Search results for: dermal exposure

Authors: Michael Bach

Abstract:

Extensive weld repair was carried out in 2009 after a leak was detected in the aluminum 5052 vessel of the National Research Universal (NRU) reactor. This was the second vessel installed since 1974. In support of the NRU vessel leak repair and fitness for service assessments, an estimate of property changes due to irradiation exposure is required to extend the service of the reactor until 2018. In order to fully evaluate the property changes in the vessel wall, an Iodine-125 rod (I rod) made from the same material and irradiated in the NRU reactor from 1974 1991, was retrieved and sectioned for microstructure characterization and mechanical testing. The different sections of the I rod were exposed to various levels of thermal neutron fluences from 0 to a maximum of 11.9 x 1022 n/cm2. The end of life thermal neutron fluence of the NRU vessel is estimated to be 2.2 x 1022 n/cm2 at 35 years of service. Tensile test and fracture toughness test was performed on the I-rod material at various axial locations. The changes in tensile properties were attributed primarily to the creation of finely dispersed Mg-Si precipitates that harden the material and reduced the ductility. Despite having a reduction in fracture toughness, the NRU vessel is still operation at the current fluence levels.

Keywords: aluminum alloy, fitness-for-service assessment , fracutre toughness, nuclear reactor, precipitate strengthening, radiation damage, tensile strength

Procedia PDF Downloads 173

Authors: Keivan Davami, Michael Munther, Lloyd Hackel

Abstract:

The control of properties and material behavior by implementing thermal-mechanical processes is based on mechanical deformation and annealing according to a precise schedule that will produce a unique and stable combination of grain structure, dislocation substructure, texture, and dispersion of precipitated phases. The authors recently developed a thermal-mechanical technique to stabilize the microstructure of additively manufactured nickel-based superalloys even after exposure to high temperatures. However, the mechanism(s) that controls this stability is still under investigation. Laser peening (LP), also called laser shock peening (LSP), is a shock based (50 ns duration) post-processing technique used for extending performance levels and improving service life of critical components by developing deep levels of plastic deformation, thereby generating high density of dislocations and inducing compressive residual stresses in the surface and deep subsurface of components. These compressive residual stresses are usually accompanied with an increase in hardness and enhance the material’s resistance to surface-related failures such as creep, fatigue, contact damage, and stress corrosion cracking. While the LP process enhances the life span and durability of the material, the induced compressive residual stresses relax at high temperatures (>0.5Tm, where Tm is the absolute melting temperature), limiting the applicability of the technology. At temperatures above 0.5Tm, the compressive residual stresses relax, and yield strength begins to drop dramatically. The principal reason is the increasing rate of solid-state diffusion, which affects both the dislocations and the microstructural barriers. Dislocation configurations commonly recover by mechanisms such as climbing and recombining rapidly at high temperatures. Furthermore, precipitates coarsen, and grains grow; virtually all of the available microstructural barriers become ineffective.Our results indicate that by using “cyclic” treatments with sequential LP and annealing steps, the compressive stresses survive, and the microstructure is stable after exposure to temperatures exceeding 0.5Tm for a long period of time. When the laser peening process is combined with annealing, dislocations formed as a result of LPand precipitates formed during annealing have a complex interaction that provides further stability at high temperatures. From a scientific point of view, this research lays the groundwork for studying a variety of physical, materials science, and mechanical engineering concepts. This research could lead to metals operating at higher sustained temperatures enabling improved system efficiencies. The strengthening of metals by a variety of means (alloying, work hardening, and other processes) has been of interest for a wide range of applications. However, the mechanistic understanding of the often complex processes of interactionsbetween dislocations with solute atoms and with precipitates during plastic deformation have largely remained scattered in the literature. In this research, the elucidation of the actual mechanisms involved in the novel cyclic LP/annealing processes as a scientific pursuit is investigated through parallel studies of dislocation theory and the implementation of advanced experimental tools. The results of this research help with the validation of a novel laser processing technique for high temperature applications. This will greatly expand the applications of the laser peening technology originally devised only for temperatures lower than half of the melting temperature.

Keywords: laser shock peening, mechanical properties, indentation, high temperature stability

Procedia PDF Downloads 132

Authors: Bidya Dhar Sahu, Meghana Koneru, R. Shyam Sunder, Ramakrishna Sistla

Abstract:

Environmental and occupational exposure to hexavalent chromium [Cr(VI)] via textile manufacture, metallurgy, spray paints, stainless steel industries, drinking water containing chromium are often known to cause acute renal injury in humans and animals. Nephrotoxicity is the major effect of chromium poisoning. In the present study, we investigated the potential renoprotective effect and underlying mechanisms of carvedilol using rat model of potassium dichromate (K2Cr2O7)-induced nephrotoxicity. Exploration of the underlying mechanisms of carvedilol revealed that carvedilol attenuated nuclear translocation and DNA binding activity of NF-κB (p65), restored antioxidant and mitochondrial respiratory enzyme activities and attenuated apoptosis related protein expressions in kidney tissues. The serum levels of TNF-α, the renal iNOS and myeloperoxidase activity were significantly decreased in carvedilol pre-treated K2Cr2O7-induced nephrotoxic rats. These results were further supported and confirmed by histological findings. In conclusion, the findings of the present study demonstrated that carvedilol is an effective chemoprotectant against K2Cr2O7-induced nephrotoxicity in rats.

