Lung cancer in Chinese women: Evidence for an interaction between tobacco smoking and exposure to inhalants in the indoor environment

10.1289/ehp.0901587Environmental Health Perspectives11891257-126

Effects of columnar disorder on flux-lattice melting in high-temperature superconductors

The effect of columnar pins on the flux-lines melting transition in high-temperature superconductors is studied using Path Integral Monte Carlo simulations. We highlight the similarities and differences in the effects of columnar disorder on the melting transition in YBa$_2$Cu$_3$O$_{7-\delta}$ (YBCO) and the highly anisotropic Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ (BSCCO) at magnetic fields such that the mean separation between flux-lines is smaller than the penetration length. For pure systems, a first order transition from a flux-line solid to a liquid phase is seen as the temperature is increased. When adding columnar defects to the system, the transition temperature is not affected in both materials as long as the strength of an individual columnar defect (expressed as a flux-line defect interaction) is less than a certain threshold for a given density of randomly distributed columnar pins. This threshold strength is lower for YBCO than for BSCCO. For higher strengths the transition line is shifted for both materials towards higher temperatures, and the sharp jump in energy, characteristic of a first order transition, gives way to a smoother and gradual rise of the energy, characteristic of a second order transition. Also, when columnar defects are present, the vortex solid phase is replaced by a pinned Bose glass phase and this is manifested by a marked decrease in translational order and orientational order as measured by the appropriate structure factors. For BSCCO, we report an unusual rise of the translational order and the hexatic order just before the melting transition. No such rise is observed in YBCO.Comment: 32 pages, 13 figures, revte

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Clinical diagnosis and management strategies of amelogenesis imperfectavariants.

Amelogenesis imperfecta (AI) is a group of inherited disorders primarily affecting dental enamel. Variants of AI generally are classified as hypoplastic, hypocalcified, or hypomaturation types based on the primary enamel defect. The aim of this study was to analyze the clinical presentations, diagnostic features, and clinical complications of different variants of AI. Thirty-two patients from 17 families with several subtypes of AI were studied. The results showed that distinctive clinical features may be observed in each variant. However, all AI patients suffered common clinical problems of poor esthetics, teeth sensitivity, and loss of occlusal vertical dimension. The mildest problems were found in the pitted hypoplastic type whereas the most severe problems were encountered in the hypocalcified type of AI. Management strategies include composite resin veneers and jacket crowns for anterior teeth as well as steel crowns for posterior teeth. Knowledge of the clinical features and dental complications of each variant of AI helps in the diagnosis of the condition and allows institution of early preventive measures

Comparison of ultrasonic and mechanical cleaning of primary root canals using a novel radiometric method.

Although ultrasound is employed increasingly as an adjunct to biomechanical preparation in clinical endodontics for adult teeth, there have been no previous investigation of this technique for primary teeth. This investigation studied the efficacy of ultrasonication compared with mechanical cleaning in primary root canals using a novel radiometric method. The results indicated that in multiple-rooted teeth, ultrasonication with an endosonic file for 3 min was able to remove 81.1% of inoculated bacteria, compared with only 65.2% using conventional filing. A combination of mechanical filing followed by ultrasonication produced the best results, with greater than 95% bacteria removed. The results show that ultrasonication may be useful for primary teeth endodontics

The effects of dyadic combinations of endodontic medicaments on microbial growth inhibition.

In recent years dyadic combinations of endodontic medicaments have been used increasingly in clinical pediatric dentistry with little regard to the possibility of pharmacological antagonism of the components. In this investigation, a microbial growth inhibition assay was used to determine changes in antimicrobial activity in dyadic mixtures of endodontic medicaments. The combinations assayed were Ledermix (corticosteroid-antibiotic) and Calyxl (calcium hydroxide), Ledermix and Kri (iodoform), Kri and Calyxl, and formocresol and eugenol. All these compounds have antibacterial activity when used individually. In the dyadic combinations assayed, results showed that adding calcium hydroxide to another antibiotic preparation has deleterious effects on growth inhibition, and combining any two antimicrobial medicaments produces no additive or synergistic effects. It is concluded that it may be clinically advantageous to use endodontic medicaments in the dyadic combinations shown in this investigation

Clinical diagnosis of enamel defects: Pitfalls and practical guidelines

Changes in enamel during its development are permanently recorded, and commonly present as either demarcated opacity, diffuse opacity, or enamel hypoplasia. Developmental enamel defects may provide clues regarding their aetiology, and this may have application in clinical dentistry, dental epidemiology and anthropology. However, the usefulness of these applications may be hampered by many pitfalls encountered in the detection and diagnosis of developmental enamel defects. The defects may be masked by saliva, dental plaque, and incorrect lighting. In addition, confounding effects of post-eruptive changes such as dental caries, attrition, and traumatic loss of tooth structure may impair the detection of developmental enamel defects. The non-specificity of appearance of enamel defects may make aetiologic diagnosis of enamel hypoplasia difficult. Furthermore, difficulty is often encountered in the relative timing of events in enamel hypoplasia, due to limited data on the chronology of development of the human dentition. In this review, pitfalls in the clinical assessment of enamel defects are discussed, and guidelines to overcome some of these difficulties are presented

The effect of medical therapy on dentin formation in vitamin D-resistant rickets.

Vitamin D-resistant rickets (VDRR) is one of the most common forms of rickets in developed countries today. Widely practiced medical treatment regimens usually include replacing phosphorus and calcium lost through urination. In this study, 20 teeth from five patients with varying grades of dental manifestation of VDRR were examined to relate the institution of medical therapy with any observed improvement of dentin calcification. In all the teeth examined, there was no correlation between the time of appearance of dentin changes and the commencement of medical therapy. Furthermore, in several teeth from the patients with Grade III severity, there were no signs of improvement in dentin calcification even after prolonged medical therapy. This study suggests that current medical treatment of VDRR has no beneficial effect on the dental structures and dentists should not rely on medical treatment to correct dental calcification problems

The effects of acid-etching on enamel from different clinical variants of amelogenesis imperfects: An SEM study

Successful bonding of resins to teeth affected by amelogenesis imperfecta (AI) may be highly dependent on how the enamel responds to acid etching. The aim of this study was to determine, using scanning electron microscopy (SEM), the types of etching pattern achieved with 37% phosphoric acid on dental enamel of 5 clinical variants of AI, namely, pitted hypoplastic, smooth hypoplastic, X-linked (male), X-linked (female), and hypomineralized.A normal premolar and primary molar from two healthy patients were used as controls. The enamel was scanned before and after acid etching for 1 min. In the normal, control teeth, the three classical etching patterns were produced: type 1, in which the prism cores are preferentially removed; type 2, in which the prism peripheries are removed, and type 3 in which the removal of enamel does not relate to prism structure.In the normal primary molar, patterns of types 2 and 3 were generally produced. In the AI teeth, the effects of acid etching reflected the clinical variant of AI. All three etch patterns were observed in the enamel surrounding the pits in the pitted type of AI and in the bands of normal enamel in the female with X-linked AI, as well as in the hypomineralized variant. In contrast, no typical etch patterns could be detected in the enamel from the male patient with X-linked variant, as well as from the enamel affected by the smooth hypoplastic variant.The lack of typical etching patterns in these variants may be the result of abnormal prism structure, or the standard etching time and/or acid concentration may be inappropriate for the abnormal enamel. The results of this study may have useful applications in the restoration of teeth affected by AI