156 research outputs found

    Fabrication and Evaluation of a Noncompliant Molar Distalizing Appliance: Bonded Molar Distalizer

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    Objective: Attempts to treat class II malocclusions without extraction in non-compliant patients have led to utilization of intraoral molar distalizing appliances. The purpose of this study was to investigate dental and skeletal effects of Bonded Molar Distalizer (BMD) which is a simple molar distalizing appliance.Materials and Methods: Sixteen patients (12 girls, four boys) with bilateral half-cusp class II molar relationship, erupted permanent second molars and normal or vertical growth pattern were selected for bilateral distalization of maxillary molars via BMD. Thescrews were activated every other day, alternately. Lateral cephalograms and study models were obtained before treatment and after 11 weeks activation of the appliance.Results: Significant amounts of molar distalization, molar distal tipping and anchorage loss were observed. The mean maxillary first molar distal movement was 1.22±0.936 mm with a distal tipping of 2.97±3.74 degrees in 11 weeks. The rate of distal movement was0.48 mm per month. Reciprocal mesial movement of the first premolars was 2.26±1.12 mm with a mesial tipping of 4.25±3.12 degrees. Maxillary incisors moved 3.55±1.46 mm and tipped 9.87±5.03 degrees mesially. Lower anterior face height (LAFH) decreased 1.28±1.36 mm.Conclusion: BMD is appropriate for distalizing maxillary molars, especially in patients with critical LAFH, although significant amounts of anchorage loss occur using this appliance

    Out-of-plane strengthening of masonry infills using textile reinforced mortar (TRM) technique

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    Published online: 29 May 2021The out-of-plane collapse of masonry infills during seismic actions resulted in human life losses and huge repair or reconstruction costs. These problems will result in disturbance of the operational functions of the buildings. The main scope of this research is to analyze the efficiency of different strengthening techniques based on textile reinforced mortar (TRM) technique and using steel connectors in the out-of-plane direction. To accomplish the objectives, four half-scale specimens were tested under uniform out-of-plane loads applied by an airbag to each mass of the infill cyclically. The performance of the textile reinforced mortar technique by using two different meshes was also evaluated experimentally. Besides the protection of the infill from collapsing and protection of human lives, using TRM technique enhances the out-of-plane response of the specimen but its connection to the infill has to be deeply investigated.Fundação para a Ciência e Tecnologia (FCT

    Seismic performance of Portuguese masonry infill walls: From traditional systems to new solutions

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    The use of masonry infill walls in reinforced concrete structures are a common solution in Portugal and other European countries for more than 50 years. These walls are used as exterior enclosures to build the envelope of the buildings, or as interior partitions to divide the different spaces of the houses. In the building construction practice these walls are built only after the hardening of the reinforced concrete elements. For that reason, they are assumed as non-structural elements, and not considered in the structural design of the building. However, when buildings are subjected to seismic action, these walls assume a structural behavior. This leads in many cases to the existence of an unsatisfactory behavior of infill walls, resulting in damage of the walls, which put human lives in dangerous and cause extensive economic losses. This seismic vulnerability of masonry infill walls is well recognized by the scientific community and has been observed in many works carried out in the last decades, as well as the recent earthquakes in southern Europe. In the case of a seismic event of high intensity in Portugal, it is expected that similar problems will occur in the Portuguese masonry infill walls, given the similarity of the construction typologies, in southern Europe. It is therefore important to study the masonry infill walls used in Portugal over the years, to fully understand their seismic behavior, and thus be able to propose and study reinforcement systems for existing walls and new masonry infill systems for new construction. Thus, in this paper is made a characterization of masonry infill walls typologies used in Portugal over the years. A review of the mechanical behavior of masonry infill walls is carried out using several In-Plane and Out-of-Plane tests performed at the University of Minho and other studies carried out in Portugal. Several strengthening techniques possible to be used in this type of walls are presented, as well as some mechanical characterization tests of these strengthening solutions applied on Portuguese infills walls. Finally, are presented two proposals for new systems of masonry infill walls to be used in new construction, with the objective of present a better seismic behavior in this type of elementsEuropean Union’s Seventh Framework Program for research, technological development and demonstration under grant agreement No 606229, which support this work. This work was also supported by FCT (Portuguese Foundation for Science and Technology, within ISISE, project UID/ECI/04029/2013, and through a doctoral scholarship reference SFRH/BD/125094/201

