Fluorine doped CNTs for efficient OER activity outperforming iridium supported carbon electrocatalyst

Journal of Applied Electrochemistry - Herein, we report the low-temperature fluorine doping into carbon nanotubes (CNTs) by solid-state fusion method using xenon fluoride (XeF2) as a precursor of...     

Smart hybrid SDN approach for MPLS VPN management on digital environment

Telecommunication Systems - MPLS VPN is growing in front of the other network layer tunneling technologies of the OSI model. The trend related to this technology is justified mainly by the...     

Synthesis of Modified RGD-Based Peptides and Their in vitro Activity

Arg-Gly-Asp (RGD) peptides represent the most outstanding recognition motif involved in cell adhesion that binds to the α_vβ₃ integrin, which has been targeted for cancer therapy. Various RGD-containing peptides and peptidomimetics have been designed and synthesized to selectively inhibit this integrin. In this study, the synthesis of RGD-based peptides through the incorporation of the short bioactive peptide Phe-Ala-Lys-Leu-Phe (FAKLF) at the C and N termini of RGD has been achieved by using a solid-phase peptide synthesis approach. The peptides were purified by means of preparative RP-HPLC and their structures were confirmed through HRMS (ESI). The MTT assay revealed that the RGD and FAKLF peptides inhibited the proliferation of human umbilical vein endothelial cells (HUVECs) in a dose-dependent manner, with IC₅₀ values of 3000 and 500 ng mL⁻¹, respectively. Interestingly, a drastic improvement was observed in the antiproliferative activity of the combined structures of the FAKLFRGD and RGDFAKLF peptides, leading to IC₅₀ values of 200 and 136.7 ng mL⁻¹, respectively. Meanwhile, based on apoptosis results, the potential of peptides to induce apoptosis, in accordance with their antiproliferative activity, indicated that the RGD and FAKLF peptides, and the peptides synthesized based on their combinations induced cell apoptosis in a dose-dependent manner followed by inhibition of the proliferation of endothelial cells. Moreover, the incorporation of d -leucine increased the induction of apoptosis by these peptides.     

Biodiesel production from green seaweed Ulva fasciata catalyzed by novel waste catalysts from Pakistan Steel Industry

This research article is based on the biodiesel synthesis from the marine green macroalga Ulva fasciata, collected from the coast of Karachi, Pakistan using new and the most potential waste catalysts from Pakistan Steel Industry.The oil was extracted with n-hexane then it was analyzed by GC, TLC and by the examination of fuel properties.The metal analysis of catalysts was carried out by chemical tests and flame atomic absorption spectroscopy(FAAS). The thermal treatment of catalysts at 1500–1700 °C during various processes in steel manufacturing industry converted the metals to metal oxides. The presence of CaO, MgO and ZnO in these catalysts made them highly reactive for biodiesel synthesis. The basicity of waste industrial catalysts was calculated to know their basic strength. The transesterification of U. fasciata oil was performed by fast stirring using 9:1 molar ratio of methanol/oil in the presence of seven different waste industrial catalysts for 6 h at 80–100 °C. The solid catalysts were easily separated from product for re-use. In addition, the rate of reaction in the presence of these catalysts was found to be quite feasible. The waste brown dust from the steel converter gave the highest yield(88%) of biodiesel. The production of biodiesel was confirmed by TLC examination and fuel properties in comparison with the ASTM standards.     

Structural and magnetic studies of Ce-Zn doped M-type SrFe12O19 hexagonal ferrite synthesized by sol-gel auto-combustion method

In the present work, the M-type Sr-hexagonal ferrites having chemical composition Sr_1-xCe_xFe_12-yZn_yO₁₉ (x?=?0.000, 0.025, 0.050, 0.075, 0.10, y?=?0.00, 0.25, 0.50, 0.75, 1.0) are prepared via sol-gel autocombustion technique. The Structural and magnetic properties of M-type Sr-hexagonal ferrites are studied and discussed thoroughly. The structural, micro graphical and magnetic particularities of the samples are calculated through X-Ray diffraction (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometer (VSM) respectively. X-ray diffraction assured that all the synthesized composites possess a pure M-type hexaferrite structure and basic crystalline configuration of Sr-hexaferrite which does not alter by Ce-Zn substitution. It is observed that the Ce-Zn substitution has significant effect on its magnetic properties. VSM results reveal that pure sample has coercivity of 4.49?kOe, which shows the hard nature of the samples. It is perceived that values of remanence (M_r) and saturation magnetization (M_s) decline with increasing the Ce-Zn ions substitution. The reason behind the reduction in magnetic saturation (M_s) and remanence (M_r) might be spin canting and dilution phenomena with increasing the rare earth substituted ions. The large coercivity magnets may be valuable for permanent (stable) magnet applications. The prepared composites could be useful for applications in microwave absorbing materials.     

