1,627 research outputs found

    The Effects of Laser Radiation on Exposed Dentine Surfaces in the Treatment of Dentine Sensitivity. An In Vitro Study.

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    Aim: This in vitro pilot study was undertaken to investigate the effects of Neodymium: Yttrium Aluminium Garnet (Nd:YAG), Erbium: Yttrium Aluminium Garnet (Er:YAG) and Helium Neon (HeNe) laser radiation on dentine surfaces in extracted human teeth. Material and Methods: Instrumented root surfaces and etched and unetched dentine discs were irradiated with a Nd:YAG laser operating at 3.5, 3.75 or 4W or an Er:YAG laser operating at 60, 80, 100mJ or with a HeNe laser. Results: The Nd:YAG laser produced melting and resolidification of dentine on all surfaces while the Er:YAG laser produced craters with closed tubules in root surfaces, but open tubules in dentine discs. The HeNe laser produced no apparent surface alteration. Both lased and unlased control surfaces were compared using Scanning Electron Microscopy (SEM). Conclusions: Irradiation with the Nd:YAG and Er:YAG lasers caused significant disruption of the dentine surfaces on both root surfaces and also on dentine discs. Nd:YAG radiation produced irregular melting and resolidification of the dentine surface with some occlusion of open dentine tubules. Er:YAG radiation caused ablation of dentine and produced craters with open tubules in the dentine discs, but closed tubules on most root surfaces. Irradiation using a HeNe laser produced no noticeable surface effect

    Connecting the dots between climate change, household water insecurity, and migration

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    Climate change is now considered a primary global driver of migration, with water insecurity theorized to be a key determinant. Most studies have focused on large-scale climate migration events triggered by extreme weather events such as droughts, storms, or floods. But there are few studies of how climate change shapes the everyday household-level experience of water insecurity and subsequent migration decision-making, beyond the contexts of disasters and agricultural livelihoods—an invisible ‘slow drip’ of migration. This review proposes a complementary, alternative framework for linking climate change, household-level water insecurity, and environmental migration by positioning household water insecurity as a critical pathway for shaping migration decision-making in the context of socio-environmental change. We present evidence that household water insecurity is a push factor that motivates household members to migrate due to water-related disruptions to physical and mental health, livelihoods beyond agriculture, and social relationships. We close with implications for anti-poverty and development initiatives, and for water interventions to mitigate forced climate migration

    The Far-Infrared Properties of Spatially Resolved AKARI Observations

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    We present the spatially resolved observations of IRAS sources from the Japanese infrared astronomy satellite AKARI All-Sky Survey during the performance verification (PV) phase of the mission. We extracted reliable point sources matched with IRAS point source catalogue. By comparing IRAS and AKARI fluxes, we found that the flux measurements of some IRAS sources could have been over or underestimated and affected by the local background rather than the global background. We also found possible candidates for new AKARI sources and confirmed that AKARI observations resolved IRAS sources into multiple sources. All-Sky Survey observations are expected to verify the accuracies of IRAS flux measurements and to find new extragalactic point sources.Comment: 11 pages, 7 figures, accepted publication in PASJ AKARI special issu

    Seasonal change in the daily timing of behaviour of the common vole, Microtus arvalis

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    1. Seasonal effects on daily activity patterns in the common vole were established by periodic trapping in the field and continuous year round recording of running wheel and freeding activity in cages exposed to natural meteorological conditions. 2. Trapping revealed decreased nocturnality in winter as compared to summer. This was paralelled by a winter reduction in both nocturnal wheel running and feeding time in cages. 3. Frequent trap checks revealed a 2 h rhythm in daytime catches in winter, not in summer. Cage feeding activity in daytime was always organized in c. 2 h intervals, but day-to-day variations in phase blurred the rhythm in summer in a summation of individual daily records. Thus both seasonal and short-term temporal patterns are consistent between field trappings and cage feeding records. 4. Variables associated with the seasonal change in daily pattern were: reproductive state (sexually active voles more nocturnal), age (juveniles more nocturnal), temperature (cold days: less nocturnal), food (indicated by feeding experiments), habitat structure (more nocturnal in habitat with underground tunnels). 5. Minor discrepancies between field trappings and cage feeding activity can be explained by assuming increased trappability of voles in winter. Cage wheel running is not predictive of field trapping patterns and is thought to reflect behavioral motivations not associated with feeding but with other activities (e.g., exploratory, escape, interactive behaviour) undetected by current methods, including radiotelemetry and passage-counting. 6. Winter decrease in nocturnality appears to involve a reduction in nocturnal non-feeding and feeding behaviour and is interpreted primarily as an adaptation to reduce energy expenditure in adverse but socially stable winter conditions.

    Persistence of anticancer activity in berry extracts after simulated gastrointestinal digestion and colonic fermentation

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    Fruit and vegetable consumption is associated at the population level with a protective effect against colorectal cancer. Phenolic compounds, especially abundant in berries, are of interest due to their putative anticancer activity. After consumption, however, phenolic compounds are subject to digestive conditions within the gastrointestinal tract that alter their structures and potentially their function. However, the majority of phenolic compounds are not efficiently absorbed in the small intestine and a substantial portion pass into the colon. We characterized berry extracts (raspberries, strawberries, blackcurrants) produced by in vitro-simulated upper intestinal tract digestion and subsequent fecal fermentation. These extracts and selected individual colonic metabolites were then evaluated for their putative anticancer activities using in vitro models of colorectal cancer, representing the key stages of initiation, promotion and invasion. Over a physiologically-relevant dose range (0–50 µg/ml gallic acid equivalents), the digested and fermented extracts demonstrated significant anti-genotoxic, anti-mutagenic and anti-invasive activity on colonocytes. This work indicates that phenolic compounds from berries undergo considerable structural modifications during their passage through the gastrointestinal tract but their breakdown products and metabolites retain biological activity and can modulate cellular processes associated with colon cancer

