Search results for: dual antibacterial activity

Authors: Melissa Dorsey

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Moral distress and compassion fatigue plague nurses in the Cardiothoracic Intensive Care Unit (CTICU) and cause an unnecessary level of turnover. Dueling Burnout describes an initiative that was implemented in the CTICU to reduce the level of burnout the nurses endure by encouraging dual roles with collaborating departments. Purpose: Critical care nurses are plagued by burnout, moral distress, and compassion fatigue due to the intensity of care provided. The purpose of the dual role program was to decrease these issues by providing relief from the intensity of the critical care environment while maintaining full-time employment. Relevance/Significance: Burnout, moral distress, and compassion fatigue are leading causes of Cardiothoracic Critical Care (CTCU) turnover. A contributing factor to burnout is the workload related to serving as a preceptor for a constant influx of new nurses (RN). As a result of these factors, the CTICU averages 17% nursing turnover/year. The cost, unit disruption, and, most importantly, distress of the clinical nurses required an innovative approach to create an improved work environment and experience. Strategies/Implementation/Methods: In May 2018, a dual role pilot was initiated for nurses. The dual role constitutes .6 full-time equivalent hours (FTE) worked in CTICU in combination with .3 FTE worked in the Emergency Department (ED). ED nurses who expressed an interest in cross-training to CTICU were also offered the dual role opportunity. The initial hypothesis was that full-time employees would benefit from a change in clinical setting leading to increased engagement and job satisfaction. The dual role also presents an opportunity for professional development through the expansion of clinical skills in another specialty. Success of the pilot led to extending the dual role to areas beyond the ED. Evaluation/Outcomes/Results: The number of dual role clinical nurses has grown to 22. From the dual role cohort, only one has transferred out of CTICU. This is a 5% turnover rate for this group of nurses as compared to the average turnover rate of 17%. A role satisfaction survey conducted with the dual role cohort found that because of working in a dual role, 76.5% decreased their intent to leave, 100% decreased their level of burnout, and 100% reported an increase in overall job satisfaction. Nurses reported the ability to develop skills that are transferable between departments. Respondents emphasized the appreciation gained from working in multiple environments; the dual role served to transform their care. Conclusions/Implications: Dual role is an effective strategy to retain experienced nurses, decrease burnout and turnover, improve collaboration, and provide flexibility to meet staffing needs. The dual role offers RNs an expansion of skills, relief from high acuity and orientee demands, while improving job satisfaction.

Keywords: nursing retention, burnout, pandemic, strategic staffing, leadership

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Authors: Ajay Krishnamurthy, Mariyappan Mahesh Kumar, Sellamuthu Periyar Selvam

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Fruits are considered as functional foods due to the presence of various bioactive compounds available such as polyphenols, which are beneficial to health when consumed as part of our diet. The primary objective of this study was to analyze the various functional groups present in ethanolic extracts of Hylocereus undatus and Garcinia indica and also measure their antibacterial and antioxidant potential respectively thereby affirming its nutraceutical potential. To fulfill our objective, a Fourier - transform Infrared Spectroscopy (FTIR) was conducted for functional group analysis, Total Phenolic Content and DPPH free radical scavenging activity for measuring it anti-oxidant potential and agar-well diffusion assay for antibacterial potential. On careful observation and analysis of the spectrum it was found that both the fruit extracts contain similar compounds viz. Phenols, Alkanes, Alkenes, Aldehydes, Ketones, Carboxylic Acid and Amines. Total phenolic content of H.undatus and G.indica was estimated to be (26.85 ± 1.84 mg GAE/100g) and (32.84 ± 1.63 mg GAE/100g) respectively which corresponds to an inhibition of 84% and 81% respectively. H.undatus shows an inhibition of (3.4 ± 2.1mm) in gram-positive and (4.2 ± 2.24mm) in gram-negative organism on the other hand G.indica shows (2.1 ± 0.98mm) in gram-positive and (3.1 ± 1.44mm) in gram negative. The presence of such diverse compounds in the fruits helps us to understand the necessity for the inclusion of fruits in our daily diet and also helps the pharmaceutical industry in realizing the importance of exotic fruits as a potential nutraceutical.

Keywords: DPPH, fourier-transform infrared spectroscopy (FTIR), Hylocereus undatus, Garcinia indica

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Authors: Włodzimierz Przewodowski, Agnieszka Przewodowska

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Colloidal metal nanoparticles have drawn increasing attention in the field of phytopathology because of their unique properties and possibilities of applications. Their antibacterial activity, no induction of the development of pathogen resistance and the ability to penetrate most of biological barriers make them potentially useful in the fighting against dangerous pathogens. These properties are very important in the case of protection of strategic crops in the world, like potato - fourth crop in the world - which is host to numerous pathogenic microorganisms causing serious diseases, significantly affecting yield and causing the economic losses. One of the most important and difficult to reduce pathogen of potato plant is quarantine bacterium Clavibacter michiganensis ssp. sepedonicus (Cms) responsible for ring rot disease. Control and detection of these pathogens is very complicated. Application of healthy, certified seed material as well as hygiene in potato production and storage are the most efficient ways of preventing of ring rot disease. Currently used disinfectants and pesticides, have many disadvantages, such as toxicity, low efficiency, selectivity, corrosiveness, and the inability to eliminate the pathogens in potato tissue. In this situation, it becomes important to search for new formulations based on components harmful to health, yet efficient, stable during prolonged period of time and a with wide range of biocide activity. Such capabilities are offered by the latest generation of biocidal nanoparticles such as colloidal metals. Therefore the aim of the presented research was to develop newly antibacterial preparation based on colloidal metal nanoparticles and checking their influence on the Cms bacteria. Our preliminary results confirmed high efficacy of the nano-colloids in controlling the this selected pathogen.

