Search results for: blast resistance

Authors: Saheed O. Akinwale, Olufemi A. Koya

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Based on the need to modify palm kernel shell (PKS) and coconut shell (CNS) for some engineering applications, the study evaluated some physical characteristics and fracture resistance, relevant in estimating energy requirements in comminution of the nutshells. The shells, obtained from local processing mills, were washed, sun-dried and sorted to remove kernels, nuts and other extraneous materials. Experiments were then conducted to determine the thickness, density, moisture content, and hardness of the shells. Fracture resistances were characterised by the average compressive load, stiffness and toughness at bio-yield point of specially prepared section of the shells, under quasi-static compression loading. The densities of the dried PKS at 7.12% and the CNS at 6.47% (wb) moisture contents were 1291.20 and 1247.40 kg/m3, respectively. The corresponding Brinnel Hardness Numbers were 58.40 ± 1.91 and 56.33 ± 4.33. Close shells thickness of both PKS and CNS exhibited identical physical properties although; CNS is relatively larger in physical dimensions than PKS. The findings further showed that both shell types exhibited higher resistance with compression along the longitudinal axes than the transverse axes. With compressions along the longitudinal axes, the fracture force were 1.41 ± 0.11 and 3.62 ± 0.09 kN; bio-stiffness; 934.70 ± 67.03 kN/m and 1980.74 ± 8.92 kN/m; and toughness, 2.17 ± 0.16 and 6.51 ± 0.15 KN mm for the PKS and CNS, respectively. With the estimated toughness of CNS higher than that of PKS, the study showed the requirement of higher comminution energy for CNS.

Keywords: bio-stiffness, coconut shell, comminution, crushing strength, energy requirement, palm kernel shell, toughness

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Authors: Asrat Agalu Abejew

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Background: Antimicrobial resistance (AMR) is a silent tsunami and one of the top global threats to health care and public health. It is one of the common agendas globally and in Ethiopia. Emerging AMR will be a double burden to Ethiopia, which is facing a series of problems from infectious disease morbidity and mortality. In Ethiopia, although there are attempts to document AMR in healthcare institutions, comprehensive and all-inclusive analysis is still lacking. Thus, this study is aimed to determine trends in AMR from 2016-2021. Methods: A retrospective analysis of secondary data recorded in the Amhara Public Health Institute (APHI) from 2016 to 2021 G.C was conducted. Blood, Urine, Stool, Swabs, Discharge, body effusions, and other Microbiological specimens were collected from each study participants, and Bacteria identification and Resistance tests were done using the standard microbiologic procedure. Data was extracted from excel in August 2022, Trends in AMR were analyzed, and the results were described. In addition, the chi-square (X2) test and binary logistic regression were used, and a P. value < 0.05 was used to determine a significant association. Results: During 6 years period, there were 25143 culture and susceptibility tests. Overall, 265 (46.2%) bacteria were resistant to 2-4 antibiotics, 253 (44.2%) to 5-7 antibiotics, and 56 (9.7%) to >=8 antibiotics. The gram-negative bacteria were 166 (43.9%), 155 (41.5%), and 55 (14.6%) resistant to 2-4, 5-7, and ≥8 antibiotics, respectively, whereas 99(50.8%), 96(49.2% and 1 (0.5%) of gram-positive bacteria were resistant to 2-4, 5-7 and ≥8 antibiotics respectively. K. pneumonia 3783 (15.67%) and E. coli 3199 (13.25%) were the most commonly isolated bacteria, and the overall prevalence of AMR was 2605 (59.9%), where K. pneumonia 743 (80.24%), E. cloacae 196 (74.81%), A. baumannii 213 (66.56%) being the most common resistant bacteria for antibiotics tested. Except for a slight decline during 2020 (6469 (25.4%)), the overall trend of AMR is rising from year to year, with a peak in 2019 (8480 (33.7%)) and in 2021 (7508 (29.9%). If left un-intervened, the trend in AMR will increase by 78% of variation from the study period, as explained by the differences in years (R2=0.7799). Ampicillin, Augmentin, ciprofloxacin, cotrimoxazole, tetracycline, and Tobramycin were almost resistant to common bacteria they were tested. Conclusion: AMR is linearly increasing during the last 6 years. If left as it is without appropriate intervention after 15 years (2030 E.C), AMR will increase by 338.7%. A growing number of multi-drug resistant bacteria is an alarm to awake policymakers and those who do have the concern to intervene before it is too late. This calls for a periodic, integrated, and continuous system to determine the prevalence of AMR in commonly used antibiotics.

Keywords: AMR, trend, pattern, MDR

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Authors: Nioushasadat Haji Seyed Javadi, Ailar Hajimohammadi, Nasser Khalili

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Currently, the recycling of plastic wastes has been the subject of much research attention, especially in pavement constructions, where virgin polymers can be replaced by recycled plastics for asphalt binder modification. Among the plastic types, recycled linear low-density polyethylene (RLLDPE) has been one of the common and largely available plastics for bitumen modification. However, it is important to note that during the recycling process, LLDPE can easily be contaminated with other plastic types, especially with low-density polyethylene (LDPE), high-density polyethylene (HDPE), and polypropylene (PP). The cross-contamination of LLDPE with other plastics lowers its quality and, consequently, can affect the asphalt modification process. This study aims to assess the effect of LLDPE cross-contamination on bitumen modification. To do so, samples of bitumen modified with LLDPE and blends of LLDPE with LDPE, HDPE, and PP were prepared and compared through physical and rheological evaluations. The experimental tests, including softening point, penetration, viscosity at 135 °C, and dynamic shear rheometer, were conducted. The results indicated that the effect of cross-contamination on softening point and rutting resistance was negligible. On the other side, penetration and viscosity were highly impacted. The results also showed that among contamination of LLDPE with the other plastic types, PP had the highest influence in comparison with HDPE and LDPE on changing the properties of the LLDPE- modified bitumen.

