Search results for: antibiotic resistance

Authors: Koon Weng Lau, Chee Dhang Chen, Abdul Aziz Azidah, Mohd Sofian-Azirun

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Recently, Sarawak state of Malaysia encounter an outbreak of dengue fever. Aedes albopictus has incriminated as one of the important vectors of dengue transmission. Without an effective vaccine, approaches to control or prevent dengue will be a focus on the vectors. The control of Aedes mosquitoes is still dependent on the use of chemical insecticides and insecticide resistance represents a threat to the effectiveness of vector control. This study was conducted to determine the resistance status of 11 active ingredients representing four major insecticide classes: DDT, dieldrin, malathion, fenitrothion, bendiocarb, propoxur, etofenprox, deltamethrin, lambda-cyhalothrin, cyfluthrin, and permethrin. Standard WHO test procedures were conducted to determine the insecticide susceptibility. Aedes albopictus collected from Kapit (resistance ratio, RR = 1.04–3.02), Kuching (RR = 1.17–4.61), and Sibu (RR = 1.06–3.59) exhibited low resistance toward all insecticides except dieldrin. This study reveled that dieldrin is still effective against Ae. albopictus, followed by fenitrothion, cyfluthrin, and deltamethrin. In conclusion, Ae. albopictus in Sarawak exhibited different resistance levels toward various insecticides and alternative solutions should be implemented to prevent further deterioration of the condition.

Keywords: Aedes albopictus, dengue, insecticide resistance, Malaysia

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Authors: Alireza Barari

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Physical activity and diet are factors that influence the body's structure. The purpose of this study was to compare the effects of four weeks of resistance training, and glutamine supplement consumption on growth hormone (GH), and Insulin-like growth factor 1 (IGF-1) Axis. 40 amateur male bodybuilders, participated in this study. They were randomly divided into four equal groups, Resistance (R), Glutamine (G), Resistance with Glutamine (RG), and Control (C). The R group was assigned to a four week resistance training program, three times/week, three sets of 10 exercises with 6-10 repetitions, at the 80-95% 1RM (One Repetition Maximum), with 120 seconds rest between sets), G group is consuming l-glutamine (0.1 g/kg^-1/day^-1), RG group resistance training with consuming L-glutamine, and C group continued their normal lifestyle without exercise training. GH, IGF1, IGFBP-III plasma levels were measured before and after the protocol. One-way ANOVA indicated significant change in GH, IGF, and IGFBP-III between the four groups, and the Tukey test demonstrated significant increase in GH, IGF1, IGFBP-III plasma levels in R, and RG group. Based upon these findings, we concluded that resistance training at 80-95% 1RM intensity, and resistance training along with oral glutamine shows significantly increase secretion of GH, IGF-1, and IGFBP-III in amateur males, but the addition of oral glutamine to the exercise program did not show significant difference in GH, IGF-1, and IGFBP-III.

Keywords: strength, glutamine, growth hormone, insulin-like growth factor 1

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Authors: S. M. A. Al-Qawabah, A. I. O. Zaid

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Aluminum and its alloys are versatile materials which are widely used in industrial and engineering applications due to their good and useful properties e.g. high strength to weight ratio, high thermal and electrical conductivities and good resistance to corrosion. However, against these favorable properties they have the disadvantage they solidifying large grain columnar structure which negatively affects their mechanical properties and surface quality. Aluminum alloys are normally grain refined by some alloying elements, such as Ti, Ti-B or Zr. In this paper, the effect of zirconium addition to Al grain refined by Ti after extrusion on its wear resistance is investigated under different loads and sliding speeds namely at 5,10 and 20 N loads and sliding speeds ranging from m/min. and m/min. the results are presented in three-dimensional wear mode. To the best the authors' knowledge, the wear of aluminum in 3-dimensions has never been tackled before. In this work, the wear resistance of by presenting the results of wear are presented and discussed on the time, load and speed plots.

Keywords: aluminum grain refined, addition of titanium, wear resistance, titanium

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Authors: B. Tayebani, N. Hosseinibalam, D. Mostofinejad

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Interest in using bacteria in cement materials due to its positive influences has been increased. Cement materials such as mortar and concrete basically suffer from higher porosity and water absorption compared to other building materials such as steel materials. Because of the negative side-effects of certain chemical techniques, biological methods have been proposed as a desired and environmentally friendly strategy for reducing concrete porosity and diminishing water absorption. This paper presents the results of an experimental investigation carried out to evaluate the influence of Sporosarcina pasteurii bacteria on the behaviour of two types of concretes (light weight aggregate concrete and normal weight concrete). The resistance of specimens to water penetration by testing water absorption and evaluating the electrical resistance of those concretes was examined and compared. As a conclusion, 20% increase in electrical resistance and 10% reduction in water absorption of lightweight aggregate concrete (LWAC) and for normal concrete the results show 7% decrease in water absorption and almost 10% increase in electrical resistance.

