AFM Investigation of Epoxy Fracture Surfaces Indicating Nanoplasticity

Noble metal nanoparticles have a great potential for biological study, especially the use of gold nanoparticles is very popular. In this work gold nanoparticles (GNPs), silver nanoparticles (SNPs) and goldsilver hybrid nanoparticles (HNPs) synthesized and used as a carrier for electrochemical investigation of redox protein. Optical characterization of these nanoparticles was performed by UV-Vis spectroscopy. The maximum of the plasmon band for GNPs, SNPs and HNPs (ratio of 1:1) are 524, 392 and 455 nm respectively. The optical absorption spectra of HNPs solution shows only one plasmon absorption, it is concluded that mixing of gold and silver leads to a homogeneous formation of alloy nanoparticles. LCR meter study shows the HNPs is best conductance in compare of GNPs and SNPs. Therefore, the electron transfer of the homogenous GOx, HRP and Hb was investigates by electrochemical method in presence of HNPs. They demonstrated quasi-reversible cyclic voltammograms with a formal potential of -479, -178 and -168 mV in 50 mM phosphate buffer solution at pH 7.4 respectively

AFM Investigation of Epoxy Fracture Surfaces Indicating Nanoplasticity

Noble metal nanoparticles have a great potential for biological study, especially the use of gold nanoparticles is very popular. In this work gold nanoparticles (GNPs), silver nanoparticles (SNPs) and goldsilver hybrid nanoparticles (HNPs) synthesized and used as a carrier for electrochemical investigation of redox protein. Optical characterization of these nanoparticles was performed by UV-Vis spectroscopy. The maximum of the plasmon band for GNPs, SNPs and HNPs (ratio of 1:1) are 524, 392 and 455 nm respectively. The optical absorption spectra of HNPs solution shows only one plasmon absorption, it is concluded that mixing of gold and silver leads to a homogeneous formation of alloy nanoparticles. LCR meter study shows the HNPs is best conductance in compare of GNPs and SNPs. Therefore, the electron transfer of the homogenous GOx, HRP and Hb was investigates by electrochemical method in presence of HNPs. They demonstrated quasi-reversible cyclic voltammograms with a formal potential of -479, -178 and -168 mV in 50 mM phosphate buffer solution at pH 7.4 respectively

Carbapenem-resistant Acinetobacter baumannii recovered from burn patients

Purpose. Emergence of carbapenem-resistant Acinetobacter baumannii (CRAB) and their prolonged presence in burn units increases the risk of acquisition of CRAB. Methods. From November 2012 to September 2013, 1474 burn patients were screened for CRAB isolates through testing susceptibility to imipenem and its comparators meropenem, and doripenem. Furthermore, the in vitro activity of other antibiotics against CRAB was investigated. Results. Three patients were infected with carbapenem-susceptible A. baumannii (CSAB) and 168 were infected with CRAB. Approximately one-fifth (n=32) of CRAB isolates were obtained from patients hospitalized in Burn Intensive Care Unit (BICU). Most of CRABs were isolated from wound. The mean length of stay (LOS) in hospital prior to A. baumannii isolation was significantly higher for CRAB compared to CSAB cases (P=0.04). Amongst the independent variables, percentage of total burn surface area (TBSA) significantly increased the mortality rate using multivariate logistic regression (P=0.001, OR= 16.5; 95 CI: 4.72-57.7). The majority of tested isolates were resistant to imipenem (94.8), and to its comparators, doripenem (97.7), and meropenem (97.7). The susceptibility of CRAB isolates was less than 10 to all tested antibiotics except for colistin (100), doxycycline (61.9), gentamicin (18.5), and tigecycline (11.9). Conclusion. Resistance to carbapenem reduces the number of effective antibiotics. The coordinated and intensive efforts of healthcare personnel are required to meet the challenge of dissemination of CRA

An investigation on the interaction modes of a single-strand DNA aptamer and RBP4 protein: A molecular dynamic simulations approach

Type two diabetes is one of the primary health issues threatening public well-being worldwide. One of the pre-diagnosis biomarkers of this disease, retinol binding protein 4 (RBP4), has been demonstrated to be detected with a 76-mer ssDNA aptamer instead of conventional antibodies. However, there is no structural information on the RBP4 binding aptamer (RBA) and the mechanism of its binding to RBP4 still remains unexplored. The objective of the present study is to achieve a better understanding of specific binding interactions of the target protein (RBP4) and RBA, employing Molecular Dynamics simulations (MDs) to provide detailed information on fluctuations, conformational changes, critical bases and effective forces to develop regulated aptamers to be employed in designing new aptamers for many useful recognition applications. RBA was designed according to its reported base pair sequence and secondary structure. The HADDOCK on line docking program was used to predict a suitable RBP4-RBA mode of interaction to start MDs with. MDs methodology was used to analyze the final complex stability and detect interacting residues. Eventually, we conclude that single strand located bases are the key components that conduct the intercalation phenomenon with big targets rather than those involving loops and folded motifs, to encompass targets and probably inhibit their activity. Also, UV-visible, circular dichroism and fluorescence spectroscopy measurements confirmed the interactions between RBA and RBP4 and RBP4-RBA complex formation. © 2016 The Royal Society of Chemistry

A silver(I) doped bud-like DNA nanostructure as a dual-functional nanolabel for voltammetric discrimination of methylated from unmethylated genes

A small DNA structure, referred to as DNA nanobud (NB), was used for the first time to design a dual-functional nanolabel in order to recognize a particular oligonucleotide sequence, generate and amplify the electrochemical analytical signal. NBs containing numerous repetitive desired sequences were prepared through self-assembly of 8-h rolling circle amplification. Then, redox-active silver ions were loaded onto the NBs by over-night incubation with a solution of AgNO3. The incorporation of Ag+ into NBs was confirmed by field emission scanning electron microscopy, dynamic light scattering, UV-Vis spectroscopy, zeta potential measurements, and energy-dispersive X-ray spectroscopy. A DNA sandwich complex was created after hybridization of Ag+-NB with target sequence, which was captured by immobilized probe on a gold electrode. Cyclic voltammetry was applied to measure the redox signal of silver ions produced typically at a potential around 0.02 V vs. Ag/AgCl. The label can specifically discriminate fully methylated BMP3 gene from fully unmethylated bisulfate-converted part of the gene. The electrochemical signal produced by DNA sandwich complex of gold/probe/BMP3/Ag+-NB was linear toward BMP3 concentration from 100 pM to 100 nM. The method has a 100 pM BMP3 detection limit. Conceivably, this nanolabel can be designed and modified such that it may also be used to detect other sequences with lower detection limits. Figure not available: see fulltext.. © 2018, Springer-Verlag GmbH Austria, part of Springer Nature

The Objectives of Engineering Education

In developing the models and approaches for engineering education, in addition to having technical knowledge (engineering science) there is a specific focus on skills and attitudes (engineering practice). Hence, the determination of engineering education objectives with regard to the required knowledge, skills, and attitudes for engineers is the basis of many studies in the present century. The aim of this paper is to determine the objectives of engineering education based on content analysis of present documents. The society in this research includes present documents in the context of engineering education objectives in which seven documents as purposeful samples and desirable cases were selected for analysis. The instruments for data collection were a checklist and researcher-made forms. The data was analyzed and interpreted by open coding and axial coding. Based on the performed content analysis, 24 objectives were determined for engineering education, which were classified into five categories. Then it was determined how the established objectives were supported by present documents. At last, based on the performed research in the field, the relation between assumed objectives with present documents was determined