Search results for: solvent effects

Authors: Dawid Sołoducha, Tomasz Borowski, Agata Markowska-Szczupak, Aneta Wesołowska, Marian Kordas, Rafał Rakoczy

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Many studies report varied effects of the magnetic field in medicine, but applications are still missing. Also, essential oils (EOs) were historically used in healing therapies, food preservation and the cosmetic industry due to their wound healing and antioxidant properties and antimicrobial activity. Unfortunately, the chemical characterization of EOs activates its antibacterial action only at a fairly high concentration. They can cause skin reactions, e.g., irritation (irritant contact dermatitis) or allergic contact dermatitis; therefore, they should always be used with caution. However, the administration of EOs to achieve the desired antimicrobial activity and stability with long-term medical usage in low concentration is challenging. The aim of this work was to investigate the antimicrobial activity of commercial Pinus sylvestris L. essential oil from Polish company Avicenna-Oil® under Rotating Magnetic Field (RMF) at f = 1 – 50 Hz. The novel construction of the magnetically assisted self-constructed reactor (MAP) was applied for this study. The chemical composition of essential pine oil was determined by gas chromatography coupled with mass spectrometry (GC-MS). Model bacteria Escherichia coli K12 (ATCC 25922) was used. Different concentrations of pine oil was prepared: 100% 50%, 25%, 12.5% and 6.25%. The disc diffusion and MIC test were done. To examine the effect of essential pine oil and rotating magnetic field RMF on antibacterial performance agar plate method was used. Pine oil consist of α-pinene (28.58%), β-pinene (17.79%), δ-3-carene (14.17%) and limonene (11.58%). The present study indicates the exposition to the RMF, as compared to the unexposed controls causing an increase in the efficacy of antibacterial properties of pine oil. We have shown that the rotating magnetic fields (RMF) at a frequency, f, between 25 Hz to 50 Hz, increase the antimicrobial efficiency of oil at lower than 50% concentration. The new method can be applied in many fields e.g. aromatherapy, medicine as a component of dressing, or as food preservatives.

Keywords: rotating magnetic field, pine oil, antimicrobial activity, Escherichia coli

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Authors: Affiah D. U., Katuri I. P., Emefiene M. E., Amienyo C. A.

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Broccoli (Brassica oleraceae L., var. italica) is one of the most important vegetables that is high in nutrients and bioactive compounds. It easily grown on a wide range of soil types and is adaptable to many different climatic conditions. This study was carried out within Jos North and environs in vitro to evaluate Neem (Azadirachta indica) leaves extract against Albugo candida, the causative agent of white blisters disease of broccoli. Through the survey, prevalence and incidence were accessed and a fluffy white growth symptom on the underside of leaves was also observed on the field. Infected leaves samples were collected from three different farms namely: Farin Gada, Naraguta, and Juth and the organism associated with the disease was isolated. Pathogenicity test carried out revealed the fungal isolate Albugo candida to be responsible for the disease. Antimicrobial susceptibility test was performed using agar well diffusion method to determine the minimum inhibitory concentrations of two extract of Azadirachta indica leaves against the organism. Ethanolic extract had the highest antifungal activities of 3.30±0.21 - 17.61± 0.11 while aqueous extract had the least antifungal activities of 0.00±0.00 - 13.23±0.12. The minimum inhibitory concentration of aqueous was 100 mg/ml while its minimum fungicidal concentration was at 200 mg/ml. For ethanol, the minimum inhibitory concentration was 50 mg/ml while its minimum fungicidal concentration was 100 mg/ml. Plants being less toxic in usage over synthetic or inorganic chemicals makes them easy to handle, easily accessible and renewable. Due to the biosafety of plant extracts and its availability since the plant-based extracts of the two different solvents were found to be effective against the test organism hence, it is recommended for in-depth research to make it readily available for control of other pathogens and pests.

Keywords: antifungal, biocontrol, broccoli, fungi

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Authors: Florina Magdalena Anichitoae, Anca Dobrean, Ionut Stelian Florean

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Due to the fact that cyberbullying victimization is an increasing problem nowadays, affecting more and more children and adolescents around the world, we wanted to take a step forward analyzing this phenomenon. So, we took a look at some variables which haven't been studied together before, trying to develop another way to view cyberbullying victimization. We wanted to test the effects of the mother, father, and peer attachment on adolescent involvement in cyberbullying as victims through unconditional self acceptance. Furthermore, we analyzed each subscale of the IPPA-R, the instrument we have used for parents and peer attachment measurement, in regards to cyberbullying victimization through unconditional self acceptance. We have also analyzed if gender and age could be taken into consideration as moderators in this model. The analysis has been performed on 653 adolescents aged 11-17 years old from Romania. We used structural equation modeling, working in R program. For the fidelity analysis of the IPPA-R subscales, USAQ, and Cyberbullying Test, we have calculated the internal consistency index, which varies between .68-.91. We have created 2 models: the first model including peer alienation, peer trust, peer communication, self acceptance and cyberbullying victimization, having CFI=0.97, RMSEA=0.02, 90%CI [0.02, 0.03] and SRMR=0.07, and the second model including parental alienation, parental trust, parental communication, self acceptance and cyberbullying victimization and had CFI=0.97, RMSEA=0.02, 90%CI [0.02, 0.03] and SRMR=0.07. Our results were interesting: on one hand, cyberbullying victimization is predicted by peer alienation and peer communication through unconditional self acceptance. Peer trust directly, significantly, and negatively predicted the implication in cyberbullying. In this regard, considering gender and age as moderators, we found that the relationship between unconditional self acceptance and cyberbullying victimization is stronger in girls, but age does not moderate the relationship between unconditional self acceptance and cyberbullying victimization. On the other hand, regarding the degree of cyberbullying victimization as being predicted through unconditional self acceptance by parental alienation, parental communication, and parental trust, this hypothesis was not supported. Still, we could identify a direct path to positively predict victimization through parental alienation and negatively through parental trust. There are also some limitations to this study, which we've discussed in the end.