Keywords: bacteria, biological method, normal weight concrete, lightweight aggregate concrete, water absorption, electrical resistance

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Authors: Debjani Ghosh, Goutam Chowdhury, Prosenjit Samanta, Asish Kumar Mukhopadhyay

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Acute diarrhoea caused by diarrheagenic Escherichia coli (DEC) is one of the major public health problem in developing countries, mainly in Asia and Africa. DEC consists of six pathogroups, but the majority of the cases were associated with the three pathogropus, enterotoxigenic E. coli (ETEC), enteroaggregative E. coli (EAEC), and enteropathogenic E. coli (EPEC). Hence, we studied the prevalence and antimicrobial resistance of these three major DEC pathogroups in hospitalized diarrheal patients in Kolkata, India, during 2012-2019 with a large sample size. 8,891 stool samples were processed, and 7.8% of them was identified as DEC infection screened by multiplex PCR, in which ETEC was most common (47.7%) followed by EAEC (38.4%) and EPEC (13.9%). Clinical patient history suggested that children <5 years of age were mostly affected with ETEC and EAEC, whereas people within >5-14 years of age were significantly associated with EPEC and ETEC infections. Antibiogram profile showed a high prevalence of multidrug resistant (MDR) isolates among DEC (56.9%), in which 9% were resistant to antibiotics of six different antimicrobial classes. Screening of the antibiotic resistance conferring genes in DEC showed the presence of blaCTX-M (30.2%) in highest number followed by blaTEM (27.5%), tetB (18%), sul2 (12.6%), strA (11.8%), aadA1 (9.8%), blaOXA-1 (9%), dfrA1 (1.6%) and blaSHV (1.2%) which indicates the existence of mobile genetic elements in those isolates. Therefore, the presence of MDR DEC strains in higher number alarms the public health authorities to take preventive measures before the upsurge of the DEC caused diarrhea cases in near future.

Keywords: diarrheagenic escherichia coli, ETEC, EAEC, EPEC

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Authors: Abdulmagid A. Khattabi, Ahmed A. Hablous, Mofied M. Elnemry

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The carbon steel is of one of the most common mineral materials used in engineering and industrial applications in order to have access to the required mechanical properties, especially after the change of carbon ratio, but this may lead to stimulate corrosion. It has been used in models of solids with different carbon ratios such as 0.05% C, 0.2% C, 0.35% C, 0.5% C, and 0.65% C and have been studied using three testing durations which are 4 weeks, 6 weeks, and 8 weeks and among different corrosion environments such as atmosphere, fresh water, and salt water. This research is for the purpose of finding the effect of the carbon content on the corrosion resistance of steels in different corrosion medium by using the weight loss technique as a function of the corrosion resistance. The results that have been obtained through this research shows that a correlation can be made between corrosion rates and steel's carbon content, and the corrosion resistance decreases with the increase in carbon content.

Keywords: proportion of carbon in the steel, corrosion rate, erosion, corrosion resistance in carbon-steel

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Authors: Eyüp S. Akbas, Betul Ayaz, Beyza S. Haksever, Sema Basat

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We aimed to evaluate the relationship between insulin resistance, muscle mass and muscle strength in patients with Hepatitis B virus-related cirrhosis. In our study, there were 65 patients with hepatitis B virus-related cirrhosis in Child A and B group and 65 healthy control individual. Control group was chosen between patients who admitted to the internal medicine clinic and had no pathological values in a routine examination. Muscle mass index was calculated with bioimpedance analysis for both groups to determine muscle strength and muscle mass. Handgrip strength, arm, and calf circumference were measured. In both groups, HOMA-IR was calculated to determine insulin resistance. Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) value was detected 3,47±3,80 in the study group and 1,83±1,20 in control group. There were significant differences between the two groups in arm circumference, fasting insulin, fasting glucose, HOMA-IR, High-density lipoprotein (HDL) and total cholesterol parameters. The correlation coefficient between muscle mass and insulin resistance was statistically insignificant, especially in the study group. In healthy individuals group and all the groups, there wasn’t a correlation between muscle mass and insulin resistance. The upper limit for HOMA-IR was determined as 3,2. In control group, %78,9 of individuals were in HOMA-IR ( < 3.2) group and %21,1 of them were in ( ≥ 3,2) group. In study group, %68,3 of individuals were in HOMA-IR ( < 3,2) group and %31.7 were in HOMA-IR ( ≥ 3,2) group. In our study, we did not find a relationship between muscle mass and insulin resistance in patients with liver cirrhosis. In the study group, we detected a positive relationship between muscle mass, handgrip strength, and calf circumference. We did not find a relationship between insulin resistance and handgrip strength in our study.

Keywords: cirrhosis, hepatitis B, Insulin resistance, muscle mass

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Authors: Varsha Gupta, Priya Datta, Gursimran Mohi, Jagdish Chander

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Fluoroquinolones form the mainstay of therapy for the treatment of infections due to Salmonella enterica subsp. enterica. There is a complex interplay between several resistance mechanisms for quinolones and various fluoroquinolones discs, giving varying results, making detection and interpretation of fluoroquinolone resistance difficult. For detection of fluoroquinolone resistance in Salmonella ssp., we compared the use of pefloxacin and nalidixic acid discs as surrogate marker. Using MIC for ciprofloxacin as the gold standard, 43.5% of strains showed MIC as ≥1 μg/ml and were thus resistant to fluoroquinoloes. Based on the performance of nalidixic acid and pefloxacin discs as surrogate marker for ciprofloxacin resistance, both the discs could correctly detect all the resistant phenotypes; however, use of nalidixic acid disc showed false resistance in the majority of the sensitive phenotypes. We have also tested newer antimicrobial agents like cefixime, imipenem, tigecycline and azithromycin against Salmonella spp. Moreover, there was a comeback of susceptibility to older antimicrobials like ampicillin, chloramphenicol, and cotrimoxazole. We can also use cefixime, imipenem, tigecycline and azithromycin in the treatment of multidrug resistant S. typhi due to their high susceptibility.

