scholarly journals Investigating of a wide range of concentrations of multi-walled carbon nanotubes on germination and growth of castor seeds (Ricinus communis L.)

2017 ◽  
Vol 57 (3) ◽  
pp. 228-236 ◽  
Author(s):  
Zahra Fathi ◽  
Ramazan-Ali Khavari Nejad ◽  
Homa Mahmoodzadeh ◽  
Taher Nejad Satari
Keyword(s):  
Carbon Nanotubes ◽  
Ricinus Communis ◽  
Germination Rate ◽  
Dry Weight ◽  
Seedling Vigor ◽  
Vigor Index ◽  
Wide Range ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Germination And Growth

Abstract Carbon nanotubes act as regulators of plant germination and growth and are able to change the morphology and physiology of plant cells. The castor plant (Ricinus communis L.) belongs to the Euphorbiaceae family and is a very important medicinal plant. The aim of this study was to investigate the effect of 10 different concentrations of multi-walled carbon nanotubes (MWCNTs) (2, 5, 10, 20, 50, 75, 100, 125, 250 and 500 μg · ml−1) alongside the control under laboratory conditions on the germination and growth of castor seedlings. The results demonstrated that the maximum percentage of germination (96.7%) and relative germination percentage (100%) were found in the concentrations of 50 and 100 μg · ml−1, respectively, and the highest germination rate (53.3%) and the mean germination time (4.6 days) was seen in the concentration of 75 μg · ml−1. However, no statistically significant differences were found between the different concentrations in any of the germination factors. In the concentration of 100 μg · ml−1, there was a significant increase in the seedling vigor index I (400) when compared with the concentrations of 5 and 10 μg · ml−1. The maximum seedling vigor index II (11.3) was found in the concentration of 100 μg · ml−1 and was significantly different from the control and all applied concentrations. The length of radicle in the 100 and 125 μg · ml−1 had a significant increase when compared with the control and the concentrations of 10 and 50 μg · ml−1. The maximum seedling length (4.6 cm) was seen in the concentration of 100 μg · ml−1 where there was a significant increase with 10 μg · ml−1. Moreover, in the 100 μg · ml−1 concentration, the largest number of rootlets (8.6) was seen and when compared with the control and concentrations of 5, 10 and 50 μg · ml−1, there was a statistically significant increase. The maximum wet weight (0.3 g) and dry weight (0.1 g) of seedlings were obtained in the concentration of 100 μg · ml−1 and when compared with the control, there was a significant increase. It was found that in all factors related to the growth of seedlings, the concentrations of 10 and 50 MWCNTs had an inhibitory effect on the response index. The MWCNTs concentration of 100 μg · ml−1 was considered as the optimum concentration in the growth stage of castor seedlings.

scholarly journals A New Method for Dispersing Pristine Carbon Nanotubes Using Regularly Arranged S-Layer Proteins

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1346
Author(s):  
Andreas Breitwieser ◽  
Uwe B. Sleytr ◽  
Dietmar Pum
Keyword(s):  
Carbon Nanotubes ◽  
Covalent Modification ◽  
Silica Layer ◽  
Medical Sciences ◽  
Lysinibacillus Sphaericus ◽  
Wide Range ◽  
Catalytic Sites ◽  
Multi Walled Carbon Nanotubes ◽  
Pristine Mwnts ◽  
Walled Carbon Nanotubes

Homogeneous and stable dispersions of functionalized carbon nanotubes (CNTs) in aqueous solutions are imperative for a wide range of applications, especially in life and medical sciences. Various covalent and non-covalent approaches were published to separate the bundles into individual tubes. In this context, this work demonstrates the non-covalent modification and dispersion of pristine multi-walled carbon nanotubes (MWNTs) using two S-layer proteins, namely, SbpA from Lysinibacillus sphaericus CCM2177 and SbsB from Geobacillus stearothermophilus PV72/p2. Both the S-layer proteins coated the MWNTs completely. Furthermore, it was shown that SbpA can form caps at the ends of MWNTs. Reassembly experiments involving a mixture of both S-layer proteins in the same solution showed that the MWNTs were primarily coated with SbsB, whereas SbpA formed self-assembled layers. The dispersibility of the pristine nanotubes coated with SbpA was determined by zeta potential measurements (−24.4 +/− 0.6 mV, pH = 7). Finally, the SbpA-coated MWNTs were silicified with tetramethoxysilane (TMOS) using a mild biogenic approach. As expected, the thickness of the silica layer could be controlled by the reaction time and was 6.3 +/− 1.25 nm after 5 min and 25.0 +/− 5.9 nm after 15 min. Since S-layer proteins have already demonstrated their capability to bind (bio)molecules in dense packing or to act as catalytic sites in biomineralization processes, the successful coating of pristine MWNTs has great potential in the development of new materials, such as biosensor architectures.

