Functionalization and Characterization of Multi-Walled Carbon Nanotubes Using Chemical Oxidation Method

Functionalized MWNTs have been of interest for dispersion enhancement in processing or for chemical modifications. Modification of multiwall carbon nanotubes (MWNTs) by ultrasonication with oxidizing acid mixtures is frequently used to functionalize CNTs. In this work, the functionalization process of MWCNTs involves using a mixture of concentrated sulfuric acid and nitric acid (95% H2SO4: 65%HNO3, 3:1 volume ratio), ultrasonicated at 250C for 30min. The results confirmed by Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Scanning Electron Microscopy (SEM). From the FTIR spectrum, the existence of carboxyl group indicates the functionalization of MWCNTs on the outer surface wall. SEM micrographs show the occurrence of surface modification on the MWCNTs structure. Finally, a well dispersed of MWCNTs colloidal was successfully obtained with less MWCNTs structure collapsed

Role Enhancement of ZnO nanoparticles and ZnO/Ag composite for Medical Applications

ZnO nanoparticles assisted with ethanol and 2propanol as capping agent investigated the medical activities of ZnO nanoparticles and ZnO/Ag composite. ZnO nanoparticles were prepared using zinc acetate and silver nitrate as a source of zinc and silver. ZnO/Ag composite also prepared and studied the medical activities. XRD pattern indicates that the structure of ZnO was hexagonal wurtzite with average size 5 nm according to Scherre's formula. The optical band gap of ZnO nanoparticle showed very sensitive for using different capping agent as shown in UV-VIS spectra and also showed blue shift in wavelength corresponding to capping agent. Finally, the antibacterial properties of ZnO and ZnO/Ag composite against Gram-negative and Gram-positive bacteria have been demonstrated using well diffusion method and indentify their antibacterial effects compared with organic antibacterial agents. Keywords: ZnO nanoparticles, ZnO/Ag composite, antibacterial

The origins and spread of domestic horses from the Western Eurasian steppes

This is the final version. Available on open access from Nature Research via the DOI in this recordData availability: All collapsed and paired-end sequence data for samples sequenced in this study are available in compressed fastq format through the European Nucleotide Archive under accession number PRJEB44430, together with rescaled and trimmed bam sequence alignments against both the nuclear and mitochondrial horse reference genomes. Previously published ancient data used in this study are available under accession numbers PRJEB7537, PRJEB10098, PRJEB10854, PRJEB22390 and PRJEB31613, and detailed in Supplementary Table 1. The genomes of ten modern horses, publicly available, were also accessed as indicated in their corresponding original publications57,61,85-87.NOTE: see the published version available via the DOI in this record for the full list of authorsDomestication of horses fundamentally transformed long-range mobility and warfare. However, modern domesticated breeds do not descend from the earliest domestic horse lineage associated with archaeological evidence of bridling, milking and corralling at Botai, Central Asia around 3500 BC. Other longstanding candidate regions for horse domestication, such as Iberia and Anatolia, have also recently been challenged. Thus, the genetic, geographic and temporal origins of modern domestic horses have remained unknown. Here we pinpoint the Western Eurasian steppes, especially the lower Volga-Don region, as the homeland of modern domestic horses. Furthermore, we map the population changes accompanying domestication from 273 ancient horse genomes. This reveals that modern domestic horses ultimately replaced almost all other local populations as they expanded rapidly across Eurasia from about 2000 BC, synchronously with equestrian material culture, including Sintashta spoke-wheeled chariots. We find that equestrianism involved strong selection for critical locomotor and behavioural adaptations at the GSDMC and ZFPM1 genes. Our results reject the commonly held association between horseback riding and the massive expansion of Yamnaya steppe pastoralists into Europe around 3000 BC driving the spread of Indo-European languages. This contrasts with the scenario in Asia where Indo-Iranian languages, chariots and horses spread together, following the early second millennium BC Sintashta culture

Antibacterial activity of Nickel-doped ZnO/MWCNTs hybrid prepared by sol–gel technique

ZnO/MWCNTs and Ni-doped ZnO/MWCNTs hybrid with different concentration of Nickel element was prepared by using sol–gel technique. The produced samples were characterized by using X-ray diffraction analysis (XRD), energy dispersive X-ray spectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR), field-emission scanning electron microscopy (FE-SEM), and UV–vis spectroscopy. The polycrystalline nature with hexagonal wutzite structure of ZnO/MWCNTs and Ni-doped ZnO/MWCNTs hybrid was shown by X-ray diffraction. The hybrid nanostructure's crystalline size increased from 23.73 nm to 34.59 nm. Furthermore, UV-Vis spectroscopy reveals a significant decrease in band gap values from 2.97 eV to 2.01 eV. The FE-SEM analysis, on the other hand, confirms the formation of spherical shapes of ZnO NPs diffused on the surface of MWCNTs. The antibacterial activity showed that the inhibition zone of Ni doped-ZnO/MWCNTs hybrid was 28.5 mm for E. coli and 26.5 mm for S. aureus bacteria, respectively