Keywords: clavibacter michiganensis ssp. sepedonicus, colloidal metal nanoparticles, phytopathology, bacteria

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Authors: Mohammed S. Razali, Kamel Khimeche, Dahah Hichem, Ammar Boudjellal, Djamel E. Kaderi, Nourddine Ramdani

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The use of additive manufacturing technologies has revolutionized various aspects of our daily lives. In particular, 3D printing has greatly advanced biomedical applications. While fused filament fabrication (FFF) technologies have made it easy to produce or prototype various medical devices, it is crucial to minimize the risk of contamination. New materials with antibacterial properties, such as those containing compounded silver nanoparticles, have emerged on the market. In a previous study, we prepared a newly sintered seashell filler (SSh) from bio-based seashells found along the Mediterranean coast using a suitable heat treatment process. We then prepared a series of polylactic acid (PLA) and polybutylene succinate (PBS) biocomposites filled with these SSh particles using a melt mixing technique with a twin-screw extruder to use them as feedstock filaments for 3D printing. The study consisted of two parts: evaluating the antibacterial activity of newly prepared biocomposites made of PLA and PBS reinforced with a sintered seashell in the first part and experimental and modeling analysis of the non-isothermal crystallization kinetics of these biocomposites in the second part. In the first part, the bactericidal activity of the biocomposites against three different bacteria, including Gram-negative bacteria such as (E. coli and Pseudomonas aeruginosa), as well as Gram-positive bacteria such as (Staphylococcus aureus), was examined. The PLA-based biocomposite containing 20 wt.% of SSh particles exhibited an inhibition zone with radial diameters of 8mm and 6mm against E. coli and Pseudo. Au, respectively, while no bacterial activity was observed against Staphylococcus aureus. In the second part, the focus was on investigating the effect of the sintered seashell filler particles on the non-isothermal crystallization kinetics of PLA and PBS 3D-printing composite materials. The objective was to understand the impact of the filler particles on the crystallization mechanism of both PLA and PBS during the cooling process of a melt-extruded filament in (FFF) to manage the dimensional accuracy and mechanical properties of the final printed part. We conducted a non-isothermal melt crystallization kinetic study of a series of PLA-SS and PBS-SS composites using differential scanning calorimetry at various cooling rates. We analyzed the obtained kinetic data using different crystallization kinetic models such as modified Avrami, Ozawa, and Mo's methods. Dynamic mode describes the relative crystallinity as a function of temperature; it found that time half crystallinity (t1/2) of neat PLA decreased from 17 min to 7.3 min for PLA+5 SSh and the (t1/2) of virgin PBS was reduced from 3.5 min to 2.8 min for the composite containing 5wt.% of SSh. We found that the coated SS particles with stearic acid acted as nucleating agents and had a nucleation activity, as observed through polarized optical microscopy. Moreover, we evaluated the effective energy barrier of the non-isothermal crystallization process using the Iso conversional methods of Flynn-Wall-Ozawa (F-W-O) and Kissinger-Akahira-Sunose (K-A-S). The study provides significant insights into the crystallization behavior of PLA and PBS biocomposites.

Keywords: avrami model, bio-based reinforcement, dsc, gram-negative bacteria, gram-positive bacteria, isoconversional methods, non-isothermal crystallization kinetics, poly(butylene succinate), poly(lactic acid), antbactirial activity

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Authors: Nematollah Gheibi, Nader Divan Khosroshahi, Mahdi Mohammadi Ghanbarlou

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Introduction: Nowadays, the phenomenon of bacterial resistance is one of the most important challenge of the health community in the world. Propolis is most important production of bee colonies that collected from of various plants. So far, a lot of investigations carried out about its antibacterial effects. Material and methods: Thirty gram of propolis prepared as ethanolic extract and after different process of purification, 7.5 gr of its pure form were obtained. Propolis compounds identification was performed by TLC and VLC methods. The HPLC spectrum obtaining from propolis ethanolic extract was compared with some purified standard phenolic and flavonoid substances. Antibacterial effects of ethanol extract of purified propolis were evaluated on two strains of Staphylococcus aureus and Pseudomonas aeruginosa and their MIC was determined by the microdillution assay. Results: Ethanolic propolis extraction analyzed by TLC were resulted to confirm several phenolic and flavonoid compounds in this extract and some of the confirmed by HPLC technique. Minimum inhibitory concentration (MIC) for standard Staphylococcus aureus (ATCC25923) and Pseudomonas aeruginosa (ATCC27853) strains were obtained 2.5 mg/ml and 50 mg/ml respectively. Conclusion: Bee Propolis is a mix organic compound that has a lot of beneficial effects such as anti-bacterial that emphasized in this investigation. It is proposed as a rich source of natural phenolic and flavonoids compounds in designing of new biological resources for hygienic and medical applications.

