Green synthesis of zinc oxide nanoparticles using Amygdalus scoparia Spach stem bark extract and their applications as an alternative antimicrobial,anticancer, and anti-diabetic agent

For the first time in this study, Zinc oxide nanoparticles were biosynthesized by the eco-friendly and cost-effective procedure using Amygdalus scoparia stem bark extract then used as antibacterial, antifungal, anticancer, and anti-diabetic agents. The characterization techniques confirmed the biosynthesis, crystalline nature, structure, size, elemental composition of ZnO NPs and bioactive compounds that exist in A. scoparia extract accounting for Zn²⁺ ion reduction, capping and stabilization of ZnO NPs. The ZnO NPs displayed remarkable inhibitory activity against E. coli, E. aerigenes, S. aureus, P. oryzae, F. thapsinum, and F. semitectum compared to antibiotic standards. The ZnO NPs showed significant inhibitory effects on cancer cell lines, while it had no toxic effect on Vero normal cell line. The ZnO NPs (30 mg/kg)-treated diabetic rats showed significantly higher levels of insulin and lower AST, ALT and blood glucose compared with the STZ induced diabetic group and other treated groups (P < 0.05). The ZnO NPs- and extract-treated rats showed significantly higher levels of IR, GluT2, and GCK expression and lower TNFα expression compared with the STZ induced diabetic rats. Our findings showed that ZnO NPs represented an outstanding performance for biological applications.     

Planetary motion cross bar friction test for application in machining process

This paper describes a new method to evaluate the friction coefficient at the tool-work interface in machining process where high stress and temperature are caused. In order to examine the feasibility of the proposed method, the present report introduces the method and the results obtained only at room temperature. Ti6Al4V, SUS304, AISI1045, FCD 700, FCD 450 and FC300 were used as work materials, while TiN coated carbide tool, TiAlN coated carbide tool and P15 were used as tool materials. The proposed method provided the friction coefficients of different coatings against different work materials, and demonstrated the variability of friction coefficient and the anisotropy of surface roughness.     

Novel Gemini Cationic Surfactants: Thermodynamic,Antimicrobial Susceptibility,and Corrosion Inhibition Behavior against Acidithiobacillus ferrooxidans

The Egyptian oil and gas industry is suffering from severe metal corrosion problems, particularly microbial-induced corrosion. There is limited knowledge on the corrosion inhibition of carbon steels in the presence of an acidophilic, iron-oxidizing bacterial species Acidithiobacillus ferrooxidans. Therefore, in this study, novel Gemini cationic surfactants, in three forms depending on variation in alkyl chains of 8, 12, and 16 carbon atoms named FHPAO, FHPAD, and FHPAH, respectively, were synthesized and characterized by Fourier transform infrared and nuclear magnetic resonance spectroscopy. The surface parameters and the thermodynamic of the synthesized surfactants were evaluated at three different temperatures, 20, 40, and 60 °C. The synthesized Gemini cationic surfactants were tested as broad-spectrum antimicrobial, antibacterial and anticandida agents. They evaluated as biocides and corrosion inhibitors against Acidithiobacillus ferrooxidans. FHPAD showed higher adsorption ability at the solution interface and higher affinity to construct micelles than FHPAO and FHPAH. Both adsorption and micellization processes were hydrophobic and temperature dependent. FHPAO, FHPAD and FHPAH exhibited wide-spectrum antimicrobial activities, and the highest activity and the lowest minimum bactericidal/fungicidal inhibitory concentrations were attributed to FHPAD. Furthermore, synthesized FHPAD demonstrated the highest metal corrosion inhibition efficiency of 95.5% at 5 mM in comparison to 87.5% and 81.7% for FHPAO and FHPAH, respectively. In conclusion, this study provides novel synthesized cationic surfactants with many applications in the oil and gas industry, such as broad-spectrum antimicrobial, biocides, and corrosion inhibitors for acidophilic, iron-oxidizing bacterial species Acidithiobacillus ferrooxidans.     

Application of Cudrania tricuspidata leaf extract as a washing agent to inactivate Listeria monocytogenes on fresh-cut romaine lettuce and kale

The present study aimed to examine the antimicrobial activity of silkworm thorn (Cudrania tricuspidata) leaf extract (CTLE) and its application as a washing agent for fresh-cut romaine lettuce and kale. The antimicrobial activities of CTLE at various concentrations against Listeria monocytogenes were determined using disc diffusion and viable cell count assays, and CTLE exhibited strong inactivation of L. monocytogenes. In particular, after the treatment with 0.4% CTLE, the protein content of L. monocytogenes cells was significantly (P < 0.05) decreased from 507.21 to 254.58 μg mL⁻¹, and damaged cells were observed by scanning electron microscopy. CTLE washing resulted in approximately 2-log reduction of microbial growth, similar to that of 0.01% NaOCl. In addition, CTLE washing did not affect the quality of romaine lettuce and kale. Therefore, these results suggest that CTLE is applicable as a new washing agent for inactivating L. monocytogenes on fresh-cut romaine lettuce and kale.     

