Search results for: multidrug resistance of pathogens

Authors: S. Zouari, H. Ghorbel, H. Liao, R. Elleuch

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Research is increasingly moving towards the use of surface treatment processes to limit environmental effects. Electrolytic plating has traditionally been seen as a way to protect brass products, especially faucets, from mechanical and chemical damage. However, this method was not effective industrially, economically and ecologically. The aim of this work is to develop non-usual polymer coatings for brass faucets in order to improve the performance of brass and to replace electrolytic chromium coatings, thereby reducing environmental impact. Fluorinated-Ethylene-Propylene polymer (FEP) was chosen for its excellent mechanical and chemical properties and its good environmental performance. This coating was developed by spraying (painting) process onto brass substrates. The coatings obtained were characterized using a scanning electron microscope to evaluate the morphology of the deposits and their porosity rate. Grid adhesion, surface energy and corrosion tests (salt spray) were also performed to evaluate the mechanical and chemical behavior of these coatings properly. The results show that the deposits obtained have a homogeneous microstructure with a very low porosity rate. The results of the grid adhesion test prove the conformity of the test according to the NF077 standard. The coatings have a hydrophobic character following the low values of surface energy obtained and a very good resistance to corrosion. These results are interesting and may represent real technological issues in the industrial field.

Keywords: FEP coatings, spraying process, brass, adhesion, surface energy, corrosion resistance

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Authors: Zhu Xinxin, Wang Hui, Yang Kai

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Heat flux is one of the most important test parameters in the ground thermal protection test. Slug calorimeter is selected as the main sensor measuring heat flux in arc wind tunnel test due to the convenience and low cost. However, because of excessive lateral heat transfer and the disadvantage of the calculation method, the heat flux measurement error of the slug calorimeter is large. In order to enhance measurement accuracy, the heat insulation structure and heat flux calculation method of slug calorimeter were improved. The heat transfer model of the slug calorimeter was built according to the energy conservation principle. Based on the heat transfer model, the insulating sleeve of the hollow structure was designed, which helped to greatly decrease lateral heat transfer. And the slug with insulating sleeve of hollow structure was encapsulated using a package shell. The improved insulation structure reduced heat loss and ensured that the heat transfer characteristics were almost the same when calibrated and tested. The heat flux calibration test was carried out in arc lamp system for heat flux sensor calibration, and the results show that test accuracy and precision of slug calorimeter are improved greatly. In the meantime, the simulation model of the slug calorimeter was built. The heat flux values in different temperature rise time periods were calculated by the simulation model. The results show that extracting the data of the temperature rise rate as soon as possible can result in a smaller heat flux calculation error. Then the different thermal contact resistance affecting calculation error was analyzed by the simulation model. The contact resistance between the slug and the insulating sleeve was identified as the main influencing factor. The direct comparison calibration correction method was proposed based on only heat flux calibration. The numerical calculation correction method was proposed based on the heat flux calibration and simulation model of slug calorimeter after the simulation model was solved by solving the contact resistance between the slug and the insulating sleeve. The simulation and test results show that two methods can greatly reduce the heat flux measurement error. Finally, the improved slug calorimeter was tested in the arc wind tunnel. And test results show that the repeatability accuracy of improved slug calorimeter is less than 3%. The deviation of measurement value from different slug calorimeters is less than 3% in the same fluid field. The deviation of measurement value between slug calorimeter and Gordon Gage is less than 4% in the same fluid field.

Keywords: correction method, heat flux calculation, heat insulation structure, heat transfer model, slug calorimeter

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Authors: Nasrin Hosseinzad, Ramin Ghasemi Shayan

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Chemotherapy is the most common procedure in the treatment of advanced cancers but is justsoberlyoperativeand toxic. Nevertheless, the efficiency of chemotherapy is restrictedowing to multiple drug resistance(MDR). Lately, plentiful preclinical experiments have revealedthatPaclitaxel-Curcumin could be an ultimateapproach to converse MDR and synergistically increase their efficiency. The connotationsamongst B-cell-lymphoma2(BCL-2) and multi-drug-resistance-associated-P-glycoprotein(MDR1) consequence of patients forecast the efficiency of paclitaxel-built chemoradiotherapy. There are evidences of the efficacy of paclitaxel in the treatment of surface-transmission of bladder-cell-carcinoma by manipulating bio-adhesive microspheres accomplishedthroughout measured release of drug at urine epithelium. In Genetically-Modified method, muco-adhesive oily constructionoftricaprylin, Tween 80, and paclitaxel group showed slighter toxicity than control in therapeutic dose. Postoperative chemotherapy-Paclitaxel might be more advantageous for survival than adjuvant chemo-radio-therapy, and coulddiminish postoperative complications in cervical cancer patients underwent a radical hysterectomy.HA-Se-PTX(Hyaluronic acid, Selenium, Paclitaxel) nanoparticles could observablyconstrain the proliferation, transmission, and invasion of metastatic cells and apoptosis. Furthermore, they exhibitedvast in vivo anti-tumor effect. Additionally, HA-Se-PTX displayedminor toxicity on mice-chef-organs. Briefly, HA-Se-PTX mightprogress into a respectednano-scale agentinrespiratory cancers. To sum up, Paclitaxel is considered a profitable anti-cancer drug in the treatment and anti-progress symptoms in malignant cancers.

Keywords: cancer, paclitaxel, chemotherapy, tumor

Procedia PDF Downloads 134

Authors: Vinod Nair, C. Sadasivan

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Beta-lactam antibiotics are the most frequently prescribed medications in modern medicine. The antibiotic resistance by the production of enzyme beta-lactamase is an important mechanism seen in microorganisms. Resistance to beta-lactams mediated by beta-lactamases can be overcome successfully with the use of beta-lactamase inhibitors. New generations of the antibiotics contain mostly synthetic compounds, and many side effects have been reported for them. Combinations of beta-lactam and beta-lactamase inhibitors have become one of the most successful antimicrobial strategies in the current scenario of bacterial infections. Plant-based drugs are very cheap and having lesser adverse effect than synthetic compounds. The synergistic effect of eugenol acetate with beta-lactams restores the activity of beta-lactams, allowing their continued clinical use. It is reported here the enhanced inhibitory effect of phytochemical, eugenol acetate, isolated from the plant Syzygium aromaticum with beta-lactams on beta-lactamase. The compound was found to have synergistic effect with the antibiotic amoxicillin against antibiotic-resistant strain of S.aureus. The enzyme was purified from the organism and incubated with the compound. The assay showed that the compound could inhibit the enzymatic activity of beta-lactamase. Modeling and molecular docking studies indicated that the compound can fit into the active site of beta-lactamase and can mask the important residue for hydrolysis of beta-lactams. The synergistic effects of eugenol acetate with beta-lactam antibiotics may justify, the use of these plant compounds for the preparation of β-lactamase inhibitors against β-lactam resistant S.aureus.