Keywords: salmonella, pefloxacin, surrogate marker, chloramphenicol

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Authors: Mohamed Mahdi Alshahni, Takashi Tamura, Koichi Makimura

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Objective: The objective of this study is to evaluate roles of ABC-type efflux transporters in the resistance of Candida auris against common antifungal agents. Material and Methods: A wild-type C. auris strain and its antifungal resistant derivative strain that is generated through induction by antifungal agents were used in this study. The strains were cultured onto media containing beauvericin alone or in combination with azole agents. Moreover, expression levels of four ABC-type transporter’s homologs in those strains were analyzed by real time PCR with or without antifungal stress by fluconazole or voriconazole. Results: Addition of beauvericin helped to partially restore the susceptibility of the resistant strain against fluconazole, suggesting participation of ABC-type transporters in the resistance mechanism. Real time PCR results showed that mRNA levels of three out of the four analyzed transporters in the resistant strain were more than 2-fold higher than their counterparts in the wild-type strain under negative control and antifungal agent-containing conditions. Conclusion: C. auris is an emerging multidrug-resistant pathogen causing human mortality worldwide. Providing effective treatment has been hampered by the resistance to antifungal drugs, demanding understanding the resistance mechanism in order to devise new therapeutic strategies. Our data suggest a partial contribution of ABC-type transporters to the resistance of this pathogen.

Keywords: resistance, C. auris, transporters, antifungi

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Authors: Hadi Rouhi Belvirdi

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Reinforced concrete structures, in addition to bearing service loads and seismic effects, may also be subjected to impact loads resulting from unforeseen incidents. Understanding the behavior of these structures is crucial, as they serve to protect against such sudden loads and can significantly reduce damage and destruction. In examining the behavior of structures under such loading conditions, a total of eight specimens of single-layer reinforced concrete slabs were subjected to impact loading through the free fall of weights from specified heights. The weights and dimensions of the specimens were uniform, and the amount of reinforcement was consistent. By altering the slabs' overall shape and the reinforcement details, efforts were made to optimize the behavior of the slabs against impact loads. The results indicated that utilizing ductile features in the slabs increased their resistance to impact loading. However, the compressive strength of the reinforcement did not significantly enhance the flexural resistance. Assuming a constant amount of longitudinal steel, changes in the placement of tensile reinforcement led to a decrease in resistance. With a fixed amount of transverse steel, merely adjusting the angle of the transverse reinforcement could help control cracking and mitigate premature failures. An increase in compressive resistance beyond a certain limit resulted in local buckling of the compressive zone, subsequently decreasing the impact resistance.

Keywords: reinforced concrete slab, high-strength concrete, impact loading, impact resistance

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Authors: Ahmed Y. Kutbi, C. Russell. J. Baird, M. McNaughtan, Francis Wayman

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Wastewaters from antibiotic production facilities are characterized with high concentrations of dissolved organic substances. Subsequently, it challenges wastewater treatment plant operator to achieve successful biological treatment and to meet regulatory emission levels. Of the dissolved organic substances, this research is investigating the fate of organic nitrogenous compounds (i.e., Chitin) in an antibiotic production wastewater treatment plant located in Irvine, Scotland and its impact on the WWTP removal performance. Dissolved organic nitrogen (DON) in WWTP effluents are of significance because 1) its potential to cause eutrophication in receiving waters, 2) the formation of nitrogenous disinfection by products in drinking waters and 3) limits WWTPs ability to achieve very low total nitrogen (TN) emissions limits (5 – 25 mg/l). The latter point is where the knowledge gap lays between the operator and the regulator in setting viable TN emission levels. The samples collected from Irvine site at the different stages of the treatment were analyzed for TN and DON. Results showed that the average TN in the WWTP influents and effluents are 798 and 261 mg/l respectively, in other words, the plant achieved 67 % removal of TN. DON Represented 51% of the influents TN, while the effluents accounted 26 % of the TN concentrations. Therefore, an ongoing investigation is carried out to identify DON constituents in WWTP effluent and evaluate its impact on the WWTP performance and its potential bioavailability for algae in receiving waters, which is, in this case, Irvine Bay.