    A Good Samaritan inspired foundation for a fair health care system

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    Distributive justice on the income and on the service aspects is the most vexing modern day problem for the creation and maintenance of an all inclusive health care system. A pervasive problem of all current schemes is the lack of effective cost control, which continues to result in increasing burdens for all public and private stakeholders. This proposal posits that the responsibility and financial obligation to achieve an ideal outcome of equal and affordable access and benefits for all citizens is misplaced. The Good Samaritan demonstrated basic ethical principles, which are revisited, elaborated and integrated into a new approach to health care. The participants are limited to individual contributors and beneficiaries and organized as a citizen carried, closed, independent, and self-sufficient self-governing cooperative for their own and the benefit of a minority of disadvantaged health care consumers. The government assumes oversight, provides arbitration, enforces democratic decision making, a scheme of progressive taxation, a separate and transparent accounting system, and a balance between income and reinvestment in health care. The results are a fair distribution of cost, its effective control, and increased individual motivation to take on responsibility for personal health as a private good and a sharpened focus towards community health. At the sociopolitical level the government as well as employers are released from the inappropriate burden of catering to individual health

    Outcome of ATP-based tumor chemosensitivity assay directed chemotherapy in heavily pre-treated recurrent ovarian carcinoma

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    BACKGROUND: We wished to evaluate the clinical response following ATP-Tumor Chemosensitivity Assay (ATP-TCA) directed salvage chemotherapy in a series of UK patients with advanced ovarian cancer. The results are compared with that of a similar assay used in a different country in terms of evaluability and clinical endpoints. METHODS: From November 1998 to November 2001, 46 patients with pre-treated, advanced ovarian cancer were given a total of 56 courses of chemotherapy based on in-vitro ATP-TCA responses obtained from fresh tumor samples or ascites. Forty-four patients were evaluable for results. Of these, 18 patients had clinically platinum resistant disease (relapse < 6 months after first course of chemotherapy). There was evidence of cisplatin resistance in 31 patients from their first ATP-TCA. Response to treatment was assessed by radiology, clinical assessment and tumor marker level (CA 125). RESULTS: The overall response rate was 59% (33/56) per course of chemotherapy, including 12 complete responses, 21 partial responses, 6 with stable disease, and 15 with progressive disease. Two patients were not evaluable for response having received just one cycle of chemotherapy: if these were excluded the response rate is 61%. Fifteen patients are still alive. Median progression free survival (PFS) was 6.6 months per course of chemotherapy; median overall survival (OAS) for each patient following the start of TCA-directed therapy was 10.4 months (95% confidence interval 7.9-12.8 months). CONCLUSION: The results show similar response rates to previous studies using ATP-TCA directed therapy in recurrent ovarian cancer. The assay shows high evaluability and this study adds weight to the reproducibility of results from different centre

    Motor coordination deficits in Alpk1 mutant mice with the inserted piggyBac transposon

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    <p>Abstract</p> <p>Background</p> <p>ALPK1 (α-kinase 1) is a member of an unconventional alpha-kinase family, and its biological function remains largely unknown. Here we report the phenotypic characterization of one mutant line, in which the <it>piggyBac </it>(<it>PB</it>) transposon is inserted into the <it>Alpk1 </it>gene.</p> <p>Results</p> <p>The <it>piggyBac</it>(<it>PB</it>) insertion site in mutants was mapped to the first intron of the <it>Alpk1 </it>gene, resulting in the effective disruption of the intact <it>Alpk1 </it>transcript expression. The transposon-inserted <it>Alpk1 </it>homozygous mutants (<it>Alpk1<sup>PB/PB</sup></it>) displayed severe defects in motor coordination in a series of behavioral analysis, including dowel test, hanging wire test, rotarod analysis and footprint analysis. However, the cerebellar architecture, Purkinje cell morphology and electrophysiology of the Purkinje cells appeared normal in mutants. The motor coordination deficits in the <it>Alpk1<sup>PB/PB </sup></it>mice were rescued by transgenic mice expressing the full-length <it>Alpk1</it>-coding sequence under the control of the ubiquitous expression promoter.</p> <p>Conclusions</p> <p>Our results indicate that ALPK1 plays an important role in the regulation of motor coordination. <it>Alpk1<sup>PB/PB </sup></it>mice would be a useful model to provide a clue to the better understanding of the cellular and molecular mechanisms of ALPK1 in the control of fine motor activities.</p

    Fluoromycobacteriophages for rapid, specific, and sensitive antibiotic susceptibility testing of Mycobacterium tuberculosis

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    Rapid antibiotic susceptibility testing of Mycobacterium tuberculosis is of paramount importance as multiple- and extensively- drug resistant strains of M. tuberculosis emerge and spread. We describe here a virus-based assay in which fluoromycobacteriophages are used to deliver a GFP or ZsYellow fluorescent marker gene to M. tuberculosis, which can then be monitored by fluorescent detection approaches including fluorescent microscopy and flow cytometry. Pre-clinical evaluations show that addition of either Rifampicin or Streptomycin at the time of phage addition obliterates fluorescence in susceptible cells but not in isogenic resistant bacteria enabling drug sensitivity determination in less than 24 hours. Detection requires no substrate addition, fewer than 100 cells can be identified, and resistant bacteria can be detected within mixed populations. Fluorescence withstands fixation by paraformaldehyde providing enhanced biosafety for testing MDR-TB and XDR-TB infections. © 2009 Piuri et al
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