Search results for: teachers’ professional development
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 18866

Search results for: teachers’ professional development

4076 Efficient L-Xylulose Production Using Whole-Cell Biocatalyst With NAD+ Regeneration System Through Co-Expression of Xylitol Dehydrogenase and NADH Oxidase in Escherichia Coli

Authors: Mesfin Angaw Tesfay

Abstract:

L-Xylulose is a potentially valuable rare sugar used as starting material for antiviral and anticancer drug development in pharmaceutical industries. L-Xylulose exist in a very low concentration in nature and have to be synthesized from cheap starting materials such as xylitol through biotechnological approaches. In this study, cofactor engineering and deep eutectic solvent were applied to improve the efficiency of L-xylulose production from xylitol. A water-forming NAD+ regeneration enzyme (NADH oxidase) from Streptococcus mutans ATCC 25175 was introduced into E. coli with xylitol-4-dehydrogenase (XDH) of Pantoea ananatis resulting in recombinant cells harboring the vector pETDuet-xdh-SmNox. Further, three deep eutectic solvents (DES) including, Choline chloride/glycerol (ChCl/G), Choline chloride/urea (ChCl/U), and Choline chloride/ethylene glycol (ChCl/EG) have been employed to facilitate the conversion efficiency of L-xylulose from xylitol. The co-expression system exhibited optimal activity at a temperature of 37 ℃ and pH 8.5, and the addition of Mg2+ enhanced the catalytic activity by 1.19-fold. Co-expression of NADH oxidase with XDH enzyme resulted in increased L-xylulose concentration and productivity from xylitol as well as the intracellular NAD+ concentration. Two of the DES used (ChCl/U and ChCl/EG) show positive effects on product yield and the ChCl/G has inhibiting effects. The optimum concentration of ChCl/U was 2.5%, which increased the L-xylulose yields compared to the control without DES. In a 1 L fermenter the final concentration and productivity of L-xylulose from 50 g/L of xylitol reached 48.45 g/L, and 2.42 g/L.h respectively, which was the highest report. Overall, this study is a suitable approach for large-scale production of L-xylulose from xylitol using the engineered E. coli cell.

Keywords: Xylitol-4-dehydrogenase, NADH oxidase, L-xylulose, Xylitol, Coexpression, DESs

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4075 Predictive Factors of Healthcare-Associated Infections and Antibiotic Use Patterns: A Cross-Sectional Survey at the Charles Nicolle Hospital of Tunis

Authors: Nouira Mariem, Ennigrou Samir

Abstract:

Background and aims: Healthcare-associated infections (HAI) represent a major public health problem worldwide. They represent one of the most serious adverse events in health care. The objectives of our study were to estimate the prevalence of HAI at the Charles Nicolle Hospital (CNH) and to identify the main associated factors as well as to estimate the frequency of antibiotic use. Methods: It was a cross-sectional study at the CNH with a unique passage per department (October-December 2018). All patients present at the wards for more than 48 hours were included. All patients from outpatient consultations, emergency, and dialysis departments were not included. The site definitions of infections proposed by the Centers for Disease Control and Prevention (CDC) were used. Only clinically and/or microbiologically confirmed active HAIs were included. Results: A total of 318 patients were included, with a mean age of 52 years and a sex ratio (female/male) of 1.05. A total of 41 patients had one or more active HAIs, corresponding to a prevalence of 13.1% (95% CI: 9.3%-16.9%). The most frequent site infections were urinary tract infections and pneumonia. Multivariate analysis among adult patients (>=18 years) (n=261) revealed that infection on admission (p=0.01), alcoholism (p=0.01), high blood pressure (p=0.008), having at least one invasive device inserted (p=0.004), and history of recent surgery (p=0.03), increased the risk of HAIs significantly. More than 1 of 3 patients (35.4%) were under antibiotics on the day of the survey, of which more than half (57.4%) were under two or more types of antibiotics. Conclusion: The prevalence of HAIs and antibiotic prescriptions at the CNH were considerably high. An infection prevention and control committee, as well as the development of an antibiotic stewardship program with continuous monitoring using repeated prevalence surveys, must be implemented to limit the frequency of these infections effectively.

Keywords: prevalence, healthcare associated infection, antibiotic, Tunisia

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4074 The Benefit of a Universal Screening Program for Lipid Disorders in Two to Ten Years Old Lebanese Children

Authors: Nicolas Georges, Akiki Simon, Bassil Naim, Nawfal Georges, Abi Fares Georges

Abstract:

Introduction: Dyslipidemia has been recognized as a risk factor for cardiovascular diseases. While the development of atherosclerotic lesions begins in childhood and progresses throughout life, data on the prevalence of dyslipidemic children in Lebanon is lacking. Objectives: This study was conducted to assess the benefit of a protocol for universal screening for lipid disorder in Lebanese children aged between two and ten years old. Materials and Methods: A total of four hundred children aged 2 to 10 years old (51.5% boys) were included in the study. The subjects were recruited from private pediatric clinics after parental consent. Fasting total cholesterol (TC), triglycerides (TG), low-density lipoprotein (LDL), high-density lipoprotein (HDL) levels were measured and non-HDL cholesterol was calculated. The values were categorized according to 2011 Expert on Integrated Guidelines for Cardiovascular Health and Risk Reduction in Children and Adolescents. Results: The overall prevalence of high TC ( ≥ 200 mg/dL), high non-HDL-C ( ≥ 145 mg/dL), high LDL ( ≥ 130 mg/dL), high TG ( ≥ 100 mg/dL) and low HDL ( < 40 mg/dL) was respectively 19.5%, 23%, 19%, 31.8% and 20%. The overall frequency of dyslipidemia was 51.7%. In a bivariate analysis, dyslipidemia in children was associated with a BMI ≥ 95ᵗʰ percentile and parents having TC > 240 mg/dL with a P value respectively of 0.006 and 0.0001. Furthermore, high TG was independently associated with a BMI ≥ 95ᵗʰ percentile (P=0.0001). Children with parents having TC > 240 mg/dL was significantly correlated with high TC, high non-HDL-C and high LDL (P=0.0001 for all variables). Finally, according to the Pediatric dyslipidemia screening guidelines from the 2011 Expert Panel, 62.3% of dyslipidemic children had at least 1 risk factor that qualified them for screening while 37.7% of them didn’t have any risk factor. Conclusions: It is preferable to review the latest pediatric dyslipidemia screening guidelines by performing a universal screening program since a third of our dyslipidemic Lebanese children have been missed.

