Magnetic cobalt ferrite nanoparticles as an efficient catalyst for oxidation of alkenes

AbstractCobalt ferrite magnetic nanoparticles with mean sizes of 25 nm were used as a catalyst for the oxidation of various alkenes in the presence of tert- butylhydroperoxide (t-BuOOH). This study has demonstrated that CoFe2O4 nanoparticles can act as an efficient catalyst for the conversion of alkenes to the related aldehydes or epoxides, with almost quantitative yields. The catalyst can be readily isolated by using an external magnet and no obvious loss of activity was observed when the catalyst was reused in five consecutive runs. The effects of some parameters, such as temperature, types of oxidant and solvents, on the oxidation reactions were also investigated. The results showed that when CoFe2O4 is used with t-BuOOH as oxidant for the oxidation of some alkenes, better results are obtained compared to most of the studied similar ferrites

Assembling thefacebook: Using heterogeneity to understand online social network assembly

Online social networks represent a popular and diverse class of social media systems. Despite this variety, each of these systems undergoes a general process of online social network assembly, which represents the complicated and heterogeneous changes that transform newly born systems into mature platforms. However, little is known about this process. For example, how much of a network's assembly is driven by simple growth? How does a network's structure change as it matures? How does network structure vary with adoption rates and user heterogeneity, and do these properties play different roles at different points in the assembly? We investigate these and other questions using a unique dataset of online connections among the roughly one million users at the first 100 colleges admitted to Facebook, captured just 20 months after its launch. We first show that different vintages and adoption rates across this population of networks reveal temporal dynamics of the assembly process, and that assembly is only loosely related to network growth. We then exploit natural experiments embedded in this dataset and complementary data obtained via Internet archaeology to show that different subnetworks matured at different rates toward similar end states. These results shed light on the processes and patterns of online social network assembly, and may facilitate more effective design for online social systems.Comment: 13 pages, 11 figures, Proceedings of the 7th Annual ACM Web Science Conference (WebSci), 201

The effect of hydro-alcoholic extract of celery (Apium graveolens) leaves on serum level of testosterone, FSH and LH in male rats

Background and Objective: Celery (Apium graveolens) is a plant from Apiaceae family with high nutritional and medicinal use.This plant has many phytoestrogens that can affect the pituitary-gonadal axis. The purpose of this study was to investigate the effect of hydro-alcoholic extract of celery leaves on serum level of testosterone, FSH and LH in male rats. Materials and Methods: In this experimental study, thirty-two male wistar rats were randomly divided into four groups of eight rats each. The control group did not receive anything. The sham group received distilled water (as a solvent), and the experimental groups received doses of 200 and 300 mg/kg/ BW of hydro-alcoholic extract of celery leaves for 20 days. The extract was gavaged once a day. One day after the last gavage, the rats were anaesthetized and blood samples were collected from the heart and then serum levels of testosterone, LH and FSH were measured. The data were analyzed using SPSS software and ANOVA test. Results: Concentration of LH in the treatment group with doses of 200 mg/kg (0.39±0.02 mIU/dl) reduced in comparison with control (0.67±0.01 mIU/dl) and sham (0.73±0.02 mIU/dl) groups (P0.05). Conclusion: The results indicated that the administration of 200 mg/kg doses of celery extract causes a significant reduction in serum LH concentration, but it has no effect on ganadotropin and testosterone hormones in highest doses used in this study. This finding may be due to the presence of flavonoid and antioxidant proporties of celery

