The Effect of Raw Materials Molar Ratio in Mechanochemical Synthesis of Amorphous Fe-B Alloy Nanoparticles

In this study, amorphous iron-boron alloy nanoparticles successfully synthesized by mechanochemical method. The raw materials were ferrous sulfate heptahydrate (FeSO4.7H2O) as a source of iron and sodium borohydride (NaBH4) as a reducing agent. Powders grinding was performed with different NaBH4/FeSO4.7H2O molar ratio. The results revealed that high active and completely amorphous particles could be synthesized with the molar ratio of 4:1 for NaBH4:FeSO4 in 10 minutes of grinding time. Various characterizations, such as the chemical analysis, atomic absorption spectroscopy (AAS), fourier transform infrared spectroscopy (FT-IR), x-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) have been performed. The XRD results confirmed the formation of the amorphous phase. Other results also indicate the formation of amorphous alloy nanoparticles with an average particle size below 50 nm and the composition was Fe-10 Wt percent B. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3489

Designer Exosomes: A New Platform for Biotechnology Therapeutics

Abstract: Desirable features of exosomes have made them a suitable manipulative platform for biomedical applications, including targeted drug delivery, gene therapy, cancer diagnosis and therapy, development of vaccines, and tissue regeneration. Although natural exosomes have various potentials, their clinical application is associated with some inherent limitations. Recently, these limitations inspired various attempts to engineer exosomes and develop designer exosomes. Mostly, designer exosomes are being developed to overcome the natural limitations of exosomes for targeted delivery of drugs and functional molecules to wounds, neurons, and the cardiovascular system for healing of damage. In this review, we summarize the possible improvements of natural exosomes by means of two main approaches: parental cell-based or pre-isolation exosome engineering and direct or post-isolation exosome engineering. Parental cell-based engineering methods use genetic engineering for loading of therapeutic molecules into the lumen or displaying them on the surface of exosomes. On the other hand, the post-isolation exosome engineering approach uses several chemical and mechanical methods including click chemistry, cloaking, bio-conjugation, sonication, extrusion, and electroporation. This review focuses on the latest research, mostly aimed at the development of designer exosomes using parental cell-based engineering and their application in cancer treatment and regenerative medicine. Graphic Abstract: Figure not available: see fulltext. © 2020, Springer Nature Switzerland AG

Ultrasonic Findings of Intraventricular Hemorrhage in Preterm Newborns in Shariati Hospital (1391-1392)

Background and Objective: Intracranial hemorrhage (ICH) can affect newborn of all gestational ages and often is clinically silent. Germinal matrix hemorrhage and intraventricular hemorrhage (GM-IVH) is most common in the premature population. Estimated of frequency have changed over the last 20 years. Currently, large series report a 15% prevalence in infants 1250g at birth Material and Methods: All the newborns whom met the inclusion criteria were included in the study, they all had a brain sonography in the first 48 hrs after, and in case of finding any abnormality sonography was performed every week until discharge. For those who had a normal sonography, no further sonography was performed an expert pediatric radiologist performed the sonographies in sagittal and coronal planes the size of corpus collosum, lateral ventricles, inter hemispheric fissure and subarachnoid spaces were measured. (My lab 70 Esaote) Abnormal cystic regions in white and grey matter were evaluated and abnormal findings were documented. Results: Finally, 100 cases were included in the study GMH had a frequency of 28(28%) in our study. Among those with GMH 18 were male and 10 were female. There were no significant differences between the two sex groups in this regard. (P value=0.5.2), 7 of these infants were delivered through normal vaginal delivery and 21 through c/section. There was no significant difference between the two groups in this regard. (p value=0.010). Mean gestational age among the group with positive history of bleeding was 29 weeks and 31 weeks among those with negative history of bleeding. (p value=0.005). Mean birth weight with positive history of bleeding was 1292 gr and 1490 gr with no bleeding. (p value=0.035) in both groups the highest frequency belonged to first time pregnancies. (p value=0.667). Regarding the grade of bleeding, grade I with 23 cases (82.1%) had the highest frequency, grade 3 and 4 each had cases (7.1%) and grade 2 had 1 cases (3.6%). Regarding the frequency of PVL, only 6 infants (6%) had cystic PVL were detected. Conclusion: The prevalence of IVH in our study was close to other studies conducted in Iran, but was significantly higher than the western studies. Also studies showed that the prevalence of IVH decreased during to higher quality of perinatal care and delivery.&nbsp

Adoption of New Seed Varieties Under Production Risk: An Application to Rice in Iran

This paper focuses on linkage between new rice seed varieties and production risk and also factors affecting adoption of these varieties in Iran. Farm-level data were collected from a sample of 154 rice farms located in two major districts of Fars province in Southern Iran for 2001-02. The risk-premium associated with the use of seed is estimated following by analyzing a moment-based production risk approach. The results show that the risk premium increases with new seed varieties in the lack of appropriate production conditions implying that new seed varieties is a riskincreasing input and involves a higher cost of risk. However, under suitable production conditions, the cultivation of new rice varieties on average ensures greater yield and at the same time involves less risk as measured by the risk premium. Also, results indicate that the farmer-specific relative risk premium proxies for the risk attitudes of each farmer have negative and significant effect on the decision to adopt new seed varieties. Therefore, farmers that are more riskaverse with respect to their use of seed are less likely to adopt new seed varieties and allow them to decrease their production risk arising from seed requirements

An assessment of the relationship between the meta-cognitive awareness of reading strategies and students\' achievement in Iran University of Medical Sciences in 2012-2013

Introduction: Achieving meaningful learning is an important educational goal of medical students. Therefore, it is necessary to design and implement more effective methods and strategies to achieve the goal. This study aims to investigate the relationship between the meta-cognitive awareness of reading strategies in student and their achievement in Iran University of Medical Sciences. Methods : This cross sectional- analytic study was carried out on students of Iran University of Medical Science during the 2012-2013 academic years. Three hundred seventeen students were selected through stratified random sampling from all students studied in basic sciences, physiopathology and clerkship stages of the medical program. The tool used was meta-cognitive awareness of reading strategies Inventory (MARSI). Data were analyzed by SPSS 16 software and Pearson correlation-coefficients, variance analysis tests and independent T-tests were administered. Results: In this study the mean score of medical students' awareness of reading strategies showed optimal situation, the mean score of medical students' awareness of reading strategies and its three categories showed a significant relationship with students' score of academic achievement. Conclusion: Based on our findings it is concluded the medical students awareness of planning strategy and setting the purpose of reading have more influence on academic achievement than meta-cognition strategies, therefore medical education curriculum should be emphasized on these strategies to empower medical students to be independent in learning and to be self-regulating in their learning process