Keywords: biological wastewater treatment plant, dissolved organic nitrogen, bio-availability, Irvine Bay

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Authors: W. Hajuthman, R. Warner, S. Rahman, M. Abraham, H. Helliwell, D. Bodiwala

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Context: Prostate cancer is a prevalent cancer in males in Europe and the US, with diagnosis primarily relying on PSA testing, mpMRI, and subsequent biopsies. However, this diagnostic strategy may lead to complications for patients. Research Aim: The aim of this study is to assess compliance with trust guidelines for antibiotic prophylaxis in patients undergoing transperineal template biopsies of the prostate and evaluate the rate of post-procedure complications. Methodology: This study is conducted retrospectively over an 8-month period. Data collection includes patient demographics, compliance with trust guidelines, associated risk factors, and post-procedure complications such as infection, haematuria, and urinary retention. Findings: The audit includes 100 patients with a median age of 66.11. The compliance with pre-procedure antibiotics was 98%, while compliance with antibiotic prophylaxis recommended by trust guidelines was 68%. Among the patients, 3% developed post-procedure sepsis, with 2 requiring admission for intravenous antibiotics. No evident risk factors were identified in these cases. Additionally, post-procedure urinary retention occurred in 3% of patients and post-procedure haematuria in 2%. Theoretical Importance: This study highlights the increasing use of transperineal template biopsies across UK centres and suggests that having a standardized protocol and compliance with guidelines can reduce confusion, ensure appropriate administration of antibiotics, and mitigate post-procedure complications. Data Collection and Analysis Procedures: Data for this study is collected retrospectively, involving the extraction and analysis of relevant information from patient records over the specified 8-month period. Question Addressed: This study addresses the following research questions: (1) What is the compliance rate with trust guidelines for antibiotic prophylaxis in transperineal template biopsies of the prostate? (2) What is the rate of post-procedure complications, such as infection, haematuria, and urinary retention? Conclusion: Transperineal template biopsies are becoming increasingly prevalent in the UK. Implementing a standardized protocol and ensuring compliance with guidelines can reduce confusion, ensure proper administration of antibiotics, and potentially minimize post-procedure complications. Additionally, considering that studies show no difference in outcomes when prophylactic antibiotics are not used, the reminder to follow trust guidelines may prompt a re-evaluation of antibiotic prescribing practices.

Keywords: prostate, transperineal template biopsies of prostate, antibiotics, complications, microbiology, guidelines

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Authors: Sayyed-javad Ziaolhagh, Ali-Reza Saadatifar

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Introduction: Athletes frequently perform anabolic steroid resistance exercise, but the effects of medical doses and abuse along with resistance exercise on structural damage to the Pancreases and also jujube extract are unknown. The aim of this study was to investigate the effects of resistance training on body weight and hip fractures induced by boldenone injection in male rats. Materials and methods: In this experimental study, 30 male Wistar rats aged 8-12 weeks (weight 202±9.34 g) were randomly divided into five groups: control, boldenone, extract of iujuba+boldenone, boldenone+resistance training and boldenone+resistance training +extract of jujuba. The resistance training program included climbing the ladder for 8 weeks, 3 days a week, 1 session training in a day and each session consisted of the 3 sets and 5 repetitions. Injection was conducted in depth in the hamstring once a week on an appointed day. After anesthesia, autopsy was performed, and the cardiac tissue was isolated. Results: Results showed that boldenone caused tissue damage, congestion, and nuclei unclear and diffuse. In the group "resistance + Boldenone," The Pancreases tissue showed a high degree of hyperemia, and the muscle cells were somewhat abnormal. In boldenone + jujube, the appearance of the tissue was normal, and the rejuvenating effect was visible. Conclusion: Boldenone appears to cause structural damage to the Pancreases tissue. Strength training with Jujube Extract can reduce part of the pancreatic system disorders (necrosis and inflammation) caused by anabolic steroid use.

Keywords: boldenone, Jujube extract, pancreases tissue, resistance training

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Authors: Chung-Yang Chuang, Chi-Lung Chen, Hui-Min Wang, Chang-Jung Chang

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Conductive fiber is the key material for e-textiles and wearable devices. However, the durability of the conductive fiber after the wash process is an important issue for conductive fiber applications in e-textiles. Therefore, it is necessary for conductive fiber with good performance on electrically conductive behavior during the product life cycle. In this research, the PET-based conductive fiber was prepared by silver conductive ink continuous coating. The conductive fiber showed low fiber resistance (10-¹~10Ω/cm), and the conductive behavior still had good performance (fiber resistance:10-¹~10Ω/cm， percentage of fiber resistance change:<60%) after the water wash durability test (AATCC-135， 30 times). This research provides a better solution to resolve the issues of resistance increase after the water wash process due to the damage to the conductive fiber structure.

Keywords: PET, conductive fiber, e-textiles, wearable devices

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Authors: Wissem Abdaoui, Ilhem Mokhtari, Adel Gouri, Benouareth Djamel Eddine

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Contracted in a health facility, hospital-acquired infections are a major public health problem in recent years. The increase of nosocomial infections is partly related to diagnostic and therapeutic advances in medicine. The aim of our study was to isolate and diagnose some types of bacteria that are circulating in the hospital by performing different samples at two medical services: Pulmonary and Infectious Diseases. The antibiotic susceptibility tests were performed for bacterial isolates. The results have shown that there is a predominance of enterobacteria followed by the staphylococcus with its two species epidermidis ans saprophyticus. The study of the antibiogramme identified that some of these bacteria have a resistant profile against all the tested antibiotics. The fight against nosocomial infections is difficult because it must act on several factors: quality of care, safety of the hospital environment, hygiene, wearing gloves etc. are all areas that should be of heightened vigilance and preventive measures.