Keywords: propolis, Staphylococcus aureus, Pseudomonas aeruginosa, antibacterial

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Authors: Khosrow Maleknejad, Yaser Rostami

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In this paper, semi-orthogonal B-spline scaling functions and wavelets and their dual functions are presented to approximate the solutions of integro-differential equations.The B-spline scaling functions and wavelets, their properties and the operational matrices of derivative for this function are presented to reduce the solution of integro-differential equations to the solution of algebraic equations. Here we compute B-spline scaling functions of degree 4 and their dual, then we will show that by using them we have better approximation results for the solution of integro-differential equations in comparison with less degrees of scaling functions.

Keywords: ıntegro-differential equations, quartic B-spline wavelet, operational matrices, dual functions

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Authors: Jamie A. Prowse Turner, Jamie I. D. Campbell, Valerie A. Thompson

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The objective of the current research was to use a dual-process theory framework to explain these age-related differences in reasoning. Seventy-two older (M = 80.0 years) and 72 younger (M = 24.6 years) adults were given a variety of reasoning tests (i.e., a syllogistic task, base rate task, the Cognitive Reflection Test, and a perspective manipulation), as well as independent tests of capacity (working memory, processing speed, and inhibition), thinking styles, and metacognitive ability, to account for these age-related differences. It was revealed that age-related differences were limited to problems that required Type 2 processing and were related to differences in cognitive capacity, individual difference factors, and strategy choice. Furthermore, older adults’ performance can be improved by reasoning from another’s’ perspective and cannot, at this time, be explained by metacognitive differences between young and older adults. All of these findings fit well within a dual-process theory of reasoning, which provides an integrative framework accounting for previous findings and the findings presented in the current manuscript.

Keywords: aging, dual-process theory, performance, reasoning ability

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Authors: Lina Tenjo, Ilba Rodríguez

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The role of cultural identity in bilingual programs has been barely discussed in regards to SLA. This research focuses on providing relevant information that helps in having more knowledge about the experiences that an elementary student has during the second language learning process in a bilingual program within a multicultural context. This study explores the experience of 18 students in a dual language program, in a public elementary school in Northern Virginia, USA. It examines their dual language experience and the different ways this experience contributes to the formation of their cultural identity. The findings were studied with the purpose of determining the relationship between participants and certain aspects of cultural identity in a multicultural context. The reflections that originate from the voices of children are the key source that helps us to better understand the particular needs that young learners have during their participation in a DLP.

Keywords: acculturation, bilingual education, culture, dual language program, identity, second language acquisition

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Authors: Naheed Niaz, Nimra Naeem, Bushra Uzair, Riffat Tahira

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Antibacterial activity of different traditional plants essential oils against clinical isolates of Methicillin-resistant Staphylococcus aureus (MRSA) through disk diffusion method was evaluated. All the tested essential oils, in different concentrations, inhibited growth of S. aureus to varying degrees. Cinnamon and Thyme essential oils were observed to be the “best” against test pathogen. Even at lowest concentration of these essential oils i.e. 25 µl/ml, clear zone of inhibition was recorded 9+0.085mm and 8+0.051mm respectively, and at higher concentrations there was a total reduction in growth of MRSA. The study also focused on analyzing the synergistic effects of essential oils in combination with amoxicillin. Results showed that oregano and pennyroyal mint essential oils which were not very effective alone turned out to be strong synergistic enhancers. The activity increased with increase in concentration of the essential oils. It may be concluded from present results that cinnamon and thyme essential oils could be used as potential antimicrobial source for the treatment of infections caused by Methicillin-resistant Staphylococcus aureus (MRSA).

Keywords: Staphylococcus aureus, essential oils, antibiotics, combination therapy, minimum inhibitory concentration

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Authors: Yasunori Kobori, Nobukazu Tsukiji, Nobukazu Takai, Haruo Kobayashi

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In this paper, we study a Pulse-WidthModulation (PWM) controlled Zero-Voltage-Switching (ZVS) for single-inductor dual-output (SIDO) converters. This method can meet the industry demands for high efficiency due to ZVS and small size and low cost, thanks to single-inductor per multiple voltages. We show the single inductor single-output (SISO) ZVS buck converter with its operation and simulation and then the experimental results. Next proposed ZVS-PWM controlled SIDO converters are explained in the simulation. Finally we have proposed EMI reduction method with spread spectrum.

Keywords: DC-DC switching converter, zero-oltage switching control, single-inductor dual-output converter, EMI reduction, spread spectrum

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Authors: Murat Çeşme

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For a bridge engineer to ensure a safe footing design, it is very important to estimate the maximum scour depth around the piers as accurately as possible. Many experimental studies have been performed by several investigators to obtain information about scouring mechanism. In order to examine the effect of inclination of dual bridge piers on scour depth under clear-water conditions for various uniform flow depths, an experimental research on scaled dual bridge piers has been carried over in METU Hydromechanics Lab. Dimensional and non-dimensional curves were developed and presented to show the variation of scour depth with respect to various parameters such as footing angle with the vertical, flow depth and footing dimensions. Results of the study were compared to those obtained from a similar study performed with single inclined piers to see the effect of the second pier on scour depths. Useful equations for the design engineers were developed based on multiple regression analyses to be used for predicting local scour depths around inclined piers in uniform and non-uniform sediments.

