Spin Hall effect of vorticity

Using mapping between topological defects in an easy-plane magnet and electrical charges, we study interplay between vorticity and spin currents. We demonstrate that the flow of vorticity is accompanied by the transverse spin current generation; an effect which can be termed as the spin Hall effect of vorticity. We study this effect across the BKT transition and establish the role of dissipation and spin nonconservation in the crossover from spin superfluidity to diffusive spin transport. Our results pave the way for low power computing devices relying on vorticity and spin flows that can propagate over long distances

Majorana Bound States in a \u3ci\u3ed\u3c/i\u3e-wave Superconductor Planar Josephson Junction

We study phase-controlled planar Josephson junctions comprising a two-dimensional electron gas with strong spin-orbit coupling and d-wave superconductors, which have an advantage of a high critical temperature. We show that a region between the two superconductors can be tuned into a topological state by the in-plane Zeeman field, and can host Majorana bound states. The phase diagram as a function of the Zeeman field, chemical potential, and the phase difference between superconductors exhibits the appearance of Majorana bound states for a wide range of parameters. We further investigate the behavior of the topological gap and its dependence on the type of d-wave pairing, i.e., d, d + is, or d + id\u27, and note the difficulties that can arise due to the presence of gapless excitations in pure d-wave superconductors. On the other hand, the planar Josephson junctions based on superconductors with d + is and d + id\u27 pairings can potentially lead to realizations of Majorana bound states. Our proposal can be realized in cuprate superconductors, e.g., in a twisted bilayer, combined with the layered semiconductor Bi2O2Se

Majorana bound states in d-wave superconductor planar Josephson junction

We study phase-controlled planar Josephson junction comprising a two-dimensional electron gas with strong spin-orbit coupling and d-wave superconductors, which have an advantage of high critical temperature. We show that a region between the two superconductors can be tuned into topological state by the in-plane Zeeman field, and can host Majorana bound states. The phase diagram as a function of the Zeeman field, chemical potential, and the phase difference between superconductors exhibits the appearance of robust Majorana bound states for a wide range of parameters. We further investigate the behavior of the topological gap and its dependence on the type of d-wave pairing, i.e., d, d+is, or d+id', and note the difficulties that can arise due to the presence of gapless excitations in pure d-wave superconductors. On the other hand, the planar Josephson junctions based on superconductors with d+is and d+id' pairings can potentially lead to realizations of Majorana bound states. Our proposal can be realized in twisted bilayer d-wave superconductors realizable in mechanically exfoliated van der Waals copper oxide heterostructures.Comment: 4 pages, 4 figure

Antimicrobial Activity of Marine Actinomycetes and the Optimization of Culture Conditions for the Production of Antimicrobial Agent(s)

The aim of the present study was to isolate antagonistic actinomycetes from marine sediment collected from the Red Sea coast at Hurghada city and the Suez Gulf. A total of 16 actinomycete isolates were obtained in October 2018 and their antagonistic activities were evaluated against Aeromonas hydrophila, Vibrio damsela, Staphylococcus aureus ATCC6538, Bacillus subtilis ATCC 6633, Pseudomonas aeruginosa ATCC 9027, Salmonella typhimurium ATCC 14028, Escherichia coli ATCC 19404 and Candida albicans ATCC 10231 by using the agar well diffusion method. Among the 16 isolates, 14 (87.5%) isolates exhibited antimicrobial activity against most of the tested pathogens. The most potent isolate was identified by 16S rRNA sequence analysis as Streptomyces sp. and designated Streptomyces sp. MK388207. The experimental design of Plackett-Burman was implemented to optimize the culture conditions for antimicrobial agent(s) production by the most powerful isolate against C. albicans ATCC 10231 when grown in starch nitrate broth and the data revealed that negative (–) levels of KNO3, K2HPO4 and pH and positive (+) levels of starch, MgSO4.7H2O, FeSO4 and incubation period supported the production of the antimicrobial agent(s). Growth under the optimized culture conditions led to a 1.4-fold rise in antimicrobial activity. The ethyl acetate extract of Streptomyces sp.MK388207 was subjected to gas-liquid chromatography mass spectrometry (GC MS) and revealed the presence of six fractions with the major component being phenol, 2,4-bis (1,1 dimethylethyl). The findings of this study suggested that the antagonistic marine Streptomyces, in particular Streptomyces sp MK388207, the antibacterial compounds produced by this isolate, could be used as antibiotics that could have future applications in the pharmaceutical industry

