2018.04.039
    Natural hydro-low-transition-temperature mixtures (NH-LTTMs) tend to be the most favorable next-generation green solvents for biomass pretreatment, as they are cheap and environmental friendly. The amount of water bound into the NH-LTTMs greatly affected their thermal stability, whereby the highest thermal stability was observed with the water content of 7.6 wt%. It is worth noting that, the highest molar transition energy of NH-LTTMs (47.57 kcal mol-1), which indicated the highest solubility, was optimized with the molar ratio of hydrogen bond donor (HBD)-hydrogen bond acceptor (HBA)-water (2:4:3) at a temperature of 60 °C. Hydrogen bonding networks of the NH-LTTMs, which led to the dissolution of biomass, were confirmed by the alteration in the peaks of the involved bonds and resonance signal to lower field through FTIR and 1H NMR spectra, respectively. The components evidenced in high-resolution mass spectra of extracted lignin showed its high potential to be valorized into useful fuels and chemicals.
    Matched MeSH terms: Solvents
  14. Nurazwa Ishak, Ahmad Firdaus Lajis, Rosfarizan Mohamad, Arbakariya Ariff, Murni Halim, Helmi Wasoh
    MyJurnal
    In this paper, the syntheses of kojic acid esters via chemical and enzymatic methods are
    reviewed. The advantages and disadvantages of chemical process in term of process, safety and
    efficiency are discussed. In enzymatic process, the significant process parameters related to the
    synthesis of kojic acid esters such as the lipases, solvent, temperature and water content are
    highlighted. Possible enzymatic synthesis using solvent and solvent-free system taking into
    consideration of the difference in these systems involving cost, lipase reusability and efficiency
    is comparatively reviewed. The possible approach for large scale production using various
    enzyme reactor designs is also discussed and re-evaluated.
    Matched MeSH terms: Solvents
  15. Sasidharan S, Darah I, Jain K
    The effect of season on yield and quality of organic solvent extracts from Gracilaria changii was determined. The sustainability of the bioactive compound of G. changii from Malaysia was investigated by using the TLC and FTIR standards methods. Studies was carried out to examine the sustainability of the bioactive compound in the various extract obtained from G. changii collected from Pantai Morib, Beach Selangor Malaysia on bimonthly for a period of one year in 2003. This study revealed that the bioactive compounds was present all over the year but with different quantities. In general the variation in yield or quantities of bioactive compound was related to environment. G. changii can be considered a candidate for drug development since it retained the number of bioactive compound.
    Matched MeSH terms: Solvents
  16. Amir S, Othman R, Subban R, Mohamed N
    Sains Malaysiana, 2011;40:1179-1186.
    Solid polymer electrolytes comprised of various weight percent ratios of poly(ethyl methacrylate) (PEMA) and lithium perchlorate (LiClO4) salt were prepared via solution casting technique using N,N-dimethylformamide (DMF) as the solvent. The conductivity values of the electrolytes were determined via impedance spectroscopy. The conductivity of the PEMA-LiClO4 electrolytes increased with increasing salt concentration and the highest conductivity obtained was in the order of 10-6 S cm-1 at salt concentration of 20 wt%. The conductivity decreased for higher salt concentration. In order to understand the conductivity behavior, XRD and dielectric studies were done. The results showed that the conductivity was influenced by the fraction of amorphous region and number of charge carriers in the system. The transference number measurement was also performed on the highest conducting electrolyte systems. The result of the measurement indicated that the systems were ionic conductors.
    Matched MeSH terms: Solvents
  17. Mat Nawi NI, Abd Halim NS, Lee LC, Wirzal MDH, Bilad MR, Nordin NAH, et al.
    Polymers (Basel), 2020 Jan 21;12(2).
    PMID: 31973178 DOI: 10.3390/polym12020252
    The competitiveness of algae as biofuel feedstock leads to the growth of membrane filtration as one of promising technologies for algae harvesting. Nanofiber membrane (NFM) was found to be efficient for microalgae harvesting via membrane filtration, but it is highly limited by its weak mechanical strength. The main objective of this study is to enhance the applicability of nylon 6,6 NFM for microalgae filtration by optimizing the operational parameters and applying solvent vapor treatment to improve its mechanical strength. The relaxation period and filtration cycle could be optimized to improve the hydraulic performance. For a cycle of 5 min., relaxation period of ≤2 min shows the highest steady-state permeability of 365 ± 14.14 L m-2 h-1 bar-1, while for 10 min cycle, 3 min. of relaxation period was found optimum that yields permeability of 402 ± 34.47 L m-2 h-1 bar-1. The treated nylon 6,6 NFM was also used to study the effect of aeration rate. It is confirmed that the aeration rate enhances the steady-state performance for both intermittent and continuous mode of aeration. Remarkably, intermittent aeration shows 7% better permeability than the full aeration for all tested condition, which is beneficial for reducing the total energy consumption.
