MyMedR

In vivo proton magnetic resonance spectroscopy (1H-MRS) evaluation of the metabolite concentration of optic radiation in primary open angle glaucoma

Sidek S, Ramli N, Rahmat K, Ramli NM, Abdulrahman F, Kuo TL

Eur Radiol, 2016 Dec;26(12):4404-4412.

PMID: 26943134

OBJECTIVE: To compare the metabolite concentration of optic radiation in glaucoma patients with that of healthy subjects using Proton Magnetic Resonance Spectroscopy (1H-MRS).

METHODS: 1H-MRS utilising the Single-Voxel Spectroscopy (SVS) technique was performed using a 3.0Tesla MRI on 45 optic radiations (15 from healthy subjects, 15 from mild glaucoma patients, and 15 from severe glaucoma patients). A standardised Volume of Interest (VOI) of 20 × 20 × 20 mm was placed in the region of optic radiation. Mild and severe glaucoma patients were categorised based on the Hodapp-Parrish-Anderson (HPA) classification. Mean and multiple group comparisons for metabolite concentration and metabolite concentration ratio between glaucoma grades and healthy subjects were obtained using one-way ANOVA.

RESULTS: The metabolite concentration and metabolite concentration ratio between the optic radiations of glaucoma patients and healthy subjects did not demonstrate any significant difference (p > 0.05).

CONCLUSION: Our findings show no significant alteration of metabolite concentration associated with neurodegeneration that could be measured by single-voxel 1H-MRS in optic radiation among glaucoma patients.

KEY POINTS: • Glaucoma disease has a neurodegenerative component. • Metabolite changes have been observed in the neurodegenerative process in the brain. • Using SVS, no metabolite changes in optic radiation were attributed to glaucoma.

Matched MeSH terms: Magnetic Resonance Spectroscopy/methods; Proton Magnetic Resonance Spectroscopy/methods*

Fulltext Synthesis and characterization of a novel eco-friendly corrosion inhibition for mild steel in 1 M hydrochloric acid

Al-Amiery AA, Binti Kassim FA, Kadhum AA, Mohamad AB

Sci Rep, 2016 Jan 22;6:19890.

PMID: 26795066 DOI: 10.1038/srep19890

The acid corrosion inhibition process of mild steel in 1 M HCl by azelaic acid dihydrazide has been investigated using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, open circuit potential (OCP) and electrochemical frequency modulation (EFM). Azelaic acid dihydrazide was synthesized, and its chemical structure was elucidated and confirmed using spectroscopic techniques (infrared, nuclear magnetic resonance and mass spectroscopy). Potentiodynamic polarization studies indicate that azelaic acid dihydrazide is a mixed-type inhibitor. The inhibition efficiency increases with increased inhibitor concentration and reaches its maximum of 93% at 5 × 10(-3) M. The adsorption of the inhibitor on a mild steel surface obeys Langmuir's adsorption isotherm. The effect of te perature on corrosion behavior in the presence of 5 × 10(-3) M inhibitor was studied in the temperature range of 30-60 °C. The results indicated that inhibition efficiencies were enhanced with an increase in concentration of inhibitor and decreased with a rise in temperature. To inspect the surface morphology of inhibitor film on the mild steel surface, scanning electron microscopy (SEM) was used before and after immersion in 1.0 M HCl.

Matched MeSH terms: Magnetic Resonance Spectroscopy

Metabolic alteration in obese diabetes rats upon treatment with Centella asiatica extract

Maulidiani, Abas F, Khatib A, Perumal V, Suppaiah V, Ismail A, et al.

J Ethnopharmacol, 2016 Mar 2;180:60-9.

PMID: 26775274 DOI: 10.1016/j.jep.2016.01.001

'Pegaga' is a traditional Malay remedy for a wide range of complaints. Among the 'pegaga', Centella asiatica has been used as a remedy for diabetes mellitus. Thus, we decided to validate this claim by evaluating the in vivo antidiabetic property of C. asiatica (CA) on T2DM rat model using the holistic (1)H NMR-based metabolomics approach.

Matched MeSH terms: Magnetic Resonance Spectroscopy

Polarity dependent photoisomerization of ether substituted azodyes: Synthesis and photoswitching behavior

Gan SM, Pearl ZF, Yuvaraj AR, Lutfor MR, Gurumurthy H

Spectrochim Acta A Mol Biomol Spectrosc, 2015 Oct 5;149:875-80.

