1,719 research outputs found

    Treating a maxillary midline diastema in adult patients: A general dentist's perspective

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    Background: A maxillary midline diastema (MMD) often is a primary concern of patients during a dental consultation. Although an MMD can be transient owing to the developing dentition and, thus, requires no active treatment, management of MMDs in the permanent dentition requires a detailed examination and appropriate care. Case Descriptions: The authors present five cases of MMDs in adults to illustrate a range of restorative and orthodontic options. In the first case, the clinician used resin-based composite buildup to close an MMD resulting from small teeth and generalized spacing in the dental arch. In the second case, the clinician placed porcelain veneers to treat an MMD in a patient with discolored dentition. In the third case, the clinician fitted a removable appliance to close an MMD by tipping the incisors palatally. In the fourth case, the clinician fitted a sectional fixed appliance to promote mesial bodily movement of the incisors. In the fifth case, the clinician placed a full-arch fixed appliance to treat an MMD caused by tilted incisors. Conclusions and Clinical Implications: Effective treatment requires an accurate diagnosis and appropriate intervention. General dentists can perform a range of restorative and orthodontic treatments in appropriate clinical situations to address patients' concerns.link_to_subscribed_fulltex

    Analysis and Computational Dissection of Molecular Signature Multiplicity

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    Molecular signatures are computational or mathematical models created to diagnose disease and other phenotypes and to predict clinical outcomes and response to treatment. It is widely recognized that molecular signatures constitute one of the most important translational and basic science developments enabled by recent high-throughput molecular assays. A perplexing phenomenon that characterizes high-throughput data analysis is the ubiquitous multiplicity of molecular signatures. Multiplicity is a special form of data analysis instability in which different analysis methods used on the same data, or different samples from the same population lead to different but apparently maximally predictive signatures. This phenomenon has far-reaching implications for biological discovery and development of next generation patient diagnostics and personalized treatments. Currently the causes and interpretation of signature multiplicity are unknown, and several, often contradictory, conjectures have been made to explain it. We present a formal characterization of signature multiplicity and a new efficient algorithm that offers theoretical guarantees for extracting the set of maximally predictive and non-redundant signatures independent of distribution. The new algorithm identifies exactly the set of optimal signatures in controlled experiments and yields signatures with significantly better predictivity and reproducibility than previous algorithms in human microarray gene expression datasets. Our results shed light on the causes of signature multiplicity, provide computational tools for studying it empirically and introduce a framework for in silico bioequivalence of this important new class of diagnostic and personalized medicine modalities

    Rotational master equation for cold laser-driven molecules

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    The equations of motion for the molecular rotation are derived for vibrationally cold dimers that are polarized by off-resonant laser light. It is shown that, by eliminating electronic and vibrational degrees of freedom, a quantum master equation for the reduced rotational density operator can be obtained. The coherent rotational dynamics is caused by stimulated Raman transitions, whereas spontaneous Raman transitions lead to decoherence in the motion of the quantized angular momentum. As an example the molecular dynamics for the optical Kerr effect is chosen, revealing decoherence and heating of the molecular rotation.Comment: 11 pages, 5 figures, to appear in Phys. Rev.

    Comparing factors affecting commencement and cessation of betel quid chewing behavior in Taiwanese adults

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    <p>Abstract</p> <p>Background</p> <p>Betel quid is the fourth most common used substance in the world after tobacco, alcohol and caffeine. Although factors related to betel quid chewing or cessation of behaviors were reported previously, few studies simultaneously compared both behaviors in the same population. In addition, it is essential to consider time-to-event concept, since the chance of developing or stopping habit may vary over time. The purpose of this study was to compare the risk factors for commencement and cessation of betel quid chewing behaviors in a time-to-event setting.</p> <p>Methods</p> <p>A stratified multi-stage cluster sampling with selection probabilities proportional to size (PPS) was designed for Taiwanese adults with aged 18 years old and above. Kaplan-Meier estimates and Cox proportional hazard regression models were used to compare and calculate the hazard rate ratios for related factors to commencement or cessation of chewing habits.</p> <p>Results</p> <p>In Taiwan, men had a higher betel quid chewing rate (M: 20.9%, W: 1.2%), but woman chewers had a lower cessation rate (M: 27.5%, W: 12.7%). The hazard rate ratio (HRR) of having chewing habit changed from 4.22 (men vs women) univariately to 1.38 multivariablely, which indicated gender differences were confounded by other factors. In multivariable analysis, the risk factors of gender, education and ethnicity were significantly associated with both starting and cessation of betel quid chewing behavior. The factors of occupation, cigarette smoking and alcohol drinking were only associated with starting habit.</p> <p>Conclusion</p> <p>Commencement or cessation of chewing behavior involves a scenario of time, hence it is preferable to use a time-to-event approach for the comparison. The cessation rates of betel quid chewing were decreasingly associated with the daily consumption of betel quid. Hence, reducing of daily amount in betel quid cessation program may be associated with future stopping habit.</p