scholarly journals Fabrication and Characterization of Polylactic Acid Electrospun Scaffolds Modified with Multi-Walled Carbon Nanotubes and Hydroxyapatite Nanoparticles

Biomimetics ◽  
2020 ◽  
Vol 5 (3) ◽  
pp. 43
Author(s):  
Athanasios Kotrotsos ◽  
Prokopis Yiallouros ◽  
Vassilis Kostopoulos
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Polylactic Acid ◽  
Physical And Mechanical Properties ◽  
Polymeric Materials ◽  
Cost Effective ◽  
Electrospinning Process ◽  
Wide Range ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

The solution electrospinning process (SEP) is a cost-effective technique in which a wide range of polymeric materials can be electrospun. Electrospun materials can also be easily modified during the solution preparation process (prior SEP). Based on this, the aim of the current work is the fabrication and nanomodification of scaffolds using SEP, and the investigation of their porosity and physical and mechanical properties. In this study, polylactic acid (PLA) was selected for scaffold fabrication, and further modified with multi-walled carbon nanotubes (MWCNTs) and hydroxyapatite (HAP) nanoparticles. After fabrication, porosity calculation and physical and mechanical characterization for all scaffold types were conducted. More precisely, the morphology of the fibers (in terms of fiber diameter), the surface properties (in terms of contact angle) and the mechanical properties under the tensile mode of the fabricated scaffolds have been investigated and further compared against pristine PLA scaffolds (without nanofillers). Finally, the scaffold with the optimal properties was proposed as the candidate material for potential future cell culturing.

scholarly journals A workflow to investigate the impacts of weathered multi-walled carbon nanotubes to the mud snail Lymnaea stagnalis

2021 ◽  
Author(s):  
Katrin Weise ◽  
Thomas Kurth ◽  
Irina Politowski ◽  
Carola Winkelmann ◽  
Andreas Schäffer ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electron Microscope ◽  
Lymnaea Stagnalis ◽  
Physiological State ◽  
Model Organism ◽  
Dry Weight ◽  
Isotopic Labeling ◽  
Mud Snail ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Abstract Although the development and application of nanomaterials is a growing industry, little data is available on the ecotoxicological effects on aquatic organisms. Therefore, we set up a workflow to address the potential uptake of weathered multi-walled carbon nanotubes (wMWCNTs) by a model organism, the pulmonary mud snail Lymnaea stagnalis (L. stagnalis), which plays an important role in the food web. It represents a suitable organism for this approach because as a grazer it potentially ingests large amounts of sedimented wMWCNTs. As food source for L. stagnalis, benthic biofilm was investigated by the use of a transmission electron microscope (TEM) and a scanning electron microscope (SEM) after exposure with wMWCNTs. In addition, isotopic labeling was applied with 14C-wMWCNTs (0.1 mg/L) to quantify fate, behavior, and enrichment of 14C-wMWCNTs in benthic biofilm and in L. stagnalis. Enrichment in benthic biofilm amounted to 529.0 µg wMWCNTs/g dry weight and in L. stagnalis to 79.6 µg wMWCNTs/g dry weight. A bioconcentration factor (BCF) for L. stagnalis was calculated (3500 L/kg). We demonstrate the accumulation of wMWCNTs (10 mg/L) in the digestive tract of L. stagnalis in an effect study. Moreover, the physiological markers glycogen and triglycerides as indicators for the physiological state, as well as the RNA/DNA ratio as growth indicator, were examined. No significant differences between exposed and control animals were analyzed for glycogen and triglycerides after 24 days of exposure, but a decreasing trend is recognizable for triglycerides. In contrast, the significant reduction in the RNA/DNA ratio of L. stagnalis indicated an inhibition of growth with a following recovery after depuration. The described workflow enables a comprehensive determination of the fate and the behavior of wMWCNTs specifically and in general all kinds of CNTs in the aquatic environment and therefore contributes to a holistic risk assessment of wMWCNTs.

scholarly journals Amplitude modulator of Multi-walled Carbon nanotubes/Chitin in the C-band region