Keywords: betalactamase, eugenol acetate, synergistic effect, molecular modeling

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Authors: Mustafa Metin Donma, Orkide Donma

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Childhood obesity is an important clinical problem because it may lead to chronic diseases during the adulthood period of the individual. Obesity is a metabolic disease associated with low-grade inflammation. The liver occurs at the center of metabolic pathways. Adropin, fibroblast growth factor-21 (FGF-21), and fetuin-A are hepatokines. Due to the immense participation of the liver in glucose metabolism, these liver-derived factors may be associated with insulin resistance (IR), which is a phenomenon discussed within the scope of obesity problems. The aim of this study is to determine the concentrations of adropin, FGF-21, and fetuin-A in childhood obesity, to point out possible differences between the obesity groups, and to investigate possible associations among these three hepatokines in obese and morbidly obese children. A total of one hundred and thirty-two children were included in the study. Two obese groups were constituted. The groups were matched in terms of mean ± SD values of ages. Body mass index values of obese and morbidly obese groups were 25.0 ± 3.5 kg/m² and 29.8 ± 5.7 kg/m², respectively. Anthropometric measurements including waist circumference, hip circumference, head circumference, and neck circumference were recorded. Informed consent forms were taken from the parents of the participants. The ethics committee of the institution approved the study protocol. Blood samples were obtained after overnight fasting. Routine biochemical tests, including glucose- and lipid-related parameters, were performed. Concentrations of the hepatokines (adropin, FGF-21, fetuin A) were determined by enzyme-linked immunosorbent assay. Insulin resistance indices such as homeostasis model assessment for IR (HOMA-IR), alanine transaminase-to aspartate transaminase ratio (ALT/AST), diagnostic obesity notation model assessment laboratory index, diagnostic obesity notation model assessment metabolic syndrome index as well as obesity indices such as diagnostic obesity notation model assessment-II index, and fat mass index were calculated using the previously derived formulas. Statistical evaluation of the study data as well as findings of the study was performed by SPSS for Windows. Statistical difference was accepted significant when p is smaller than 0.05. Statistically significant differences were found for insulin, triglyceride, high-density lipoprotein cholesterol levels of the groups. A significant increase was observed for FGF-21 concentrations in the morbidly obese group. Higher adropin and fetuin-A concentrations were observed in the same group in comparison with the values detected in the obese group (p > 0.05). There was no statistically significant difference between the ALT/AST values of the groups. In all of the remaining IR and obesity indices, significantly increased values were calculated for morbidly obese children. Significant correlations were detected between HOMA-IR and each of the hepatokines. The highest one was the association with fetuin-A (r=0.373, p=0.001). In conclusion, increased levels observed in adropin, FGF-21, and fetuin-A have shown that these hepatokines possess increasing potential going from obese to morbid obese state. Out of the correlations found with the IR index, the most affected hepatokine was fetuin-A, the parameter possibly used as the indicator of the advanced obesity stage.

Keywords: adropin, fetuin A, fibroblast growth factor-21, insulin resistance, pediatric obesity

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Authors: O. Berriche, R. Ben Othmen, H. Sfar, H. Abdesslam, S. Bou Meftah, S. Bhouri, F. Mahjoub, C. Amrouche, H. Jamoussi

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Introduction: Although current evidence emphasizes a high prevalence of vitamin D deficiency and an inverse association between serum 25-hydroxyvitamin D (25-OHD) concentration and obesity, no studies have been conducted in Tunisian obese. The objectives of our study were to estimate the vitamin D deficiency in obese, identify risk factors for vitamin D deficiency, demonstrating a possible association between vitamin D levels and metabolic parameters. Methods: This was a descriptive study of 100 obese 18-65 year-old. Anthropometric measurements were determined. Fasting blood samples were assessed for the following essays : serum calcium, 25 OH vitamin D, inorganic phosphorus, fasting glucose, HDL, LDL cholesterol and triglyceride. Insulin resistance was evaluated by fasting insulin, HOMA-IR and HOMA-ß. Consumption of foods riche in vitamin D, sunscreen use, wearing protective clothes and exposed surface were assessed through applied questionnaires. Results: The deficit of vitamin D (< 30 ng/ml) among obese was 98,8%. Half of them had a rate < 10ng/ml. Environmental factors involved in vitamin D deficiency are : the veil (p = 0,001), wearing protective clothes (p = 0,04) and the exposed surface (p = 0,011) and dietary factors are represented by the daily caloric intake (p = 0,0001). The percent of fat mass was negatively related to vitamin D levels (p = 0,01) but not with BMI (p = 0,11) or waist circumference (p = 0,88). Similarly, lipid and glucose profile had no link with vitamin D. We found no relationship between Insulin resistance and vitamin D levels. Conclusion: At the end of our study, we have identified a very important vitamin D deficiency among obese. Dosage and systematic supplementation should be applied and for that physician awareness is needed.

Keywords: insulinresistance, risk factors, obesity, vitamin D

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Authors: Iñaki Iturria, Pasquale Russo, Montserrat Nacher-Vázquez, Giuseppe Spano, Paloma López, Miguel Angel Pardo

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Introduction: It is known that some Lactic Acid Bacteria (LAB) present an interesting probiotic effect. Probiotic bacteria stimulate host resistance to microbial pathogens and thereby aid in immune response, and modulate the host's immune responses to antigens with a potential to down-regulate hypersensitivity reactions. Therefore, probiotic therapy is valuable against intestinal infections and may be beneficial in the treatment of Inflammatory Bowel Disease (IBD). Several in vitro tests are available to evaluate the probiotic potential of a LAB strain. However, an in vivo model is required to understand the interaction between the host immune system and the bacteria. During the last few years, zebrafish (Danio rerio) has gained interest as a promising vertebrate model in this field. This organism has been extensively used to study the interaction between the host and the microbiota, as well as the host immune response under several microbial infections. In this work, we report on the use of the zebrafish model to investigate in vivo the colonizing ability and the immunomodulatory effect of probiotic LAB. Methods: Lactobacillus strains belonging to different LAB species were fluorescently tagged and used to colonize germ-free zebrafish larvae gastrointestinal tract (GIT). Some of the strains had a well-documented probiotic effect (L. acidophilus LA5); while others presented an exopolysaccharide (EPS) producing phenotype, thus allowing evaluating the influence of EPS in the colonization and immunomodulatory effect. Bacteria colonization was monitored for 72 h by direct observation in real time using fluorescent microscopy. CFU count per larva was also evaluated at different times. The immunomodulatory effect was assessed analysing the differential expression of several innate immune system genes (MyD88, NF-κB, Tlr4, Il1β and Il10) by qRT- PCR. The anti-inflammatory effect was evaluated using a chemical enterocolitis zebrafish model. The protective effect against a pathogen was also studied. To that end, a challenge test was developed using a fluorescently tagged pathogen (Vibrio anguillarum-GFP+). The progression of the infection was monitored up to 3 days using a fluorescent stereomicroscope. Mortality rates and CFU counts were also registered. Results and conclusions: Larvae exposed to EPS-producing bacteria showed a higher fluorescence and CFU count than those colonized with no-EPS phenotype LAB. In the same way, qRT-PCR results revealed an immunomodulatory effect on the host after the administration of the strains with probiotic activity. A downregulation of proinflammatory cytoquines as well as other cellular mediators of inflammation was observed. The anti-inflammatory effect was found to be particularly marked following exposure to LA% strain, as well as EPS producing strains. Furthermore, the challenge test revealed a protective effect of probiotic administration. As a matter of fact, larvae fed with probiotics showed a decrease in the mortality rate ranging from 20 to 35%. Discussion: In this work, we developed a promising model, based on the use of gnotobiotic zebrafish coupled with a bacterial fluorescent tagging in order to evaluate the probiotic potential of different LAB strains. We have successfully used this system to monitor in real time the colonization and persistence of exogenous LAB within the gut of zebrafish larvae, to evaluate their immunomodulatory effect and for in vivo competition assays. This approach could bring further insights into the complex microbial-host interactions at intestinal level.