Keywords: apoptosis, carvedilol, inflammation, potassium dichromate-induced nephrotoxicity, applied pharmacology

Procedia PDF Downloads 262

Authors: Cosette Maiky

Abstract:

Background: In the context of the Syrian crisis, the past few years have witnessed an exponential growth in the number of refugee mental health studies, which have essentially focused either on the affected Syrian population and/or host communities. However, the Palestinian communities in the region did not receive sufficient that much of attention. Aim: The study aimed at identifying trends and patterns of mental health and and psychosocial conditions among Palestinian refugees in the context of the Syrian crisis, including the recognition of gaps in appropriate services. Methods: The research model comprised a systematic documentary review, a mapping of available contextual analyses, a quantitative survey, focus group discussions as well as key informant interviews (with relevant stakeholders and beneficiaries). Findings: Content analysis revealed multiple effects of transgenerational transmission of trauma among Palestinian refugees in the context of the Syrian crisis, which showed to be neither linear nor one-dimensional occurrence. In addition to highlights on exposure to traumatic events and psychological sequelae, the review outlines the most prevailing coping mechanisms and essential protective factors. Conclusion: Away from a trauma-centered or symptom-focused exercise, practitioners may take account of the present study to better focus research and intervention methodologies.

Keywords: Palestine refugees, Syria crisis, psychosocial, mental health

Procedia PDF Downloads 333

Authors: Laila Seada, Hanan Oreiby, Fawaz Al Rashid, Ashraf Negm

Abstract:

Background and Objective: In most areas of the world, the incidence of thyroid cancer has been increasing over the last decade, mostly due to a combination of early detection of the neoplasm resulting from sensitive procedures and increased population exposure to radiation and unrecognized carcinogens. Methods: Cases of thyroid cancer have been retrieved from the cancer registry at King Khalid Hospital during the period from August 2012 to April 2016. Age, gender and histopathologic types have been recorded. Results: Thyroid carcinoma ranked as the second most common malignancy in females (25%) after breast cancer (31%). It constituted 20.8% of all newly diagnosed cancer cases. As for males, it ranked the 4^th type of malignancy after gastrointestinal cancer, lymphomas and soft tissue sarcomas. Mean age for females and males was 38.7 +/- 13.2 and 60.25 +/- 11.5 years, respectively, and the difference between the two groups was statistically significant (p value = 0.0001). Fifty-five (82%) were papillary carcinomas including 10 follicular variant of papillary (FVPC), and eight papillary micro carcinomas (PMC) and two tall cell/oncocytic variants. Follicular carcinomas constituted two (3.1%), while two (3.1%) were anaplastic, and two (3.1%) were medullary. Conclusion: Thyroid cancer incidence in Hail is ranking as the 2^nd most common female malignancy similar to other regions in the Kingdom. However, this high incidence contrasts with much lower rates worldwide.

Keywords: thyroid, hail, papillary, microcarcinoma

Procedia PDF Downloads 289

Authors: Danielle Slomberg, Jerome Labille, Riccardo Catalano, Jean-Claude Hubaud, Alexandra Lopes, Alice Tagliati, Teresa Fernandes

Abstract:

In the assessment and management of cosmetics and personal care products, sunscreens are of emerging concern regarding both human and environmental health. Organic UV blockers in many sunscreens have been evidenced to undergo rapid photodegradation, induce dermal allergic reactions due to skin penetration, and to cause adverse effects on marine systems. While mineral UV-blockers may offer a safer alternative, their fate and impact and resulting regulation are still under consideration, largely related to the potential influence of nanotechnology-based products on both consumers and the environment. Nanometric titanium dioxide (TiO₂) UV-blockers have many advantages in terms of sun protection and asthetics (i.e., transparency). These UV-blockers typically consist of rutile nanoparticles coated with a primary mineral layer (silica or alumina) aimed at blocking the nanomaterial photoactivity and can include a secondary organic coating (e.g., stearic acid, methicone) aimed at favouring dispersion of the nanomaterial in the sunscreen formulation. The nanomaterials contained in the sunscreen can leave the skin either through a bathing of everyday usage, with subsequent release into rivers, lakes, seashores, and/or sewage treatment plants. The nanomaterial behaviour, fate and impact in these different systems is largely determined by its surface properties, (e.g. the nanomaterial coating type) and lifetime. The present work aims to develop the eco-design of sunscreens through the minimisation of risks associated with nanomaterials incorporated into the formulation. All stages of the sunscreen’s life cycle must be considered in this aspect, from its manufacture to its end-of-life, through its use by the consumer to its impact on the exposed environment. Reducing the potential release and/or toxicity of the nanomaterial from the sunscreen is a decisive criterion for its eco-design. TiO₂ UV-blockers of varied size and surface coating (e.g., stearic acid and silica) have been selected for this study. Hydrophobic TiO₂ UV-blockers (i.e., stearic acid-coated) were incorporated into a typical water-in-oil (w/o) formulation while hydrophilic, silica-coated TiO₂ UV-blockers were dispersed into an oil-in-water (o/w) formulation. The resulting sunscreens were characterised in terms of nanomaterial localisation, sun protection factor, and photo-passivation. The risk to the direct aquatic environment was assessed by evaluating the release of nanomaterials from the sunscreen through a simulated laboratory aging procedure. The size distribution, surface charge, and degradation state of the nano-composite by-products, as well as their nanomaterial concentration and colloidal behaviour were determined in a variety of aqueous environments (e.g., seawater and freshwater). Release of the hydrophobic nanocomposites into the aqueous environment was driven by oil droplet formation while hydrophilic nano-composites were readily dispersed. Ecotoxicity of the sunscreen by-products (from both w/o and o/w formulations) and their risk to marine organisms were assessed using coral symbiotes and tropical corals, evaluating both lethal and sublethal toxicities. The data dissemination and provided risk knowledge from the present work will help guide regulation related to nanomaterials in sunscreen, provide better information for consumers, and allow for easier decision-making for manufacturers.

