Displaying publications 1 - 20 of 149 in total

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  1. Application of Conductive Hydrogels on Spinal Cord Injury Repair: A Review
    Shahemi NH, Mahat MM, Asri NAN, Amir MA, Ab Rahim S, Kasri MA
    ACS Biomater Sci Eng, 2023 Jul 10;9(7):4045-4085.
    PMID: 37364251 DOI: 10.1021/acsbiomaterials.3c00194
    Spinal cord injury (SCI) causes severe motor or sensory damage that leads to long-term disabilities due to disruption of electrical conduction in neuronal pathways. Despite current clinical therapies being used to limit the propagation of cell or tissue damage, the need for neuroregenerative therapies remains. Conductive hydrogels have been considered a promising neuroregenerative therapy due to their ability to provide a pro-regenerative microenvironment and flexible structure, which conforms to a complex SCI lesion. Furthermore, their conductivity can be utilized for noninvasive electrical signaling in dictating neuronal cell behavior. However, the ability of hydrogels to guide directional axon growth to reach the distal end for complete nerve reconnection remains a critical challenge. In this Review, we highlight recent advances in conductive hydrogels, including the incorporation of conductive materials, fabrication techniques, and cross-linking interactions. We also discuss important characteristics for designing conductive hydrogels for directional growth and regenerative therapy. We propose insights into electrical conductivity properties in a hydrogel that could be implemented as guidance for directional cell growth for SCI applications. Specifically, we highlight the practical implications of recent findings in the field, including the potential for conductive hydrogels to be used in clinical applications. We conclude that conductive hydrogels are a promising neuroregenerative therapy for SCI and that further research is needed to optimize their design and application.
    Matched MeSH terms: Electric Conductivity
  2. Fulltext Performance Analysis of Jatropha Oil-Based Polyurethane Acrylate Gel Polymer Electrolyte for Dye-Sensitized Solar Cells
    Rayung M, Aung MM, Su'ait MS, Chuah Abdullah L, Ahmad A, Lim HN
    ACS Omega, 2020 Jun 23;5(24):14267-14274.
    PMID: 32596563 DOI: 10.1021/acsomega.9b04348
    Biobased polymers are useful materials in substituting conventional petroleum-derived polymers because of their good properties, ready availability, and abundance in nature. This study reports a new jatropha oil-based gel polymer electrolyte (GPE) for use in dye-sensitized solar cells (DSSCs). The GPE was prepared by mixing jatropha oil-based polyurethane acrylate (PUA) with different concentrations of lithium iodide (LiI). The GPE was characterized by infrared spectroscopy, thermal analysis, lithium nuclear magnetic resonance analysis, electrochemical analysis, and photocurrent conversion efficiency. The highest room-temperature ionic conductivity of 1.88 × 10-4 S cm-1 was obtained at 20 wt % of LiI salt. Additionally, the temperature-dependent ionic conductivity of the GPE exhibited Arrhenius behavior with an activation energy of 0.42 eV and a pre-exponential factor of 1.56 × 103 S cm-1. The electrochemical stability study showed that the PUA GPE was stable up to 2.35 V. The thermal stability of the gel electrolyte showed an improvement after the addition of the salt, suggesting a strong intermolecular interaction between PUA and Li, which leads to polymer-salt complexation, as proven by Fourier transform infrared spectroscopy analysis. A DSSC has been assembled using the optimum ionic conductivity gel electrolyte which indicated 1.2% efficiency under 1 sun condition. Thus, the jatropha oil-based GPE demonstrated favorable properties that make it a promising alternative to petroleum-derived polymer electrolytes in DSSCs.
    Matched MeSH terms: Electric Conductivity
  3. Fulltext Electron-phonon coupling constants of two-dimensional copper oxide-based high temperature superconductors
    R. Abd-Shukor, W.Y. Lim
    ASM Science Journal, 2013;7(1):18-22.