Keywords: adolescent, attachment, cyberbullying victimization, parents, peers, unconditional self-acceptance

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Authors: Sachini Wickramanayaka

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The occurrence of natural disasters has increased in an alarming rate in recent times due to escalating effects of climate change. One such natural disaster that has continued to grow in frequency and intensity is ‘flooding’, adversely affecting communities around the globe. This is an exploration on how architecture can intervene and facilitate in preserving communities in the face of disaster, specifically in battling floods. ‘Resilience’ is one of the concepts that have been brought forward to be instilled in vulnerable communities to lower the impact from such disasters as a preventative and coping mechanism. While there are number of ways to achieve resilience in the built environment, this paper aims to create a synthesis between resilience and ‘urban acupuncture’. It will consider strengthening communities from within, by layering a network of relatively small-scale, fast phased interventions on pre-existing conventional flood preventative large-scale engineering infrastructure.By investigating ‘The Woodlands’, a planned neighborhood as a case study, this paper will argue that large-scale water management solutions while extremely important will not suffice as a single solution particularly during a time of frequent and extreme weather events. The different projects will try to synthesize non-architectural aspects such as neighborhood aspirations, requirements, potential and awareness into a network of architectural forms that would collectively increase neighborhood resiliency to floods. A mapping study of the selected study area will identify the problematic areas that flood in the neighborhood while the empirical data from previously implemented case studies will assess the success of each solution.If successful the different solutions for each of the identified problem areas will exhibithow flooding and water management can be integrated as part and parcel of daily life.

Keywords: acupuncture, architecture, resiliency, micro-interventions, neighborhood

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Authors: Raif Parlakkaya, Mustafa Nihat Demirci, Mehmet Nuri Salur

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Environmental pollution has detrimental effects on the quality of our life and its scope has reached such an extent that measures are being taken both at the national and international levels to reduce, prevent and mitigate its impact on social, economic and political spheres. Therefore, awareness of environmental problems has been increasing among stakeholders and accordingly among companies. It is seen that corporate reporting is expanding beyond environmental performance. Primary purpose of publishing an environmental report is to provide specific audiences with useful, meaningful information. This paper is intended to analyze the extent and qualification of environmental disclosures of Turkish publicly quoted firms and see how it varies from one sector to another. The data for the study were collected from annual activity reports of companies, listed on the corporate governance index (BIST-XKURY) of Istanbul Stock Exchange. Content analysis was the research methodology used to measure the extent of environmental disclosure. Accordingly, 2015 annual activity reports of companies that carry out business in some particular fields were acquired from Capital Market Board, websites of Public Disclosure Platform and companies’ own websites. These reports were categorized into five main aspects: Environmental policies, environmental management systems, environmental protection and conservation activities, environmental awareness and information on environmental lawsuits. Subsequently, each component was divided into several variables related to what each firm is supposed to disclose about environmental information. In this context, the nature and scope of the information disclosed on each item were assessed according to five different ways (N.I: No Information; G.E.: General Explanations; Q.E.: Qualitative Detailed Explanations; N.E.: Quantitative (numerical) Detailed Explanations; Q.&N.E.: Both Qualitative and Quantitative Explanations).

Keywords: environmental accounting, disclosure, corporate governance, content analysis

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Authors: Ann Dashwood

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Using Standard Australian English with confidence is a cultural expectation of parents of primary school aged children who want to engage effectively with their children’s teachers and school administration. That confidence in support of their children’s learning at school is seldom experienced by parents whose first language is not English. Sharing language with competence in an intercultural environment is the common denominator for meaningful communication and engagement to occur in a school community. Experience in relevant, interactive sessions is known to enhance engagement and participation. The purpose of this paper is to identify a pedagogy for parents otherwise isolated from daily use of functional Australian cultural language learned to engage effectively in their children’s learning at school. The outcomes measure parents’ intercultural engagement with classroom teachers and attention to the school’s administrative procedures using quantitative and qualitative methods. A principled communicative task-based language learning approach, combined with intercultural communication strategies provide the theoretical base for intensive English inquiry-based learning and engagement. The quantitative analysis examines data samples collected by classroom teachers and administrators and parents’ writing samples. Interviews and observations qualitatively inform the study. Currently, significant numbers of projects are active in community centers and schools to enhance English language knowledge of parents from Language Backgrounds Other Than English (LBOTE). The study is significant to explore the effects of an intensive English pedagogy with parents of varied English language backgrounds, by targeting inquiry-based language use for social interactions in the school and wider community, specific engagement and cultural interaction with teachers and school activities and procedures.

Keywords: engagement, intercultural communication, language teaching pedagogy, LBOTE, school community

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Authors: Longkui Zhu, Zhengcao Li

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High temperature gas-cooled reactors (HTGRs) are considered as one of the next-generation advanced nuclear reactors, in which porous nuclear graphite is used as neutron moderators, reflectors, structure materials, and cooled by inert helium. Radioactive tritium and ¹⁴C are generated in terms of reactions of thermal neutrons and ⁶Li, ¹⁴N, ¹⁰B impurely within nuclear graphite and the coolant during HTGRs operation. Currently, hydrogen and nitrogen diffusion behavior together with nuclear graphite microstructure evolution were investigated to minimize the radioactive waste release, using thermogravimetric analysis, X-ray computed tomography, the BET and mercury standard porosimetry methods. It is found that the peak value of graphite weight loss emerged at 573-673 K owing to nitrogen diffusion from graphite pores to outside when the system was subjected to vacuum. Macropore volume became larger while porosity for mesopores was smaller with temperature ranging from ambient temperature to 1073 K, which was primarily induced by coalescence of the subscale pores. It is suggested that the porous nuclear graphite should be first subjected to vacuum at 573-673 K to minimize the nitrogen and the radioactive 14°C before operation in HTGRs. Then, results on hydrogen diffusion show that the diffusible hydrogen and tritium could permeate into the coolant with diffusion coefficients of > 0.5 × 10⁻⁴ cm²·s⁻¹ at 50 bar. As a consequence, the freshly-generated diffusible tritium could release quickly to outside once formed, and an effective approach for minimizing the amount of radioactive tritium is to make the impurity contents extremely low in nuclear graphite and the coolant. Besides, both two- and three-dimensional observations indicate that macro and mesopore volume along with total porosity decreased with temperature at 50 bar on account of synergistic effects of applied compression strain, sharpened pore morphology, and non-uniform temperature distribution.

Keywords: advanced high temperature gas-cooled reactor, hydrogen and nitrogen diffusion, microstructure evolution, nuclear graphite, radioactive waste management

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Authors: Elif Cakir, Görkem Özülkü, Hatice Bekiroğlu, Muhammet Arici, Osman Sağdic

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It is important to be able to formulate cakes with a wide consumption mass with gluten-free and high nutritional value ingredients to increase the consumption possibilities of people with limited nutrition opportunities. Although people do not prefer Prunus spinosa (PS)because of its sour taste and its use in the food industry is limited on a local scale, the potential of using PS, which is a naturally rich source of many micronutrients and bioactive compounds, in glutenfree cake production has been investigated. In this study, the potential of using PS, a natural wild fruit, in the production of functional gluten-free cakes was investigated. It was aimed to evaluate the effects of freeze-dried and powdered PS-enriched rice flour cakes on tech functionality, nutrition and eating quality. In terms of physicochemical properties, PS raises increased the ash, protein, and moisture values of the cakes. PS with high phenolic content, phenolic component content, and radical reducing power made by ABTS, FRAP, and DPPH techniques were higher in all samples than control, and the highest 4% PS was determined in cakes. In terms of the glycemic index (GI), which is an important feature of diet products, it was determined that the GI in cakes decreased by 86.30±1.04.75.05±1.16 and 69.38±1.21, respectively, with the increase in PS ratio. Except for the 1%, PS added sample, the increase in PS caused a decrease in specific volume, % porosity and increase in hardness, including 4 days of storage. PS increase decreased the L* and b* values and increased a* value and redness of the cake. Sensory liking of the cake samples containing PS was scored significantly (p<0.05) higher of control.