2021 ◽  
Vol 2075 (1) ◽  
pp. 012005
Author(s):  
N H Muhamad Apandi ◽  
H Ahmad ◽  
M H Ibrahim ◽  
F Ahmad
Keyword(s):  
Carbon Nanotubes ◽  
Regression Line ◽  
Optical Signal ◽  
Linear Region ◽  
Peak Intensity ◽  
Wide Range ◽  
All Optical ◽  
Multi Walled Carbon Nanotubes ◽  
Amplitude Modulator ◽  
Walled Carbon Nanotubes

Abstract In ultrafast all-optical signal processing, the all-optical method is crucial, and all-fiber technique offers a wide range of applications in optical communications. This study investigated the amplitude modulation using multi-walled carbon nanotubes (MWCNTs) embedded into chitin as saturable absorber (SA). The MWCNTs-chitin SA is fabricate using a liquid phase exfoliation method to reduce complexity and produce an excellent material quality. In this paper, an optical amplitude modulator produced a linear region with a regression line of the peak intensity at pump power range from 17.92 mW to 67.92 mW with modulation efficiency of 0.50 dB/mW.

scholarly journals Substrate moisture and temperature in Cajanus cajan (L.) Millspaugh germination

2017 ◽  
Vol 38 (4Supl1) ◽  
pp. 2375
Author(s):  
Edlânia Maria de Souza ◽  
Edna Ursulino Alves ◽  
Maria Lúcia Maurício da Silva ◽  
Luciana Rodrigues de Araújo ◽  
Maria Das Mercês Serafim dos Santos Neta
Keyword(s):  
Seed Germination ◽  
Cajanus Cajan ◽  
Germination Rate ◽  
Dry Weight ◽  
Mineral Nutrient ◽  
Seedling Vigor ◽  
Local Climate ◽  
Climate Conditions ◽  
Wide Range ◽  
Water Volumes

Cajanus cajan (L.) Millspaugh, a member of the Fabaceae, is commonly known as feijão-guandu. It was introduced into Brazil because it readily adapts to local climate conditions and tolerates a wide range of water and mineral nutrient levels. The objective of this study was to determine the substrate temperatures and water volumes that are conducive to feijão-guandu seed germination and seedling vigor. The experiment was conducted at the Laboratory of Seed Analysis of the Centre of Agricultural Sciences, Federal University of Paraíba, Areia, PB, Brazil. Seed germination was tested using paper towel rolls moistened with volumes of water equivalent to 2, 2.5, 3, 3.5, and 4 times the dry mass of the substrate. Variable temperatures in the range of 20 °C to 30 °C and constant temperatures of 25 °C, 30 °C, and 35 °C were used. The experimental design was completely randomized. The variables analyzed were water content, percent germination, first germination count, germination rate index, and seedling root and shoot lengths and dry weights. Increasing the volume of water used to moisten the substrate hindered feijão-guandu germination at all temperatures. It was determined that moistening the substrate with water volumes equivalent to 2.8 and 3.5 times the substrate dry weight at 30 °C and 35 °C, respectively, were the ideal conditions for evaluating feijão-guandu seed germination and seedling vigor.

Dielectrophoretic Assembly of Organized Carbon Nanotubes and Thin Films

2010 ◽  
Author(s):  
Pengfei Li ◽  
Wei Xue
Keyword(s):  
Thin Films ◽  
Carbon Nanotubes ◽  
Nanoelectromechanical Systems ◽  
Experimental Conditions ◽  
Energy Devices ◽  
Nanotube Bundles ◽  
Wide Range ◽  
Multi Walled Carbon Nanotubes ◽  
Controlled Deposition ◽  
Walled Carbon Nanotubes

In this paper, we investigate the dielectrophoretic assembly of organized carbon nanotube (CNT) and CNT thin films. Both single-walled carbon nanotubes (SWNTs) and multi-walled carbon nanotubes (MWNTs) are employed in our experiments. Electrodes with “teeth”-like patterns are fabricated to study the influence of electrode width on CNT deposition and alignment. The entire fabrication process is compatible with optical lithography based techniques. Therefore, the fabrication cost is low and the resulting devices are inexpensive. SWNT and MWNT solutions are prepared with different concentrations. The alignment of SWNT/MWNT thin films and small bundles are achieved under the optimized experimental conditions. The electrical properties of these samples are characterized. The results demonstrate that the controlled deposition of CNT thin films using dielectrophoresis is highly repeatable. The alignment of small nanotube bundles can only be achieved using narrow electrodes and low-concentration solutions. Our investigation shows that it is possible to deposit a controllable amount of CNTs in desirable locations using dielectrophoresis. This research has the potential to enable the development of practical and inexpensive CNT devices that can be used in a wide range of applications: nanoelectronics, nano-bioelectronics, nanoelectromechanical systems (NEMS), and energy devices.

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