Effect of gamma irradiation on properties of the synthesized PANI-Cu nanoparticles assimilated into PS polymer for electromagnetic interference shielding application.

Conductive polymer nanocomposites for electromagnetic interference (EMI) shielding are important materials that can be combat the increasingly dangerous radiation pollution arising from electronic equipment and our surrounding environment. In this work, we have synthesized polyaniline-copper nanoparticles (PANI-Cu NPs) by the copper salt based oxidative polymerization method at room temperature and then added with different concentration (0, 1, 3 and 5 wt%) in polystyrene polymer forming PS/ PANI-Cu nanocomposites films by means of the traditional solution casting technique. The formed PANI-Cu NPs were investigated by UV/Vis spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM) and SEM/EDX elemental mapping techniques. On the other hand, the prepared PS/PANI-Cu nanocomposites films were evaluated by UV and SEM, the mechanical properties of the nanocomposites films were evaluated and showed an improvement by added PANI-Cu NPs up to 3 wt% and 50 kGy gamma exposure dose. The PS/PANI-Cu nanocomposites films were examined as electromagnetic interference shielding material. Electromagnetic shielding effectiveness of the produced nanocomposites were tested in the X-band of the radio frequency range namely from 8 to 12 GHz using the vector network analyzer (VNA) and a proper wave guide. All samples were studied before and after 50 kGy gamma-ray irradiation under the same condition of pressure and temperature. The results showed that the nanocomposites have improved shielding properties.

Chitosan-sulfonic acid-catalyzed green synthesis of naphthalene-based azines as potential anticancer agents.

Aim: This study focuses on advancing green chemistry in anticancer drug discovery, particularly through the synthesis of azine derivatives with a naphthalene core using CS-SO3H as a catalyst. Methods: Novel benzaldazine and ketazine derivatives were synthesized using (E)-(naphthalen-1-ylmethylene)hydrazine and various carbonyl compounds. The methods employed included thermal and grinding techniques, utilizing CS-SO3H as an eco-friendly and cost-effective catalyst. Results: The approach resulted in high yields, short reaction times and demonstrated catalyst reusability. Cytotoxicity tests highlighted compounds 3b, 11 and 13 as potent against the HEPG2-1. Conclusion: This study successfully aligns with the objectives of eco-conscious drug development in organic chemistry. Molecular docking and in silico studies further indicate the potential of these ligands as antitumor medicines, with favorable oral bioavailability properties.

Impact of gamma irradiation on physico-chemical and electromagnetic interference shielding properties of Cu2O nanoparticles reinforced LDPE nanocomposite films.

In the current work, cuprous oxide (Cu2O) nanoparticles coated with Tween 80 were successfully synthesized via the chemical reduction method. Nanocomposites composed of low-density polyethylene (LDPE) and different ratios of Cu2O nanoparticles were fabricated by the melt mixing process. 10% of ethyl vinyl acetate (EVA) as a compatibilizing agent was added to the molten LDPE matrix and the mixing process continued until homogenous nanocomposites were fabricated. To study the influence of ionizing radiation on the fabricated samples, the prepared species were exposed to 50 and 100 kGy of gamma rays. The synthesized Cu2O nanoparticles were investigated by transmission electron microscopy (TEM) and X-ray diffraction (XRD). XRD and TEM analysis illustrated the successful formation of spherical Cu2O nanoparticles with an average size of 16.8 nm. The as-prepared LDPE/Cu2O nanocomposites were characterized via different techniques such as mechanical, thermal, morphological, XRD, and FTIR. Electromagnetic interference shielding (EMI) of the different nanocomposite formulations was performed as a promising application for these materials in practical life. The electromagnetic shielding effectiveness (SE) of the produced samples was measured in the X-band of the radio frequency range from 8 to 12 GHz using the vector network analyzer (VNA) and a proper waveguide. All the samples were studied before and after gamma-ray irradiation under the same conditions of pressure and temperature. The shielding effectiveness increased significantly from 25 dB for unirradiated samples to 35 dB with samples irradiated with 100 kGy, which reflects 40% enhancement in the effectiveness of the shielding.

Genome Analysis of Pseudomonas aeruginosa Strains from Chronically Infected Patients with High Levels of Persister Formation.