Keywords: Prunus spinosa, gluten-free cake, antioxidant, phenolic, glycemic index

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Authors: Salma A. El-Marasy, Reham M. Abd-Elsalam, Omar A. Ahmed-Farid

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Dementia is characterized by impairments in memory and other cognitive abilities. This study aims to elucidate the possible ameliorative effect of silymarin on scopolamine-induced dementia using the object recognition test (ORT). The study was extended to demonstrate the role of cholinergic activity, oxidative stress, neuroinflammation, brain neurotransmitters and histopathological changes in the anti-amnestic effect of silymarin in demented rats. Wistar rats were pretreated with silymarin (200, 400, 800 mg/kg) or donepezil (10 mg/kg) orally for 14 consecutive days. Dementia was induced after the last drug administration by a single intraperitoneal dose of scopolamine (16 mg/kg). Then behavioral, biochemical, histopathological, and immunohistochemical analyses were then performed. Rats pretreated with silymarin counteracted scopolamine-induced non-spatial working memory impairment in the ORT and decreased acetylcholinesterase (AChE) activity, reduced malondialdehyde (MDA), elevated reduced glutathione (GSH), restored gamma-aminobutyric acid (GABA) and dopamine (DA) contents in the cortical and hippocampal brain homogenates. Silymarin dose-dependently reversed scopolamine-induced histopathological changes. Immunohistochemical analysis showed that silymarin dose-dependently mitigated protein expression of a glial fibrillary acidic protein (GFAP) and nuclear factor kappa-B (NF-κB) in the brain cortex and hippocampus. All these effects of silymarin were similar to that of the standard anti-amnestic drug, donepezil. This study reveals that the ameliorative effect of silymarin on scopolamine-induced dementia in rats using the ORT maybe in part mediated by, enhancement of cholinergic activity, anti-oxidant and anti-inflammatory activities as well as mitigation in brain neurotransmitters and histopathological changes.

Keywords: dementia, donepezil, object recognition test, rats, silymarin, scopolamine

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Authors: Syeda Fahria Hoque Mimmi

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Many new and promising treatments for reducing or diminishing the adverse effects of microorganisms are being discovered day by day. On the other hand, the dairy industry is accelerating the economic wheel of Bangladesh. Considering all these facts, new thoughts were developed to isolate milk proteins by the present experiment for opening up a new era of developing natural antibiotics from milk. Lactoferrin, an iron-binding glycoprotein with multifunctional properties, is crucial to strengthening the immune system and also useful for commercial applications. The protein’s iron-binding capacity makes it undoubtedly advantageous to immune system modulation and different bacterial strains. For fulfilling the purpose, 4 of raw and 17 of commercially available milk samples were collected from different farms and stores in Bangladesh (Dhaka, Chittagong, and Cox’s Bazar). Protein quantification by nanodrop technology has confirmed that raw milk samples have better quantities of protein than the commercial ones. All the samples were tested for their antimicrobial activity against 18 pathogens, where raw milk samples showed a higher percentage of antibacterial activity. In addition to this, SDS-PAGE (Sodium Dodecyl Sulfate–Polyacrylamide Gel Electrophoresis) was performed to identify lactoferrin in the milk samples. Lactoferrin was detected in 9 samples from which 4 were raw milk samples. Interestingly, Streptococcus pyogenes, Klebsiella pneumoniae, Bacillus cereus, Pseudomonas aeruginosa, Vibrio cholera, Staphylococcus aureus, and enterotoxigenic E. coli significantly displayed sensitivity against lactoferrin collected from raw milk. Only Bacillus cereus, Pseudomonas aeruginosa, Streptococcus pneumonia, Enterococcus faecalis, and ETEC (Enterotoxigenic Escherichia coli) were susceptible to lactoferrin obtained from a commercial one. This study suggested that lactoferrin might be used as the potential alternative of antibiotics for many diseases and also can be used to reduce microbial deterioration in the food and feed industry.

Keywords: alternative of antibiotics, commercially available milk, lactoferrin, nanodrop technology, pathogens, raw milk

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Authors: M. Bagheri Varzaneh, H. R. Rahmani, R. Jahanian

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The present study aimed to investigate the effects of copper-methionine on ascites incidence and hematological, morphological and enzymatic responses in broiler chickens. A total of 480 one-day-old Ross 308 broiler chicks were used in a completely randomized design in a 2×3 factorial arrangement of treatments including two ambient temperatures (thermoneutral and cold stress) and three copper levels (0, 100, and 200 mg/kg as copper-methionine) with 4 replicates (20 birds in each replicate). Broilers were kept in an environmentally-controlled room from 1 to 28 days; then, half of them exposed to cold temperature from 28 to 45 days of age. The birds were sacrificed at days 38 and 45 of age. Heparinized blood samples were collected to measure hematocrit, hemoglobin concentration, red blood cell (RBC) count, alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Heart, lungs, liver, and spleen were collected and weighed separately on a sensitive digital scale. At d 38 of age, none of hematological variables, enzymatic parameters, and relative weights of organs were affected by treatments. Ascitic broilers were observed in group subjected to cold temperature and control diet (without supplemental copper) at d 45 of age. Relative weight of lungs and relative weight of heart in broilers fed on copper-methionine supplemented diets in cold temperature were lower compared with other groups. Relative liver weight, ALT, AST activities, and hematological parameters such as hematocrit, hemoglobin concentration, red blood cell count in ascitic broilers were significantly increased. In contrast, a significant decrease of the relative weight of spleen was shown in these chickens. The results showed that dietary supplementation with copper–methionine can decrease probability of ascites incidence in broilers chicks, especially under cold condition.

