High level of hydrogen production activity achieved for hydrogenase encapsulated in sol–gel material doped with carbon nanotubes

2010 ◽  
Vol 20 (6) ◽  
pp. 1065 ◽  
Author(s):  
Oleg A. Zadvorny ◽  
Amy M. Barrows ◽  
Nikolay A. Zorin ◽  
John W. Peters ◽  
Timothy E. Elgren
Keyword(s):  
Carbon Nanotubes ◽  
Hydrogen Production ◽  
Sol Gel ◽  
Production Activity ◽  
High Level

scholarly journals Effects of Disruption of Homocitrate Synthase Genes on Nostoc sp. Strain PCC 7120 Photobiological Hydrogen Production and Nitrogenase

2007 ◽  
Vol 73 (23) ◽  
pp. 7562-7570 ◽  
Author(s):  
Hajime Masukawa ◽  
Kazuhito Inoue ◽  
Hidehiro Sakurai
Keyword(s):  
Nitrogen Fixation ◽  
Hydrogen Production ◽  
Double Mutant ◽  
Production Systems ◽  
Combined Nitrogen ◽  
Nitrogen Fixation Activity ◽  
Production Activity ◽  
Homocitrate Synthase ◽  
High Level ◽  
Pcc 7120

ABSTRACT In the case of nitrogenase-based photobiological hydrogen production systems of cyanobacteria, the inactivation of uptake hydrogenase (Hup) leads to significant increases in hydrogen production activity. However, the high-level-activity stage of the Hup mutants lasts only a few tens of hours under air, a circumstance which seems to be caused by sufficient amounts of combined nitrogen supplied by active nitrogenase. The catalytic FeMo cofactor of nitrogenase binds homocitrate, which is required for efficient nitrogen fixation. It was reported previously that the nitrogenase from the homocitrate synthase gene (nifV) disruption mutant of Klebsiella pneumoniae shows decreased nitrogen fixation activity and increased hydrogen production activity under N2. The cyanobacterium Nostoc sp. strain PCC 7120 has two homocitrate synthase genes, nifV1 and nifV2, and with the ΔhupL variant of Nostoc sp. strain PCC 7120 as the parental strain, we have constructed two single mutants, the ΔhupL ΔnifV1 strain (with the hupL and nifV1 genes disrupted) and the ΔhupL ΔnifV2 strain, and a double mutant, the ΔhupL ΔnifV1 ΔnifV2 strain. Diazotrophic growth rates of the two nifV single mutants and the double mutant were decreased moderately and severely, respectively, compared with the rates of the parent ΔhupL strain. The hydrogen production activity of the ΔhupL ΔnifV1 mutant was sustained at higher levels than the activity of the parent ΔhupL strain after about 2 days of combined-nitrogen step down, and the activity in the culture of the former became higher than that in the culture of the latter. The presence of N2 gas inhibited hydrogen production in the ΔhupL ΔnifV1 ΔnifV2 mutant less strongly than in the parent ΔhupL strain and the ΔhupL ΔnifV1 and ΔhupL ΔnifV2 mutants. The alteration of homocitrate synthase activity can be a useful strategy for improving sustained photobiological hydrogen production in cyanobacteria.

scholarly journals Sonochemical/hydration–dehydration synthesis of Pt–TiO2 NPs/decorated carbon nanotubes with enhanced photocatalytic hydrogen production activity

2016 ◽  
Vol 15 (11) ◽  
pp. 1347-1357 ◽  
Author(s):  
Firas H. Abdulrazzak ◽  
Falah H. Hussein ◽  
Ayad F. Alkaim ◽  
Irina Ivanova ◽  
Alexei V. Emeline ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Hydrogen Production ◽  
Photocatalytic Hydrogen Production ◽  
Tio2 Nps ◽  
Production Activity

Modified Pt–TiO2 NPs/decorated carbon nanotubes were synthesized utilizing sonochemical/hydration–dehydration techniques.

