118 research outputs found

    THE EFFECT OF DISSOLVED PLASTIC POLYMER MODIFICATION ON RUTTING AND FATIGUE RESISTANCE PROPERTIES OF WARM BITUMEN BLEND

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    Recently, large amounts of waste polymers are being generated in Nigeria. One of the waste polymers is plastic bottles. Hot Mix Asphalt (HMA) are produced at high temperatures with high energy consumption and environmental hazard. The purpose of using Warm Mix Asphalt (WMA) is to reduce the production and laying temperature and emission of greenhouse gases. Therefore, this research investigated the effect of Dissolved Plastic Bottle (DPB) on the rheological, rutting and fatigue resistance properties of warm bitumen blend thereby reducing the environmental hazard associated with the Waste Plastic Bottles (WPB) disposal and consequently improving pavement service life. WPB was obtained from different waste generation points in Adeleke University, Ede, Nigeria. The obtained WPB was shredded and converted to dissolved form using pyrolysis machine @ 4500C. 500g of 60/70 penetration grade bitumen was heated in an oven with 3% (15g) sasobit until it becomes fluidal. The bitumen was modified with 0 - 17% by weight of the bitumen at 2% interval. Mixing was continued for 1hour to produce homogenous bituminous mixtures. Rheological tests were then conducted on the prepared samples using the Brookfield programmable rheometer. The results indicated that addition of DPB improves the rheological properties of absolute viscosity, phase angle, complex shear modulus, rutting and fatigue resistance of modified binder at both 135°C and 165°C. Therefore, DPB can be used to improve bitumen rheological properties and subsequently resist rutting and fatigue on traffic roads. This can best be achieved upon 7% and 5% modification levels at 135°C and 165°C respectively

    Prevalence of self-harm among lesbian, gay, bisexual, and transgender adolescents: a comparison of personal and social adversity with a heterosexual sample in Ghana

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    Objectives We sought to estimate the prevalence of self-reported self-harm among adolescents identifying as lesbian, gay, bisexual, and transgender (LGBT) in Ghana, and compare self-reported personal and social adversities related to self-harm in this group to those in a random sample of heterosexual adolescents from the same locality. Results A total of 444 adolescents aged 13-21 years, comprising 74 LGBT adolescents and 370 heterosexual adolescents, provided data. The lifetime prevalence estimate of self-harm was higher in the LGBT group (47%) than the heterosexual group (23%). The LGBT group reported a higher rate of self-harm during the previous 12 months (45%), compared to the heterosexual group (18%). LGBT adolescents reported more alcohol and substance use and more personal social adversities, including various forms of victimisation, than heterosexual adolescents. They were no more likely to report difficulty in making and keeping friends or schoolwork problems than were heterosexual adolescents

    International Association of Dental Traumatology guidelines for the management of traumatic dental injuries: 3. Injuries in the Primary Dentition

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    Traumatic injuries to the primary dentition present special problems that often require far different management when compared to that used for the permanent dentition. The International Association of Dental Traumatology (IADT) has developed these Guidelines as a consensus statement after a comprehensive review of the dental literature and working group discussions. Experienced researchers and clinicians from various specialties and the general dentistry community were included in the working group. In cases where the published data did not appear conclusive, recommendations were based on the consensus opinions or majority decisions of the working group. They were then reviewed and approved by the members of the IADT Board of Directors. The primary goal of these Guidelines is to provide clinicians with an approach for the immediate or urgent care of primary teeth injuries based on the best evidence provided by the literature and expert opinions. The IADT cannot, and does not, guarantee favorable outcomes from strict adherence to the Guidelines, However, the IADT believes their application can maximize the probability of favorable outcomes

    Novel <i>GREM1 </i>Variations in Sub-Saharan African Patients With Cleft Lip and/or Cleft Palate

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    Objective: Cleft lip and/or cleft palate (CL/P) are congenital anomalies of the face and have multifactorial etiology, with both environmental and genetic risk factors playing crucial roles. Though at least 40 loci have attained genomewide significant association with nonsyndromic CL/P, these loci largely reside in noncoding regions of the human genome, and subsequent resequencing studies of neighboring candidate genes have revealed only a limited number of etiologic coding variants. The present study was conducted to identify etiologic coding variants in GREM1, a locus that has been shown to be largely associated with cleft of both lip and soft palate. Patients and Method: We resequenced DNA from 397 sub-Saharan Africans with CL/P and 192 controls using Sanger sequencing. Following analyses of the sequence data, we observed 2 novel coding variants in GREM1. These variants were not found in the 192 African controls and have never been previously reported in any public genetic variant database that includes more than 5000 combined African and African American controls or from the CL/P literature. Results: The novel variants include p.Pro164Ser in an individual with soft palate cleft only and p.Gly61Asp in an individual with bilateral cleft lip and palate. The proband with the p.Gly61Asp GREM1 variant is a van der Woude (VWS) case who also has an etiologic variant in IRF6 gene. Conclusion: Our study demonstrated that there is low number of etiologic coding variants in GREM1, confirming earlier suggestions that variants in regulatory elements may largely account for the association between this locus and CL/P. </jats:sec

