Displaying publications 1 - 20 of 54 in total

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  1. Perspectives on cultivation and harvesting technologies of microalgae, towards environmental sustainability and life cycle analysis
    Soudagar MEM, Kiong TS, Jathar L, Nik Ghazali NN, Ramesh S, Awasarmol U, et al.
    Chemosphere, 2024 Apr;353:141540.
    PMID: 38423144 DOI: 10.1016/j.chemosphere.2024.141540
    The development of algae is seen as a potential and ecologically sound approach to address the increasing demands in multiple sectors. However, successful implementation of processes is highly dependent on effective growing and harvesting methods. The present study provides a complete examination of contemporary techniques employed in the production and harvesting of algae, with a particular emphasis on their sustainability. The review begins by examining several culture strategies, encompassing open ponds, closed photobioreactors, and raceway ponds. The analysis of each method is conducted in a systematic manner, with a particular focus on highlighting their advantages, limitations, and potential for expansion. This approach ensures that the conversation is in line with the objectives of sustainability. Moreover, this study explores essential elements of algae harvesting, including the processes of cell separation, dewatering, and biomass extraction. Traditional methods such as centrifugation, filtration, and sedimentation are examined in conjunction with novel, environmentally concerned strategies including flocculation, electro-coagulation, and membrane filtration. It evaluates the impacts on the environment that are caused by the cultivation process, including the usage of water and land, the use of energy, the production of carbon dioxide, and the runoff of nutrients. Furthermore, this study presents a thorough examination of the current body of research pertaining to Life Cycle Analysis (LCA) studies, presenting a perspective that emphasizes sustainability in the context of algae harvesting systems. In conclusion, the analysis ends up with an examination ahead at potential areas for future study in the cultivation and harvesting of algae. This review is an essential guide for scientists, policymakers, and industry experts associated with the advancement and implementation of algae-based technologies.
  2. Fulltext Research on Cartilage 3D Printing Technology Based on SA-GA-HA
    Chen Y, Gong Y, Shan L, Tan CY, Al-Furjan MS, Ramesh S, et al.
    Materials (Basel), 2023 Jul 28;16(15).
    PMID: 37570016 DOI: 10.3390/ma16155312
    Cartilage damage is difficult to heal and poses a serious problem to human health as it can lead to osteoarthritis. In this work, we explore the application of biological 3D printing to manufacture new cartilage scaffolds to promote cartilage regeneration. The hydrogel made by mixing sodium alginate (SA) and gelatin (GA) has high biocompatibility, but its mechanical properties are poor. The addition of hydroxyapatite (HA) can enhance its mechanical properties. In this paper, the preparation scheme of the SA-GA-HA composite hydrogel cartilage scaffold was explored, the scaffolds prepared with different concentrations were compared, and better formulations were obtained for printing and testing. Mathematical modeling of the printing process of the bracket, simulation analysis of the printing process based on the mathematical model, and adjustment of actual printing parameters based on the results of the simulation were performed. The cartilage scaffold, which was printed using Bioplotter 3D printer, exhibited useful mechanical properties suitable for practical needs. In addition, ATDC-5 cells were seeded on the cartilage scaffolds and the cell survival rate was found to be higher after one week. The findings demonstrated that the fabricated chondrocyte scaffolds had better mechanical properties and biocompatibility, providing a new scaffold strategy for cartilage tissue regeneration.
  3. Fulltext Fabrication and characterization of graphene oxide-based polymer nanocomposite coatings, improved stability and hydrophobicity
    Kumar SSA, M NB, Batoo KM, Wonnie Ma IA, Ramesh K, Ramesh S, et al.
    Sci Rep, 2023 Jun 02;13(1):8946.
