Microwave-assisted preparation of a silver nanoparticles/N-doped carbon dots nanocomposite and its application for catalytic reduction of rhodamine B,methyl red and 4-nitrophenol dyes

In the current work, a silver nanoparticles/nitrogen-doped carbon dots (AgNPs/NCDs) nanocomposite was prepared by a microwave-assisted method that does not require additional reducing or stabilizing agents. Multiple analytical techniques were used to characterize the prepared nanocomposite. The nanocomposite exhibited a surface plasmon resonance (SPR) absorption peak at 420 nm, indicating the development of AgNPs with NCDs. Further, HRTEM results confirmed the formation of the nanocomposite with the appearance of lattice fringes of both materials. Additionally, the nanocomposite did not show any precipitation even after two months of storage. The nanocomposite exhibited high catalytic activity towards the reduction of rhodamine B (RhB, 98.83%), methyl red (MR, 97.14%) and 4-nitrophenol (4-NP, 99.95%) at ambient temperature. Besides, the kinetic analysis revealed that the reduction reaction followed pseudo-first-order kinetics and the calculated rate constants (k) for rhodamine B (RhB), methyl red (MR) and 4-nitrophenol (4-NP) were found to be 0.0296 s⁻¹, 0.0233 s⁻¹ and 0.029 s⁻¹, respectively. Moreover, it is a reusable and stable catalyst for reduction reactions up to five cycles without significant loss in catalytic activity. Finally, a plausible mechanism for the reduction of pollutants is also discussed in detail. As a whole, the prepared nanocomposite might display stunning behaviour for wastewater treatment applications.

A silver nanoparticles/nitrogen-doped carbon dots (AgNPs/NCDs) nanocomposite was prepared by a microwave-assisted method, and exhibited high catalytic activity towards the reduction of rhodamine B, methyl red and 4-nitrophenol at ambient temperature.     

Synthesis and characterization of a new ZIF-67@MgAl2O4 nanocomposite and its adsorption behaviour

Fabricating suitable adsorbents with low-cost and high efficiency extraction for measurement of very small amounts of agricultural pesticides in food and water is playing a vital key role in personal and environmental health. Here, a new composite of zeolitic imidazolate framework-67@magnesium aluminate spinel (ZIF-67@MgAl₂O₄) has been fabricated by a simple method at room temperature with different weight ratios. Several techniques such as FE-SEM, BET, XRD, and TGA have been used to confirm the structural characterization of the obtained materials. The obtained ZIF-67@MgAl₂O₄ was utilized as an adsorbent in the solid phase microextraction technique to extract and preconcentrate the herbicide molinate (as an analyte) in aqueous solution. Corona discharge ionization-ion mobility spectrometry (CD-IMS) was applied for quantification of the analyte molecules. Extraction temperature, extraction time, stirring rate, and sample pH as the main parameters that affected the extraction proficiency were chosen and considered. Under optimal conditions, the linear dynamic range (LDR) of the various concentrations of the molinate and correlation coefficient were 10.0–100.0 μg L⁻¹ and 0.9961, respectively. The limit of quantification (LOQ) and method detection limit (MDL) were 10.0 μg L⁻¹ and 3.0 μg L⁻¹, respectively. The relative standard deviation (RSD) of the ZIF-67@MgAl₂O₄ for extracting the molinate molecules (molinate concentration; 50 μg L⁻¹) was calculated to be 4% and the enrichment factor (EF) was ∼5.

New nanocomposite of zeolitic imidazolate framework-67@magnesium aluminate spinel (ZIF-67@MgAl₂O₄) has been fabricated by a simple method at room temperature with different weight ratios.     

Vicinal halo-trifluoromethylation of alkenes

Both trifluoromethyl and halide groups are widely found in medicinally and pharmaceutically important compounds and, moreover, organohalides are commonly used as versatile intermediates in synthetic organic chemistry. Due to their prevalence and easy accessibility, alkene halo-trifluoromethylation provides a convenient way to install these valuable functionalities in complex targets. In this review, we summarize recent advances and achievements in this fast-growing research field. For clarity, the reactions were classified according to the type of halogen atom.

Both trifluoromethyl and halide groups are widely found in medicinally and pharmaceutically important compounds and, moreover, organohalides are commonly used as versatile intermediates in synthetic organic chemistry.     

