Escherichia coli and Staphylococcus aureus are pathogens that have the ability to form biofilms and cause disease in food products. Due to the fact that the enterotoxins produced by these two pathogens remain in a wide range of temperature, pH and saline conditions, they cause severe infections in humans. Melittin is a natural peptide derived from bee venom that can show its antimicrobial and anti-biofilm potential through disrupting the membrane of bacterial cells. For this purpose, in this study, the antimicrobial effect of this peptide on Gram positive and negative bacteria was investigated and its minimum inhibitory concentration (MIC) was determined as 100 µg/mL and 300 µg/mL, respectively. Also, the scanning electron microscope images confirmed the antimicrobial effect of the peptide on these two bacteria. Peptide melittin caused wrinkling, deformation and creation of holes in the cell membrane of treated bacteria, compared to the control sample. On the other hand, the results of the biofilm inhibition test showed that the addition of the peptide at a concentration of 2MIC completely prevented the biofilm formation of S. aureus prevented, while this value was equal to 91.00 ± 2.82 in E. coli bacteria. Also, the increase in peptide concentration caused an increase in the destruction of adult biofilms of both bacteria. On the other hand, this peptide decreased the invasion and adhesion of these two bacteria to HT-29 and Caco-2 cells by reducing the mobility of pathogens. Therefore, according to the obtained results, melittin peptide can be a suitable alternative to chemical disinfectants that are harmful to the environment.

Background: Due to repeated cholera outbreaks in Iran and neighboring countries, the present study was performed to determine the prevalence of phenotypes of Ogawa and Inaba serotypes of Vibrio cholera 01 and classic Vibrio cholera 01 biotypes.Materials and methods: scanning and transmission electron microscopy (SEM and TEM) were applied on 4 species, of Ogawa and Inaba serotypes and two classic serotypes of Vibrio cholera 01. Results: Membrane diameter of Eltor was wider as compared to classic biotype. Number of ribosomes, protein synthesis, length and number of flagella were quite more in comparison with classic biotype. Conclusion: According to our findings, genome of classic biotype is more compact.

The properties of steels are intrinsically dependent on their microstructural components, known as phases, which form during the manufacturing process. Different steel phases can be observed in microscopic images of steel surfaces. Automatic detection and classification of these phases from images can significantly enhance the understanding of steel properties with improved speed and accuracy. This paper introduces, for the first time, an intelligent and automated method for classifying steel phases from microscopic images. This process requires defining and extracting suitable texture features unique to these images and segmenting the images into highly irregular regions based on the extracted features. To achieve this, the input image is initially divided into blocks, and texture features are extracted independently for each block. The dimensionality of these features is then reduced using Principal Component Analysis, and the refined features are subsequently fed into a Softmax neural network for classification. The implementation results indicate that the proposed method achieves an accuracy of over 99% in distinguishing between two phases: acicular ferrite and granular ferrite. Furthermore, it attains an accuracy exceeding 86% when classifying three phases: granular ferrite, acicular ferrite, and Widmanstätten ferrite. This suggests that the widely used and conventional k-means clustering method, as a traditional machine learning approach, is incapable of effectively distinguishing microscopic steel phase blocks using extracted texture features. Notably, as of the writing of this paper, no prior research has been conducted on the automatic classification of different ferrite phases, making this study a novel contribution to the field. In this research, an automated classification algorithm for ferrite phase structures in SEM images of steel is proposed using texture feature extraction methods and machine learning models. The dataset comprises images of 1024×768 resolution, which were divided into 128×128 blocks, with classification performed independently for each block. Due to the limited number of blocks available for training machine learning models, data augmentation techniques such as rotation and scaling were applied to increase the dataset size. Various image processing methods were used to extract 128 texture features. These extracted features were then used to classify different ferrite phases using two machine learning models: k-means clustering and the Softmax neural network. Additionally, PCA was employed to reduce feature dimensionality, which positively impacted the classification of granular and acicular ferrite. While k-means clustering, as a conventional and widely used machine learning method, failed to achieve satisfactory classification accuracy, the proposed approach using a smooth maximum neural network demonstrated exceptional performance. Despite the complex and irregular nature of ferrite shapes, the selected features and the proposed algorithm successfully achieved over 99% accuracy for two-phase classification and over 86% accuracy for three-phase classification.