    Evaluating predictive pharmacogenetic signatures of adverse events in colorectal cancer patients treated with fluoropyrimidines

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    The potential clinical utility of genetic markers associated with response to fluoropyrimidine treatment in colorectal cancer patients remains controversial despite extensive study. Our aim was to test the clinical validity of both novel and previously identified markers of adverse events in a broad clinical setting. We have conducted an observational pharmacogenetic study of early adverse events in a cohort study of 254 colorectal cancer patients treated with 5-fluorouracil or capecitabine. Sixteen variants of nine key folate (pharmacodynamic) and drug metabolising (pharmacokinetic) enzymes have been analysed as individual markers and/or signatures of markers. We found a significant association between TYMP S471L (rs11479) and early dose modifications and/or severe adverse events (adjusted OR = 2.02 [1.03; 4.00], p = 0.042, adjusted OR = 2.70 [1.23; 5.92], p = 0.01 respectively). There was also a significant association between these phenotypes and a signature of DPYD mutations (Adjusted OR = 3.96 [1.17; 13.33], p = 0.03, adjusted OR = 6.76 [1.99; 22.96], p = 0.002 respectively). We did not identify any significant associations between the individual candidate pharmacodynamic markers and toxicity. If a predictive test for early adverse events analysed the TYMP and DPYD variants as a signature, the sensitivity would be 45.5 %, with a positive predictive value of just 33.9 % and thus poor clinical validity. Most studies to date have been under-powered to consider multiple pharmacokinetic and pharmacodynamic variants simultaneously but this and similar individualised data sets could be pooled in meta-analyses to resolve uncertainties about the potential clinical utility of these markers

    Developmental changes in the role of different metalinguistic awareness skills in Chinese reading acquisition from preschool to third grade

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    Copyright @ 2014 Wei et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.The present study investigated the relationship between Chinese reading skills and metalinguistic awareness skills such as phonological, morphological, and orthographic awareness for 101 Preschool, 94 Grade-1, 98 Grade-2, and 98 Grade-3 children from two primary schools in Mainland China. The aim of the study was to examine how each of these metalinguistic awareness skills would exert their influence on the success of reading in Chinese with age. The results showed that all three metalinguistic awareness skills significantly predicted reading success. It further revealed that orthographic awareness played a dominant role in the early stages of reading acquisition, and its influence decreased with age, while the opposite was true for the contribution of morphological awareness. The results were in stark contrast with studies in English, where phonological awareness is typically shown as the single most potent metalinguistic awareness factor in literacy acquisition. In order to account for the current data, a three-stage model of reading acquisition in Chinese is discussed.National Natural Science Foundation of China and Knowledge Innovation Program of the Chinese Academy of Sciences

    Clinical features, predictive factors and outcome of hyperglycaemic emergencies in a developing country