Keywords: alteration, environmental fate, sunscreens, titanium dioxide nanoparticles

Procedia PDF Downloads 249

Authors: G. E. Okungbowa, H. O. Adams, S. E. Eze

Abstract:

This study is on the estimation of adult patient doses for Chest X-ray diagnostic examinations of new admitted undergraduate students attending a tertiary institution health centre as part of their routine clearance and check up on admitted into the institution. A total of 531 newly admitted undergraduate students were recruited for this survey in the first quarter of 2016 (January to March, 2016). CALDOSE_X 5.0 software was used to compute the Entrance Surface Dose (ESD) and Effective Dose (ED); while the Statistical Package for Social Sciences (SPSS) version 21.0 was used to carry out the statistical analyses. The basic patients' data and exposure parameters required for the software are age, sex, examination type, projection posture, tube potential and current-time product. The mean Entrance Surface Dose and Effective Doses of the undergraduate students were calculated using the software, and the values were compared with existing literature and internationally established diagnostic reference levels. The mean ESD calculated is 0.29 mGy, and the mean effective dose is 0.04 mSv. The values of ESD and ED obtained are below the internationally established diagnostic reference levels, which could be attributed to good radiographic techniques employed during the chest X-ray procedure for these students.

Keywords: x-ray, dose, examination, chest

Procedia PDF Downloads 164

Authors: Muhammad Umar Hassan

Abstract:

Renal cell carcinoma is a subset of kidney cancer that arises in the lining of DCT and is present in parenchymal tissue. Diagnosis is based on lab reports, including urinalysis, renal function tests (RFTs), and electrolyte balance, along with imaging techniques. Organ failure and other complications have been commonly observed in these cases. Over the years, the presentation of patients has varied, so carcinoma was classified on the basis of site, shape, and consistency for detailed analysis. Lifestyle patterns and occupational history were inquired about and recorded. Methods: Data from 100 patients presenting to the oncology and nephrology department of Mayo Hospital in the year 2015-2020 were included in this retrospective study on a random basis. The study was specifically focused on three risk factors. Smoking, occupational exposures, and Hakim medicine are taken by the patient for any cause. After procurement of data, follow-up contacts of these patients were established, resulting in a detailed analysis of lifestyle. Conclusion: The inference drawn is a direct causal link between smoking, industrial workplace exposure, and Hakim medicine with the development of Renal Cell Carcinoma. It was shown in the majority of the patients and hence confirmed our hypothesis.

Keywords: renal cell carcinoma, kidney cancer, clear cell carcinoma

Procedia PDF Downloads 82

Authors: Zakheleni P. Dube, Phatu W. Mashela

Abstract:

The Curve-fitting Allelochemical Response Data (CARD) model had been adopted as a valuable tool in enhancing the understanding of the efficacy of cucurbitacin-containing phytonematicides on the suppression of nematodes. In most cases, for registration purposes, the active ingredients should be in purified form. Evidence in other phytonematicides suggested that purified active ingredients were less effective in suppression of nematodes. The objective of this study was to use CARD model to compare the overall sensitivities of Meloidogyne incognita J2 hatch, mobility and mortality to Nemarioc-AL phytonematicides, cucurbitacin A, Nemafric-BL phytonematicide and cucurbitacin B. Meloidogyne incognita eggs and J2 were exposed to 0.00, 0.50, 1.00, 1.50, 2.00, 2.50, 3.00, 3.50, 4.00, 4.50 and 5.00% of each phytonematicide, whereas in purified form the concentrations were 0.00, 0.25, 0.50, 0.75, 1.00, 1.25, 1.50, 1.75, 2.00, 2.25 and 2.50 μg.mL⁻¹. The exposure period to each concentration was 24-, 48- and 72-h. The overall sensitivities of J2 hatch to Nemarioc-AL phytonematicide, cucurbitacin A, Nemafric-BL phytonematicide and cucurbitacin B were 1, 30, 5 and 2 units, respectively, whereas J2 mobiltity were 3, 17, 3 and 6 units, respectively. For J2 mortality overall sensitivities to Nemarioc-AL phytonematicide, cucurbitacin A, Nemafric-BL phytonematicide and cucurbitacin B were 2, 4, 1 and 4 units, respectively. In conclusion, the two crude extracts, Nemarioc-AL and Nemafric-BL phytonematicides were generally more potent to M. incognita compared to their pure active ingredients. The crude plant extract preparation is easy, and they could be an ideal tactic for the management of nematodes in resource poor farming communities.