Multi-walled Carbon Nanotubes Reinforced into Hollow Fiber by Chitosan Sol-gel for Solid/Liquid Phase Microextraction of NSAIDs from Urine Prior to HPLC-DAD Analysis

2019 ◽  
Vol 20 (5) ◽  
pp. 390-400 ◽  
Author(s):  
Nabil N. AL-Hashimi ◽  
Amjad H. El-Sheikh ◽  
Rania F. Qawariq ◽  
Majed H. Shtaiwi ◽  
Rowan AlEjielat
Keyword(s):  
Carbon Nanotubes ◽  
Liquid Phase ◽  
Hollow Fiber ◽  
Sol Gel ◽  
Liquid Phase Microextraction ◽  
Extraction Device ◽  
Multi Walled Carbon Nanotubes ◽  
Solid Liquid ◽  
Walled Carbon Nanotubes

Background: The efficient analytical method for the analysis of nonsteroidal antiinflammatory drugs (NSAIDs) in a biological fluid is important for determining the toxicological aspects of such long-term used therapies. Methods: In the present work, multi-walled carbon nanotubes reinforced into a hollow fiber by chitosan sol-gel assisted-solid/ liquid phase microextraction (MWCNTs-HF-CA-SPME) method followed by the high-performance liquid chromatography-diode array detection (HPLC–DAD) was developed for the determination of three NSAIDs, ketoprofen, diclofenac, and ibuprofen in human urine samples. MWCNTs with various dimensions were characterized by various analytical techniques. The extraction device was prepared by immobilizing the MWCNTs in the pores of 2.5 cm microtube via chitosan sol-gel assisted technology while the lumen of the microtube was filled with few microliters of 1-octanol with two ends sealed. The extraction device was operated by direct immersion in the sample solution. Results: The main factors influencing the extraction efficiency of the selected NSAIDs have been examined. The method showed good linearity R2 ≥ 0.997 with RSDs from 1.1 to 12.3%. The limits of detection (LODs) were 2.633, 2.035 and 2.386 µg L-1, for ketoprofen, diclofenac, and ibuprofen, respectively. The developed method demonstrated a satisfactory result for the determination of selected drugs in patient urine samples and comparable results against reference methods. Conclusion: The method is simple, sensitive and can be considered as an alternative for clinical laboratory analysis of selected drugs.

scholarly journals Significantly Improved Dielectric Performance of Poly(1-butene)-Based Composite Films via Filling Polydopamine Modified Ba(Zr0.2Ti0.8)O3-Coated Multiwalled Carbon Nanotubes Nanoparticles

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 285
Author(s):  
Lingfei Li ◽  
Qiu Sun ◽  
Xiangqun Chen ◽  
Zhaohua Jiang ◽  
Yongjun Xu
Keyword(s):  
Carbon Nanotubes ◽  
Dielectric Constant ◽  
Energy Storage ◽  
Composite Film ◽  
Multiwalled Carbon Nanotubes ◽  
Sol Gel ◽  
Composite Films ◽  
Weak Electric Field ◽  
Multiwalled Carbon ◽  
Dielectric Performance

The low dielectric constant of the nonpolar polymer poly(1-butene) (PB-1) limits its application as a diaphragm element in energy storage capacitors. In this work, Ba(Zr0.2Ti0.8)O3-coated multiwalled carbon nanotubes (BZT@MWCNTs) were first prepared by using the sol–gel hydrothermal method and then modified with polydopamine (PDA) via noncovalent polymerization. Finally, PB-1 matrix composite films filled with PDA-modified BZT@MWCNTs nanoparticles were fabricated through a solution-casting method. Results indicated that the PDA-modified BZT@MWCNTs had good dispersion and binding force in the PB-1 matrix. These characteristics improved the dielectric and energy storage performances of the films. Specifically, the PDA-modified 10 vol% BZT@ 0.5 vol% MWCNTs/PB-1 composite film exhibited the best dielectric performance. At 1 kHz, the dielectric constant of this film was 25.43, which was 12.7 times that of pure PB-1 films. Moreover, its dielectric loss was 0.0077. Furthermore, under the weak electric field of 210 MV·m−1, the highest energy density of the PDA-modified 10 vol% BZT@ 0.5 vol% MWCNTs/PB-1 composite film was 4.57 J·cm−3, which was over 3.5 times that of PB-1 film (≈1.3 J·cm−3 at 388 MV·m−1).