PMID: 26004096 DOI: 10.1016/j.saa.2015.05.027

Two new ether substituted azodyes were synthesized and characterized by different spectral analysis such as (1)H NMR, (13)C NMR, FTIR and UV/Vis. Synthesized compounds were used to study the photoisomerization phenomenon by using UV-Vis spectro-photometer. Interesting polarity dependent effect is observed for the first time on these materials. Trans-cis (E-Z) and cis-trans (Z-E) conversion occurred within 41 s and 445 min, respectively for both the compounds in solutions. Polarizing optical microscopy studies revealed that there is no liquid crystal phase for both the compounds. The dramatic variation in the optical property is speculated to be the polarity of the chemical species. These derivatives are useful to fabricate optical data storage devices.

Matched MeSH terms: Magnetic Resonance Spectroscopy

A new chalcone structure of (E)-1-(4-Bromophenyl)-3-(napthalen-2-yl)prop-2-en-1-one: Synthesis, structural characterizations, quantum chemical investigations and biological evaluations

Thanigaimani K, Arshad S, Khalib NC, Razak IA, Arunagiri C, Subashini A, et al.

Spectrochim Acta A Mol Biomol Spectrosc, 2015 Oct 5;149:90-102.

PMID: 25942090 DOI: 10.1016/j.saa.2015.04.028

The structure of (E)-1-(4-Bromophenyl)-3-(napthalen-2-yl)prop-2-en-1-one (C19H13BrO) crystallized in the triclinic system of P-1 space group. The unit cell dimensions are: a=5.8944 (9)Å, b=7.8190 (12)Å, c=16.320 (2)Å, α=102.4364 (19)°, β=95.943 (2)°, γ=96.274 (2)° and Z=2. The physical properties of this compound was determined by the spectroscopic methods (FTIR and (1)H and (13)C NMR). Quantum chemical investigations have been employed to investigate the structural and spectral properties. The molecular structure, vibrational assignments, (1)H and (13)C NMR chemical shift values, non-linear optical (NLO) effect, HOMO-LUMO analysis and natural bonding orbital (NBO) analysis were calculated using HF and DFT/B3LYP methods with 6-311++G(d,p) basis set in the ground state. The results show that the theoretical calculation of the geometrical parameters, vibrational frequencies and chemical shifts are comparable with the experimental data. The crystal structure is influenced and stabilized by weak C-H⋯π interactions connecting the molecules into infinite supramolecular one dimensional ladder-like arrangement. Additionally, this compound is evaluated for their antibacterial activities against gram positive and gram negative strains using a micro dilution procedure and shows activities against a panel of microorganisms.

Matched MeSH terms: Magnetic Resonance Spectroscopy

Synthesis, NMR, FT-IR, X-ray structural characterization, DFT analysis and isomerism aspects of 5-(2,6-dichlorobenzylidene)pyrimidine-2,4,6(1H,3H,5H)-trione

Barakat A, Al-Najjar HJ, Al-Majid AM, Soliman SM, Mabkhot YN, Shaik MR, et al.

Spectrochim Acta A Mol Biomol Spectrosc, 2015 Aug 5;147:107-16.

PMID: 25827772 DOI: 10.1016/j.saa.2015.03.016

The synthesis and spectral characterization of the 5-(2,6-dichlorobenzylidene)pyrimidine-2,4,6(1H,3H,5H)-trione;3 was reported. The solid state molecular structure of 3 was studied using X-ray crystallography. The relative stabilities of the seven possible isomers of 3 were calculated by DFT/B3LYP method using 6-311 G(d,p) basis set. The calculated total energies and thermodynamic parameters were used to predict the relative stabilities of these isomers. The effect of solvent polarity on the relative stability of these isomers was studied at the same level of theory using PCM. It was found that the keto form, (T0), is the most stable isomer both in the gaseous state and solution. In solution, the calculated total energies of all isomers are decreased indicating that all isomers are stabilized by the solvent effect. The vibrational spectra of the most stable isomer, 3(T0) are calculated using the same level of theory and the results are compared with the experimentally measured FTIR spectra. Good correlation was obtained between the experimental and calculated vibrational frequencies (R(2)=0.9992). The electronic spectra of 3(T0) in gas phase as well as in solutions were calculated using the TD-DFT method. All the predicted electronic transitions showed very little spectral shifts and increase in the intensity of absorption due to solvent effect. Also the (1)H- and (13)C-NMR chemical shifts of the stable isomer were calculated and the results were correlated with the experimental data. Good correlations between the experimental and calculated chemical shifts were obtained.