Keywords: experimental research, inclined dual bridge piers, footing safety, scour depth, clear water condition

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Authors: Mitchell Stanton

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Background: Endovascular management is well established as a mainstay treatment option for cerebral aneurysms. It is also well established that immediate post procedural imaging can be difficult to interpret due to the presence of contrast material. However, through the use of Dual-Energy computed tomography, it has become possible to differentiate contrast extravasation and intracranial haemorrhage. This case illustrates the importance of this technology following endovascular treatment of an unruptured cerebral aneurysm. Case Presentation: A 79-year-old female was found to have an unruptured large intracavernous ICA fusiform aneurysm on CT Brain Angiogram after presenting with acute ophthalmoplegia. This ophthalmoplegia was caused by mass effect from the aneurysm and subsequently the aneurysm was treated with an endovascular flow diverting stent. CT brain was performed post operatively due to a reduced level of consciousness and this showed diffuse subarachnoid hyperdensity of the left hemisphere. The use of Dual-Energy CT allowed accurate differentiation and illustrated diffuse contrast material extravasation, allowing patient to continue on dual-antiplatelets and therapeutic anticoagulation to reduce the risk of ischaemic injury post endovascular stent. Conclusion: Endovascular treatment options for management of intracranial aneurysms are constantly evolving. The use of Dual-Energy CT therefore has an integral role in accurately diagnosing any post-operative complications. Specifically, differentiating between subarachnoid haemorrhage and contrast extravasation is vital in these patients due to the significant consequences to their ongoing management in regards to continuation or cessation of antiplatelets or anticoagulation. With increasing access to this technology, its use should become standard practice in the post-operative investigation of these patients undergoing endovascular treatment.

Keywords: aneurysm, computed tomography, contrast extravasation, dual-energy CT, endovascular, subarachnoid haemorrhage

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Authors: Justin Morton, Mohammad Khavari, Abhinav Priyadarshi, Nicole Grobert, Dmitry G. Eskin, Jiawei Mi, Kriakos Porfyrakis, Paul Prentice

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Ultrasonic cavitation is used for various processes and applications. Recently, ultrasonic assisted liquid phase exfoliation has been implemented to produce two dimensional nanomaterials. Depending on parameters such as input transducer power and the operational frequency used to induce the cavitation, bubble dynamics can be controlled and optimised. Using ultra-high-speed imagining and acoustic pressure measurements, a dual-frequency systemand its effect on bubble dynamics was investigated. A high frequency transducer (1.174 MHz) showed that bubble fragments and satellite bubbles induced from a low frequency transducer (24 kHz) were able to extend their lifecycle. In addition, this combination of ultrasonic frequencies generated higher acoustic emissions (∼24%) than the sum of the individual transducers. The dual-frequency system also produced an increase in cavitation zone size of∼3 times compared to the low frequency sonotrode. Furthermore, the high frequency induced cavitation bubbleswere shown to rapidly oscillate, although remained stable and did not transiently collapse, even in the presence of a low pressure field. Finally, the spatial distribution of satellite and fragment bubbles from the sonotrode were shown to increase, extending the active cavitation zone. These observations elucidated the benefits of using a dual-frequency system for generating nanomaterials with the aid of ultrasound, in deionised water.

Keywords: dual-frequency, cavitation, bubble dynamics, graphene

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Authors: Ramin Khamedi, Isa Ahmadi

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In this study acoustic emission (AE) signals obtained during deformation and fracture of two types of ferrite-martensite dual phase steels (DPS) specimens have been analyzed in frequency domain. For this reason two low carbon steels with various amounts of carbon were chosen, and intercritically heat treated. In the introduced method, identifying the mechanisms of failure in the various phases of DPS is done. For this aim, AE monitoring has been used during tensile test of several DPS with various volume fraction of the martensite (VM) and attempted to relate the AE signals and failure mechanisms in these steels. Different signals, which referred to 2-3 micro-mechanisms of failure due to amount of carbon and also VM have been seen. By Fast Fourier Transformation (FFT) of signals in distinct locations, an excellent relationship between peak frequencies in these areas and micro-mechanisms of failure were seen. The results were verified by microscopic observations (SEM).

Keywords: acoustic emission, dual phase steels, deformation, failure, fracture

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Authors: S. Beekrum, B. Odhav, R. Lalloo, E. O. Amonsou