    MyJurnal
    The electron-phonon coupling constant of the copper oxide-based high temperature superconductors in the van Hove scenario was calculated using three known models and by employing various acoustic data. Three expressions for the transition temperature from the models were used to calculate the constants. All three models assumed a logarithmic singularity in the density of states near the Fermi surface. The calculated electron-phonon coupling constant ranged from 0.06 to 0.28. The constants increased with the transition temperature indicating a strong correlation between electron-phonon coupling and superconductivity in these materials. These values were smaller than the values estimated for the conventional three-dimensional BCS theory. The results were compared with previous reports on direct measurements of electron-phonon coupling constants in the copper oxide based superconductors.
    Matched MeSH terms: Electric Conductivity
  4. Tough Supramolecular Polymer Networks with Extreme Stretchability and Fast Room-Temperature Self-Healing
    Liu J, Tan CSY, Yu Z, Li N, Abell C, Scherman OA
    Adv Mater, 2017 Jun;29(22).
    PMID: 28370560 DOI: 10.1002/adma.201605325
    Recent progress on highly tough and stretchable polymer networks has highlighted the potential of wearable electronic devices and structural biomaterials such as cartilage. For some given applications, a combination of desirable mechanical properties including stiffness, strength, toughness, damping, fatigue resistance, and self-healing ability is required. However, integrating such a rigorous set of requirements imposes substantial complexity and difficulty in the design and fabrication of these polymer networks, and has rarely been realized. Here, we describe the construction of supramolecular polymer networks through an in situ copolymerization of acrylamide and functional monomers, which are dynamically complexed with the host molecule cucurbit[8]uril (CB[8]). High molecular weight, thus sufficient chain entanglement, combined with a small-amount dynamic CB[8]-mediated non-covalent crosslinking (2.5 mol%), yields extremely stretchable and tough supramolecular polymer networks, exhibiting remarkable self-healing capability at room temperature. These supramolecular polymer networks can be stretched more than 100× their original length and are able to lift objects 2000× their weight. The reversible association/dissociation of the host-guest complexes bestows the networks with remarkable energy dissipation capability, but also facile complete self-healing at room temperature. In addition to their outstanding mechanical properties, the networks are ionically conductive and transparent. The CB[8]-based supramolecular networks are synthetically accessible in large scale and exhibit outstanding mechanical properties. They could readily lead to the promising use as wearable and self-healable electronic devices, sensors and structural biomaterials.
    Matched MeSH terms: Electric Conductivity
  5. Materials and Techniques for Implantable Nutrient Sensing Using Flexible Sensors Integrated with Metal-Organic Frameworks
    Ling W, Liew G, Li Y, Hao Y, Pan H, Wang H, et al.
    Adv Mater, 2018 Jun;30(23):e1800917.
    PMID: 29633379 DOI: 10.1002/adma.201800917
    The combination of novel materials with flexible electronic technology may yield new concepts of flexible electronic devices that effectively detect various biological chemicals to facilitate understanding of biological processes and conduct health monitoring. This paper demonstrates single- or multichannel implantable flexible sensors that are surface modified with conductive metal-organic frameworks (MOFs) such as copper-MOF and cobalt-MOF with large surface area, high porosity, and tunable catalysis capability. The sensors can monitor important nutriments such as ascorbicacid, glycine, l-tryptophan (l-Trp), and glucose with detection resolutions of 14.97, 0.71, 4.14, and 54.60 × 10-6 m, respectively. In addition, they offer sensing capability even under extreme deformation and complex surrounding environment with continuous monitoring capability for 20 d due to minimized use of biological active chemicals. Experiments using live cells and animals indicate that the MOF-modified sensors are biologically safe to cells, and can detect l-Trp in blood and interstitial fluid. This work represents the first effort in integrating MOFs with flexible sensors to achieve highly specific and sensitive implantable electrochemical detection and may inspire appearance of more flexible electronic devices with enhanced capability in sensing, energy storage, and catalysis using various properties of MOFs.
    Matched MeSH terms: Electric Conductivity
  6. Breast imaging using electrical impedance tomography: correlation of quantitative assessment with visual interpretation
    Zain NM, Chelliah KK
    Asian Pac J Cancer Prev, 2014;15(3):1327-31.