    PMID: 37268705 DOI: 10.1038/s41598-023-35154-z
    In this study, acrylic-epoxy-based nanocomposite coatings loaded with different concentrations (0.5-3 wt.%) of graphene oxide (GO) nanoparticles were successfully prepared via the solution intercalation approach. The thermogravimetric analysis (TGA) revealed that the inclusion of GO nanoparticles into the polymer matrix increased the thermal stability of the coatings. The degree of transparency evaluated by the ultraviolet-visible (UV-Vis) spectroscopy showed that the lowest loading rate of GO (0.5 wt.%) had completely blocked the incoming irradiation, thus resulting in zero percent transmittance. Furthermore, the water contact angle (WCA) measurements revealed that the incorporation of GO nanoparticles and PDMS into the polymer matrix had remarkably enhanced the surface hydrophobicity, exhibiting the highest WCA of 87.55º. In addition, the cross-hatch test (CHT) showed that all the hybrid coatings exhibited excellent surface adhesion behaviour, receiving 4B and 5B ratings respectively. Moreover, the field emission scanning electron microscopy (FESEM) micrographs confirmed that the presence of the functional groups on the GO surface facilitated the chemical functionalization process, which led to excellent dispersibility. The GO composition up to 2 wt.% showed excellent dispersion and uniform distribution of the GO nanoparticles within the polymer matrix. Therefore, the unique features of graphene and its derivatives have emerged as a new class of nanofillers/inhibitors for corrosion protection applications.
  4. Fulltext Anticorrosion, Thermal Degradation, and Hydrophobic Performances of Graphene/TiO2 Nanocomposite Coatings
    Kumar SSA, Mohammed NB, Alduhaish O, Ramesh K, Ramesh S, Khan M, et al.
    Polymers (Basel), 2023 May 23;15(11).
    PMID: 37299227 DOI: 10.3390/polym15112428
    Globally, researchers have devoted consistent efforts to producing excellent coating properties since coating plays an essential role in enhancing electrochemical performance and surface quality. In this study, TiO2 nanoparticles in varying concentrations of 0.5, 1, 2, and 3 wt.% were added into the acrylic-epoxy polymeric matrix with 90:10 wt.% (90A:10E) ratio incorporated with 1 wt.% graphene, to fabricate graphene/TiO2 -based nanocomposite coating systems. Furthermore, the properties of the graphene/TiO2 composites were investigated by Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), ultraviolet-visible (UV-Vis) spectroscopy, water contact angle (WCA) measurements, and cross-hatch test (CHT), respectively. Moreover, the field emission scanning electron microscope (FESEM) and the electrochemical impedance spectroscopy (EIS) tests were conducted to investigate the dispersibility and anticorrosion mechanism of the coatings. The EIS was observed by determining the breakpoint frequencies over a period of 90 days. The results revealed that the TiO2 nanoparticles were successfully decorated on the graphene surface by chemical bonds, which resulted in the graphene/TiO2 nanocomposite coatings exhibiting better dispersibility within the polymeric matrix. The WCA of the graphene/TiO2 coating increased along with the ratio of TiO2 to graphene, achieving the highest CA of 120.85° for 3 wt.% of TiO2. Excellent dispersion and uniform distribution of the TiO2 nanoparticles within the polymer matrix were shown up to 2 wt.% of TiO2 inclusion. Among the coating systems, throughout the immersion time, the graphene/TiO2 (1:1) coating system exhibited the best dispersibility and high impedance modulus values (Z0.01 Hz), exceeding 1010 Ω cm2.
  5. Self-Healing, Flexible and Smart 3D Hydrogel Electrolytes Based on Alginate/PEDOT:PSS for Supercapacitor Applications
    Badawi NM, Bhatia M, Ramesh S, Ramesh K, Kuniyil M, Shaik MR, et al.
    Polymers (Basel), 2023 Jan 22;15(3).