Experimental investigation of additive free-low-cost vinyl triarylamines based hole transport material for FAPbI3-based perovskite solar cells to enhance efficiency and stability

Perovskite-based solar cells have drawn a lot of attention recently because they possess many desirable qualities, including strong photon absorption, large carrier lifetime, ambipolar transmission, and low exciton binding energy. With continual optimization of each functional layer, particularly the active layer and hole transporting layer, the power conversion efficiency (PCE) of perovskite materials has reached over 25%. Spiro-OMeTAD is a widely utilized hole transport material (HTM) for efficient solar cell operation. To improve conductivity, this material is often doped with additives such as 4-tert-butylpyridine (TBP) or bis(trifluoromethane)sulfonimide lithium salt (Li-TFSI). Unfortunately, these additives can weaken the perovskite layer and reduce device stability. In this work, we enhanced the efficiency as well as stability of formamidinium-based perovskite using additive-free, cost-effective HTM based on vinyl triarylamines developed by the Tokyo chemical industry. We have deposited vinyl triarylamines-based HTM on both FAPbI _3 and MAPbI _3 perovskite. To compare the results, we have deposited traditional additive-based as well as additive free Spiro-OMeTAD on FAPbI _3 perovskite. Results are encouraging as the FAPbI _3 -based device showed a decent power conversion efficiency of 16.86%, which is higher than when the same HTM is deposited on the MAPbI _3 -based device and comparable with doped Spiro-OMeTAD and much higher than undoped Spiro-OMeTAD based HTM deposited on FAPbI _3 perovskite. Enhancement in device performance is attributed to better hole mobility and favourable energy band positioning of vinyl triarylamines based hole transport layer w.r.t FAPbI _3 perovskite. The PCE of a FAPbI _3 -based device using the suggested HTM (SHTM) suffers only a 12% decrease while following the maximum power point for 1800 h in ambient air

Insights into the photovoltaic properties of indium sulfide as an electron transport material in perovskite solar cells

Abstract According to recent reports, planar structure-based organometallic perovskite solar cells (OPSCs) have achieved remarkable power conversion efficiency (PCE), making them very competitive with the more traditional silicon photovoltaics. A complete understanding of OPSCs and their individual parts is still necessary for further enhancement in PCE. In this work, indium sulfide (In2S3)-based planar heterojunction OPSCs were proposed and simulated with the SCAPS (a Solar Cell Capacitance Simulator)-1D programme. Initially, OPSC performance was calibrated with the experimentally fabricated architecture (FTO/In2S3/MAPbI3/Spiro-OMeTAD/Au) to evaluate the optimum parameters of each layer. The numerical calculations showed a significant dependence of PCE on the thickness and defect density of the MAPbI3 absorber material. The results showed that as the perovskite layer thickness increased, the PCE improved gradually but subsequently reached a maximum at thicknesses greater than 500 nm. Moreover, parameters involving the series resistance as well as the shunt resistance were recognized to affect the performance of the OPSC. Most importantly, a champion PCE of over 20% was yielded under the optimistic simulation conditions. Overall, the OPSC performed better between 20 and 30 °C, and its efficiency rapidly decreases above that temperature

Functionalized SWCNTs@Ag–TiO2 nanocomposites induce ROS-mediated apoptosis and autophagy in liver cancer cells

Hybrid nanomaterials with unique physiochemical properties have received a lot of attention, making them attractive for application in different fields like cancer treatment. This study was designed to investigate the combined effects of single-walled carbon nanotubes (SWCNTs) hybridized with silver titanium dioxide composite (SWCNTs@Ag–TiO2). Transmission electron microscopy and field emission scanning electron microscopy images demonstrated the accumulation of SWCNTs with Ag–TiO2 due to an increased main grain size with functionalization to 40 nm. The D and G bands in SWCNTs @Ag–TiO2 shifted to 1,366 and 1,534 cm−1, respectively. SWCNTs@Ag-TiO2 were assessed for their cytotoxicity and autophagy induction in liver cancer cells (Hep-G2) using the lactate dehydrogenase assay, MTT assay, and flow cytometry methods. The results showed that SWCNTs and SWCNTs@Ag–TiO2 exhibited strong anti-cancer activity in vitro against Hep-G2 cells by inducing apoptosis and autophagy in liver cancer cells via controlling the AKT and JNK mitogen-activated protein kinase pathways. The results show that SWCNTs and SWCNTs coated with silver/titanium dioxide (SWCNTs@Ag–TiO2) reduce the cells’ viability and proliferation. It was shown that an excessive amount of reactive oxygen species was a crucial mediator of both the cell death caused by SWCNTs and the cell death caused by SWCNTs combined with Ag–TiO2. Based on these findings, it appears that SWCNTs and SWCNTs@Ag–TiO2 have the potential to be developed as nanotherapeutics for the treatment of liver cancer cells