Keywords: ascites, cold temperature, copper-methionine, cold-stressed broiler

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Authors: Balázs Ádám, Randi Nørgaard Fløe Pedersen, Jørgen Riis Jepsen

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Volatile chemicals that accumulate and release from freight containers constitute significant health risks. Fumigation to prevent spread of pests and off-gassing of freight are sources of hazardous chemicals. The aim of our study was to investigate the regulation and practice of container handling with focus on preventive measures applied against chemical exposures in Denmark. A comprehensive systematic search of scientific literature and organizational domains of international and Danish regulatory bodies was performed to explore regulations related to safe work with transport containers. The practice of container work was investigated in a series of semi-structured interviews with managers and health and safety representatives of organizations that handle transport containers. Although there are several international and national regulations and local safety instructions that relate to container handling, the provided information is not specific or up-to-date enough to conduct safe practice in many aspects. The interviewees estimate high frequency of containers with chemical exposure and deem that they can potentially damage health, although recognizable health effects are rare. Knowledge is limited about the chemicals and most of them cannot be measured by available devices. Typical preventive measures are passive ventilation and personal protective equipment but their use is not consistent and may not provide adequate protection. Hazardous chemicals are frequently present in transport containers; however, managers, workers and even occupational health professionals have limited knowledge about the problem. Detailed risk assessment and specific instructions on risk management are needed to provide safe conditions for work with containers.

Keywords: chemical exposure, fumigation, occupational health and safety regulation, transport container

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Authors: Rewadee Watakakosol, Arunya Tuicomepee, Panrapee Suttiwan, Sakkaphat T. Ngamake

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Health problems caused by alcohol consumption not only have short-term effects at the time of drinking but also leave long-lasting health conditions. Teenagers who start drinking in their middle-high or high school years or before entering college have higher likelihood to increase their alcohol use and abuse, and they were found to be less healthy compared with their non-drinking peers when entering adulthood. This study aimed to examine factors that predict intention and readiness to reduce and quit alcohol consumption among Thai teenagers. Participants were 826 high-school and vocational school students, most of whom were females (64.4%) with the average age of 16.4 (SD = 0.9) and the average age of first drinking at 13.7 (SD = 2.2). Instruments included the scales that developed based on the Theory of Planned Behaviour theoretical framework. They were the Attitude toward Alcohol Reduction and Cessation Scale, Normative Group and Influence Scale, Perceived Behavioral Control toward Alcohol Reduction and Cessation Scale, Behavioral Intent toward Alcohol Reduction and Cessation Scale, and Readiness to Reduce and Quit Alcohol Consumption Scale. Findings revealed that readiness to reduce / quit alcohol was the most powerful predictive factor (β=. 53, p < .01), followed by attitude of easiness in alcohol reduction and cessation (β=.46, p < .01), perceived behavioral control toward alcohol reduction and cessation (β =.41, p < .01), normative group and influence (β=.15, p < .01), and attitude of being accepted from alcohol reduction and cessation (β = -.12, p < .01), respectively. Attitude of improved health after alcohol reduction and cessation did not show statistically significantly predictive power. All factors significantly predict teenagers’ alcohol reduction and cessation behavior and accounted for 59 percent of total variance of alcohol consumption reduction and cessation.

Keywords: alcohol consumption reduction and cessation, intention, readiness to change, Thai teenagers

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Authors: Mohammed Badereldien, Rezk Diab, Mohamoud Ali, Ayman Aboelkassem

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The stone surfaces of historical architectural heritage in Egypt are under threat from of various environmental factors such as temperature fluctuation, humidity, pollution, and microbes. Due to these factors, the facades of buildings are deteriorating deformation and disfiguration of external decoration and the formation of black accretion also often from the stone works. The aim of this study is to evaluate the effectiveness of CaCO₃ nano-particles as consolidation and protection material for calcareous stone monuments. Selected tests were carried out in order to estimate the superficial consolidating and protective effect of the treatment. When applied the nanoparticles dispersed in the acrylic copolymer; poly ethylmethacrylate (EMA)/methylacrylate (MA) (70/30, respectively) (EMA)/methylacrylate (MA) (70/30, respectively). The synthesis process of CaCO₃ nanoparticles/polymer nano-composite was prepared using in situ emulsion polymerization system. The consolidation and protection were characterized by TEM, while the penetration depth, re-aggregating effects of the deposited phase, and the surface morphology before and after treatment were examined by SEM (Scanning Electron Microscopy). Improvement of the stones' mechanical properties was evaluated by compressive strength tests. Changes in water-interaction properties were evaluated by water absorption capillarity measurements, and colorimetric measurements were used to evaluate the optical appearance. Together the results appear to demonstrate that CaCO₃/polymer nanocomposite is an efficient material for the consolidation of limestone architecture and monuments. As compared with samples treated with pure acrylic copolymer without Calcium carbonate nanoparticles, for example, CaCO₃ nanoparticles are completely compatible, strengthening limestone against thermal aging and improving its mechanical properties.

Keywords: calcium carbonate nanoparticles, consolidation, nanocomposites, calcareous stone, colorimetric measurements, compressive strength

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Authors: Yu-Chieh Chen, Li-Yun Wang, Chi-Chih Chen, Huy Hùng Đào, Ya-Mei Chen, Ming-Chu Cheng, Wen-Bin Chung, Hso-Chi Chaung, Guan-Ming Ke

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Many recent researches have demonstrated that CD154, a protein primarily expressed on activated T cell molecules, has potentially acted as a molecular adjuvant to improve the immunogenicity of subunit vaccines against viral infections. Classical swine fever (CSF) affects the swine industry worldwide that is one of the most devastating and highly contagious pig diseases. It is listed by the World Organization for Animal Health (OIE) as an infectious animal disease that must be reported. Although pigs vaccinated with subunit vaccines can be differentially diagnosed from those infected animals, subunit vaccines usually need adjuvants to enhance and elicit immune responses. In this study, CD154 was linked with CSFV E2 sequences and then expressed in CHO cells to produce the fusion protein as E2-CD154. The porcine specific CpG adjuvant was also used in one of the formulations. The specific pathogen-free pigs (SPF) at the age of 4-week-old were randomly separated into four groups, vaccinated with E2-CpG, E2-CD154, E2-CD154-CpG or the commercial Bayovac® CSF-E2 vaccine and boosted two weeks after primary vaccination. The results showed that the percentages of CD4+ and CD4+IL2+ in peripheral blood mononuclear cells (PBMC) in E2-CD154 vaccinated piglets seven days after primary vaccination were gained by 1-5% relative to the control group. In addition, the percentages of CD4+IFNγ+ T cells had slightly edged up 0.1-0.3% compared with the control group. Also, increased E2-specific IFNγ levels had edged up CD4+CD8+ T cells found in E2-CD154 and E2-CD154-CpG groups, particularly in the E2-CD154-CpG group. These results implicate that CD154 may enhance cellular immunity and synergistically act with species-specific CpG adjuvant as a dual-phase adjuvant. Therefore, the CD154 may be beneficial as a promising adjuvant in subunit vaccines.