    PMID: 36771872 DOI: 10.3390/polym15030571
    Hydrogel electrolytes for energy storage devices have made great progress, yet they present a major challenge in the assembly of flexible supercapacitors with high ionic conductivity and self-healing properties. Herein, a smart self-healing hydrogel electrolyte based on alginate/poly (3,4-ethylenedioxythiophene):poly(styrenesulfonate) (alginate/PEDOT:PSS)(A/P:P) was prepared, wherein H2SO4 was employed as a polymeric initiator, as well as a source of ions. PEDOT:PSS is a semi-interpenetrating network (IPN) that has been used in recent studies to exhibit quick self-healing properties with the H₂SO₃ additive, which further improves its mechanical strength and self-healing performance. A moderate amount of PEDOT:PSS in the hydrogel (5 mL) was found to significantly improve the ionic conductivity compared to the pure hydrogel of alginate. Interestingly, the alginate/PEDOT:PSS composite hydrogel exhibited an excellent ability to self-heal and repair its original composition within 10 min of cutting. Furthermore, the graphite conductive substrate-based supercapacitor with the alginate/PEDOT:PSS hydrogel electrolyte provided a high specific capacitance of 356 F g-1 at 100 mV/s g-1. The results demonstrate that the A/P:P ratio with 5 mL PEDOT:PSS had a base sheet resistance of 0.9 Ω/square. This work provides a new strategy for designing flexible self-healing hydrogels for application in smart wearable electronics.
  6. Fulltext Creep Behavior of A356 Aluminum Alloy Reinforced with Multi-Walled Carbon Nanotubes by Stir Casting
    Shan L, Tan CY, Shen X, Ramesh S, Kolahchi R, Hajmohammad MH, et al.
    Materials (Basel), 2022 Dec 15;15(24).
    PMID: 36556764 DOI: 10.3390/ma15248959
    Lightweight aluminum alloy components are often used to manufacture a variety of engineering components in many industries. In recent years, researchers have studied the effect of improving the mechanical properties of metal alloys by incorporating nano-carbon into its structure. In this study, the effect of the addition of 0.2, 0.5, and 1 wt% of multi-walled carbon nanotubes (MWCNTs) on the stress-strain behavior and creep phenomenon of an A356 aluminum alloy were studied. The effect of nickel coating on 0.2 wt% MWCNTs was also investigated. Samples were prepared using the stir-casting method. The results revealed that the grain size became finer when MWCNT nano-particulates were introduced. Although the MWCNTs were distributed homogeneously in the A356 matrix, as confirmed by FESEM analysis, there were some agglomerations observed in a specific area with dimensions smaller than 100 nm. Nevertheless, the addition of MWCNTs was found to be beneficial in enhancing the hardness of alloys containing 0.2 wt%, 0.2 wt% nickel-coated, 0.5 wt%, and 1 wt% MWCNTs by 9%, 24%, 32%, and 15%, respectively, as compared with the unreinforced A345 matrix. It was also found that the 0.5 wt% MWCNT-A356 matrix exhibited an improvement in the creep lifetime by more than two orders of magnitude.
  7. Fulltext Hydrothermal synthesis of CuO@MnO2 on nitrogen-doped multiwalled carbon nanotube composite electrodes for supercapacitor applications
    Kakani V, Ramesh S, Yadav HM, Bathula C, Basivi PK, Palem RR, et al.
    Sci Rep, 2022 Sep 20;12(1):12951.
    PMID: 36127493 DOI: 10.1038/s41598-022-16863-3
    Nitrogen-doped multiwalled carbon nanotubes (N-MWCNTs) have been used to fabricate nanostructured materials for various energy devices, such as supercapacitors, sensors, batteries, and electrocatalysts. Nitrogen-doped carbon-based electrodes have been widely used to improve supercapacitor applications via various chemical approaches. Based on previous studies, CuO@MnO2 and CuO@MnO2/N-MWCNT composites were synthesized using a sonication-supported hydrothermal reaction process to evaluate their supercapacitor properties. The structural and morphological properties of the synthesized composite materials were characterized via Raman spectroscopy, XRD, SEM, and SEM-EDX, and the morphological properties of the composite materials were confirmed by the nanostructured composite at the nanometer scale. The CuO@MnO2 and CuO@MnO2/N-MWCNT composite electrodes were fabricated in a three-electrode configuration, and electrochemical analysis was performed via CV, GCD, and EIS. The composite electrodes exhibited the specific capacitance of ~ 184 F g-1 at 0.5 A g-1 in the presence of a 5 M KOH electrolyte for the three-electrode supercapacitor application. Furthermore, it exhibited significantly improved specific capacitances and excellent cycling stability up to 5000 GCD cycles, with a 98.5% capacity retention.