    PMID: 24606460
    BACKGROUND: Electrical impedance tomography (EIT) is a new non-invasive, mobile screening method which does not use ionizing radiation to the human breast; allows conducting quantitative assessment of the images besides the visual interpretation. The aim of this study was to correlate the quantitative assessment and visual interpretation of breast electrical impedance tomographs and associated factors.

    MATERIALS AND METHODS: One hundred and fifty mammography patients above 40 years and undergoing EIT were chosen using convenient sampling. Visual interpretation of the images was carried out by a radiologist with minimum of three years experience using the breast imaging - electrical impedance (BI-EIM) classification for detection of abnormalities. A set of thirty blinded EIT images were reinterpreted to determine the intra-rater reliability using kappa. Quantitative assessment was by comparison of the breast average electric conductivity with the norm and correlations with visual interpretation of the images were determined using Chi-square. One-way ANOVA was used to compare the mean electrical conductivity between groups and t-test was used for comparisons with pre-existing Caucasians statistics. Independent t-tests were applied to compare the mean electrical conductivity of women with factors like exogenous hormone use and family history of breast cancer.

    RESULTS: The mean electrical conductivity of Malaysian women was significantly lower than that of Caucasians (p<0.05). Quantitative assessment of electrical impedance tomography was significantly related with visual interpretation of images of the breast (p<0.05).

    CONCLUSIONS: Quantitative assessment of electrical impedance tomography images was significantly related with visual interpretation.

    Matched MeSH terms: Electric Conductivity
  7. A comparison of brain phantom relative permittivity with CST simulation library and existing research
    Chew KM, Seman N, Sudirman R, Yong CY
    Biomed Mater Eng, 2014;24(6):2161-7.
    PMID: 25226914 DOI: 10.3233/BME-141027
    The development of human-like brain phantom is important for data acquisition in microwave imaging. The characteristics of the phantom should be based on the real human body dielectric properties such as relative permittivity. The development of phantom includes the greymatter and whitematter regions, each with a relative permittivity of 38 and 28 respectively at 10 GHz frequency. Results were compared with the value obtained from the standard library of Computer Simulation Technology (CST) simulation application and the existing research by Fernandez and Gabriel. Our experimental results show a positive outcome, in which the proposed mixture was adequate to represent real human brain for data acquisition.
    Matched MeSH terms: Electric Conductivity
  8. Fulltext Determination of mineral, trace element, and pesticide levels in honey samples originating from different regions of Malaysia compared to manuka honey
    Moniruzzaman M, Chowdhury MA, Rahman MA, Sulaiman SA, Gan SH
    Biomed Res Int, 2014;2014:359890.
    PMID: 24982869 DOI: 10.1155/2014/359890
    The present study was undertaken to determine the content of six minerals, five trace elements, and ten pesticide residues in honeys originating from different regions of Malaysia. Calcium (Ca), magnesium (Mg), iron (Fe), and zinc (Zn) were analyzed by flame atomic absorption spectrometry (FAAS), while sodium (Na) and potassium (K) were analyzed by flame emission spectrometry (FAES). Trace elements such as arsenic (As), lead (Pb), cadmium (Cd), copper (Cu), and cobalt (Co) were analyzed by graphite furnace atomic absorption spectrometry (GFAAS) following the microwave digestion of honey. High mineral contents were observed in the investigated honeys with K, Na, Ca, and Fe being the most abundant elements (mean concentrations of 1349.34, 236.80, 183.67, and 162.31 mg/kg, resp.). The concentrations of the trace elements were within the recommended limits, indicating that the honeys were of good quality. Principal component analysis reveals good discrimination between the different honey samples. The pesticide analysis for the presence of organophosphorus and carbamates was performed by high performance liquid chromatography (HPLC). No pesticide residues were detected in any of the investigated honey samples, indicating that the honeys were pure. Our study reveals that Malaysian honeys are rich sources of minerals with trace elements present within permissible limits and that they are free from pesticide contamination.
