Recent Advances in the Applications of Nanotechnology and Nanomaterials in the Petroleum Industry: A Descriptive Review

Nanotechnology applications are rapidly expanding in various fields because of its unique qualities, such as a large surface area. Also, the synthetic changes can be utilized to alter nanomaterial to fit into specialized necessities. From the last decade there is a tremendous increase in the utilization of nanotechnology and nanomaterials in the petroleum industry. The current review's main objective is to summarize numerous nanoparticle applications in the field of petroleum, bio-fuel formation, and clean-up treatments of oil spill-related issues with their existing challenges that may help improve further research.     

Heterogeneous domains and membrane permeability in phosphatidylcholine-phosphatidic acid rigid vesicles as a function of pH and lipid chain mismatch

Heterogeneous lipid membranes tuned by pH were evaluated at 37 degrees C in the form of PEGylated vesicles composed of lipid pairs with dipalmitoyl ( n = 16) and distearoyl ( n = 18) chain lengths. One lipid type was chosen to have the titratable moiety phosphatidic acid on its headgroup, and the other lipid type was chosen to have a phosphatidylcholine headgroup. The effect of pH on the formation of lipid heterogeneities and on membrane permeability was studied on vesicles composed of lipid pairs with matching and nonmatching chain lengths. The formation of lipid heterogeneities increases with decreasing pH in membranes composed of lipid pairs with either matching or nonmatching chain lengths. Increased permeability with decreasing pH was exhibited only by membranes composed of lipid pairs with nonmatching chain lengths. Permeability rates correlate strongly with the predicted extent of interfacial boundaries of heterogeneities, suggesting defective packing among nonmatching acyl chains of lipids. In heterogeneous mixtures with one lipid type in the fluid state ( n = 12), the dependence of membrane permeability on pH is weaker. In the presence of serum proteins, PEGylated gel-phase vesicles containing lipid pairs with nonmatching chain lengths exhibit faster release rates with decreasing pH compared to measured release rates in phosphate buffer, suggesting a second mechanism of formation of separated phases. PEGylated vesicles composed of lipid pairs with nonmatching chain lengths labeled with internalizing anti-HER2/neu antibodies that target overexpressed antigens on the surface of SKOV3-NMP2 ovarian cancer cells exhibit specific cancer cell targeting, followed by extensive internalization (more than 84% of bound vesicles) and fast release of contents intracellularly. These PEGylated vesicles composed of rigid membranes for long blood circulation times that exhibit pH-dependent release of contents intracellularly could become potent drug delivery carriers for the targeted therapy of solid tumors.     

Mathematical modelling of enzyme kinetics reaction mechanisms and analytical solutions of non-linear reaction equations

The boundary value problem in basic enzyme reactions is formulated and approximate expressions for substrate and product concentrations are presented. He’s variational iteration method is used to give approximate and analytical solutions of non-linear reaction equations containing a non-linear term related to enzymatic reaction. The relevant analytical solutions for the substrate, enzyme, substrate-enzyme and product concentration profiles are discussed in terms of dimensionless reaction diffusion parameters K, λ and e{varepsilon}.     

Gamma irradiation induced enhancement of phenylalanine ammonia-lyase (PAL) and antioxidant activity in peach (Prunus persica Bausch,Cv. Elberta)

Effect of medium dose gamma irradiation on PAL and antioxidant activity of peach fruit was investigated. Peach fruit after harvest at commercial maturity was irradiated in the dose range 1.0–2.0 kGy, stored under refrigerated conditions (3±1 °C, RH 80%) and evaluated at intervals of 7 days. The antioxidant activity as determined by DPPH and FRAP methods revealed significant (p≤0.05) increase particularly in the dose range 1.6–2.0 kGy. During storage, maximum increase in both PAL and antioxidant activity was observed after 21 days. Positive correlation (r=0.75) existed between antioxidant activity and total phenols. EC₅₀ values as obtained from DPPH and FRAP experiments were significantly (p≤0.05) lower in irradiated fruits compared to control.     

Fundamental studies on the feasibility of deep eutectic solvents for the selective partition of glaucarubinone present in the roots of Simarouba glauca

Several deep eutectic solvents prepared by the complexation of choline chloride as the hydrogen bond acceptor and hydrogen bond donors such as urea, thiourea, ethylene glycol, and glycerol were employed to partition glaucarubinone, an antimalarial compound present in roots of the plant, Simarouba glauca. Among all the solvents, the deep eutectic solvent consisting of the mixture of choline chloride and urea the most suitable to partition the antimalarial compound from the extract selectively. Analytical tools such as high‐performance liquid chromatography and electrospray ionization mass spectrometry were used for characterizations, and glaucarubinone extracted from the roots of the plant by conventional solvent extraction method was used as a reference for comparison. The hydrogen and noncovalent bonds formed between glaucarubinone and the deep eutectic solvents could be responsible for the selective partition of the drug molecule.     