  8. Fulltext Role of Natural Cross Linkers in Resin-Dentin Bond Durability: A Systematic Review and Meta-Analysis
    Anumula L, Ramesh S, Kolaparthi VSK, Kirubakaran R, Karobari MI, Arora S, et al.
    Materials (Basel), 2022 Aug 17;15(16).
    PMID: 36013786 DOI: 10.3390/ma15165650
    BACKGROUND: The role of endogenous Matrix Metallo Proteinases in resin dentin bond deterioration over time has been well documented. The present study aimed to systematically review the literature; in vitro and ex vivo studies that assessed the outcomes of natural cross-linkers for immediate and long-term tensile bond strength were included.

    METHODS: The manuscript search was carried out in six electronic databases-PubMed/MEDLINE, LILACS, SciELO, Cochrane, Web of Science and DOAJ, without publication year limits. Only manuscripts in English (including the translated articles) were selected, and the last search was performed in December 2020. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement was followed.

    RESULTS: From the 128 potentially eligible studies, 48 full-text articles were assessed for eligibility. After eligibility assessment and exclusions, 14 studies were considered for systematic review and seven studies for meta-analysis. Amongst the selected studies for meta-analysis, three had a medium and four had a low risk of bias.

    CONCLUSIONS: It was evidenced by the available data that Proanthocyanidin is the most efficient natural cross-linker to date, in preserving the bond strength even after ageing.

  9. Fulltext Sonication-supported synthesis of cobalt oxide assembled on an N-MWCNT composite for electrochemical supercapacitors via three-electrode configuration
    Nare RK, Ramesh S, Basavi PK, Kakani V, Bathula C, Yadav HM, et al.
    Sci Rep, 2022 Feb 07;12(1):1998.
    PMID: 35132094 DOI: 10.1038/s41598-022-05964-8
    The Co3O4@N-MWCNT composite was synthesized by a sonication-supported thermal reduction process for supercapacitor applications. The structural and morphological properties of the materials were characterized via Raman, XRD, XPS, SEM-EDX, and FE-TEM analysis. The composite electrode was constructed into a three-electrode configuration and examined by using CV, GCD and EIS analysis. The demonstrated electrochemical value of ~ 225 F/g at 0.5 A/g by the electrode made it appropriate for potential use in supercapacitor applications.
  10. Fulltext Revitalizing journal clubs: Millennial perspectives for enhancing student learning and engagement
    Rajhans V, Mohammed CA, Ve RS, Prabhu A
    Educ Health (Abingdon), 2021 7 3;34(1):22-28.
    PMID: 34213440 DOI: 10.4103/efh.EfH_69_20
    Background: Current trends in health professions education are aligned to meet the needs of the millennial learner. The aim of this study was to identify learners' perceptions of an ongoing journal club (JC) activity in the optometry curriculum and evaluate the utility and efficiency of this method in promoting student learning.

    Methods: A qualitative approach with a phenomenological research design was adopted. The perceptions of undergraduate and postgraduate optometry students about JCs were captured using focus group discussions. A narrative thematic analysis was done using the verbatim transcripts and moderator's notes. Results are reported using "consolidated criteria for reporting qualitative research" guidelines.

    Results: A total of 33 optometry students participated in the study. Data analysis revealed three major themes related to (i) The ongoing practice of JC, (ii) student perceptions of JC and its relevance in facilitating student learning, and (iii) suggestions for modification of JC for achieving optimal educational outcomes.