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Marine microalgae are rich sources of the novel and biologically active metabolites; therefore, they may be used in the food industry as natural food ingredients and functional foods. They have several biological applications related with health benefits, among others. In the past decades, food scientists have been searching for natural alternatives to replace synthetic antioxidants. The use of synthetic antioxidants has decreased due to their suspected activity as promoters of carcinogenesis, as well as consumer rejection of synthetic food additives. The aim of the study focused on screening of phytochemicals from Cymbella biomass extracts, and to examine the in vitro antioxidant and antimicrobial potential. Cymbella biomass was obtained from CSIR (South Africa), and four different solvents namely methanol, acetone, n-hexane and water were used for extraction. To take into account different antioxidant mechanisms, seven different antioxidant assays were carried out. These include free radical scavenging (DPPH assay), Trolox equivalent antioxidant capacity (TEAC assay), radical cation (ABTS assay), superoxide anion radical scavenging, reducing power, determination of total phenolic compounds and determination of total flavonoid content. The total content of phenol and flavonoid in extracts were determined as gallic acid equivalent, and as rutin equivalent, respectively. The in vitro antimicrobial effect of extracts were tested against some pathogens (Staphylococcus aureus, Listeria monocytogenes, Bacillus subtilis, Salmonella enteritidis, Escherichia coli, Pseudomonas aeruginosa and Candida albicans), using the disc diffusion assay. Qualitative analyses of phytochemicals were conducted by chemical tests to screen for the presence of tannins, flavonoids, terpenoids, phenols, steroids, saponins, glycosides and alkaloids. The present investigation revealed that all extracts showed relatively strong antibacterial activity against most of the tested bacteria. The methanolic extract of the biomass contained a significantly high phenolic content of 111.46 mg GAE/g, and the hexane extract contained 65.279 mg GAE/g. Results of the DPPH assay showed that the biomass contained strong antioxidant capacity, 79% in the methanolic extract and 85% in the hexane extract. Extracts have displayed effective reducing power and superoxide anion radical scavenging. Results of this study have highlighted potential antioxidant activity in the methanol and hexane extracts. The obtained results of the phytochemical screening showed the presence of terpenoids, flavonoids, phenols and saponins. The use of Cymbella as a natural antioxidant source and a potential source of antibacterial compounds and phytochemicals in the food industry appears promising and should be investigated further.

Keywords: antioxidants, antimicrobial, Cymbella, microalgae, phytochemicals

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Authors: Rajani Kant Rai, Jayakrishnan Athipet

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There have been several attempts to prepare polymers with antimicrobial properties by doping with various N-halamines. Hydantoins (Cyclic N-halamine) is of importance due to their stability rechargeable chloroamide function, broad-spectrum anti-microbial action and ability to prevent resistance to the organisms. Polymerizable hydantoins are synthesized by tethering vinyl moieties to 5,5,-dialkyl hydantoin sacrificing the imide hydrogen in the molecule thereby restricting the halogen capture only to the amide nitrogen that results in compromised antibacterial activity. In order to increase the activity of the antimicrobial polymer, we have developed a scheme to maximize the attachment of chlorine to the amide and the imide moieties of hydantoin. Vinyl hydantoin monomer, (Z)-5-(4-((3-methylbuta-1,3-dien-2-yl)oxy)benzylidene)imidazolidine-2,4-dione (MBBID) was synthesized and copolymerized with a commercially available monomer, methyl methacrylate, by free radical polymerization. The antimicrobial activity of hydantoin is strongly dependent on their surface area and hence their microbial activity increases when incorporated in microspheres or nanoparticles as compared to their bulk counterpart. In this regard, smooth and rough surface microsphere of the vinyl monomer (MBBID) with commercial monomer was synthesized. The oxidative chlorine content of the copolymer ranged from 1.5 to 2.45 %. Further, to demonstrate the water purification potential, the thin column was packed with smooth or rough microspheres and challenged with simulated contaminated water that exhibited 6 log kill (total kill) of the bacteria in 20 minutes of exposure with smooth (25 mg/ml) and rough microsphere (15.0 mg/ml).

Keywords: cyclic N-halamine, vinyl hydantoin monomer, rough surface microsphere, simulated contaminated water

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Authors: Leonard D. Agana, Wendell Ace Dela Cruz, Arjan C. Lingaya, Bonifacio T. Doma Jr.

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The purpose of this paper is to study the predict the fuel performance parameters, which include drivability index (DI), vapor lock index (VLI), and vapor lock potential using distillation curve and Reid vapor pressure (RVP) of dual alcohol-gasoline fuel blends. Distillation curve and Reid vapor pressure were predicted using artificial neural networks (ANN) with macroscopic properties such as boiling points, RVP, and molecular weights as the input layers. The ANN consists of 5 hidden layers and was trained using Bayesian regularization. The training mean square error (MSE) and R-value for the ANN of RVP are 91.4113 and 0.9151, respectively, while the training MSE and R-value for the distillation curve are 33.4867 and 0.9927. Fuel performance analysis of the dual alcohol–gasoline blends indicated that highly volatile gasoline blended with dual alcohols results in non-compliant fuel blends with D4814 standard. Mixtures of low-volatile gasoline and 10% methanol or 10% ethanol can still be blended with up to 10% C3 and C4 alcohols. Intermediate volatile gasoline containing 10% methanol or 10% ethanol can still be blended with C3 and C4 alcohols that have low RVPs, such as 1-propanol, 1-butanol, 2-butanol, and i-butanol. Biography: Graduate School of Chemical, Biological, and Materials Engineering and Sciences, Mapua University, Muralla St., Intramuros, Manila, 1002, Philippines

Keywords: dual alcohol-gasoline blends, distillation curve, machine learning, reid vapor pressure

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Authors: Dawit Burusie Abdi, Mamidala Jagadesh Kumar

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In this paper, using 2D TCAD simulations, the application of a dual material gate (DMG) for suppressing ambipolar conduction in a tunnel field effect transistor (TFET) is demonstrated. Using the proposed DMG concept, the ambipolar conduction can be effectively suppressed even if the drain doping is as high as that of the source doping. Achieving this symmetrical doping, without the ambipolar conduction in TFETs, gives the advantage of realizing both n-type and p-type devices with the same doping sequences. Furthermore, the output characteristics of the DMG TFET exhibit a good saturation when compared to that of the gate-drain underlap approach. This improved behavior of the DMG TFET makes it a good candidate for inverter based logic circuits.

