Search results for: primary defects

Authors: Alberto Fina, Samuele Colonna, Maria del Mar Bernal, Orietta Monticelli, Mauro Tortello, Renato Gonnelli, Julio Gomez, Chiara Novara, Guido Saracco

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Thermally conductive polymer nanocomposites are of high interest for several applications including low-temperature heat recovery, heat exchangers in a corrosive environment and heat management in electronics and flexible electronics. In this paper, the preparation of thermally conductive nanocomposites exploiting graphene-related materials is addressed, along with their thermal characterization. In particular, correlations between 1- chemical and physical features of the nanoflakes and 2- processing conditions with the heat conduction properties of nanocomposites is studied. Polymers are heat insulators; therefore, the inclusion of conductive particles is the typical solution to obtain a sufficient thermal conductivity. In addition to traditional microparticles such as graphite and ceramics, several nanoparticles have been proposed, including carbon nanotubes and graphene, for the use in polymer nanocomposites. Indeed, thermal conductivities for both carbon nanotubes and graphenes were reported in the wide range of about 1500 to 6000 W/mK, despite such property may decrease dramatically as a function of the size, number of layers, the density of topological defects, re-hybridization defects as well as on the presence of impurities. Different synthetic techniques have been developed, including mechanical cleavage of graphite, epitaxial growth on SiC, chemical vapor deposition, and liquid phase exfoliation. However, the industrial scale-up of graphene, defined as an individual, single-atom-thick sheet of hexagonally arranged sp2-bonded carbons still remains very challenging. For large scale bulk applications in polymer nanocomposites, some graphene-related materials such as multilayer graphenes (MLG), reduced graphene oxide (rGO) or graphite nanoplatelets (GNP) are currently the most interesting graphene-based materials. In this paper, different types of graphene-related materials were characterized for their chemical/physical as well as for thermal properties of individual flakes. Two selected rGOs were annealed at 1700°C in vacuum for 1 h to reduce defectiveness of the carbon structure. Thermal conductivity increase of individual GNP with annealing was assessed via scanning thermal microscopy. Graphene nano papers were prepared from both conventional RGO and annealed RGO flakes. Characterization of the nanopapers evidenced a five-fold increase in the thermal diffusivity on the nano paper plane for annealed nanoflakes, compared to pristine ones, demonstrating the importance of structural defectiveness reduction to maximize the heat dissipation performance. Both pristine and annealed RGO were used to prepare polymer nanocomposites, by melt reactive extrusion. Thermal conductivity showed two- to three-fold increase in the thermal conductivity of the nanocomposite was observed for high temperature treated RGO compared to untreated RGO, evidencing the importance of using low defectivity nanoflakes. Furthermore, the study of different processing paremeters (time, temperature, shear rate) during the preparation of poly (butylene terephthalate) nanocomposites evidenced a clear correlation with the dispersion and fragmentation of the GNP nanoflakes; which in turn affected the thermal conductivity performance. Thermal conductivity of about 1.7 W/mK, i.e. one order of magnitude higher than for pristine polymer, was obtained with 10%wt of annealed GNPs, which is in line with state of the art nanocomposites prepared by more complex and less upscalable in situ polymerization processes.

Keywords: graphene, graphene-related materials, scanning thermal microscopy, thermally conductive polymer nanocomposites

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Authors: B. Nair, S. Singh

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Oral health behaviors such as dietary preferences and tooth brushing are acquired during a child’s primary socialization period yet many oral health promotion interventions are implemented without taking into account the role and impact of parental influence in supporting healthy oral health behaviors. The aim and objective of this study was to determine the relationship between parental income and level of education with knowledge, attitudes and perceptions of oral health care practices. Methods: The study design was cross-sectional and exploratory, and data collection occurred in two phases. Phase 1 comprised of a self-administered questionnaire. The sample consisted of parents of 313 Grade 1 learners aged between 5-6 years old attending one of twelve selected public primary schools in the Chatsworth Circuit, Durban, South Africa. Phase 2 comprised of focus group discussions held at 5 purposively selected schools. Data collection comprised of a semi-structured face-to-face group interview with the objective of obtaining a deeper understanding of parental knowledge, attitudes and perceptions of dental caries. Results and Discussion: Almost 56% of participants earned a monthly income of less than R6000 (600 US dollars). Nearly three quarters (77.5%) of participants indicated that they did not have medical aid/insurance scheme. More than three-quarters of the participants (76.6%) identified diet as being the primary cause of decayed teeth. More than half of the study sample (56.1%) indicated that milk teeth were important and that rotten teeth (74.6%) could affect the child’s health. Almost half (49.8%) of participants reported that “bad teeth” were inherited. With more than two-thirds of the participants (77.7%), having at most a high school education, there was a correlation between the level of the caregiver’s education and the oral health care of the child. The analysis of the correlation between a child having decayed teeth and income (p=.007); and the manner in which the income is received (p=.003) was statistically significant. The results indicate that more effort needs to be placed in understanding parental knowledge, perceptions and attitudes towards dental caries. Parental level of education, income and oral health literacy is shown to be related to attitudes, and perceptions towards dental caries and its subsequent preventive measures. These findings have important implications for oral health planning at community and facility-based levels.

Keywords: oral health prevention, parental education, dental caries, attitudes and perceptions

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Authors: Harish Aryal, Thalia Balderas, Alondra Rodriguez

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Radioactivity present in nature possess a major challenge to public health and occupational concerns. Even at low doses, NORM can cause radiation-induced cancers, heritable diseases, genetic defects, etc. There have not been enough radiological studies and consequently, there is a lack of supportive data. In addition, there is no universal medical surveillance program for low-level doses and there is a need for NORM management guidelines for appropriate control. Naturally Occurring Radioactive Material (NORM) is present everywhere during oil/gas exploration. Currently, there is limited data available to quantify radioactivity. This research presents the study of radioactivity in different areas in the United States to be encouraged to be used for further study in Texas or similar areas within the oil and gas industry. Many materials that are found in the oil and gas industry are NORM (Naturally Occurring Radioactive Materials). The NORM is made of various types of materials, including Radium 226, Radium 228, and Radon 222. Efforts to characterize the geographic distribution of NORM have been limited by poor statistical representation in this area of study. In addition, the fate of NORM in the environment has not been fully defined, and few human health risk assessments have been conducted. To further comprehend how to measure radioactivity in oil and gas, it will be essential to understand the amount and type of radioactivity that is wasted on the water and soil of the industry.