Keywords: recycled polyethylene, polymer cross-contamination, waste plastic, bitumen, rutting resistance

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Authors: Maryam Beiranvand

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Multi-drug resistance in various microorganisms has increased globally in many healthcare facilities. Less effective antimicrobial activity of drug therapies for infection control becomes trouble. Since 1980, no new type of antimicrobial drug has been identified, even though combinations of antibiotic drugs have been discovered almost every decade. Between 1981 and 2006, over 70% of novel pharmaceuticals and chemical agents came from natural sources. Microorganisms have yielded almost 22,000 natural compounds. The identification of antimicrobial components from endophytes bacteria could help overcome the threat posed by multi-drug resistant strains. The project aims to analyze and identify antimicrobial peptides isolated from entophytic bacteria and their activity against multidrug-resistant Gram-negative bacteria in South Korea. Endophytic Paenibacillus polymyxa. 4G3 isolated from the plant, Gynura procumbery exhibited considerable antimicrobial activity against Methicillin-resistant Staphylococcus aureus, and Escherichia coli. The Rapid Annotations using Subsystems Technology showed that the total size of the draft genome was 5,739,603bp, containing 5178 genes with 45.8% G+C content. Genome annotation using antiSMASH version 6.0.0 was performed, which predicted the most common types of non-ribosomal peptide synthetase (NRPS) and polyketide synthase (PKS). In this study, diethyl aminoethyl cellulose (DEAEC) resin was used as the first step in purifying for unknown peptides, and then the target protein was identified using hydrophilic and hydrophobic solutions, optimal pH, and step-by-step tests for antimicrobial activity. This crude was subjected to C18 chromatography and elution with 0, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100% methanol, respectively. Only the fraction eluted with 20% -60% methanol demonstrated good antimicrobial activity against MDR E. coli. The concentration of the active fragment was measured by the Brad-ford test, and Protein A280 - Thermo Fisher Scientific at the end by examining the SDS PAGE Resolving Gel, 10% Acrylamide and purity were confirmed. Our study showed that, based on the combined results of the analysis and purification. P polymyxa. 4G3 has a high potential exists for producing novel functions of polymyxin E and bacitracin against bacterial pathogens.

Keywords: endophytic bacteria, antimicrobial activity, antimicrobial peptide, whole genome sequencing analysis, multi -drug resistance gram negative bacteria

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Authors: Abu Salim Mustafa

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The comparisons of mycobacterial genomes have identified several Mycobacterium tuberculosis-specific genomic regions that are absent in other mycobacteria and are known as regions of differences. Due to M. tuberculosis-specificity, the peptides encoded by these regions could be useful in the specific diagnosis of tuberculosis. To explore this possibility, overlapping synthetic peptides corresponding to 39 proteins predicted to be encoded by genes present in regions of differences were tested for antibody-reactivity with sera from tuberculosis patients and healthy subjects. The results identified four immunodominant peptides corresponding to four different proteins, with three of the peptides showing significantly stronger antibody reactivity and rate of positivity with sera from tuberculosis patients than healthy subjects. The fourth peptide was recognized equally well by the sera of tuberculosis patients as well as healthy subjects. Predication of antibody epitopes by bioinformatics analyses using ABCpred server predicted multiple linear epitopes in each peptide. Furthermore, peptide sequence analysis for sequence identity using BLAST suggested M. tuberculosis-specificity for the three peptides that had preferential reactivity with sera from tuberculosis patients, but the peptide with equal reactivity with sera of TB patients and healthy subjects showed significant identity with sequences present in nob-tuberculous mycobacteria. The three identified M. tuberculosis-specific immunodominant peptides may be useful in the serological diagnosis of tuberculosis.

Keywords: genomic regions of differences, Mycobacterium tuberculossis, peptides, serodiagnosis

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Authors: Sukhwinder K. Bhullar, M. B. G. Jun

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The developments in biomedical industry have demanded the development of biocompatible, high performance materials to meet higher engineering specifications. The general requirements of such materials are to provide a combination of high stiffness and strength with significant weight savings, resistance to corrosion, chemical resistance, low maintenance, and reduced costs. Auxetic materials which come under the category of smart materials offer huge potential through measured enhancements in mechanical properties. Unique deformation mechanism, providing cushioning on indentation, automatically adjustable with its strength and thickness in response to forces and having memory returns to its neutral state on dissipation of stresses make them good candidate in biomedical industry. As simple extension and compression of tissues is of fundamental importance in biomechanics, therefore, to study the elastic behaviour of auxetic soft tissues implant is targeted in this paper. Therefore development and characterization of auxetic soft tissue implant is studied in this paper. This represents a real life configuration where soft tissue such as meniscus in knee replacement, ligaments and tendons often are taken as transversely isotropic. Further, as composition of alternating polydisperse blocks of soft and stiff segments combined with excellent biocompatibility make polyurethanes one of the most promising synthetic biomaterials. Hence selecting auxetic polyurathylene foam functional characterization is performed and compared with conventional polyurathylene foam.

Keywords: auxetic materials, deformation mechanism, enhanced mechanical properties, soft tissues

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Authors: Athini Ntloko

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Mycobacterium bovis and other species of Mycobacterium tuberculosis complex (MTBC) can result to a zoonotic infection known as Bovine tuberculosis (bTB). MTBC has members that may contaminate an extensive range of hosts, including wildlife. Diverse wild species are known to cause disease in domestic livestock and are acknowledged as TB reservoirs. It has been a main study worldwide to deliberate on bTB risk factors as a result and some studies focused on particular parts of risk factors such as wildlife and herd management. The significance of the study was to determine the incidence of Mycobacterium tuberculosis complex that is associated with soil, hayfeed and water. Questionnaires were administered to thirty (30) smallholding farm owners in the two villages (kwaMasele and Qungqwala) and three (3) three commercial farms (Fort Hare dairy farm, Middledrift dairy farm and Seven star dairy farm). Detection of M. tuberculosis complex was achieved by Polymerase Chain Reaction using primers for IS6110; whereas a genotypic drug resistance mutation was detected using Genotype MTBDRplus assays. Nine percent (9%) of respondents had more than 40 cows in their herd, while 60% reported between 10 and 20 cows in their herd. Relationship between farm size and vaccination for TB differed from forty one percent (41%) being the highest to the least five percent (5%). The highest number of respondents who knew about relationship between TB cases and cattle location was ninety one percent (91%). Approximately fifty one percent (51%) of respondents had knowledge about wild life access to the farms. Relationship between import of cattle and farm size ranged from nine percent (9%) to thirty five percent (35%). Cattle sickness in relation to farm size differed from forty three (43%) being the highest to the least three percent (3%); while thirty three percent (33%) of respondents had knowledge about health management. Respondents with knowledge about the occurrence of TB infections in farms were forty-eight percent (48%). The frequency of DNA isolation from samples ranged from the highest forty-five percent (45%) from water to the least twenty two percent (22%) from soil. Fort Hare dairy farm had the highest number of positive samples, forty four percent (44%) from water samples; whereas Middledrift dairy farm had the lowest positive from water, seventeen percent (17%). Twelve (22%) out of 55 isolates showed resistance to INH and RIF that is, multi-drug resistance (MDR) and nine percent (9%) were sensitive to either INH or RIF. The mutations at rpoB gene differed from 58% being the highest to the least (23%). Fifty seven percent (57%) of samples showed a S315T1 mutation while only 14% possessed a S531L in the katG gene. The highest inhA mutations were detected in T8A (80 %) and the least was observed in A16G (17%). The results of this study reveal that risk factors for bTB in cattle and dairy farm workers are a serious issue abound in the Eastern Cape of South Africa; with the possibility of widespread dissemination of multidrug resistant determinants in MTBC from the environment.