    Matched MeSH terms: Solvents
  18. Liu J, Xuan D, Chai J, Guo D, Huang Y, Liu S, et al.
    ACS Omega, 2020 May 05;5(17):10011-10020.
    PMID: 32391489 DOI: 10.1021/acsomega.0c00365
    A mild and effective synthesis of resorcinol-furfural (RF) thermosetting resin was proposed with ethanol as a distinctive solvent, which, as a usually neglected factor, was shown to not only help form a homogeneous reaction system but also observably reduce the energy barriers between the early intermediates and transition states in addition reactions by explicit solvent effects, drawn from theoretical calculation conclusions. Besides, the para-additions on aromatic rings were more dominant than ortho-additions with the same reactants, which affected the final link types of monomers verified by Fourier transform infrared spectroscopy and two-dimensional nuclear magnetic resonance tests. The prepared resin can be assigned to a relatively fast gel speed and a high residual mass (65.25%) after pyrolysis in a N2 atmosphere by adjusting the molar ratios of F to R, and the curing of that was a complex reaction, with a curing temperature around 149 °C and an activation energy of about 49.11 kJ mol-1 obtained by the Kissinger method.
    Matched MeSH terms: Solvents
  19. Lee CY, Ooi IH
    PMID: 27618068 DOI: 10.3390/ph9030054
    Temozolomide (TMZ) is one of the most effective chemotherapeutic agents for glioblastoma multiforme, but the required high administration dose is accompanied by side effects. To overcome this problem and to further improve TMZ's efficacy, targeted delivery of TMZ by using polymeric nanoparticles has been explored. We synthesised the PLGA-PEG-FOL copolymer and attempted encapsulation of TMZ into PLGA-PEG-FOL nanoparticles using the emulsion solvent evaporation method and the nanoprecipitation method. Conjugation of PEG and FOL to PLGA has been reported to be able to increase the delivery of TMZ to the brain as well as targeting the glioma cells. However, despite making numerous modifications to these methods, the loading of TMZ in the nanoparticles only ranged between 0.2% and 2%, and the nanoparticles were between 400 nm and 600 nm in size after freeze-drying. We proceed with determining the release profile of TMZ in phosphate buffered saline (PBS). Our initial data indicated that TMZ was slowly released from the nanoparticles. The metabolite of TMZ rather than the parent compound was detected in PBS. Our study suggests that while PLGA-PEG-FOL can be used as a polymeric or encapsulation material for central delivery of TMZ, a practical and cost effective formulation method is still far from reach.
    Matched MeSH terms: Solvents
  20. Hakimi M, Omar MB, Ibrahim R
    Sensors (Basel), 2023 Jan 16;23(2).
    PMID: 36679816 DOI: 10.3390/s23021020
    The gas sweetening process removes hydrogen sulfide (H2S) in an acid gas removal unit (AGRU) to meet the gas sales' specification, known as sweet gas. Monitoring the concentration of H2S in sweet gas is crucial to avoid operational and environmental issues. This study shows the capability of artificial neural networks (ANN) to predict the concentration of H2S in sweet gas. The concentration of N-methyldiethanolamine (MDEA) and Piperazine (PZ), temperature and pressure as inputs, and the concentration of H2S in sweet gas as outputs have been used to create the ANN network. Two distinct backpropagation techniques with various transfer functions and numbers of neurons were used to train the ANN models. Multiple linear regression (MLR) was used to compare the outcomes of the ANN models. The models' performance was assessed using the mean absolute error (MAE), root mean square error (RMSE), and coefficient of determination (R2). The findings demonstrate that ANN trained by the Levenberg-Marquardt technique, equipped with a logistic sigmoid (logsig) transfer function with three neurons achieved the highest R2 (0.966) and the lowest MAE (0.066) and RMSE (0.122) values. The findings suggested that ANN can be a reliable and accurate prediction method in predicting the concentration of H2S in sweet gas.
    Matched MeSH terms: Solvents
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