Keywords: NORM, radium 226, radon 222, radionuclides, geological formations

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Authors: Subodh Kumar, Ramkisan Pawar, Gopal D. Belurkar

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This paper describes a study for simple blanking tool. In blanking or piercing operation, punch and die should be concentric for proper cutting. In this study, tolerance analysis method is used to analyze the variation in the press tool assembly. Variation results into the eccentricity in between die and punch due to cumulative tolerance of parts used in assembly. 1D variation analysis were performed by CREO parametric computer aided design (CAD) Software Powered by CETOL 6σ computer aided tolerance analysis software. Use of CAD analysis software given the opportunity to find out the cause of variation in tool assembly. Accordingly, the new specification of tolerance and process setting for die set manufacturing has determined. Tolerance allocation and tolerance analysis method were performed iteratively to conclude that position tolerance as well as size tolerance of hole in top plate for bush and size tolerance of guide pillar were more responsible for eccentricity in punch and die. This work proposes optimum tolerance for press tool assembly parts to achieve 100 % yield for specified .015mm minimum tolerance zone.

Keywords: blanking, GD&T (Geometric Dimension and Tolerancing), DPMU (defects per million unit), press tool, stackup analysis, tolerance allocation, yield percentage

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Authors: Sheillah Hlamalani Mboweni, Lufuno Makhado

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Background: The increasing number of people who tested HIV positive and who demand antiretroviral therapy (ART) prompted the National Department of Health to adopt WHO recommendations of task shifting where Professional Nurses(PNs) initiate ART rather than doctors in the hospital. This resulted in the decentralization of services to primary health care(PHC), generating a need to capacitate PNs on NIMART. After years of training, the impact of NIMART was assessed where it was established that even though there was an increased number who accessed ART, the quality of care is of serious concern. The study aims to answer the following question: What are the challenges influencing NIMART implementation in primary health care. Objectives: This study explores challenges influencing NIMART training and implementation and makes recommendations to improve patient and HIV program outcomes. Methods: A qualitative explorative program evaluation research design. The study was conducted in the rural districts of North West province. Purposive sampling was used to sample PNs trained on NIMART. FGDs were used to collect data with 6-9 participants and data was analysed using ATLAS ti. Results: Five FGDs, n=28 PNs and three program managers were interviewed. The study results revealed two themes: inadequacy in NIMART training and the health care system challenges. Conclusion: The deficiency in NIMART training and health care system challenges is a public health concern as it compromises the quality of HIV management resulting in poor patients’ outcomes and retard the goal of ending the HIV epidemic. These should be dealt with decisively by all stakeholders. Recommendations: The national department of health should improve NIMART training and HIV management: standardization of NIMART training curriculum through the involvement of all relevant stakeholders skilled facilitators, the introduction of pre-service NIMART training in institutions of higher learning, support of PNs by district and program managers, plan on how to deal with the shortage of staff, negative attitude to ensure compliance to guidelines. There is a need to develop a conceptual framework that provides guidance and strengthens NIMART implementation in PHC facilities.

Keywords: antiretroviral therapy, nurse initiated management of retroviral therapy, primary health care, professional nurses

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Authors: Afshan Saad, Muhammad Saad, Shah Muhammad Emaduddin

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Bug reporting systems are most important tool that guides regarding different maintenance activities in software engineering. Duplicate bug reports which describe the bugs and issues in bug reporting system repository increases processing time of bug triage that monitors all such activities and software programmers who are working and spending time on reports which were assigned by triage. These reports can reveal imperfections and degrade software quality. As there is a number of the potential duplicate bug reports increases, the number of bug reports in bug repository increases. Identifying duplicate bug reports help in decreasing development work load in fixing defects. However, it is difficult to manually identify all possible duplicates because of the huge number of already reported bug reports. In this paper, an artificial intelligence based system using Mantis is proposed to automatically detect duplicate bug reports. When new bugs are submitted to repository triages will mark it with a tag. It will investigate that whether it is a duplicate of an existing bug report by matching or not. Reports with duplicate tags will be eliminated from the repository which not only will improve the performance of the system but can also save cost and effort waste on bug triage and finding the duplicate bug.

Keywords: bug tracking, triager, tool, quality assurance

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Authors: Yiying Xiao, Chia Wei Lim, Jinquan Chang, Qixin Yuan, Lei Wang, Ning Yan

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Electrocatalytic reductive amination (ERA) offers an attractive way to make organonitrogen chemicals from renewable feedstock. Here, we report carbon nanotube (CNT) as an effective catalyst for the ERA of biomass-derivable α-keto acids into amino acids using NH₃ as the nitrogen source. Through a facile ball milling (BM) treatment, the intrinsic defects in the CNTs were increased while the electrocatalytic activity of CNTs converting 2-ketoglutaric acid into glutamic acid was enhanced by approximately seven times. A high Faradaic efficiency (FE) of ~90% with a corresponding glutamic acid formation rate up to 180.9 mmol•g⁻¹𝒸ₐₜt•h⁻¹ was achieved, and ~60% molar yield of glutamic acid was obtained after 8 h of electrolysis. Electrokinetic analyses indicate that the BM-CNTs catalysed ERA exhibits first-order dependences on the substrate and NH₃, with a rate-determining step (RDS) involving the first electron transfer. Following this protocol, a number of amino acids were prepared with moderate to high FEs and formation rates. Significantly, we synthesised long carbon chain amino acids, which typically face lower yields using the existing methods.