Keywords: hayfeed, isoniazid, multi-drug resistance, mycobacterium tuberculosis complex, polymerase chain reaction, rifampicin, soil, water

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Authors: Sepehr Lajevardi Esfahani, Shohre Rouhani, Zahra Ranjbar

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Graphene has gained much attention owing to its unique optical and electrical properties. Charge carriers in graphene sheets (GS) carry out a linear dispersion relation near the Fermi energy and behave as massless Dirac fermions resulting in unusual attributes such as the quantum Hall effect and ambipolar electric field effect. It also exhibits nondispersive transport characteristics with an extremely high electron mobility (15000 cm²/(Vs)) at room temperature. Recently, several progresses have been achieved in the fabrication of single- or multilayer GS for functional device applications in the fields of optoelectronic such as field-effect transistors ultrasensitive sensors and organic photovoltaic cells. In addition to device applications, graphene also can serve as reinforcement to enhance mechanical, thermal, or electrical properties of composite materials. Electrophoretic deposition (EPD) is an attractive method for development of various coatings and films. It readily applied to any powdered solid that forms a stable suspension. The deposition parameters were controlled in various thicknesses. In this study, the graphene electrodeposition conditions were optimized. The results were obtained from SEM, Ohm resistance measuring technique and AFM characteristic tests. The minimum sheet resistance of electrodeposited reduced graphene oxide layers is achieved at conditions of 2 V in 10 s and it is annealed at 200 °C for 1 minute.

Keywords: electrophoretic deposition (EPD), graphene oxide (GO), electrical conductivity, electro-optical devices

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Authors: M. Murmu, Govardhan, J. Satya Eswari

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Concrete is the most common and widely used building material. Concrete is basically made of aggregates, both fine and coarse, glued by a cement paste which is made of cement and water. Each one of these constituents of concrete has a negative environmental impact and gives rise to different sustainability issues. The current concrete construction practice is unsustainable because, not only it consumes enormous quantities of stones, sand, and drinking water, but also one billion tons a year of cement, which is not an environment friendly material. Preventing the reduction of natural resources and enhancing the usage of waste materials has become a challenge to the scientist and engineers. A number of studies have been conducted concerning the protection of natural resources, prevention of environmental pollution and contribution to the economy by using this waste material. This paper outlines the influence of Ground Granulated Blast furnace Slag (GGBS) as partial replacement of fine aggregate on mechanical properties of concrete. The strength of concrete is determined having OPC binder, replaced the fine aggregate with15%, 30%, 45% respectively. For this purpose, characteristics concrete mix of M25 with partial replacement of cement with GGBS is used and the strength of concrete cubes and cylinder have determined. The strength of concrete specimens has been compared with the reference specimen. Also X-ray diffraction (XRD) and scanning electron microscope (SEM) tests have been performed to examine the hydration products and the microstructure of the tested specimens. A correlation has been established between the developmental strength concrete with and without GGBS through analysis of hydration products and the microstructure.

Keywords: GGBS, sand, concrete, workability

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Authors: Kai-Fen Tu, Jenn-Wen Huang, Yao-Tung Lin

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Cucumber is a major economic crop in the world. The global production of cucumber in 2017 was more than 71 million tonnes. Nonetheless, downy mildew, caused by Pseudoperonospora cubensis, is a devastating and common disease on cucumber in around 80 countries and causes severe economic losses. The long-term usage of fungicide also leads to the occurrence of fungicide resistance and decreases host resistance. In this study, six types of oil (neem oil, moringa oil, soybean oil, cinnamon oil, clove oil, and camellia oil) were selected to synthesize micro/nano-sized emulsions, and the disease control efficacy of micro/nano-sized emulsions were evaluated. Moreover, oil concentrations (0.125% - 1%) and droplet size of emulsion were studied. Results showed cinnamon-type emulsion had the best efficacy among these oils. The disease control efficacy of these emulsions increased as the oil concentration increased. Both disease incidence and disease severity were measured by detached leaf and pot experiment, respectively. For the droplet size effect, results showed that the 114 nm of droplet size synthesized by 0.25% cinnamon oil emulsion had the lowest disease incidence (6.67%) and lowest disease severity (33.33%). The release of zoospore was inhibited (5.33%), and the sporangia germination was damaged. These results suggest that cinnamon oil emulsion will be a valuable and environmentally friendly alternative to control cucumber downy mildew. The economic loss caused by plant disease could also be reduced.

Keywords: downy mildew, emulsion, oil droplet size, plant protectant

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Authors: Ayad Salih Sabbar, Amin Chegenizadeh, Hamid Nikraz

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Utilizing waste materials in civil engineering applications has a positive influence on the environment by reducing carbon dioxide emissions and issues associated with waste disposal. Granulated blast furnace slag (GBFS) is a by-product of the iron and steel industry, with millions of tons of slag being annually produced worldwide. Slag has been widely used in structural engineering and for stabilizing clay soils; however, studies on the effect of slag on sandy soils are scarce. This article investigates the effect of slag content on shear strength parameters through direct shear tests and unconsolidated undrained triaxial tests on mixtures of Perth sand and slag. For this purpose, sand-slag mixtures, with slag contents of 2%, 4%, and 6% by weight of samples, were tested with direct shear tests under three normal stress values, namely 100 kPa, 150 kPa, and 200 kPa. Unconsolidated undrained triaxial tests were performed under a single confining pressure of 100 kPa and relative density of 80%. The internal friction angles and shear stresses of the mixtures were determined via the direct shear tests, demonstrating that shear stresses increased with increasing normal stress and the internal friction angles and cohesion increased with increasing slag. There were no significant differences in shear stresses parameters when slag content rose from 4% to 6%. The unconsolidated undrained triaxial tests demonstrated that shear strength increased with increasing slag content.