Keywords: CD154, CpG adjuvant, cellular immunity, subunit vaccine, pig

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Authors: Jibril Mohammed, Usman Dadum Hamza, Muhammad Idris Misau, Baba Yahya Danjuma, Yusuf Bode Raji, Abdulsalam Surajudeen

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Volatile organic compounds (VOCs) have been reported to be responsible for many acute and chronic health effects and environmental degradations such as global warming. In this study, a renewable and low-cost coconut shell activated carbon (PHAC) was synthesized and treated with ammonia (PHAC-AM) to improve its hydrophobicity and affinity towards VOCs. Removal efficiencies and adsorption capacities of the ammonia treated activated carbon (PHAC-AM) for benzene and toluene were carried out through batch and fixed-bed studies respectively. Langmuir, Freundlich and Tempkin adsorption isotherms were tested for the adsorption process and the experimental data were best fitted by Langmuir model and least fitted by Tempkin model; the favourability and suitability of fitness were validated by equilibrium parameter (RL) and the root square mean deviation (RSMD). Judging by the deviation of the predicted values from the experimental values, pseudo-second-order kinetic model best described the adsorption kinetics than the pseudo-first-order kinetic model for the two VOCs on PHAC and PHAC-AM. In the fixed-bed study, the effect of initial VOC concentration, bed height and flow rate on benzene and toluene adsorption were studied. The highest bed capacities of 77.30 and 69.40 mg/g were recorded for benzene and toluene respectively; at 250 mg/l initial VOC concentration, 2.5 cm bed height and 4.5 ml/min flow rate. The results of this study revealed that ammonia treated activate carbon (PHAC-AM) is a sustainable adsorbent for treatment of VOCs in polluted waters.

Keywords: volatile organic compounds, equilibrium and kinetics studies, batch and fixed bed study, bio-based activated carbon

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Authors: Adeline Fontvieille, Hugo Parent-Roberge, Marie-France Langlois, Tamas Fulop, Michel Pavic, Eleonor Riesco

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Introduction: Total lean body mass is reduced during cancer treatment. This loss is called cancer cachexia and is accompanied by a progressive loss of fat mass. In older adults, these body composition changes can have a larger impact on metabolic health, physical autonomy, and cancer survival. Although currently untreatable, exercise training could reduce these effects. Hence, the objective of this pilot study is to investigate if 12 weeks of exercise training during cancer treatment can mitigate the loss of muscle mass and fat mass in older adults. Methods: A total of 40 older adults (65-80 years) with an ongoing treatment for a curable cancer are currently recruited and randomised in two groups: 1) Combined training (EX, n=20) and 2) Control group (CON, n=20). All variables are measured before and after 12 weeks of intervention: Anthropometry (weight, height, body mass index), body composition (total fat mass, visceral adipose tissue, total and appendicular muscle mass; DXA), metabolic profile (HDL-C and LDL-C, triglycerides, glucose and insulin levels). Results: Preliminary analyses revealed no impact of exercise training on appendicular muscle mass (p=0,31) and fat mass (p=0,31). Furthermore, total body weight, waist circumference, HDL-cholesterol, LDL-cholesterol, glucose and insulin levels remained unchanged (all p ≥ 0.79) after 12 weeks of training. However, statistical analyses revealed that triglyceride levels slightly increased (p=0.03), irrespective of the group. Conclusion: Preliminary analyses did not reveal any impact of aerobic and resistance exercise training on body composition in oncogeriatric patients. Furthermore, exercise training seems not efficient to prevent the cancer treatment-related triglyceride levels increase.

Keywords: muscle mass, fat mass, metabolic profile, combined training, aging, cancer

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Authors: Ekaterina Zubkova, Irina Beloglazova, Iurii Stafeev, Konsyantin Dergilev, Yelena Parfyonova, Mikhail Menshikov

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Mesenchymal stromal cells from adipose tissue (MSC) currently are widely used in regenerative medicine to restore the function of damaged tissues, but that is significantly hampered by their heterogeneity. One of the modern approaches to overcoming this obstacle is the polarization of cell subpopulations into a specific phenotype under the influence of cytokines and other factors that activate receptors and signal transmission to cells. We polarized MSC with factors affecting the inflammatory signaling and functional properties of cells, followed by verification of their expression profile and ability to affect the polarization of macrophages. RT-PCR evaluation showed that cells treated with LPS, interleukin-17, tumor necrosis factor α (TNF α), primarily express pro-inflammatory factors and cytokines, and after treatment with polyninosin polycytidic acid and interleukin-4 (IL4) anti-inflammatory factors and some proinflammatory factors. MSC polarized with pro-inflammatory cytokines showed a more robust pro-angiogenic effect in fibrin gel bead 3D angiogenesis assay. Further, we evaluated the possibility of paracrine effects of MSCs on the polarization of intact macrophages. Polarization efficiency was assesed by expression of M1/M2 phenotype markers CD80 and CD206. We showed that conditioned media from MSC preincubated in the presence of IL-4 cause an increase in CD206 expression similar to that observed in M2 macrophages. Conditioned media from MSC polarized in the presence of LPS or TNF-α increased the expression of CD80 antigen in macrophages, similar to that observed in M1 macrophages. In other cases, a pronounced paracrine effect of MSC on the polarization of macrophages was not detected. Thus, our study showed that the polarization of MSC along the pro-inflammatory or anti-inflammatory pathway allows us to obtain cell subpopulations that have a multidirectional modulating effect on the polarization of macrophages. (RFBR grants 20-015-00405 and 18-015-00398.)