Keywords: amino acids, carbon nanotubes, electrocatalysis, reductive amination, α-keto acids

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Authors: Hasan Taherkhani

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Increasingly accumulation of the solid waste materials has become a major environmental problem of communities. In addition to the protection of environment, the recycling and reusing of the waste materials are financially beneficial. Waste materials can be used in highway construction. This study aimed to investigate the applicability of recycled concrete, asphalt and steel slag powder, as a replacement of the primary mineral filler in asphalt concrete has been investigated. The primary natural siliceous aggregate filler, as control, has been replaced with the secondary recycled concrete, asphalt and steel slag powders, and some engineering properties of the mixtures have been evaluated. Marshal Stability, flow, indirect tensile strength, moisture damage, static creep and volumetric properties of the mixtures have been evaluated. The results show that, the Marshal Stability of the mixtures containing recycled powders is higher than that of the control mixture. The flow of the mixtures containing recycled steel slag is lower, and that of the mixtures containing recycled asphalt and cement concrete powder is found to be higher than that of the control mixture. It is also found that the resistance against moisture damage and permanent deformation of the mixture can be improved by replacing the natural filler with the recycled powders. The volumetric properties of the mixtures are not significantly influenced by replacing the natural filler with the recycled powders.

Keywords: filler, steel slag, recycled concrete, recycled asphalt concrete, tensile strength, moisture damage, creep

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Authors: Maheshwari Payal, Shapurkar Mayaan

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The present research aimed at studying the awareness and attitudes of teachers towards inclusive education. The sample consisted of 60 teachers, teaching in the primary section (1st – 4th) of regular schools affiliated to the SSC board in Mumbai. The sample was selected by Multi-stage cluster sampling technique. A semi-structured self-constructed interview schedule and a self-constructed attitude scale were used to study the awareness of teachers about disability and Inclusive education, and their attitudes towards inclusive education respectively. Themes were extracted from the interview data and quantitative data was analyzed using SPSS package. Results revealed that teachers had some amount of awareness but an inadequate amount of information on disabilities and inclusive education. Disability to most (37) teachers meant “an inability to do something”. The difference between disability and handicap was stated by most as former being cognitive while handicap being physical in nature. With regard to Inclusive education, a large number (46) stated that they were unaware of the term and did not know what it meant. The majority (52) of them perceived maximum challenges for themselves in an inclusive set up, and emphasized on the role of teacher training courses in the area of providing knowledge (49) and training in teaching methodology (53). Although, 83.3% of teachers held a moderately positive attitude towards inclusive education, a large percentage (61.6%) of participants felt that being in inclusive set up would be very challenging for both children with special needs and without special needs. Though, most (49) of the teachers stated that children with special needs should be educated in a regular classroom, but they further clarified that only those should be in a regular classroom who have physical impairments of mild or moderate degree.

Keywords: attitude, awareness, inclusive education, teachers

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Authors: Zaoiai Said, Makani Abdelkadir, Tafraoui Ahmed

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Concrete material suffers from a relatively low tensile strength and deformation capacity is limited. Such defects of the concrete are very fragile and sensitive to shrinkage cracking materials. The Self- Compacting Concrete (SCC) are highly fluid concretes whose implementation without vibration. This material replaces traditional vibrated concrete mainly seen techno-economic interest it presents. The SCC has several advantages which are at the origin of their development crunching. The research is therefore to conduct a comparison in terms of rheological and mechanical performance between different formulations to find the optimal dosage for rubber granulates. Through this research, we demonstrated that it is possible to make different settings SCC composition having good rheological and mechanical properties. This study also showed that the substitution of natural coarse aggregates (NA) by coarse rubber aggregates (RA) in the composition of the SCC, contributes to a slight variation of workability in the fresh state parameters still remaining in the field of SCC required by the AFGC recommendations. The experimental results show that the compressive strengths of SCC decreased slightly by substituting NA by RA. Finally, the decrease in free shrinkage is proportional to the percentage of RA incorporated into the composition of concrete. This reduction is mainly due to the improvement of the deformability of these materials.

Keywords: self-compacting concrete, coarse rubber aggregate, rheological characterization, mechanical performance, shrinkage

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Authors: Abubakar Muhammad Umar, Nur Adeela Yasid, Hassan Mohd Daud, Mohd Yunus Abd Shukor

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Glyphosate [N-(phosphonomethyl) glycine] is among the most broadly and generally recognised broad-spectrum herbicides used in agriculture due to its low cost and effectiveness in weed management. The pollution of glyphosate in the aquatic environment can be via water run-off from agricultural lands, or by spray drift, aerial spraying or due to industrial discharge, which may be seen as a threat to aquatic biota. Fish is one of the best organisms to study the toxicological aspects of glyphosate. A 49 days experiment was conducted under laboratory conditions to ascertain the effects of technical grade glyphosate on behaviour and histopathological conditions in the gills of red hybrid tilapia using a light inverted microscope. Air gasping, erratic swimming, fin movement, mucus secretion, hemorrhages, and loss of scales were observed as behavioural changes in the exposed fish. There was no histopathological complication observed in the gill of the control fish, but various levels of alterations were seen in the gills of the fish exposed to glyphosate herbicide. These include lifting of primary lamella, congestion of secondary lamella, as well as hyperplasia in both primary and secondary gill lamella, and hypertrophy of secondary gill lamella. Based on the findings of this study, glyphosate herbicide exerts behavioural and histopathological changes in the gill of red hybrid tilapia, and therefore, the fish is considered a good bioindicator in aquatic environment monitoring. Excessive usage of glyphosate herbicide near aquatic habitats should be discouraged.

Keywords: behavioural, histopathological, Oreochromis niloticus, glyphosate

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Authors: Adepoju A. A., Olapade-Ogunwole F., Ganiyu M. O.

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This study examined women's empowerment in cassava production in southwest Nigeria. The contributions of the five domains namely decision about agricultural production, decision-making power over productive resources, control of the use of income, leadership and time allocation to women disempowerment, profiled the women based on their socio-economics features and determined factors influencing women's disempowerment. Primary data were collected from the women farmers and processors through the use of structured questionnaires. Purposive sampling was used to select the LGAs and villages based on a large number of cassava farmers and processors, while cluster sampling was used to select 360 respondents in the study area. Descriptive statistics such as bar charts and percentages, Women Empowerment in Agriculture (WEAI), and the Logit regression model were used to analyze the data collected. The results revealed that 63.88% of the women were disempowered. Lack of decision-making power over productive resources; 36.47% and leadership skills; 33.26% contributed mostly to the disempowerment of the women. About 85% of the married women were disempowered, while 76.92% of the women who participated in social group activities were more empowered than their disempowered counterparts. The findings showed that women with more years of processing experience have the probability of being disempowered while those who engage in farming as a primary livelihood activity, and participate in social groups among others have the tendency to be empowered. In view of this, it was recommended that women should be encouraged to farm and contribute to social group activities.