Synthesis,Characterization, and Computational Study of New Ferrocene-Based Schiff Bases as Potential Nonionic Surfactants

Ferrocene-based nonionic surfactants were synthesized by reacting ferrocenylcarboxyaldehyde with different long-chain amines. Nonionic surfactants were characterized using Fourier transform infrared spectra (FT-IR), ¹HNMR, and ¹³CNMR spectroscopy. The ferrocene-based surfactants were characterized using ultraviolet (UV)–visible spectroscopy and surface tension measurements to determine the critical micelle concentration (CMC). The CMC values indicate high aggregation ability of the synthesized surfactants in ethanol. Dominance of their hydrophilic character was ensured from hydrophilic–lipophilic balance in the 10–15 range. Voltammetric response of all surfactants showed well-defined and stable redox signals. Computational studies further revealed their physicochemical characteristics. Results of the study confirm the multifunctionality of the surfactants and suggest utilization in various fields.     

An investigation of the bacteriocinogenic potential of lactic acid bacteria associated with wheat (Triticum durum) kernels and non-conventional flours

One hundred and thirty-seven lactic acid bacteria (LAB), previously isolated from wheat (Triticum durum) grains and non-conventional flour samples, were tested for the production of antibacterial substances. A total of 16 strains (5 Enterococcus faecium, 5 Enterococcus mundtii, 4 Pediococcus pentosaceus, 1 Lactobacillus coryniformis and 1 Lactococcus garvieae) were found to inhibit the growth of Listeria innocua. The antibacterial activities were preliminarily investigated for their general behaviour with proteolytic (proteinase K, protease B and trypsin), amylolytic (α-amylase) and lipolytic (lipase) enzymes, after heat treatment, and exposure to different pHs and ethanol concentrations. Bacteriocin-like inhibitory substances (BLIS) were also characterized for their inhibition spectra against non-pathogenic and pathogenic food-associated and human pathogenic bacteria. LAB showing the best characteristics in terms of inhibition spectrum, inhibition activity and mode of action (bactericidal) belonged to the species Ent. mundtii. The high percentage (11.68%) of BLIS-producing strains detected confirmed previous observations that raw materials may harbour higher numbers of bacteriocinogenic LAB than fermented foods.     

Effect of gamma irradiation on the extraction yield, total phenolic content and free radical-scavenging activity of Nigella staiva seed

In the present study, the radiation processing of Nigella sativa seed samples was carried out at dose levels of 2, 4, 8, 10, 12 and 16 kGy. The extraction yield, total phenolic content and 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical-scavenging activity of both control and irradiated samples extracted in acetone, methanol and water were assessed. The results showed that the extraction yields increased with an increase in radiation dose for all the test solvents. At 16 kGy the increases were 3.7%, 4.2%, 5.6% and 9.0% for hexane, acetone, water and methanol extracts, respectively. The phenolic content in the acetone extract was found to be increased from 3.7 for the control sample to 3.8 mg/g for the 16 kGy radiation-processed sample. No significant change was observed for the phenolic content of the methanolic extract, while the aqueous extract showed a decrease at dose levels of 12 and 16 kGy. In the control samples, the DPPH radical-scavenging activity was 79.4%, 79.1% and 92.0% for water, acetone and methanol extracts, respectively, at 5 mg/ml concentration. Gamma irradiation enhanced the scavenging activity in acetone and methanol extracts by 10.6% and 5.4%, respectively, at 16 kGy. In summary, gamma irradiation increased the extraction yield and total phenolic content, as well as enhancing the free radical-scavenging activity. In addition, the type of solvent used for extraction also affected the impact of irradiation on antioxidant activity and total phenolic content of N. sativa seed.     

Phosphonium iodine as nickel corrosion inhibitor in 1 M sulfuric acid medium

The inhibiting action of alkyltriphenylphosphonium iodine salt ((C₈H₁₇)Ph₃P⁺,I⁻) towards the corrosion behaviour of nickel in 1 M H₂SO₄ solution has been studied. This compound was found to retard both anodic and cathodic reactions of nickel corrosion. At constant temperature, the corrosion rate decreases with increasing inhibitor concentration. On the other hand, the increase in temperature leads to an increase in the corrosion rate. The activation energy, ΔE _a, were calculated. They were found 19.3 kJ mol⁻¹ and 71.1 kJ mol⁻¹, respectively for the uninhibited solution and in the presence of 10⁻³ M of phosphonium salt. The inhibitor adsorption was identified to occur according to Langmuir isotherm. The equilibrium constant, k, as well as the free energy of adsorption, Δ_ads G°, for inhibitor process were then calculated. Phosphonium iodine exhibited a singular behaviour for T ≥ 318 K where inhibitor desorption increases.