Keywords: Botanicals, cucumin, leptodermin, plant extracts, triterpenoids

Procedia PDF Downloads 198

Authors: Thirumila Muthukamaru

Abstract:

The objective of a Health Risk Assessment (HRA) is to achieve a quality evaluation of risk assessments in a timely manner where adequate controls can be in place to protect workers health, especially during turnarounds where the exposure to health hazards is expected to rise during the performance of the many activities that take place, exposing workers to health risk. HRA development requires a competent team comprising experienced subject matter experts in the field, such as Industrial hygienists, Occupational Health Doctors, Turnaround Coordinators, Operation / Maintenance personnel, etc. The conventional way of conducting HRA is not only tedious and time-consuming but also less appreciated when it is not interpreted correctly, which may contribute to inadequate operationalization of it. Simplification can be the essence of timely intervention in managing health risks. This paper is intended as a sharing of the approach taken to simplify the methodology of developing the HRA report and operationalizing it. The approach includes developing a Generic HRA for turnaround activities to be used as a reference document and the empowerment of identified personnel through upskilling sessions to take up the role of facilitating HRA sessions. This empowerment is one of the key approaches towards the successful translation of the HRA into specific turnaround Job Hazard Analysis (JHA) that embed it in the Permit to Work (PTW) process. The approach used here increases awareness and compliance on HRA for turnaround activities through better interpretation and operationalization of the HRA report, adding value to the risk assessment for turnaround activities.

Keywords: industrial hygiene, health risk assessment, HRA, risk assessment

Procedia PDF Downloads 27

Authors: Ali Olfati, Parichehr Nouri

Abstract:

Objective: In this study, we have investigated for the first time in the literature the efficacy of riboflavin [VB2] in preventing uterus As₂O₃ damage. Methods: Rats received 40 μg LHRHa for estrus synchronization. 48 pregnant Wistar rats were included. Four groups were formed with 7 rats in each group: Sham, 1.5 mg arsenic trioxide (As₂O₃/L) alone or in combination with VB2 [20 and 40 mg/L] in drinking water [for 21 days continuously]. Similar to maternal generation treatment, the F1-female generation was also arranged [for 35 days continuously until puberty]. Results: Data indicated that As₂O₃ reduced body weight and feed intake (p<0.05). Furthermore, the serum malondialdehyde levels in the As₂O₃ group were significantly higher than that of the control group (p<0.05). At the same time, total antioxidative status and the activities of glutathione peroxidase, superoxide dismutase, and catalase were reduced (p<0.05). Meanwhile, As₂O₃ remarkably increased the production of inflammatory markers [interleukin 6 and C-reactive protein](p<0.05). As₂O₃ administration induced uterus apoptosis-related genes by upregulating caspase-3, iNOS, and Bax genes and downregulating Bcl-2 gene of pubertal F1-female rats (p<0.05). Conclusion: Our observation indicated that VB2 therapy is potentially an effective strategy to modifying the detrimental effects of As₂O₃ in pubertal F1-female rats via suppresses oxidative damages.

Keywords: As₂O₃, inflammation, puberty, vitamin B2

Procedia PDF Downloads 129

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

Abstract:

Suppressors of cytokine signalling (SOCS3), a newly indentified anti-apoptotic molecule is a downstream effecter of the receptor tyrosine kinase-Ras signalling pathway. Current study has uncovered that SOCS3 may have wide and imperative capacities, particularly because of its close correlation with malignant tumors. To investigate the impact of SOCS3 on MDR, we analyzed the expression of P-gp and SOCS3 by immune-histochemistry and found there was positive correlation between them. At that point we effectively interfered with RNA translation by the contamination of siRNA of SOCS3 into MCF7/ADM breast cancer cell lines through a lentivirus, and the expression of the target gene was significantly inhibited. After RNAi the drug resistance was reduced altogether and the expression of MDR1 mRNA and P-gp in MCF7/ADM cell lines demonstrated a significant decrease. Likewise the expression of P53 protein increased in a statistically significant manner (p ≤ 0.01) after RNAi exposure. Moreover, flowcytometry analysis uncovers that cell cycle and anti-apoptotic enhancing capacity of cells changed after RNAi treatment. These outcomes proposed SOCS3 may take part in breast cancer MDR by managing MDR1 and P53 expression, changing cell cycle and enhancing the anti-apoptotic ability.

Keywords: SOCS3gene, breast cancer, multidrug resistance, MDR1 gene, RNA interference

Procedia PDF Downloads 321

Authors: Job Bapyibi Guyson, Bangripa Kefas

Abstract:

The advent of social media has no doubt provided platforms that facilitate the spread of fake news. The devastating impact of this does not only end with the prevalence of rumours and propaganda but also poses potential impact on individuals’ mental well-being. Therefore, this study on examining the impact of fake news on the mental health of residents in Jos metropolis among others interrogates the impact of exposure to fake news on residents' mental health. Anchored on the Cultivation Theory, the study adopted quantitative method and surveyed two the opinions of hundred (200) social media users in Jos metropolis using purposive sampling technique. The findings reveal that a significant majority of respondents perceive fake news as highly prevalent on social media, with associated feelings of anxiety and stress. The majority of the respondents express confidence in identifying fake news, though a notable proportion lacks such confidence. Strategies for managing the mental impact of encountering fake news include ignoring it, fact checking, discussing with others, reporting to platforms, and seeking professional support. Based on these insights, recommendations were proposed to address the challenges posed by fake news. These include promoting media literacy, integrating fact-checking tools, adjusting algorithms and fostering digital well-being features among others.