Keywords: cassava, production, empowerment, southwest, Nigeria

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Authors: J. Vyas, R. Kazys, J. Sestoke

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Air-coupled ultrasonic is the contactless ultrasonic measurement approach which has become widespread for material characterization in Aerospace industry. It is always essential for the requirement of lightest weight, without compromising the durability. To archive the requirements, composite materials are widely used. This paper yields analysis of the air-coupled ultrasonics for composite materials such as CFRP (Carbon Fibre Reinforced Polymer) and GLARE (Glass Fiber Metal Laminate) and honeycombs for the design of modern aircrafts. Laser vibrometry could be the key source of characterization for the aerospace components. The air-coupled ultrasonics fundamentals, including principles, working modes and transducer arrangements used for this purpose is also recounted in brief. The emphasis of this paper is to approach the developed NDT techniques based on the ultrasonic guided waves applications and the possibilities of use of laser vibrometry in different materials with non-contact measurement of guided waves. 3D assessment technique which employs the single point laser head using, automatic scanning relocation of the material to assess the mechanical displacement including pros and cons of the composite materials for aerospace applications with defects and delaminations.

Keywords: air-coupled ultrasonics, contactless measurement, laser interferometry, NDT, ultrasonic guided waves

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Authors: Husain Rajib, K. S. Kishor, D. G. Jewel

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Background: Uncorrected refractive error is a common cause of preventable visual impairment in pediatric age group which can be lead to blindness but early detection of visual impairment can reduce the problem that will have good effective in education and more involve in social activities. Glasses are the cheapest and commonest form of correction of refractive errors. To achieve this, patient must exhibit good compliance to spectacle wear. Patient’s attitude and perception of glasses and eye health could affect compliance. Material and method: A Prospective community based cross sectional study was designed in order to evaluate the knowledge, attitude and practices about refractive errors and eye health amongst the primary school going children. Result: Among 140 respondents, 72 were males and 68 were females. We found 50 children were myopic and out of them 26 were male and 24 were female, 27 children were hyperopic and out of them 14 were male and 13 were female. About 63 children were astigmatic and out of them 32 were male and 31 were female. The level of knowledge, attitude was satisfactory. The attitude of the students, teachers and parents was cooperative which helps to do cycloplegic refraction. Practice was not satisfactory due to social stigma and information gap. Conclusion: Knowledge of refractive error and acceptance of glasses for the correction of uncorrected refractive error. Public awareness program such as vision screening program, eye camp, and teachers training program are more beneficial for wearing and prescribing spectacle.

Keywords: refractive error, stigma, knowledge, attitude, practice

Procedia PDF Downloads 266

Authors: Artem Kim, Clara Savary, Christele Dubourg, Wilfrid Carre, Houda Hamdi-Roze, Valerie Dupé, Sylvie Odent, Marie De Tayrac, Veronique David

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Holoprosencephaly (HPE) is a rare congenital brain malformation resulting from the incomplete separation of the two cerebral hemispheres. It is characterized by a wide phenotypic spectrum and a high degree of locus heterogeneity. Genetic defects in 16 genes have already been implicated in HPE, but account for only 30% of cases, suggesting that a large part of genetic factors remains to be discovered. HPE has been recently redefined as a complex multigenic disorder, requiring the joint effect of multiple mutational events in genes belonging to one or several developmental pathways. The onset of HPE may result from accumulation of the effects of multiple rare variants in functionally-related genes, each conferring a moderate increase in the risk of HPE onset. In order to decipher the genetic basis of HPE, unconventional patterns of inheritance involving multiple genetic factors need to be considered. The primary objective of this study was to uncover possible disease causing combinations of multiple rare variants underlying HPE by performing trio-based Whole Exome Sequencing (WES) of familial cases where no molecular diagnosis could be established. 39 families were selected with no fully-penetrant causal mutation in known HPE gene, no chromosomic aberrations/copy number variants and without any implication of environmental factors. As the main challenge was to identify disease-related variants among a large number of nonpathogenic polymorphisms detected by WES classical scheme, a novel variant prioritization approach was established. It combined WES filtering with complementary gene-level approaches: transcriptome-driven (RNA-Seq data) and clinically-driven (public clinical data) strategies. Briefly, a filtering approach was performed to select variants compatible with disease segregation, population frequency and pathogenicity prediction to identify an exhaustive list of rare deleterious variants. The exome search space was then reduced by restricting the analysis to candidate genes identified by either transcriptome-driven strategy (genes sharing highly similar expression patterns with known HPE genes during cerebral development) or clinically-driven strategy (genes associated to phenotypes of interest overlapping with HPE). Deeper analyses of candidate variants were then performed on a family-by-family basis. These included the exploration of clinical information, expression studies, variant characteristics, recurrence of mutated genes and available biological knowledge. A novel bioinformatics pipeline was designed. Applied to the 39 families, this final integrated workflow identified an average of 11 candidate variants per family. Most of candidate variants were inherited from asymptomatic parents suggesting a multigenic inheritance pattern requiring the association of multiple mutational events. The manual analysis highlighted 5 new strong HPE candidate genes showing recurrences in distinct families. Functional validations of these genes are foreseen.