Keywords: direct shear, shear strength, slag, UU test

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Authors: Begüm Terzi, Özlem Ateş Sönmezoğlu, Ahmet Yildirim

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Drought is the most important factor that limiting the production and productivity of wheat in the world. The yield of wheat, which is one of the most important crop in the world, reduced depend on drought. Researches to minimize effects of drought are one of the most important about breeding of drought resistant varieties. In recent years, benefiting from the drought resistance wild species and rapid advances in molecular biology studies, researches about drought have been accelerated and number of studies were made on molecular plant breeding which included the molecular mechanisms related to drought resistance. The aim of the present study was characterization of some bread wheat lines for drought tolerance which commonly cultivated in different location of Turkey. In this study, registered 9 bread wheat varieties which on the physiological tests about drought tolerance and 10 bread wheat line has been developed by Transitional Zone Agricultural Research Institute were used. SSR, STS, RAPD and SNP markers that associated with drought tolerance were used. The polymorphisms of the markers were determined by screening of two control varieties. For these purpose 40 molecular markers were used and 12 markers of them were polymorphic among the drought tolerance and the drought sensitive varieties. Control varieties were screened using polymorphic markers. All the DNAs on the genotypes will be searched for the presence of QTLs mapped to different chromosomes. Result of the research, the studied genotypes will be grouped according to drought tolerance and will be detected drought tolerance varieties by molecular markers. In addition, the results will be compared also with physiological tests. The drought tolerant wheat genotypes may be used in breeding studies related to drought stress.

Keywords: bread wheat, drought, molecular marker, Triticum aestivum

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Authors: Arash Dara, Mahsa Mokhtari, Nafiseh Zamindar

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The aim of this study was to determine the effect of thermal resistance, temperature, voltage, and pH changes in an ohmic heating system on reducing the logarithmic number of Byssochlamys fulva species (PTCC 5062) in tomato juice water and to investigate the quantitative properties of tomato juice in the ohmic heating pasteurization system. The percentage of thermal degradation by ohmic heating was determined in tomato juice for the kinetics of Byssochlamys fulva in ohmic chamber at the temperatures of 88, 93, and 98°C, with two voltages of 30 and 40 volts and two pH levels of 3.5 and 4.5; this was done using Weibull frequency distribution model. Three different parameters (pH = 3.5, two voltages of 30 and 40, at three temperatures 88, 93, and 98) and (pH = 4.5, two voltages 30 and 40, at three temperatures 88, 93, and 98) in three replications were considered in the ohmic system. Heating time for the temperature of 88°C was 20 minutes once every 2 minutes, while for the temperature of 93°C, it was 10 minutes once every 1 minute. At the temperature of 98°C, the first time was 0.5 minutes, and for other times, sampling was done every 1 minute. In each condition, the qualitative characteristics, including acidity, Brix, and pH, were measured before and after the ohmic process in the tomato juice. This study demonstrates that the differences in pH and voltage due to different temperatures in the ohmic process can greatly affect the inactivation of Byssochlamys fulva fungus and the qualitative characteristics of the tomato juice. This is the first study using the Weibull frequency method to model the inactivation of Byssochlamys fulva in tomato juice. Variation in parameters such as temperature, voltage, and pH can prevent the presence of Byssochlamys fulva in the pasteurized juices.

Keywords: pasteurization, ohmic heating process, Byssochlamys fulva, tomato juice, heat resistance, voltage, pH

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Authors: David Oluwole Moses, Odeyemi Adebowale Toba, Olawale Adetunji Kola

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Candida auris, an emerging fungus, has been reported in more than 30 countries around the world since its first detection in 2009. Due to its several virulence factors, resistance to antifungals, and persistence in hospital settings, Candida auris has been reported to cause treatment-failure infections. This study was therefore carried out to determine the incidence of Candida auris in a tertiary hospital in Ekiti State, Nigeria. In this study, a total of 115 samples were screened for Candida species using cultural and molecular methods. The carriage of virulence factors and antifungal resistance among C. auris was detected using standard microbiological methods. Candida species isolated from the samples were 15 (30.0%) in clinical samples and 22 (33.85%) in hospital equipment screened. Non-albicans Candida accounted for 3 (20%) and 8 (36.36%) among the isolates from the clinical samples and equipment, respectively. Only five of the non-albicans Candida isolates were C. auris. All the isolates produced biofilm, gelatinase, and hemolysin, while none produced germ tubes. Two of the isolates were resistant to all the antifungals tested. Also, all the isolates were resistant to fluconazole and itraconazole. Nystatin appeared to be the most effective among the tested antifungals. The isolation of Candida auris is being reported for the second time in Nigeria, further confirming that the fungus has spread beyond Lagos and Ibadan, where it was first reported. The extent of the spread of the nosocomial fungus needed to be further investigated and curtailed in Nigeria before its outbreak in healthcare facilities.

Keywords: candida auris, virulence factors, antifungals, pathogen, hospital, infection

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Authors: Palanisamy Samyraj, Sriram Yogesh, Kishore Kumar, Vaishak Cibi

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The project is about design and analysis of crankshaft using Al-Al2O3 composite material. The project is mainly concentrated across two areas one is to design and analyze the composite material, and the other is to work on the practical model. Growing competition and the growing concern for the environment has forced the automobile manufactures to meet conflicting demands such as increased power and performance, lower fuel consumption, lower pollution emission and decrease noise and vibration. Metal matrix composites offer good properties for a number of automotive components. The work reports on studies on Al-Al2O3 as the possible alternative material for a crank shaft. These material have been considered for use in various components in engines due to the high amount of strength to weight ratio. These materials are significantly taken into account for their light weight, high strength, high specific modulus, low co-efficient of thermal expansion, good air resistance properties. In addition high specific stiffness, superior high temperature, mechanical properties and oxidation resistance of Al2O3 have developed some advanced materials that are Al-Al2O3 composites. Crankshafts are used in automobile industries. Crankshaft is connected to the connecting rod for the movement of the piston which is subjected to high stresses which cause the wear of the crankshaft. Hence using composite material in crankshaft gives good fuel efficiency, low manufacturing cost, less weight.