    Discussion: Student feedback indicates that an instructional redesigning of JC is necessary, considering the characteristics and expectations of the current generation of learners and the rapid strides made in the field of educational technology. The recommendations provided are likely to resurrect an age-old approach that still has educational relevance if blended with collaborative learning formats and appropriate technology.

  11. Fulltext Ultrasonication-mediated nitrogen-doped multiwalled carbon nanotubes involving carboxy methylcellulose composite for solid-state supercapacitor applications
    Basivi PK, Ramesh S, Kakani V, Yadav HM, Bathula C, Afsar N, et al.
    Sci Rep, 2021 May 10;11(1):9918.
    PMID: 33972653 DOI: 10.1038/s41598-021-89430-x
    In this study, a novel nanohybrid composite containing nitrogen-doped multiwalled carbon nanotubes/carboxymethylcellulose (N-MWCNT/CMC) was synthesized for supercapacitor applications. The synthesized composite materials were subjected to an ultrasonication-mediated solvothermal hydrothermal reaction. The synthesized nanohybrid composite electrode material was characterized using analytical methods to confirm its structure and morphology. The electrochemical properties of the composite electrode were investigated using cyclic voltammetry (CV), galvanic charge-discharge, and electrochemical impedance spectroscopy (EIS) using a 3 M KOH electrolyte. The fabricated composite material exhibited unique electrochemical properties by delivering a maximum specific capacitance of approximately 274 F g-1 at a current density of 2 A g-1. The composite electrode displayed high cycling stability of 96% after 4000 cycles at 2 A g-1, indicating that it is favorable for supercapacitor applications.
  12. Fulltext Job characteristics of a Malaysian bank's anti-money laundering system and its employees' job satisfaction
    Kannan R, Reddiar Y, Ramakrishnan K, Eastaff MS, Ramesh S
    F1000Res, 2021;10:1052.
    PMID: 36225238 DOI: 10.12688/f1000research.73234.2
    Background: Banks and financial institutions are vulnerable to money laundering (ML) as a result of crime proceeds infiltrating banks in the form of significant cash deposits. Improved financial crime compliance processes and systems enable anti-ML (AML) analysts to devote considerable time and effort to case investigation and process quality work, thereby lowering financial risks by reporting suspicious activity in a timely and effective manner. This study uses Job Characteristics Theory (JCT) to evaluate the AML system through the job satisfaction and motivation of its users. The purpose of this study is to determine how satisfied AML personnel are with their jobs and how motivated they are to work with the system. Methods: This cross-sectional study used JCT to investigate the important elements impacting employee satisfaction with the AML system. The five core dimensions of the job characteristics were measured using a job diagnostic survey. The respondents were employees working in the AML department of a Malaysian bank, and the sample group was chosen using a purposive sampling approach. A total of 100 acceptable replies were gathered and analysed using various statistical approaches. A motivating potential score was generated for each employee based on five main job characteristics. Results: Findings revealed that five core job characteristics, namely, skill diversity, task identity, task importance, autonomy and feedback, positively influence the AML system employees' job satisfaction. However, skill variety and autonomy are found to be low, which are reflected in the poor motivating potential score. Conclusion: This study examined the characteristics of the AML system and its users' job satisfaction. Findings revealed that task significance is the most widely recognised characteristic, followed by feedback and task identity. However, there is a lack of skill variety and autonomy, which must be addressed to improve employee satisfaction with the AML system.
  13. Fulltext Cobalt Oxide Nanograins and Silver Nanoparticles Decorated Fibrous Polyaniline Nanocomposite as Battery-Type Electrode for High Performance Supercapattery
    Iqbal J, Numan A, Omaish Ansari M, Jafer R, Jagadish PR, Bashir S, et al.
    Polymers (Basel), 2020 Nov 27;12(12).
