Green synthesis of silver nanoparticles using aqueous extract of Stachys lavandulifolia flower,and their cytotoxicity,antioxidant, antibacterial and cutaneous wound‐healing properties

In a biological process where the herbal tea (Stachys lavandulifolia) aqueous extract was applied as a capping and reducing agent, nanoparticles (NPs) of silver (Ag) were synthesized. These AgNPs were characterized using Fourier transform‐infrared spectroscopy, field emission‐scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, transmission electron microscopy and ultraviolet–visible spectroscopy. The synthesized AgNPs had great cell viability dose‐dependently [investigating the effect of the plant on human umbilical vein endothelial cell line] and indicated this method was non‐toxic. In this study, the 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) free radical scavenging test was carried out to examine antioxidant properties, which revealed similar antioxidant properties for AgNPs and butylated hydroxytoluene. Agar diffusion tests were applied to determine the antibacterial characteristics. The macro‐broth tube test was run to determine minimum inhibitory concentration. All data of antibacterial and cutaneous wound‐healing examinations were analyzed by SPSS 21 software (Duncan post hoc test). AgNPs showed higher antibacterial property than all standard antibiotics (p ≤ 0.01). Also, AgNPs prevented the growth of all bacteria at 2–8 mg/ml concentrations and destroyed them at 2–16 mg/ml concentrations (p ≤ 0.01). For the in vivo experiment, after creating the cutaneous wound, the rats were randomly divided into six groups: untreated control; treatment with Eucerin basal ointment; treatment with 3% tetracycline ointment; treatment with 0.2% AgNO₃ ointment; treatment with 0.2% S. lavandulifolia ointment; and treatment with 0.2% AgNPs ointment. These groups were treated for 10 days. For histopathological and biochemical analysis of the healing trend, a 3 × 3‐cm section was prepared from all dermal thicknesses at day 10. Use of AgNPs ointment in the treatment groups substantially reduced (p ≤ 0.01) the wound area, total cells, neutrophil, macrophage and lymphocyte, and remarkably raised (p ≤ 0.01) the wound contracture, hydroxyl proline, hexosamine, hexuronic acid, fibrocyte and fibrocytes/fibroblast rate compared with other groups. Seemingly, AgNPs can be used as a medical supplement owing to their non‐cytotoxic, antioxidant, antibacterial and cutaneous wound‐healing properties.     

Efficient aerobic photooxygenation of aldehydes to carboxylic acids using cobalt(II) phthalocyanine sulfonate as a photosensitizer in organic-water biphasic media

Transition Metal Chemistry - The aerobic oxidation of a variety of aromatic aldehydes to the corresponding carboxylic acids by molecular oxygen in the presence of 4-carboxyl tetraphenylporphyrin...     

A mechanistic study on the synthesis of branched functional polyethylene through reactive co-polymer approach

The reactive co-polymer approach is one of the most promising techniques for the synthesis of functional polyolefins. Following this concept, 1-hexene and p-methylstyrene are co-polymerized in the presence of a generic Brookhart-type catalyst. The microstructures of the co-polymers imply the tendency of p-methylstyrene co-monomers to place at the end of the structural branches formed by the chain walking reaction. The molar masses of the co-polymers decrease, not only at higher levels of co-monomer but surprisingly by decreasing reaction temperature. A mechanism consisting of a highly stable η³ metal–benzyl intermediate, which is quantitatively approved by density functional theory calculations, can delicately justify all the aforementioned observations. A series of the produced co-polymers is selectively functionalized by maleic anhydride at the benzylic position of p-methylstyrene, under very mild reaction conditions. Such a reactive intermediate opens the path for the introduction of different types of functionalities in polyolefins. Namely, the grafted co-polymers were further functionalized by a triazole ring, which provides a transient supramolecular network through intermolecular hydrogen bonding.     

Suppressor capacity of iron nanoparticles biosynthesized using Salvia chloroleuca leaf aqueous extract on methadone-induced cell death in PC12: Formulation a new drug from relationship between the nanobiotechnology and neurology sciences

Metallic nanoparticles have gained significant attention in the area of biomedical technology. Because of its high surface area, metallic nanoparticles are being widely used in various fields including the medical and engineering sciences. One of the valuable applications of metallic nanoparticles especially copper, zinc, and iron nanoparticles is increasing the physiological function of central nervous system. Besides, Iranian people are using the Salvia chloroleuca for neuroprotective properties. In the present research, iron nanoparticles were biosynthesized by S. chloroleuca leaf aqueous extract as reducing and stabilizing agents. Also, we revealed the protective effect of FeNPs in methadone-treated PC12 cells. FeNPs were characterized and analyzed using common nanotechnology techniques including FT-IR, UV–Vis. spectroscopy; EDS, TEM, and FE-SEM. TEM and FE-SEM images revealed a uniform spherical morphology for FeNPs. In the biological part of the current study, the both treatments of FeNPs significantly (p ≤ 0.01) reduced the cell cytotoxicity and cell death index as well as increased the cell viability and cell proliferation in methadone-treated PC12 cells. In these treatments, mitochondrial membrane potential significantly (p ≤ 0.01) increased compared to methadone-induced PC12 cells. DPPH free radical scavenging test was did to evaluate the antioxidant potentials of FeCl₃, S. chloroleuca, and FeNPs. DPPH test indicated similar antioxidant activities for S. chloroleuca, FeNPs, and butylated hydroxytoluene. In current experiment, we concluded that iron nanoparticles biosynthesized by S. chloroleuca leaf aqueous extract suppressed methadone-induced cell death in a dose-dependent manner in PC12 cells.     

