Isothermal study of Congo Red dye biosorptive removal from water by Solanum tuberosum and Pisum sativum peels in economical way

Solanum tuberosum (STP) and Pisum sativum peels (PSP) were used for removal of toxic Congo Red dye using indigenous sources. Potato (Solanum tuberosum) and pea (Pisum sativum) are commonly and abundantly cultivated plants in Asian countries and their peels are easily available. The optimized conditions for Solanum tuberosum peels (STP) and Pisum sativum peels (PSP) were: adsorbent dose; 0.8 and 0.6 g, contact time; 50 and 35 min, pH; 3 and 2, agitation speed; 200 and 125 rpm and temperature; 30 oC for both STP and PSP respectively. Isothermal studies indicated that Langmuir model followed by equilibrium data more than Freundlich model. Negative value of thermodynamic parameter ∆Go shown that Cong Red removal by both adsorbents was spontaneous and exothermic in nature. The adsorption capacity (qmax) for Solanum tuberosum and Pisum sativum peels were found to be 6.9 and 16.4 mg.g-1, respectively. Higher value of qmax for pea peels shown that it is more suitable adsorbent for removal of Congo Red dye than potato peels.               KEY WORDS: Congo red, Solanum tuberosum, Pisum sativum, Biosorption Bull. Chem. Soc. Ethiop. 2018, 32(2), 213-223.DOI: https://dx.doi.org/10.4314/bcse.v32i2.

Atmospheric pressure plasma and depositions of antibacterial coatings

Healthcare-associated infections (HCAI) are complications of healthcare that result in elevated patient morbidity and mortality. HCAI present a huge financial burden for patients, hospitals and insurers due to extended hospitalisation and associated care. According to the estimations, in the US alone, HCAI affects approximately 2 million patients annually, of whom approximately 90.000 patients die, with an estimated annual cost estimated to range from 28 billion to 45 billion US$. [1] European Union is facing the similar situation, the European Centre for Disease Prevention and control (ECDC) advice that approximately 4.1 million acute care patients acquire a HCAI annually, with 37.000 deaths directly attributed to HCAI. With increasing prevalence of HCAI across European countries and threatening development of antimicrobial resistance to widely used antibiotics, there is a recognised need for novel approach in battle against this healthcare burden [2]. One of the approaches involves a development and fabrication of materials with antimicrobial properties. Usually, these are coatings with integrated antibacterial agent that is responsible for the elimination of microorganisms that come into contact with active surface. There is a variety of different antibacterial compounds integrated in such coatings, such as different antibiotics, chemical compounds, peptides. Recently, metal nanoparticles (NPs) have been increasingly used in designing coatings with antibacterial properties due to their large surface-to-volume ration, physiochemical properties and biological multi-target mechanism of actions. Besides all beneficial properties of NPs their emergence of cytotoxicity is limiting their practical applications in human body. [3-4] To overcome this drawback it is important to design a new class of antibacterial coatings with firmly embedded NPs that allows controlled release of antimicrobial agent into the microenvironment. Atmospheric pressure plasma technology has shown a big promise as an alternative and cost-efficient method for deposition of coatings with antibacterial properties. This contribution explores the potential of plasma-assisted approach for fabrication of antibacterial coatings, containing different metal NPs on medical textiles. Plasma-assisted deposition of coatings was carried out with so-called ˝sandwich technique˝, where nanoparticles were embedded between two layers in order to tailor the desirable ion release and to prolong antibacterial effect of fabrics. Antibacterial effects of different nano-coatings were tested against G+ and G- bacterial species, Staphylococcus aureus and Escherichia coli, respectively. Besides antibacterial properties, potential cytotoxic effects were also studied. The study demonstrates that atmospheric pressure plasma can be an efficient technique for deposition of antibacterial coatings containing metal NPs. Medical textiles with plasma-assisted nano-coatings showed effective antibacterial properties. The choice of proper metal antimicrobial agent and optimal concentration of NPs should be considered in regards to potential cytotoxic effects when these materials would be used in medical environments.info:eu-repo/semantics/publishedVersio

Atmospheric-pressure plasma spray deposition of silver/HMDSO nanocomposite on polyamide 6,6 with controllable antibacterial activity