    PMID: 33261072 DOI: 10.3390/polym12122816
    In this study, silver (Ag) and cobalt oxide (Co3O4) decorated polyaniline (PANI) fibers were prepared by the combination of in-situ aniline oxidative polymerization and the hydrothermal methodology. The morphology of the prepared Ag/Co3O4@PANI ternary nanocomposite was studied by scanning electron microscopy and transmission electron microscopy, while the structural studies were carried out by X-ray diffraction and X-ray photoelectron spectroscopy. The morphological characterization revealed fibrous shaped PANI, coated with Ag and Co3O4 nanograins, while the structural studies revealed high purity, good crystallinity, and slight interactions among the constituents of the Ag/Co3O4@PANI ternary nanocomposite. The electrochemical performance studies revealed the enhanced performance of the Ag/Co3O4@PANI nanocomposite due to the synergistic/additional effect of Ag, Co3O4 and PANI compared to pure PANI and Co3O4@PANI. The addition of the Ag and Co3O4 provided an extended site for faradaic reactions leading to the high specific capacity. The Ag/Co3O4@PANI ternary nanocomposite exhibited an excellent specific capacity of 262.62 C g-1 at a scan rate of 3 mV s-1. The maximum energy and power density were found to be 14.01 Wh kg-1 and 165.00 W kg-1, respectively. The cyclic stability of supercapattery (Ag/Co3O4@PANI//activated carbon) consisting of a battery type electrode demonstrated a gradual increase in specific capacity with a continuous charge-discharge cycle until ~1000 cycles, then remained stable until 2500 cycles and later started decreasing, thereby showing the cyclic stability of 121.03% of its initial value after 3500 cycles.
  14. Fulltext Fundamental Concepts of Hydrogels: Synthesis, Properties, and Their Applications
    Bashir S, Hina M, Iqbal J, Rajpar AH, Mujtaba MA, Alghamdi NA, et al.
    Polymers (Basel), 2020 Nov 16;12(11).
    PMID: 33207715 DOI: 10.3390/polym12112702
    In the present review, we focused on the fundamental concepts of hydrogels-classification, the polymers involved, synthesis methods, types of hydrogels, properties, and applications of the hydrogel. Hydrogels can be synthesized from natural polymers, synthetic polymers, polymerizable synthetic monomers, and a combination of natural and synthetic polymers. Synthesis of hydrogels involves physical, chemical, and hybrid bonding. The bonding is formed via different routes, such as solution casting, solution mixing, bulk polymerization, free radical mechanism, radiation method, and interpenetrating network formation. The synthesized hydrogels have significant properties, such as mechanical strength, biocompatibility, biodegradability, swellability, and stimuli sensitivity. These properties are substantial for electrochemical and biomedical applications. Furthermore, this review emphasizes flexible and self-healable hydrogels as electrolytes for energy storage and energy conversion applications. Insufficient adhesiveness (less interfacial interaction) between electrodes and electrolytes and mechanical strength pose serious challenges, such as delamination of the supercapacitors, batteries, and solar cells. Owing to smart and aqueous hydrogels, robust mechanical strength, adhesiveness, stretchability, strain sensitivity, and self-healability are the critical factors that can identify the reliability and robustness of the energy storage and conversion devices. These devices are highly efficient and convenient for smart, light-weight, foldable electronics and modern pollution-free transportation in the current decade.
  15. Fulltext A novel design, analysis and 3D printing of Ti-6Al-4V alloy bio-inspired porous femoral stem
    Mehboob H, Tarlochan F, Mehboob A, Chang SH, Ramesh S, Harun WSW, et al.
    J Mater Sci Mater Med, 2020 Aug 20;31(9):78.