Keywords: metal matrix composites, Al-Al2O3, high specific modulus, strength to weight ratio

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Authors: N. M. Aborehab, M. Helmy, N. E. Waly

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Resistin was identified as an adipocyte hormone that participates in regulation of glucose metabolism. Elevated levels of Resistin are postulated to cause insulin resistance. This may link obesity, and increased fat mass to type II diabetes and insulin resistance. We hypothesized that tomato and broccoli extract treatment regulates glucose homeostasis via modulation of resistin levels in high fat diet induced obesity rats (HFD). 63 male albino rats were divided into 8 groups as follows: control, HFD, stop fat diet (SD), Tomato 200 mg/kg (T200), Tomato 400mg/kg (T400), Broccoli 200 mg/kg (B200), Broccoli 400 mg/kg (B400), Chromax (CX). Treatment continued for 1 month. Serum levels of resistin, leptin, adiponectin, glucose and insulin were measured using ELISA, and spectrophotometry. Serum level of resistin was significantly reduced in T 200, T 400, B 200, B 400 and CX groups to: 4.13 ± 0.22 ng/ml, 1.51 ± 0.04 ng/ml, 4.13 ± 0.22 ng/ml, 2.32 ± 0.15 ng/ml and 1.37 ± 0.03 ng/ml respectively compared to HFD group and SD group (P value < 0.0001). Non-significant difference was found between T 400, B 400 and CX groups. Mean serum level of leptin was significantly reduced in T 400 (22.7 ± 0.84 Pg/ml) group compared to B 400 (41 ± 2.45 Pg/ml) and CX groups (45.7 ± 2.91 Pg/ml), P value < 0.001.The mean serum level of adiponectin was significantly increased in T 400 group (131 ± 3.84 Pg/ml) compared to CX group (112 ± 4.77 Pg/ml), P value was < 0.01. Our results demonstrate that tomato and broccoli extract treatment regulates glucose homeostasis via reduction of serum resistin and may be a useful non-pharmacological therapy for obesity. Further studies are required to assess the potential use of these extract as a treatment for type II diabetes and obesity.

Keywords: broccoli, obesity, resistin, tomato

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Authors: Supreet Singh, Manpreet Kaur, Manoj Kumar

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High temperature corrosion is an imperative material degradation method experienced in thermal power plants and other energy generation sectors. Metallic materials such as ferritic steels have special properties such as easy fabrication and machinibilty, low cost, but a serious drawback of these materials is the worsening in properties initiating from the interaction with the environments. The metallic materials do not endure higher temperatures for extensive period of time because of their poor corrosion resistance. Friction Stir Processing (FSP), has emerged as the potent surface modification means and control of microstructure in thermo mechanically heat affecting zones of various metal alloys. In the current research work, FSP was done on the boiler tube of SA 210 Grade A1 material which is regularly used by thermal power plants. The strengthening of SA210 Grade A1 boiler steel through microstructural refinement by Friction Stir Processing (FSP) and analyze the effect of the same on high temperature corrosion behavior. The high temperature corrosion performance of the unprocessed and the FSPed specimens were evaluated in the laboratory using molten salt environment of Na₂SO₄-82%Fe₂(SO₄). The unprocessed and FSPed low carbon steel Gr A1 evaluation was done in terms of microstructure, corrosion resistance, mechanical properties like hardness- tensile. The in-depth characterization was done by EBSD, SEM/EDS and X-ray mapping analyses with an aim to propose the mechanism behind high temperature corrosion behavior of the FSPed steel.

Keywords: boiler steel, characterization, corrosion, EBSD/SEM/EDS/XRD, friction stir processing

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Authors: B. Oji, O. Olaniran

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The prospect of improving the corrosion property of Al 6063 alloy based hybrid composites reinforced with cassava peel ash (CPA) and silicon carbide (SiC) is the target of this research. It seeks to determine the viability of using locally sourced material (CPA) as a complimentary reinforcement for SiC to produce low cost high performance aluminum matrix composite. The CPA was mixed with the SiC in the ratios 0:1, 1:3, 1:1, 3:1 and 1:0 for 8 wt % reinforcement in the produced composites by double stir-casting method. The microstructures of the composites were studied before and after corrosion using the scanning electron microscopy which reveals the matrix (dark region) and eutectic phase (lamellar region). The corrosion rate was studied in accordance with ASTM G59-97 (2014) using an AutoLab potentiostat (Versa STAT 400) with versaSTUDIO electrochemical software which analyses the results obtained. The result showed that Al 6063 alloy exhibited good corrosion resistance in 0.3M H₂SO₄ and 3.5 wt. % NaCl solutions with sample C containing the 25% wt CPA showing the highest resistance to corrosion with corrosion rate of 0.0046 mmpy as compared to the control sample which has a value of 13.233 mmpy. Sample B, D, E, and F also showed a corrosion rate of 3.9502, 2.6903, 2.1223, and 5.7344 mmpy which indicated a better corrosion rate than the control in the acidic environment. The corrosion rate in the saline medium shows that sample E with 75% wt CPA has the lowest corrosion rate of 0.0422 mmpy as compared to the control sample with 0.0873 mmpy corrosion rate.

Keywords: Al-Mg-Si alloy, AutoLab potentiostat, Cassava Peel Ash, CPA, hybrid composite, stir-cast method

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Authors: Ali Alahmari

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Urban drainage in Saudi Arabia is an increasingly challenging issue due to factors such as climate change and rapid urban expansion. The existing infrastructure, based on traditional drainage systems, is not always able to cope with the increased precipitation, sometimes leading to rainwater runoff and floods causing disturbances and damage to property. Therefore, there is a need to find new ways of managing drainage, such as Sustainable Urban Drainage Systems (SUDS). The research has highlighted the main driving forces behind the need for change, revealed by the participants, to the need to adopt new ideas and approaches for urban drainage. However, while moving towards this, certain factors that may hinder the aim of using the experiences of other countries and taking advantage of innovative solutions. The research illustrates an initial conceptual model for these factors emerging from the analysis. It identifies some of the fundamental issues affecting the resistance to change towards the adoption of the concept of sustainability in Saudi Arabia, with Riyadh city as a case study. This was by using a qualitative approach, whereby, through two phases of fieldwork during 2013 and 2014, twenty-six semi-structured interviews were conducted with a number of representative officials and professionals from key government departments and organisations related to urban drainage management. Grounded Theory approach was followed to analyse the qualitative data obtained. Resistance to change was classified to: firstly: individual inertia (e.g. familiarity with the conventional solutions and approaches, lack of awareness, and considering sustainability as a marginal matter in urban planning). This resulted in not paying the desired attention, and impact on planning and setting priorities for development. Secondly: institutionalised inertia (e.g. lack of technical and design specifications for other unconventional drainage solutions, lack of consideration by decision makers in other disciplines such as contributions from environmental and geographical studies, and routine work and bureaucracy). This contributes to the weakness of decision-making, weakness in the role of research, and a lack of human resources. It seems that attitudes towards change may have reduced the ability to move forward towards sustainable development, in addition to contributing towards difficulties in some aspects of the decision-making process. Thus, the chapter provides insights into the current situation in Saudi Arabia and contributes to understanding the decisions that are made regarding change.