Keywords: fake news, mental health, social media, impact

Procedia PDF Downloads 24

Authors: Adel Omar Ashour, Paul S. Dyer

Abstract:

Aspergillus nidulans can reproduce by asexual or sexual means, producing green conidiospores or red-purple ascospores respectively. The latter one is produced in dark-purple globose ‘cleistothecia’ which are surrounded by Hülle cells. The species has a homothallic (self fertile) sexual breeding system. Given the extra metabolic costs associated with sexual compared to asexual reproduction it would be predicted that ascospore production would confer evolutionary benefits. However, due to the homothallic breeding system there is very rarely any increased genetic variation in ascospore offspring and traditionally conidia and ascospores are considered to be equally environmental resistant. We therefore examined in detail whether conidia and ascospores might exhibit as yet undetected differences in spore viability when subjected to certain environmental stressors. Spores from two strains of A. nidulans (comprising wild-type and KU mutants) were exposed to various levels of temperature (50-70°C for 30 min) and UV (350 nm for 10-60 min) stress. Results of experiments will be presented, including comparison of ‘D’ (decimal point reduction) values of conidia versus ascospores of A. nidulans. We detected that under certain exposure levels ascospores have significantly increased resistance compared to conidia. The increased environmental resistance of ascospores might be a key factor explaining the persistence of sexuality in this homothallic species, and reasons for differential survival are suggested.

Keywords: Aspergillus nidulans, asexual reproduction, conidia, ascospores, cleistothecia, d-value

Procedia PDF Downloads 341

Authors: Azhar Jabareen, Mahmoud Huleihel

Abstract:

BRCA-1 is a multifunctional tumor suppressor, whose expression is activated by the estrogen (E2)-liganded ERα receptor. The activated ERα is a transcriptional factor which activates various genes either by direct binding to the DNA at E2-responsive elements (EREs) and indirectly associated with a range of alternative non-ERE elements. Interference with BRCA-1 expression and/or functions leads to high risk of breast or/and ovarian cancer. Our lab investigated the involvement of Human T-cell leukemia Virus Type 1 (HTLV-1) in breast cancer, since HTLV-1 Tax was found to strongly inhibit BRCA-1 expression. In addition, long exposure of 12-O-tetradecanoylphorbol-13-acetate (TPA), which is one of the stress-inducing agents activated the HTLV-1 promoter. So here the involvement of TPA in breast cancer had been examined by testing the effect of TPA on BRCA-1 and ERE expression. The results showed that TPA activated both BRCA-1 and ERE expression. In the 12 hours TPA activated the tow promoters more than others time, and after 24 hours the level of the tow promoters was decreased. Tax inhibited BRCA-1 expression but did not succeed to inhibit the effect of TPA. Then the activation of the two promoters was not through ERα pathway because TPA had no effect on ERα binding to the two promoters of the BRCA-1 and ERE. Also, the activation was not via nuclear factor kappa B (NF-κB) pathway because when the inhibitory of NF-κB had been added to the TPA, it still activated the tow promoters. However, it seems that 53BP1 may be involved in TPA activation of these promoters because ectopic high expression of 53BP1 significantly reduced the TPA activity. In addition, in the presence of Bisindolylmaleimide-I (BI)- the inhibitor of Protein Kinase C (PKC)- there was no activation for the two promoters, so the PKC is agonized BRCA-1 and ERE activation.

Keywords: BRCA-1, ERE, HTLV-1, TPA

Procedia PDF Downloads 230

Authors: Hoda Aleali, Nastran Mansour, Maryam Mirzaie

Abstract:

In this paper, we study the optical nonlinearities of Silver sulfide (Ag2S) nanostructures dispersed in the Dimethyl sulfoxide (DMSO) under exposure to 532 nm, 15 nanosecond (ns) pulsed laser irradiation. Ultraviolet–visible absorption spectrometry (UV-Vis), X-ray diffraction (XRD), and transmission electron microscopy (TEM) are used to characterize the obtained nanocrystal samples. The band gap energy of colloid is determined by analyzing the UV–Vis absorption spectra of the Ag2S NPs using the band theory of semiconductors. Z-scan technique is used to characterize the optical nonlinear properties of the Ag2S nanoparticles (NPs). Large enhancement of two photon absorption effect is observed with increase in concentration of the Ag2S nanoparticles using open Z-scan measurements in the ns laser regime. The values of the nonlinear absorption coefficients are determined based on the local nonlinear responses including two photon absorption. The observed aperture dependence of the Ag2S NP limiting performance indicates that the nonlinear scattering plays an important role in the limiting action of the sample.The concentration dependence of the optical liming is also investigated. Our results demonstrate that the optical limiting threshold decreases with increasing the silver sulfide NPs in DMSO.

Keywords: nanoscale materials, silver sulfide nanoparticles, nonlinear absorption, nonlinear scattering, optical limiting

Procedia PDF Downloads 377

Authors: Mitra Mesgar

Abstract:

Online learning environment is becoming more popular among learners because of their multiple information representations. Despite the growing importance of online reading strategies among adult learners, little attention has been carried out to postgraduate EFL learners. This study is quantitative research designed and aimed to investigate metacognitive reading strategies employed by Iranian postgraduate learners to read online academic texts. This study is conducted by over 50 Iranian postgraduate students studying in different Malaysian universities. This study used two different survey questionnaires, namely, 1) background questionnaire and 2) OSORS questionnaire. The collected data were analyzed using SPSS. The findings of the study emphasized metacognitive reading strategies used by different aged adult learners. The results of the survey questionnaires revealed that adult learners use global reading strategies as well as problem-solving strategies and support reading strategies. Also, through one-way analysis of variance toward age factor revealed that it has no meaningful changes on metacognitive reading strategy usage. This means that metacognitive reading strategies used by adult learners are independent of age variable. Drawing from findings, adult learners have learning goals, and since they have more exposure to online academic texts, they are able to use different metacognitive online reading strategies that affect their understanding of academic texts.