Keywords: nosocomial infection, isolation, identification, sensitivity and resistance to antibiotics

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Authors: B. Chandar, M. K. Ramasamy, P. Madasamy

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The discovery and development of newer antibiotics are limited with the increase in resistance of such multi-drug resistant bacteria creating the need for alternative new therapeutic agents. The recently discovered New Delhi Metallo-betalactamase-1 (NDM-1), which confers antibiotic resistance to most of the currently available β-lactams, except colistin and tigecycline, is a global concern. Several antibacterial drugs approved are natural products or their semisynthetic derivatives, but plant extracts remain to be explored to find molecules that are effective against NDM-1 bacteria. Therefore, it is necessary to explore the possibility of finding new and effective antibacterial compounds against NDM-1 bacteria. In the present study, we have screened a diverse set South Indian plant species, and report most plant species as a potential source for antimicrobial compounds against NDM-1 bacteria. Ethanol extracts from the leaves of taxonomically diverse South Indian medicinal plants were screened for antibacterial activity against NDM-1 E. coli using streak plate method. Among the plant screened against NDM-1 E. coli, the ethanol extracts from many plant extracts showed minimum bactericidal concentration between 5 and 15 mg /ml and MIC between 2.54 and 5.12 mg/ml. These extracts also showed a potent synergistic effect when combined with antibiotics colistin and tetracycline. Combretum albidum that was effective was taken for further analysis. At 5mg/L concentration, these extracts inhibited the NDM-1 enzyme in vitro, and residual activity for Combretum albidum was 33.09%. Treatment of NDM-1 E. coli with the extracts disrupted the cell wall integrity and caused 89.7% cell death. The plant extract of Combretum albidum that was effective was subjected to fractionation and the fraction was further subjected to HPLC, LC-MS for identification of antibacterial compound.

Keywords: antibacterial activity, combretum albidum, Escherichia coli, NDM-1

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Authors: Nadir Ayrilmis

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Wood and wood-based panels are one of the oldest structural materials used in the construction industry due to their significant advantages such as good mechanical properties, low density, renewable material, low-cost, recycling, etc. However, they burn when exposed to a flame source or high temperatures. This is very important when the wood products are used as structural or hemi-structural materials in the construction industry, furniture industry, so on. For this reason, the fire resistance is demanded property for wood products. They can be impregnated with fire retardants to improve their fire resistance. The most used fire retardants, fire-retardant mechanism, and fire-testing systems, and national and international fire-durability classifications and standard requirements for fire-durability of wood and wood-based panels were given in this study.

Keywords: fire resistance, wood-based panels, cone calorimeter, wood

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Authors: Sima E. Rugarabamu, Mecky I. Matee, Elison N. M. Simon

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Background: In Tanzania bacteriological studies of etiological agents of oro-facial infections are very limited, and very few have investigated anaerobes. The aim of this study was to determine the spectrum of bacterial agents involved in oral and maxillofacial infections in patients attending Muhimbili National Hospital, Dar-es-salaam, Tanzania. Method: This was a hospital based descriptive cross-sectional study that was conducted in the Department of Oral and Maxillofacial Surgery of the Muhimbili National Hospital in Dar es Salaam, Tanzania from 1st January 2014 to 31st August 2014. Seventy (70) patients with various forms of oral and maxillofacial infections who were recruited for the study. The study participants were interviewed using a prepared questionnaire after getting their consent. Pus aspirate was cultured on Blood agar, Chocolate Agar, MacConkey agar and incubated aerobically at 37°C. Imported blood agar was used for anaerobic culture whereby they were incubated at 37°Cin anaerobic jars in an atmosphere of generated using commercial gas-generating kits in accordance with manufacturer’s instructions. Plates were incubated at 37°C for 24 hours (For aerobic culture and 48 hours for anaerobic cultures). Gram negative rods were identified using API 20E while all other isolates were identified by conventional biochemical tests. Antibiotic sensitivity testing for isolated aerobic and anaerobic bacteria was detected by the disk diffusion, agar dilution and E-test using routine and commercially available antibiotics used to treat oral facial infections. Results: This study comprised of 41 (58.5%) males and 29 (41.5%) females with a mean age of 32 years SD +/-15.1 and a range of 19 to 70 years. A total of 161 bacteria strains were isolated from specimens obtained from 70 patients which were an average of 2.3 isolates per patient. Of these 103 were aerobic organism and 58 were strict anaerobes. A complex mix of strict anaerobes and facultative anaerobes accounted for 87% of all infections.The most frequent aerobes isolated was streptococcus spp 70 (70%) followed by Staphylococcus spp 18 (18%). Other organisms such as Klebsiella spp 4 (4%), Proteus spp 5 (5%) and Pseudomonas spp 2 (2%) were also seen. The anaerobic group was dominated by Prevotella spp 25 (43%) followed by Peptostreptococcus spp 18 (31%); other isolates were Pseudomonas spp 2 (1%), black pigmented Pophyromonas spp 4 (5%), Fusobacterium spp 3 (3%) and Bacteroides spp 5 (8%). Majority of these organisms were sensitive to Amoxicillin (98%), Gentamycin (89%), and Ciprofloxacin (100%). A 40% resistance to metronidazole was observed in Bacteroides spp otherwise this drug and others displayed good activity against anaerobes. Conclusions: Oral and maxillofacial facial infections at Muhimbili National Hospital are mostly caused by streptococcus spp and Prevotella spp. Strict anaerobes accounted for 36% of all isolates. The profile of isolates should assist in selecting empiric therapy for infections of the oral and maxillofacial region. Inclusion of antimicrobial agents against anaerobic bacteria is highly recommended.