Production and Characterization of Extracellular Polymeric Substances by marine Halomonas sp. NASH isolated from Wadi El-Natroun

Halophilic micro-organisms often synthesize and produce extracellular polysaccharides (EPS), whose physical, chemical properties and material properties vary greatly from each other. The extracellular polysaccharide (EPS) development of Halomonas sp. MN795630 strain type halophilic bacterium (NASH) was investigated and whether biotechnological applications were feasible. After 168 hours of incubation, 4 g/L of EPS was produced and all elements from the medium were completely used during the growth. Sucrose has been identified as the most favorable carbon source for production of EPS and maximum production (6 g/l). Beef extract level was shown to be the best for EPS production among different nitrogen sources. Optimum production of EPS (10 g/L) were achieved by supplementing the medium with 4M NaCl, pH adjusted at 9 and the medium was inoculated with 7% initial inoculum. The purified EPS were characterized chemically. Fourier transform infrared (FTIR) spectrophotometer was observed in several functional groups. EPS also demonstrated an significant inhibitor of Candida albicans ATCC 10231 and Pseudomonas aeruginosa ATCC 9027 (20.4 and 14.7 mm), respectively. EPS show satisfactory results when applied as anti-oxidant, anti-inflammatory and emulsifier

Antibacterial and anticancer activity of marine Streptomyces parvus: optimization and application

A total of 17 actinomycetes were isolated and screened against five bacterial pathogens. Forty-one per cent of the isolates were active against the tested pathogens. The most potent isolate was identified as Streptomyces parvus by using a 16S rRNA sequence analysis. S. parvus produced active compound(s) against a number of Gram negative and Gram positive bacteria. The obtained inhibition zones were 14, 19, 20 and 20 mm against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Aeromonas hydrophila, respectively. Moreover, the anticancer activity of S. parvus was tested against four different cell lines: human liver cancer cell line, mouse lymphoma cell line, breast cancer cell line and human colon cancer cell line. The inhibition activities were 53%, 56%, 57% and 42%, respectively. To achieve a maximum production of the bioactive compound, Plackett–Burman design was applied. The productivity increased up to 1.3-fold, when S. parvus was grown in optimized medium composed of: 10 g L−1 starch, 1.5 g L−1 KNO3, 0.75 g L−1 K2HPO4, 0.75 g L−1 MgSO4∙7H2O, 0.015 g L−1 FeSO4, 2 mL (103 colony-forming units mL−1) inoculum size with pH 8 for 7 d of incubation. The main constitutes of S. parvus crude extract were determined by gas–liquid chromatography mass spectrometry. They were found to be ethane, 1,1-diethoxy; di-n-octyl phthalate; ethanol, 2,2-diethoxy; 9,12-octadecadienoic acid; methyl ester (E,E) and benzoic acid

Antibacterial and anticancer activity of extracellular synthesized silver nanoparticles from marine Streptomyces rochei MHM13

The study investigated silver nanoparticles (AgNPs) synthesized extracellularly using an actinomycete isolated from sediment of the Suez Gulf, Red Sea, Egypt. Screening for biosynthesis of AgNPs revealed that among the forty one actinomycetes tested, only two exhibited the ability to synthesize AgNPs with antibacterial activit

Papaya fruit by-products as novel food ingredients in cupcakes

Large quantities of waste generated from papaya fruit processing, especially seeds, can be recovered and combined to obtain added-value products. This investigation aimed to evaluate the physicochemical properties and antimicrobial activity of papaya seed powder (PSP) and papaya seed oil (PSO), and their applications as novel nontraditional food ingredients in cupcakes to promote them as high-value products. The GC–MS analysis for PSP revealed 39 compounds possess various biological activities, indicating the safety of its consumption. Papaya seeds are an excellent source of protein (27.95 %), oil (31.83 %), ash (7.86 %) and fibers (18.53 %). They have the potential to produce high-quality oleic oil with highly similar physicochemical properties and fatty acids profile as olive oil. The broad-spectrum inhibition of PSP and PSO against the tested pathogens proved their potential as natural antimicrobial agents. PSP can successfully be used (as nutritive ingredients and antimicrobial agents) in combination with wheat flour to obtain delicious and healthy nutritious chocolate cupcakes. The supplemented cupcakes (up to 15 % level) had improved quality attributes and enhanced nutritional value with respect to protein (16.89 %), ash (4.17 %) and fibers (3.28 %). PSP and PSO are safety, edible, nutritious, antimicrobial and can be processed into value-added products. They can be used as novel functional food ingredients or natural additives, providing added value to the food processing