Keywords: gnotobiotic, immune system, lactic acid bacteria, probiotics, zebrafish

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Authors: Ankita Pathak, Ashok Munjal, Ravi Parkash

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Plastic responses to multiple environmental stressors in wet or dry seasonal populations of tropical Drosophila species have received less attention. We tested plastic effects of heat hardening, acclimation to drought or starvation; and changes in trehalose, proline and body lipids in D. ananassae flies reared under wet or dry season specific conditions. Wet season flies revealed significant increase in heat knockdown, starvation resistance and body lipids after heat hardening. However, accumulation of proline was observed only after desiccation acclimation of dry season flies while wet season flies elicited no proline but trehalose only. Therefore, drought-induced proline can be a marker metabolite for dry season flies. Further, partial utilization of proline and trehalose under heat hardening reflects their possible thermoprotective effects. Heat hardening elicited cross-protection to starvation stress. Stressor-specific accumulation or utilization, as well as rates of metabolic change for each energy metabolite, were significantly higher in wet season flies than dry season flies. Energy metabolite changes due to inter-related stressors (heat vs. desiccation or starvation) resulted in possible maintenance of energetic homeostasis in wet or dry season flies. Thus, low or high humidity induced plastic changes in energy metabolites can provide cross-protection to seasonally varying climatic stressors.

Keywords: wet-dry seasons, plastic changes, stress related traits, energy metabolites, cross protection

Procedia PDF Downloads 171

Authors: Vijay Samuel, Tina Thekkekkara, Shoma Ganguly

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There is no reported Hanta Seoul virus infection in children in the UK so far, making it quite challenging for clinicians in diagnosing, predicting and prognosticating the outcome of the infection to patients and parents. We report a case of a ten-year-old girl who presented with pyrexia associated with headache, photophobia and abdominal pain. The family had recently acquired two pet rats six weeks ago. She appeared flushed with peri-oral pallor, coated the strawberry tongue, inflamed tonsils and bilateral cervical lymphadenopathy. Her liver and splenic edges were palpable. Investigations showed that she was thrombocytopenic with deranged renal and liver functions. An ultrasound abdomen demonstrated a mildly enlarged spleen, peripancreatic lymph node and an acalculous cholecystitis. In view of her clinical presentation, a diagnosis of leptospirosis was considered and she was commenced on intravenous benzylpenicillin. The following day she became oliguric, developed significant proteinuria and her renal function deteriorated. Following conservative management, her urine output gradually improved along with her renal function, proteinuria and thrombocytopaenia. Serology for leptospirosis and various other viruses were negative. Following discussion with the Rare and Imported Pathogens Laboratory at Porton hanta virus serology was requested and found to be strongly positive for Seoul hanta virus. Following discharge she developed palpitations, fatigue, severe headache and cognitive difficulties including memory loss and difficulties in spelling, reading and mathematics. Extensive investigations including ECG, MRI brain and CSF studies were performed and revealed no significant abnormalities. Since 2012, there have been six cases of acute kidney injury due to Hantavirus infection in the UK. Two cases were from the Humber region and were exposure to wild rats and the other four were exposed to specially bred pet fancy rats. Hanta virus infections can cause mild flu like symptoms but two clinical syndromes are associated with severe disease including haemorrhagic fever with renal syndrome, which may be associated with thrombocytopenia and Hantavirus cardiopulmonary syndrome. Neuropsychological impairments reported following hantavirus pulmonary syndrome and following Puumala virus infection have been reported. Minor white matter lesions were found in about half of the patients investigated with MRI brain. Seoul virus has a global distribution owing to the dispersal of its carrier host rats, through global trade. Several ports in the region could explain the possible establishment of Seoul virus in local populations of rats in the Yorkshire and Humber region. The risk of infection for occupationally exposed groups is 1-3% compared to 32.9% for specialist pet rat owners. The report highlight’s the importance of routinely asking about pets in the family. We hope to raise awareness of the emergence of hantavirus infection in the UK, particularly in the Yorkshire and Humber region. Clinicians should consider hantavirus infection as a potential cause of febrile illness causing renal impairment in children. Awareness of the possible neuro-cognitive sequele would help the clinicians offer appropriate information and support to children and their families. Contacting Rare and Imported Pathogens Laboratory at Porton is a useful resource for clinicians in UK when they consider unusual infections.

Keywords: Seoul hantavirus in child Porton, UK Acute kidney injury

Procedia PDF Downloads 295

Authors: Maneesha Pahlani, Najmin Sultana

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A hospital is one of the most suitable places for acquiring an infection because it harbors a high population of virulent strains of microorganisms that may be resistant to antibiotics, especially the prevalence of Methicillin-Resistant Staphylococcus Aureus (MRSA) infections. The hospital-acquired infection has become a global challenge. In developed countries, healthcare-associated infections occur in 5-15% of hospitalized clients, affecting 9-37% of those admitted to intensive care units (ICU). A non-experimental descriptive study was conducted among 50 nursing officers working in a selected hospital in Bangalore to assess the nursing officers’ level of knowledge regarding the prevention and management of MRSA infections and to associate the pre-test knowledge mean scores of nursing officers with selected socio-demographic variables. Data was collected using a structured questionnaire consisting of socio-demographic data and a structured questionnaire on knowledge regarding the prevention and management of MRSA infections. The data was analyzed in terms of frequencies and percentages for the analysis of demographic variables and computing chi-square to determine the association between knowledge means scores and selected demographic variables. The study findings revealed that the nursing officer had an overall good level of knowledge (63.05%) regarding the prevention and management of MRSA infections, and there is no significant association found between the level of knowledge mean scores for prevention and management of MRSA infection with the selected socio-demographic variables. However, the categorization of knowledge items showed that the nursing officer must thoroughly receive education on correct guidance and information regarding MRSA infection control policy, including measures and practices on hygiene precautions and information regarding antibiotic resistance for effective nursing care to patients with MRSA infections. The conclusions drawn from the study findings showed that it is necessary that the nursing officer thoroughly receive education on correct guidance and information regarding MRSA infection control policy, including measures and practices on hygiene precautions and information regarding antibiotic resistance to provide effective nursing care to patients with MRSA infection as they constantly care for the patient who can be at risk for multi-drug resistance organisms to reduce the risk of MRSA infection in hospital care settings as well community settings.

