Synthesis, Characterization and Antibacterial Properties of Silver Nanoparticles in Clay and Organic Polymers as Nanocomposites

In this study, silver nanoparticles (Ag NPs) with the small size (2.12–30.63 nm) were successfully synthesized in the lamellar space of montmorillonite (MMT), montmorillonite/chitosan (MMT/Cts), porous zeolite framework and external surface layer of talc by chemical reducing agent in the absence of heat treatment. The most favourable experimental condition for the synthesis of Ag NPs in the MMT, talc, zeolite nanocomposites (NCs) and silver/montmorillonite/chitosan bionanocomposites (Ag/MMT/Cts BNCs) are described in terms of the initial concentrations of AgNO3. The mean diameters and standard deviation of Ag NPs in all of solid supports increased gradually with the increase of silver ions concentration. The external morphologies indicate that there are no noteworthy morphological distinctions between solid substrates and Ag NPs incorporated to them. The Ag NPs by the physical synthetic route were synthesized in the lamellar space of MMT/Cts utilising the UV-irradiation reduction method in the absence of reducing agent or heat treatment. The properties of Ag/MMT/Cts BNCs were studied as the function of UV-irradiation times. UV-irradiation disintegrated the Ag NPs into smaller size until a relatively stable size and size distribution were achieved. The silver nanocrystals were also synthesized by another physical method into the interlamellar space of MMT by using ƴ-irradiation in the absence of reducing agent or heat treatment. The properties of Ag/MMT NCs and the diameters of Ag NPs were studied as a function of ƴ-irradiation doses. The results from the UV-visible spectroscopy and TEM demonstrated that increasing the ƴ-irradiation doses enhanced the concentration of Ag NPs. In addition, the particle size of Ag NPs gradually increased from 1 until 20 kGy. When the ƴ-irradiation doses increased from 20 to 40 kGy, the particle diameters decreased suddenly as a result of the induced fragmentation for Ag NPs. Moreover silver/poly(lactic acid) nanocomposites (Ag/PLA NCs) films were investigated, while Ag NPs were synthesized into the biodegradable PLA as a polymeric matrix and stabilizer in the presence of sodium borohydride as a chemical reduction agent in diphase solvent. In all preparation, MMT, talc and zeolite were used as the inorganic solid supports and poly(lactic acid) was used as organic polymeric matrix. The silver nitrate, chitosan, and sodium borohydride were used as the silver precursor, natural and biodegradable polymeric stabilizer, and the reduction agent respectively. The crystalline structure of Ag NPs for all of samples, average size and size distributions, surface plasmon resonance, surface morphology, and functional groups were studied using X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-visible spectroscopy (UVvis), scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) respectively. The XRD analysis confirmed that the crystallographic planes of the silver crystals were the face-centred cubic (fcc) types. The UV-visible absorption spectra showed the peaks characteristic of the surface plasmon resonance (SPR) bonds of Ag NPs. The antibacterial activities of Ag NPs were investigated against Gram-negative and Gram-positive bacteria by the disk diffusion method using Mueller-Hinton Agar (MHA) at different sizes and amounts of Ag NPs. Results show that the antibacterial activity of Ag NPs can be modified with the particle size of Ag NPs

Effect of heat treatment on thermal diffusivity of Zn/Al layered double hydroxide synthesized using photoflash technique

Thermal diffusivity of zinc-aluminum layered double hydroxides was synthesized at different molar ratio of zinc and aluminum salts in the pH=7 and measured by using polyvinlidene diflouride (PVDF) by photoflash technique. The samples were prepared using Zn(NO3)2 and Al(NO3)3 solutions by drop wise addition of NaOH solution with vigorous stirring under nitrogen atmosphere. The samples then heat treated by control an electrical furnace from 200 to 600 °C for 5 hours. Thermal diffusivity was increased for all samples after sintering. The samples were studied by powder x-ray diffraction method, Fourier transform infrared (FTIR), scanning electron microscope (SEM) and thermal diffusivity. Our results indicate the very different role of sintering in the structure and thermal diffusivity of samples

Synthesis and characterization of rice straw/Fe3O4 nanocomposites by a quick precipitation method