Matched MeSH terms: Magnetic Resonance Spectroscopy

Two new methyl chanofruticosinates from Kopsia flavida blume

Husain K, Jantan I, Said IM, Aimi N, Takayama H

J Asian Nat Prod Res, 2003 Mar;5(1):63-7.

PMID: 12608641

Two new indole alkaloids with the methyl chanofruticosinate skeletal system viz., methyl 3-oxo-12-methoxy-N1-decarbomethoxy-14,15-didehydrochanofruticosinate (1) and methyl 3-oxo-11,12-methylenedioxy-N-decarbomethoxy-14,15-didehydrochanofruticosinate (2), together with four known compounds, methyl 12-methoxy-N1-decarbomethoxychanofruticosinate, methyl 12-methoxychanofruticosinate, methyl 11,12-dimethoxychanofruticosinate and methyl 11,12-methylenedioxy-N1-decarbomethoxychanofruticosinate, were isolated in continuing studies on the leaves of Kopsia flavida Blume. The structures of the new indole alkaloids were assigned by NMR spectral data using various 2D-techniques.

Matched MeSH terms: Magnetic Resonance Spectroscopy

Linear chains in polymeric dicyclohexylammonium tributyl(4-oxo-4H-pyran-2,6-dicarboxylato)stannate and methylphenylammonium tributyl(pyridine-2,6-dicarboxylato)stannate containing trigonal bipyramidal tin

Ng SW, Shanmuga Sundara Raj S, Fun HK, Razak IA, Hook JM

Acta Crystallogr C, 2000 Aug;56 ( Pt 8):966-8.

PMID: 10944291

catena-Poly[dicyclohexylammonium [tributyltin-mu-(4-oxo-4H-pyran-2,6-dicarboxylato-O(2):O( 6))]], (C(12)H(24)N)[Sn(C(7)H(2)O(6))(C(4)H(9))(3)], consists of 4-oxo-4H-pyran-2,6-dicarboxylato groups that axially link adjacent tributyltin units into a linear polyanionic chain. The ammonium counter-ions surround the chain, and each cation forms a pair of hydrogen bonds to the double-bond carbonyl O atoms of the same dianionic group. The chain propagates in a zigzag manner along the c axis of the monoclinic cell. In catena-poly[methyl(phenyl)ammonium [tributyltin-mu-(pyridine-2,6-dicarboxylato-O(2):O(6))]], (C(7)H(10)N)[Sn(C(7)H(3)NO(4))(C(4)H(9))(3)], the pyridine-2, 6-dicarboxylato groups also link the tributyltin groups into a chain, but the hydrogen-bonded chain propagates linearly on the ac face of the monoclinic cell.

Matched MeSH terms: Magnetic Resonance Spectroscopy

Fulltext Chirogenesis and Pfeiffer Effect in Optically Inactive EuIII and TbIII Tris(β-diketonate) Upon Intermolecular Chirality Transfer From Poly- and Monosaccharide Alkyl Esters and α-Pinene: Emerging Circularly Polarized Luminescence (CPL) and Circular Dichroism (CD)

Fujiki M, Wang L, Ogata N, Asanoma F, Okubo A, Okazaki S, et al.

Front Chem, 2020;8:685.