"Paper presented at the ICON2019 conferences in Çorlu, Tekirdağ, Turkey April 17-19, 2019"Novel coatings containing silver nanoparticles (AgNPs) with strong bonding and controllable antibacterial activity on polyamide 6,6 fabric were produced by dielectric barrier discharge (DBD) plasmaassisted deposition at atmospheric pressure and hexamethyldisiloxane (HMDSO) layers. Silver ion release was tuned using a “sandwich” coating structure to prolong the antibacterial effect. The novel spray-assisted deposition increased deposition rates of AgNPs using atmospheric pressure DBD plasma treatment when an HMDSO layer was applied. An increase in AgNPs deposition in plasma treated samples and antimicrobial activity against Gram-negative (Escherichia coli) for samples with an additional HMDSO layer was observed. These coatings allow the development of new and safe wound dressings able to switch the antimicrobial effect against Gram- positive and Gram-negative bacteria by washing the dressing at high temperature (75 oC) before application.This work was funded by European Regional Development funds (FEDER) through the Competitiveness and Internationalization Operational Program (POCI) – COMPETE and by National Funds through Portuguese Fundação para a Ciência e Tecnologia (FCT) under the project UID/ CTM/00264/2019. Ana Ribeiro acknowledges FCT for its doctoral grant SFRH/BD/137668/2018. Andrea Zille also acknowledges fnancial support of the FCT through an Investigator FCT Research contract (IF/00071/2015) and the project PTDC/CTM-TEX/28295/2017 fnanced by FCT, FEDER, and POCI in the frame of the Portugal 2020 program

DBD plasma treatment and chitosan layers - A green method for stabilization of silver nanoparticles on polyamide 6.6

The addition of silver nanoparticles (AgNPs) to biomedical textiles can be of great interest to protect the materials against microorganisms and prevent their spread. However, the human and environmental over‐exposure to AgNPs is leading to numerous concerns due to their toxicity. In this work, AgNPs were stabilized onto polyamide 6.6 fabrics (PA66) through atmospheric dielectric barrier discharge (DBD) plasma treatment and the use of chitosan (Ch) layers applied by spray. DBD plasma treatment revealed a crucial role in AgNPs adhesion (4.8 and 6.3 At%). A first layer of Ch decreased the AgNPs adhesion in both untreated and DBD plasma‐treated samples but treated samples show higher concentration (1.7 and 4.1 At%). The antibacterial activity was evaluated against Staphylococcus aureus and Escherichia coli after 2 and 24 h, showing a superior action in all samples with DBD plasma treatment after 24 h. The Ch in the first layers of the composites delayed the antimicrobial action of the samples but it also may enhance antimicrobial action. The obtained coatings will allow the development of novel and safe wound dressings with improved AgNPs deposition, controlled ions released and consequently, manage the antimicrobial performance and minimize the AgNPs side effects

Double Dielectric Barrier (DBD) plasma-assisted deposition of chemical stabilized nanoparticles on polyamide 6,6 and polyester fabrics

The development of new multifunctional textiles containing nanoparticles (NPs) has had a special interest in several applications for pharmaceutical, medical, engineering, agricultural, and food products.[1-2] Cu, Zn and especially Ag NPs exhibit strong antibacterial activities on a broad spectrum of bacteria.[3-5] Most of the antimicrobial textiles coated with NPs are not able to perform a controlled release of the antibiotic species. Thus, the immobilization of NPs in the substrate or its inclusion in polymeric matrix is essential to control the NPs antibiotic effect with time. Dielectric barrier discharge (DBD) plasma technology is one of the most effective non-thermal plasma sources.[6] However, an even dispersion and coating of NPs onto fabrics remain a challenge due to the high degree of aggregation of metal NPs.[7] Some capping agents were described to increase the suspension stability such as citrate and SDS.[8] In this work, Ag, Zn, and Cu NPs deposition on DBD plasma pre-treated polyamide 6,6 (PA66) and polyester (PES) were tested for the production of durable antibacterial textiles. SEM-EDX analysis and the effect of some NPs stabilizers (e.g. sodium citrate, sodium alginate and Polyvinyl alcohol (PVA)) was analysed by dynamic light scattering (DLS) in term of size, polydispersity index and zeta potential. XPS analyses prove the DBD efficacy in providing oxygen species onto the fabric’s surfaces. The SEM analyses prove the deposition of the Ag and Cu NPs onto the PES and PA66 fabrics. No zinc was detected. However, antimicrobial tests in PES shows that all the NPs have an antimicrobial effect but Cu and Zn show activity only in S. aureus and Ag only in E.coli. Cu shows a reasonable dispersion onto the fibres but PVP coated AgNPs display a high level of aggregation even after 1 hour of ultrasonic treatment. To solve instability and aggregation problems, NPs suspensions were prepared in different concentrations (1, 2.5 and 5 wt%) of citrate, alginate and PVA using water and ethanol as control by ultrasonic bath. In table 1 are resumed the best results obtained for each NP compared to water as control. Ethanol and PVA were disregarded due to the highest instability and lowest ζ potential, respectively. XPS, SEM and antimicrobial data shows lack in coating uniformity. It is clear that doesn't exist a univocal dispersant and concentration for all NPs. Despite the improving in ζ potentials and stability of the colloids, the obtained sizes still show a high degree of aggregation.info:eu-repo/semantics/publishedVersio