    PMID: 32816091 DOI: 10.1007/s10856-020-06420-7
    The current study is proposing a design envelope for porous Ti-6Al-4V alloy femoral stems to survive under fatigue loads. Numerical computational analysis of these stems with a body-centered-cube (BCC) structure is conducted in ABAQUS. Femoral stems without shell and with various outer dense shell thicknesses (0.5, 1.0, 1.5, and 2 mm) and inner cores (porosities of 90, 77, 63, 47, 30, and 18%) are analyzed. A design space (envelope) is derived by using stem stiffnesses close to that of the femur bone, maximum fatigue stresses of 0.3σys in the porous part, and endurance limits of the dense part of the stems. The Soderberg approach is successfully employed to compute the factor of safety Nf > 1.1. Fully porous stems without dense shells are concluded to fail under fatigue load. It is thus safe to use the porous stems with a shell thickness of 1.5 and 2 mm for all porosities (18-90%), 1 mm shell with 18 and 30% porosities, and 0.5 mm shell with 18% porosity. The reduction in stress shielding was achieved by 28%. Porous stems incorporated BCC structures with dense shells and beads were successfully printed.
  16. Effect of 1-Hexyl-3-Methylimidazolium Iodide Ionic Liquid on Ionic Conductivity and Energy Conversion Efficiency of Solid Polymer Electrolyte-Based Nano-Crystalline Dye-Sensitized Solar Cells
    Khanmirzaei MH, Ramesh S, Ramesh K
    J Nanosci Nanotechnol, 2020 Apr 01;20(4):2423-2429.
    PMID: 31492257 DOI: 10.1166/jnn.2020.17192
    Solid polymer electrolytes (SPEs) were prepared using rice starch as the polymer, sodium iodide (NaI) as the salt and 1-hexyl-3-methylimidazolium iodide (HMII) as the ionic liquid (IL). The solution casting technique was used for preparation of the PEs. The ionic conductivity and temperaturedependent properties of the PEs were measured and all the SPEs were found to follow the Arrhenius thermal activated model. Ionic conductivity increased as the percentage of ILs increased. The SPE containing 20% (wt) of HMII IL showed the highest ionic conductivity of 1.83×10-3 S/cm. Spectral and structural characterization of the PEs were performed by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD), respectively. The results of thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) indicate that the decomposition temperature (Tdc), glass transition temperatures (Tg) and melting points (Tm) shifted when complexation with HMII occurred. The PEs were used to fabricate dye-sensitized solar cells (DSSCs) and the DSSCs were analyzed under a 1-sun simulator. The SPE with the highest ionic conductivity displayed a short circuit current density (Jsc) of 9.07 (mA cm-2), open circuit voltage (Voc) of 0.58 (V), a fill factor (FF) of 0.65 and had the highest energy conversion efficiency of 3.42%.
  17. Biological responses of MC3T3-E1 on calcium carbonate coatings fabricated by hydrothermal reaction on titanium
    Bang LT, Shi R, Bui Duc L, Ramesh S, Shi X, Sugiura Y, et al.
    Biomed Mater, 2020 Jan 08.
    PMID: 31914435 DOI: 10.1088/1748-605X/ab6939
    Titainum (Ti) implants have been successfully used in orthopaedic and dental surgery. However, the poor early bone tissue integration is still a common failure. This could be modulated by improving material bonding or adhesion directly to bone though a surface roughening and/or a bioresorbable and osteoconductive coating. In this study, we report on the biological behavious of the Ti substrate with modified surface roughness and/or bioactive coating. The roughened Ti surface was prepared by acid etching reaction, and the calcium carbonate (CaCO3) coating on the substrates was synthesized by hydrothermal treatment of Ti in calcium citrate complexes. The study demonstrated that surface roughing of Ti alone did not improve the biological reponse of the MC3T3-E1 cells, however, CaCO3 coating on smooth Ti surface increased cell responses, and the affects were further enhanced in combination with Ti surface roughening. Larger cell area, greater cell proliferation and increased bone-like nodule formation were obtained on the CaCO3 coating of the roughened Ti surface. This was also supported by a higher ALP value obtained for the the coatings of roughened Ti surface. The cell behaviours found in the current study support further development of calcium carbonate coatings towards clinical application.