PMID: 32903703 DOI: 10.3389/fchem.2020.00685

We report emerging circularly polarized luminescence (CPL) at 4f-4f transitions when lanthanide (EuIII and TbIII) tris(β-diketonate) embedded to cellulose triacetate (CTA), cellulose acetate butyrate (CABu), D-/L-glucose pentamethyl esters ( D-/ L-Glu), and D-/L-arabinose tetramethyl esters ( D-/ L-Ara) are in film states. Herein, 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionate (fod) and 2,2,6,6-tetramethyl-3,5-heptanedione (dpm) were chosen as the β-diketonates. The glum value of Eu(fod)3 in CABu are +0.0671 at 593 nm (5

D

0

→

7

F1) and -0.0059 at 613 nm (5

D

0

→

7

F2), respectively, while those in CTA are +0.0463 and -0.0040 at these transitions, respectively. The glum value of Tb(fod)3 in CABu are -0.0029 at 490 nm (5

D

4

→

7

F6), +0.0078 at 540 nm (5

D

4

→

7

F5), and -0.0018 at 552 nm (5

D

4

→

7

F5), respectively, while those in CTA are -0.0053, +0.0037, and -0.0059 at these transitions, respectively. D-/ L-Glu and D-/ L-Ara induced weaker glum values at 4f-4f transitions of Eu(fod)3, Tb(fod)3, and Tb(dpm)3. For comparison, Tb(dpm)3 in α-pinene showed clear CPL characteristics, though Eu(dpm)3 did not. A surplus charge neutralization hypothesis was applied to the origin of attractive intermolecular interactions between the ligands and saccharides. This idea was supported from the concomitant opposite tendency in upfield 19F-NMR and downfield 1H-NMR chemical shifts of Eu(fod)3 and the opposite Mulliken charges between F-C bonds (fod) and H-C bonds (CTA and D-/ L-Glu). An analysis of CPL excitation (CPLE) and CPL spectra suggests that (+)- and (-)-sign CPL signals of EuIII and TbIII at different 4f-4f transitions in the visible region are the same with the (+)-and (-)-sign exhibited by CPLE bands at high energy levels of EuIII and TbIII in the near-UV region.

Matched MeSH terms: Proton Magnetic Resonance Spectroscopy

Recovery of cellulose fibers from oil palm empty fruit bunch for pulp and paper using green delignification approach

Yiin CL, Ho S, Yusup S, Quitain AT, Chan YH, Loy ACM, et al.

Bioresour Technol, 2019 Oct;290:121797.

PMID: 31327691 DOI: 10.1016/j.biortech.2019.121797

The aim of this work was to recover the cellulose fibers from EFB using low-transition-temperature-mixtures (LTTMs) as a green delignification approach. The hydrogen bonding of LTTMs observed in 1H NMR tends to disrupt the three-dimensional structure of lignin and further remove the lignin from EFB. Delignification process of EFB strands and EFB powder were performed using standard l-malic acid and cactus malic acid-LTTMs. The recovered cactus malic acid-LTTMs showed higher glucose concentration of 8.07 mg/mL than the recovered l-malic acid LTTMs (4.15 mg/mL). This implies that cactus malic acid-LTTMs had higher delignification efficiency which led to higher amount of cellulose hydrolyzed into glucose. The cactus malic acid-LTTMs-delignified EFB was the most feasible fibers for making paper due to its lowest kappa number of 69.84. The LTTMs-delignified EFB has great potential to be used for making specialty papers in pulp and paper industry.

Matched MeSH terms: Proton Magnetic Resonance Spectroscopy

Cytotoxic xanthones from Garcinia penangiana Pierre

Jabit ML, Khalid R, Abas F, Shaari K, Hui LS, Stanslas J, et al.

Z Naturforsch C J Biosci, 2008 2 16;62(11-12):786-92.

PMID: 18274278

Two new xanthones, characterized as 4-(1,1-dimethylprop-2-enyl)-1,3,5,8-tetrahydroxyxanthone (1) and penangianaxanthone (2), with three known xanthones, cudratricusxanthone H (3), macluraxanthone C (4) and gerontoxanthone C (5), as well as friedelin and stigmasterol were isolated from the leaves of Garcinia penangiana. Their structures were elucidated by analysis of spectroscopic data and comparison of the NMR data with the literature ones. Significant cytotoxicity against DU-145, MCF-7 and NCI-H460 cancer cell lines was demonstrated by compounds 1-5, with IC50 values ranging from 3.5 to 72.8 microM.

Matched MeSH terms: Magnetic Resonance Spectroscopy

Fulltext Free-Radical Photopolymerization of Acrylonitrile Grafted onto Epoxidized Natural Rubber

Whba R, Su'ait MS, Tian Khoon L, Ibrahim S, Mohamed NS, Ahmad A

Polymers (Basel), 2021 Feb 23;13(4).