Keywords: complex genetic disorder, holoprosencephaly, multiple rare variants, whole exome sequencing

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Authors: Pooja Verma, Rajnesh Tyagi, Sunil Mohan

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Al-Si alloys are widely used in various components such as liner-less engine blocks, piston, compressor bodies and pumps for automobile sector and aerospace industries due to their excellent combination of properties like low thermal expansion coefficient, low density, excellent wear resistance, high corrosion resistance, excellent cast ability, and high hardness. The low density and high hardness of primary Si phase results in significant reduction in density and improvement in wear resistance of hypereutectic Al-Si alloys. Keeping in view of the industrial importance of the alloys, hypereutectic Al-Si alloys containing 14, 16, 18 and 20 wt. % of Si were prepared in a resistance furnace using adequate amount of deoxidizer and degasser and their erosion behavior was evaluated by conducting tests at impingement angles of 30°, 60°, and 90° with an erodent discharge rate of 7.5 Hz, pressure 1 bar using erosion test rig. Microstructures of the cast alloys were examined using Optical microscopy (OM) and scanning electron microscopy (SEM) and the presence of Si particles was confirmed by x-ray diffractometer (XRD). The mechanical properties and hardness were measured using uniaxial tension tests at a strain rate of 10-3/s and Vickers hardness tester. Microstructures of the alloys and X-ray examination revealed the presence of primary and eutectic Si particles in the shape of cuboids or polyhedral and finer needles. Yield strength (YS), ultimate tensile strength (UTS), and uniform elongation of the hypereutectic Al-Si alloys were observed to increase with increasing content of Si. The optimal strength and ductility was observed for Al-20 wt. % Si alloy which is significantly higher than the Al-14 wt. % Si alloy. The increased hardness and the strength of the alloys with increasing amount of Si has been attributed presence of Si in the solid solution which creates strain, and this strain interacts with dislocations resulting in solid-solution strengthening. The interactions between distributed primary Si particles and dislocations also provide Orowan strengthening leading to increased strength. The steady state erosion rate was found to decrease with increasing angle of impact as well as Si content for all the alloys except at 900 where it was observed to increase with the increase in the Si content. The minimum erosion rate is observed in Al-20 wt. % Si alloy at 300 and 600 impingement angles because of its higher hardness in comparison to other alloys. However, at 90° impingement angle the wear rate for Al-20 wt. % Si alloy is found to be the minimum due to deformation, subsequent cracking and chipping off material.

Keywords: Al-Si alloy, erosion wear, cast alloys, dislocation, strengthening

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Authors: Joaquim de Almeida Dultra, Daiana Cristina Pereira Santana, Fátima Karoline Alves Araújo Dultra, Liliane Akemi Kawano Shibasaki, Mariana Machado Mendes de Carvalho, Ieda Margarida Crusoé Rocha Rebello

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Defects originating from mandibular resections can cause significant functional impairment and facial disharmony, and they have complex rehabilitation. The aim of this report is to demonstrate the authors' experience facing challenging rehabilitation after mandibular resection in a patient with ameloblastoma. Clinical and surgical steps are described simultaneously, highlighting the adaptation of the final fixed prosthesis, reported in an unprecedented way in the literature. A 37-year-old male patient was seen after a sports accident, where a pathological fracture in the symphysis and left mandibular body was identified, where a large radiolucent lesion was found. The patient underwent resection, bone graft, distraction osteogenesis, rehabilitation with dental implants, prosthesis, and finally, orofacial harmonization, in an interval of six years. Rehabilitation should consider the patient's needs individually and should have as the main objective to provide similar aesthetics and function to that present before the disease. We also emphasize the importance of interdisciplinary work during the course of rehabilitation.

Keywords: ameloblastoma, mandibular reconstruction, distraction osteogenesis, dental implants. dental prosthesis, implant-supported, treatment outcome

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Authors: Rudzani Lusunzi, Frans Waanders, Elvis Fosso-Kankeu, Robert Khashane Netshitungulwana

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The Sabie Goldfield has a history of gold mining dating back more than a century. Acid mine drainage (AMD) from the Nestor mine tailings storage facility (MTSF) poses a serious threat to the nearby ecosystem, specifically the Sabie River system. This study aims at developing mitigation measures for the AMD emanating from the Nestor MTSF using materials from the Glynns Lydenburg MTSF. The Nestor MTSF (NM) and the Glynns Lydenburg MTSF (GM) each provided about 20 kg of bulk composite samples. Using samples from the Nestor MTSF and the Glynns Lydenburg MTSF, two mixtures were created. MIX-A is a mixture that contains 25% weight percent (GM) and 75% weight percent (NM). MIX-B is the name given to the second mixture, which contains 50% AN and 50% AG. The same static test, i.e., acid–base accounting (ABA), net acid generation (NAG), and acid buffering characteristics curve (ABCC) was used to estimate the acid-generating probabilities of samples NM and GM for MIX-A and MIX-B. Furthermore, the mineralogy of the Nestor MTSF samples consists of the primary acid-producing mineral pyrite as well as the secondary minerals ferricopiapite and jarosite, which are common in acidic conditions. The Glynns Lydenburg MTSF samples, on the other hand, contain primary acid-neutralizing minerals calcite and dolomite. Based on the assessment conducted, materials from the Glynns Lydenburg are capable of neutralizing AMD from Nestor MTSF. Therefore, the alkaline tailings materials from the Glynns Lydenburg MTSF can be used to rehabilitate the acidic Nestor MTSF.

Keywords: Nestor Mine, acid mine drainage, mitigation, Sabie River system

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Authors: Howard Prosser

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This paper examines how critical thinking is framed, especially for primary-school students, in the recently established Australian Curriculum: History. Critical thinking is one of the curriculum’s 'general capabilities.' History provides numerous opportunities for critical thinking’s application in everyday life. The so-called 'history wars' that took place just prior to the curriculum’s introduction in 2014 sought to bring to light the limits of a singular historical narrative and reveal that which had been repressed. Consequently, the Australian history curriculum reflects this shifting mindset. Teachers are presented with opportunities to treat history in the classroom as a repository of social possibility, especially related to democratic potential, beyond hackneyed and jingoistic tales of Australian nationhood. Yet such opportunities are not explicit within the document and are up against pre-existing pedagogic practices. Drawing on political thinker Cornelius Castoriadis’s rendering of the 'social-historical' and 'paidea,' as well as his mobilisation of psychoanalysis, the study outlines how the curriculum’s critical-thinking component opens up possibilities for students and teachers to revise assumptions about how history is understood. This ontological shift is ultimately creative: the teachers’ imaginations connect the students’ imaginations, and vice versa, to the analysis that is at the heart of historical thinking. The implications of this social imagination add to the current discussions about historical consciousness among scholars like Peter Seixas. But, importantly, it has practical application in the primary-school classroom where history becomes creative acts, like play, that is indeterminate and social rather than fixed and individual.

