Silver Nanoparticles and Sodium Hypochlorite Inhibitory Effects on Biofilm Produced by Pseudomonas aeruginosa from Poultry Farms

In Egypt, pseudomonas infection is one of the most important problems facing poultry production. Pseudomonas spp. is recognized as a major food spoiler and environmental contaminant. Biofilm formation by P. aeruginosa has an important role in the bacterial pathogenesis as well as persistence in the environment. The antibacterial and antibiofilm activities of AgNPs and NaOCL were evaluated against P. aeruginosa isolated from chicken farms. MIC and MBC of AgNPs against planktonic cells of P. aeruginosa were 15 and 20µg/ml, respectively. While those of NaOCL were 2200 and 2600 µg/ml, respectively. The highest inhibition percentages of biofilm formation (97.9%) was observed when P. aeruginosa treated with AgNPs (25µg/ml). While, 87.5% biofilm removal percentage was achieved after treating the established biofilm with 25 µg/ml AgNPs for 2.5 h. Moreover, NaOCL (2800 µg/ml) was able to cause 96.6% inhibition of biofilm formation and 90.3% biofilm removal after 1.5 h contact. The current study revealed that AgNPs and NaOCL were able to promote a significant reduction and removal of the mature biofilms formed by P. aeruginosa and the antibiofilm efficiency increased with the increase of its contact times with the biofilms

Inhibitory Activity of Silver Nanoparticles and Sodium Hypochlorite against Biofilm Produced by Salmonellae Isolated from Poultry Farms

Salmonella typhimurium and Salmonella enteritidis are among the predominant Salmonella serotypes in the Egyptian poultry farms. Salmonella has the ability to build up biofilms on a variety of surfaces. The antibiofilm activities of silver nanoparticles (AgNPs) and sodium hypochlorite (NaOCL) on prevention and controlling of biofilm by Salmonella spp. was estimated. Silver nanoparticles exhibited bactericidal activity against both S. typhimurium and S. enteritidis with MIC value at 15 µg/ml, while, that of NaOCL was 1600 µg/ml. AgNPs (25 ug/ml) could inhibit biofilm formation at percentages of 84.96% and 78.85% against S. typhimurium and S. enteritidis, respectively. A percentage of 87 % biofilm removal by AgNPS after 3 h contact with the built-up biofilm produced by S. typhimurium and S. enteritidis was recorded. NaOCL (2200 µg/ml) exhibited inhibition percentages of biofilm formation at 83.89% and 75.76% against S. typhimurium and S. enteritidis, respectively. While, biofilm removal percentages after 2 h contact between NaOCL (2200 µg/ml) with the formed biofilm by S. typhimurium and S. enteritidis were 87.42% and 89.37%, respectively. It can be concluded that AgNPs and NaOCl were able to promote a significant reduction of biofilm formation by S. typhimurium and S. enteritidis. Also, AgNPs and NaOCl effectively oppress the mature biofilms formed and the antibiofilm efficiency increased with the increase of contact time with the biofilms

Development of Metal Matrix Composites and Related Forming Techniques by Direct Recycling of Light Metals: A Review

In this contribution, researchers have provided a summary of the agricultural and industrial waste recoveries to be deployed as the composite reinforced materials. It covers the work of previous researchers related to this area and addressed the key challenge to overcome for further development and advancement. The major contributions of this work were a comprehensive review on a wide variety of Sever Plastic Deformation (SPD) techniques implementation in development of the waste materials based reinforced metal matrix composite. The waste materials can be derived from either industrial or natural sources. Also, it discusses the range of Metal Matrix Composites (MMCs) applications in engineering and related manufacturing techniques with further emphasized on the process parameters which directly determine the material properties. Some useful suggestions were proposed to the industrialists, academicians and scientists to further improve the performance aspect of Metal Matrix Composites (MMCs) for commercialization reason. Furthermore, industrial and natural waste enhancement materials have been strongly proposed because of their higher reinforced content particulates such as alumina (Al2O3) and silica (SiO2). Also, the mechanical and physical properties are directly influenced by the size, shape and weight-volume friction of the composites as same as the potential reactions between matrixes/reinforced materials interfac