PMID: 33672185 DOI: 10.3390/polym13040660

The exploitation of epoxidized natural rubber (ENR) in electrochemical applications is approaching its limits because of its poor thermo-mechanical properties. These properties could be improved by chemical and/or physical modification, including grafting and/or crosslinking techniques. In this work, acrylonitrile (ACN) has been successfully grafted onto ENR- 25 by a radical photopolymerization technique. The effect of (ACN to ENR) mole ratios on chemical structure and interaction, thermo-mechanical behaviour and that related to the viscoelastic properties of the polymer was investigated. The existence of the -C≡N functional group at the end-product of ACN-g-ENR is confirmed by infrared (FT-IR) and nuclear magnetic resonance (NMR) analyses. An enhanced grafting efficiency (~57%) was obtained after ACN was grafted onto the isoprene unit of ENR- 25 and showing a significant improvement in thermal stability and dielectric properties. The viscoelastic behaviour of the sample analysis showed an increase of storage modulus up to 150 × 103 MPa and the temperature of glass transition (Tg) was between -40 and 10 °C. The loss modulus, relaxation process, and tan delta were also described. Overall, the ACN-g-ENR shows a distinctive improvement in characteristics compared to ENR and can be widely used in many applications where natural rubber is used but improved thermal and mechanical properties are required. Likewise, it may also be used in electronic applications, for example, as a polymer electrolyte in batteries or supercapacitor.

Matched MeSH terms: Magnetic Resonance Spectroscopy

A new xanthone dimer and cytotoxicity from the stem bark of Calophyllum canum

Taher M, Salleh WMNHW, Alkhamaiseh SI, Ahmad F, Rezali MF, Susanti D, et al.

Z Naturforsch C J Biosci, 2021 Jan 27;76(1-2):87-91.

PMID: 32931451 DOI: 10.1515/znc-2020-0089

A phytochemical investigation of the stem bark of Calophyllum canum resulted in the isolation of a new xanthone dimer identified as biscaloxanthone (1), together with four compounds; trapezifoliaxanthone (2), trapezifolixanthone A (3), taraxerone (4) and taraxerol (5). The structures of these compounds were determined via spectroscopic methods of IR, UV, MS and NMR (1D and 2D). The cytotoxicity of compounds 1-3 were screened against A549, MCF-7, C33A and 3T3L1 cell lines, wherein weak cytotoxic activities were observed (IC50 > 50 μm).

Matched MeSH terms: Magnetic Resonance Spectroscopy

Globrauneine A-F: six new triterpenoid esters from the leaves of Globimetula braunii

Muhammad KJ, Jamil S, Basar N, Sarker SD, Mohammed MG

Nat Prod Res, 2020 Oct;34(19):2746-2753.

PMID: 30931627 DOI: 10.1080/14786419.2019.1586693

Phytochemical study was conducted on the leaves of Globimetula braunii which is a hemi parasitic plant belonging to the family Loranthaceae. Extraction was carried out using cold extraction method with increasing polarity of solvents i.e n-hexane, CH2Cl2 and MeOH. The components were separated by chromatographic technique and the structures of the compounds were elucidated by extensive spectroscopic analyses including MS, FTIR, 1D and 2D NMR, HRMS and chemical methods. Six new pentacyclic triterpenoid esters named as globrauneine A (1), globrauneine B (2), globrauneine C (3), globrauneine D (4), globrauneine E (5), and globrauneine F (6), together with six known compounds (7 - 12) were successfully isolated from the leaves of G. braunii growing on Piliostigma thonningii. These results depict a substantial support to the chemotaxonomy of the genus Globimetula.

Matched MeSH terms: Magnetic Resonance Spectroscopy

Metabolite variations and antioxidant activity of Muntingia calabura leaves in response to different drying methods and ethanol ratios elucidated by NMR-based metabolomics

Zolkeflee NKZ, Isamail NA, Maulidiani M, Abdul Hamid NA, Ramli NS, Azlan A, et al.

Phytochem Anal, 2021 Jan;32(1):69-83.

PMID: 31953888 DOI: 10.1002/pca.2917

INTRODUCTION: Muntingia calabura from the Muntingiaceae family has been documented for several medicinal uses. The combinations of drying treatment and extracting solvents for a plant species need to be determined and optimised to ensure that the extracts contain adequate amounts of the bioactive metabolites.

