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Aug 2018 DOI 10.14302/issn.2377-2549.jndc-18-2187
Randjbaran EliasCorresponding author
Aerospace Manufacturing Research Centre (AMRC) Level 7, Tower Block, Faculty of Engineering 43400 UPM, Serdang, Selangor, Malaysia
Among the numerous potential uses of carbon nanotubes (CNT), its utilization to fortify polymers was given careful consideration. This reason can be because of the remarkable firmness, magnificent quality, and the low thickness of CNT. This has given various chances to the innovation of new material frameworks for applications requiring high quality and high modulus. Exact control over preparing factors, including safeguarding flawless CNT structure, uniform scattering of CNT inside the polymer grid, compelling filler– lattice interfacial communications, and arrangement/introduction of polymer chains/CNT, add to the composite strands' unrivalled properties. Consequently, manufacture techniques assume an imperative part in deciding the composite filaments' microstructure and extreme mechanical conduct. The present best in the class of polymer/CNT elite composite filaments, particularly concerning processing– structure– execution, were looked into in this commitment. Future requirements for material by configuration approaches for handling these nano-composite frameworks were likewise examined.
Sep 2017 DOI 10.14302/issn.2832-4048.jsm-17-1621
A. Koryak YuriCorresponding author
SSC of the Russian Federation − Institute of Biomedical Problems of the RAS
The effects of long-term space flight on human triceps surae (TS) muscle function and electromechanical delay (EMD) have been investigated. Voluntary and electrically evoked contractions of the TS were obtained from 7 male cosmonauts 30 days before and 3 days after landing. For all cosmonauts the isometric maximal voluntary contraction was reduced by 41.7 % (p < 0.01), whereas the electrically evoked maximal tetanic contraction force (Po) was found to decrease by 25.6 % (p < 0.05). Force deficit increased by 50 % (p < 0.001). This suggests that most of the force loss is due to a reduction in motor drive (motor control). The decrease in Po was associated with a significant increase of the corresponding maximal rates of tension development (43.7 %). The twitch tension (Pt) was not significantly changed and the Pt/Po ratio was increased by 46.7 % (p < 0.05) after space mission. The twitch time-to-peak tension of the TS increased by 7.7 %, but half-relaxation time decreased by 20.6 %. Force-velocity properties of the TS calculated according to a relative scale of voluntary contraction development significantly decreased. The calculations of the same properties of electrically evoked contraction development did not differ substantially from the initial physiological state. Total reaction time (TRT), pre-motor time (PMR) and motor time or EMD were determined. In response to a supramaximal single electrical pulses applied to the tibial nerve, the latent period between the M-wave and Рt beginning was determined. The voluntary contraction EMD increased by 34.1 %; but PMR and TRT decreased by 19.0 and 14.1 %, respectively. The EMD of electrically evoked contraction did not significantly change. Thus, the comparison of the mechanical alterations recorded during voluntary contractions and in contractions evoked by electrical stimulation of the motor nerve, suggests that weightlessness not only modifies the peripheral processes associated with contractions, but also changes central and/or neural command of the contraction.
Jul 2021 DOI 10.14302/issn.2576-6694.jbbs-21-3819
Jana SnehasisCorresponding author
Trivedi Science Research Laboratory Pvt. Ltd., Thane (W), Maharashtra, India.
The present study aimed to evaluate the effect of the Trivedi Effect®- Biofield Energy Treated/Blessed Test formulation/item (TI) composed of minerals (magnesium, zinc, copper, calcium, selenium, and iron), vitamins (ascorbic acid, pyridoxine HCl, alpha tocopherol, cyanocobalamin, and cholecalciferol), Panax ginseng extract, CBD isolates, and β-carotene on elasticity of skin, heart, muscle, and neuronal cells in the H9C2 (rat cardiomyocytes), C2C12 (mouse myoblast cells), HaCaT (human keratinocytes), and SH-SY5Y (human neuroblastoma cells) cell line in DMEM medium. The test formulation constituents were divided into two parts; one section was defined as untreated test formulation (UT), while the other portion of test formulation received Biofield Energy Healing/Blessing Treatment (BT) by a renowned Biofield Energy Healer, Mr. Mahendra Kumar Trivedi. The test items were treated with Biofield Energy Healing/Blessing Treatment and divided as Biofield Energy Treated/Blessed (BT) and untreated (UT) test items. MTT data showed that the test formulation in various concentrations was found as safe and nontoxic in the tested concentrations with viability range from 73% to 307%. Young’s modulus (YM) is a measure of cell stiffness, a decrease in YM value indicates increase elasticity of the cells and vice-versa. YM in H9C2 cells were decreased by 9.6% and 66.1% in the BT-DMEM + UT-TI group at 0.1 and 1 µg/mL respectively, as compared with untreated test group. However, C2C21 cells showed increased YM by 443.9% at 1 µg/mL in the UT-DMEM + BT-TI group, while 869.6% increased YM in the BT-DMEM + UT-TI group at 1 µg/mL as compared with untreated test group. However, 314% increased YM was reported in the BT-DMEM + BT-TI group at 1 µg/mL as compared with the untreated test group. However, the value of YM was significantly decreased in the HaCaT cell line by 247.7% (at 1 µg/mL), 225.8% (at 0.1 µg/mL), and 97.9% (at 1 µg/mL) in the UT-DMEM + BT-TI, BT-DMEM + UT-TI, and BT-DMEM + BT-TI group respectively, as compared with the untreated group. In addition, YM was significantly decreased in the SH-SY5Y cell line by 92.6%, 18.1%, and 26.6% at 1 µg/mL in the UT-DMEM + BT-TI, BT-DMEM + UT-TI, and BT-DMEM + BT-TI group respectively, as compared with the untreated group. Overall, the results showed the significant decreased YM among the SH-SY5Y, HaCaT, and H9C2 cells, while it was increased in the C2C21 cell line. Thus, the mechanical properties of cells such as cellular function, including shape, motility, differentiation, division, and adhesion to its surrounding extracellular matrix were improved. Overall, it can be useful in many disease progressions with improved cellular elasticity and its associated complications/symptoms.