The appearance of persister cells with low metabolic rates are key factors leading to antibiotic treatment failure. Such persisters are multidrug tolerant and play a key role in the recalcitrance of biofilm-based chronic infections. Here, we present the genomic analyses of three distinct Pseudomonas aeruginosa Egyptian persister-isolates recovered from chronic human infections. To calculate the persister frequencies, viable counts were determined before and after treatment with levofloxacin. The susceptibilities of isolates to different antibiotics were determined using the agar-dilution method. To determine their recalcitrance, the levofloxacin persisters were further challenged with lethal concentrations of meropenem, tobramycin, or colistin. Furthermore, the biofilm formation of the persister strains was estimated phenotypically, and they were reported to be strong biofilm-forming strains. The genotypic characterization of the persisters was performed using whole genome sequencing (WGS) followed by phylogenetic analysis and resistome profiling. Interestingly, out of the thirty-eight clinical isolates, three isolates (8%) demonstrated a persister phenotype. The three levofloxacin-persister isolates were tested for their susceptibility to selected antibiotics; all of the tested isolates were multidrug resistant (MDR). Additionally, the P. aeruginosa persisters were capable of surviving over 24 h and were not eradicated after exposure to 100X-MIC of levofloxacin. WGS for the three persisters revealed a smaller genome size compared to PAO1-genome. Resistome profiling indicated the presence of a broad collection of antibiotic-resistance genes, including genes encoding for antibiotic-modifying enzymes and efflux pump. Phylogenetic analysis indicated that the persister isolates belong to a distinct clade rather than the deposited P. aeruginosa strains in the GenBank. Conclusively, the persister isolates in our study are MDR and form a highly strong biofilm. WGS revealed a smaller genome that belongs to a distinct clade.

Investigation of physico-mechanical properties of flexible poly (vinyl chloride) filled with antimony trioxide using ionizing radiation.

Composites of polyvinyl chloride (PVC) with 2% calcium carbonate, 2% diethyl phthalate, 2% paraffin wax and 2% lead sulphate and different contents of antimony trioxide (Sb2O3) prepared by melting and irradiated with gamma ray have been considered. Assessment of the mechanical and thermal properties of the unirradiated and irradiated flexible polyvinyl chloride (FPVC) were completed utilizing elasticity (TS), Elongation at break (Eb) and thermogravimetric analysis measurements. TS and thermal stability of FPVC displayed advanced improvement after addition of additives and this approach highlighted the efficiency of those ingredients on PVC. The compounding of FPVC with Sb2O3 in various extents was examined by FTIR, X-ray diffraction and scanning electron microscope methods. It is obvious that the presence of Sb2O3 begins impacting oxidative degradation, leading to a decrease in mechanical properties up to 10%. Moreover, a slight increase in the thermal stability of composites by exposure to ionizing radiation is apparently due to cross-linking of FPVC chains.

Differentiation of pityriasis rubra pilaris from plaque psoriasis by dermoscopy.

Pityriasis rubra pilaris (PRP) and plaque psoriasis (PP) are two distinctive erythemato-squamous skin diseases that often have to be differentiated from each other and from other similar dermatoses. Dermoscopy has been proven to aid the clinical diagnosis of several inflammatory disorders, minimizing the need for skin biopsy. Our aim was to determine the dermoscopic patterns of PRP compared to PP and to assess the significance of certain dermoscopic criteria in the diagnosis of PRP. This case-control study included 11 patients with biopsy proven PRP and 25 patients with biopsy proven plaque psoriasis. The most recently developed lesion of each patient was examined by non-contact dermoscopy. Whitish keratotic plugs and linear vessels in yellowish background are significant dermoscopic features of PRP compared to white diffuse scales and dotted vessels in a light red background in PP. In conclusion, PRP and PP reveal specific distinguishing dermoscopic patterns that may assist in their clinical diagnosis and may also be useful for the differential diagnosis from other resembling dermatoses.

Experimental evaluation of anti-inflammatory, antinociceptive and antipyretic activities of clove oil in mice.