  18. Fulltext Prevalence of visual impairment in school-going children among the rural and urban setups in the Udupi district of Karnataka, India: A cross-sectional study
    Prabhu AV, Ve RS, Talukdar J, Chandrasekaran V
    Oman J Ophthalmol, 2019 10 11;12(3):145-149.
    PMID: 31902987 DOI: 10.4103/ojo.OJO_190_2018
    AIM: The aim of this study is to estimate the prevalence of visual impairment among school-going children in Udupi district, Karnataka.

    MATERIALS AND METHODS: A cross-sectional study across eleven schools from both urban and rural parts of Udupi taluk was conducted to report the magnitude of visual impairment among the schoolchildren. Complex survey design was used in allocating the sample size through stratification and clustering. Totally 1784 schoolchildren between the age groups of 5 and 15 years participated in the study. Presenting visual acuity and objective refraction was measured using computerized logMAR acuity charts and Plusoptix A09 photorefractor, respectively. Manifest ocular deviation or squint was also recorded.

    RESULTS: The mean age of the students was found to be 10.62 ± 2.72 years. The prevalence of visual impairment, i.e., visual acuity worse than or equal to 20/40 in the better eye was found to be 4.32% (95% confidence interval: 3.38%, 5.26%). The prevalence rate was significantly higher among students from urban area (5.6%) compared to those from rural area (3.6%) (P = 0.011).

    CONCLUSION: Visual impairment was found to be 4.32% in the school-going population of Udupi district. Effective and user-friendly devices aided the visual deficit screening including refractive error and squint.

  19. Fulltext Electrolyte selection for supercapacitive devices: a critical review
    Pal B, Yang S, Ramesh S, Thangadurai V, Jose R
    Nanoscale Adv, 2019 Oct 09;1(10):3807-3835.
    PMID: 36132093 DOI: 10.1039/c9na00374f
    Electrolytes are one of the vital constituents of electrochemical energy storage devices and their physical and chemical properties play an important role in these devices' performance, including capacity, power density, rate performance, cyclability and safety. This article reviews the current state of understanding of the electrode-electrolyte interaction in supercapacitors and battery-supercapacitor hybrid devices. The article discusses factors that affect the overall performance of the devices such as the ionic conductivity, mobility, diffusion coefficient, radius of bare and hydrated spheres, ion solvation, viscosity, dielectric constant, electrochemical stability, thermal stability and dispersion interaction. The requirements needed to design better electrolytes and the challenges that still need to be addressed for building better supercapacitive devices for the competitive energy storage market have also been highlighted.
  20. Fulltext Compression after Impact Behaviour and Failure Analysis of Nanosilica-Toughened Thin Epoxy/GFRP Composite Laminates
    Lal LPJ, Ramesh S, Parasuraman S, Natarajan E, Elamvazuthi I
    Materials (Basel), 2019 Sep 20;12(19).
    PMID: 31547117 DOI: 10.3390/ma12193057
    Nanosilica particles were utilized as secondary reinforcement to enhance the strength of the epoxy resin matrix. Thin glass fibre reinforced polymer (GFRP) composite laminates of 3 ± 0.25 mm were developed with E-Glass mats of 610 GSM and LY556 epoxy resin. Nanosilica fillers were mixed with epoxy resin in the order of 0.25, 0.5, 0.75 and 1 wt% through mechanical stirring followed by an ultrasonication method. Thereafter, the damage was induced on toughened laminates through low-velocity drop weight impact tests and the induced damage was assessed through an image analysis tool. The residual compression strength of the impacted laminates was assessed through compression after impact (CAI) experiments. Laminates with nanosilica as secondary reinforcement exhibited enhanced compression strength, stiffness, and damage suppression. Results of Fourier-transform infrared spectroscopy revealed that physical toughening mechanisms enhanced the strength of the nanoparticle-reinforced composite. Failure analysis of the damaged area through scanning electron microscopy (SEM) evidenced the presence of key toughening mechanisms like damage containment through micro-cracks, enhanced fiber-matrix bonding, and load transfer.
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