Keywords: MRSA, nursing officers, knowledge, preventive and management

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Authors: Varsha Baweja

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Steinernema glaseri is known to be the most potent biocontrol agent against a number of insect pests of various orders and of diverse habitats under laboratory conditions. But in nature many micro pathogens may affect the efficacy of such entomopathogenic nematodes. Keeping this in view, the interaction of Steinernema glaseri with a predatory fungus Arthrobotrys superba was assessed on eight different nutrient media. The activity of A.superba was evaluated in terms of trap formation, conidiophore formation, and number of adhesive cells formed in the presence and absence of nematodes. The fungus failed to form any trap on any of the culture media in the absence of nematodes. However, in the presence of nematodes, the trap formation by the test fungus was increased but the number of conidiophores decreased with increase in dilution of Corn Meal Agar from 5% to 2%. Higher number of chlamydospores were observed in phenylalanine treated medium which indicates the inhibiting effect of phenylalanine on the growth of A. superba. Our results suggest that care should be taken during release of entomopathogenic nematodes in an agroecosystem for managing various insect pests in a more efficient manner.

Keywords: Entomopathogenic Nematode , Steinernema Glaseri, Predatory Fungus, Arthrobotrys Superba

Procedia PDF Downloads 279

Authors: Najmin Sultana, Maneesha Pahlani

Abstract:

A hospital is one of the most suitable places for acquiring an infection because it harbors a high population of virulent strains of microorganisms that may be resistant to antibiotics, especially the prevalence of Methicillin-Resistant Staphylococcus Aureus (MRSA) infections. The hospital-acquired infection has become a global challenge. In developed countries, healthcare-associated infections occur in 5-15% of hospitalized clients, affecting 9-37% of those admitted to intensive care units (ICU). A non-experimental descriptive study was conducted among 50 nursing officers working in a selected hospital in bengaluru to assess the nursing officers’ level of knowledge regarding the prevention and management of MRSA infections and to associate the pre-test knowledge mean scores of nursing officers with selected socio-demographic variables. Data was collected using a structured questionnaire consisting of socio-demographic data and a structured questionnaire on knowledge regarding the prevention and management of MRSA infections. The data was analyzed in terms of frequencies and percentages for the analysis of demographic variables and computing chi-square to determine the association between knowledge means scores and selected demographic variables. The study findings revealed that the nursing officer had an overall good level of knowledge (63.05%) regarding the prevention and management of MRSA infections, and there is no significant association found between the level of knowledge mean scores for prevention and management of MRSA infection with the selected socio-demographic variables. However, the categorization of knowledge items showed that the nursing officer must thoroughly receive education on correct guidance and information regarding MRSA infection control policy, including measures and practices on hygiene precautions and information regarding antibiotic resistance for effective nursing care to patients with MRSA infections. The conclusions drawn from the study findings showed that it is necessary that the nursing officer thoroughly receive education on correct guidance and information regarding MRSA infection control policy, including measures and practices on hygiene precautions and information regarding antibiotic resistance to provide effective nursing care to patients with MRSA infection as they constantly care for the patient who can be at risk for multi-drug resistance organisms to reduce the risk of MRSA infection in hospital care settings as well community settings.

Keywords: MRSA, knowledge, nursing officers', prevention and management

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Authors: Deepika Biswas

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Acinetobacter baumannii, a hospital-acquired pathogen, causes nosocomial infections including pneumonia, urinary tract infection, and secondary meningitis. Carbapenem is most effective antibiotics against it. Its increased resistance to carbapenems has been a rising global concern. Antibiotics such as carbapenem are unable to use on hospital setups to eradicate A. baumannii, hence different concentrations of disinfectants including phenol; sodium hypochlorite and ethanol are increasingly being used. The objective of the present study is to find an effective concentration of above disinfectants against carbapenem-resistant strain RS307 of A. baumannii. Growth kinetics of RS307 has been determined using UV-Vis spectrophotometer in the presence and absence of disinfectants in triplicate and its standard deviation has also been calculated which make the results more reliable. Differential growth curves were plotted, which showed the effective concentration among all the concentrations of phenol, sodium hypochlorite and ethanol. On disc diffusion assay, antimicrobial effect was observed by comparing all the concentrations of disinfectants to check its synergy with imipenem, most effective carbapenem. All the results collectively revealed that 0.5% phenol, 0.5% sodium hypochlorite, and 70% ethanol could preferably be used as disinfectant for hospital setup against the carbapenem-resistant strain of A. baumannii. SDS PAGE analysis showed differential expression in the protein profile of A. baumannii after treatment. The present study highlighted that few disinfectants even in low concentration had shown better antimicrobial activity hence may be recommended for regular use in the hospitals, which will be cost effective and less harmful.

Keywords: Acenatobacter bomunii, phenol, sodium hypoclirite, ethanol, carbapenem resistance, disinfectant

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Authors: Gopalu Karunakaran, Matheswaran Jagathambal, Nguyen Van Minh, Evgeny Kolesnikov, Denis Kuznetsov

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This work investigated the use of Beijerinckia indica extracellular extract for the synthesis of silver nanoparticles using AgNO₃. The formation of nanoparticles was confirmed by different methods, such as UV-Vis absorption spectroscopy, XRD, FTIR, EDX, and TEM analysis. The formation of silver nanoparticles (AgNPs) was confirmed by the change in color from light yellow to dark brown. The absorbance peak obtained at 430 nm confirmed the presence of silver nanoparticles. The XRD analysis showed the cubic crystalline phase of the synthesized nanoparticles. FTIR revealed the presence of groups that acts as stabilizing and reducing agents for silver nanoparticles formation. The synthesized silver nanoparticles were generally found to be spherical in shape with size ranging from 5 to 20 nm, as evident by TEM analysis. These nanoparticles were found to inhibit pathogenic bacterial strains. This work proved that the bacterial extract is a potential eco-friendly candidate for the synthesis of silver nanoparticles with promising antibacterial and antioxidant properties. 

Keywords: antioxidant activity, antimicrobial activity, Beijerinckia indica, characterisation, extracellular extracts, silver nanoparticles

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Authors: Mohammad M. Khan, Pankaj Agarwal