Energetic,exergetic, environmental and economic assessment of a novel control system for indirect heaters in natural gas city gate stations

Journal of Thermal Analysis and Calorimetry - The energy consumption and greenhouse gases emissions in natural gas city gate stations are important issues in the natural gas industry. In order to...     

Effect of gold nanoparticles synthesized using the aqueous extract of Satureja hortensis leaf on enhancing the shelf life and removing Escherichia coli O157:H7 and Listeria monocytogenes in minced camel's meat: The role of nanotechnology in the food industry

Because herbal nanoparticles have antimicrobial properties, researchers have tried to synthesize them to aid in increasing the shelf time of food and food products. In this regard, gold nanoparticles (AuNPs) synthesized by plants are particularly important. In this study, fresh and clean leaves of Satureja hortensis were selected for the synthesis of AuNPs. We also evaluated the efficacy of these nanoparticles to increase the shelf life of and remove Escherichia coli O157:H7 and Listeria monocytogenes from minced camel's meat. The nanoparticles were analyzed by UV–visible spectroscopy, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier-transform infrared (FT-IR) spectroscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction tests. The FT-IR spectroscopy results demonstrated that the antioxidant compounds in the plant were the sources of reducing power, reducing gold ions to AuNPs. FE-SEM and TEM images revealed the size of the nanoparticles to be 22.26 nm. The 2,2-diphenyl-1-picrylhydrazyl test revealed similar antioxidant potentials for S. hortensis, AuNPs, and butylated hydroxytoluene. S. hortensis and AuNPs had high cell viability dose-dependently against the human umbilical vein endothelial cell line. At the beginning of the food industry part of this experiment, all samples of control, S. hortensis, and AuNPs were preserved at 4°C for 20 days. During these 20 days, the sensory, chemical, and microbiological parameters were assessed for all samples. AuNPs significantly inhibited the growth of E. coli and L. monocytogenes. In addition, AuNPs significantly increased the protein carbonyl content, thiobarbituric acid reactive substances, pH, peroxide value, total volatile base nitrogen, and sensory attributes (color, odor, and overall acceptability). The best results were seen in AuNPs (1%). These findings reveal that the inclusion of S. hortensis extract improves the solubility of AuNPs, which led to a notable enhancement in their preservative and antibacterial effects.     

Finite element modeling of a generic stemless hip implant design in comparison with conventional hip implants

In this study, the finite element modeling and comparison of the stress and strain analyses were carried out for three different structures that are intact bone, stemless implant and stemmed one. Currently proposed stemless design studied here is the generic concept of stemless implant. This generic stemless implant reconstruction was numerically compared to the conventional stemmed implant and also to the intact bone as control solution. Two loading conditions were applied to the most proximal part of the models, while the most distal part was fixed for all degrees of freedom. The models were divided into two regions and studied along two paths of medial and lateral aspect. The results of this study showed that the stemless implant had less deviation from the control solution of the bone in all regions and in both loading conditions, comparing to the large deviation of the stemmed implant from the intact bone. However, it was shown that the fixation of this type of implant and its effect on sub-trochanter region must be carefully considered for designing the final product of any specific design of stemless implant.     

Characterization of a dual wavelength fibre laser based-on dumbbell configuration

This paper reports the design of a dual wavelength fibre laser system using a dumbbell shaped configuration. The oscillation of the lasing wavelength is completed via fibre loop mirrors with a tuneable bandpass filter. The output power, side mode suppression ratio and wavelength spacing of the lasers were investigated against the pump power for forward and backward pumping schemes. The output powers of 4.99 and 3.69 dBm at 1545.08 and 1547.28 nm, respectively, for forward pumping scheme. On contrary, the output powers of 1.93 and 2.14 dBm at 1546.12 and 1551.48 nm, respectively, for backward pumping scheme. The peak output powers of less than 1 dB difference are obtained without any adjustment of the intra-cavity loss over a wider spectral range.     

Enhanced nonlinear 3D Euler–Bernoulli beam with flying support

Using Hamilton’s principle the coupled nonlinear partial differential motion equations of a flying 3D Euler–Bernoulli beam are derived. Stress is treated three dimensionally regardless of in-plane and out-of-plane warpings of cross-section. Tension, compression, twisting, and spatial deflections are nonlinearly coupled to each other. The flying support of the beam has three translational and three rotational degrees of freedom. The beam is made of a linearly elastic isotropic material and is dynamically modeled much more accurately than a nonlinear 3D Euler–Bernoulli beam. The accuracy is caused by two new elastic terms that are lost in the conventional nonlinear 3D Euler–Bernoulli beam theory by differentiation from the approximated strain field regarding negligible elastic orientation of cross-sectional frame. In this paper, the exact strain field concerning considerable elastic orientation of cross-sectional frame is used as a source in differentiations although the orientation of cross-section is negligible.