BACKGROUND: Clove oil of Eugenia caryophyllata (Myrtaceae) is a light yellowish fluid obtained from dried flower buds. Clove oil is used traditionally to relieve toothache. AIM: The aim of the present work was to study the anti-inflammatory, antinociceptive and antipyretic potential of clove oil in mice. METHODS: Analgesic activity was examined using acetic-acid-induced abdominal constrictions and the hot plate test. Carrageenan-induced paw edema and brewer's-yeast-induced pyrexia were used to investigate the anti-inflammatory activity and the antipyretic effects, respectively. The oil was administered intraperitoneally (i.p.) at a dose of 33 mg/kg body weight and the effects were compared with reference drugs. RESULTS: In the antinociceptive test, mice treated with clove oil exhibited significantly decreased acetic-acid-induced writhing movements by a maximum of 87.7% (p<0.01) compared with a decrease of 77.7% (p<0.01) in response to aspirin injection (100 mg/kg, intraperitoneal, i.p.). Similarly, in the hot plate test, clove oil significantly increased the reaction latency to pain after 60 min by 82.3% (p<0.05) compared with morphine value of 91.7% (p<0.01). In addition, clove oil and indomethacin produced anti-inflammatory effects, as demonstrated by respectively 50.6% (p<0.05) and 70.4% (p<0.01) inhibition of mouse paw edema induced by carrageenan. Furthermore, clove oil significantly attenuated the hyperthermia induced by yeast at ΔT-max by 2.7°C (p<0.001), and time of peak effects was 30-180 min compared with a paracetamol value ΔT-max of 3.2°C (p<0.001). The estimated i.p. LD50 of clove oil was 161.9 mg/kg. Phytochemical screening of the oil showed the presence of eugenol. CONCLUSION: The present findings demonstrate the potential pharmacological properties of clove oil and provide further a support for its reported use in folk medicine.

Ultrafiltration and Reverse Osmosis in Dairy Technology: A Review.

Ultrafiltration and reverse osmosis processes can be useful in the dairy foods industry. When milk is processed, milk fat and casein are rejected fully (e.g., are in retentate) and thus are concentrated by ultrafiltration and reverse osmosis membranes. Lactic cultures are slow to reduce the pH of retentate because of its increased buffering capacity since concentrated calcium phosphate and proteins are present. Conditions for growth of pathogenic microorganisms and inhibition of such bacteria in ultrafiltered milk differ from those of unfiltered milk. The principal advantage of using ultrafiltered milk for conversion into such cheeses as Cheddar, cottage, Havarti, Feta, brick, Colby, and Domiati is an increase in yield of product. Additional benefits claimed for use of ultrafiltered milk in cheese making include reduction in costs of energy, equipment, and labor; improved consistency of cheese flavor; and possible production of new byproducts.

Growth of Listeria monocytogenes at 4, 32, and 40°C in Skim Milk and in Retentate and Permeate from Ultrafiltered Skim Milk.

Pasteurized skim milk and retentate (concentrated fivefold or twofold by volume) and permeate from ultrafiltered skim milk were inoculated with Listeria monocytogenes strains California or V7 and incubated at 4, 32, or 40°C. Changes in populations of the pathogen were determined, growth curves were derived, and generation times and maximum populations calculated for each combination of strain, product, and temperature. Both strains grew faster and achieved higher (ca. 1 to 2 orders of magnitude) populations at 4°C in retentate of either concentration than in skim milk. The pathogen grew in permeate at 4°C and attained maximum populations of ca. 106 to 107/ml. Tyndallized samples of skim milk and retentate and permeate from ultrafiltered skim milk were inoculated with the same strains of L. monocytogenes and incubated at 32 or 40°C. Populations achieved by the pathogen at these temperatures, ca. 107 to 108/ml, were similar in skim milk, retentate, and permeate.

Fate of Listeria monocytogenes in Sweetened Condensed and Evaporated Milk During Storage at 7 or 21 °C.

Sweetened condensed and evaporated milks were inoculated to contain ca. 103 to 107 cells of Listeria monocytogenes (strains Scott A, California, or V7)/ml. Both inoculated products were cooled from 25°C to 21°C in ca. 2 h or to 7°C in ca. 4 h. When inoculated sweetened condensed milk was held at 7°C for 42 d, there was no appreciable decrease in numbers of L. monocytogenes strains Scott A and V7, whereas the population of L. monocytogenes strain California decreased by ca. 1.2 orders of magnitude. Inoculum level had no effect on the magnitude of the decrease. At 21°C, 42 d of storage resulted in a more pronounced decrease in numbers of L. monocytogenes than it did during storage at 7°C, with numbers of the pathogen decreasing by 1.7, 1.6, and 3.4 orders of magnitude for strains Scott A, V7, and California, respectively. All strains of L. monocytogenes not only survived but grew in evaporated milk stored at 7 or 21 °C for 56 or 28 d, respectively.

Role of Hydrogen Peroxide in the Prevention of Growth and Aflatoxin Production by Aspergillus parasiticus.