Competition and Selection Among Conventions

In many domains, a latent competition among different conventions determines which one will come to dominate. One sees such effects in the success of community jargon, of competing frames in political rhetoric, or of terminology in technical contexts. These effects have become widespread in the online domain, where the data offers the potential to study competition among conventions at a fine-grained level. In analyzing the dynamics of conventions over time, however, even with detailed on-line data, one encounters two significant challenges. First, as conventions evolve, the underlying substance of their meaning tends to change as well; and such substantive changes confound investigations of social effects. Second, the selection of a convention takes place through the complex interactions of individuals within a community, and contention between the users of competing conventions plays a key role in the convention's evolution. Any analysis must take place in the presence of these two issues. In this work we study a setting in which we can cleanly track the competition among conventions. Our analysis is based on the spread of low-level authoring conventions in the eprint arXiv over 24 years: by tracking the spread of macros and other author-defined conventions, we are able to study conventions that vary even as the underlying meaning remains constant. We find that the interaction among co-authors over time plays a crucial role in the selection of them; the distinction between more and less experienced members of the community, and the distinction between conventions with visible versus invisible effects, are both central to the underlying processes. Through our analysis we make predictions at the population level about the ultimate success of different synonymous conventions over time--and at the individual level about the outcome of "fights" between people over convention choices.Comment: To appear in Proceedings of WWW 2017, data at https://github.com/CornellNLP/Macro

Seroprevalence of cytomegalovirus among women of reproductive age in iran: A systematic review and meta-analysis

Background: Human cytomegalovirus (CMV) able to cause infection for an entire lifetime. This systematic review and meta-analysis was conducted to determine seroprevalence of CMV among women of reproductive age in Iran. Methods: English and Persian databases such as Web of Science (WOS), PubMed, Scopus, Cochrane Library, SID, Iran doc, Iran Medex, Magiran, and Medlib were searched (from 2008 to 2017) accurately using the keywords: Cytomegalovirus, Pregnant women or Pregnancy, Epidemiology, Prevalence and Iran. Results: Results of 15 studies with total samples of 5253 persons from 2008 to 2017 were combined and meta-analyzed. The pooled prevalence rate of IgG among women was estimated 90 (95 CI: 87-93). The highest prevalence rate of IgG was in Tehran, Rasht, Mashhad and Yasoj, all 100 (95 CI: 100-100), and the lowest prevalence was in Jahrom 0.62 (95 CI: 53-71). The overall prevalence rate of IgM among women was estimated at 0.06 (95 CI: 0.03-0.13). The highest prevalence rate of IgM was in Kerman 0.34 (95 CI: 0.29-0.39) and Mashhad 0.25 (95 CI: 0.2-0.31), and the lowest prevalence was in Yasoj 0 (95 CI: 0.00-0.00) Conclusion: The prevalence of immunity in Iran, is satisfactory. Nevertheless, to maintain and increase the level of immunity across the country, it is necessary to routinely screen the women of reproductive ages across the country. © 2019, Iranian Journal of Public Health. All rights reserved

Prevalence rate of hepatitis B virus in pregnancy: Implications from a systematic review and meta-analysis of studies published from 2000 to 2016

Background: Hepatitis B Virus (HBV) is one of the most serious infectious diseases and represents a major global health issue worldwide. It can be transmitted vertically and horizontally through contact with infected blood or body fluids. More attention to HBV infection in pregnancy is needed due to high risk of chronicity when transmitted to infants during delivery. Objectives: A comprehensive review of the HBV prevalence rate in pregnant females taking into account different geographical areas and socio-economic status is still lacking. This would be of crucial importance for HBV prevention and control programs. As such, this systematic review and meta-analysis was conducted focusing on HBV prevalence rate in pregnant females from different parts of the world. Methods: Different electronic databases, including Embase, PubMed/MEDLINE, Scopus, and ISI/Web of Science were searched from January 1st 2000 to July 31st 2016, using relevant keywords, such as �prevalence� or �seroprevalence� or �epidemiology� and �pregnancy� or �pregnant� or �antenatal� in combination with �hepatitis B virus� or �HBV� with no language restrictions. The study protocol of this systematic review was deposited at the �International Prospective Register of Systematic Reviews� and registered as CRD42016041985. Results: After scrutinizing all the extant scholarly literature from 2000 to 2016, this study found 222 relevant articles. The overall HBV prevalence rate in pregnant females worldwide was estimated using a random-effect model, giving a value of 3 (95 confidence interval or CI 2 - 4). Heterogeneity between studies was significantly high (I2 = 99.9, P < 0.0001). The clinical and epidemiological burden was higher in developing countries. Conclusions: This suggests that despite the recent scientific advancements and the clinical progress that has occurred in anti-viral therapy, HBV still represents a major issue worldwide, especially in underdeveloped countries. The key strategies for preventing transmission from pregnant females to their fetuses are through early birth dose and infant vaccination, as well as by the use of hepatitis B immunoglobulin (HBIG) and the screening and diagnosis of mothers at high risk and the subsequent use of anti-viral agents during pregnancy in order to reduce maternal DNA concentrations down to undetectable concentrations. Health authorities should effectively implement these approaches to better control HBV in pregnancy. © 2018, Hepatitis Monthly