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The present investigation deals with the microstructures, mechanical and detailed wear characteristics of in situ TiC particles reinforced zinc aluminum-based metal matrix composites. The composites have been synthesized by liquid metallurgy route using vortex technique. The composite was found to be harder than the matrix alloy due to high hardness of the dispersoid particles therein. The former was also lower in ultimate tensile strength and ductility as compared to the matrix alloy. This could be explained to be due to the use of coarser size dispersoid and larger interparticle spacing. Reasonably uniform distribution of the dispersoid phase in the alloy matrix and good interfacial bonding between the dispersoid and matrix was observed. The composite exhibited predominantly brittle mode of fracture with microcracking in the dispersoid phase indicating effective easy transfer of load from matrix to the dispersoid particles. To study the wear behavior of the samples three different types of tests were performed namely: (i) sliding wear tests using a pin on disc machine under dry condition, (ii) high stress (two-body) abrasive wear tests using different combinations of abrasive media and specimen surfaces under the conditions of varying abrasive size, traversal distance and load, and (iii) low-stress (three-body) abrasion tests using a rubber wheel abrasion tester at various loads and traversal distances using different abrasive media. In sliding wear test, significantly lower wear rates were observed in the case of base alloy over that of the composites. This has been attributed to the poor room temperature strength as a result of increased microcracking tendency of the composite over the matrix alloy. Wear surfaces of the composite revealed the presence of fragmented dispersoid particles and microcracking whereas the wear surface of matrix alloy was observed to be smooth with shallow grooves. During high-stress abrasion, the presence of the reinforcement offered increased resistance to the destructive action of the abrasive particles. Microcracking tendency was also enhanced because of the reinforcement in the matrix. The negative effect of the microcracking tendency was predominant by the abrasion resistance of the dispersoid. As a result, the composite attained improved wear resistance than the matrix alloy. The wear rate increased with load and abrasive size due to a larger depth of cut made by the abrasive medium. The wear surfaces revealed fine grooves, and damaged reinforcement particles while subsurface regions revealed limited plastic deformation and microcracking and fracturing of the dispersoid phase. During low-stress abrasion, the composite experienced significantly less wear rate than the matrix alloy irrespective of the test conditions. This could be explained to be due to wear resistance offered by the hard dispersoid phase thereby protecting the softer matrix against the destructive action of the abrasive medium. Abraded surfaces of the composite showed protrusion of dispersoid phase. The subsurface regions of the composites exhibited decohesion of the dispersoid phase along with its microcracking and limited plastic deformation in the vicinity of the abraded surfaces.

Keywords: abrasive wear, liquid metallurgy, metal martix composite, SEM

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Authors: Kinga Wieczorek, Elzbieta Kukier, Remigiusz Pomykala, Beata Lachtara, Renata Szewczyk, Krzysztof Kwiatek, Jacek Osek

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The MICRORISK project (Research cooperation in assessment of microbiological hazard and risk in the food chain) was funded by the European Commission under the FP7 PEOPLE 2012 IRSES call within the International Research Staff Exchange Scheme of Marie Curie Action and realized during years from 2014 to 2015. The main aim of the project was to establish a cooperation between the European Union (EU) and the third State in the area important from the public health point of view. The following organizations have been engaged in the activity: National Veterinary Research Institute (NVRI) in Pulawy, Poland (coordinator), French Agency for Food, Environmental and Occupational Health & Safety (ANSES) in Maisons Alfort, France, National Scientific Center Institute of Experimental and Clinical Veterinary Medicine (NSC IECVM), Kharkov and State Scientific and Research Institute of Laboratory Diagnostics and Veterinary and Sanitary Expertise (SSRILDVSE) Kijev Ukraine. The results of the project showed that Ukraine used microbiological criteria in accordance with Commission Regulation (EC) No 2073/2005 of 15 November 2005 on microbiological criteria for foodstuffs. Compliance concerns both the criteria applicable at the stage of food safety (retail trade), as well as evaluation criteria and process hygiene in food production. In this case, the Ukrainian legislation also provides application of the criteria that do not have counterparts in the food law of the European Union, and are based on the provisions of Ukrainian law. Partial coherence of the Ukrainian and EU legal requirements in terms of microbiological criteria for food and feed concerns microbiological parameters such as total plate count, coliforms, coagulase-positive Staphylococcus spp., including S. aureus. Analysis of laboratory methods used for microbiological hazards control in food production chain has shown that most methods used in the EU are well-known by Ukrainian partners, and many of them are routinely applied as the only standards in the laboratory practice or simultaneously used with Ukrainian methods. The area without any legislation, where the EU regulation and analytical methods should be implemented is the area of Shiga toxin producing E. coli, including E. coli O157 and staphylococcal enterotoxin detection. During the project, the analysis of the existing Ukrainian and EU data concerning the prevalence of the most important food-borne pathogens on different stages of food production chain was performed. Particularly, prevalence of Salmonella spp., Campylobacter spp., L. monocytogenes as well as clostridia was examined. The analysis showed that poultry meat still appears to be the most important food-borne source of Campylobacter and Salmonella in the UE. On the other hand, L. monocytogenes were seldom detected above the legal safety limit (100 cfu/g) among the EU countries. Moreover, the analysis revealed the lack of comprehensive data regarding the prevalence of the most important food-borne pathogens in Ukraine. The results of the MICRORISK project are networking activities among researches originations participating in the tasks will help with a better recognition of each other regarding very important, from the public health point of view areas such as microbiological hazards in the food production chain and finally will help to improve food quality and safety for consumers.

Keywords: cooperation, European Union, food chain safety, food law, microbiological risk, Microrisk, Poland, Ukraine

Procedia PDF Downloads 377

Authors: Mishari Khajah, Mohd. Elmuntasir Ahmed, Abdullah Al-Matouq, Farah Al-Ajeel, Fatemah Dashti, Ahmed Shishter

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The overall aim of this study was to monitor and evaluate the effluent quality of a reverse osmosis (RO) reject wastewater from the biggest wastewater treatment plant in the world that is using RO and ultrafiltration membranes in their processes to reclaim water for indirect potable water reuse from municipal wastewaters. The RO reject wastewater or brine included various contaminants that could harm the human health and the environment such as trace organics, organic matters, heavy metals, nutrients and pathogens. Unfortunately, there are no legally binding regulatory guidelines for brine management in Kuwait as many countries around the world. This study monitors and evaluate the RO reject wastewater (brine) generated from the Sulaibiya Wastewater Treatment Plant. Samples were collected and analyzed about 37 parameters for one-year period, twice a month, and compare it to Kuwait Environment Public Authority, KEPA. Results showed that the heavy metals parameters were above KEPA standards, which needs to be treated.

Keywords: domestic wastewater, management, potable water, RO reject wastewater, Sulaibiya wastewater treatment plant

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Authors: Arpan Bera, Rini Ganguly, Raja Chakraborty, Amlan J. Pal

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To deal with the increasing demands for the high-density non-volatile memory devices, we need nano-sites with efficient and stable charge storage capabilities. We prepared nanocrystals (NCs) of inorganic perovskite, CsPbCl₃ coated with Cs₄PbCl₆, by colloidal synthesis. Due to the type-I band alignment at the junction, this core-shell composite is expected to behave as a charge trapping site. Using Scanning Tunneling Spectroscopy (STS), we investigated voltage-controlled resistive switching in this heterostructure by tracking the change in its current-voltage (I-V) characteristics. By applying voltage pulse of appropriate magnitude on the NCs through this non-invasive method, different resistive states of this system were systematically accessed. For suitable pulse-magnitude, the response jumped to a branch with enhanced current indicating a high-resistance state (HRS) to low-resistance state (LRS) switching in the core-shell NCs. We could reverse this process by using a pulse of opposite polarity. These two distinct resistive states can be considered as two logic states, 0 and 1, which are accessible by varying voltage magnitude and polarity. STS being a local probe in space enabled us to capture this switching at individual NC site. Hence, we claim a bright prospect of these core-shell NCs made of inorganic halide perovskites in future high density memory application.