    Paredes de alvenaria de enchimento e a ação sísmica: reabilitação e inovação

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    Neste trabalho apresentam-se os principais resultados da investigação efetuada na Universidade do Minho relacionada com a análise do comportamento de paredes de enchimento sujeita a ações sísmicas e metodologias de reforço com a proposta de um novo material desenvolvido na perspetiva de reabilitação destas paredes construídas em regiões sísmicas. Apresentam-se também algumas possibilidades para construção nova de paredes de enchimento que visam um desempenho melhorado quando sujeitas a ações sísmicas

    Molecular and Seroepidemiological Survey of Visceral Leishmaniasis among Humans and Domestic Dogs in Mazandaran Province, North of Iran

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    Background: New cases of visceral leishmaniasis (VL) have been reported recently in some parts of Mazandaran Province, north of Iran where the first human case of VL was reported in 1949. This study aimed to determine the present status of Leishmania infantum infection among humans and domestic dogs using serological and molecular methods in central parts of Mazandaran Province. Methods: In this cross-sectional study, blood samples were randomly collected from 402 humans and fortynine domestic dogs throughout 2009 and 2010 in the central part of Mazandaran Province including Semeskadeh and Kiakola districts where recent cases of human visceral leishmaniasis had been reported there. All the collected samples were tested by direct agglutination test (DAT) for the detection of anti-Leishmania infantum antibodies as well as convenience PCR assay on whole blood samples for detection of leishmanial infection and identification of Leishmania species. Results: None of 402 collected human (402) and dog (49) blood samples showed anti Leishmania infantum antibodies at titers 1:3200 and 1:320 as cut-off values of DAT, respectively but only 2 of domestic dogs (4.1 %) were found PCR-positive corresponding to L.infantum. Conclusion: This study confirms the circulation of L. infantum at least among domestic dogs an

    Emergence of a new focus of visceral leishmaniasis due to Leishmania infantum in Golestan Province, north-eastern of Iran

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    Over the last decade, a few cases of visceral leishmaniasis (VL) have been reported in some districts of the province of Golestan, in north-eastern Iran. The aim of the present study was to investigate the prevalence of Leishmania infantum infection among humans and domestic dogs by using direct agglutination test (DAT) and PCR assays in the eastern zone of the province. Between 2011 and 2012, blood samples were randomly collected from 450 humans and 50 domestic dogs, in the eastern zone of Golestan Province including 7 villages from Marave-tappeh district where new cases of human VL had been recorded there. Each of these samples was tested for anti-Leishmania antibodies, in DAT, and for L. infantum kinetoplast DNA on whole blood, in PCR-based assays. A total of 450 human samples, 6 (1.33 %) were found seropositive and 13 (2.8 %) was found PCR-positive. Of the 50 dog samples, 16 (32 %) were found seropositive and 15 (30 %) were PCR-positive. All PCR-positive dogs were found seropositive except one as well as 6 (46.2 %) PCR-positive humans were also found seropositive. Moreover, the species of L. infantum was detected in all PCR-positive samples. The high prevalence of VL in the study areas offer it has emerged as an endemic focus in the province. Further investigations on the vectors, reservoirs and human population are recommended. © 2013 Indian Society for Parasitology

    Assessment of Bond Strength between Metal Brackets and Non-Glazed Ceramic in Different Surface Treatment Methods

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    Objective: The aim of this study was to evaluate the bond strength between metal brackets and non-glazed ceramic with three different surface treatment methods.Materials and Methods: Forty-two non-glazed ceramic disks were assigned into three groups. Group I and II specimens were etched with 9.5% hydrofluoric acid. Subsequently in group I, silane and adhesive were applied and in group II, bonding agent was used only.In group III, specimens were treated with 35% phosphoric acid and then silane and adhesive were applied. Brackets were bonded with light-cured composites. The specimens were stored in water in room temperature for 24 hours and then thermocycled 500 times between 5°C and 55°C.Results: The difference of tensile bond strength between groups I and III was not significant(P=0.999). However, the tensile bond strength of group II was significantly lower than groups I, and III (P<0.001). The adhesive remnant index scores between the threegroups had statistically significant differences (P<0.001).Conclusion: With the application of scotch bond multi-purpose plus adhesive, we can use phosphoric acid instead of hydrofluoric acid for bonding brackets to non-glazed ceramic restorations