Indoor air concentration from selective laser sintering 3d printer using Virgin Polyamide Nylon (PA12) Powder: a pilot study

Environmental emissions from additive manufacturing (AM) have attracted much attention recently. The capability in fabricating complex part make AM famous in developing prototype and product in various industries, especially in aerospace, medical, automotive, and manufacturing industries. However, the study on emission and exposure mainly focusses on the desktop type such as fused deposition modelling. This study investigates the emission and indoor concentration from powder bed fusion of selective laser sintering (SLS) technologies. Prior to the investigation, virgin PA12 has undergone characterization in terms of morphology, size and thermal analysis. Calibration block using virgin polyamide nylon (PA12) is selected to be printed in this study. Parameters such particulate matter size 2.5 μm (PM 2.5), total volatile organic compound (TVOC), carbon dioxide (CO2), formaldehyde, temperature and relative humidity (RH) are set to be monitored through real-time sampling of 8 hours based on Industry Code of Practice on Indoor Air Quality 2010 by Department Occupational Safety and Health (DOSH) Malaysia. Four phases of the printing process involve are background data, preprinting, during printing and post-printing. Based on the study it was found that PM 2.5 and CO2 exceed the acceptable limit recommended by DOSH Malaysia during the preparation of powder (preprinting) at 1218 ppm and 1070 μg/m3 respectively. Meanwhile TVOC concentration was influenced by the sintered powder temperature and recorded at 0.5 ppm. Temperature, relative humidity and formaldehyde were maintained throughout the SLS process. Mitigation strategies using mechanical ventilation and personal protective equipment (PPE) are recommended to be used to reduce the potential of occupational hazard to the operators

Two-dimensional infrared correlation spectroscopy, conductor-like screening model for real solvents, and density functional theory study on the adsorption mechanism of polyvinylpolypyrrolidone for effective phenol removal in an aqueous medium

The discharge of industrial effluents, such as phenol, into aquatic and soil environments is a global problem due to its serious negative impacts on human health and aquatic ecosystems. In this study, the ability of polyvinylpolypyrrolidone (PVPP) to remove phenol from an aqueous medium was investigated. The results showed that a significant proportion of phenol (up to 74.91%) was removed using PVPP at pH 6.5. Isotherm adsorption experiments of phenol on PVPP indicated that the best-fit adsorption was obtained using Langmuir models. The response peaks of the hydroxyl groups of phenol (OH) and the carboxyl groups (i.e., C=O) of PVPP were altered, indicating the formation of a hydrogen bond between the PVPP and phenol during phenol removal, as characterized using 1D and 2D IR spectroscopy. The resulting complexes were successfully characterized based on their thermodynamic properties, Mulliken charge, and electronic transition using the DFT approach. To clarify the types of interactions taking place in the complex systems, quantum theory of atoms in molecules (QTAIM) analysis, reduced density gradient noncovalent interaction (RDG-NCI) approach, and conductor-like screening model for real solvents (COSMO-RS) approach were also successfully calculated. The results showed that the interactions that occurred in the process of removing phenol by PVPP were through hydrogen bonding (based on RDG-NCI and COSMO-RS), which was identified as an intermediate type (∇2ρ(r) > 0 and H < 0, QTAIM). To gain a deeper understanding of how these interactions occurred, further characterization was performed based on adsorption mechanisms using molecular electrostatic potential, global reactivity, and local reactivity descriptors. The results showed that during hydrogen bond formation, PVPP acts as a nucleophile, whereas phenol acts as an electrophile and the O9 atom (i.e., donor electron) reacts with the H22 atom (i.e., acceptor electron)

