4,368 research outputs found

    K-Ar dated palynofloras in Tasmania 1: Early Oligocene, Proteacidites tuberculatus Zone sediments, Wilmot Dam, northwestern Tasmania

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    Tertiaty lake sediments at Wilmot Dam, northwestern Tasmania, are dated as Lower Proteacidites tuberculatus Zone, based on the palynological zonation developed for the Gippsland Basin in eastern Bass Strait. The age limits of Early-Middle Oligocene for this zone are in excellent agreement with a K/Ar date of 26.7 Ma for basalts capping this deposit. Three new species are described: Tricolpites stylidioides, Mutisiapollis patersonii and Periporopollenites hexaporus. The first two appear to be the earliest records to date of Stylidiaceae and Mutisia (Asteraceae:tribe Mutisieae) respectively

    The In vitro Effectiveness of Oxalate Based Desensitizing Products on Tubular Occlusion

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    Introduction: Dentine hypersensitivity (DH) is one of the most common clinically encountered conditions globally, affecting up to 74%. It has been described as a short, sharp pain resulting from changes in the fluid flow of exposed dentinal tubules, in response to physical and chemical stimuli. Objective: To compare the effectiveness of oxalate containing desensitizing products in reducing both dentine permeability and tubular occlusion vs. a control product using a recognized in vitro model. Methods: Three oxalate containing products were tested (Listerine® Advanced Defence Sensitive [LADS] mouth rinse, a 3% oxalate solution and an oxalate containing herbal toothpaste), vs. an artificial saliva control. The permeability of the acid-etched dentine discs was measured by hydraulic conductance (Lp). Dentine discs were examined using scanning electron microscopy and energy dispersive X-ray spectroscopy. After establishing the baseline permeability of the acid-etched dentine discs, discs (n=4) were randomly treated with the desensitizing products together with the addition of artificial saliva for 2 mins, followed by rinsing with distilled water (60 s). Permeability was measured at 30 s intervals for a total of 150 s. The occluded discs were acid challenged to assess tubular occlusion stability following the application of both the test and control products. Results: The oxalate containing desensitizing products in combination with artificial saliva significantly occluded the dentinal tubules by up to 65%, in comparison to the artificial saliva control that occluded ≤21% of the dentinal tubules. The occlusion associated with the oxalate containing desensitizing agents was substantially more stable in resisting an acid challenge compared to the control as determined by hydraulic conductance. Furthermore, the SEM images of the oxalate containing desensitising agents and control were consistent with the hydraulic conductance data. Of interest was that the oxalate containing herbal toothpaste deposited more precipitation on the surface than inside the tubules. The EDX analysis confirmed the presence of oxalates, calcium, and other ingredients of toothpaste. The results from the present study are in broad agreement with those of a previous study in that an oxalate containing mouth rinse provided a more stable tubular occlusion which was more resistant to an acid challenge compared to the other test products. Conclusion: Oxalate containing desensitizing agents were significantly more effective in occluding the dentinal tubules vs. an artificial saliva control. These results are of clinical significance as they demonstrate that oxalate containing desensitizing agents provide both significant and stable tubular occlusion of the open dentinal tubules following an acidic challenge

    Why alternative teenagers self-harm: exploring the link between non-suicidal self-injury, attempted suicide and adolescent identity

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    Background: The term ‘self-harm’ encompasses both attempted suicide and non-suicidal self-injury (NSSI). Specific adolescent subpopulations such as ethnic or sexual minorities, and more controversially, those who identify as ‘Alternative’ (Goth, Emo) have been proposed as being more likely to self-harm, while other groups such as ‘Jocks’ are linked with protective coping behaviours (for example exercise). NSSI has autonomic (it reduces negative emotions) and social (it communicates distress or facilitates group ‘bonding’) functions. This study explores the links between such aspects of self-harm, primarily NSSI, and youth subculture.<p></p> Methods: An anonymous survey was carried out of 452 15 year old German school students. Measures included: identification with different youth cultures, i.e. Alternative (Goth, Emo, Punk), Nerd (academic) or Jock (athletic); social background, e.g. socioeconomic status; and experience of victimisation. Self-harm (suicide and NSSI) was assessed using Self-harm Behavior Questionnaire and the Functional Assessment of Self-Mutilation (FASM).<p></p> Results: An “Alternative” identity was directly (r ≈ 0.3) and a “Jock” identity inversely (r ≈ -0.1) correlated with self-harm. “Alternative” teenagers self-injured more frequently (NSSI 45.5% vs. 18.8%), repeatedly self-injured, and were 4–8 times more likely to attempt suicide (even after adjusting for social background) than their non-Alternative peers. They were also more likely to self-injure for autonomic, communicative and social reasons than other adolescents.<p></p> Conclusions: About half of ‘Alternative’ adolescents’ self-injure, primarily to regulate emotions and communicate distress. However, a minority self-injure to reinforce their group identity, i.e. ‘To feel more a part of a group’