Keywords: dual material gate, suppressing ambipolar current, symmetrically doped TFET, tunnel FETs, PNPN TFET

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Authors: M. Gowri, E. K. Girija, V. Ganesh

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Background and Significance: Among the dental infections, inflammation and infection of the root canal are common among all age groups. Currently, the management of root canal infections involves cleaning the canal with powerful irrigants followed by intracanal medicament application. Though these treatments have been in vogue for a long time, root canal failures do occur. Treatment for root canal infections is limited due to the anatomical complexity in terms of small micrometer volumes and poor penetration of drugs. Thus, infections of the root canal seem to be a challenge that demands development of new agents that can eradicate E. faecalis. Methodology: In the present study, we synthesized and screened silver-curcumin nanoparticle against E. faecalis. Morphological cell damage and antibiofilm activity of silver-curcumin nanoparticle on E. faecalis was studied using scanning electron microscopy (SEM). Biochemical evidence for membrane damage was studied using flow cytometry. Further, the antifungal activity of silver-curcumin nanoparticle was evaluated in an ex vivo dentinal tubule infection model. Results: Screening data showed that silver-curcumin nanoparticle was active against E. faecalis. silver-curcumin nanoparticle exerted time kill effect. Further, SEM images of E. faecalis showed that silver-curcumin nanoparticle caused membrane damage and inhibited biofilm formation. Biochemical evidence for membrane damage was confirmed by increased propidium iodide (PI) uptake in flow cytometry. Further, the antifungal activity of silver-curcumin nanoparticle was evaluated in an ex vivo dentinal tubule infection model, which mimics human tooth root canal infection. Confocal laser scanning microscopy studies showed eradication of E. faecalis and reduction in colony forming unit (CFU) after 24 h treatment in the infected tooth samples in this model. Further, silver-curcumin nanoparticle was found to be hemocompatible, not cytotoxic to normal mammalian NIH 3T3 cells and non-mutagenic. Conclusion: The results of this study can pave the way for developing new antibacterial agents with well deciphered mechanisms of action and can be a promising antibacterial agent or medicament against root canal infection.

Keywords: ex vivo dentine model, inhibition of biofilm formation, root canal infection, silver-curcumin nanoparticle

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Authors: Damandeep Kaur, O.P. Pandey, M.S. Reddy

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In the present research, bio-synthesisation of silica particles has been carried out successfully. For this purpose, agriculture waste rice husk (RH) has been utilized. Among several types of agriculture waste, RH is considered to be cost-effective and easily accessible. In the present investigation, a chemical approach has been followed to extract silica nanoparticles. X-Ray Diffraction (XRD) patterns indicated the amorphous nature of silica at lower temperature range. Silica and other mineral contents have been found using energy dispersive spectroscopy (EDS). Morphological and structural studies have been carried out with the use of Field Emission Scanning Electron Microscopy (FE-SEM) and Fourier Transform Infrared Transmission (FTIR) spectroscopy. Further, extracted silica from RH has been used for preparation of the glasses. The appearance of broad humps in XRD patterns confirmed the amorphous nature of prepared glasses. These glasses exhibited enhanced antibacterial effect against both Gram-positive and Gram-negative bacteria. The as-synthesized glass samples can be further used for physical and structural studies for drug loading applications.

Keywords: rice husk, biosynthesized silica, bioactive glasses, antibacterial studies

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Authors: Yu-Ching Yang, Haw-Long Lee, Win-Jin Chang

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The present work numerically analyzes the transient heat transfer in the absorber plates of a flat-plate solar collector based on the dual-phase-lag (DPL) heat conduction model. An efficient numerical scheme involving the hybrid application of the Laplace transform and control volume methods is used to solve the linear hyperbolic heat conduction equation. This work also examines the effect of different medium parameters on the behavior of heat transfer. Results show that, while the heat-flux phase lag induces thermal waves in the medium, the temperature-gradient phase lag smoothens the thermal waves by promoting non-Fourier diffusion-like conduction into the medium.

Keywords: absorber plates, dual-phase-lag, non-Fourier, solar collector

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Authors: Abdel-Mohdy, A. Abou-Okeil, S. El-Sabagh, S. M. El-Sawy

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Chitosan polyacrylic acid composite membranes were prepared by a bulk polymerization method in the presence of N, N'-methylene bisacrylamide (crosslinker) and ammonium persulphate as initiator. Membranes prepared from this copolymer in presence and absence of Ag nanoparticles were characterized by measuring mechanical and physical properties, water up-take and antibacterial properties. The results obtained indicated that the prepared membranes have antibacterial properties which increases with adding Ag nanoparticles.