OBJECTIVE: Evaluate the metabolite variations and antioxidant activity among M. calabura leaves subjected to different drying methods and extracted with different ethanol ratios using proton nuclear magnetic resonance (1 H-NMR)-based metabolomics. Methodology The antioxidant activity of M. calabura leaves dried with three different drying methods and extracted with three different ethanol ratios was determined by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and nitric oxide (NO) scavenging assays. The metabolites variation among the extracts and correlation with antioxidant activity were analysed by 1 H-NMR-based metabolomics.

RESULTS: Muntingia calabura leaves extracted with 50% and 100% ethanol from air-drying and freeze-drying methods had the highest total phenolic content and the lowest IC50 value for the DPPH scavenging activity. Meanwhile, oven-dried leaves extracted with 100% ethanol had the lowest IC50 value for the NO scavenging activity. A total of 43 metabolites, including sugars, organic acids, amino acids, phytosterols, phenolics and terpene glycoside were tentatively identified. A noticeable discrimination was observed in the different ethanol ratios by the principal component analysis. The partial least-squares analysis suggested that 32 compounds out of 43 compounds identified were the contributors to the bioactivities.

CONCLUSION: The results established set the preliminary steps towards developing this plant into a high value product for phytomedicinal preparations.

Matched MeSH terms: Magnetic Resonance Spectroscopy

Fulltext Capsule endoscopy in inflammatory bowel disease: when and how

Hilmi I, Kobayashi T

Intest Res, 2020 Jul;18(3):265-274.

PMID: 32623876 DOI: 10.5217/ir.2019.09165

Capsule endoscopy (CE) is emerging as an important investigation in inflammatory bowel disease (IBD); common types include the standard small bowel CE and colon CE. More recently, the pan-enteric CE was developed to assess the large and small bowel in patients with Crohn's disease (CD). Emerging indications include noninvasive assessment for mucosal healing (both in the small bowel and the colon) and detection of postoperative recurrence in patients with CD. Given the increasing adoption, several CE scoring systems have been specifically developed for IBD. The greatest concern with performing CE, particularly in CD, is capsule retention, but this can be overcome by performing cross-sectional imaging such as magnetic resonance enterography and using patency capsules before performing the procedure. The development of software for automated detection of mucosal abnormalities typically seen in IBD may further increase its adoption.

Matched MeSH terms: Magnetic Resonance Spectroscopy

Synthesis, characterization, and anti-cancer activity of new chalcone derivatives containing naphthalene and fluorine moieties

Lim YH, Oo CW, Koh RY, Voon GL, Yew MY, Yam MF, et al.

Drug Dev Res, 2020 Jul 28.

PMID: 32720715 DOI: 10.1002/ddr.21715

In recent years, chalcones and their derivatives have become the focus of global scientists due to increasing evidence reported towards their potency in antitumor and anti-cancer. Here, the chalcones designed and synthesized in our present study were derived from the derivatives of naphthaldehyde and acetophenone. Both these precursors have been reported in demonstrating a certain degree of anticancer property. Also, the substituents on these precursors such as hydroxyl, methoxy, prenyl, and chloro were shown able to enhance the anticancer efficiency. Hence, it is the interest of the current study to investigate the anticancer potential of the hybrid molecules (chalcones) consisting of these precursors with different alkoxy substituents and with or without the fluorine moiety. Two series of chalcone derivatives were designed, synthesized, and characterized using the elemental analysis, IR, 1 H and 13 C NMR spectroscopy, subsequently evaluated for their anti-cancer activity. Interestingly, the results showed that the fluorinated chalcones 11-15 exhibited stronger cytotoxic activity towards the breast cancer cell lines (4T1) compared to non-fluorinated chalcone derivatives. Remarkably, the selectivity index obtained for these fluorinated chalcones derivatives against the breast cancer 4T1 cell line was higher than those exhibited by cisplatin, which is one of the most frequently deployed chemotherapy agents in current medical practice. These findings could provide an insight towards the potential of fluorinated chalcones being developed as an anti-cancer agent with moderate activity towards breast cancer cell and low inhibition of fibroblast cell at a concentration of 100 μM.