    Two fossil species of Metrosideros (Myrtaceae) from the Oligo-Miocene Golden Fleece locality in Tasmania, Australia

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    Premise of the Study: The capsular-fruited genus Metrosideros (Myrtaceae) is one of the most widely distributed flowering plant genera in the Pacific but is extinct in Australia today. The center of geographic origin for the genus and the reason for and timing of its extinction in Australia remain uncertain. We identify fossil Metrosideros fruits from the newly discovered Golden Fleece fossil flora in the Oligo-Miocene of Tasmania, Australia, shedding further light on these problems.Methods: Standard paleopalynological techniques were used to date the fossil-bearing sediments. Scanning electron microscopy and an auto-montage camera system were used to take high-resolution images of fossil and extant fruits taken from herbarium specimens. Fossils are identified using a nearestliving-relative approach.Key Results: The fossil-bearing sediments are palynostratigraphically dated as being Proteacidites tuberculatus Zone Equivalent (ca. 33-16 Ma) in age and provide a confident Oligo Miocene age for the macrofossils. Two new fossil species of Metrosideros are described and are here named Metrosideros dawsonii sp. nov. and Metrosideros wrightii sp. nov.Conclusions: These newly described fossil species of Metrosideros provide a second record of the genus in the Cenozoic of Australia, placing them in the late Early Oligocene to late Early Miocene. It is now apparent not only that Metrosideros was present in Australia, where the genus is now extinct, but that at least several Metrosideros species were present during the Cenozoic. These fossils further strengthen the case for an Australian origin of the genus

    CR1 Knops blood group alleles are not associated with severe malaria in the Gambia

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    The Knops blood group antigen erythrocyte polymorphisms have been associated with reduced falciparum malaria-based in vitro rosette formation (putative malaria virulence factor). Having previously identified single-nucleotide polymorphisms (SNPs) in the human complement receptor 1 (CR1/CD35) gene underlying the Knops antithetical antigens Sl1/Sl2 and McC(a)/McC(b), we have now performed genotype comparisons to test associations between these two molecular variants and severe malaria in West African children living in the Gambia. While SNPs associated with Sl:2 and McC(b+) were equally distributed among malaria-infected children with severe malaria and control children not infected with malaria parasites, high allele frequencies for Sl 2 (0.800, 1,365/1,706) and McC(b) (0.385, 658/1706) were observed. Further, when compared to the Sl 1/McC(a) allele observed in all populations, the African Sl 2/McC(b) allele appears to have evolved as a result of positive selection (modified Nei-Gojobori test Ka-Ks/s.e.=1.77, P-value <0.05). Given the role of CR1 in host defense, our findings suggest that Sl 2 and McC(b) have arisen to confer a selective advantage against infectious disease that, in view of these case-control study data, was not solely Plasmodium falciparum malaria. Factors underlying the lack of association between Sl 2 and McC(b) with severe malaria may involve variation in CR1 expression levels

    Pneumococcal carriage in sub-Saharan Africa--a systematic review.