Keywords: Ag nanoparticles , antimicrobial, Membrane, composites, mechanical properties, physical properties

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Authors: Rumeysa Gunduz, Dirk Koester, Thomas Schack

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Previous behavioral studies have shown that working memory (WM) and manual actions share limited capacity cognitive resources, which in turn results in execution costs of manual actions in WM. However, to the best of our knowledge, there is no study investigating the neurophysiology of execution costs. The current study aims to fill this research gap investigating the neurophysiology of execution costs of grasping in WM phases (encoding, maintenance, retrieval) considering verbal and visuospatial domains of WM. A WM-grasping dual task paradigm was implemented to examine execution costs. Baseline single task required performing verbal or visuospatial version of a WM task. Dual task required performing the WM task embedded in a high precision grasp to place task. 30 participants were tested in a 2 (single vs. dual task) x 2 (visuo-spatial vs. verbal WM) within subject design. Event related potentials (ERPs) were extracted for each WM phase separately in the single and dual tasks. Memory performance for visuospatial WM, but not for verbal WM, was significantly lower in the dual task compared to the single task. Encoding related ERPs in the single task revealed different ERPs of verbal WM and visuospatial WM at bilateral anterior sites and right posterior site. In the dual task, bilateral anterior difference disappeared due to bilaterally increased anterior negativities for visuospatial WM. Maintenance related ERPs in the dual task revealed different ERPs of verbal WM and visuospatial WM at bilateral posterior sites. There was also anterior negativity for visuospatial WM. Retrieval related ERPs in the single task revealed different ERPs of verbal WM and visuospatial WM at bilateral posterior sites. In the dual task, there was no difference between verbal WM and visuospatial WM. Behavioral and ERP findings suggest that execution of grasping shares cognitive resources only with visuospatial WM, which in turn results in domain specific execution costs. Moreover, ERP findings suggest unique patterns of costs in each WM phase, which supports the idea that each WM phase reflects a separate cognitive process. This study not only contributes to the understanding of cognitive principles of manual action control, but also contributes to the understanding of WM as an entity consisting of separate modalities and cognitive processes.

Keywords: dual task, grasping execution, neurophysiology, working memory domains, working memory phases

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Authors: Djendi Mohmaed

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In this paper, we propose a dual adaptive algorithm, which is based on the combination between the forward blind source separation (FBSS) structure and the affine projection algorithm (APA). This proposed algorithm combines the advantages of the source separation properties of the FBSS structure and the fast convergence characteristics of the APA algorithm. The proposed algorithm needs two noisy observations to provide an enhanced speech signal. This process is done in a blind manner without the need for ant priori information about the source signals. The proposed dual forward blind source separation affine projection algorithm is denoted (DFAPA) and used for the first time in an airplane cockpit context to enhance the communication from- and to- the airplane. Intensive experiments were carried out in this sense to evaluate the performance of the proposed DFAPA algorithm.

Keywords: adaptive algorithm, speech enhancement, system mismatch, SNR

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Authors: Walaa Al-Maghraby

Abstract:

Endophytes are organisms that colonize internal plant tissues without causing apparent harm to their host. Almost all groups of microorganisms have been found in endophytic association with plants may be fungi. They stimulate the production of secondary metabolites with a diverse range of biological activities. Leptadenia pyrotechnica is a more or less leafless, erect shrub with straight stems which is highly distributed in Saudi Arabia. Four endophytes fungi were isolated from Leptadenia pyrotechnica and identified using 18S ribosomal RNA sequences, which revealed four fungi genuses, namely Aspergillus terreus; Aspergillus welwitschiae; Aspergillus fumigatus and Aspergillus flavus. In this present study, four endophytic fungi from Leptadenia pyrotechnica were used for obtaining crude aqueous and ethyl acetate extracts for antimicrobial screening against 6 human pathogens, the antibacterial tests presented satisfactory results, where the pathogenic bacteria were inhibited by the four extracts tested, except for Escherichia coli that was inhibited by all extracts except ethyl acetate extract of Aspergillus terreus. Analysis of variance showed that the extract produced by endophyte Leptadenia pyrotechnica was the most effective against all bacteria, either gram-negative or positive. However, the extract was not efficient against pathogenic fungi. Therefore, this study indicates that endophytes from medicinal plant Leptadenia pyrotechnica could be potential sources of antibacterial substances.

Keywords: antimicrobial activity, Aspergillus sp, endophytes, Leptadenia pyrotechnica

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Authors: Ainur Bulasheva

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During the last decade, the dual learning system (DLS) has been actively introduced in various industries in Kazakhstan, including both vocational, post-secondary, and higher education levels. It is a relatively new practice-oriented approach to training qualified personnel in Kazakhstan, officially introduced in 2012. Dual learning was integrated from the German vocational education and training system, combining practical training with part-time work in production and training in an educational institution. The policy of DLS has increasingly focused on decreasing youth unemployment and the shortage of mid-level professionals by providing incentives for employers to involve in this system. By participating directly in the educational process, the enterprise strives to train its future personnel to meet fast-changing market demands. This study examines the effectiveness of DLS from the perspective of employers to understand the motivations of businesses to participate (invest) in this program. The human capital theory of Backer, which predicts that employers will invest in training their workers (in our case, dual students) when they expect that the return on investment will be greater than the cost - acts as a starting point. Further extensionists of this theory will be considered to understand investing intentions of businesses. By comparing perceptions of DLS employers and non-dual practices, this study determines the efficiency of promoted training approach for enterprises in the Kazakhstan agri-food industry.