Keywords: Australia, Castoriadis, critical thinking, history, imagination

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Authors: Mitchell Gohnert, Ryan Bradley

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This paper reviews some fundamental concepts of structural optimization, which are based on the type of materials used in construction and the shape of the structure. The first step in structural optimization is to break down all internal forces in a structure into fundamental stresses, which are tensions and compressions. Knowing the stress patterns directs our selection of structural shapes and the most appropriate type of construction material. In our selection of materials, it is essential to understand all construction materials have flaws, or micro-cracks, which reduce the capacity of the material, especially when subjected to tensions. Because of material defects, many construction materials perform significantly better when subjected to compressive forces. Structures are also more efficient if bending moments are eliminated. Bending stresses produce high peak stresses at each face of the member, and therefore, substantially more material is required to resist bending. The shape of the structure also has a profound effect on stress levels. Stress may be reduced dramatically by simply changing the shape. Catenary, triangular and linear shapes are the fundamental structural forms to achieve optimal stress flow. If the natural flow of stress matches the shape of the structures, the most optimal shape is determined.

Keywords: arches, economy of stresses, material strength, optimization, shells

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Authors: Abdelkhalek Bouchikhi, Elyes Benmokhtar, Sebastien Saletzki

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The aeronautical field is experiencing issues with RF spectrum congestion due to the constant increase in the number of flights, aircrafts and telecom systems on board. In addition, these systems are bulky in size, weight and energy consumption. The cognitive radio helps particularly solving the spectrum congestion issue by its capacity to detect idle frequency channels then, allowing an opportunistic exploitation of the RF spectrum. The present work aims to propose a new use case for aeronautical spectrum sharing and to study the performances of three different detection techniques: energy detector, matched filter and cyclostationary detector within the aeronautical use case. The spectrum in the proposed cognitive radio is allocated dynamically where each cognitive radio follows a cognitive cycle. The spectrum sensing is a crucial step. The goal of the sensing is gathering data about the surrounding environment. Cognitive radio can use different sensors: antennas, cameras, accelerometer, thermometer, etc. In IEEE 802.22 standard, for example, a primary user (PU) has always the priority to communicate. When a frequency channel witch used by the primary user is idle, the secondary user (SU) is allowed to transmit in this channel. The Distance Measuring Equipment (DME) is composed of a UHF transmitter/receiver (interrogator) in the aircraft and a UHF receiver/transmitter on the ground. While the future cognitive radio will be used jointly to alleviate the spectrum congestion issue in the aeronautical field. LDACS, for example, is a good candidate; it provides two isolated data-links: ground-to-air and air-to-ground data-links. The first contribution of the present work is a strategy allowing sharing the L-band. The adopted spectrum sharing strategy is as follow: the DME will play the role of PU which is the licensed user and the LDACS1 systems will be the SUs. The SUs could use the L-band channels opportunely as long as they do not causing harmful interference signals which affect the QoS of the DME system. Although the spectrum sensing is a key step, it helps detecting holes by determining whether the primary signal is present or not in a given frequency channel. A missing detection on primary user presence creates interference between PU and SU and will affect seriously the QoS of the legacy radio. In this study, first brief definitions, concepts and the state of the art of cognitive radio will be presented. Then, a study of three communication channel detection algorithms in a cognitive radio context is carried out. The study is made from the point of view of functions, material requirements and signal detection capability in the aeronautical field. Then, we presented a modeling of the detection problem by three different methods (energy, adapted filter, and cyclostationary) as well as an algorithmic description of these detectors is done. Then, we study and compare the performance of the algorithms. Simulations were carried out using MATLAB software. We analyzed the results based on ROCs curves for SNR between -10dB and 20dB. The three detectors have been tested with a synthetics and real world signals.

Keywords: aeronautic, communication, navigation, surveillance systems, cognitive radio, spectrum sensing, software defined radio

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Authors: Mohammed Alhammad

Abstract:

The movement towards the inclusion of students with special educational needs (SEN) in mainstream schools has become widely accepted practice in many countries. However in Saudi Arabia, this is not happening. Instead the practice for students with learning difficulties (LD) is to study in special classrooms in mainstream schools and they are not included with their peers, except at break times and morning assembly, and on school trips. There are a number of barriers that face implementing inclusion for students with LD in mainstream classrooms: one such barrier is the training of teachers. The training, either pre- or in-service, that teachers receive is seen as playing an important role in leading to the successful implementation of inclusion. The aim of this presentation is to explore how pre-service training and in-service training are acting as barriers for implementing inclusion of students with LD in mainstream primary schools in Saudi Arabia from the perspective of teachers. The qualitative research approach was used to explore this barrier. Twenty-four teachers (general education teachers, special education teachers) were interviewed using semi-structured interview and a number of documents were used as method of data collection. The result showed teachers felt that not much attention was paid to inclusion in pre-services training for general education teachers and special education teachers in Saudi Arabia. In addition, pre-service training for general education teachers does not normally including modules on special education. Regarding the in-service training, no courses at all about inclusion are provided for teachers. Furthermore, training courses in special education are few. As result, the knowledge and skills required to implemented inclusion successfully.

Keywords: inclusion, learning difficulties, Saudi Arabia, training

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Authors: Ifeanyi Charles Otuokere, Victoria Nneoma Nnochiri

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Entrepreneurship generally and specifically within the rural communities in Nigeria is a fast means of bringing development within the communities. This is made possible by utmost maximization and management of available local resources to develop rural areas through good management of these local resources. This study anchors on the rural development paradigm and the integrated rural development theories to understudy the knowledge of rural entrepreneurs on rural economic development. The research study made use of surveys and descriptive analysis. The assessable population for the study, which was randomly selected, is 100 rural entrepreneurs from ten rural communities within the Ikwuano Local Government Area of Abia State. The study made use of both primary and secondary as a source of data collection with much emphasis on a primary source, although secondary data such as journals, textbooks electronic sources were also utilised. A carefully structured questionnaire drafted to extract raw data was administered to selected entrepreneurs. The findings of the study showed that developments within rural communities can only be achieved through rural entrepreneurship. This is evidenced in increased output, job creation, and most importantly, reduction of rural to urban migration, among other things. Recommendations were also made based on these findings; the researchers recommended that infrastructural developments should be made available in the rural communities and government policies should create enabling environments along with other assistance to help these rural entrepreneurs achieve their sole aim.