Keywords: angiogenesis, cytokines, mesenchymal, polarization, inflammation

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Authors: Aleksandar M. Radojković, Jovana M. Ćirković, Sanja Z. Perać, Jelena N. Jovanović, Zorica M. Branković, Slobodan D. Milanović, Ivan Lj. Milenković, Jovan N. Dobrosavljević, Nemanja V. Simović, Vanja M. Tadić, Ana R. Žugić, Goran O. Branković

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In many parts of the world, various Phytophthora species pose a serious threat to forests and crops. With the rapidly growing international trade in plants and the ongoing impacts of climate change, the harmful effects of plant pathogens of the genus Phytophthora are increasing, damaging the biodiversity and sustainability of forest ecosystems. This genus is one of the most destructive plant pathogens, causing the majority of fine root (66%) and collar rot diseases (90%) of woody plant species worldwide. Eco-friendly biopesticides, based on plant-derived products, such as essential oils (EOs), are one of the promising solutions to this problem. In this study, among three different EOs investigated (Chamaecyparis lawsoniana (A. Murr.) Parl., Thuja plicata Donn ex D.Don and Juniperus communis L.), western red cedar (Thuja plicata) essential oil almost completely inhibited the growth of three Phytophthora species (P. plurivora Jung and Burgess, P. quercina Jung, and P. ×cambivora (Petri) Buisman) during seven days of exposure for the EO concentrations of 0.1% and 0.5% (v/v). To prolong the inhibiting effect, Thuja plicata EO was encapsulated into a biopolymer matrix consisting of a chitosan-gelatin mixture to form a water-in-oil emulsion. This approach allowed the prolonged effect of the essential oil by its slow release from the biopolymer matrix and protection of the active components from atmospheric influences. Thus, it was demonstrated that encapsulated Thuja plicata EO consisting of sustainable bioproducts is efficient in controlling of Phytophthora species and can be considered a means of protection in natural and semi-natural ecosystems.

Keywords: emulsions, essential oils, phytophthora, thuja plicata

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Authors: Doostishoar Farzad, Forootanfar Hamid, Hasan-Bikdashti Morvarid, Faramarzi Mohammad Ali, Ameri Atefe

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Introduction: Chili peppers and related plants in the family of capsaicum produce a mixture of capsaicins represent anticarcinogenic, antimutagenic, and chemopreventive properties. Vanillylamine, the main product of capsaicin hydrolysis is applied as a precursor for manufacturing of natural vanillin (a famous flavor). It is also used in the production of synthetic capsaicins harboring a wide variety of physiological and biological activities such as antibacterial and anti-inflammatory effects as well as enhancing of adrenal catecholamine secretion, analgesic, and antioxidative activities. The ability of some lipases, such as Novozym 677 BG and Novozym 435 and also some proteases e.g. trypsine and penicillin acylase, in capsaicin hydrolysis and green synthesis of vanillylamine has been investigated. In the present study the optimized culture broth of a newly isolated lipase-producing bacterial strain (Stenotrophomonas maltophilia) applied for the hydrolysis of capsaicin. Materials and methods: In order to compare hydrolytic activity of optimized and basal culture broth through capsaicin 2 mL of each culture broth (as sources of lipase) was introduced to capsaicin solution (500 mg/L) and then the reaction mixture (total volume of 3 mL) was incubated at 40 °C and 120 rpm. Samples were taken every 2 h and analyzed for vanillylamine formation using HPLC. Same reaction mixture containing boiled supernatant (to inactivate lipase) designed as blank and each experiment was done in triplicate. Results: 215 mg/L of vanillylamine was produced after the treatment of capsaicin using the optimized medium for 18 h, while only 61 mg/L of vanillylamine was detected in presence of the basal medium under the same conditions. No capsaicin conversion was observed in the blank sample, in which lipase activity was suppressed by boiling of the sample for 10 min. Conclusion: The application of optimized broth culture for the hydrolysis of capsaicin led to a 43% conversion of that pungent compound to vanillylamine.

Keywords: Capsaicin, green synthesis, lipase, stenotrophomonas maltophilia

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Authors: Passant Youssef, Ahmed El-Tair, Amr El-Nemr

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Lately, with the environmental changes, enthusiasts trigger to stop the contamination of environment. Thus, various efforts were exerted for innovating environmental friendly concrete to sustain as a ‘Green Building’ material. Green building materials consider the cement industry as one of the most sources of air pollutant with high rate of carbon dioxide (CO₂) emissions. Several methods were developed to extensively reduce the influence of cement industry on environment. These methods such as using supplementary cementitious material or improving the cement manufacturing process are still under investigation. However, with the presence of recycled wastes from construction and finishing materials, the use of supplementary cementitious materials seems to provide an economic solution. Furthermore, it improves the mechanical properties of cement paste, in addition to; it modulates the workability and durability of concrete. In this paper, the glass powder was considered to be used as partial replacement of cement. This study provided the mechanical influence for using the glass powder as partial replacement of cement. In addition, it examines the microstructure of cement mortar using scanning electron microscope and X-ray diffraction. The cement in concrete is replaced by waste glass powder in steps of 5%, 10%, 15%, 20% and 25% by weight of cement and its effects on compressive and flexure strength were determined after 7 and 28 days. It was found that the 5% glass powder replacement increased the 7 days compressive strength by 20.5%, however, there was no increase in compressive strength after 28 days; which means that the glass powder did not react in the cement mortar due to its amorphous nature on the long run, and it can act as fine aggregate better that cement replacement. As well as, the 5% and 10% glass powder replacement increased the 28 days flexural strength by 46.9%. SEM micrographs showed very dense matrix for the optimum specimen compared to control specimen as well; some glass particles were clearly observed. High counts of silica were optimized from XRD while amorphous materials such as calcium silicate cannot be directly detected.

Keywords: supplementary materials, glass powder, concrete, cementitious materials

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Authors: E. Mattio

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The aim of this project is to study the Chinese presence in Ethiopia, following the path of the last salt caravans from Danakil to Tigray region. Official estimates of the number of Chinese in Africa vary widely; on the continent, there are increasingly diverse groups of Chinese migrants in terms of language, dialect, class, education, and employment. Based on this and on a very general state of the art, it was decided to increase the studies on this phenomenon, documenting the extraction of salt and following the sellers in the north of the country. The project is unique and allows you to admire a landscape that will soon change, due to the construction of infrastructure that is changing the dynamics of movement and sales. To carry out this study, interdisciplinary investigation methods were integrated, such as landscape archeology, historiographic research, participatory anthropology, geopolitics, and cultural anthropology and ethnology. There are two main objectives of the research. The first was an analysis of risk perceptions to predict what will happen to these populations and how the territory will be modified, trying to monitor the growth of infrastructure in the country and the effects it will have on the population. Thanks to the use of GIS, some roads created by Chinese companies that worked in the area have been georeferenced. The second point was to document the life and rituals of Ethiopian populations, in order not to lose the aspects of uniqueness that risk being lost. The local interviews have garnered impressions and criticisms from the local population to understand whether the Chinese presence is perceived as a threat or a solution. Among the most exclusive interviews, there are those made to Afar leaders in the Logya area and some Coptic representatives in the Wukro area. To make this project even more unique, the Coptic rituals of Gennà and Timkat have been documented, unique expressions of a millennial tradition. The aim was to understand whether the Maoist presence began to influence the religious rites and forms of belief present in the country.