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    <p>Abstract</p> <p>Background</p> <p>Hyperglycaemic emergencies are common acute complications of diabetes mellitus (DM) but unfortunately, there is a dearth of published data on this entity from Nigeria. This study attempts to describe the clinical and laboratory scenario associated with this complication of DM.</p> <p>Methods</p> <p>This study was carried out in DM patients who presented to an urban hospital in Nigeria with hyperglycaemic emergencies (HEs). The information extracted included biodata, laboratory data and hospitalization outcome. Outcome measures included mortality rates, case fatality rates and predictive factors for HEs mortality. Statistical tests used are <it>χ</it><sup>2</sup>, Student's t test and logistic regression.</p> <p>Results</p> <p>A total of 111 subjects with HEs were recruited for the study. Diabetes ketoacidosis (DKA) and hyperosomolar hyperglycaemic state (HHS) accounted for 94 (85%) and 17 (15%) respectively of the HEs. The mean age (SD) of the subjects was 53.9 (14.4) years and their ages ranged from 22 to 86 years. DKA occurred in all subjects with type 1 DM and 73 (81%) of subjects with type 2 DM. The presence of HSS was noted in 17 (19%) of the subjects with type 2 DM.</p> <p>Hypokalaemia (HK) was documented in 41 (37%) of the study subjects. Elevated urea levels and hyponatraemia were noted more in subjects with DKA than in those subjects with HHS (57.5%,19% vs 53%,18%). The mortality rate for HEs in this report is 20% and the case fatality rates for DKA and HHS are 18% and 35% respectively.</p> <p>The predictive factors for HEs mortality include, sepsis, foot ulceration, previously undetected DM, hypokalaemia and being elderly.</p> <p>Conclusion</p> <p>HHS carry a higher case fatality rate than DKA and the predictive factors for hyperglycaemic emergencies' mortality in the Nigerian with DM include foot ulcers, hypokalaemia and being elderly.</p

    Stringy Stability of Charged Dilaton Black Holes with Flat Event Horizon

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    Electrically charged black holes with flat event horizon in anti-de Sitter space have received much attention due to various applications in Anti-de Sitter/Conformal Field Theory (AdS/CFT) correspondence, from modeling the behavior of quark-gluon plasma to superconductor. Crucial to the physics on the dual field theory is the fact that when embedded in string theory, black holes in the bulk may become vulnerable to instability caused by brane pair-production. Since dilaton arises naturally in the context of string theory, we study the effect of coupling dilaton to Maxwell field on the stability of flat charged AdS black holes. In particular, we study the stability of Gao-Zhang black holes, which are locally asymptotically anti-de Sitter. We find that for dilaton coupling parameter α\alpha > 1, flat black holes are stable against brane pair production, however for 0 < α\alpha < 1, the black holes eventually become unstable as the amount of electrical charges is increased. Such instability however, behaves somewhat differently from that of flat Reissner-Nordstr\"om black holes. In addition, we prove that the Seiberg-Witten action of charged dilaton AdS black hole of Gao-Zhang type with flat event horizon (at least in 5-dimension) is always logarithmically divergent at infinity for finite values of α\alpha, and is finite and positive in the case α\alpha tends to infinity . We also comment on the robustness of our result for other charged dilaton black holes that are not of Gao-Zhang type.Comment: Fixed some confusions regarding whether part of the discussions concern electrically charged hole or magnetically charged one. No changes to the result

    Genetic and Mechanistic Evaluation for the Mixed-Field Agglutination in B3 Blood Type with IVS3+5G>A ABO Gene Mutation

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    Background: The ABO blood type B3 is the most common B subtype in the Chinese population with a frequency of 1/900. Although IVS3+5G.A (rs55852701) mutation of B gene has been shown to associate with the development of B3 blood type, genetic and mechanistic evaluation for the unique mixed-field agglutination phenotype has not yet been completely addressed. Methodology/Principal Findings: In this study, we analyzed 16 cases of confirmed B3 individuals and found that IVS3+5G.A attributes to all cases of B3. RT-PCR analyses revealed the presence of at least 7 types of aberrant B3 splicing transcripts with most of the transcripts causing early termination and producing non-functional protein during translation. The splicing transcript without exon 3 that was predicted to generate functional B3 glycosyltransferase lacking 19 amino acids at the N-terminal segment constituted only 0.9 % of the splicing transcripts. Expression of the B3 cDNA with exon 3 deletion in the K562 erythroleukemia cells revealed that the B3 glycosyltransferase had only 40 % of B1 activity in converting H antigen to B antigen. Notably, the typical mixed-field agglutination of B3-RBCs can be mimicked by adding anti-B antibody to the K562-B3 cells. Conclusions/Significance: This study thereby demonstrates that both aberrant splicing of B transcripts and the reduced B3 glycosyltransferase activity contribute to weak B expression and the mixed-field agglutination of B3, adding to th
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