Apr 2020 DOI 10.14302/issn.2689-2855.jan-20-3244
Bendjemil BadisCorresponding author
DGM, FST, University of 8 Mai 1945 of Guelma, 24000 Guelma, Algeria
Nanocomposites are worn resistant materials used in cutting tool applications. The materials are composed of ultrafine powder hard phase grains surrounded by a tough binder phase carbon nanotubes (Mo2C)1-x–(TiC)x (2≤x≤4)//1Wt% SWCNTs. Composite bicarbide Mo2C-TiC was rapidly synthesised and simultaneously consolidated by field activated sintering technique (spark plasma sintering) at which the extensive volume expansion occurred as a function of the volumic fraction from 20 to 40 vol.% of TiC powders and 1 Wt.% of SWCNTs was reinforcement of the NCMC’s. The sintered powder mixture was examined by XRD patterns, the morphology of the obtained phase was observed by SEM and the phase compositions in different regions were analyzed by EDX. The composites were processed using Field Activated Sintering Technique, spark plasma sintering (SPS) at temperatures in the range of 1700-1800°C with addicting of SWCNTs. The effects of SWCNTs addition on phases morphology, microstructure hardness and fracture toughness of the nanocomposite were investigated. The best product contained 1.0 Wt% SWCNTs from (Mo2C)1-x–(TiC)x , x= 0.2 which was sintered at 1700°C, 70 MPa for 10 min, M0.8T0.2/ 1 Wt% SWCNTs exhibit a better density, highest hardness and good ductility. Relative densification was achieved 99.5 % from the theoretical and good mechanical properties like hardness and fracture toughness (KIC=5.6 Mpa m1/2) are improved. The results were confirmed using Raman scattering resonant spectroscopy.
Mar 2020 DOI 10.14302/issn.2689-2855.jan-20-3263
Bendjemil BadisCorresponding author
DGM, FST, University of 8 Mai 1945 of Guelma, 24000 Guelma, Algeria
Nanocomposites are worn resistant materials used in cutting tool applications. The materials are composed of ultrafine powder hard phase grains surrounded by a tough binder phase carbon nanotubes (Mo2C)1-x–(TiC)x (2≤x≤4)//1Wt% SWCNTs. Composite bicarbide Mo2C-TiC was rapidly synthesised and simultaneously consolidated by field activated sintering technique (spark plasma sintering) at which the extensive volume expansion occurred as a function of the volumic fraction from 20 to 40 vol.% of TiC powders and 1 Wt.% of SWCNTs was reinforcement of the NCMC’s. The sintered powder mixture was examined by XRD patterns, the morphology of the obtained phase was observed by SEM and the phase compositions in different regions were analyzed by EDX. The composites were processed using Field Activated Sintering Technique, spark plasma sintering (SPS) at temperatures in the range of 1700-1800°C with addicting of SWCNTs. The effects of SWCNTs addition on phases morphology, microstructure hardness and fracture toughness of the nanocomposite were investigated. The best product contained 1.0 Wt% SWCNTs from (Mo2C)1-x–(TiC)x , x= 0.2 which was sintered at 1700°C, 70 MPa for 10 min, M0.8T0.2/ 1 Wt% SWCNTs exhibit a better density, highest hardness and good ductility. Relative densification was achieved 99.5 % from the theoretical and good mechanical properties like hardness and fracture toughness (KIC=5.6 Mpa m1/2) are improved. The results were confirmed using Raman scattering resonant spectroscopy.
Aug 2017 DOI 10.14302/issn.2470-5020.jnrt-17-1487
Alipour Ataabadi YasaminCorresponding author
Faculty of Physical Education and Sports Sciences, Department of Sports Biomechanics, kharazmi university, Tehran
The global popularity of soccer has led to widespread tendency towards this sport. Because of the convenience of using artificial surfaces, the rapid growth of using these surfaces led to concerns about the declining performance of the players. The aim of this comprehensive review is to study the difference between the performance of players on different playing surfaces and the risk factors for use of artificial turf compared to natural grass. A literature search of valid scientific databases such as Science Direct, PubMed and Jstor by searching keywords was performed. In total, more than 6,000 articles were retrieved. After the preliminary selection process, the final analysis was performed on a total of 76 articles. Results: Mechanical properties of artificial grass have a significant effect on the average time of sprinting, the best time of sprinting and maximum speed. The numbers of sliding tackles on artificial turf were lower compared to natural grass. Artificial turfs exposed hardness, elasticity and high friction. The characteristics of artificial grass have changed over time and increased the probability of injuries. There was no significant difference between the overall risks of acute injuries in soccer players performing on artificial turf compared to natural grass. The amateur, young and female soccer players had rated lower injuries on artificial grass. But the rate of injuries in elite soccer players were higher on artificial grass and hence they are not found of playing on such playing surfaces.