ELECTROMYOGRAPHY ANALYSIS ASSOCIATED WITH PROLONGED STANDING IN METAL STAMPING INDUSTRY

Many jobs in metal stamping industry require workers to perform in standing position. Standing is a practical working position when the workers are lifting heavy products, and pushing or pulling excessive loads because those jobs require a stable position and large degree of freedom. However, if the workers perform the jobs continuously in standing throughout the working hours, they may be experience muscle fatigue. The objective of this study such as to measure the myoelectric levels (μV) exerted by the left and right erector spinae, left and right tibialis anterior. The myoelectric levels in the muscles were measured using surface Electromyography (sEMG). Ten production workers from a metal stamping industry participated as subjects for sEMG measurement. Out of which, five workers from metal stamping process lines and another five from handwork section. The muscle activity of the subjects was measured for 5 hours and 45 minutes of continuous standing during beginning of workday, middle of workday, and end of workday from Monday to Wednesday. Results of comparison found that the two groups of workers show significant difference (p-value &lt; 0.05) in myoelectric level in the right erector spinae, right gastrocnemius, and left tibialis anterior during the beginning of workday. However, the two groups of workers did not show any significant difference in myoelectric level during the middle of the workday and end of the workday. It can be concluded that muscle activity of the workers was determined by the work load and duration of standing. This study suggests that anti fatigue mat and micro breaks should be provided to the workers to reduce muscle fatigue

The Suaineadh Project : a stepping stone towards the deployment of large flexible structures in space

The Suaineadh project aims at testing the controlled deployment and stabilization of space web. The deployment system is based on a simple yet ingenious control of the centrifugal force that will pull each of the four daughters sections apart. The four daughters are attached onto the four corners of a square web, and will be released from their initial stowed configuration attached to a central hub. Enclosed in the central hub is a specifically designed spinning reaction wheel that controls the rotational speed with a closed loop control fed by measurements from an onboard inertial measurement sensor. Five other such sensors located within the web and central hub provide information on the surface curvature of the web, and progression of the deployment. Suaineadh is currently at an advanced stage of development: all the components are manufactured with the subsystems integrated and are presently awaiting full integration and testing. This paper will present the current status of the Suaineadh project and the results of the most recent set of tests. In particular, the paper will cover the overall mechanical design of the system, the electrical and sensor assemblies, the communication and power systems and the spinning wheel with its control system

The influence of graphitization catalyst electrode in electrical discharge machining of polycrystalline diamond-finishing condition

Electrical Discharge Machining (EDM) is a non-contact machining process that becomes famous in machining of Polycrystalline Diamond (PCD). The material is typically used as the cutting tools for aerospace and automotive industries. However, low electrical conductivity and high melting temperature of PCD has caused slower EDM process. This investigation purposely designed to investigate the influence of different types of electrode which are Copper (ordinary electrode) and Copper-Nickel (newly proposed graphitization catalyst electrode) on EDM performance of MRR and Ra. Interestingly the newly proposed electrode gave positive impact to the investigated performance indication. Cu-Ni electrode recorded 35% better in MRR than the Cu electrode, though with higher short-circuiting rate. Cu-Ni also provided the lowest Ra value with 10% better than the best Ra produced by Cu electrode. This phenomenon occurred as due to the high interaction between the catalyst materials of nickel and diamond which supported by the qualification data provided in this investigation

Upregulation of brain renin angiotensin system by 27-hydroxycholesterol in Alzheimer's disease

In spite of the fact that cholesterol does not pass the blood-brain barrier, hypercholesterolemia has been linked to increase Alzheimer's disease (AD) risk. Hypertension is another risk factor and angiotensin converting enzyme (ACE) activity is known to be increased in AD. Furthermore, a lower incidence of AD has been reported in patients taking anti-hypertensive drugs. Here we show that the levels of angiotensinogen (AGT) and ACE are increased in the cerebrospinal fluid (CSF) of patients with mild cognitive impairment and AD. Moreover, we show ACE activity in the CSF to be positively correlated with both plasma and CSF levels of 27-hydroxycholesterol (27-OH), an oxysterol known to pass through the BBB and taken up from the circulation by the brain. In addition, treatment of rat primary neurons, astrocytes, and human neuroblastoma cells with 27-OH resulted in increased production of AGT. Our results demonstrate that upregulation of renin-angiotensin system (RAS) in AD brains occurs not only at the enzymatic level (ACE) but also at the substrate level (AGT). The possibility that 27-OH is part of a mechanism linking hypercholesterolemia with increased brain RAS activity and increased AD risk is discussed