Hydrogen peroxide, 0.0, 0.03, 0.05, 0.3 and 0.5% was added to 25 ml of a glucose-yeast-salts medium which was inoculated with 1 ml of a spore suspension containing 106 conidia of Aspergillus parasiticus NRRL 2999 and then was incubated at 14 or 28°C. Cultures held at 28°C were analyzed after 3, 7 and 10 d for mycelial dry weight, pH and accumulation of aflatoxin B1 and G1. Incubation of some cultures at 28°C was continued for 90 d. Cultures held at 14°C were analyzed after 1, 2 and 3 months for mycelial dry weight, pH and aflatoxin production. Amounts of aflatoxin produced were determined using reversed-phase high-performance liquid chromatography (HPLC). The percentage of inhibition or stimulation by the additive was used to make comparisons between treatments and control. Overall, increasing the concentration of hydrogen peroxide to 0.3 or 0.5% completely prevented growth and aflatoxin production for up to 90 d of incubation at 14 or 28°C.

Loss of Viability by Listeria monocytogenes in Commercial Calf Rennet Extract.

Loss of viability by Listeria monocytogenes (strain California) in three lots of commercial calf rennet extract was determined during storage for 56 d at 7°C. Four levels (3 × 103 to 107/ml) of L. monocytogenes were added to the rennet extract, and McBride Listeria Agar was used to determine numbers of survivors. Selected colonies thought to be L. monocytogenes were confirmed biochemically. Samples were also tested during and after completion of cold enrichment (up to 8 weeks at 4°C). Samples of rennet extract inoculated with 103 to 104 L. monocytogenes /ml were always free of viable cells of the bacterium after 28 d and sometimes after 14 d, as determined by direct plating and cold enrichment. When the inoculum was 105 to 107/ml, samples of rennet extract usually were free of viable L. monocytogenes (direct plating and cold enrichment) after 42 d and sometimes after 28 d at 7°C. In this work, results of cold enrichment correlated well with those of direct plating. All lots of rennet extract, before inoculation, were free of L. monocytogenes (direct plating and cold enrichment).

Sodium Benzoate in the Control of Growth and Aflatoxin Production by Aspergillus parasiticus.

Sodium benzoate, 0.0, 0.1, 0.2, 0.3 or 0.4%, was added to a glucose-yeast-salts medium which was inoculated with 1 ml of a spore suspension containing 108 conidia of Aspergillus parasiticus NRRL 2999 and then was incubated at 28°C. Cultures were analyzed after 3, 7 and 10 d for mycelial dry weight, pH and accumulation of aflatoxin B1 and G1. Amounts of aflatoxin produced were determined using reversed-phase high performance liquid chromatography (HPLC). The percentage of inhibition or stimulation by the additive was used to make comparisons between treatments and control. Generally, increasing the concentration of sodium benzoate increased the percentage of inhibition at the end of incubation (10 d). However, the average accumulation of mycelial dry weight was greater in the presence of benzoate than in its absence, with the greatest increase occurring when the medium contained 0.3% sodium benzoate.

Growth and Aflatoxin Production by Aspergillus parasiticus NRRL 2999 in the Presence of Lactic Acid and at Different Initial pH values.

Twenty-five milliliters of glucose-yeast-salts medium containing 0, 0.5, 0.75, 1.0, 1.5 and 2.0% lactic acid with an initial pH of 3.5 or 4.5 were inoculated with 1 ml of a spore suspension containing 106 conidia of Aspergillus parasiticus NRRL 2999 and incubated at 28°C for 10 d. The pH of the medium, weight of mycelium and aflatoxin production were determined after 3, 7, and 10 d of incubation. Amounts of aflatoxin produced were determined using reversed-phase high-performance liquid chromatography. Cultures grown in the presence of 0.5 and 0.75% lactic acid at an initial pH of 4.5 produced more aflatoxin B1 than did the other cultures at the end of 3 d of incubation. This was not true for aflatoxin G1; with increasing concentrations of lactic acid, cultures produced decreasing amounts of aflatoxin G1. Also, cultures growing in the medium with an initial pH of 3.5 produced more aflatoxin B1 in the presence of lactic acid at the end of 3 d of incubation than did control cultures. Cultures growing in the presence of 0.5 and 0.75% lactic acid produced the most aflatoxin. Maximum amounts of aflatoxin G1 were produced after 7 d of incubation, with cultures growing in the presence of 0.5 and 0.75% lactic acid producing the most. Lactic acid did not inhibit growth (mycelium weight) of cultures in the medium with initial pH values of 3.5 or 4.5 except there was a slight decrease in mycelial weight when the medium contained 0.5% lactic acid and had an initial pH value of 3.5.

Growth and Aflatoxin Production by Aspergillus parasiticus NRRL 2999 in the Presence of Acetic or Propionic Acid and at Different Initial pH Values.