    International Association of Dental Traumatology guidelines for the management of traumatic dental injuries: 2. Avulsion of permanent teeth

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    Avulsion of permanent teeth is one of the most serious dental injuries. Prompt and correct emergency management is essential for attaining the best outcome after this injury. The International Association of Dental Traumatology (IADT) has developed these Guidelines as a consensus statement after a comprehensive review of the dental literature and working group discussions. It represents the current best evidence and practice based on that literature search and expert opinions. Experienced researchers and clinicians from various specialties and the general dentistry community were included in the working group. In cases where the published data did not appear conclusive, recommendations were based on consensus opinions or majority decisions of the working group. They were then reviewed and approved by the members of the IADT Board of Directors. The purpose of these Guidelines is to provide clinicians with the most widely accepted and scientifically plausible approaches for the immediate or urgent care of avulsed permanent teeth. The IADT does not, and cannot, guarantee favorable outcomes from adherence to the Guidelines. However, the IADT believes that their application can maximize the probability of favorable outcomes

    The aetiology of rickets-like lower limb deformities in Malawian children

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    Summary: Debilitating rickets-like lower limb deformities are common in children throughout the world, particularly in Malawi, Africa where the causes are unknown. We have identified that Blount disease and calcium deficiency rickets are the likely causes of these deformities and propose calcium supplementation as a potential treatment of Malawian rickets. Introduction: Surgical correction of rickets-like lower limb deformities is the most common paediatric operation performed at Beit Cure Orthopaedic Hospital, Malawi. The aim of this study was to investigate the aetiology of these deformities. Methods: Children with a tibio-femoral angle of deformity >20° were enrolled (n = 42, 3.0–15.0 years). Anthropometric and early life and well-being data were collected. Early morning serum and urine samples were collected on the morning of the operation for markers of calcium and phosphate homeostasis. Knee radiographs were obtained, and the children were diagnosed with either Blount (BD, n = 22) or evidence of rickets disease (RD, n = 20). As BD is a mechanical rather than metabolic disease, BD were assumed to be biochemically representative of the local population and thus used as a local reference for RD. Results: There were no differences in anthropometry or early life experiences between BD and RD. Parathyroid hormone (PTH), 1,25-dihydroxyvitamin D, total alkaline phosphatase and urinary phosphate were significantly higher and serum phosphate, 25-hydroxyvitamin D (25OHD) and tubular maximal reabsorption of phosphate significantly lower in RD than BD. There was no difference in serum calcium, fibroblast growth factor 23 or markers of iron status between groups. All children had 25OHD > 25 nmol/L. Conclusions: Vitamin D deficiency is not implicated in the aetiology of RD or BD in Malawian children. The cause of RD in Malawi is likely to be dietary calcium deficiency leading to elevated PTH resulting in increased losses of phosphate from the bone and glomerular filtrate. The causes of BD remain unclear; there was no evidence in support of previously suggested risk factors such as being overweight or starting to walk early. Prior to surgical intervention, supplementation with calcium should be considered for children with RD

    International Association of Dental Traumatology guidelines for the management of traumatic dental injuries: 1. Fractures and luxations

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    Traumatic dental injuries (TDIs) of permanent teeth occur frequently in children and young adults. Crown fractures and luxations of these teeth are the most commonly occurring of all dental injuries. Proper diagnosis, treatment planning and follow up are important for achieving a favorable outcome. Guidelines should assist dentists and patients in decision making and in providing the best care possible, both effectively and efficiently. The International Association of Dental Traumatology (IADT) has developed these Guidelines as a consensus statement after a comprehensive review of the dental literature and working group discussions. Experienced researchers and clinicians from various specialties and the general dentistry community were included in the working group. In cases where the published data did not appear conclusive, recommendations were based on the consensus opinions of the working group. They were then reviewed and approved by the members of the IADT Board of Directors. These Guidelines represent the best current evidence based on literature search and expert opinion. The primary goal of these Guidelines is to delineate an approach for the immediate or urgent care of TDIs. In this first article, the IADT Guidelines cover the management of fractures and luxations of permanent teeth. The IADT does not, and cannot, guarantee favorable outcomes from adherence to the Guidelines. However, the IADT believes that their application can maximize the probability of favorable outcomes
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