Keywords: online reading strategies, metacognitive strategies, online learning, independent students, locus of control

Procedia PDF Downloads 72

Authors: Elham Ahmadi, Mehrdad Ravanshad, Joyce Fingeroth, Mazyar Ziyaeyan, Rajesh Panigrahi, Jun Xie, Gao Guangping

Abstract:

B-cell proliferative disorders often occur among persons that are T-cell compromised. These disorders are primarily EBV+ and can first present with a focal lesion. Direct introduction of oncolytic viruses into localized tumors provides theoretical advantages over chemotherapy and immunotherapy by reducing systemic toxicity, to which the immunocompromised host is most vulnerable. Widely studied as a vehicle for gene therapy, AAV has only rarely been applied to treat cancer. As a prelude to development of a therapeutic vehicle, we assessed the ability of 15 distinct recombinant AAV serotypes (rAAV1, rAAV2, rAAV3b, rAAV4, rAAV5, rAAV6, rAAV6.2, rAAV6TM, rAAV7, rAAV8, rAAVrh8, rAAV9, rAAVrh10, rAAV39, rAAV43) bearing eGFP to infect human B-cell tumor lines compared with primary B-cells in vitro. Enhanced infection of tumor lines by AAV 6.2 was demonstrated by flow cytometry. EBV superinfection of EBV negative B-cell tumor lines increased susceptibility to AAV6.2 infection. As proof of concept, AAV6.2 bearing HSV-1 thymidine kinase in place of eGFP eliminated tumor cells upon exposure to ganciclovir.

Keywords: AAV, gene therapy, lymphoma, malignancy, tropism

Procedia PDF Downloads 97

Authors: Chung-Hao Wu, Tung-Dju Lin, Ming-Chin Ho, Minehiro Nishiyama

Abstract:

This paper discusses reported fire tests of concrete beams and columns, future fire tests of beam/column frames, and an innovative concept for designing a beam/column furnace. The proposed furnace could be designed to maximize the efficiency of fire test procedures and minimize the cost of furnace construction and fuel consumption. ASTM E119 and ISO 834 standards were drafted based on prescriptive codes and have several weaknesses. The first involves a provision allowing the support regions of a test element to be protected from fire exposure. The second deals with the L/30 deflection end point instead of the structural end point (collapse) in order to protect the hydraulic rams from fire damage. Furthermore, designers commonly use the measured fire endurances of interior columns to assess fire ratings of edge and corner columns of the same building. The validity of such an engineering practice is theoretically unsound. Performance-Based Codes (PBC) require verification tests of structural frames including the beam/column joints to overcome these weaknesses but allow the use of element test data as reference only. In the last 30 years, PBC have gained global popularity because the innovative design and flexibility in achieving an ultimate performance goal.

Keywords: fire resistance, concrete structure, beam/column frame, fire tests

Procedia PDF Downloads 311

Authors: Alev Atak

Abstract:

In this paper, we aim to create a financial sentiment index by investigating the company’s voluntary information disclosures. We retrieve structured content from BIST 100 companies’ financial reports for the period 1998-2018 and extract relevant financial information for sentiment analysis through Natural Language Processing. We measure strategy-related disclosures and their cross-sectional variation and classify report content into generic sections using synonym lists divided into four main categories according to their liquidity risk profile, risk positions, intra-annual information, and exposure to risk. We use Word Error Rate and Cosin Similarity for comparing and measuring text similarity and derivation in sets of texts. In addition to performing text extraction, we will provide a range of text analysis options, such as the readability metrics, word counts using pre-determined lists (e.g., forward-looking, uncertainty, tone, etc.), and comparison with reference corpus (word, parts of speech and semantic level). Therefore, we create an adequate analytical tool and a financial dictionary to depict the importance of granular financial disclosure for investors to identify correctly the risk-taking behavior and hence make the aggregated effects traceable.

Keywords: financial sentiment, machine learning, information disclosure, risk

Procedia PDF Downloads 82

Authors: Fatma H. Galal, Alaaeddeen M. Seufi

Abstract:

Due to the increasing usage of mobile phone, experiments were designed to investigate ‎the effect of acute dose exposure on the mosquito life cycle. 50 tubes (5 ml size) ‎containing 3 ml water and a first instar larva of the mosquito, Culex univittatus were put ‎between two mobile cell phones switched on talking mode for 4 continuous hours. A ‎control group of tubes (unexposed to radiation) were used. Larval and pupal durations ‎were calculated. Furthermore, adult emergence and sex ratio were observed for both ‎treated and control larvae. Results indicated that the employed dose of radiation reduced ‎total larval duration to about half the value of control. 1st, 2nd, 3rd and 4th larval ‎durations were reduced significantly by mobile radiation when compared to controls. ‎Meanwhile pupal duration was elongated significantly by mobile radiation when ‎compared to control. Sex ratio was significantly shifted in favor of females in the case of ‎radiated mosquitoes. Successful adult emergence was decreased significantly in the case ‎of radiated insects when compared to controls. Molecular studies to investigate the ‎effects of mobile radiation on insects and other model organisms are going on.‎

Keywords: mosquito, mobilr radiation, larval and pupal durations, sex ratio

Procedia PDF Downloads 169

Authors: T. O. Adekunle, R. L. Makhubu, C. N. Ngwane

Abstract:

This research was designed to assess the validity of the Sapir Whorf hypothesis in relation to the linguistic and cultural notions of the Yoruba and Zulu language speakers’ via the evaluation of the culture enriched dramatic text The Lion and The Jewel by Wole Soyinka. The study queried both the hypothesis’ strong version, (language governs thought: linguistic classifications restrain and influence mental classifications); and its weak version, (linguistic classifications and their use influence thought as well as some other classes of non-linguistic activities) and their possible reliability. Participants were purposively selected and their ages ranged from 16-46 years old. The participants amounted to 38 (18 Yoruba and 20 Zulu) students of DUT who all speak both English and Zulu (Zulu participants) and English and Yoruba (Yoruba participants) and the mixed methods approach was used. Thus with the use of questionnaire and interviews the research questions were answered and the findings provided support for validity of the linguistic relativity hypothesis, languages indeed influence thought. The findings also revealed that linguistic influence on cognition is not limited to different language users alone, but also same language speakers per level of exposure to other languages and concepts.