Preparation of ciprofloxacin-coated zinc oxide nanoparticles and their antibacterial effects against clinical isolates of Staphylococcus aureus and Escherichia coli

In the present research study, ciprofloxacin-coated zinc oxide nanoparticles were prepared using a precipitation method. The nature of interactions between zinc oxide nanoparticles and ciprofloxacin (CAS 85721-33-1) was studied by Fourier transform infrared spectroscopy. The results show that the carbonyl group in ciprofloxacin is actively involved in forming chemical--rather than physical--bonds with zinc oxide nanoparticles. Also the antibacterial activity of free zinc oxide nanoparticles and ciprofloxacin-coated zinc oxide nanoparticles have been evaluated against different clinical isolates of Staphylococcus aureus and Escherichia coli. The free zinc oxide nanoparticles did not show potent antibacterial activity against all test strains. In contrast, only the low concentrations of ciprofloxacin-coated zinc oxide nanoparticles (equivalent to the sub-minimum inhibitory concentrations of pure ciprofloxacin) considerably enhanced the antibacterial activity of zinc oxide nanoparticles against different isolates of Staphylococcus aureus and Escherichia coli (4 to 32 fold increase). The result is of particular value, since it demonstrates that, by using biocompatible zinc oxide nanoparticles in combination therapy, lower amounts of antibiotics may be needed.     

Reassortment of Human Rotavirus Gene Segments into G11 Rotavirus Strains

G11 rotaviruses are believed to be of porcine origin. However, a limited number of G11 rotaviruses have been recently isolated from humans in combination with P[25], P[8], P[6], and P[4]. To investigate the evolutionary relationships of these strains, we analyzed the complete genomes of 2 human G11P[25] strains, 2 human G11P[8] strains, and 3 porcine reference strains. Most of the 11 gene segments of these 7 strains belonged to genotype 1 (Wa-like). However, phylogenetic clustering patterns suggested that an unknown G11P[25] strain with a new I12 VP6 genotype was transmitted to the human population, in which it acquired human genotype 1 gene segments through reassortment, resulting in a human G11P[8] rotavirus strain with an entire human Wa-genogroup backbone. This Wa-like backbone is believed to have caused the worldwide spread of human G9 and G12 rotaviruses. G11 human rotavirus strains should be monitored because they may also become major human pathogens.     

Awareness about Breast Cancer and Its Screening among Rural Egyptian Women,Minia District: a Population-Based Study

Background: Recent global cancer statistics indicate rising global incidence of breast cancer and the increase is occurring at a faster rate in developing countries. Training women how to carry out breast self-examination (BSE) can help them to be alert to any abnormalities in their breasts to speedily seek medical consultation. Health behavior may be influenced by level of awareness about breast cancer. Methods: A cross-sectional community- based study aimed to assess the level of knowledge about breast cancer risk factors, early warning signs, screening approaches and related predictors. Also, to determine the extent of practice of breast self- examination (BSE) among rural women, Minia in the period from February to May 2016. A total of 600 women were randomly included in the study. A questionnaire included socio-demographic characteristics and information related to their knowledge about breast cancer. Data analysis was carried out using SPSS version 19. Results: Moderate and high knowledge scores were presented by 46.9 %. Nearly 40% of participants had the knowledge that smoking increased the likelihood of cancer breast and almost 30% of them affirmed that being obese or having a positive family history of cancer breast made them vulnerable to cancer breast. It was found that 28.7% and 18.2% of them knew that aging and nulliparity increased the likelihood of breast cancer. Participants with better knowledge score were 4.8 times more likely to practice BSE. Conclusion: This study revealed poor knowledge among rural women regarding cancer breast. BSE and clinical breast examination were not well practiced. It is recommended to create awareness programs about breast cancer and regular patterns of BSE.     

Spectrophotometric determination of ciprofloxacin, enrofloxacin and pefloxacin through charge transfer complex formation.

A spectrophotometric method was described for the determination of the antibacterial quinolone derivatives, ciprofloxacin, enrofloxacin and pefloxacin through charge transfer complex formation with three different acceptors. Chloranilic acid (CL) was utilized for their determination, forming charge transfer complex with lambdamax 520 nm. The proposed method was applied for determination of Ciprocin tablets, Enroxil oral solution, Peflacin ampoules and Peflacin tablets, with mean percentage accuracies, 99.58+/-1.25,99.94+/-0.96,100.91+/-1.59 and 99.86+/-1.003. Also, tetracyanoethylene (TCNE) was utilized in the determination of the concerned compounds forming charge transfer complexes with maximum absorbances at lambdamax 335 nm for ciprofloxacin and at lambdamax 290 nm for both enrofloxacin and pefloxacin. The procedure was applied for determination of Ciprocin tablets, Enroxil 10% oral solution, Peflacine tablets and Peflacine ampoules with mean percentage accuracies 99.40+/-1.27,99.95+/-0.90,98.98+/-1.565 and 99.88+/-0.998, respectively. Also, 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) was utilized for determination of pefloxacin forming charge transfer complex with maximum absorbance at lambdamax 460 nm. The procedure was applied for determination of peflacine tablets and peflacine ampoules with mean percentage accuracies 100.40+/-0.76 and 99.91+/-0.623, respectively. Statistical analysis of the obtained results showed no significant difference between the proposed method and other official and reported methods as evident from the t-test and variance ratio.