Keywords: bacteria, oral and maxillofacial infections, antibiotic susceptibility, Tanzania

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Authors: Ziya Esen, Özgür Duygulu, Nazlı S. Büyükatak

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This study investigates the effects of aging heat treatment on corrosion resistance and mechanical properties of WE43 Magnesium alloy. The heat treatment of alloys was conducted by solutionizing at 525oC for 16 h, followed by aging at 190, 210 and 230oC for up to 48 h. The type and the size of precipitates formed upon aging have influenced both the mechanical properties and corrosion behavior of the alloy. Solutionized alloy displayed the worst corrosion resistance in simulated body fluid, while peak hardness and the best corrosion resistance were observed in the alloy aged at 210oC for 24 h as a result of β’ precipitate formation. Longer aging duration at 210oC decreased the corrosion rate due to the coarsening of the precipitates and formation of precipitate-free zones. The increased corrosion resistance of the peak aged samples was attributed to the slowing down effect of the Mg(OH)₂/MgO corrosion layer by the pinning effect of β’-precipitates.

Keywords: WE43 magnesium alloy, simulated body fluid, corrosion, mechanical properties

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Authors: Alok Kumar Kamal, Vinod Kumar

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The trench gate MOSFET has shown itself as the most appropriate power device for low to medium voltage power applications due to its lowest possible ON resistance among all power semiconductor devices. In this research work a double-epilayer PSGT structure using a thin layer of N+ polysilicon as gate material. The total ON-state resistance (RON) of UMOSFET can be reduced by optimizing the epilayer thickness. The optimized structure of Double-Epilayer exhibits a 25.8% reduction in the ON-state resistance at Vgs=5V and improving the switching characteristics by reducing the Reverse transfer capacitance (Cgd) by 7.4%.

Keywords: Miller-capacitance, double-Epilayer;switching characteristics, power trench MOSFET (U-MOSFET), on-state resistance, blocking voltage

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Authors: Mai. M. Toughan, Ahmed A. A. Sallam, Ashraf O. Abd El-Latif

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Termites are eusocial insects that are found on all continents except Antarctica. Termites have serious destructive impact, damaging local huts and crops of poor subsistence. The annual cost of termite damage and its control is determined in the billions globally. In Egypt, most of these damages are due to the subterranean termite species especially the sand termite, P. hypostoma. Pyrethroids became the primary weapon for subterranean termite control, after the use of chlorpyrifos as a soil termiticide was banned. Despite the important role of pyrethroids in termite control, its extensive use in pest control led to the eventual rise of insecticide resistance which may make many of the pyrethroids ineffective. The ability to diagnose the precise mechanism of pyrethroid resistance in any insect species would be the key component of its management at specified location for a specific population. In the present study, detailed toxicological and biochemical studies was conducted on the mechanism of pyrethroid resistance in P. hypostoma. The susceptibility of field populations of P. hypostoma against deltamethrin, α-cypermethrin and ƛ-cyhalothrin was evaluated. The obtained results revealed that the workers of P. hypostoma have developed high resistance level against the tested pyrethroids. Studies carried out through estimation of detoxification enzyme activity indicated that enhanced esterase and cytochrome P450 activities were probably important mechanisms for pyrethroid resistance in field populations. Elevated esterase activity and also additional esterase isozyme were observed in the pyrethroid-resistant populations compared to the susceptible populations. Strong positive correlation between cytochrome P450 activity and pyrethroid resistance was also reported. |Deltamethrin could be recommended as a resistance-breaking pyrethroid that is active against resistant populations of P. hypostoma.

Keywords: Psammotermes hypostoma, pyrethroid resistance, esterase, cytochrome P450

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Authors: Masoud Baghalian, Musa Arshad

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In order to investigate the effect of foliar application of calcium chloride on the resistance of fruits such as Red and Golden Lebanese apple varieties to blue mold, a split plot experiment in time and space, based on accidental blocks, with three replications under foliar application were done (Control, one in a thousand, two in thousands) and the results of the variance analysis showed that there is a significant difference between the levels of foliar and variety at 5% level and between time, there is significant difference in interaction of variety × time and three way interaction of foliar×variety×time, at 1% level. The highest resistance to the blue mold disease in foliar application was observed at two in thousands calcium (calcium chloride) level.