Keywords: economic developments, rural communities, rural development, rural entrepreneurship

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Authors: Arpit Gite

Abstract:

Purpose: We have evaluated the role of Total Neoadjuvant Therapy in patients with Locally Advanced Rectal cancer by giving Chemoradiotherapy followed by consolidation chemotherapy (CRT-CNCT) and, after that, the strategy of wait and watch. Methods: In this prospective case series, we evaluated the results of three locally advanced Rectal cancers, two cases Stage II (cT3N0) and one case Stage III ( cT4aN2). All three patients' growth was 4-6 cm from the anal verge. We have treated with Chemoradiotherapy to dose of 45Gy/25 Fractions to elective nodal regions (Inguinal node in anal canal Involvement)and Primary and mesorectum (Phase I) followed by 14.4Gy/8 Fractions to Primary and Mesorectum(Phase II) to a total dose of 59.4Gy/33 Fractions with concurrent chemotherapy Tab Capecitabine 825mg/m2 PO BD with Radiation therapy. After 6 weeks of completion of Chemoradiotherapy, advised six cycles of consolidative chemotherapy, CAPEOX regimen, Oxaliplatin 130mg/m2 on day 1 and Capecitabine 1000mg/m2 PO BD on days 1-14 repeated on a 21-day cycle for a total of six cycles. The primary endpoint is Disease-free survival (DFS); the secondary endpoint is adverse events related to chemoradiotherapy. Radiation toxicity is assessed by RTOG criteria, and chemotherapy toxicity is assessed by Common Terminology Criteria for Adverse Events (CTCAE) Version 5.0. Results: After 6 weeks of completion of Chemoradiotherapy, we did PET-CT of all three patients; all three patients had a clinically complete response and we advised 6 cycles of consolidative chemotherapy. After completion of consolidative chemotherapy, again PET-CT and sigmoidoscopy, all three patients had complete response on PET-CT and no lesions on sigmoidoscopy and kept all three patients on wait and watch.2 patients had Grade 2 skin toxicities,1 patient had Grade 1 skin toxicity, .2 patients had Grade 2 lower GI toxicities, and 1 patient had Grade lower GI toxicity, both according to RTOG criteria. 3 patients had Grade 2 diarrhea due to capecitabine, and 1 patient had Grade 1 thrombocytopenia due to oxaliplatin assessed by Common Terminology Criteria for Adverse Events (CTCAE) Version 5.0. Conclusion: Sphincter Preservation is possible with this regimen in those who don’t want to opt for surgery or in case of low-lying rectal cancer.

Keywords: locally advanced rectal cancer, sphincter preservation, chemoradiotherapy, consolidative chemotherapy

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Authors: Bendjazia Radia, Samira Kilani-Morakchi, Nadia Aribi

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Azadirachtin is a biorational insecticide commonly reported as selective to a range of beneficial insects. It is one of the most biologically active natural inhibitors of insect growth and development and it is known to be an antagonist of the juvenile hormone and 20-hydroxyecdysone (20E). However, its mechanism of action remains still unknown. In the present study, the toxicity of a commercial formulation of Azadirachtin (Neem Azal, 1% azadirachtine) was evaluated by topical application at various doses (0.1, 0.25, 0.5, 1 and 2 µg/insect) on the third instars larvae of D. melanogaster. Lethal doses (LD25: 0.28µg and LD50: 0.67µg), were evaluated by cumulated mortality at the immature stages. The effects of azadirachtin (LD25 and LD50) were then evaluated on the development (duration of the larval and pupal instars, the weight of larvae, pupa and adults) of Drosophila melanogaster. Results showed that the insecticide increased significantly the larval and pupal instar duration. A reduction of larval and pupal weight is noted under azadirachtin treatment as compared to controls. In addition, the weight of surviving adults at the two tested dose was also reduced. In conclusion, azadirachtin seemed to interfere with the functions of the endocrine system resulting in development defects.

Keywords: azadirachtin, d.melanogaster, toxicity, development

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Authors: Lakshmi Rao Kandukuri, Mamata Deenadayal, Suma Prasad, Bipin Sethi, Srinadh Buragadda, Lalji Singh

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Worldwide; at least 7.6 million children are born annually with severe genetic or congenital malformations and among them 90% of these are born in mid and low-income countries. Precise prevalence data are difficult to collect, especially in developing countries, owing to the great diversity of conditions and also because many cases remain undiagnosed. The genetic and congenital disorder is the second most common cause of infant and childhood mortality and occurs with a prevalence of 25-60 per 1000 births. The higher prevalence of genetic diseases in a particular community may, however, be due to some social or cultural factors. Such factors include the tradition of consanguineous marriage, which results in a higher rate of autosomal recessive conditions including congenital malformations, stillbirths, or mental retardation. Genetic diseases can vary in severity, from being fatal before birth to requiring continuous management; their onset covers all life stages from infancy to old age. Those presenting at birth are particularly burdensome and may cause early death or life-long chronic morbidity. Genetic testing for several genetic diseases identifies changes in chromosomes, genes, or proteins. The results of a genetic test can confirm or rule out a suspected genetic condition or help determine a person's chance of developing or passing on a genetic disorder. Several hundred genetic tests are currently in use and more are being developed. Chromosomal abnormalities are the major cause of human suffering, which are implicated in mental retardation, congenital malformations, dysmorphic features, primary and secondary amenorrhea, reproductive wastage, infertility neoplastic diseases. Cytogenetic evaluation of patients is helpful in the counselling and management of affected individuals and families. We present here especially chromosomal abnormalities which form a major part of genetic disease burden in India. Different programmes on chromosome research and human reproductive genetics primarily relate to infertility since this is a major public health problem in our country, affecting 10-15 percent of couples. Prenatal diagnosis of chromosomal abnormalities in high-risk pregnancies helps in detecting chromosomally abnormal foetuses. Such couples are counselled regarding the continuation of pregnancy. In addition to the basic research, the team is providing chromosome diagnostic services that include conventional and advanced techniques for identifying various genetic defects. Other than routine chromosome diagnosis for infertility, also include patients with short stature, hypogonadism, undescended testis, microcephaly, delayed developmental milestones, familial, and isolated mental retardation, and cerebral palsy. Thus, chromosome diagnostics has found its applicability not only in disease prevention and management but also in guiding the clinicians in certain aspects of treatment. It would be appropriate to affirm that chromosomes are the images of life and they unequivocally mirror the states of human health. The importance of genetic counseling is increasing with the advancement in the field of genetics. The genetic counseling can help families to cope with emotional, psychological, and medical consequences of genetic diseases.