Keywords: climate change, new knowledge and approaches, resistance to change, Saudi Arabia, SUDS, urban drainage, urban expansion

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Authors: Thi Thu Van Nguyen

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In South Korea, Confucianism has not only played a crucial position in Korean traditional culture but also deeply rooted in people’s mind. Confucianism bears a special emphasis on the traditional family pattern characterized by paternalism. Therefore, non-paternity families are barely recognized and unwed mothers are faced with numerous prejudices in their life. Prejudice to unwed mothers in Korea is believed to stem from social discourses against lone motherhood which is the way how people look and talk about unwed mothers and from the early time these social discourses have big impacts on their daily lives. However, after the 1990s, along with the rapid transformation of family pattern and support from social welfare organizations, unwed mothers have gradually got to escape from the social prejudice then established themselves as a new family form. This study is aimed at researching social discourses on lone motherhood in Korea and the process of resistance, adaptation and negotiation of unwed mothers in three different stages: the antenatal, postnatal stages and social inclusion. The anthropological method is employed. Twenty single young mothers of the Korean Unwed Mothers Families' Association were engaged in the author’s detailed interviews. The study’s frame analysis is based on the theoretical framework on social discourses on lone motherhood by Simon Duncan and Rosalind Edwards (1999). This study is an effort to comprehend and investigate the difficulties experienced by unwed mothers living in negative social discourses and the way they overcome the difficulties.

Keywords: unwed mothers, gender, social discourses, social prejudice, Confucianism

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Authors: Marcus Klein, Martina GrießBach, Richard Kupke

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The current advances in the research and manufacturing of large area graphene layers are promising towards the introduction of this exciting material in the display industry and other applications that benefit from excellent electrical and optical characteristics. New production technologies in the fabrication of flexible displays, touch screens or printed electronics apply graphene layers on non-metal substrates and bring new challenges to the required metrology. Traditional measurement concepts of layer thickness, sheet resistance, and layer uniformity, are difficult to apply to graphene production processes and are often harmful to the product layer. New non-contact sensor concepts are required to adapt to the challenges and even the foreseeable inline production of large area graphene. Dedicated non-contact measurement sensors are a pioneering method to leverage these issues in a large variety of applications, while significantly lowering the costs of development and process setup. Transferred and printed graphene layers can be characterized with high accuracy in a huge measurement range using a very high resolution. Large area graphene mappings are applied for process optimization and for efficient quality control for transfer, doping, annealing and stacking processes. Examples of doped, defected and excellent Graphene are presented as quality images and implications for manufacturers are explained.

Keywords: graphene, doping and defect testing, non-contact sheet resistance measurement, inline metrology

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Authors: Ki-Ho Nam, Haksoo Han

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Tetrapod zinc oxide whiskers (TZnO-Ws) were successfully synthesized by a thermal oxidation method. A series of transparent polyimide (PI)/TZnO-W composites were successfully synthesized via a solution-blending method. The structural and morphological features of TZnO-Ws and PI/TZnO-W composites were characterized by Fourier transform infrared spectroscopy (FT-IR), wide-angle X-Ray diffraction (WAXD), and field emission scanning electron microscope (FE-SEM). Dynamic stress behaviors were investigated in-situ during thermal imidization of the soft-baked PI/TZnO-W composite precursor and thermally cured composite films using a thin film stress analyzer (TFSA) by wafer bending technique. The PI/TZnO-W composite films exhibited an optical transparency greater than 80% at 550 nm (≤ 0.5 wt% TZnO-W content), a low coefficient of thermal expansion (CTE), and enhanced glass transition temperature. However, the thermal decomposition temperature decreased as the TZnO-W content increased. The water diffusion coefficient and water uptake of the PI/TZNO-W composite films were obtained by best fits to a Fickian diffusion model. The water resistance capacity of PI was greatly enhanced and moisture diffusion in the pure PI was retarded by incorporating the TZnO-W. The PI composite films based on TZNO-W resultantly may have potential applications in optoelectronic manufacturing processes as a flexible transparent substrate.

Keywords: polyimide (PI), tetrapod ZnO whisker (TZnO-W), transparent, dynamic stress behavior, water resistance

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Authors: Elizabeth Starzycka-Korbas, Michal Starzycki, Wojciech Rybinski, Mirosława Dabert

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For a few years, the populations of pathogenic fungi occurring in winter oilseed rape in Malyszyn were analyzed. Brassica napus L. in Poland and in the world is a source of energy for both the men (oil), and animals, as post-extraction middling, as well as a motor fuel (oil, biofuel) therefore studies of this type are very important. The species composition of pathogenic fungi can be an indicator of seed yield. The occurrence of oilseed rape pathogens during several years were analyzed using the sequencing method DNA ITS. The results were compared in the gene bank using the program NCBI / BLAST. In field conditions before harvest of oilseed rape presence of pathogens infesting B. napus has been assessed. For example, in 2015, 150 samples have been isolated and applied to PDA medium for the identification of belonging species. From all population has been selected mycelium of 83 isolates which were sequenced. Others (67 isolates) were pathogenic fungi of the genus Alternaria which are easily to recognize. The population of pathogenic species on oilseed rape have been identified after analyzing the DNA ITS and include: Leptosphaeria sp. 38 (L. maculans 25, L. biglobosa 13), Alternaria sp. 29, Fusarium sp. 3, Sclerotinia sclerotiorum 7, heterogeneous 6, total of 83 isolates. The genus Alternaria sp. fungi wear the largest share of B. napus pathogens in particular years. Another dangerous species for oilseed rape was Leptosphaeria sp. Populations of pathogens in each year were different. The number of pathogens occurring in the field and their composition is very important for breeders and farmers because of the possible selection of the most resistant genotypes for sowing in the next growing season.