Keywords: culture, cognition, DUT, language, linguistic relativity hypothesis, Sapir-Whorf hypothesis, The Lion and The Jewel, thought, Wole Soyinka, Yoruba, Zulu

Procedia PDF Downloads 437

Authors: Zahra Tolou-Ghamari

Abstract:

Introduction: After allogeneic organ transplantation, in order to lower the rate of rejectiontacrolimus is given. In fact, infection is reported as the most complication of tacrolimus that might be associated with higher susceptibility by its’ long term use. Aim: This study aims to review the association between the occurrence of infections after organ transplantation following the administration of tacrolims. Materials and Methods: Scientific literature on the pharmacotherapy of tacrolimus after organ transplantation and infections were searched using PUBMED.Gov (https://pubmed.ncbi.nlm.nih.gov/), Web of Science, and Scopus. Results: In order to prevent acute and chronic rejection, the potent immunosuppressive drug tacrolimus administered as a calcineurin inhibitor after organ transplantation. Its’ most frequent infectious complication is reported as urinary tract infection. Virulent strain of recombinant Literiamonocytogenes, in addition to an increase in bacterial burden in the liver and spleen tissues, was reported in the animal experimental study. The consequence of aggressive events and recipients total area under the cureve exposure to immunosuppressive could be as considered as surrogate markers for individual infection’s risk evaluation. Conclusion: Transplant surgery and duration of hospital stay could determinate the risk of infection during the first month of organ transplantation. Despite administration of antiviral drugs, opportunistic infection such as cytomegalovirus could increase the risk of infection during month 1 to year after transplantation.

Keywords: transplant, infection, tacrolimus, kidney

Procedia PDF Downloads 104

Authors: A. Pontrandolfi, G. Enjolras, F. Capitanio

Abstract:

The study analyses the strategies Italian farmers use to cope with the risks that face their production. We specifically explore the potential and the limitations of the economic tools for climatic risk management in agriculture of the Common Agricultural Policy 2014-2020, that foresees contributions for economic tools for risk management, in relation to farms’ needs, exposure and vulnerability of agricultural areas to climatic risk. We consider at the farm level approaches to hedge risks in terms of the use of technical tools (agricultural practices, pesticides, fertilizers, irrigation) and economic/financial instruments (insurances, etc.). We develop cross-sectional and longitudinal analyses as well as analyses of correlation that underline the main differences between the way farms adapt their structure and management towards risk. The results show a preference for technical tools, despite the presence of important public aids on economic tools such as insurances. Therefore, there is a strong need for a more effective and integrated risk management policy scheme. Synergies between economic tools and risk reduction actions of a more technical, structural and management nature (production diversification, irrigation infrastructures, technological and management innovations and formation-information-consultancy, etc.) are emphasized.

Keywords: agriculture and climate change, climatic risk management, insurance schemes, farmers' approaches to risk management

Procedia PDF Downloads 321

Authors: Nihal Abdel Hamid Taha

Abstract:

Crack evaluation of flexure reinforced concrete (RC) member is considered an important step in the design process, since the formation of concrete cracks depends on the possibility of exposure to various conditions(pollution, humidity,..etc.). Because of the disparity between different grades of steel in the service load stresses, this affects the cracking behavior. This paper is concerned with the crack pattern and cracking load for concrete beams with T-section reinforced with two different grades of steel at the service load levels stages up to ultimate load. A practical program has been put up to investigate the difference between reinforced steel bars with yield strength 420 N/mm2 and 500 N/mm2 through six T-section reinforced beams. The beams were tested under static- monotonic two– point service loading up to ultimate failure under flexural stresses. The influence of parameters such as clear concrete cover and concrete compressive strength are considered for each of the two grades of steel used. Cracking load, spacing and width were determined. The experimental results demonstrated that increasing the concrete strength results in both of cracking and ultimate load increase, while no significant difference in yield load for the two steel grades used. It has also become obvious, that the number of cracks was more for the lower steel strength, which is followed by decrease in crack width and spacing.

Keywords: RC beams, cracking behavior, steel stress, crack width, crack spacing

Procedia PDF Downloads 40

Authors: Salwa Hagag Abdelaziz, Dorria Salem, Hoda Zaki, Suzan Atteya

Abstract:

Early detection of breast cancer saves many thousands of lives each year via application of mammography and genetic screening and many more lives could be saved if nurses are involved in breast care screening practices. So, the aim of the study was to identify nurse's role in early detection of breast cancer through mammography and genetic screening and its impact on patient's outcome. In order to achieve this aim, 400 women above 40 years, asymptomatic were recruited for mammography and genetic screening. In addition, 50 nurses and 6 technologists were involved in the study. A descriptive analytical design was used. Five tools were utilized: sociodemographic, mammographic examination and risk factors, women's before, during and after mammography, items relaying to technologists, and items related to nurses were also obtained. The study finding revealed that 3% of women detected for malignancy and 7.25% for fibroadenoma. Statistically, significant differences were found between mammography results and age, family history, genetic screening, exposure to smoke, and using contraceptive pills. Nurses have insufficient knowledge about screening tests. Based on these findings the present study recommended involvement of nurses in breast care which is very important to in force population about screening practices.

