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Klebsiella pneumoniae is a gram-negative bacillus of the Enterobacteriaceae family. Despite being part of the natural human microflora, this is an opportunistic pathogen and a major cause of nosocomial infections. The increased emergence of multidrug resistance in Klebsiella pneumoniae has limited the treatment options for this bacterium. Carbon nanotubes (CNT), by improving the stability and solubulity of drugs, could increase the effectiveness of drugs for treatment. The aim of this study is to investigate the antibacterial effect of nanofluid containing functionalized multi-walled carbon nanotubes (f-CNT-NF) on Klebsiella pneumoniae isolated from clinical specimens. For the strain confirmation, biochemical ,API20E kit, and additional differential tests were performed, and antibiotic susceptibility test was performed by the disk diffusion method. The studied strain showed a resistance to all antibiotics such as cefepime.The minimum inhibitory concentration (MIC) was determined using the antibiotic micro dilution method. The MIC was determined in five effect modes including antibiotic (Ab), nanofluid containing functionalized multi-walled carbon nanotubes (f-CNT-NF) , nanofluid containing multi-walled carbon nanotubes (CNT-NF) ,Ab in combination with f-CNT-NF and Ab with CNT-NF. Nevertheless the individual effects of 10 µg mL^-1 cefepime or 80 µg of nanofluid with f-CNT-NF did not inhibit the growth of the bacteria, but the co-administration of 10 µg mL^-1 cefepime with 80 µg of the f-CNT-NF could inhibit the bacteria`s growth. It was concluded that f-CNT-NF could be more effective in drug delivery at lower concentrations than the free state, which could be used as a tool for optimal drug delivery.

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Many studies have been conducted on the absorption and protection of electromagnetic waves to reduce the harmful effects of electromagnetic radiation on the environment. High conductivity shields are used to prevent the penetration of electromagnetic waves. A convenient and useful method of obtaining electromagnetic shielding materials is the addition of conductive carbon materials including carbon fibers, carbon filaments, and carbon nanotubes. Carbon nanotubes can easily form a conductive network within a material field due to their two-dimensional tubular structures and high conductivity, which results in a high electrical permeability ambience. Therefore, the increase in dielectric losses results in reflection losses of electromagnetic waves. Thus, the presence of carbon nanotubes in the adsorbent improves the absorption properties of electromagnetic waves.
In this study, the electromagnetic wave absorbing properties of multi-walled carbon nanotubes (MWCNT) functionalization with carboxyl (-COOH) group /cement composites with different shapes; chiral, zigzag and armchair were studied by short circuit of the waveguide and matched load methods. The influence of the MWCNT shape and sample thickness on the electromagnetic wave absorbing properties were discussed and analyzed in the frequency range of 8–12 GHz by a short circuit of the waveguide and matched load methods. The samples were prepared in two thicknesses of 3 and 6 mm, and the amount of nanotubes added was 0.1%wt. The addition of 0.1 wt.% MWCNT greatly enhances the absorption performance of the cement mortar in the frequency range of  8–10 GHz. With the increase of thickness from 3 mm to 6 mm, the frequency bandwidths of the reflection loss for MWCNT/cement composites increases but the number of peaks decreases.  By comparing the results of electromagnetic wave absorbing of the samples with two different methods are deduced that in the samples with a thickness of 3 mm, the absorbing of waves by matched load method is better than short circuit method without matched load. However, in samples with a thickness of 6 mm, there is not much different. Also, the electromagnetic wave absorbing of the composite samples with a thickness of 3 mm performed better by short circuit method at frequencies below 10.5 GHz, while the composite samples had better absorbing in the matched load method at frequencies greater than 10.5 GHz. In addition, the electromagnetic wave absorbing of the composite samples with a thickness of 6 mm show better results by short circuit method at lower frequencies and by matched load method at higher frequencies. Moreover, the absorption behavior of the chiral sample with thickness 6 mm differs from the other two samples because the chiral nanotubes are asymmetric and zigzag and armchair nanotubes are symmetric. Furthermore, the structural analysis and surface morphology of MWCNT/cement composites with different shapes have been explored using the scanning electron microscope (SEM) technique. Scanning electron microscope images of MWCNT/cement composites show dispersion of nanotubes in composite. Connecting of nanotubes and cement leads to reduction of porosity and formation of regional conductive network. As a result, the electrical conductivity is increased and the electromagnetic field in the network is attenuated.

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This study developed carboxylated multi-walled carbon nanotubes (MWCNTs-COOH) as sorbents to extract flavonoids from grapefruit peel. The impact of solution pH and desorption conditions on extraction efficiency was investigated. In addition, Fourier transforms infrared spectroscopy, thermogravimetry, UV-visible spectroscopy, and scanning electron microscopy were used to characterize the carbon nanotubes. After five cycles, the desorption percentage of flavonoids was 82.7%. HPLC analysis indicated that naringin was the dominant flavonoid in the grapefruit extracts, followed by rutin and quercetin. Insights into the adsorption mechanism of naringin to the MWCNT-COOH were obtained using the Freundlich isotherm equation to model the results. The carbon nanotubes developed in this study offer a cost-effective and straightforward method of extracting value-added functional ingredients from food waste, thereby improving the sustainability and economic viability of the food supply.