Keywords: cardiovascular risk factors, dyslipidemia, Lebanese children, screening

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4073 Establishment of Virtual Fracture Clinic in Princess Royal Hospital Telford: Experience and Recommendations during the First 9 Months

Authors: Tahir Khaleeq, Patrick Lancaster, Keji Fakoya, Pedro Ferreira, Usman Ahmed

Abstract:

Introduction: Virtual fracture clinics (VFC) have been shown to be a safe and cost-effective way of managing outpatient referrals to the orthopaedic department. During the coronavirus pandemic there has been a push to reduce unnecessary patient contact whilst maintaining patient safety. Materials and Methods: A protocol was developed by the clinical team in collaboration with Advanced Physiotherapy Practitioners (APP) on how to manage common musculoskeletal presentations to A&E prior to COVID as part of routine service development. Patients broadly triaged into 4 categories; discharge with advice, referral to VFC, referral to face to face clinic or discussion with on call team. The first 9 months of data were analysed to assess types of injury seen and outcomes. Results: In total 2489 patients were referred to VFC from internal and external sources. 734 patients were discharged without follow-up and 182 patients were discharged for physiotherapy review. Only 3 patients required admission. Regarding follow-ups, 431 patients had a virtual follow-up while 1036 of patients required further face to face follow up. 87 patients were triaged into subspecialty clinics. 37 patients were felt to have been referred inappropriately. Discussion: BOA guidelines suggest all patients need to be reviewed within 72 hours of their orthopaedic injury. Implementation of a VFC allows this target to be achieved and at the same time reduce patient contact. Almost half the patients were discharged following VFC review, the remaining patients were appropriately followed up. This is especially relevant in the current pandemic where reducing unnecessary trips to hospital will benefit the patient as well as make the most of the resources available.

Keywords: virtual fracture clinic, lockdown, trauma and orthopaedics, Covid- 19

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4072 Integrated Business Model Innovation in Nigerian Higher Education: Challenges and Prospects

Authors: Nonso Ochinanwata, Patrick Oseloka Ezepue

Abstract:

This paper explores challenges and prospects in Nigerian higher education. The paper develops an integrated business model that aimed to innovate Nigeria higher education system. A survey and semi-structured interview among Nigerian higher education academics, students and graduates are used to explore the challenges and prospects. The study provides a comparison between lecturers, students and graduates opinions to evaluate challenges and prospects in Nigerian higher institutions. The study found to achieve efficient and effectiveness innovation in Nigerian higher education, there is a need for higher institutions to collaborate with industry professionals and other stakeholders such as company management, and government policy makers in designing higher education institutions curricula. The study found that the curriculum design and delivery need to blend theoretical understanding and real-life experience from industry, and with social cultural influences related to Nigerian environment. This will enable lecturers to organise their teaching and assessments such that students can learn around theoretical and practical study themes. The curriculum design and delivery need to link the core ideas to challenging problems in society, nationally and globally. Hence, this approach will support business start-ups and social entrepreneurship which resolve key societal problems. The study suggests that higher education executives, directors, deans, head of departments, and even individual academics need to emulate innovative business managers to create value-adding products and services from innovative research and academic work.

Keywords: higher education, curriculum innovation, business model innovation, teaching and research excellence, economic development

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4071 Second-Generation Mozambican Migrant Youth’s Identity and Sense of Belonging in South Africa: The Case of Rural Bushbuckridge, Mpumalanga

Authors: Betty Chiyangwa

Abstract:

This paper explores the complexities surrounding second-generation Mozambican migrant youth’s identity and sense of belonging in post-apartheid South Africa, Bushbuckridge. Established in 1884, Bushbuckridge is one of the earliest districts to accommodate first-generation Mozambicans who migrated to South Africa in the 1970s. This is a single case study informed by data from 24 semi-structured interviews and narratives with migrant youth (18-34 years) born and raised in South Africa to Mozambican parent(s) living in Bushbuckridge. Drawing from Sen’s Capability and Crenshaw’s Intersectionality approaches, this paper contributes to the existing body of knowledge on South to South migration by demonstrating how the role of participants’ identity status influences their agency and capability. The subject of youth migrants is often under-researched in the context of migration in South African thus, their opinions and views have often been marginalized in sociology. Through exploring participants’ experiences, this paper reveals that lack of identity status was described to be a huge hindrance to participants to identify as South Africans and they explained that is a constant distortion of their sense of belonging. Un-documentation status restricts participants and threatens their mobility and hinders their agency to access human rights and perpetuates social inequalities as well as hampering future aspirations. This paper concludes there is a strong association between identity status and levels of social integration. The development of a multi-layered comprehensive model in enhancing participants’ identity is recommended. This model encourages a collaborative effort from multiple stakeholders in enhancing and harnessing migrant youth capabilities in host societies.

Keywords: migrant youth, mozambique, second-generation, south africa

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4070 Library Screening and Evaluation of Mycobacterium tuberculosis Ketol-Acid Reductoisomerase Inhibitors

Authors: Vagolu S. Krishna, Shan Zheng, Estharla M. Rekha, Luke W. Guddat, Dharmarajan Sriram

Abstract:

Tuberculosis (TB) remains a major threat to human health. This due to the fact that current drug treatments are less than optimal as well as the rising occurrence of multi drug-resistant and extensively drug-resistant strains of the etiological agent, Mycobacterium tuberculosis (Mt). Given the wide-spread significance of this disease, we have undertaken a design and evaluation program to discover new anti-TB drug leads. Here, our attention is focused on ketol-acid reductoisomerase (KARI), the second enzyme in the branched-chain amino acid biosynthesis pathway. Importantly, this enzyme is present in bacteria but not in humans, making it an attractive proposition for drug discovery. In the present work, we used high-throughput virtual screening to identify seventeen potential inhibitors of KARI using the Birla Institute of Technology and Science in-house database. Compounds were selected based on high docking scores, which were assigned as the result of favourable interactions between the compound and the active site of KARI. The Ki values for two leads, compounds 14 and 16 are 3.71 and 3.06 µM, respectively for Mt KARI. To assess the mode of binding, 100 ns molecular dynamics simulations for these two compounds in association with Mt KARI were performed and showed that the complex was stable with an average RMSD of less than 2.5 Å for all atoms. Compound 16 showed an MIC of 2.06 ± 0.91 µM and a 1.9 fold logarithmic reduction in the growth of Mt in an infected macrophage model. The two compounds exhibited low toxicity against murine macrophage RAW 264.7 cell lines. Thus, both compounds are promising candidates for development as an anti-TB drug leads.