Prevalence rate of hepatitis B virus in pregnancy: Implications from a systematic review and meta-analysis of studies published from 2000 to 2016

Background: Hepatitis B Virus (HBV) is one of the most serious infectious diseases and represents a major global health issue worldwide. It can be transmitted vertically and horizontally through contact with infected blood or body fluids. More attention to HBV infection in pregnancy is needed due to high risk of chronicity when transmitted to infants during delivery. Objectives: A comprehensive review of the HBV prevalence rate in pregnant females taking into account different geographical areas and socio-economic status is still lacking. This would be of crucial importance for HBV prevention and control programs. As such, this systematic review and meta-analysis was conducted focusing on HBV prevalence rate in pregnant females from different parts of the world. Methods: Different electronic databases, including Embase, PubMed/MEDLINE, Scopus, and ISI/Web of Science were searched from January 1st 2000 to July 31st 2016, using relevant keywords, such as �prevalence� or �seroprevalence� or �epidemiology� and �pregnancy� or �pregnant� or �antenatal� in combination with �hepatitis B virus� or �HBV� with no language restrictions. The study protocol of this systematic review was deposited at the �International Prospective Register of Systematic Reviews� and registered as CRD42016041985. Results: After scrutinizing all the extant scholarly literature from 2000 to 2016, this study found 222 relevant articles. The overall HBV prevalence rate in pregnant females worldwide was estimated using a random-effect model, giving a value of 3 (95 confidence interval or CI 2 - 4). Heterogeneity between studies was significantly high (I2 = 99.9, P < 0.0001). The clinical and epidemiological burden was higher in developing countries. Conclusions: This suggests that despite the recent scientific advancements and the clinical progress that has occurred in anti-viral therapy, HBV still represents a major issue worldwide, especially in underdeveloped countries. The key strategies for preventing transmission from pregnant females to their fetuses are through early birth dose and infant vaccination, as well as by the use of hepatitis B immunoglobulin (HBIG) and the screening and diagnosis of mothers at high risk and the subsequent use of anti-viral agents during pregnancy in order to reduce maternal DNA concentrations down to undetectable concentrations. Health authorities should effectively implement these approaches to better control HBV in pregnancy. © 2018, Hepatitis Monthly

Perspectives of the Apiaceae Hepatoprotective Effects - A Review

The liver has the crucial role in the regulation of various physiological processes and in the excretion of endogenous waste metabolites and xenobiotics. Liver structure impairment can be caused by various factors including microorganisms, autoimmune diseases, chemicals, alcohol and drugs. The plant kingdom is full of liver protective chemicals such as phenols, coumarins, lignans, essential oils, monoterpenes, carotenoids, glycosides, flavonoids, organic acids, lipids, alkaloids and xanthenes. Apiaceae plants are usually used as a vegetable or as a spice, but their other functional properties are also very important. This review highlights the significance of caraway, dill, cumin, aniseed, fennel, coriander, celery, lovage, angelica, parsley and carrot, which are popular vegetables and spices, but possess hepatoprotective potential. These plants can be used for medicinal applications to patients who suffer from liver damage