枞树型核电轮槽精铣刀制造技术优化设计

以枞树型叶根精铣刀为例,阐述了可换硬质合金型线刀体和刀片精铣刀的优化设计、制造工艺、建模及优化设计,进行切削过程加工策略优化和加工过程模拟,设计制造了锥柄专用工装及检测环规、磨削刀片后角专用工装,采用NUMROTO软件编制刀片加工工步。该项目研制的可换刀片精铣刀型线精度完全能达到进口铣刀水平,能满足大部分轮槽与叶根加工对型线精度的要求,可以大幅度节约刀具费用。     

Effect of antimicrobial packaging on physicochemical and microbial quality of chicken drumsticks

The effects of antimicrobial agents (nisin, chitosan, potassium sorbate (PS) or silver substituted zeolite (AgZeo)) incorporated into low density polyethylene (LDPE) on the physicochemical and microbial quality of chicken drumsticks stored at 5 °C for 6 days were investigated. Active multilayer bags (LDPE/polyamide/LDPE-containing 2% antimicrobial agent) were used to pack chicken drumsticks under vacuum. Their efficiency in inhibiting total aerobic mesophilic bacteria (APC), total coliforms and total molds and yeasts were evaluated by comparison with control bag (LDPE-polyamide-LDPE). APC counts of samples packed in bags containing chitosan, nisin, AgZeo and PS were 1.03, 0.98, 0.51, and 0.17 log respectively were lower than those of samples packed in control bags. Samples packaged in active bags had lower microbial counts and thiobarbituric acid reactive substance (TBARS) values than those of samples packed in control bags. The pH, color and hardness of the samples were not affected significantly by use of different packaging films (p > 0.05). Therefore, the bag including chitosan or nisin can be suggested as a suitable packaging material for chicken drumstick to increase safety and quality.     

Determination of sensory thresholds of Mentha piperita L. essential oil in selected tropical fruit juices and efficacy of sensory accepted concentrations combined with mild heat to inactivate foodborne pathogens

This study determined the compromised acceptance threshold (CAT) and rejection threshold (RT) of Mentha piperita L. essential oil (MPEO) in cajá, guava and mango juices. The MPEO concentrations below the RT values were evaluated alone or combined with mild heat treatment (MHT; 54 °C) to inactivate ≥5-log₁₀ of Escherichia coli O157:H7 and Salmonella Enteritidis PT 4 in the same juices. The CAT of MPEO varied from 0.30 to 0.32 μL mL⁻¹, while the RT was 1.34 or 1.36 μL mL⁻¹ in the tested juices. Only concentrations of MPEO close, or higher than the RT caused ≥5-log₁₀ reductions in the tested pathogens in cajá, guava and mango juices. Combined with MHT, concentrations of MPEO below the RT reduced ≥5-log₁₀ of both pathogens in juices. These findings indicate that MPEO concentrations below the RT in combination with MHT is a feasible preservation technology to ensure the safety of tropical fruit juices.     

Biocontrol of Listeria monocytogenes by lactic acid bacteria isolated from brewer's grains used as feedstuff in Argentina

Brewer's grains are the most important by-product of the brewery industry and it is mostly used as a protein and energy source in animal nutrition. Listeria monocytogenes is a food-borne pathogen can cause invasive diseases such as meningoencephalitis, sepsis, abortion, and gastroenteritis in humans and several animal species. The aim of this work was to study the antilisterial activity of lactic acid bacteria (LAB) isolated from brewer's grains. The incidence of Listeria spp. in brewer's grains was 3.12%. Twenty-one LAB inhibited the growth of the eight strains of L. monocytogenes. The mean inhibition halo of cell free supernatants of LAB ranged between 11.5 and 24.5 mm. The isolation of lactic acid bacteria with antilisterial activity from brewer's grains is promising based on their capacity to produce antimicrobial compounds. The production of antimicrobial metabolites by LAB in the substrate would generate an unfavorable environment for the growth of the pathogenic bacterium under study.     

Purification and characterization of a novel bacteriocin CAMT2 produced by Bacillus amyloliquefaciens isolated from marine fish Epinephelus areolatus

A novel bacteriocin named CAMT2 was produced by strain ZJHD3-06 which was isolated from the marine fish Epinephelus areolatus and identified as Bacillus amyloliquefaciens, Bacteriocin CAMT2 inhibits important food spoilage and food-borne pathogens such as Listeria monocytogenes, Staphylococcus aureus, Escherichia coli and Vibrio parahaemolyticus. Bacteriocin CAMT2 was purified by ammonium sulfate precipitation, gel filtration chromatography on Sephadex G-50 and reversed phase chromatography on a C₁₈ column. The molecular mass of the purified bacteriocin CAMT2 was about 20.0 kDa and N-terminal sequencing of the peptides revealed low similarity with existing antimicrobial peptides, as determined by an LC–MS/MS system. Bacteriocin CAMT2 was resistant for up to 100 °C and pH ranging 2–10, but lost its activity when treated with protease K. The bacteriocin also showed significant antimicrobial activity against L. monocytogenes in a meat model system. These obtained results suggest that bacteriocin CAMT2 has potential for use as a food biopreservative.     

Tinospora cordifolia mediated facile green synthesis of cupric oxide nanoparticles and their photocatalytic,antioxidant and antibacterial properties

The study reports a facile method for the green synthesis of copper oxide nanoparticles (CuO Nps) by a solution combustion method using Tinospora cordifolia water extract. The Nps were characterized by XRD, SEM, TEM and UV–visible studies. XRD data indicates the formation of pure monoclinic crystallite structures of CuO Nps. SEM images show that the particles have sponge like structure with large surface area and the average crystallite sizes were found to be ~6–8 nm. These observations were confirmed by TEM analysis. Photocatalytic activity studies of CuO Nps reveal that they act as very good catalyst for the effective degradation of methylene blue (MB) in the presence of UV and Sun light. Also, the degradation of MB was found to be pH dependent. The Nps found to inhibit the activity of 1,1-Diphenyl-2-picrylhydrazyl (DPPH) free radicals effectively. CuO Nps exhibit significant bactericidal activity against Klebsiella aerogenes, Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus. The study reveals a simple, ecofriendly and robust method for the synthesis of multifunctional CuO nanoparticle employing underutilized medicinal plants.