Keywords: ketol-acid reductoisomerase, macrophage, molecular docking and dynamics, tuberculosis

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4069 Mandatory Wellness Assessments for Medical Students at the University of Ottawa

Authors: Haykal. Kay-Anne

Abstract:

The health and well-being of students is a priority for the Faculty of Medicine at the University of Ottawa. The demands of medical studies are extreme, and many studies confirm that the prevalence of psychological distress is very high among medical students and that it is higher than that of the general population of the same age. The main goal is to identify risk factors for mental health among medical students at the University of Ottawa. The secondary objectives are to determine the variation of these risk factors according to demographic variables, as well as to determine if there is a change in the mental health of students during the 1st and 3rd years of their study. Medical students have a mandatory first and third-year wellness check meeting. This assessment includes a questionnaire on demographic information, mental health, and risk factors such as physical health, sleep, social support, financial stress, education and career, stress and drug use and/or alcohol. Student responses were converted to numerical values and analyzed statistically. The results show that 61% of the variation in the mean of the mental health score is explained by the following risk factors (R2 = 0.61, F (9.396) = 67.197, p < 0.01): lack of sleep and fatigue (β = 0.281, p < 0.001), lack of social support (β = 0.217, p <0.001), poor study or career development (β = 0.195, p < 0.001) and an increase stress and drug and alcohol use (β = -0.239, p < 0.001). No demographic variable has a significant effect on the presence of risk factors. In addition, fixed-effects regression demonstrated significantly lower mental health (p < 0.1) among first-year students (M = 0.587, SD = 0.072) than among third-year students (M = 0.719, SD = 0.071). This preliminary study indicates the need to continue data collection and analysis to increase the significance of the study results. As risk factors are present at the beginning of medical studies, it is important to offer resources to students very early in their medical studies and to have close monitoring and supervision.

Keywords: assessment of mental health, medical students, risk factors for mental health, wellness assessment

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4068 The Association of Smoking and Body Mass Index with Acne Vulgaris in Adolescents and Young Adults

Authors: Almutazballlah Qablan, Jihan M. Muhaidat, Bana Abu Rajab

Abstract:

Background: Acne vulgaris is the most common skin condition that general practitioners and dermatologists encounter. It represents a chronic inflammatory disease affecting the pilosebaceous unit. Although acne vulgaris is not a life-threatening condition, it has a considerable psychological impact on the affected person. Acne patients have poor body image, low self-esteem, social isolation, and restricted activities. As part of the emotional impact, increased levels of anxiety, anger, depression, and frustration have also been observed in acne patients. (1) In this study, we want to assess the association between two modifiable risk factors; BMI and smoking, regarding acne vulgaris. Methods: A case-control study was conducted at King Abdullah University Hospital in Irbid, north Jordan in 2019/2020. A total number of 163 Acne cases were collected and interviewed by the author; on the other hand, there were 162 control cases. Anthropometric measures for Acne patients and control individuals were taken, and BMI was calculated. Both groups were asked about smoking habits. Data on subjects between 14 and 33 years of age were extracted. The characteristics of people who reported acne were compared with those with no acne using univariate and multivariate analysis. The Statistical Package for Social Sciences (SPSS) was relied on to analyze the collected data. The crosstabs methods (chi-square) and odd ratios were relied on to test the study hypothesis. Results: Cigarette smoking was highly associated with no-acne, with an odds ratio of 0.4 (95% CI: 0.2–0.9), P-value = 0.018. BMI and waterpipe smoking were not significantly associated with acne in the multivariate analysis. Conclusion: Cigarette smoking was found to be protective from Acne. No significant relation between BMI nor waterpipe smoking and the development of Acne Vulgaris.

Keywords: acne, BMI, smoking, case-control

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4067 The Impact of Generative AI Illustrations on Aesthetic Symbol Consumption among Consumers: A Case Study of Japanese Anime Style

Authors: Han-Yu Cheng

Abstract:

This study aims to explore the impact of AI-generated illustration works on the aesthetic symbol consumption of consumers in Taiwan. The advancement of artificial intelligence drawing has lowered the barriers to entry, enabling more individuals to easily enter the field of illustration. Using Japanese anime style as an example, with the development of Generative Artificial Intelligence (Generative AI), an increasing number of illustration works are being generated by machines, sparking discussions about aesthetics and art consumption. Through surveys and the analysis of consumer perspectives, this research investigates how this influences consumers' aesthetic experiences and the resulting changes in the traditional art market and among creators. The study reveals that among consumers in Taiwan, particularly those interested in Japanese anime style, there is a pronounced interest and curiosity surrounding the emergence of Generative AI. This curiosity is particularly notable among individuals interested in this style but lacking the technical skills required for creating such artworks. These works, rooted in elements of Japanese anime style, find ready acceptance among enthusiasts of this style due to their stylistic alignment. Consequently, they have garnered a substantial following. Furthermore, with the reduction in entry barriers, more individuals interested in this style but lacking traditional drawing skills have been able to participate in producing such works. Against the backdrop of ongoing debates about artistic value since the advent of artificial intelligence (AI), Generative AI-generated illustration works, while not entirely displacing traditional art, to a certain extent, fulfill the aesthetic demands of this consumer group, providing a similar or analogous aesthetic consumption experience. Additionally, this research underscores the advantages and limitations of Generative AI-generated illustration works within this consumption environment.

Keywords: generative AI, anime aesthetics, Japanese anime illustration, art consumption

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4066 Foreign Artificial Intelligence Investments and National Security Exceptions in International Investment Law

Authors: Ying Zhu

Abstract:

Recent years have witnessed a boom of foreign investments in the field of artificial intelligence (AI). Foreign investments provide critical capital for AI development but also trigger national security concerns of host states. A notable example is an increasing number of cases in which the Committee on Foreign Investment in the United States (CFIUS) has denied Chinese acquisitions of US technology companies on national security grounds. On July 19, 2018, the Congress has reached a deal on the final draft of a new provision to strengthen CFIUS’s authority to review overseas transactions involving sensitive US technology. The question is: how to reconcile the emerging tension between, on the one hand, foreign AI investors’ expectations of a predictable investment environment, and on the other hand, host states’ regulatory power on national security? This paper provides a methodology to reconcile this tension under international investment law. Based on an examination, the national security exception clauses in international investment treaties and the application of national security justification in investor-state arbitration jurisprudence, the paper argues that a traditional interpretation of the national security exception, based on the necessity concept in customary international law, fails to take into account new risks faced by countries, including security concerns over strategic industries such as AI. To overcome this shortage, the paper proposes to incorporate an integrated national security clause in international investment treaties, which includes a two-tier test: a ‘self-judging’ test in the pre-establishment period and a ‘proportionality’ test in the post-establishment period. At the end, the paper drafts a model national security clause for future treaty-drafting practice.