Keywords: apple, blue mold, foliar calcium, resistance

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Authors: Seyed Abolhasan Naeini, Mohammad Mahdi Shojaedin

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Oil leakage from the pipelines and the tanks carrying them, or during oil extraction, could lead to the changes in the characteristics and properties of the soil. In this paper, conducting a series of experimental cyclic triaxial tests, the effects of oil contamination on the liquefaction potential of sandy soils is investigated. The studied specimens are prepared by mixing the Firoozkuh sand with crude oil in 4, 8 and 12 percent by soil dry weight. The results show that the oil contamination up to 8% causes an increase in the soil liquefaction resistance and then with increase in the contamination, the liquefaction resistance decreases.

Keywords: cyclic triaxial test, liquefaction resistance, oil contamination, sandy soil

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Authors: Seree Klaengair, Sunpetch Angkititrakul, Dusadee Phongaran, Chaiyaporn Soikum

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The objectives of this study is to determine the prevalence and antimicrobial resistance pattern of Salmonella spp. isolated from chickens at slaughterhouses in northeast of Thailand. During 2015-2016, all samples were isolated and identified by ISO 6579:2002. A total of 604 samples of rectal swab were collected and isolated for the presence of Salmonella. Salmonella was detected in 109 of 604 (18.05%) samples. The most prevalent serovars were Salmonella Kentucky (22.94%), Give (20.18%) and Typhimurium (7.34%). In this study, 66.97% of the isolates were resistant to at least one antimicrobial drug and 38.39% were multidrug resistant. The highest resistances were found in nalidixic acid (49.54%), ampicillin (30.28%), tetracycline (27.52%), amoxicillin (26.61%), ciprofloxacin (23.85) and norfloxacin (19.27%). The results showed high prevalence of Salmonella spp. in chickens and antimicrobial resistance patterns. Prevention and control of Salmonella contamination in chickens should be consumer healthy.

Keywords: antimicrobial resistance, Salmonella spp., chicken, slaughterhouse

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Authors: Jihane Abdessadak, Hicham Achelhi, Kamal Reklaoui

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For any company or organization, change must be natural and binding in order to evolve its business, protect its durability and remain competitive. "Adapt or disappear". But how often managers, leaders or employees develop astonishing ideas that could improve several aspects of the organization and the feedback is less that encouraging and people give unrealistic judgments just to escape change. In this paper, we are going to discuss what we do know about change and resistance to change and what we can do to tame this phenomenon and, above all, the main steps that can follow an idea man in the delicate and decisive implementation of innovations.

Keywords: innovation, change, resistance to change/innovation, barriers to innovation, levers of innovation

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Authors: Yasser M. Abd-elrhman, Mohamed A. Gepreel, Kiochi Nakamura, Ahmed Abd El-Moneim, Sengo Kobayashi, Mervat M. Ibrahim

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Titanium alloys are known as highly bio compatible metallic materials due to their high strength, low elastic modulus, and high corrosion resistance in biological media. Besides other important material features, the corrosion parameters and corrosion products are responsible for limiting the biological and chemical bio compatibility of metallic materials that produce undesirable reactions in implant-adjacent and/or more distant tissues. Electrochemical corrosion behaviors of novel beta titanium alloys, Ti-4.7Mo-4.5Fe, Ti-3Mo-0.5Fe, and Ti-2Mo-0.5Fe were characterized in naturally aerated Ringer’s solution at room temperature compared with common used biomedical titanium alloy, Ti-6Al-4V. The corrosion resistance of titanium alloys were investigated through open circuit potential (OCP), potentiodynamic polarization measurements and optical microscope (OM). A high corrosion resistance was obtained for all alloys due to the stable passive film formed on their surfaces. The new present alloys are promising metallic biomaterials for the future, owing to their very low elastic modulus and good corrosion resistance capabilities.

Keywords: titanium alloys, corrosion resistance, Ringer’s solution, electrochemical corrosion

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Authors: Pauline Ribert, Gaelle Roudaut, Sebastien Dupont, Laurent Beney

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Yeasts, anhydrobiotic organisms, can survive extreme water disturbances, thanks to the prolonged and reversible suspension of their cellular activity as well as the establishment of a defense arsenal. This property is exploited by many industrialists. One of the protection systems implemented by yeast is the vitrification of its cytoplasm by trehalose. The thermal resistance of dry yeasts is a crucial parameter for their use. However, studies on the thermal resistance of dry yeasts are often based on yeasts produced in laboratory conditions with non-optimal drying processes. We, therefore, propose a study on the thermal resistance of industrial dry yeasts in relation to their thermophysical properties. Heat stress was applied at three temperatures (50, 75, and 100°C) for 10, 30, or 60-minute treatments. The survival of yeasts to these treatments was estimated, and their thermophysical properties were studied by differential scanning calorimetry. The industrial dry yeasts resisted 60 minutes at 50°C and 75°C and 10 minutes at a temperature close to 100°C. At 100°C, yeast was above their glass transition temperature. Industrial dry yeasts are therefore capable of withstanding high thermal stress if maintained in a specific thermophysical state.