Keywords: B. napus, DNA ITS Sequencing, pathogenic fungi, population

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Authors: Sudheer Kumar Gundati, Umasankar Patro

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Carbon nanotube (CNT) – polymer composites have been extensively studied due to their exceptional electrical and mechanical properties. In the present study, poly(vinylidene fluoride) (PVDF) – multi-walled CNT composites were prepared by melt-blending technique using pristine (ufCNT) and a modified dilute nitric acid-treated CNTs (fCNT). Due to this dilute acid-treatment, the fCNTs were found to show significantly improved dispersion and retained their electrical property. The fCNT showed an electrical percolation threshold (PT) of 0.15 wt% in the PVDF matrix as against 0.35 wt% for ufCNT. The composites were made into films of thickness ~0.3 mm by compression-molding and the resulting composite films were subjected to various property evaluations. It was found that the water contact angle (WCA) of the films increased with CNT weight content in composites and the composite film surface became hydrophobic (e.g., WCA ~104° for 4 wt% ufCNT and 111.5° for 0.5 wt% fCNT composites) in nature; while the neat PVDF film showed hydrophilic behavior (WCA ~68°). Significant enhancements in the mechanical properties were observed upon CNT incorporation and there is a progressive increase in the tensile strength and modulus with increase in CNT weight fraction in composites. The composite films were tested for strain-sensing applications. For this, a simple and non-destructive method was developed to demonstrate the strain-sensing properties of the composites films. In this method, the change in electrical resistance was measured using a digital multimeter by applying bending strain by oscillation. It was found that by applying dynamic bending strain, there is a systematic change in resistance and the films showed piezo-resistive behavior. Due to the high flexibility of these composite films, the change in resistance was reversible and found to be marginally affected, when large number of tests were performed using a single specimen. It is interesting to note that the composites with CNT content notwithstanding their type near the percolation threshold (PT) showed better strain-sensing properties as compared to the composites with CNT contents well-above the PT. On account of the excellent combination of the various properties, the composite films offer a great promise as strain-sensors for structural health-monitoring.

Keywords: carbon nanotubes, electrical percolation threshold, mechanical properties, poly(vinylidene fluoride), strain-sensor, water contact angle

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Authors: Senthil Rajan Dharmalingam, Shamala Nadaraju, Srinivasan Ramamurthy

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Doxorubicin is the most widely used anticancer drugs in chemotherapy treatment. However, problems related to the development of multidrug resistance (MDR) and acute cardiotoxicity have led researchers to investigate alternative forms of administering doxorubicin for cancer therapy. Several methods have been attempted to overcome MDR, including the co-administration of a chemosensitizer inhibiting the efflux caused by ATP binding cassette transporters with anticancer drugs, and the bypass of the efflux mechanism. Co encapsulation of doxorubicin (Dox) and cyclosporine A (CSA) into poly (DL-lactide-co-glycolide) nanoparticles was emulsification-solvent evaporation method using polyvinyl alcohol as emulsion stabilizers. The Dox-CSA loaded nanoparticles were evaluated for particle size, zeta potential and PDI by light scattering analysis and thermal characterizations by differential scanning calorimetry (DSC). Loading efficiency (LE %) and in-vitro dissolution samples were evaluated by developed and validated HPLC method. The optimum particle size obtained is 298.6.8±39.4 nm and polydispersity index (PDI) is 0.098±0.092. Zeta potential is found to be -29.9±4.23. Optimum pH to increase Dox LE% was found 7.1 which gave 42.5% and 58.9% increase of LE% for pH 6.6 and pH 8.6 compared respectively. LE% achieved for Dox is 0.07±0.01 % and CSA is 0.09±0.03%. Increased volume of PVA and weight of PLGA shows increase in size of nanoparticles. DSC thermograms showed shift in the melting peak for the nanoparticles compared to Dox and CSA indicating encapsulation of drugs. In conclusion, these preliminary studies showed the feasibility of PLGA nanoparticles to entrap Dox and CSA and require future in-vivo studies to be performed to establish its potential.

Keywords: doxorubicin, cyclosporine, PLGA, nanoparticles

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Authors: Abdul Walusansa

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In this paper, paper notes and coins were collected from general public in Kampala City where ready-to-eat food can be served, in order to survey for bacterial contamination. The total bacterial number and potentially pathogenic organisms loading on currency were tested. All isolated potential pathogens were also tested for antibiotic resistance against four most commonly prescribed antibiotics. 1. The bacterial counts on one hundred paper notes sample were ranging between 6～10918/cm cm-2,the median was 141/ cm-2, according to the data it was much higher than credit cards and Australian notes which were made of polymer. The bacterial counts on sixty coin samples were ranging between 2～380/cm-2, much less than paper notes. 2. Coliform (65.6%), E. coli (45.9%), S. aureus (41.7%), B. cereus (67.7%), Salmonella (19.8%) were isolated on one hundred paper notes. Coliform (22.4%), E. coli (5.2%), S. aureus (24.1%), B. cereus (34.5%), Salmonella (10.3%) were isolated from sixty coin samples. These results suggested a high rate of potential pathogens contamination of paper notes than coins. 3. Antibiotic resistances are commonly in most of the pathogens isolated on currency. Ampicillin resistance was found in 60%of Staphylococcus aureus isolated on currency, as well as 76.6% of E. coil and 40% of Salmonella. Erythromycin resistance was detected in 56.6% of S. aureus and in 80.0% of E. coli. All the pathogens isolated were sensitive to Norfloxacin, Salmonella and S. aureus also sensitive to Cefaclor. In this paper, we also studied the antimicrobial capability of metal coins, coins collected from different countries were tested for the ability to inhibit the growth of E. sakazakii, S. aureus, E. coli, L. monocytogenes and S. typhimurium. 1) E. sakazakii appeared very sensitive to metal coins, the second is S. aureus, but E. coli, L. monocytogenes and S. typhimurium are more resistant to these metal coin samples. 2) Coins made of Nickel-brass alloy and Copper-nickel alloy showed a better effect in anti-microbe than other metal coins, especially the ability to inhibited the growth of E. sakazakii and S. aureus, all the inhibition zones produced on nutrient agar are more than 20.6 mm. Aluminium-bronze alloy revealed weak anti-microbe activity to S. aureus and no effect to kill other pathogens. Coins made of stainless steel also can’t resist bacteria growth. 3) Surprisingly, one cent coins of USA which were made of 97.5% Zinc and 2.5% Cu showed a significant antimicrobial capability, the average inhibition zone of these five pathogens is 45.5 mm.