Keywords: foreign investment, artificial intelligence, international investment law, national security exception

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4065 Gender and Geographical Disparity in Editorial Boards of Lithuanian Scientific Journals: An Overview of Different Science Disciplines

Authors: Andrius Suminas

Abstract:

Editors-in-chief and members of editorial boards of scientific journals play an extremely important role in the development of science and assure research integrity, as scientific publications are the major results of research. While gender parity in tenure-track hiring decisions and promotion rates has improved, female academics remain underrepresented in senior career phases, including editors-in-chief and members of editorial boards positions of scientific journals. Journal editors and members of editorial boards exert considerable power over what is published and in certain cases the direction of an academic discipline and the career advancement of authors. For this reason it is important to minimize biases extrinsic to the merit of the work impacting publication decisions. One way to achieve this is to ensure a diverse pool of editors and members of editorial boards, ensuring the widest possible coverage of different competencies. This is in line with a diversity model of editorial appointment where editorial boards are structured to dismantle wider conditions of inequality. Another possible option, a distributive model would seek an editorial board reflective of existing proportions in the field at large. Paper presents comprehensive results of Lithuanian scientific journals study. During the research process were reviewed publicly available information from all scientific journals published in Lithuania to infer the proportions of members of editorial boards by gender and country of affiliation. The results of the study revealed differences the proportions of male and female members of editorial boards in different disciplines of science, as well as clear geographical disparity in Lithianian scientific journals editorial boards.

Keywords: scientific journals, editorial boards of scientific journals, gender disparity, geographical disparity, scientific communication

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4064 Produced Water Treatment Using Novel Solid Scale Inhibitors Based on Silver Tungstate Loaded Kit-6: Static and Modeling Evaluation

Authors: R. Hosny, Mahmoud F. Mubarak, Heba M. Salem, Asmaa A. Abdelrahman

Abstract:

Oilfield scaling is a major problem in the oil and gas industry. Scale issues cost the industry millions of dollars in damage and lost production every year. One of the main causes of global production decline is scale. In this study, solid scale inhibitors based on silver tungstate loaded KIT-6 were synthesized and evaluated in both static and scale inhibition modeling. The silver tungstate loaded KIT-6 catalysts were synthesized via a simple impregnated method using 3D mesoporous KIT-6 as support. The synthesized materials were characterized using wide and low XRD, N2 adsorption–desorption analysis, TGA analysis, and FTIR, SEM, and XPS analysis. The scale inhibition efficiency of the synthesized materials was evaluated using a static scale inhibition test. The results of this study demonstrate the potential application of silver tungstate-loaded KIT-6 solid scale inhibitors for the oil and gas industry. The results of this study will contribute to the development of new and innovative solid scale inhibitors based on silver tungstate-loaded KIT-6. The inhibition efficiency of the scale inhibitor increases, and calcite scale inhibitor decreases with increasing pH (2 to8), it proposes that the scale inhibitor was more effective under alkaline conditions. An inhibition efficiency of 99% on calcium carbonate can be achieved at the optimal dosage of 7.5 ppm at 55oC, indicating that the scale inhibitor exhibits a relatively good inhibition performance on calcium carbonate. The use of these materials can potentially lead to more efficient and cost-effective solutions for scaling inhibition in various industrial processes.

Keywords: produced water treatment, solid scale inhibitors, calcite, silver tungestate, 3 D mesoporous KIT-6, oilfield scales, adsorption

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4063 Competing Interactions, and Magnetization Dynamics in Doped Rare-Earth Manganites Nanostructural System

Authors: Wiqar Hussain Shah

Abstract:

The Structural, magnetic and transport behavior of La1-xCaxMnO3+ (x=0.48, 0.50, 0.52 and 0.55 and =0.015) compositions close to charge ordering, was studied through XRD, resistivity, DC magnetization and AC susceptibility measurements. With time and thermal cycling (T<300 K) there is an irreversible transformation of the low-temperature phase from a partially ferromagnetic and metallic to one that is less ferromagnetic and highly resistive. For instance, an increase of resistivity can be observed by thermal cycling, where no effect is obtained for lower Ca concentration. The time changes in the magnetization are logarithmic in general and activation energies are consistent with those expected for electron transfer between Mn ions. The data suggest that oxygen non-stoichiometry results in mechanical strains in this two-phase system, leading to the development of irreversible metastable states, which relax towards the more stable charge-ordered and antiferromagnetic microdomains at the nano-meter size. This behavior is interpreted in terms of strains induced charge localization at the interface between FM/AFM domains in the antiferromagnetic matrix. Charge, orbital ordering and phase separation play a prominent role in the appearance of such properties, since they can be modified in a spectacular manner by external factor, making the different physical properties metastable. Here we describe two factors that deeply modify those properties, viz. the doping concentration and the thermal cycling. The metastable state is recovered by the high temperature annealing. We also measure the magnetic relaxation in the metastable state and also the revival of the metastable state (in a relaxed sample) due to high temperature (800 ) thermal treatment.

Keywords: Rare-earth maganites, nano-structural materials, doping effects on electrical, magnetic properties, competing interactions

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4062 A High Content Screening Platform for the Accurate Prediction of Nephrotoxicity

Authors: Sijing Xiong, Ran Su, Lit-Hsin Loo, Daniele Zink

Abstract:

The kidney is a major target for toxic effects of drugs, industrial and environmental chemicals and other compounds. Typically, nephrotoxicity is detected late during drug development, and regulatory animal models could not solve this problem. Validated or accepted in silico or in vitro methods for the prediction of nephrotoxicity are not available. We have established the first and currently only pre-validated in vitro models for the accurate prediction of nephrotoxicity in humans and the first predictive platforms based on renal cells derived from human pluripotent stem cells. In order to further improve the efficiency of our predictive models, we recently developed a high content screening (HCS) platform. This platform employed automated imaging in combination with automated quantitative phenotypic profiling and machine learning methods. 129 image-based phenotypic features were analyzed with respect to their predictive performance in combination with 44 compounds with different chemical structures that included drugs, environmental and industrial chemicals and herbal and fungal compounds. The nephrotoxicity of these compounds in humans is well characterized. A combination of chromatin and cytoskeletal features resulted in high predictivity with respect to nephrotoxicity in humans. Test balanced accuracies of 82% or 89% were obtained with human primary or immortalized renal proximal tubular cells, respectively. Furthermore, our results revealed that a DNA damage response is commonly induced by different PTC-toxicants with diverse chemical structures and injury mechanisms. Together, the results show that the automated HCS platform allows efficient and accurate nephrotoxicity prediction for compounds with diverse chemical structures.