    Epidemiological Aspects of Visceral Leishmaniasis in Baft District, Kerman Province, Southeast of Iran

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    Background: Visceral leishmaniasis (kala-azar) is an endemic disease in some areas of Iran. A cross- sectional study was conducted for sero-epidemiological survey of visceral leishmaniasis (VL) in Baft district from Kerman Province, southeast of Iran.Methods: Blood samples were collected from children up to 12 years old and 10% of adult population from Baft villages with a multi-stage randomized cluster sampling. In addition, blood samples were collected from 30 domestic dogs from the same areas. All the collected blood sam­ples were tested by direct agglutination test (DAT) for the detection of anti-Leishmania antibod­ies in both human and dog using the cut-off value of ≥1:3200 and ≥ 1:320, respectively. Parasitologi­cal, molecular, and pathological were performed on infected dogs. Chi-square and Fisher exact tests were used to compare sero-prevalence values.Results: From 1476 collected human serum samples, 23 (1.55%) showed anti-Leishmania antibod­ies at titers of 1:800 and 1:1600 whereas 14 (0.95%) showed anti-Leishmania infantum antibodies at titers of ≤ 1:3200. No statistically significant difference was found between male (1.18 %) and female (0.69%) sero-prevalence (P=0.330). Children of 5-8 years showed the high­est sero-prevalence rate (3.22%). Seven out of 30 domestic dogs (23%) showed anti-Leishmania antibodies at titers ≤1:320. Leishmania infantum was identified in five infected dogs by nested - PCR assay.Conclusion: It seems that visceral leishmaniasis is being endemic in southern villages of Baft district, southeast of Iran

    Prevalence of blood-borne viruses among Iranian dentists: Results of a national survey

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    Objectives: Health care workers, including dentists, are at the front line for acquiring blood-borne virus infections. This study aimed to investigate the prevalence of hepatitis B, hepatitis C and human immunodeficiency viruses among Iranian dentists. Material and Methods: The survey included 1628 dental health care workers who attended the 51st annual Congress of the Iranian Dental Association. Data on the risk of blood-borne virus transmission during health care and infection control practices were gathered from self-administered questionnaires. Sera were screened serologically by enzyme-linked immunosorbent assay (ELISA). The positive samples were examined by polymerase chain reaction (PRC) followed by direct sequencing. Results: Six (0.36) and 81 (5.0) were positive for hepatitis B surface antigen (HBsAg) and (anti-hepatitis B virus core antigen (anti-HBc), respectively. Only 1 (0.061) was positive for anti-hepatitis C virus (anti-HCV). No case was positive for anti-human immunodeficiency virus (anti-HIV). One case was diagnosed as being occult hepatitis B virus (HBV) infection. One thousand five hundred thirty-five (94.3) of participants had received at least 1 dose of HBV vaccine. One thousand three hundred fifty-nine (88.5) contained hepatitis B surface antibody (anti-HBs) > 10 IU/ml, of whom 55 (4.0) were anti-HBc positive, suggesting that they had been infected with HBV in the past. Anti-HBc positive cases had past histories of hepatitis, either their own or their spouses'. Individuals with inadequate anti-HBs levels (< 10 IU/ml) were significantly more prevalent among anti-HBc positive cases (p < 0.001). Conclusions: The prevalence of blood-borne viruses among dental HCWs found in this study was lower than past reports from Iranian dentists and general population. The implementation of HBV vaccination together with improvement in infection control procedures has reduced the potential for risk infection among Iranian dentists

    Disseminated Leishmaniasis Caused by Leishmania tropica in a Puppy from Karaj, Central Iran

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    A 5-month old puppy with muco-cutaneous lesions in the chin, around lips and eyes was examined physically and microscopically for leishmaniasis. Muco-cutaneous lesions containing a large number of amastigotes of Leishmania spp. were observed. Amastigotes were also detected in liver and spleen of the puppy. The animal was positive with Dipstick rK39 kit and high level of anti-Leishmania antibodies was detected by direct agglutination test (DAT). DNA, Using PCR-RFLP technique extracted from cultured Leishmania promastigotes and L. tropica was identified. This is the first report of concurrent mucosal and visceral involvement of L. tropica in a puppy from Iran
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