scholarly journals Biocompatibility Characteristics of Titanium Coated with Multi Walled Carbon Nanotubes—Hydroxyapatite Nanocomposites

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 224 ◽  
Author(s):  
Jung-Eun Park ◽  
Yong-Seok Jang ◽  
Tae-Sung Bae ◽  
Min-Ho Lee
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Sol Gel ◽  
Pure Titanium ◽  
Cell Proliferation And Differentiation ◽  
Transmission Electron ◽  
Proliferation And Differentiation ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Multi walled carbon nanotubes-hydroxyapatite (MWCNTs-HA) with various contents of MWCNTs was synthesized using the sol-gel method. MWCNTs-HA composites were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). HA particles were generated on the surface of MWCNT. Produced MWCNTs-HA nanocomposites were coated on pure titanium (PT). Characteristic of the titanium coated MWCNTs-HA was evaluated by field-emission scanning electron microscopy (FE-SEM) and XRD. The results show that the titanium surface was covered with MWCNTs-HA nanoparticles and MWCNTs help form the crystalized hydroxyapatite. Furthermore, the MWCNTs-HA coated titanium was investigated for in vitro cellular responses. Cell proliferation and differentiation were improved on the surface of MWCNT-HA coated titanium.

One Step Deposition of Sol-Gel Carbon Nanotubes Biocomposite for Reagentless Electrochemical Devices

2012 ◽  
Vol 25 (1) ◽  
pp. 85-93 ◽  
Author(s):  
Veronika Urbanová ◽  
Mathieu Etienne ◽  
Alain Walcarius
Keyword(s):  
Carbon Nanotubes ◽  
Sol Gel ◽  
One Step ◽  
Electrochemical Devices

Nonaqueous synthesis of TiO2–carbon hybrid nanomaterials with enhanced stable photocatalytic hydrogen production activity

2015 ◽  
Vol 3 (18) ◽  
pp. 10060-10068 ◽  
Author(s):  
Yijun Yang ◽  
Ye Yao ◽  
Liu He ◽  
Yeteng Zhong ◽  
Ying Ma ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Hydrogen Production ◽  
Water Splitting ◽  
Hybrid Nanomaterials ◽  
Photocatalytic Hydrogen Production ◽  
Production Activity ◽  
Nonaqueous Synthesis

Enhanced and stable photocatalytic activity upon water splitting was demonstrated in a series of TiO2–carbon hybrid nanomaterials, which were derived from oleylamine wrapped ultrathin TiO2 nanosheets.

Recent trends in carbon nanotubes based prostate cancer therapy: A biomedical hybrid for diagnosis and treatment

2021 ◽  
Vol 18 ◽  
Author(s):  
Raja Murugesan ◽  
Sureshkumar Raman
Keyword(s):  
Prostate Cancer ◽  
Carbon Nanotubes ◽  
Drug Delivery ◽  
Drug Loading ◽  
High Surface ◽  
High Surface Area ◽  
High Capacity ◽  
Chemical Properties ◽  
Diagnosis And Treatment ◽  
High Level

: At present treatment methods for cancer are limited, partially due to the solubility, poor cellular distribution of drug molecules and, the incapability of drugs to annoy the cellular barriers. Carbon nanotubes (CNTs) generally have excellent physio-chemical properties, which include high-level penetration into the cell membrane, high surface area and high capacity of drug loading by in circulating modification with bio-molecules, project them as an appropriate candidate to diagnose and deliver drugs to prostate cancer (PCa). Additionally, the chemically modified CNTs which have excellent 'Biosensing' properties therefore makes it easy for detecting PCa without fluorescent agent and thus targets the particular site of PCa and also, Drug delivery can accomplish a high efficacy, enhanced permeability with less toxic effects. While CNTs have been mainly engaged in cancer treatment, a few studies are focussed on the diagnosis and treatment of PCa. Here, we detailly reviewed the current progress of the CNTs based diagnosis and targeted drug delivery system for managing and curing PCa.

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