Keywords: high content screening, in vitro models, nephrotoxicity, toxicity prediction

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4061 Sublethal Effect of Tebufenozide, an Ecdysteroid Agonist, on the Reproduction of German Cockroach (Blattodea: Blattellidae)

Authors: Samira Kilani-Morakchi, Amina Badi, Nadia Aribi

Abstract:

German cockroach, Blattella germanica, is known to be an important pest due to its high reproductive potential and its ability to build up large infectious populations. The infestations were generally controlled by neurotoxic insecticides including organophosphates (OP), carbamate and pyrethroids. An alternative cockroach’s control approach is the use insect growth regulators (IGRs). The relative fewer effects of these chemicals on non-target insects and animals, and their favourable environmental fate, make them attractive insecticides for inclusion in integrated pest management programmes. The juvenoids and chitin synthesis inhibitors are two classes of IGRs that have received the most attention for useful chemicals to manage German cockroaches while ecdysone agonists were mostly used to control Lepidopteran species. In the present study, the sublethal effects of the non-sreroidal ecdysone agonist tebufenozide were evaluated topically on adults of the B. germanica. The effects on reproduction were observed in adults females of cockroaches that survived exposure to LD25 (146 µg/g of insect) of tebufenozide. Dissection of treated females showed a clear reduction in both the number of oocytes per paired ovaries and the size of basal oocytes, as compared to controls. In addition, tebufenozide significantly reduced the mating success of pairs and altered the fertility as shown through the reduction of ootheca development and total absence of viable nymph. Tebufenozide disrupted the German cockroach reproduction by interfering with homeostasis of the insect hormones. In conclusion, the overall results suggested that tebufenozide can be used as a biorational insecticide for controlling cockroaches.

Keywords: B. germanica, ecdysteroid agonist, tebufenozide, reproduction

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4060 Factors Responsible for Delays in the Execution of Adequately Funded Construction Projects

Authors: Edoghogho Ogbeifun, Charles Mbohwa, J. H. C. Pretorius

Abstract:

Several research report on the factors responsible for the delays in the completion of construction projects has identified the issue of funding as a critical factor; insufficient funding, low cash-flow or lack of funds. Indeed, adequate funding plays pivotal role in the effective execution of construction projects. In the last twenty years (or so), there has been increase in the funds available for infrastructure development in tertiary institution in Nigeria, especially, through the Tertiary Education Trust Fund. This funding body ensures that there is enough fund for each approved project, which is released in three stages during the life of the construction project. However, a random tour of many of the institutions reveals striking evidence of projects not delivered on schedule, to quality and sometime out rightly abandoned. This suggests, therefore, that there are other latent factors, responsible for project delays, that should be investigated. Thus, this research, a pilot scheme, is aimed at unearthing the possible reasons for the delays being experienced in the execution of construction projects for infrastructure upgrade in public tertiary institutions in Nigeria, funded by Tertiary Education Trust Fund. The multiple site case study of qualitative research was adopted. The respondents were the Directors of Physical Planning and the Directors of Works of four Nigerian Public Universities. The findings reveal that delays can be situated within three entities, namely, the funding body, the institutions and others. Therefore, the emerging factors have been classified as external factors (haven to do with the funding body), internal factors (these concern the operations within the institutions) and general factors. The outcome of this pilot exercise provides useful information to guide the Directors as they interact with the funding body as well as challenges themselves to address the loopholes in their internal operations.

Keywords: delays, external factors, funding, general factors, Internal factors

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4059 Role of Green Ecology in Business Development

Authors: Ashfaq Ahmed Kharal

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The study asserts that environment-friendly practices are increasingly being used by businesses throughout the world. Today, there is a great deal of interest in green management from both practitioners and academics. People expect managers to use resources intelligently and responsibly and to minimize the use of water, minerals, and other components in the finished products, as a crucial factor in this passion. The ethical or moral relevance of green management cannot be overstated. Employee Green Behavior (EGB) and environmental sustainability were shown to be significantly influenced by green human resource management (GHRM) in this study. Environmental issues, such as climate change, global warming, and resource conservation have a direct impact on business activities. The environment, society, and economy all suffer as a result of such obstacles. The depletion of natural resources needs immediate replenishment. As a result of government, non-governmental organizations (NGOs), environmental activists, and labor unions putting pressure on businesses and firms are now required to operate in ecologically responsible ways. Organizations are increasingly concerned about environmental sustainability in light of contemporary environmental circumstances and commercial marketplaces. Companies that emphasize long-term viability will benefit from integrating green employee behavior, green human resource management techniques, and environmental sustainability. Competition drives firms to respond to external causes, adapt, and evolve in response to changing conditions in the marketplace. Organizations develop strategic capabilities to transform their resources and acquire a competitive edge while implementing a business plan. The study of GHRM's function is being prioritized since environmental sustainability is becoming a more important strategic goal.

Keywords: EGB, GHRM, environment sustainability, green ecology

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4058 PitMod: The Lorax Pit Lake Hydrodynamic and Water Quality Model

Authors: Silvano Salvador, Maryam Zarrinderakht, Alan Martin

Abstract:

Open pits, which are the result of mining, are filled by water over time until the water reaches the elevation of the local water table and generates mine pit lakes. There are several specific regulations about the water quality of pit lakes, and mining operations should keep the quality of groundwater above pre-defined standards. Therefore, an accurate, acceptable numerical model predicting pit lakes’ water balance and water quality is needed in advance of mine excavation. We carry on analyzing and developing the model introduced by Crusius, Dunbar, et al. (2002) for pit lakes. This model, called “PitMod”, simulates the physical and geochemical evolution of pit lakes over time scales ranging from a few months up to a century or more. Here, a lake is approximated as one-dimensional, horizontally averaged vertical layers. PitMod calculates the time-dependent vertical distribution of physical and geochemical pit lake properties, like temperature, salinity, conductivity, pH, trace metals, and dissolved oxygen, within each model layer. This model considers the effect of pit morphology, climate data, multiple surface and subsurface (groundwater) inflows/outflows, precipitation/evaporation, surface ice formation/melting, vertical mixing due to surface wind stress, convection, background turbulence and equilibrium geochemistry using PHREEQC and linking that to the geochemical reactions. PitMod, which is used and validated in over 50 mines projects since 2002, incorporates physical processes like those found in other lake models such as DYRESM (Imerito 2007). However, unlike DYRESM PitMod also includes geochemical processes, pit wall runoff, and other effects. In addition, PitMod is actively under development and can be customized as required for a particular site.