Keywords: Core-shell perovskite, CsPbCl₃-Cs₄PbCl₆, resistive switching, Scanning Tunneling Spectroscopy

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Authors: Sharmili Routray, Kishor Chandra Biswal

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The use of corrosion resistant fiber reinforced polymer (FRP) reinforcement is beneficial in structures particularly those exposed to deicing salts, and/or located in highly corrosive environment. Generally Glass, Carbon and Aramid fibers are used for the strengthening purpose of the structures. Due to the necessities of low weight and high strength materials, it is required to find out the suitable substitute with low cost. Recent developments in fiber production technology allow the strengthening of structures using Basalt fiber which is made from basalt rock. Basalt fiber has good range of thermal performance, high tensile strength, resistance to acids, good electro‐magnetic properties, inert nature, resistance to corrosion, radiation and UV light, vibration and impact loading. This investigation focuses on the effect of fibre content and fiber orientation of basalt fibre on mechanical properties of the fabricated composites. Specimen prepared with unidirectional Basalt fabric as reinforcing materials and epoxy resin as a matrix in polymer composite. In this investigation different fiber orientation are taken and the fabrication is done by hand lay-up process. The variation of the properties with the increasing number of plies of fiber in the composites is also studied. Specimens are subjected to tensile strength test and the failure of the composite is examined with the help of INSTRON universal testing Machine (SATEC) of 600 kN capacities. The average tensile strength and modulus of elasticity of BFRP plates are determined from the test Program.

Keywords: BFRP, fabrication, Fiber Reinforced Polymer (FRP), strengthening

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Authors: Mahmoud Mabrok, Channarong Rodkhum

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Flavobacterium columanre is one of the devastating pathogen that causes noticeable economic losses in freshwater cultured fish. Like other filamentous bacteria, F. columanre tends to aggregate and fluctuate to all kind of media, thus revealing obstacles in recognition of its colonies. Since the molecular typing is the only fundamental tool for rapid and precise detection of this pathgen. The present study developed a species-specific PCR assay based on cslA unique gene of F. columnare. The cslA gene sequences of 13 F. columnare, strains retrieved from gene bank database, were aligned to identify a conserved homologous segment prior to primers design. The new primers yielded amplicons of 287 bp from F. columnare strains but not from relevant or other pathogens, unlike to other published set that showed no specificity and cross-reactivity with F. indicum. The primers were sensitive and detected as few as 7 CFUs of bacteria and 3 pg of gDNA template. The sensitivity was reduced ten times when using tissue samples. These primers precisely defined all field isolates in a double-blind study, proposing their applicable use for field detection.

Keywords: Columnaris infection, cslA gene, Flavobacterium columnare, PCR

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Authors: I. N. Nwafia, U. C. Ozumba, M. E. Ohanu, S. O. Ebede

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Antibiotic resistance is increasing globally and has become a major health challenge. Extended-spectrum beta-lactamase is clinically important because the ESBL gene are mostly plasmid encoded and these plasmids frequently carry genes encoding resistance to other classes of antimicrobials thereby limiting antibiotic options in the treatment of infections caused by these organisms. The specific objectives of this study were to determine the prevalence of ESBLs production in Escherichia coli, to determine the antibiotic susceptibility pattern of ESBLs producing Escherichia coli, to detect TEM, SHV and CTX-M genes and the risk factors to acquisition of ESBL producing Escherichia coli. The protocol of the study was approved by Health Research and Ethics committee of the University of Nigeria Teaching Hospital (UNTH), Enugu. It was a descriptive cross-sectional study that involved all hospitalized patients in UNTH from whose specimens Escherichia coli was isolated during the period of the study. The samples analysed were urine, wound swabs, blood and cerebrospinal fluid. These samples were cultured in 5% sheep Blood agar and MacConkey agar (Oxoid Laboratories, Cambridge UK) and incubated at 35-370C for 24 hours. Escherichia coli was identified with standard biochemical tests and confirmed using API 20E auxanogram (bioMerieux, Marcy 1'Etoile, France). The antibiotic susceptibility testing was done by disc diffusion method and interpreted according to the Clinical and Laboratory Standard Institute guideline. ESBL production was confirmed using ESBL Epsilometer test strips (Liofilchem srl, Italy). The ESBL bla genes were detected with polymerase chain reaction, after extraction of DNA with plasmid mini-prep kit (Jena Bioscience, Jena, Germany). Data analysis was with appropriate descriptive and inferential statistics. One hundred and six isolates (53.00%) out of the 200 were from urine, followed by isolates from different swabs specimens 53(26.50%) and the least number of the isolates 4(2.00) were from blood (P value = 0.096). Seventy (35.00%) out of the 200 isolates, were confirmed positive for ESBL production. Forty-two (60.00%) of the isolates were from female patients while 28(40.00%) were from male patients (P value = 0.13). Sixty-eight (97.14%) of the isolates were susceptible to imipenem while all of the isolates were resistant to ampicillin, chloramphenicol and tetracycline. From the 70 positive isolates the ESBL genes detected with polymerase chain reaction were blaCTX-M (n=26; 37.14%), blaTEM (n=7; 10.00%), blaSHV (n=2; 2.86%), blaCTX-M/TEM (n=7; 10.0%), blaCTX-M/SHV (n=14; 20.0%) and blaCTX-M/TEM/SHV (n=10; 14.29%). There was no gene detected in 4(5.71%) of the isolates. The most associated risk factors to infections caused by ESBL producing Escherichia coli was previous antibiotics use for the past 3 months followed by admission in the intensive care unit, recent surgery, and urinary catheterization. In conclusion, ESBLs was detected in 4 of every 10 Escherichia coli with the predominant gene detected being CTX-M. This knowledge will enable appropriate measures towards improvement of patient health care, antibiotic stewardship, research and infection control in the hospital.

Keywords: antimicrobial, Escherichia coli, extended spectrum beta lactamase, resistance

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Authors: Seyed Davar Siadat, Samira Tarashi, Abolfazl Fateh, Arfa Moshiri

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Background: The global health issue of tuberculosis (TB) still affects patients in every country. TB control may not be as effective as it should be, especially when resistant strains are involved. In this regard, mycobacterial MTases play a major role in tuberculosis, but the mechanisms underlying their function have yet to be fully deciphered. Methods: Five resistant isolates of M.tb were accumulated. As a reference strain, M.tb H37Rv (ATCC 27249) was used. For this analysis, seven putative mycobacterial MTase genes (Rv0645c, Rv1694, Rv2966c, Rv3919c, Rv2756c, Rv1988, and Rv3263), as well as Rv1392 as SAM synthase, were selected. Comparing mutations and expression levels of MTases in different strains was accomplished by PCR-sequencing and qRT-PCR. The relative expression levels of these genes were calculated using the 2 -ΔΔCt method. Results: The Rv3919c gene (T to G in codon 341) and Rv1392 gene (G to A in codon 97) were the only mutations found in the INHR strain. In all sensitive and resistant isolates, Rv0645c, Rv3263, Rv2756c, and Rv2966c were overexpressed. However, the expression of Rv1988 and Rv3919c decreased in the sensitive strains, whereas the expression of Rv1694 increased. There was also a decreased expression of Rv1392 in the INHR isolate. Conclusion: The presence of mycobacterial MTases as well as resistance to antibiotics were found to be correlated in M.tb strains. Undoubtedly, there are some MTases that are associated with the virulence process. It is necessary to conduct additional studies to fully explore the impact of mycobacterial MTases within specific strains of M.tb to develop novel diagnostic and treatment strategies.