    Matched MeSH terms: Electric Conductivity
  9. Fulltext Effect of Root Restriction on the Growth, Photosynthesis Rate, and Source and Sink Relationship of Chilli (Capsicum annuum L.) Grown in Soilless Culture
    Zakaria NI, Ismail MR, Awang Y, Megat Wahab PE, Berahim Z
    Biomed Res Int, 2020;2020:2706937.
    PMID: 32090071 DOI: 10.1155/2020/2706937
    Chilli (Capsicum annum L.) plant is a high economic value vegetable in Malaysia, cultivated in soilless culture containers. In soilless culture, the adoption of small container sizes to optimize the volume of the growing substrate could potentially reduce the production cost, but will lead to a reduction of plant growth and yield. By understanding the physiological mechanism of the growth reduction, several potential measures could be adopted to improve yield under restricted root conditions. The mechanism of growth reduction of plants subjected to root restriction remains unclear. This study was conducted to determine the physiological mechanism of growth reduction of root-restricted chilli plants grown in polyvinyl-chloride (PVC) column of two different volumes, 2392 cm3(root-restricted) and 9570 cm3(control) in soilless culture. Root restriction affected plant growth, physiological process, and yield of chilli plants. Root restriction reduced the photosynthesis rate and photochemical activity of PSII, and increased relative chlorophyll content. Limited root growth in root restriction caused an accumulation of high levels of sucrose in the stem and suggested a transition of the stem as a major sink organ for photoassimilate. Growth reduction in root restriction was not related to limited carbohydrate production, but due to the low sink demand from the roots. Reduction of the total yield per plant about, 23% in root restriction was concomitant, with a slightly increased harvest index which reflected an increased photoassimilate partitioning to the fruit production and suggested more efficient fruits production in the given small plant size of root restriction.
    Matched MeSH terms: Electric Conductivity
  10. Effects of aeration rate on degradation process of oil palm empty fruit bunch with kinetic-dynamic modeling
    Talib AT, Mokhtar MN, Baharuddin AS, Sulaiman A
    Bioresour Technol, 2014 Oct;169:428-38.
    PMID: 25079208 DOI: 10.1016/j.biortech.2014.07.033
    The effect of different aeration rates on the organic matter (OM) degradation during the active phase of oil palm empty fruit bunch (EFB)-rabbit manure co-composting process under constant forced-aeration system has been studied. Four different aeration rates, 0.13 L min(-1) kg(DM)(-1),0.26 L min(-1) kg(DM)(-1),0.49 L min(-1) kg(DM)(-1) and 0.74 L min(-1) kg(DM)(-1) were applied. 0.26 L min(-1) kg(DM)(-1) provided enough oxygen level (10%) for the rest of composting period, showing 40.5% of OM reduction that is better than other aeration rates. A dynamic mathematical model describing OM degradation, based on the ratio between OM content and initial OM content with correction functions of moisture content, free air space, oxygen and temperature has been proposed.
    Matched MeSH terms: Electric Conductivity
  11. Comparison of the carbon-sequestering abilities of pineapple leaf residue chars produced by controlled combustion and by field burning
    Leng LY, Husni MH, Samsuri AW
    Bioresour Technol, 2011 Nov;102(22):10759-62.
    PMID: 21958525 DOI: 10.1016/j.biortech.2011.08.131
    This study was undertaken to compare the chemical properties and yields of pineapple leaf residue (PLR) char produced by field burning (CF) with that produced by a partial combustion of air-dried PLR at 340 °C for 3 h in a furnace (CL). Higher total C, lignin content, and yield from CL as well as the presence of aromatic compounds in the Fourier Transform Infrared spectra of the char produced from CL suggest that the CL process was better in sequestering C than was the CF process. Although the C/N ratio of char produced from CL was low indicating a high N content of the char, the C in the char produced from CL was dominated by lignin suggesting that the decomposition of char produced from CL would be slow. To sequester C by char application, the PLR should be combusted in a controlled process rather than by burning in the field.