Introduction. The lumen of the vascular system is covered by a continuous layer of endothelial cells, and any changes or damages to them is due to cardiovascular diseases especially atherosclerosis. Lead is one of the elements which may cause endothelial dysfunction. The purpose of this study was to determine the effect of lead on morphologic features of endothelium which may induce the endothelial dysfunction.Methods. Twenty white male rabbits divided randomly into two groups. Group A (n=11) were given regular diet with leaded water (547 ppm) and group B (n=9) were fed with regular diet and unlead water for 40 days. The animals were sacrificed and their aorta, left cornorary and middle cerebral arteries were dissected and morphological changes of endothelial cells studied by SEM.Results. scanning electron microscopic study of endothelial cells of aorta, left coronary and middle cerebral arteries that received lead showed morphological changes. In aorta disruption and denuation of endothelial cells, exposure of the subendothelial layer and adhesion of red blood cells, leukocytes and platelets on surface of endothelium, and presence of craters showing disrupted surface was observed. Similary endothelial cells of left coronary and middle cerebral arteries were found to show irregular orientation.Discussion. Morphologic changes of endothelial cells of aorta demonstrated that lead can cause dysfunction. In coronary and middle cerebral arteries very limited morphological changes was observed.

electron microscope is one of the best methods of analysis that is widely used in various fields. The microscope provides the possibility of examining the surface and microstructure in micron and nano dimensions. Today, one of the most specialized areas of interest is biological and living tissue. The observation of these samples and the investigation of their microstructures by scanning electron microscope require special preparation. Due to the high sensitivity of the samples, if any of the steps in the preparation are not carefully performed, it will cause shrinkage, collapse, or damage to the sample structure and will affect the quality of the final images, so it is very important that the conditions and procedures for tissue preparation carefully done with the standard method. There are many different techniques for preparing and analyzing various types of tissue that vary according to the type of tissue and structure. This paper study the general methods for the preparation of biological samples and living tissues including: a) various fixations (chemical fixtaion and physical fixation), (b) dehydration with different percentages of alcohol, and (c) different drying methods In air, critical point dryers, freeze dryers and chemical dryers), in order to view the biological structures in the closest to their living structure in a high resolution SEM is discussed.

Single-electron transistors (SETs) are one of the most basic single electron tools and have received much attention in the field of nanoelectronics. These types of transistors have very low consumption power, high performance speed, low conductivity losses, good controllability and the ability to miniyator to nanometer dimensions. A single electron transistor is a nanometer switching device that controls the movement of electrons. Due to their scope of working and in order to useing this type of transistor at ambient temperature with a minimum of Coulomb oscillations, makeing of this type of transistor with small quantum islands is very important. Nowdays, with the useing of scanning tunneling microscopes (STM) and atomic force microscopy (AFM), it is possible to makeing these types of transistors with islands in the range of a few nanometers with stable Coulomb oscillations at room temperature. In this paper, the basis of the working of single electron transistor and different methods of using scanning probe microscopes in their construction will be investigated.

Focused ion beam method (FIB), as one of the most powerful equipment, has a wide range application in the field of sample preparation, inspection and processing of equipment and machining in various fields such as semiconductors, metals, ceramics, polymers and life sciences. On the other hand, scanning electron microscopy is one of the strategic tools for advancing, analyzing and investigating researches especially in the nano fields. By studying morphology, topography, phase structures and chemical compounds, it can provide comprehensive information on the types of samples. Nowadays, in order to improve the efficiency, it is possible to investigation three-dimensional structures on the micro and nano scale, the possibility of studying on the site, the possibility of preparing sequential films and the ability to create images and control all the machining and preparation steps of the samples, a combination of these two techniques in the field of research, the technique of focused ion beam-scanning electron microscopy (FIB-SEM) has been presented. Due to the expansion of Nano scale research and industrial projects and the increasing need for advanced equipment to investigate and analyze them, the FIB-SEM technique, as one of the most fundamental diagnostic devices It is very important. Therefore, in this paper, the structure, function, and some of the applications of this technique are investigated.

The difficulties and limitations of imaging with scanning electron microscopy in high vacuum with some samples lead to manufacturing Environmental scanning electron microscope (ESEM) or special detectors with the ability to work in low vacuum conditions. The vacuum rate inside the chamber in high vacuum SEMs, is approximately [10-3] Pa. The imaging in this condition could be done with appropriate quality. But despite of sputtering thick layer of golden coat, in some nonconductive specimens like Hydroxyapatite and porous Nano Silica, charging effect commonly occurs because of the porosity of the material. Some samples like organic wastes, pastes, binders (like oils), lubricants and other additives may be evaporated in high vacuum and imaging process will get into trouble. Also low vacuum usually is applied for biological samples and scaffolds due to their deformation in high vacuum.