Matched MeSH terms: Magnetic Resonance Spectroscopy

An NMR-compatible microfluidic platform enabling in situ electrochemistry

Davoodi H, Nordin N, Bordonali L, Korvink JG, MacKinnon N, Badilita V

Lab Chip, 2020 08 26;20(17):3202-3212.

PMID: 32734975 DOI: 10.1039/d0lc00364f

Combining microfluidic devices with nuclear magnetic resonance (NMR) has the potential of unlocking their vast sample handling and processing operation space for use with the powerful analytics provided by NMR. One particularly challenging class of integrated functional elements from the perspective of NMR are conductive structures. Metallic electrodes could be used for electrochemical sample interaction for example, yet they can cause severe NMR spectral and SNR degradation. These issues are more entangled at the micro-scale since the distorted volume occupies a higher ratio of the sample volume. In this study, a combination of simulation and experimental validation was used to identify an electrode geometry that, in terms of NMR spectral parameters, performs as well as for the case when no electrodes are present. By placing the metal tracks in the side-walls of a microfluidic channel, we found that NMR RF excitation performance was actually enhanced, without compromising B0 homogeneity. Monitoring in situ deposition of chitosan in the microfluidic platform is presented as a proof-of-concept demonstration of NMR characterisation of an electrochemical process.

Matched MeSH terms: Magnetic Resonance Spectroscopy

Fulltext Conductivity studies of schiff base ligands derived from O-phenylenediamine and their Co(II) and Zn(II) complexes

Muhamad Faridz Osman, Karimah Kassim

Scientific Research Journal, 2015;12(2):0-0.

MyJurnal

The coordination complexes of Co(II) and Zn(II) with Schiff bases derived from ophenylenediamine and substituted 2-hydroxybenzaldehyde were prepared. All compounds were characterized by Fourier transform infrared (FTIR) spectroscopy and Nuclear magnetic resonance (NMR) spectroscopy elemental analyzers. They were analyzed using impedance spectroscopy in the frequency range of 100Hz - 1MHz. L1 and L2 showed higher conductivity compared to their metal
complexes, which had values of 1.37 x 10-7 and 6.13 x 10-8S/cm respectively.

Matched MeSH terms: Magnetic Resonance Spectroscopy

Fulltext Brain activations evoked by passive and active listening: a preliminary study on multiple subjects

Ahmad Nazlim Yusoff, Mazlyfarina Mohamad, Mohd Mahadir Ayob, Mohd Harith Hashim

Jurnal Sains Kesihatan Malaysia, 2008;6(1):35-60.

MyJurnal

A functional magnetic resonance imaging (fMRI) study was conducted on 4 healthy male and female subjects to investigate brain activation during passive and active listening. Two different experimental conditions were separately used in this study. The first condition requires the subjects to listen to a simple arithmetic instruction (e.g. one-plus-two-plus-three-plus-four) - passive listening. In the second condition, the subjects were given the same series of arithmetic instruction and were required to listen and perform the calculation - active listening. The data were then analysed using the Statistical Parametric Mapping (SPM5) and the MATLAB 7.4 (R2007a) programming softwares. The results obtained from the fixed (FFX) and random effects analyses (RFX) show that the active-state signal intensity was significantly higher (p < 0.05) than the resting-state signal intensity for both conditions. The results also indicate significant differences (p < 0.001) in brain activation between passive and active listening. The activated cortical regions during passive listening, as obtained from the FFX of the first condition is symmetrical in the left and right temporal and frontal lobes covering the cortical auditory areas. However, for the second condition, which was active listening, more activation occurs in the left hemisphere with a reduction in the number of activated voxels and their signal intensity in the right hemisphere. Activation mainly occurs in the middle temporal gyrus, precentral gyrus, middle frontal gyrus, superior temporal gyrus and several other areas in the frontal lobes. The point of maximum signal intensity has been shifted to a new coordinates during active listening. It is also observed that the magnetic resonance signal intensity and the number of activated voxel in the right and left superior temporal lobes for the second condition have been reduced as compared to that of the first condition. The results obtained strongly suggest the existence of functional specialisation. The results also indicate different networks for the two conditions. These networks clearly pertain to the existence of functional connectivity between activation areas during listening and listening while performing a simple arithmetic task.

Matched MeSH terms: Magnetic Resonance Spectroscopy

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