Shoot organogenesis from root-derived callus of Rhinacanthus nasutus (L.) Kurz. and assessment of clonal fidelity of micropropagted plants using RAPD analysis

An efficient regeneration system was established for an ethnomedicinal shrub Rhinacanthus nasutus from root-derived callus organogenesis. The root segments were cultured on MS medium supplemented with various concentrations of Kn (1.0–4.0 μM) alone or in combination with IBA (0.2–0.6 μM) or 2, 4-D (0.5–1.5 μM). The optimum frequency (94 %) of callus induction was recorded on MS medium supplemented with 3.0 μM Kn and 0.4 μM IBA. For shoot regeneration from callus, MS medium supplemented with different concentrations (1.0–7.0 μM) of BA or TDZ alone or in combination with NAA (0.2–1.0 μm) was employed. The highest frequency of shoot regeneration (91 %) and mean number of shoots (28.3) were observed on MS medium supplemented with 5.0 μM BA and 0.7 μM NAA. The shoots were excised and cultured on MS medium with 4.0 μM IBA produced 3.4 roots per shoot in 88 % cultures. Of the 65 plants transferred to soil 54 survived (83 %). The plants were transferred to field after successful hardening. RAPD analysis of the regenerated plants showed high similarity with the mother plant.     

Facile synthesis of N‐α‐boc‐1,2‐dialkyl‐l‐histidines: Utility in the synthesis of thyrotropin‐releasing hormone (trh) analogs and evaluation of the cns activity

A facile synthesis of N‐α‐Boc‐1,2‐dialkyl‐L‐histidines starting from N‐α‐trifluoroacetyl‐L‐histidine methyl ester is reported. The key steps involve direct and regiospecific N‐1(τ) ring‐alkylation of the N‐α‐trifluoroacetyl‐L‐histidine‐methyl ester by suitable alkyl iodide in the presence of NaH in DMF at ?15 °C followed by homolytic free radical C‐2 alkylation via a silver catalyzed oxidative decarboxylation of alkylcarboxylic acid in the presence of ammonium persulfate under acidic conditions. The application of newly synthesized bioimidazoles was illustrated by their incorporation into thyrotropin‐releasing hormone (TRH). The synthesized TRH analogs were evaluated in vivo for analeptic activity. We report discovery of a TRH analog, which was found to potentiate the pentobarbital‐induced sleep in vivo.     

Compounds of imidazoles with ruthenium(III) chloride

Summary Reaction of ruthenium(III) chloride with imidazole(Im) and different substituted imidazoles,viz. N-methylimidazole (N-MeIm), 2-methylimidazole(2-MeIm), 4-methylimidazole (4-MeIm),N-vinylimidazole(N-VIm), 2-methyl- 1-vinyl-imidazole(2-Me-1-VIm), 1,2-dimethylimidazole(1,2-Me,Im), 2-ethylimidazole(2-EtIm) and 2-ethyl-4(5)-methylimidazole (2-Et-4(5)-MeIm] yield products of the types [Ru₂L₄Cl₆] · 2 H₂O (L = N-VIm or 4-MeIm), [Ru₂L₄Cl₆] · 4 H₂O (L = Im or 2-Et-4(5)-MeIm), [Ru₂L ³ (H₂O)Cl₆] (L =N-MeIm or 2-MeIm), [Ru₂L ² (H₂O)₂Cl₆] (L = 1,2-Me₂Im or 4-MeIm), [Ru(2-Me-1-VIm)₃Cl₃] · H₂O and [Ru(2-EtIm)₃(H₂O)Cl₂]. These compounds were characterised by elemental analyses, conductometric measurements, i.r. and electronic spectral analyses. Magnetic moments range from 1.01 to 1.9 B.M. The e.s.r. spectra and g values of some of the compounds are indicative of high distortion.     

Polymeric complexes of bivalent transition metal ions with 2-hydroxy-1-naphthaldehyde oxaldihydrazone and 2-hydroxy-1-naphthaldehyde malondihydrazone

Summary Polymeric complexes prepared by solid-solution reactions, from 2-hydroxy-1-naphthaldehyde oxaldihydrazone (HNODH) and 2-hydroxy-1-naphthaldehyde malondihydrazone (HNMDH), had the empirical composition M(L-2H)·nH₂O where M=Fe^II, Mn^II, Co^II, Ni^II, Cu^II, Zn^II, Cd^II and Hg^II; L=HNODH, HNMDH andn=0,1, 2. The complexes, which are intensely coloured and insoluble in common organic solvents, were characterized by elemental analysis, magnetic susceptibility, electronic and i.r. spectral data. The absence of anions indicates that the ligands which bind the metal ions from the hydroxyl and the imino groups have been deprotonated.     

Nano-TiO2-Induced Apoptosis by Oxidative Stress-Mediated DNA Damage and Activation of p53 in Human Embryonic Kidney Cells

The aim of the present study is to explore the mechanism of cytotoxic and genotoxic effects of TiO₂ nanoparticles on human embryonic kidney (HEK-293) cells. Toxicity was evaluated using changes in various cellular parameters of HEK-293 cells like morphology, viability, metabolic activity, oxidative stress and apoptosis. Oxidative stress was measured by the level of reactive oxygen species (ROS), lipid peroxidation, superoxide dismutase, catalase and glutathione peroxidase. Apoptosis induced by nano-TiO₂ was characterized by PI staining and DNA ladder assay. Furthermore, apoptotic proteins such as p53 and Bax were analysed by western blot. Our results indicate that nano-TiO₂ induces cytotoxicity in a time- and dose-dependent manner. Oxidative stress and apoptosis were induced by exposure to nano-TiO₂. Moreover, the expression of p53, Bax and caspase-3 were increased in a dose-dependent pattern. In conclusion, ROS-mediated oxidative stress, the activation of p53, Bax, caspase-3 and oxidative DNA damage are involved in the mechanistic pathways of nano-TiO₂-induced apoptosis in HEK-293 cells.