Keywords: pit lakes, mining, modeling, hydrology

Procedia PDF Downloads 158
4057 Exploring the Determinants of Boko Haram Terrorism in Nigerian Security Systems and Economy

Authors: Abara Onu, Augustine Mina Ephraim, Emmanuel Teidi

Abstract:

Terrorism has been a major challenge and is so dare to the Nigerian government in recent times. The actions and activities of the Islamic sect known as Boko Haram had led to enormous loss of lives and properties in the country, mostly the Northern part of Nigeria. Some of these activities entails bombings, suicide attacks, intimidations, sporadic gunfire of the unarmed, blameless and innocent Nigerians, burning of police stations and churches, kidnappings, raping of school girls and women. Nigeria has also been included amongst one of the terrorist countries of the world. This has serious implications for the development of Nigerian economy. Although, Nigeria had made several worried hard work to deal with these challenges masqueraded by terrorism and insecurity in the country but the rate of insurgency and insecurity is still worrisome. The study looks at exploring the determinants of Boko Haram terrorism in Nigerian security systems and economy. Data used for the study work was from questionnaire administered, using Analysis of Variance (ANOVA) method to analyse the data. The result shows that Ideology and funding are significant basic factors that propelled the Boko Haram group in Nigeria. The Boko Haram disaster poses a significant threat to Nigeria’s economy and the military is the best option and solution in tackling the Boko Haram menace in Nigeria. The work x-rayed the following recommendations; government should declare war on terrorism and as well seek support and cooperation from international communities who in time or the other might have faced with this kind ugly experience and challenge and were able to tackle it. Nigerian Military needs to be more empowered with high dangerous weapons to combat the insurgency as well as beef up security across the Country to curb the threats.

Keywords: terrorism, economy, Boko Haram, Nigeria

Procedia PDF Downloads 261
4056 Investor Beware - Significance of Investor Conduct under the Fair and Equitable Treatment Standard

Authors: Damayanti Sen

Abstract:

The Fair and Equitable Treatment standard has emerged as a core tenet of a formulated legal structure aimed at encouraging investment through the granting of a secure and stable environment for the investor in the Host State. As an absolute, non-contingent standard, it constitutes an independent and reliable system for the protection of the investor and is frequently invoked and applied in investor-state dispute settlement under bilateral and multilateral investment treaties. Thus far, the standard has been examined principally as a measure for determining the responsibility of host countries towards investors and investments. The conduct of investor in applying the Fair and Equitable Treatment Standard is relatively unexplored. Such an assessment may be necessary in light of the development of new defenses to demands of host governments to confine the application of the standard in order to ensure a proper balance between the protection of investors and the inherent right of a State to regulate economic conduct within its borders. This paper explores the implications of including considerations of investor conduct in the determination of whether an act of the host country’s administrative and/or judicial authorities has breached the fair and equitable treatment principle. The need for such defenses are of special concern for governments of developing countries, whose limited resources can affect their ability to provide an effective evaluation of the nature of the proposed investment, and, subsequently, to ensure that the expected benefits are realized. On the basis of conceptual analysis, and emerging international judicial and arbitral case law, this paper suggests that investor duties such as, the avoidance of unconscionable conduct, the reasonable assessment of investment risk in the host country, and a duty to operate an investment reasonably are leading to a new limit upon the fair and equitable treatment standard- one that can be succinctly captured in the phrase “Caveat Investor”.

Keywords: BITs, FET Standard, investor behavior, arbitral case law

Procedia PDF Downloads 313
4055 Ebola Virus Glycoprotein Inhibitors from Natural Compounds: Computer-Aided Drug Design

Authors: Driss Cherqaoui, Nouhaila Ait Lahcen, Ismail Hdoufane, Mehdi Oubahmane, Wissal Liman, Christelle Delaite, Mohammed M. Alanazi

Abstract:

The Ebola virus is a highly contagious and deadly pathogen that causes Ebola virus disease. The Ebola virus glycoprotein (EBOV-GP) is a key factor in viral entry into host cells, making it a critical target for therapeutic intervention. Using a combination of computational approaches, this study focuses on the identification of natural compounds that could serve as potent inhibitors of EBOV-GP. The 3D structure of EBOV-GP was selected, with missing residues modeled, and this structure was minimized and equilibrated. Two large natural compound databases, COCONUT and NPASS, were chosen and filtered based on toxicity risks and Lipinski’s Rule of Five to ensure drug-likeness. Following this, a pharmacophore model, built from 22 reported active inhibitors, was employed to refine the selection of compounds with a focus on structural relevance to known Ebola inhibitors. The filtered compounds were subjected to virtual screening via molecular docking, which identified ten promising candidates (five from each database) with strong binding affinities to EBOV-GP. These compounds were then validated through molecular dynamics simulations to evaluate their binding stability and interactions with the target. The top three compounds from each database were further analyzed using ADMET profiling, confirming their favorable pharmacokinetic properties, stability, and safety. These results suggest that the selected compounds have the potential to inhibit EBOV-GP, offering new avenues for antiviral drug development against the Ebola virus.

Keywords: EBOV-GP, Ebola virus glycoprotein, high-throughput drug screening, molecular docking, molecular dynamics, natural compounds, pharmacophore modeling, virtual screening

Procedia PDF Downloads 23
4054 The Shrinking Nature of Parliamentary Immunity in Kenya: A Proposal for Judicial Restraint

Authors: Oscar Sang, Shadrack David Rotich

Abstract:

Parliamentary immunity is grounded on the notion that parliaments need certain rights or immunities to ensure they can operate independently make fair and impartial decisions without capitulating to political pressure or intimidation. The 2013 election in Kenya marked an important milestone in the development of the law of parliamentary privilege. Such importance relates to the dramatic increase in the number of legislatures in the country from one unicameral parliament, to a bicameral national parliament and forty-seven other regional legislative assemblies. The increase in legislatures has resulted in a dramatic increase in political contestations which have led to legal wrangles. The judiciary in Kenya, once considered submissive, has been invited to arbitrate on various matters pitting individual rights and parliamentary privilege and have invalidated a number of legislative action. While judicial intervention is indeed necessary to ensure that legislatures in Kenya live true to the constitutional aspirations of the Kenyan people, certain judicial decisions have had an effect on eroding parliamentary immunity. This paper highlights a number of instances in which it could be argued that parliamentary privilege came under attack by the courts in Kenya. The paper aims to make a case that while Kenya’s progressive constitution necessitates the scope and extent of legislature’s immunities and privilege to be determined by the courts, it is important that courts exercise restraint in its review of legislative action. The paper makes the argument that unrestrained judicial action in Kenya on questions within the realm parliamentary privilege may undermine the functioning of Kenya’s legislatures. The paper explores approaches taken by a number of jurisdictions in establishing a proper balance between maintaining a viable parliamentary privilege regime in a rights-based constitutional system.