Keywords: mammography, early detection, genetic screening, breast cancer

Procedia PDF Downloads 547

Authors: Ira Slabodar

Abstract:

Autonomous learning in English as a Foreign Language (EFL) refers to the use of target language, learner collaboration and students’ responsibility for their learning. Teachers play a vital role of mediators and facilitators in self-regulated method. Thus, their perception of self-guided practices dictates their implementation of this approach. While research has predominantly focused on inadequate administration of autonomous learning in school mostly due to lack of appropriate teacher training, this study examined whether novice teachers who were exposed to extensive autonomous practices were likely to implement this method in their teaching. Twelve novice teachers were interviewed to examine their perception of learner autonomy and their administration of this method. It was found that three-thirds of the respondents experienced a gap between familiarity with autonomous learning and a favorable attitude to this approach and their deficient integration of self-directed learning. Although learner-related and institution-oriented factors played a role in this gap, it was mostly caused by the respondents’ not being genuinely autonomous. This may be due to indirect exposure rather than explicit introduction of the learner autonomy approach. The insights of this research may assist curriculum designers and heads of teacher training programs to rethink course composition to guarantee the transfer of methodologies into EFL classes.

Keywords: learner autonomy, teacher training, english as a foreign language (efl), genuinely autonomous teachers, explicit instruction, self-determination theory

Procedia PDF Downloads 39

Authors: Zikora K. G. Anyaegbunam, Annabel A. Nnawuihe, Ngozi J. Anyaegbunam, Emmanuel A. Eze

Abstract:

The discovery and production of new antibiotics is unavoidable in the fight against drug-resistant bacteria. However, this is only part of the problem; we have never really had medications that could completely eradicate an infection. All pathogens create a limited number of dormant persister cells that are resistant to antibiotic treatment. When the concentration of antibiotics decreases, surviving persisters repopulate the population, resulting in a recurrent chronic infection. Bacterial populations have an alternative survival strategy to withstand harsh conditions or antibiotic exposure, in addition to the well-known methods of antibiotic resistance and biofilm formation. Persister cells are a limited subset of transiently antibiotic-tolerant phenotypic variations capable of surviving high-dose antibiotic therapy. Persisters that flip back to a normal phenotype can restart growth when antibiotic pressure drops, assuring the bacterial population's survival. Persister cells have been found in every major pathogen, and they play a role in antibiotic tolerance in biofilms as well as the recalcitrance of chronic infections. Persister cells has been implicated to play a role in the establishment of antibiotic resistance, according to growing research. Thusthe need to basically elucidate the biology of persisters and how they are linked to antibiotic resistance, and as well it's link to diseases.

Keywords: persister cells, phenotypic variations, repopulation, mobile genetic transfers, antibiotic resistance

Procedia PDF Downloads 186

Authors: Jeffrey Cacho, Sherwin Reyes

Abstract:

The research targeted enhancing energy utilization and reducing waste in roasting processes, particularly in Camarines Norte, where Bounty Agro Ventures Incorporated dominates through brands such as Chooks-to-Go, Uling Roaster, and Reyal. Competitors like Andok’s and Baliwag Lechon Manok also share the market. A staggering 90% of these businesses use traditional glass-type roasting furnaces fueled by wood charcoal, leading to significant energy loss and inefficiency due to suboptimal heat conservation. Only a mere 10% employ electric ovens. Many available furnaces, typically constructed from industrial materials through welding and other metal joining techniques, are not energy-efficient. Cost-prohibitive commercial options compel some micro-enterprises to fabricate their furnaces. The study proposed developing an eco-friendly, cost-effective roasting furnace with excellent heat retention. The distinct design aimed to reduce cooks' heat exposure and overall fuel consumption. The furnace features an angle bar frame, a combustion chute for fuel burning, a heat-retaining clay-walled chamber, and a top cover, all contributing to improved energy savings and user safety.

Keywords: biomass roasting furnace, heat storage, combustion chute, start-up roasting business

Procedia PDF Downloads 30

Authors: Sijia Hu

Abstract:

Tensile creep tests were performed along the normal direction on the as-solutioned (AS) and as-aged (AA) samples of a commercial ZK60 alloy in this work. The results showed that the AA sample obtained a stronger 0.2% proof stress but a poorer creep resistance in comparison to the AS sample. It was revealed that the creep deformation in the AS sample was attributed to basal slip and twinning, while the creep behavior of the AA sample was controlled by basal slip, pyramidal slip and twinning. Besides, the reasons for the poorer creep resistance of the AA sample were unveiled. Pyramidal dislocations towards various moving directions were found to accelerate the creep deformation, and basal dislocations kinking at twin boundaries were found to induce heavy stress concentration. Furthermore, massive dynamic precipitates, including beta 1 prime and beta 2 prime types, were formed in the AS sample during the creep exposure, contributing to the superior creep resistance. But in the AA sample, plentiful beta 1 prime and beta 2 prime phases generated during the prior peak-aging treatment dissolved into the matrix fast and only beta 1 prime re-precipitated during the creep process. With the decreased area fractions of precipitates, the age-hardening effect slacked off and failed to enhance the creep resistance.

Keywords: Mg alloy, creep, precipitation, microstructure

Procedia PDF Downloads 16