Small sized magnetite iron oxide nanoparticles (Fe3O4-NPs) with were successfully synthesized on the surface of rice straw using the quick precipitation method in the absence of any heat treatment. Ferric chloride (FeCl3·6H2O), ferrous chloride (FeCl2·4H2O), sodium hydroxide (NaOH) and urea (CH4N2O) were used as Fe3O4-NPs precursors, reducing agent and stabilizer, respectively. The rice straw fibers were dispersed in deionized water, and then urea was added to the suspension, after that ferric and ferrous chloride were added to this mixture and stirred. After the absorption of iron ions on the surface layer of the fibers, the ions were reduced with NaOH by a quick precipitation method. The reaction was carried out under N2 gas. The mean diameter and standard deviation of metal oxide NPs synthesized in rice straw/Fe3O4 nanocomposites (NCs) were 9.93 ± 2.42 nm. The prepared rice straw/Fe3O4-NCS were characterized using powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray fluorescence (EDXF) and Fourier transforms infrared spectroscopy (FT‒IR). The rice straw/Fe3O4-NCs prepared by this method have magnetic properties

THE SURVEY OF THE BARRIERS TO NOT REPORTING MEDICATION ERRORS FROM THE PERSPECTIVE OF NURSING STUDENTS

ABSTRACTObjective: Reporting the medication errors, on the one hand, causes the preservation and observation of the patient security, and on the other hand,it is regarded as a valuable information treasure in line with the prevention of the medication errors expression in the future. Therefore, the presentstudy has been conducted with the objective of the survey of barriers to medication errors reporting from the perspective of the nursing students.Methods: This study is a descriptive research which has been conducted on 87 nursing students who have been selected based on a random method. Togather the required information, there has been made use of a two-part questionnaire, the first part of which deals with the study of the demographiccharacteristics and the second part pertains to the factors influencing not reporting the medication errors. In the end, after the necessary informationcollected the data were analyzed by taking advantage of SPSS 19 and descriptive statistics.Results: The individuals average age in the present study was 21.09±2.48, 51 individuals were female. 24 individuals were studied in semester4, 31 people were passing term 6, and 32 individuals were in term 8. The highest mean score as obtained in managerial aspect. In addition, the highestmean score was related to the items concentration of the managers solely on the person who has made the mistake and disregarding of the otherfactors involved in mediation error†and lack of receiving a positive feedback from the nursing supervisors following reporting the medication errorâ€and the lowest mean score was related to the item not being considerate to some of the medication errors reporting.â€Conclusion: The results of this study indicated that the highest mean score for not reporting the medication errors went to the managerial dimensions.Therefore, the supervisors and the nursing staff should be cautioned regarding their behavior, regarding the medication errors reporting, and considerthe problems and issues systematically.Keywords: Medication error, University students, Zahedan, Nursing

Dielectric and electrical characteristics of mechanically synthesized Ni-Zn ferrite nanoparticles

Ni-Zn ferrite nanoparticles were synthesized via mechanical activation of Zn, NiO and Fe2O3 powders in a high energy planetary ball mill. The 30 h-milled samples in argon, oxygen and air atmospheres were pressed in pellet and toroid shape form and were sintered from 500 °C to 900 °C with 100 °C increments. The X-ray diffraction patterns results indicated a single phase Ni-Zn ferrite formation with a cubic-spinel structure in all the samples sintered at 500 °C. The milling atmosphere had a key role in the synthesis, microstructure and properties of the samples in such a way that this effect sustained even after the completion of sintering process. Thus, the main goal of this study is to scrutinize the effect of sintering temperature in the 30-h-milled samples in different atmospheres on DC electrical resistivity and dielectric behavior of Ni-Zn ferrite samples. The results indicated that although electrical resistivity decreased, dielectric behaviors, i.e. constant, loss and tan increased with increase in sintering temperature. The milled samples in argon had the highest resistivity of 1.2 106 Ωcm at 500 °C, and lowest dielectric constant and loss (4.67 102 and 1.7 at 300 K and frequency 106 MHz, respectively) compared to other samples owing to more homogeneity and smaller average crystallite size, making them a good candidate for high frequency applications. X-ray photoelectron spectroscopy (XPS) revealed the presence of metal ions in their proper valence in the Ni-Zn ferrite crystal structure. Noticeably, a variation in the binding energy for the milled samples in different atmospheres is attributed to the changes in surroundings of Fe3+ and Zn2+/or Ni2+, due to non-equilibrium distribution of cations in tetrahedral and octahedral sites, which is further confirmed by the XRD patterns