Keywords: Kenya, constitution, judicial restraint, parliamentary privilege

Procedia PDF Downloads 170
4053 Use of Corn Stover for the Production of 2G Bioethanol, Enzymes, and Xylitol Under a Biorefinery Concept

Authors: Astorga-Trejo Rebeca, Fonseca-Peralta Héctor Manuel, Beltrán-Arredondo Laura Ivonne, Castro-Martínez Claudia

Abstract:

The use of biomass as feedstock for the production of fuels and other chemicals of interest is an ever-growing accepted option in the way to the development of biorefinery complexes; in the Mexican state of Sinaloa, two million tons of residues from corn crops are produced every year, most of which can be converted to bioethanol and other products through biotechnological conversion using yeast and other microorganisms. Therefore, the objective of this work was to take advantage of corn stover and evaluate its potential as a substrate for the production of second-generation bioethanol (2G), enzymes, and xylitol. To produce bioethanol 2G, an acid-alkaline pretreatment was carried out prior to saccharification and fermentation. The microorganisms used for the production of enzymes, as well as for the production of xylitol, were isolated and characterized in our workgroup. Statistical analysis was performed using Design Expert version 11.0. The results showed that it is possible to obtain 2G bioethanol employing corn stover as a carbon source and Saccharomyces cerevisiae ItVer01 and Candida intermedia CBE002 with yields of 0.42 g and 0.31 g, respectively. It was also shown that C. intermedia has the ability to produce xylitol with a good yield (0.46 g/g). On the other hand, qualitative and quantitative studies showed that the native strains of Fusarium equiseti (0.4 IU/mL - xylanase), Bacillus velezensis (1.2 IU/mL – xylanase and 0.4 UI/mL - amylase) and Penicillium funiculosum (1.5 IU / mL - cellulases) have the capacity to produce xylanases, amylases or cellulases using corn stover as raw material. This study allowed us to demonstrate that it is possible to use corn stover as a carbon source, a low-cost raw material with high availability in our country, to obtain bioproducts of industrial interest, using processes that are more environmentally friendly and sustainable. It is necessary to continue the optimization of each bioprocess.

Keywords: biomass, corn stover, biorefinery, bioethanol 2G, enzymes, xylitol

Procedia PDF Downloads 171
4052 Bank, Stock Market Efficiency and Economic Growth: Lessons for ASEAN-5

Authors: Tan Swee Liang

Abstract:

This paper estimates bank and stock market efficiency associations with real per capita GDP growth by examining panel-data across three different regions using Panel-Corrected Standard Errors (PCSE) regression developed by Beck and Katz (1995). Data from five economies in ASEAN (Singapore, Malaysia, Thailand, Philippines, and Indonesia), five economies in Asia (Japan, China, Hong Kong SAR, South Korea, and India) and seven economies in OECD (Australia, Canada, Denmark, Norway, Sweden, United Kingdom U.K., and United States U.S.), between 1990 and 2017 are used. Empirical findings suggest one, for Asia-5 high bank net interest margin means greater bank profitability, hence spurring economic growth. Two, for OECD-7 low bank overhead costs (as a share of total assets) may reflect weak competition and weak investment in providing superior banking services, hence dampening economic growth. Three, stock market turnover ratio has negative association with OECD-7 economic growth, but a positive association with Asia-5, which suggest the relationship between liquidity and growth is ambiguous. Lastly, for ASEAN-5 high bank overhead costs (as a share of total assets) may suggest expenses have not been channelled efficiently to income generating activities. One practical implication of the findings is that policy makers should take necessary measures toward financial liberalisation policies that boost growth through the efficiency channel, so that funds are efficiently allocated through the financial system between financial and real sectors.

Keywords: financial development, banking system, capital markets, economic growth

Procedia PDF Downloads 139
4051 A Systematic Review of the Antimicrobial Effects of Different Plant Extracts (Quercus infectoria) as Possible Candidates in the Treatment of Infectious Diseases

Authors: Sajjad Jafari

Abstract:

Background and Aim: The use of herbal medicines has a long history. Today, due to the resistance of microorganisms to antibiotics and antimicrobial substances, herbal medicines have attracted attention due to their significant antimicrobial effects and low toxicity. This study aims to systematically review the antimicrobial effects of different plant extracts (Quercus infectoria) as possible candidates for treating infectious diseases. Material and Methods: The present study is a review study by searching reputable scientific databases such as PubMed, Google Scholar, Scopus, and Web of Science from 2000 to 2023 using the keywords Antimicrobial, Quercus infectoria, Medicinal herbal, Infectious diseases the latest information obtained. Results: In this study, 45 articles were found and reviewed. Quercus infectoria is a small tree native to Greece, Asia Minor, and Iran. Quercus is a plant genus in the family of Fagaceae. This species is generally known under the name ‘‘baloot” in Iran and is commonly used as a medicinal plant. The extracts used included water, hydro-alcoholic, ethanol, methanol. This plant had high inhibition activity and a lethal effect on gram-positive and gram-negative bacteria of ATCC strains, hospital, and resistant strains. Therefore, in addition to antibacterial effects, antiparasitic and antifungal effects. The seed of the plant was the most used and the most effective antimicrobial extract among the ethanol and methanol extracts. Conclusion: The findings of this study suggest that Quercus infectoria has significant antimicrobial effects against a wide range of microorganisms. This makes it a potential candidate for the development of new antimicrobial drugs. Further research is needed to confirm the efficacy and safety of Quercus infectoria in clinical trials.