Phytochemical Profile of the Ethanol Extract of <i>Malvaviscus arboreus</i> Red Flower and Investigation of the Antioxidant, Antimicrobial, and Cytotoxic Activities

Flowers are rich sources of bioactive antimicrobial, antioxidant, and anticancer components. This study aimed to determine the constituents of the ethanol extract of Malvaviscus arboreus red flower (ERF) by GC-MS analysis and HPLC identification of phenolic compounds and flavonoids, in addition to the 1HNMR fingerprint. The antimicrobial, antioxidant, and cytotoxic activities of the ERF were investigated. The GC-MS analysis revealed twenty-one components, while HPLC analysis revealed the presence of phenolic and flavonoid compounds. The ERF showed antifungal and antibacterial activity. The highest antibacterial activity was found against Vibrio damsela where a time-kill assay revealed a decline in the amount of viable V. damsela. For fungi, the highest activity was observed against Aspergillus terreus. Using the SRB test on HepG2, the anti-proliferative efficacy of the ERF was evaluated. Cell cycle analysis was utilized to determine autophagic cell death. The ERF prevented the proliferation of the HepG2 cell line with an IC50 of 67.182 µg/µL. The extract primarily promoted apoptosis in HepG2 cells by accumulating hypodiploid cells in the sub-G0/G1 phase, increased caspase 3/7 activity, and caused considerable autophagic cell death in apoptosis-deficient cells. Finally, the observed elevation of cancer cell death indicated that ERF had substantial anticancer potential against HepG2 cells

Biosynthesis of Copper Oxide Nanoparticles Using Streptomyces MHM38 and Its Biological Applications

Biosynthesis methods employing microorganisms have emerged as an eco-friendly, clean, and viable alternative to chemical and physical processes. The present study reports the synthesis of copper oxide nanoparticles (CuONPs) using cell-free culture supernatant of marine Streptomyces sp. MHM38. For the optimized production of CuONPs, the influence of some parameters, such as the concentration of copper sulfate (CuSO4), reaction time, filtrate to substrate ratio, and pH, was studied. 5 mM of CuSO4 was optimal for nanoparticle (NP) production. Well-defined CuONP formation occurred after 60 min of incubation when an equal volume of filtrate (cell-free supernatant) to substrate (CuSO4 solution) was added. UV-visible spectroscopy analysis of CuONPs exhibited a peak at 550 nm, which corresponds to the surface plasmon resonance of CuONPs. Most of the particles were spherical and were 1.72–13.49 nm when measured using a transmission electron microscope. The antimicrobial activity of CuONPs was determined using a well diffusion method against Enterococcus faecalis ATCC 29212, Salmonella typhimurium ATCC 14028, Pseudomonas aeruginosa ATCC 9027, Escherichia coli ATCC 8939, fungi (Rhizoctonia solani, Fusarium solani, and Aspergillus niger), and yeast (Candida albicans ATCC 10237). The highest antimicrobial activities were recorded against Candida albicans ATCC 10237, whereas Salmonella typhimurium ATCC 14028 and Escherichia coli ATCC 8939 showed the less activity. The biochemical findings of the CuONP groups were significant (p<0.05) with diminished levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), total and direct bilirubin, urea, and creatinine compared with the paracetamol group. Nonenzymatic and enzymatic antioxidants of the CuONP groups were significantly elevated (p<0.05) in SOD and GSH levels, and exceptionally low nitric oxide (NO) and malondialdehyde (MAD) levels were found for the paracetamol group. The histopathological examination of the CuONP groups assured the impact of improving CuONPs against paracetamol-induced liver damage