    Matched MeSH terms: Electric Conductivity
  12. Evaluation of thermochemical pretreatment and continuous thermophilic condition in rice straw composting process enhancement
    Hosseini SM, Abdul Aziz H
    Bioresour Technol, 2013 Apr;133:240-7.
    PMID: 23428821 DOI: 10.1016/j.biortech.2013.01.098
    The effects of thermochemical pretreatment and continuous thermophilic conditions on the composting of a mixture of rice straw residue and cattle manure were investigated using a laboratory-scale composting reactor. Results indicate that the composting period of rice straw can be shortened to less than 10 days by applying alkali pre-treatment and continuous thermophilic composting conditions. The parameters obtained on day 9 of this study are similar to the criteria level published by the Canadian Council of Ministers of the Environment. The moisture content, organic matter reduction, pH level, electrical conductivity, total organic carbon reduction, soluble chemical oxygen demand reduction, total Kjeldahl nitrogen, carbon-to-nitrogen ratio, and germination index were 62.07%, 16.99%, 7.30%, 1058 μS/cm, 17.00%, 83.43%, 2.06%, 16.75%, and 90.33%, respectively. The results of this study suggest that the application of chemical-biological integrated processes under thermophilic conditions is a novel method for the rapid degradation and maturation of rice straw residue.
    Matched MeSH terms: Electric Conductivity
  13. Performance variation according to anode-embedded orientation in a sediment microbial fuel cell employing a chessboard-like hundred-piece anode
    An J, Nam J, Kim B, Lee HS, Kim BH, Chang IS
    Bioresour Technol, 2015 Aug;190:175-81.
    PMID: 25941759 DOI: 10.1016/j.biortech.2015.04.071
    The effect of two different anode-embedding orientations, lengthwise- and widthwise-embedded anodes was explored, on the performance of sediment microbial fuel cells (SMFCs) using a chessboard anode. The maximum current densities and power densities in SMFCs having lengthwise-embedded anodes (SLA1-SLA10) varied from 38.2mA/m(2) to 121mA/m(2) and from 5.5mW/m(2) to 20mW/m(2). In comparison, the maximum current densities and maximum power densities in SMFCs having anodes widthwise-embedded between 0cm to 8cm (SWA2-SWA5) increased from 82mA/m(2) to 140mA/m(2) and from 14.7mW/m(2) to 31.1mW/m(2) as the anode depth became deeper. Although there was a difference in the performance among SWA5-SWA10, it was considered negligible. Hence, it is concluded that it is important to embed anodes widthwise at the specific anode depths, in order to improve of SMFC performance. Chessboard anode used in this work could be a good option for the determination of optimal anode depths.
    Matched MeSH terms: Electric Conductivity
  14. Synergetic effect of conductive polymer poly(3,4-ethylenedioxythiophene) with different structural configuration of anode for microbial fuel cell application
    Kang YL, Ibrahim S, Pichiah S
    Bioresour Technol, 2015;189:364-369.
    PMID: 25913883 DOI: 10.1016/j.biortech.2015.04.044
    PEDOT was synthesized by chemical polymerisation and characterised for its electrochemical insights. Three different anode configuration, namely graphite plate (GP), carbon cloth (CC) and graphite felt (GF) were then loaded with a fixed amount of PEDOT (2.5 mg/m(2)) denoted as GP-P, CC-P and GF-P respectively. The PEDOT coating improved the electrochemical characteristics and electron transfer capabilities of the anodes. They also contributed for enhanced MFC performances with maximum energy generation along with coulombic efficiency than the unmodified anodes. The morphological characteristics like higher surface area and open structure of felt material promoted both microbial formation and electrochemical active area. A maximum current density of 3.5A/m(2) was achieved for GF-P with CE and COD of 51% and 86% respectively. Thus, the GF-P anode excelled among the studied anodes with synergetic effect of PEDOT coating and structural configuration, making it as a potential optimum anode for MFC application.
    Matched MeSH terms: Electric Conductivity*
  15. Fulltext Effective composting of empty fruit bunches using potential Trichoderma strains
    Siddiquee S, Shafawati SN, Naher L
    Biotechnol Rep (Amst), 2017 Mar;13:1-7.