Keywords: antimicrobial, Quercus infectoria, medicinal herbal, infectious diseases

Procedia PDF Downloads 96
4050 Decline in Melon Yield and Its Contribution to Young Farmers' Diversification into Watermelon Farming in Oyo State, Nigeria

Authors: Oyediran Wasiu Oyeleke

Abstract:

Melon is a popular economic cucurbit in Southwest, Nigeria. In recent time, many young farmers are shifting from melon to watermelon farming due to poor yield and low monetary returns. Hence, this study was carried out to assess the decline in melon yield and its contribution to young farmers’ diversification into watermelon farming in Oyo state, Nigeria. Purposive sampling technique was used in selecting 75 respondents from five villages in Ibarapa block of the Oyo State Agricultural Development Project (ADP). Data collected were analyzed using descriptive statistics and Pearson Product Moment Correlation (PPMC). Results show that majority of the respondents (77.3%) were between 31-40 years of age and 46.70% had secondary school education. Most of the respondents (80%) cultivated more than 3 ha of land for watermelon. Majority of the respondents (74.7%) intercropped melon with other crops while watermelon was cultivated as a sole crop. None of the respondents either grew improved melon seeds (certified seeds) or applied fertilizers but all respondents cultivated treated watermelon seeds, applied fertilizers, and agro-chemicals. The average yields of melon fell from 376.53kg/ha in 2009 to 280.70kg/ha in 2011. However, the respondents were shifting into watermelon production because of available quality seeds and its early maturity, easy harvest, and high sales. There was a significant relationship between melon output and young farmers’ diversification to watermelon in the study area at p < 0.05. The study concluded that decline in the melon yield discouraged youth to continue melon farming in the study area. It is hereby recommended that certified melon seeds should be made available while extension service providers should provide training support for the young farmers in order to reposition and boost melon production in the study area.

Keywords: decline, melon yield, contribution, watermelon, diversification, young farmers

Procedia PDF Downloads 187
4049 Analysis of Enhanced Built-up and Bare Land Index in the Urban Area of Yangon, Myanmar

Authors: Su Nandar Tin, Wutjanun Muttitanon

Abstract:

The availability of free global and historical satellite imagery provides a valuable opportunity for mapping and monitoring the year by year for the built-up area, constantly and effectively. Land distribution guidelines and identification of changes are important in preparing and reviewing changes in the ground overview data. This study utilizes Landsat images for thirty years of information to acquire significant, and land spread data that are extremely valuable for urban arranging. This paper is mainly introducing to focus the basic of extracting built-up area for the city development area from the satellite images of LANDSAT 5,7,8 and Sentinel 2A from USGS in every five years. The purpose analyses the changing of the urban built-up area according to the year by year and to get the accuracy of mapping built-up and bare land areas in studying the trend of urban built-up changes the periods from 1990 to 2020. The GIS tools such as raster calculator and built-up area modelling are using in this study and then calculating the indices, which include enhanced built-up and bareness index (EBBI), Normalized difference Built-up index (NDBI), Urban index (UI), Built-up index (BUI) and Normalized difference bareness index (NDBAI) are used to get the high accuracy urban built-up area. Therefore, this study will point out a variable approach to automatically mapping typical enhanced built-up and bare land changes (EBBI) with simple indices and according to the outputs of indexes. Therefore, the percentage of the outputs of enhanced built-up and bareness index (EBBI) of the sentinel-2A can be realized with 48.4% of accuracy than the other index of Landsat images which are 15.6% in 1990 where there is increasing urban expansion area from 43.6% in 1990 to 92.5% in 2020 on the study area for last thirty years.

Keywords: built-up area, EBBI, NDBI, NDBAI, urban index

Procedia PDF Downloads 174
4048 Syntheses of Biobased Hybrid Poly(epoxy-hydroxyurethane) Polymers

Authors: Adrien Cornille, Sylvain Caillol, Bernard Boutevon

Abstract:

The development of polyurethanes began in 1937 at I. G. Farbenindustrie where Bayer with coworkers discovered the addition polymerization reaction between diisocyanates and diols. Since their discovery, the demand in PU has continued to increase and it will attain in 2016 a production of 18 million tons. However, isocyanates compounds are harmful to human and environment. Methylene diphenyl 4,4’-diisocyanate (MDI) and toluene diisocyanate (TDI), the most widely used isocyanates in PU industry, are classified as CMR (Carcinogen, Mutagen, and Reprotoxic). In order to design isocyanate-free materials, an interesting alternative is the use of Polyhydroxyurethanes (PHUs) by reaction between cyclic carbonate and polyfunctional amines. The main problem concerning PHUs synthesis relates to the low reactivity of carbonate/amine reaction. To solve this issue, many studies in the literature have been conducted to design PHU from more reactive cyclic-carbonates, bearing electro-withdrawing substituent or by using six-membered, seven-membered or thio-cyclic carbonate. The main drawback of all these systems remains the low molar masses obtained for the synthesized PHUs, which hinders their use for material applications. Therefore, we developed another strategy to afford new hybrid PHU with high conversion. This very innovative two-step approach consists in the first step in the synthesis of aminotelechelic PHU oligomers with different chain length from bis-cyclic carbonate with different excess of primary amine functions. In the second step, these aminotelechelic PHU oligomers were used in formulation with biobased epoxy monomers (from cashew nut shell liquid and tannins) to synthesize hybrid polyepoxyurethane polymers. These materials were then characterized by thermal and mechanical analyses.

Keywords: polyurethane, polyhydroxyurethane, aminotelechelic NIPU oligomers, carbonates, epoxy, amine, epoxyurethane polymers, hybrid polymers

Procedia PDF Downloads 214
4047 Solid State Fermentation Process Development for Trichoderma asperellum Using Inert Support in a Fixed Bed Fermenter

Authors: Mauricio Cruz, Andrés Díaz García, Martha Isabel Gómez, Juan Carlos Serrato Bermúdez

Abstract:

The disadvantages of using natural substrates in SSF processes have been well recognized and mainly are associated to gradual decomposition of the substrate, formation of agglomerates and decrease of porosity bed generating limitations in the mass and heat transfer. Additionally, in several cases, materials with a high agricultural value such as sour milk, beets, rice, beans and corn have been used. Thus, the use of economic inert supports (natural or synthetic) in combination with a nutrient suspension for the production of biocontrol microorganisms is a good alternative in SSF processes, but requires further studies in the fields of modeling and optimization. Therefore, the aim of this work is to compare the performance of two inert supports, a synthetic (polyurethane foam) and a natural one (rice husk), identifying the factors that have the major effects on the productivity of T. asperellum Th204 and the maximum specific growth rate in a PROPHYTA L05® fixed bed bioreactor. For this, the six factors C:N ratio, temperature, inoculation rate, bed height, air moisture content and airflow were evaluated using a fractional design. The factors C:N and air flow were identified as significant on the productivity (expressed as conidia/dry substrate•h). The polyurethane foam showed higher maximum specific growth rate (0.1631 h-1) and productivities of 3.89 x107 conidia/dry substrate•h compared to rice husk (2.83x106) and natural substrate based on rice (8.87x106) used as control. Finally, a quadratic model was generated and validated, obtaining productivities higher than 3.0x107 conidia/dry substrate•h with air flow at 0.9 m3/h and C:N ratio at 18.1.

Keywords: bioprocess, scale up, fractional design, C:N ratio, air flow

Procedia PDF Downloads 509