Experiments were done to determine effects of different concentrations of acetic or propionic acid in a glucose-yeast extract-salts medium with an initial pH value of 4,5 or 5.5 on growth and aflatoxin production by Aspergillus parasiticus NRRL 2999. Amounts of aflatoxin were measured with reversed-phase high-performance liquid chromatography. The maximum concentration of acetic or propionic acid that permitted growth at an initial pH of 5.5 was 1% after 7 d of incubation and 0.25% after 3 d of incubation, respectively. When the initial pH of the medium was 4.5, the maximum concentration of acetic or propionic acid that permitted growth was 0.25 or 0.1%, respectively. There was no significant difference (p>0.05) in amount of mycelial (dry weight) produced by cultures in the presence of 0.0, 0.25, 0.50 or 0.75% acetic acid. Amounts of aflatoxin B1 and G1 produced decreased with an increasing concentration of acetic acid. Increasing concentrations of propionic acid caused a decrease in the amount of mycelial dry weight and aflatoxin produced by cultures growing in the medium with an initial pH of 5.5. At an initial pH of 4.5 mycelial growth was slow and at 3 d of incubation amounts of aflatoxin B1 and G1 produced were reduced as concentrations of acetic acid increased. This also was true for propionic acid in the medium with an initial pH of 4.5. Cultures with an extended lag phase in the presence of acetic or propionic acid overcame this and then produced large amounts of aflatoxin B1 and G1 at 7 and 10 d of incubation.

Toxigenic and Nontoxigenic Strains of Aspergilli and Penicillia Grown in the Presence of Sodium Chloride Cause Enzyme-Catalyzed Hydrolysis of Protein, Fat and Hydrogen Peroxide.

Eight strains of Aspergillus flavus , three of Aspergillus parasiticus , one of Aspergillus ochraceus and ten of Penicillum spp. were evaluated for their ability to hydrolyze protein, fat and hydrogen peroxide when the molds were grown in the presence of different amounts (0-10%) of sodium chloride. Proteolytic and lipolytic activities of strains of A. flavus generally increased with an increase in the amount of sodium chloride in the medium. This was true for proteolytic and less so for lipolytic activity of A. parasiticus and A. ochraceus . Of the penicillia tested, five exhibited a marked increase and five a smaller increase in proteolytic and lipolytic activity at 2, 4 and 6% sodium chloride, but such activity either remained constant or decreased at 8 and 10% sodium chloride. Peroxidase activity in mycelia of all strains of aspergilli increased with an increase of sodium chloride in the medium. Most strains of Penicillium spp. exhibited maximum peroxidase activity at 2% sodium chloride, and some reduction in activity when the amount of sodium chloride in the medium exceeded 2%.

Growth and Aflatoxin Production by Aspergillus parasiticus in the Presence of Sodium Chloride.

Twenty-five milliliters of glucose-yeast-salt medium containing 0, 2, 4, 6, 8, or 10% NaCl was inoculated to contain, approximately 105 or 107 conidia of Aspergillus parasiticus NRRL 2999 and then incubated at 13 or 28°C. Amounts of aflatoxin produced were determined using Reversed-Phase High Performance Liquid Chromatography (HPLC). Increasing the concentration of NaCl reduced accumulation of aflatoxin and also induced a lag in growth of the culture. At 13°C, the mold produced small amounts of aflatoxin after an extended lag phase, and NaCl was markedly more inhibitory at 13 than at 28°C.

Growth of and Aflatoxin Production by Aspergillus parasiticus in a Medium Containing Potassium Chloride or a Mixture of Potassium Chloride and Sodium Chloride.

Twenty-five milliliters of glucose-yeast-salts medium containing 0, 2, 4, 6, 8 and 10% KCl or a mixture of NaCl (%) and KCl (%) (0:0, 1.5:0.5, 3.25:0.75, 4.75:1.25, 6.5:1.5, and 8:2) was inoculated with 1 ml of a spore suspension containing 106 conidia of Aspergillus parasiticus NRRL 2999 and incubated at 28°C for 10 d. The pH, dry weight of mycelium and aflatoxin production were determined after 3, 7 and 10 d of incubation. Amounts of aflatoxin produced were determined using reverse-phase high-performance liquid chromatography (HPLC). The mold growing in the presence of 0, 2 and 4% KCl produced maximum amounts of aflatoxin after 3 d, whereas in the presence of 6, 8 and 10% KCl it did so after 7 d. This trend was also true when the mold grew in the presence of mixtures of NaCl and KC1. Amounts of aflatoxin produced decreased with increasing concentrations of KCl or of the mixture of NaCl and KCl. The mycelial dry weight increased with increasing concentrations of KCl or the mixture of NaCl and KCl, although there was an extended lag phase at higher concentrations of both treatments.