Keywords: antibiotic sensitivity, bacteria, currency, coins, parasites

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Authors: Jain Jyoti, Jain Shorab, Sinha Shishir

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In the field of material engineering, composites are in great concern for their nonbiodegradability and their cost. In order to reduce its cost and weight, plant derived fibers witnessed miraculous triumph. Plant fibers can be of different types like seed fibers, blast fibers, leaf fibers, etc. Composites can be reinforced with exclusively one type of natural fiber or also can be combined with two or more different types of natural or synthetic fibers to boost up their specific properties. Among all natural fibers, wheat straw, bagasse, kenaf, pineapple leaf, banana, coir, ramie, flax, etc. pineapple leaf fibers have very good mechanical properties. Being hydrophilic in nature, pineapple leaf fibers have very less affinity towards all types of polymer matrixes like HDPE, LDPE, PET, epoxy, etc. Surface treatments like alkaline treatment in different concentrations were conducted to improve its adhesion and compatibility towards hydrophobic polymer matrix i.e. epoxy resin. Pineapple leaf fiber epoxy composites have been prepared using hand layup method. Effect of fiber loading and surface treatments have been studied for different mechanical properties i.e. tensile strength, flexural strength and impact properties of pineapple leaf fiber composites. Analysis of fiber morphology has also been studied using FTIR, XRD. Scanning electron microscopy has also been used to study and compare the morphology of untreated and treated fibers. Also, the fracture surface has been reviewed comparing the reported literature of other eminent researchers of this field.

Keywords: composite, mechanical, natural fiber, pineapple leaf fiber

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Authors: Sibusiso Trevor Tshabalala, Samuel Lubbe, Vince Vuledzani Ndou

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Dependency on chemicals has had many disadvantages in pest management control strategies. Such genetic rodenticide resistance and secondary exposure risk are what is currently being experienced. Emphasis on integrated pest management suggests that to control future pests, early intervention and economic threshold development are key starting points in crop production. The significance of this research project is to help establish a relationship between Giant African Land Snail (Achatina Fulica) solution extract, its shell chemical properties, and farmer’s perceptions of biological control in eThekwini Municipality Agri-hubs. A mixed design approach to collecting data will be explored using a trial layout in the field and through interviews. The experimental area will be explored using a split-plot design that will be replicated and arranged in a randomised complete block design. The split-plot will have 0, 10, 20 and 30 liters of water to one liter of snail solution extract. Plots were 50 m² each with a spacing of 12 m between each plot and a plant spacing of 0.5 m (inter-row) ‘and 0.5 m (intra-row). Trials will be irrigated using sprinkler irrigation, with objective two being added to the mix every 4-5 days. The expected outcome will be improved soil fertility and micro-organisms population proliferation.

Keywords: giant african land snail, integrated pest management, photosynthesis, genetic rodenticide resistance, control future pests, shell chemical properties

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Authors: Eun-Young Kwon, Myung-Sook Choi, Su-Jung Cho, Ji-Young Choi, So Young Kim, Youngji Han

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Overweight and obesity have been linked to a low-grade chronic inflammatory response and an increased risk of developing metabolic syndrome including insulin resistance, type 2 diabetes mellitus and certain types of cancers. Luteolin is a dietary flavonoid with anti-inflammatory, anti-oxidant, anti-cancer and anti-diabetic properties. However, little is known about the detailed mechanism associated with the effect of luteolin on inflammation-related obesity and its complications. The aim of the present study was to reveal the anti-diabetic effect of luteolin in diet-induced obesity mice using “transcriptomics” tool. Thirty-nine male C57BL/6J mice (4-week-old) were randomly divided into 3 groups and were fed normal diet, high-fat diet (HFD, 20% fat) and HFD+0.005% (w/w) luteolin for 16 weeks. Luteolin improved insulin resistance, as measured by HOMA-IR and glucose tolerance, along with preservation action of pancreatic β-cells, compared to the HFD group. Luteoiln was significantly decreased the levels of leptin and ghrelin that play a pivotal role in energy balance, and the macrophage low-grade inflammation marker sCD163 (soluble Cd antigen 163) in plasma. Activities of hepatic anti-oxidant enzymes (catalase and glutathione peroxidase) were increased, while the levels of plasma transaminase (GOT and GPT) and oxidative damage markers (hepatic mitochondria H2O2 and TBARS) were markedly decreased by luteolin supplementation. In addition, luteolin increased oxidative capacity and fatty acid utilization by presenting decrease in enzyme activities of citrate synthase, cytochrome C oxidase and β-hydroxyacyl CoA dehydrogenase and UCP3 gene expression compared to high-fat diet. Moreover, our microarray results of muscle also revealed down-regulated gene expressions associated with TCA cycle by HFD were reversed to normal level by luteolin treatment. Taken together, our results indicate that luteolin is one of bioactive components for improving insulin resistance by increasing oxidative capacity, modulating anti-oxidant metabolism and suppressing inflammatory signaling cascades in diet-induced obese mice. These results provide possible therapeutic targets for prevention and treatment of diet-induced obesity and its complications.

Keywords: anti-oxidant metabolism, diabetes, luteolin, oxidative capacity

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Authors: Wojciech J. Nowak, Natalia Maciaszek, Marcin Drajewicz

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A constant requirement to reduce greenhouse gas emissions in combination with the desire to increase gas turbine efficiency results in a continuous trend to increase the operating temperature of gas turbines. An increase in operating temperature will result in lower fuel consumption, and a higher combustion temperature will result in lower pollution release. Moreover, there is a strong trend for hydrogen to be used as an alternative and clean fuel. However, using hydrogen or hydrogen-rich fuel results in a higher combustion temperature, as well as an increase in the water vapor content in the exhaust gases. Commonly used Ni-base alloys have their limits. Moreover, the presence of water vapor worsens the oxidation behavior of Ni-based alloys at a high temperature. Therefore, a new brand of materials is demanded to be used in gas turbines operated with hydrogen-rich fuel. High-entropy alloys (HEAs) seem to be very promising materials to replace commonly used Ni-based alloys. HEAs are the group of materials consisting of at least five main equiatomic elements. These alloys can be doped by other elements in amounts less than 5 at. % in total. Thus, in the present study, NiCoCrAlFe-X alloys are studied in terms of oxidation behavior during exposure to dry and wet atmospheres up to 1000 h. NiCoCrAlFe-X alloys are doped with minor alloying elements in amounts ranging from 1-5 at.%. The effect of the chemical composition on oxidation resistance in dry and wet atmospheres will be shown and discussed.

Keywords: high entropy alloys, oxidation resistance, hydrogen fuel, water vapor

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