Antimicrobial efficacy of low concentration PVP-silver nanoparticles deposited on DBD plasma-treated polyamide 6,6 fabric

In this study, a low concentration (10 μg·mL−1) of poly(N-vinylpyrrolidone) (PVP)-coated silver nanoparticles (AgNPs) were deposited by spray and exhaustion (30, 70 and 100 ◦C) methods onto untreated and dielectric barrier discharge (DBD) plasma-treated polyamide 6,6 (PA66) fabric. DBD plasma-treated samples showed higher AgNP deposition than untreated ones for all methods. After five washing cycles, only DBD plasma-treated samples displayed AgNPs on the fabric surface. The best-performing method was exhaustion at 30 ◦C, which exhibited less agglomeration and the best antibacterial efficacy against S. aureus (4 log reduction). For E. coli, the antimicrobial effect showed good results in all the exhaustion samples (5 log reduction). Considering the spray method, only the DBD plasma-treated samples showed some bacteriostatic activity for both strains, but the AgNP concentration was not enough to have a bactericidal effect. Our results suggest DBD plasma may be a low cost and chemical-free method for the preparation of antibacterial textiles, allowing for the immobilization of a very low—but effective—concentration of AgNPs.This work was funded by European Regional Development funds (FEDER) through the Competitiveness and Internationalization Operational Program (POCI) – COMPETE and by National Funds through Fundação para a Ciência e Tecnologia (FCT)—under the project POCI-01-0145-FEDER-007136 and UID/CTM/00264/2019. Isabel Ribeiro (SFRH/BD/137668/2018) acknowledges FCT, Portugal, for its doctoral grant financial support. A. Zille also acknowledges financial support of the FCT through an Investigator FCT Research contract (IF/00071/2015) and the project PTDC/CTM-TEX/28295/2017 financed by FCT, FEDER and POCI in the frame of the Portugal 2020 program

CONSIDERATIONS REGARDING PLANTS PROTECTION BY MEANS OF BIOFERTILIZERS / BIOINSECTICIDES

The paper presents some aspects regarding the utilization of certain ecological substances as an alternative to environmental-friendly insecticides, in order to obtain some ecological products within the context of the increasesd concern for ecological products

Unexpected high-energy γ emission from decaying exotic nuclei

Abstract The N = 52 Ga 83 β decay was studied at ALTO. The radioactive 83Ga beam was produced through the ISOL photofission technique and collected on a movable tape for the measurement of γ-ray emission following β decay. While β-delayed neutron emission has been measured to be 56–85% of the decay path, in this experiment an unexpected high-energy 5–9 MeV γ-ray yield of 16(4)% was observed, coming from states several MeVs above the neutron separation threshold. This result is compared with cutting-edge QRPA calculations, which show that when neutrons deeply bound in the core of the nucleus decay into protons via a Gamow–Teller transition, they give rise to a dipolar oscillation of nuclear matter in the nucleus. This leads to large electromagnetic transition probabilities which can compete with neutron emission, thus affecting the β-decay path. This process is enhanced by an excess of neutrons on the nuclear surface and may thus be a common feature for very neutron-rich isotopes, challenging the present understanding of decay properties of exotic nuclei

First Evidence of Shape Coexistence in the Ni-78 Region : Intruder 0(2)(+) State in Ge-80

The N = 48 Ge-80 nucleus is studied by means of beta-delayed electron-conversion spectroscopy at ALTO. The radioactive Ga-80 beam is produced through the isotope separation on line photofission technique and collected on a movable tape for the measurement of gamma and e(-) emission following beta decay. An electric monopole E0 transition, which points to a 639(1) keV intruder 0(2)(+) state, is observed for the first time. This new state is lower than the 2(1)(+) level in Ge-80, and provides evidence of shape coexistence close to one of the most neutron-rich doubly magic nuclei discovered so far, Ni-78. This result is compared with theoretical estimates, helping to explain the role of monopole and quadrupole forces in the weakening of the N = 50 gap at Z = 32. The evolution of intruder 0(2)(+) states towards Ni-78 is discussed.Peer reviewe