Keywords: China, Ethiopia, GIS, risk perceptions

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Authors: A. Paz, S. Cortés Diéguez, J. M. Cruz, A. B. Moldes, J. M. Domínguez

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Synthetic dyes are extensively used in the paper, food, leather, cosmetics, pharmaceutical and textile industries. Wastewater resulting from their production means several environmental problems. Improper disposal of theirs effluents involves adverse impacts and not only about the colour, also on water quality (Total Organic Carbon, Biological Oxygen Demand, Chemical Oxygen Demand, suspended solids, salinity, etc.) on flora (inhibition of photosynthetic activity), fauna (toxic, carcinogenic, and mutagenic effects) and human health. The aim of this work is to optimize the decolourisation process of different types of dyes by Bacillus aryabhattai. Initially, different types of dyes (Indigo Carmine, Coomassie Brilliant Blue and Remazol Brilliant Blue R) and suitable culture media (Nutritive Broth, Luria Bertani Broth and Trypticasein Soy Broth) were selected. Then, a central composite design (CCD) was employed to optimise and analyse the significance of each abiotic parameter. Three process variables (temperature, salt concentration and agitation) were investigated in the CCD at 3 levels with 2-star points. A total of 23 experiments were carried out according to a full factorial design, consisting of 8 factorial experiments (coded to the usual ± 1 notation), 6 axial experiments (on the axis at a distance of ± α from the centre), and 9 replicates (at the centre of the experimental domain). Experiments results suggest the efficiency of this strain to remove the tested dyes on the 3 media studied, although Trypticasein Soy Broth (TSB) was the most suitable medium. Indigo Carmine and Coomassie Brilliant Blue at maximal tested concentration 150 mg/l were completely decolourised, meanwhile, an acceptable removal was observed using the more complicate dye Remazol Brilliant Blue R at a concentration of 50 mg/l.

Keywords: Bacillus aryabhattai, dyes, decolourisation, central composite design

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Authors: Auwal Garba, Rabiu Maijama’a, Abdullahi Muhammad Jalam

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Variability in climate has affected the agricultural production all over the globe. This concern has motivated important changes in the field of research during the last decade. Climate variability is believed to have declining effects towards rice production in Nigeria. This study examined climate variability and its impact on rice productivity in Dass Local Government Area, Bauchi State, by employing Linear Trend Model (LTM), analysis of variance (ANOVA) and regression analysis. Annual seasonal data of the climatic variables for temperature (min. and max), rainfall, and solar radiation from 1990 to 2015 were used. Results confirmed that 74.4% of the total variation in rice yield in the study area was explained by the changes in the independent variables. That is to say, temperature (minimum and maximum), rainfall, and solar radiation explained rice yield with 74.4% in the study area. Rising mean maximum temperature would lead to reduction in rice production while moderate increase in mean minimum temperature would be advantageous towards rice production, and the persistent rise in the mean maximum temperature, in the long run, will have more negatively affect rice production in the future. It is, therefore, important to promote agro-meteorological advisory services, which will be useful in farm planning and yield sustainability. Closer collaboration among the meteorologist and agricultural scientist is needed to increase the awareness about the existing database, crop weather models among others, with a view to reaping the full benefits of research on specific problems and sustainable yield management and also there should be a special initiative by the ADPs (State Agricultural Development Programme) towards promoting best agricultural practices that are resilient to climate variability in rice production and yield sustainability.

Keywords: climate variability, impact, productivity, rice

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Authors: Chang-Fa Liu, Yi-Ting Wang, Yuan Liu, Hai-Feng Wei, Lei Fang, Jin Li

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Heavy metals in sediments can cause adverse ecological effects while it exceeds a given criteria. The present study investigated sediment environmental quality, pollutant enrichment, ecological risk, and source identification for copper, cadmium, lead, zinc, mercury, and arsenic in the sediments collected from tidal flat marsh of Shuangtai estuary, China. The arithmetic mean integrated pollution index, geometric mean integrated pollution index, fuzzy integrated pollution index, and principal component score were used to characterize sediment environmental quality; fuzzy similarity and geo-accumulation Index were used to evaluate pollutant enrichment; correlation matrix, principal component analysis, and cluster analysis were used to identify source of pollution; environmental risk index and potential ecological risk index were used to assess ecological risk. The environmental qualities of sediment are classified to very low degree of contamination or low contamination. The similar order to element background of soil in the Liaohe plain is region of Sanjiaozhou, Honghaitan, Sandaogou, Xiaohe by pollutant enrichment analysis. The source identification indicates that correlations are significantly among metals except between copper and cadmium. Cadmium, lead, zinc, mercury, and arsenic will be clustered in the same clustering as the first principal component. Copper will be clustered as second principal component. The environmental risk assessment level will be scaled to no risk in the studied area. The order of potential ecological risk is As > Cd > Hg > Cu > Pb > Zn.

Keywords: ecological risk assessment, heavy metals, sediment, marsh, Shuangtai estuary

Procedia PDF Downloads 351

Authors: Lenore Van Den Berg

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Vocabulary development is positively associated with reading development, reading comprehension, and academic achievement. It is frequently stated that South Africa is in the midst of a literacy crisis. The past 24 years since the first democratically elected government have not revolutionised the education system; rather, after various curriculum changes and continued struggles to incorporate all 11 official languages as languages of instruction, research shows that 78 per cent of South African Grade 4 learners are functionally illiterate. The study sets out to find solutions to this problem and to add to the research base on vocabulary acquisition by assessing the effect of integrating the principles of explicit, interactive vocabulary instruction, within the context of storybook reading, on Grade 1 vocabulary acquisition. Participants comprised of 69 Grade 1 English second language learners from three classes in two government primary schools. The two schools differ in socio-economic status (SES), with School A having a lower SES than School B. One Grade 1 class was randomly assigned to be the Experimental Group, while two other classes served as control groups. The intervention took place for a period of 18 weeks and consisted of 30-minute storybook reading sessions, accompanied by interactive vocabulary instruction, twice a week. The Peabody Picture Vocabulary Test IV (PPVT-IV) was the diagnostic test administered to all learners before the intervention, as a pre-test, and after the interventions as a post-test. Data regarding excising vocabulary instruction practices and approaches were also collected through classroom observations and individual, semi-structured interviews with the Experimental Group’s teacher. Findings suggest that second language storybook reading, accompanied by explicit, interactive vocabulary instruction, have a positive impact on Grade 1 vocabulary acquisition but that vocabulary teaching practices and socio-economic status also play a key role in vocabulary acquisition.