Keywords: mycobacterium tuberculosis, drug resistance, methyltransferases, s-adenosylmethionine

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Authors: Shahid-ul-Islam, Faqeer Mohammad

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The present study was conducted to investigate the effect of annatto, teak and flame of the forest natural dyes on color, fastness, and antimicrobial property of protein based textile substrate. The color strength (K/S) of wool samples at various concentrations of dyes were analysed using a Reflective Spectrophotometer. The antimicrobial activity of natural dyes before and after application on wool was tested against common human pathogens Escherichia coli, Staphylococcus aureus, and Candida albicans, by using micro-broth dilution method, disc diffusion assay and growth curve studies. The structural morphology of natural protein fibre (wool) was investigated by Scanning Electron Microscopy (SEM). Annatto and teak natural dyes proved very effective in inhibiting the microbial growth in solution phase and after application on wool and resulted in a broad beautiful spectrum of colors with exceptional fastness properties. The results encourage the search and exploitation of new plant species as source of dyes to replace toxic synthetic antimicrobial agents currently used in textile industry.

Keywords: annatto, antimicrobial agents, natural dyes, green textiles

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Authors: Suprit Pradhan, Tshering Yangzom

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Even with availability of the modern day online insulation diagnostic technologies like partial discharge monitoring, the measurements like Dissipation Factor (tanδ), DC High Voltage Insulation Currents, Polarization Index (PI) and Insulation Resistance Measurements are still widely used as a diagnostic tools to assess the condition of stator insulation in hydro power plants. To evaluate the condition of stator winding insulation in one of the generators that have been operated since 1999, diagnostic tests were performed on the stator bars of 15 MVA generators of Basochhu Hydropower Plant. This paper presents diagnostic study done on the data gathered from the measurements which were performed in 2015 and 2016 as part of regular maintenance as since its commissioning no proper aging data were maintained. Measurement results of Dissipation Factor, DC High Potential tests and Polarization Index are discussed with regard to their effectiveness in assessing the ageing condition of the stator insulation. After a brief review of the theoretical background, the strengths of each diagnostic method in detecting symptoms of insulation deterioration are identified. The interesting results observed from Basochhu Hydropower Plant is taken into consideration to conclude that Polarization Index and DC High Voltage Insulation current measurements are best suited for the detection of humidity and contamination problems and Dissipation Factor measurement is a robust indicator of long-term ageing caused by oxidative degradation.

Keywords: dissipation Factor (tanδ), polarization Index (PI), DC High Voltage Insulation Current, insulation resistance (IR), Tan Delta Tip-Up, dielectric absorption ratio

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Authors: Ahmad Qabaha

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This paper teases out the ways in which the constructs of placelessness and mobility are articulated in modern exilic Palestinian literature and American expatriate writing. The mode of placelessness embodied by the characters of each of my two authors (expatriation in Paris Montparnasse for Hemingway's characters and involuntary exile in Europe for Jabra's) will be elicited from the orientations of their mobility. This paper argues that the proclivity of Hemingway's characters for centrifugal motion (moving away from the centre) is a strategy to increase their sense of freedom that space (expatriation), rather than place, secures. By contrast, the movement of Jabra's characters is centripetal (moving or tending to move towards the centre). It echoes his Palestinian characters' recurrent futile attempts to return to Palestine, and it expresses their resistance to the lures of exile. This paper asserts that the involuntarily exiled character (the Palestinian in this case) is a figure obsessed with and ache for a place, roots and 'a dwelling' from which he was uprooted - a place that defines his authentic existence and frames his understanding of the world in Martin Heidegger's, Simone Weil's and Gaston Bachelard's senses. In parallel, this paper explains that the expatriate character (the American in this case) views place as confining, restrictive and disagreeable, while mobility as a figure of freedom, resistance, wealth, self-fashioning and understanding/inhabiting the world. Place in this sense is associated with past, tradition, ideology, existence and being. Mobility is equivalent with modernity, progression, innovation, self-fashioning and freedom.

Keywords: American expatriate literature, exilic Palestinian literature, mobility, place, placelessness

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Authors: D. Pradhan, G. Tripathy, S. Pradhan

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Objectives: Imperviousness gainst estrogen treatments is a noteworthy reason for infection backslide and mortality in estrogen receptor alpha (ERα)- positive breast diseases. Tamoxifen or estrogen withdrawal builds the reliance of breast malignancy cells on INT3 flagging. Here, we researched the commitment of Quercetin and INT3 motioning in endocrine-safe breast tumor cells. Methods: We utilized two models of endocrine treatments safe (ETR) breast tumor: Tamoxifen-safe (TamR) and long haul estrogen-denied (LTED) MCF7 cells. We assessed the transitory and intrusive limit of these cells by Transwell cells. Articulation of epithelial to mesenchymal move (EMT) controllers and in addition INT3 receptors and targets were assessed by constant PCR and western smudge investigation. Besides, we tried in-vitro hostile to Quercetin monoclonal Antibodies (mAbs) and Gamma Secretase Inhibitors (GSIs) as potential EMT inversion remedial specialists. At last, we created stable Quercetin overexpressing MCF7 cells and assessed their EMT components and reaction to Tamoxifen. Results: We found that ETR cells procured an Epithelial to Mesenchymal move (EMT) phenotype and showed expanded levels of Quercetin and INT3 targets. Interestingly, we distinguished more elevated amount of INT3 however lower levels of INT1 and INT3 proposing a change to motioning through distinctive INT3 receptors after obtaining of resistance. Against Quercetin monoclonal antibodies and the GSI PF03084014 were powerful in obstructing the Quercetin/INT3 pivot and in part repressing the EMT process. As a consequence of this, cell relocation and attack were weakened and the immature microorganism like populace was essentially decreased. Hereditary hushing of Quercetin and INT3 prompted proportionate impacts. At long last, stable overexpression of Quercetin was adequate to make MCF7 lethargic to Tamoxifen by INT3 initiation. Conclusions: ETR cells express abnormal amounts of Quercetin and INT3, whose actuation eventually drives intrusive conduct. Hostile to Quercetin mAbs and GSI PF03084014 lessen articulation of EMT particles decreasing cell obtrusiveness. Quercetin overexpression instigates Tamoxifen resistance connected to obtaining of EMT phenotype. Our discovering propose that focusing on Quercetin and INT3 warrants further clinical Correlation as substantial restorative methodologies in endocrine-safe breast.