    PMID: 28352555 DOI: 10.1016/j.btre.2016.11.001
    Oil palm fibres are easy to degrade, eco-friendly in nature and once composted, they can be categorized under nutrient-enriched biocompost. Biocompost is not only a good biofertilizer but also a good biocontrol agent against soil-borne pathogens. In this research, experimental works on the composting of empty fruit bunches (EFB) from the oil palm industry were conducted using two potential Trichoderma strains. Analysis of pH initially found the soils to be slightly acidic. However, after composting, the soils were found to be alkaline. Trichoderma propagules increased by 72% in the soils compared to other fungi. Soil electrical conductivity was found to be 50.40 μS/cm for compost A, 42.10 μS/cm for compost B and 40.11 μS/cm for the control. The highest C:N ratio was obtained for compost A at 3.33, followed by compost B at 2.79, and then the control at 1.55. The highest percentages of nitrogen (N), phosphorus (P), and potassium (K) were found in compost A (0.91:2.13:6.68), which was followed by compost B (0.46:0.83:5.85) and then the control (0.32:0.26:5.76). Thus, the biocomposting of oil palm fibres shows great potential for enhancing soil micronutrient, plant growth performance, and crop yield production.
    Matched MeSH terms: Electric Conductivity
  16. Assessment of metals distribution and microbial contamination at selected lake waters in and around Miri City, East Malaysia
    Prasanna MV, Nagarajan R, Chidambaram S, Elayaraja A
    Bull Environ Contam Toxicol, 2012 Sep;89(3):507-11.
    PMID: 22684361 DOI: 10.1007/s00128-012-0698-4
    A baseline study was carried out to assess the metal concentrations and microbial contamination at selected Lake waters in and around Miri City, East Malaysia. Sixteen surface water samples were collected at specific Lakes in the environs of major settlement areas and recreational centers in Miri City. The Physico-chemical parameters [pH, Electrical Conductivity (EC) and Dissolved Oxygen (DO)], metals (Fe, Mn, Cu, Cd, Ni and Zn) and Escherichia coli (E. coli) were analysed. The concentrations of Fe, Mn and Ni have been found to be above the permissible limits of drinking water quality standards. The metals data have also been used for the calculation of heavy metal pollution index. Higher values of E. coli indicate microbial contamination in the Lake waters.
    Matched MeSH terms: Electric Conductivity
  17. Characterization of conducting cellulose acetate based polymer electrolytes doped with "green" ionic mixture
    Ramesh S, Shanti R, Morris E
    Carbohydr Polym, 2013 Jan 2;91(1):14-21.
    PMID: 23044100 DOI: 10.1016/j.carbpol.2012.07.061
    Polymer electrolytes were developed by solution casting technique utilizing the materials of cellulose acetate (CA), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and deep eutectic solvent (DES). The DES is synthesized from the mixture of choline chloride and urea of 1:2 ratios. The increasing DES content well plasticizes the CA:LiTFSI:DES matrix and gradually improves the ionic conductivity and chemical integrity. The highest conducting sample was identified for the composition of CA:LiTFSI:DES (28 wt.%:12 wt.%:60 wt.%), which has the greatest ability to retain the room temperature ionic conductivity over the entire 30 days of storage time. The changes in FTIR cage peaks upon varying the DES content in CA:LiTFSI:DES prove the complexation. This complexation results in the collapse of CA matrix crystallinity, observed from the reduced intensity of XRD diffraction peaks. The DES-plasticized sample is found to be more heat-stable compared to pure CA. Nevertheless, the addition of DES diminishes the CA:LiTFSI matrix's heat-resistivity but at the minimum addition the thermal stability is enhanced.
    Matched MeSH terms: Electric Conductivity*
  18. Electrical, structural, thermal and electrochemical properties of corn starch-based biopolymer electrolytes
    Liew CW, Ramesh S
    Carbohydr Polym, 2015 Jun 25;124:222-8.