Keywords: India, chromosome abnormalities, genetic disorders, cytogenetic study

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Authors: Chengzhu Liao, Jianbo Zhang, Haiou Wang, Jing Ming, Huili Li, Yanyan Li, Hua Cheng, Sie Chin Tjong

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Since Bonfield’s group’s pioneer work, there has been growing interest amongst the materials scientists, biomedical engineers and surgeons in the use of novel biomaterials for the treatment of bone defects and injuries. This study focuses on the fabrication, mechanical characterization and biocompatibility evaluation of high density polyethylene (HDPE) reinforced with hydroxyapatite nanorods (HANR) and carbon nanofibers (CNF). HANRs of 20 wt% and CNFs of 0.5-2 wt% were incorporated into HDPE to form biocomposites using traditional melt-compounding and injection molding techniques. The mechanical measurements show that CNF additions greatly improve the tensile strength and Young’s modulus of HDPE and HDPE-20% nHA composites. Meanwhile, the nHA and CNF fillers were found to be effective to improve dimensional and thermal stability of HDPE. The results of osteoblast cell cultivation and dimethyl thiazolyl diphenyl thiazolyl tetrazolium (MTT) tests showed that the HDPE/ CNF-nHA nanocomposites are biocompatible. Such HDPE/ CNF-nHA hybrids are found to be potential biomaterials for making orthopedic joint/bone replacements.

Keywords: biocompatibility, biocomposite, carbon nanofiber, high density polyethylene, hydroxyapatite

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Authors: Onyeke Paul Chuks

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Nigeria is ranked among the developing nations and a country with a low income per capita. The consequences of this economic situation have led to the low achievement records below UN benchmark especially in the area of basic education for her citizens. The country is, however, making relentless efforts at arresting the situation by making budgetary allocations to ensure the realization of Millennium Development Goal No. 2 which is achieving universal basic education, her distressed economy notwithstanding. Basic education which comprises primary and lower secondary education as well as pre-primary and/or adult literacy programs have suffered serious setbacks orchestrated by the dwindling of the nation’s economy. This category of education being the bedrock of all other levels of education is regarded as a priority by developing countries and also the focus of the Education for All Movement led by UNESCO. The introduction of child-friendly school model is one of the strategies designed by UNESCO to achieving this all important MDGs goal No. 2. Child-friendly education model is aimed at replacing the out-dated, mundane, regimented and officious school administrative model where the basic rights of school children are trampled upon with impunity and community participation in school activities is viewed as unnecessary interference by school managers. This paper ex-rayed the potential obstacles likely to impinge on the implementation of child-friendly school model in Nigeria especially from the angle of her distressed economy and the colossal effects of the corrupt practices bedeviling the nation. The paper as well outlines prospects for the successful implementation of the child-friendly school model in Nigeria.

Keywords: child-friendly school, distressed economy, model, Nigeria

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Authors: Shivani Kuttuva, James Sampson, Timothy Simmons, Vinayak Thattaruparambil, Holly Burton, Peter Coyne

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Anogenital mammary-like glands were established to be embryological remnants of breast tissue due to failed resolution of the ectodermal mammary ridge. However, recent studies are now considering this to represent normal constituents of the anogenital area with histological resemblance to the orthotopic breast tissue with multiple benign and malignant lesions arising from it. The incidence of the above has been predominant in females in the vulval region. Due to the paucity of cases reported in men, this poses a diagnostic and therapeutic challenge resulting in a delay in treatment and, thereby, poor outcomes. Our patient presented to the dermatology clinic with an itchy, purplish lesion in the peri-anal region which, on punch biopsy, was diagnosed to be Extra-mammary Paget’s disease and taken up for Wide local excision. Immunochemically, staining was positive for HER2, ER and Cytokeratin 7, keeping with the presence of actual breast tissue with no primary breast carcinoma. Due to the invasive nature of the disease, he required Abdominoperineal resection with flap reconstruction. Despite complete surgical clearance and adjuvant radiotherapy, the disease progressed to adjacent inguinal and obturator lymph nodes with origin resembling anogenital type mammary glands but histology negative for hormonal receptors of the breast.

Keywords: anogenital mammary-like glands, abdominoperineal resection, ectopic breast tissue, ectopic male breast carcinoma, peri-anal skin lesion

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Authors: Mohammed Alateeq, Abdulaziz Alrshoud

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Objectives: To examine the attitude and practice of family physicians in giving smoking cessation advice at King Abdul-Aziz Medical City for National Guard, Riyadh. Methods: Cross sectional study using validated self-reported questionnaire that distributed to all family physicians and primary health care doctors at the four main family medicine and primary health care centers, KAMC, Riyadh. Results: 73 physicians are contributed in this study. 28 (38.4%) physicians were from (KASHM ALAN) clinic, 26 (35.6%) physicians were from (UM ALHAMAM) Clinic. 13 (17.8%) physicians were from (ISKAN) clinic. 6 (8.2%) physicians were from the Employee Health Clinic. 73 (100%) of the target population agreed that giving brief smoking cessation advice is part of their duties. 67 (91.7%) agreed that Presence of hospital guidelines and special clinics for smoking cessation will encourage them to provide advice. Only 5 (6.84%) received training courses (1-4 weeks) in smoking cessation interventions. Conclusion: Most of the target population agreed that brief smoking cessation advice is part of their duties. Also, they agreed that Presence of hospital guidelines and special clinics for smoking cessation will encourage them to provide advice although most of them did not received a formal training in smoking cessation advice.

Keywords: advice, attitude, cessation, family physicians, smoking

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