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    BACKGROUND: Pneumococcal epidemiology varies geographically and few data are available from the African continent. We assess pneumococcal carriage from studies conducted in sub-Saharan Africa (sSA) before and after the pneumococcal conjugate vaccine (PCV) era. METHODS: A search for pneumococcal carriage studies published before 2012 was conducted to describe carriage in sSA. The review also describes pneumococcal serotypes and assesses the impact of vaccination on carriage in this region. RESULTS: Fifty-seven studies were included in this review with the majority (40.3%) from South Africa. There was considerable variability in the prevalence of carriage between studies (I-squared statistic = 99%). Carriage was higher in children and decreased with increasing age, 63.2% (95% CI: 55.6-70.8) in children less than 5 years, 42.6% (95% CI: 29.9-55.4) in children 5-15 years and 28.0% (95% CI: 19.0-37.0) in adults older than 15 years. There was no difference in the prevalence of carriage between males and females in 9/11 studies. Serotypes 19F, 6B, 6A, 14 and 23F were the five most common isolates. A meta-analysis of four randomized trials of PCV vaccination in children aged 9-24 months showed that carriage of vaccine type (VT) serotypes decreased with PCV vaccination; however, overall carriage remained the same because of a concomitant increase in non-vaccine type (NVT) serotypes. CONCLUSION: Pneumococcal carriage is generally high in the African continent, particularly in young children. The five most common serotypes in sSA are among the top seven serotypes that cause invasive pneumococcal disease in children globally. These serotypes are covered by the two PCVs recommended for routine childhood immunization by the WHO. The distribution of serotypes found in the nasopharynx is altered by PCV vaccination

    First evidence for Wollemi Pine-type pollen (Dilwynites: Araucariaceae) in South America

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    We report the first fossil pollen from South America of the lineage that includes the recently discovered, extremely rare Australian Wollemi Pine, Wollemia nobilis (Araucariaceae). The grains are from the late Paleocene to early middle Eocene Ligorio Márquez Formation of Santa Cruz, Patagonia, Argentina, and are assigned to Dilwynites, the fossil pollen type that closely resembles the pollen of modern Wollemia and some species of its Australasian sister genus, Agathis. Dilwynites was formerly known only from Australia, New Zealand, and East Antarctica. The Patagonian Dilwynites occurs with several taxa of Podocarpaceae and a diverse range of cryptogams and angiosperms, but not Nothofagus. The fossils greatly extend the known geographic range of Dilwynites and provide important new evidence for the Antarctic region as an early Paleogene portal for biotic interchange between Australasia and South America.Mike Macphail, Raymond J. Carpenter, Ari Iglesias, Peter Wil

    Toxoplasma, Toxocara and Tuberculosis co-infection in a four year old child

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    <p>Abstract</p> <p>Background</p> <p>Tuberculosis. toxocariasis and toxoplasmosis are among the common infectious causes of lymphadenitis in children. Cases of <it>Toxoplasma gondii </it>and <it>Toxocara spp </it>co-infection have been reported.</p> <p>Case Presentation</p> <p>This case report describes a co-infection of <it>Toxoplasma gondii</it>, <it>Toxocara </it>spp and tuberculosis in a child with chronic lymphadenopathy and eosinophilia.</p> <p>Conclusion</p> <p>The case report highlights two important points. First is the diagnostic challenges that are encountered by clinicians in tropical countries such as Sri Lanka, where lymphadenopathy and eosinophilia with a positive serology commonly point towards a parasitic infection. Secondly the importance of proper history taking and performing the Mantoux test as a first line investigation in a country where the incidence of tuberculosis is low, even in the absence of a positive contact history.</p

    Recognition memory, self-other source memory, and theory-of-mind in children with autism spectrum disorder.

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    This study investigated semantic and episodic memory in autism spectrum disorder (ASD), using a task which assessed recognition and self-other source memory. Children with ASD showed undiminished recognition memory but significantly diminished source memory, relative to age- and verbal ability-matched comparison children. Both children with and without ASD showed an “enactment effect”, demonstrating significantly better recognition and source memory for self-performed actions than other-person-performed actions. Within the comparison group, theory-of-mind (ToM) task performance was significantly correlated with source memory, specifically for other-person-performed actions (after statistically controlling for verbal ability). Within the ASD group, ToM task performance was not significantly correlated with source memory (after controlling for verbal ability). Possible explanations for these relations between source memory and ToM are considered
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