    PMID: 25839815 DOI: 10.1016/j.carbpol.2015.02.024
    Biopolymer electrolytes containing corn starch, lithium hexafluorophosphate (LiPF6) and ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate (BmImPF6) are prepared by solution casting technique. Temperature dependence-ionic conductivity studies reveal Vogel-Tamman-Fulcher (VTF) relationship which is associated with free volume theory. Ionic liquid-based biopolymer electrolytes show lower glass transition temperature (Tg) than ionic liquid-free biopolymer electrolyte. X-ray diffraction (XRD) studies demonstrate higher amorphous region of ionic liquid-added biopolymer electrolytes. In addition, the potential stability window of the biopolymer electrolyte becomes wider and stable up to 2.9V. Conclusively, the fabricated electric double layer capacitor (EDLC) shows improved electrochemical performance upon addition of ionic liquid into the biopolymer electrolyte. The specific capacitance of EDLC based on ionic liquid-added polymer electrolyte is relatively higher than that of ionic liquid-free polymer electrolyte as depicted in cyclic voltammogram.
    Matched MeSH terms: Electric Conductivity
  19. Electrochemical exfoliation of graphite in nanofibrillated kenaf cellulose (NFC)/surfactant mixture for the development of conductive paper
    Ardyani T, Mohamed A, Abu Bakar S, Sagisaka M, Umetsu Y, Hafiz Mamat M, et al.
    Carbohydr Polym, 2020 Jan 15;228:115376.
    PMID: 31635739 DOI: 10.1016/j.carbpol.2019.115376
    The effect of incorporating common dodecyl anionic and cationic surfactants such as dodecyltrimethylammonium bromide (DTAB), dodecylethyldimethylammonium bromide (DDAB), and sodium dodecylsulfate (SDS) in nanocomposites of reduced graphene oxide and nanocellulose are described. The stabilization and electrical properties of the nanocomoposites of reduced graphene oxide (RGO) and nanofibrillated kenaf cellulose (NFC) were characterized using four-point probe electrical conductivity measurements. Raman spectroscopy, field emission scanning electron microscopy, and high-resolution transmission electron microscopy were used to investigate dispersion morphology and the quality of RGO inside the NFC matrices. Small-angle neutron scattering (SANS) was used to study the aggregation behavior of the aqueous surfactant systems and RGO dispersions. The cationic surfactant DTAB proved to be the best choice for stabilization of RGO in NFC, giving enhanced electrical conductivity five orders of magnitude higher than the neat NFC. The results highlight the effects of hydrophilic surfactant moieties on the structure, stability and properties of RGO/NFC composites.
    Matched MeSH terms: Electric Conductivity
  20. Fulltext Quantitative intrinsic auto-cathodoluminescence can resolve spectral signatures of tissue-isolated collagen extracellular matrix
    Zielinski MS, Vardar E, Vythilingam G, Engelhardt EM, Hubbell JA, Frey P, et al.
    Commun Biol, 2019;2:69.
    PMID: 30793047 DOI: 10.1038/s42003-019-0313-x
    By analyzing isolated collagen gel samples, we demonstrated in situ detection of spectrally deconvoluted auto-cathodoluminescence signatures of specific molecular content with precise spatial localization over a maximum field of view of 300 µm. Correlation of the secondary electron and the hyperspectral images proved ~40 nm resolution in the optical channel, obtained due to a short carrier diffusion length, suppressed by fibril dimensions and poor electrical conductivity specific to their organic composition. By correlating spectrally analyzed auto-cathodoluminescence with mass spectroscopy data, we differentiated spectral signatures of two extracellular matrices, namely human fibrin complex and rat tail collagen isolate, and uncovered differences in protein distributions of isolated extracellular matrix networks of heterogeneous populations. Furthermore, we demonstrated that cathodoluminescence can monitor the progress of a human cell-mediated remodeling process, where human collagenous matrix was deposited within a rat collagenous matrix. The revealed change of the heterogeneous biological composition was confirmed by mass spectroscopy.
    Matched MeSH terms: Electric Conductivity
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