Keywords: dry yeast, glass transition, thermal resistance, vitrification

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Authors: Sreeja Shaw, Prosenjit Samanta, Asish Kumar Mukhopadhyay

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Cholera is still a global public health burden and is caused by Vibrio cholerae O1 and O139 serogroups. Evidence from recent outbreaks in Haiti and Yemen suggested that circulating V. cholerae O1 El Tor variant strains are continuously changing to cause more ruinous outbreaks worldwide, and most of them have emerged from the Indian subcontinents. Therefore, we studied the changing virulence characteristics along with the antibiotic resistance profile of V. cholerae O1strains isolated from seasonal outbreaks in three cholera endemic regions during 2018, Gujarat and Maharashtra in Western India (87 strains), and to compare those features with the isolates of West Bengal in Eastern India (48 strains) collected during the same period. All the strains from Western India were of Ogawa serotype, polymyxin B-sensitive, hemolytic, and contained a large fragment deletion in VSP-II genomic region similar with Yemen outbreak strains and carried more virulent Haitian genetic alleles of major virulence associated genes ctxB, tcpA, and rtxA. Conversely, 14.6% (7/48) of the strains from Eastern India were belong to the Inaba serotype, polymyxin B-resistant, non-hemolytic, harbored intact VSP-II region, classical ctxB, Haitian tcpA, and El Tor rtxA alleles. Interestingly, resistance to tetracycline and chloramphenicol was seen in isolates from both regions, which are not very common among V. cholerae O1 isolates in India. Therefore, this study indicated West Bengal as a diverse region where two different types of El Tor variant hypervirulent strains are co-existed, probably competing for their better environmental survival, which may result in severe irrepressible disease outcome in the future.

Keywords: cholera, vibrio cholerae, polymyxin B, Non-hemolytic, ctxB, tcpA, rtxA, VSP-II

Procedia PDF Downloads 166

Authors: Evelyn Osehontue Uroro, Richard Bright, Jing Yang Quek, Krasimir Vasilev

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Bacterial infections have been a challenge both in the public and private sectors. The colonization of bacteria often occurs in medical devices such as catheters, heart valves, respirators, and orthopaedic implants. When biomedical devices are inserted into patients, the deposition of macromolecules such as fibrinogen and immunoglobin on their surfaces makes it easier for them to be prone to bacteria colonization leading to the formation of biofilms. The formation of biofilms on medical devices has led to a series of device-related infections which are usually difficult to eradicate and sometimes cause the death of patients. These infections require surgical replacements along with prolonged antibiotic therapy, which would incur additional health costs. It is, therefore, necessary to prevent device-related infections by inhibiting the formation of biofilms using intelligent technology. Antibiotic resistance of bacteria is also a major threat due to overuse. Different antimicrobial agents have been applied to microbial infections. They include conventional antibiotics like rifampicin. The use of conventional antibiotics like rifampicin has raised concerns as some have been found to have hepatic and nephrotoxic effects due to overuse. Hence, there is also a need for proper delivery of these antibiotics. Different techniques have been developed to encapsulate and slowly release antimicrobial agents, thus reducing host cytotoxicity. Examples of delivery systems are solid lipid nanoparticles, hydrogels, micelles, and polymeric nanoparticles. The different ways by which drugs are released from polymeric nanoparticles include diffusion-based release, elution-based release, and chemical/stimuli-responsive release. Polymeric nanoparticles have gained a lot of research interest as they are basically made from biodegradable polymers. An example of such a biodegradable polymer is polycaprolactone (PCL). PCL degrades slowly by hydrolysis but is often sensitive and responsive to stimuli like enzymes to release encapsulants for antimicrobial therapy. This study presents the synthesis of PCL nanoparticles loaded with rifampicin and the on-demand release of rifampicin for treating staphylococcus aureus infections.

Keywords: enzyme, Staphylococcus aureus, PCL, rifampicin

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Authors: Nacéra Benoussaid, Lehalali Meriem, Benchabane Messaoud

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Our work focuses on the production of compound antibiotic effect of volatile nature namely hydrogen cyanide and the production and identification of molecules phénazinique by some strains of fluorescent Pseudomonas spp isolated from the rhizosphere of some trees for a possible use as bio pesticides antifungal effect and/or antibiotic. We tested the production of hydrogen cyanide of 21 strains of Pseudomonas spp. fluorescent among them 19 strains (90, 47%) showed a positive cyanogenesis.The antagonism test executed in vitro showed that Pseudomonas strains have a higher anti fungal effect relative to their antibacterial effect with diameters of inhibition zones up to 3, 9 cm recorded by the strain F48 against Coleosporiumsp compared with recorded results against bacteria with a maximum inhibition of 1, 26 cm among this antagonistic strain.Three strains were selected by testing for producing phénazines namely PI9, BB9 and F20. The effect of the antimicrobial activity was performed on different culture media (GN, King B, ISP2 and PDA). The results of our study allowed us to retain the King B medium as ideal medium for the production of secondary metabolite. The produced phenazinique compounds was extracted from various organic solvents, and after the results of antibiographie against germs - targets, the extracts of ethyl acetate gave the best results compared to dichloromethane and hexane.The Analysis of these compounds of antibiotic phenazinique effect within layer chromatography (CCM) and high performance liquid chromatography( HPLC) indicate that both strains PI9 and F20 are productive of phenazine-1-carboxylic acid (PCA). The BB9 strain is suspected to be productive of another phenazinique compound.

Keywords: Pseudomonas ssp. fluorescents, antagonism in vitro, secondary metabolite, phenazines, biopesticide.

Procedia PDF Downloads 511