Keywords: interactive vocabulary instruction, second language vocabulary, storybook reading, vocabulary acquisition, reading development, PPVT

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Authors: Justin Nwabanne, Sam Omenyi, Jeremiah Chukwuneke

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This work presents structural nonlinear static analysis of a horizontal taut cable using Finite Element Analysis (FEA) method. The FEA was performed analytically to determine the tensions at each nodal point and subsequently, performed based on finite element displacement method computationally using the FEA software, ANSYS 14.0 to determine their behaviour under the influence of aerodynamic forces imposed on the cable. The convergence procedure is adapted into the method to prevent excessive displacements through the computations. The work compared the two FEA cases by examining the effectiveness of the analytical model in describing the response with few degrees of freedom and the ability of the nonlinear finite element procedure adopted to capture the complex features of cable dynamics with reference to the aerodynamic external influence. Results obtained from this work explain that the analytic FEM results without aerodynamic influence show a parabolic response with an optimum deflection at nodal points 12 and 13 with the cable weight at nodes 12 and 13 having the value -1.002936N while for the cable tension shows an optimum deflection value for nodes 12 and 13 at -189396.97kg/km. The maximum displacement for the cable system was obtained from ANSYS 14.0 as 4483.83 mm for X, Y and Z components of displacements at node number 2 while the maximum displacement obtained is 4218.75mm for all the directional components. The dynamic behaviour of a taut cable investigated has application in a typical power transmission line. Aerodynamic influences on the cables were considered using FEA approach by employing ANSYS 14.0 showed a complex modal behaviour as expected.

Keywords: aerodynamics, cable tension and weight, finite element analysis, nodal, non-linear model, optimum deflection, suspended cable, transmission line

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Authors: Edison E. Haro, Akindele G. Odeshi, Jerzy A. Szpunar

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Hybrid bio-composites are developed for use in protective armor through positive hybridization offered by reinforcement of high-density polyethylene (HDPE) with Kevlar short fibers and palm wood micro-fillers. The manufacturing process involved a combination of extrusion and compression molding techniques. The mechanical behavior of Kevlar fiber reinforced HDPE with and without palm wood filler additions are compared. The effect of the weight fraction of the added palm wood micro-fillers is also determined. The Young modulus was found to increase as the weight fraction of organic micro-particles increased. However, the flexural strength decreased with increasing weight fraction of added micro-fillers. The interfacial interactions between the components were investigated using scanning electron microscopy. The influence of the size, random alignment and distribution of the natural micro-particles was evaluated. Ballistic impact and dynamic shock loading tests were performed to determine the optimum proportion of Kevlar short fibers and organic micro-fillers needed to improve impact strength of the HDPE. These results indicate a positive hybridization by deposition of organic micro-fillers on the surface of short Kevlar fibers used in reinforcing the thermoplastic matrix leading to enhancement of the mechanical strength and dynamic impact behavior of these materials. Therefore, these hybrid bio-composites can be promising materials for different applications against high velocity impacts.

Keywords: hybrid bio-composites, organic nano-fillers, dynamic shocking loading, ballistic impacts, energy absorption

Procedia PDF Downloads 117

Authors: Qin Ou, Yanghui Xu, Xintu Wang, Kim Maren Lompe, Gang Liu, Jan Peter Van Der Hoek

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Microplastics (MPs) can undergo the photooxidation process under ultraviolet (UV) exposure, which determines their transformation and fate in environments. The presence of dissolved organic matter (DOM) can interact with MPs and take participate in the photo-degradation of MPs. As an important DOM component, dissolved black carbon (DBC), widely distributed in aquatic environments, can accelerate or inhibit the sunlight-driven photo-transformation of environmental pollutants. However, the role and underlying mechanism of DBC in the photooxidation of MPs are not clear. Herein, the DBC (< 0.45 µm) was extracted from wood biochar and fractionated by molecular weight (i.e., <3 KDa, 3 KDa−30 KDa, 30 KDa−0.45 µm). The effects of DBC chemical composition (i.e., molecular weight and chemical structure) in DBC-mediated photo-transformation of polystyrene (PS) MPs were investigated. The results showed that DBC initially inhibited the photo-degradation of MPs due to light shielding. Under UV exposure for 6−24 h, the presence of 5 mg/L DBC decreased the carbonyl index of MPs compared to the control. This inhibitory effect of DBC was found to decrease with increasing irradiation time. Notably, DBC initially decreased but then increased the hydroxyl index with aging time, suggesting that the role of DBC may shift from inhibition to acceleration. In terms of the different DBC fractions, the results showed that the smallest fraction of DBC (<3 KDa) significantly accelerated the photooxidation of PS MPs since it acted as reactive oxygen species (ROS) generators, especially in promoting the production of ¹O₂ and ³DBC* and •OH. With the increase in molecular weight, the acceleration effect of DBC on the degradation of MPs was decreased due to the increase of light shielding and possible decrease of photosensitization ability. This study thoroughly investigated the critical role of DBC chemical composition in the photooxidation process, which helps to assess the duration of aging and transformation of MPs during long-term weathering in natural waters.

Keywords: microplastics, photo-degradation, dissolved black carbon, molecular weight, photosensitization

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Authors: Koustav Pal, Indranil Das

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In recent times, perovskite and double perovskite (DP) systems attracts lot of interest as they provide a rich material platform for studying emergent functionalities like near-room-temperature ferromagnetic (FM) insulators, exchange bias (EB), magnetocaloric effects, colossal magnetoresistance, anisotropy, etc. These interesting phenomena emerge because of complex couplings between spin, charge, orbital, and lattice degrees of freedom in these systems. Various magnetic phenomena such as exchange bias, spin glass, memory effect, colossal magneto-resistance, etc. can be modified and controlled through antisite (B-site) disorder or controlling oxygen concentration of the material. By controlling oxygen concentration in SrFe0.5Co0.5O3 – δ (SFCO) (δ ∼ 0.3), we achieve intrinsic exchange bias effect with a large exchange bias field (∼1.482 Tesla) and giant coercive field (∼1.454 Tesla). Now we modified the B-site by introducing 10% iridium in the system. This modification give rise to the exchange bias field as high as 1.865 tesla and coercive field 1.863 tesla. Our work aims to investigate the effect of oxygen deficiency and B-site effect on exchange bias in oxide materials for potential technological applications. Structural characterization techniques including X-ray diffraction, scanning tunneling microscopy, and transmission electron microscopy were utilized to determine crystal structure and particle size. X-ray photoelectron spectroscopy was used to identify valence states of the ions. Magnetic analysis revealed that oxygen deficiency resulted in a large exchange bias due to a significant number of ionic mixtures. Iridium doping was found to break interaction paths, resulting in various antiferromagnetic and ferromagnetic surfaces that enhance exchange bias.

Keywords: coercive field, disorder, exchange bias, spin glass

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