Keywords: endocrine, epithelial, mesenchymal, INT3, quercetin, MCF7

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Authors: Vanja Vlajkov, Ivana PajčIn, Mila Grahovac, Marta Loc, Dragana Budakov, Jovana Grahovac

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The rhizosphere soil refers to the plant roots' dynamic environment characterized by their inhabitants' high biological activity. Rhizospheric bacteria are recognized as effective biocontrol agents and considered cardinal in alternative strategies for securing ecological plant diseases management. The need to suppress fungal pathogens is an urgent task, not only because of the direct economic losses caused by infection but also due to their ability to produce mycotoxins with harmful effects on human health. Aspergillus and Fusarium species are well-known producers of toxigenic metabolites with a high capacity to colonize crops and enter the food chain. The bacteria belonging to the Bacillus genus has been conceded as a plant beneficial species in agricultural practice and identified as plant growth-promoting rhizobacteria (PGPR). Besides incontestable potential, the full commercialization of microbial biopesticides is in the preliminary phase. Thus, there is a constant need for estimating the suitability of novel strains to be used as a central point of viable bioprocess leading to market-ready product development. In the present study, 76 potential producing strains were isolated from the rhizosphere soil, sampled from different localities in the Autonomous Province of Vojvodina, Republic of Serbia. The selective isolation process of strains started by resuspending 1 g of soil samples in 9 ml of saline and incubating at 28° C for 15 minutes at 150 rpm. After homogenization, thermal treatment at 100° C for 7 minutes was performed. Dilution series (10-1-10-3) were prepared, and 500 µl of each was inoculated on nutrient agar plates and incubated at 28° C for 48 h. The pure cultures of morphologically different strains indicating belonging to the Bacillus genus were obtained by the spread-plate technique. The cultivation of the isolated strains was carried out in an Erlenmeyer flask for 96 h, at 28 °C, 170 rpm. The antagonistic activity screening included two phytopathogenic fungi as test microorganisms: Aspergillus sp. and Fusarium sp. The mycelial growth inhibition was estimated based on the antimicrobial activity testing of cultivation broth by the diffusion method. For the Aspergillus sp., the highest antifungal activity was recorded for the isolates Kro-4a and Mah-1a. In contrast, for the Fusarium sp., following 15 isolates exhibited the highest antagonistic effect Par-1, Par-2, Par-3, Par-4, Kup-4, Paš-1b, Pap-3, Kro-2, Kro-3a, Kro-3b, Kra-1a, Kra-1b, Šar-1, Šar-2b and Šar-4. One-way ANOVA was performed to determine the antagonists' effect statistical significance on inhibition zone diameter. Duncan's multiple range test was conducted to define homogenous groups of antagonists with the same level of statistical significance regarding their effect on antimicrobial activity of the tested cultivation broth against tested pathogens. The study results have pointed out the significant in vitro potential of the isolated strains to be used as biocontrol agents for the suppression of the tested mycotoxigenic fungi. Further research should include the identification and detailed characterization of the most promising isolates and mode of action of the selected strains as biocontrol agents. The following research should also involve bioprocess optimization steps to fully reach the selected strains' potential as microbial biopesticides and design cost-effective biotechnological production.

Keywords: Bacillus, biocontrol, bioprocess, mycotoxigenic fungi

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Authors: Getu Hailu, Catelynn Hettick, Niklas Pieper, Paul Kim, Augustine Hamner

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Airborne transmission is a problem that all viral respiratory diseases have in common. In late 2019, a disease outbreak, now known as SARS-CoV-2, suddenly expanded across China and the rest of the world in a matter of months. Research on the spread and transmission of SARS-CoV-2 airborne particles is ongoing, as well as the development of strategies for the prevention of the spread of these pathogens using indoor air quality (IAQ) methods. By evaluating the surface area of pollutants on the surface of a mannequin in a mock-based clinic room, this study aims to better understand how altering temperature and relative humidity affect aerosol spread and contamination. Four experiments were carried out at a constant temperature of 70 degrees Fahrenheit but with four different humidity levels of 0%, 30%, 45 percent, and 60%. The mannequin was placed in direct aerosol flow since it was discovered that this was the position with the largest exposed surface area. The findings demonstrate that as relative humidity increased while the temperature remained constant, the amount of surface area infected by virus particles decreased. These findings point to approaches to reduce the spread of viral particles, such as SARS-CoV-2 and emphasize the significance of IAQ controls in enclosed environments.

Keywords: IAQ, ventilation, COVID-19, humidity, temperature

Procedia PDF Downloads 159

Authors: Anjali Uday, Yuting Wang, Andres Alfonso Pena Olare

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The Discrete Element Method is a promising approach to modeling microscopic behaviors of granular materials. The quality of the simulations however depends on the model parameters utilized. The present study focuses on calibration and validation of the discrete element parameters for Cuxhaven sand based on the experimental data from triaxial and oedometer tests. A sensitivity analysis was conducted during the sample preparation stage and the shear stage of the triaxial tests. The influence of parameters like rolling resistance, inter-particle friction coefficient, confining pressure and effective modulus were investigated on the void ratio of the sample generated. During the shear stage, the effect of parameters like inter-particle friction coefficient, effective modulus, rolling resistance friction coefficient and normal-to-shear stiffness ratio are examined. The calibration of the parameters is carried out such that the simulations reproduce the macro mechanical characteristics like dilation angle, peak stress, and stiffness. The above-mentioned calibrated parameters are then validated by simulating an oedometer test on the sand. The oedometer test results are in good agreement with experiments, which proves the suitability of the calibrated parameters. In the next step, the calibrated and validated model parameters are applied to forecast the micromechanical behavior including the evolution of contact force chains, buckling of columns of particles, observation of non-coaxiality, and sample inhomogeneity during a simple shear test. The evolution of contact force chains vividly shows the distribution, and alignment of strong contact forces. The changes in coordination number are in good agreement with the volumetric strain exhibited during the simple shear test. The vertical inhomogeneity of void ratios is documented throughout the shearing phase, which shows looser structures in the top and bottom layers. Buckling of columns is not observed due to the small rolling resistance coefficient adopted for simulations. The non-coaxiality of principal stress and strain rate is also well captured. Thus the micromechanical behaviors are well described using the calibrated and validated material parameters.

Keywords: discrete element model, parameter calibration, triaxial test, oedometer test, simple shear test

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Authors: Jamie Lynn Co, Mary Shiela Ariola-Ramos

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Myroides are aerobic, yellow-pigmented, non-motile, non-fermenting gram-negative rods. They are commonly found in the environment such as water and soil. Although found in the environment, Myroides are rare pathogens of humans. Myroides spp. primarily infect immunocompromised patients, often with diabetes mellitus, liver cirrhosis, chronic kidney disease, chronic obstructive pulmonary disease or prolonged corticosteroid therapy. We present a case of a 70-year-old immunocompromised patient with diabetes mellitus, chronic renal failure, diagnosed with sepsis caused by Myroides spp. The primary portal and source of infection were the pustules and boils found on the lower extremities of the patient. Susceptibility testing showed that our isolate was only susceptible to ciprofloxacin and meropenem; and following the treatment, the patient recovered. Myroides continues to be a rare pathogen of humans that is prevalent in our environment. It primarily affects immunocompromised patients such as those with uncontrolled diabetes mellitus, chronic kidney disease, etc. Despite their low virulence, physicians should consider this opportunistic pathogen as possible etiologic agent especially in cases wherein there is lack of response to commonly used antibiotics.

Keywords: bacteremia, immunocompromised, gram negative rods, Myroides

Procedia PDF Downloads 162