Keywords: vocational and technical education, dualeducation, human capital theory, argi-food industry

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Authors: Shashi Kant Mishra

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In this paper, we consider semi-infinite mathematical programming problems with equilibrium constraints (SIMPEC). We establish necessary and sufficient optimality conditions for the SIMPEC, using convexificators. We study the Wolfe type dual problem for the SIMPEC under the ∂∗convexity assumptions. A Mond-Weir type dual problem is also formulated and studied for the SIMPEC under the ∂∗-convexity, ∂∗-pseudoconvexity and ∂∗quasiconvexity assumptions. Weak duality theorems are established to relate the SIMPEC and two dual programs in the framework of convexificators. Further, strong duality theorems are obtained under generalized standard Abadie constraint qualification (GS-ACQ).

Keywords: mathematical programming problems with equilibrium constraints, optimality conditions, semi-infinite programming, convexificators

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Authors: Mansur Abdulrasheed, Ibrahim I. Hussein, Ahmed M. Mubarak, Ahmed F. Umar

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This study was aimed at evaluating the phytochemical constituents and the antimicrobial activity of the seed oil of Moringa oleifera and garlic against some selected food-borne microorganisms (Staphylococcus aureus, Escherichia coli, Salmonella spp and Pseudomonas aeruginosa) using disc diffusion method. The results of the phytochemical screening revealed differences in the presence of the phytochemicals among the extracts. Saponins were detected in both Moringa oleifera and garlic seed oil, while alkaloid and tannins were observed in seed oil of garlic. Furthermore, the antibacterial assay results show that the seed oil of Moringa oleifera was inactive against all the tested organisms, even at 100 % concentration. In contrast, garlic oil was found to be active against all the tested organisms. The highest inhibition was observed in E. coli (12 mm) at 100 % concentration, while at 20 % concentration, Salmonella Sp and P. aeruginosa showed the least inhibiton (6 mm). The antimicrobial activity of the seed oil of garlic may be attributed to its phytochemicals components which were not detected in the seed oil of Moringa oleifera. The results of this study have shown the potentials of the seed oil of garlic as an antimicrobial agent more especially in foods, by inhibiting the growth of the test organisms, which range from food-borne pathogens to food spoilage organisms.

Keywords: antimicrobial, garlic, Moringa oleifera, food borne pathogens

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Authors: Kambiz Rasoulkhani, Jeanne Cole, Sybil Sharvelle, Ali Mostafavi

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Dual water distribution systems have been proposed as solutions to enhance the sustainability and resilience of urban water systems by improving performance and decreasing energy consumption. The objective of this study was to evaluate the long-term resilience and robustness of dual water distribution systems versus singular water distribution systems under various stressors such as demand fluctuation, aging infrastructure, and funding constraints. To this end, the long-term dynamics of these infrastructure systems was captured using a simulation model that integrates institutional agency decision-making processes with physical infrastructure degradation to evaluate the long-term transformation of water infrastructure. A set of model parameters that varies for dual and singular distribution infrastructure based on the system attributes, such as pipes length and material, energy intensity, water demand, water price, average pressure and flow rate, as well as operational expenditures, were considered and input in the simulation model. Accordingly, the model was used to simulate various scenarios of demand changes, funding levels, water price growth, and renewal strategies. The long-term resilience and robustness of each distribution infrastructure were evaluated based on various performance measures including network average condition, break frequency, network leakage, and energy use. An ecologically-based resilience approach was used to examine regime shifts and tipping points in the long-term performance of the systems under different stressors. Also, Classification and Regression Tree analysis was adopted to assess the robustness of each system under various scenarios. Using data from the City of Fort Collins, the long-term resilience and robustness of the dual and singular water distribution systems were evaluated over a 100-year analysis horizon for various scenarios. The results of the analysis enabled: (i) comparison between dual and singular water distribution systems in terms of long-term performance, resilience, and robustness; (ii) identification of renewal strategies and decision factors that enhance the long-term resiliency and robustness of dual and singular water distribution systems under different stressors.

Keywords: complex systems, dual water distribution systems, long-term resilience performance, multi-agent modeling, sustainable and resilient water systems

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Authors: S. Barbaqadze, M. Goderdzishvili, E. Mosidze, L. Lomtadze, V. Mshvildadze, L. Bakuridze, D. Berashvili, A. Bakuridze

Abstract:

This paper focuses on the formulation of phytobiotic designated for further implantation in poultry farming. Composition was meant to be water-soluble powder containing antibacterial essential oils. The development process involved Thyme, Monarda and Clary sage essential oils. The antimicrobial activity of essential oils composite was meant to be tested against gram-negative and gram-positive bacterial strains. The results are processed using the statistical program Sigma STAT. To make essential oils composition water soluble surfactants were added to them. At the first stage of the study, nine options for the optimal composition of essential oils and surfactants were developed. The effect of the amount of surfactants on the essential oils composition solubility in water has been investigated. On the basis of biopharmaceutical studies, the formulation of phytobiotic has been determined: Thyme, monarda and clary sage essential oils 2:1:1 - 100 parts; Licorice extract 5.25 parts and inhalation lactose 300 parts. A technology for the preparation of phytobiotic has been developed and a technological scheme for the preparation of phytobiotic has been made up. The research was performed within the framework of the grant project CARYS-19-363 funded be the Shota Rustaveli National Science Foundation of Georgia.

Keywords: clary, essential oils, monarda, phytobiotics, poultry, thyme

Procedia PDF Downloads 143