The antibacterial activity and release of quaternary ammonium compounds in an orthodontic primer

The aim of this study was to evaluate the impact of 10 wt% benzalkonium chloride (TB-BAC) or 10 wt% cetylpyridinium chloride (TB-CPC) on the antimicrobial properties of the orthodontic adhesive primer, Transbond XT™ (TB). Antimicrobial activity was assessed using a zone of inhibition diffusion test and the release of the antimicrobial compounds was monitored by high performance liquid chromatography (HPLC). Shear bond strength (SBS) was tested using bovine enamel. Control, TB, specimens failed to demonstrate intrinsic antibacterial activity at 1, 7 and 14 days; whereas, TB-BAC and TB-CPC showed antibacterial effects at all times. HPLC analysis indicated no significant differences in the release behaviour of TB-BAC and TB-CPC (t-test, p > 0.05), except for the 7-day release which was higher for TB-BAC (p 0.05)

What happens when oral tuberculosis is not treated?

Pulmonary tuberculosis (TB) is the most important form of the disease, although infection may also occur by way of the intestinal tract, tonsils and skin. Oral lesions consist of persistent ulcers or granulomatous masses. A 50 year old man had been diagnosed “necrotising granulomatous inflammation” following a biopsy of a lesion on lower lip, 21 months before at a medical centre. A chest-X-ray had not been performed and he had not been given any advise in respect of treatment. He was admitted to the hospital with cough, sputum, weakness, weight loss and lesions on his lower lip. In radiology, it was detected that he had supraclavicular, submental, cervical, mediastinal lymphadenopathies, pulmonary infiltrations with cavities, thickening and roughness on left oropharengial tonsil, thickenning on inner parts of larynx and bilateral surrenal thickening. The biopsy of lesions on larynx, tonsil and epiglottis revealed “necrotising granulomatous inflammation” and histopathology supported TB infection. Sputum acid-fast bacilli was positive and culture was positive for Mycobacterium tuberculosis complex. Two months of combination treatment resulted in a gradual relief of the symptoms, radiological response, disappearing of neck swelling and healing of lesions on lip, tonsil and larynx. Although unusual oral cavity manifestations of TB are rare, clinicians should be aware of possible occurrance

The impact of Er:YAG laser enamel conditioning on the microleakage of a new hydrophilic sealant — UltraSeal XT® hydro™

UltraSeal XT® hydro™ is a new hydrophilic, light-cured, methacrylate-based pit and fissure sealant which has been developed by Ultradent Products, USA. The sealant is highly filled with a 53 wt.% mixture of inorganic particles which confer both thixotropy and radiopacity. The principal purpose of this study was to investigate the microleakage of UltraSeal XT® hydro™ as a function of different enamel etching techniques. The occlusal surfaces of sound, extracted human molars were either acid etched, Er:YAG laser irradiated or successively laser irradiated and acid etched. UltraSeal XT® hydro™ was applied to each group of teeth (n=10) which were subjected to a thermocycling process consisting of 2500 cycles between 5 and 50°C with a dwell time of 30s. Microleakage assessments were then carried out using 0.5 % fuchsin dye and optical microscopy. The microleakage score data were analysed using the Kruskal-Wallis, Mann–Whitney U test with Bonferroni adjustment. No significant differences in microleakage were noted between the individually acid etched and laser-irradiated groups (p>0.05); however, teeth treated with a combination of laser irradiation and acid etching demonstrated significantly lower microleakage scores (p<0.001). Electron microscopy with energy-dispersive X-ray analysis revealed that the mineral filler component of UltraSeal XT® hydro™ essentially comprises micrometre-sized particles of inorganic silicon-, aluminium- and barium-bearing phases. Laser etching increases the roughness of the enamel surface which causes a concentrated zoning of the filler particles at the enamel-sealant interface

Symmetry breaking and quantum correlations in finite systems: Studies of quantum dots and ultracold Bose gases and related nuclear and chemical methods

Investigations of emergent symmetry breaking phenomena occurring in small finite-size systems are reviewed, with a focus on the strongly correlated regime of electrons in two-dimensional semicoductor quantum dots and trapped ultracold bosonic atoms in harmonic traps. Throughout the review we emphasize universal aspects and similarities of symmetry breaking found in these systems, as well as in more traditional fields like nuclear physics and quantum chemistry, which are characterized by very different interparticle forces. A unified description of strongly correlated phenomena in finite systems of repelling particles (whether fermions or bosons) is presented through the development of a two-step method of symmetry breaking at the unrestricted Hartree-Fock level and of subsequent symmetry restoration via post Hartree-Fock projection techniques. Quantitative and qualitative aspects of the two-step method are treated and validated by exact diagonalization calculations. Strongly-correlated phenomena emerging from symmetry breaking include: (I) Chemical bonding, dissociation, and entanglement (at zero and finite magnetic fields) in quantum dot molecules and in pinned electron molecular dimers formed within a single anisotropic quantum dot. (II) Electron crystallization, with particle localization on the vertices of concentric polygonal rings, and formation of rotating electron molecules (REMs) in circular quantum dots. (III) At high magnetic fields, the REMs are described by parameter-free analytic wave functions, which are an alternative to the Laughlin and composite-fermion approaches. (IV) Crystalline phases of strongly repelling bosons. In rotating traps and in analogy with the REMs, such repelling bosons form rotating boson molecules (RBMs).Comment: Review article published in Reports on Progress in Physics. REVTEX4. 95 pages with 37 color figures. To download a copy with high-quality figures, go to publication #82 in http://www.prism.gatech.edu/~ph274cy

Improving of the angstrom-prescott model using harmonic analysis

The solar energy as one of the most important energy sources is investigated for effective use in a variety of areas. Especially, with the tendency of depletion of fossil fuel consumption as well as their greenhouse gas emissions leading to atmospheric pollution and, hence, global warming and climate change, the value of renewable energy sources and solar energy is increasing rapidly. In the solar energy prediction, the relationship between solar irradiation and sunshine duration plays the most dominant role. The aim of this study is to apply harmonic analysis, coupled with the classical Angström-Prescott equation, to solar irradiation and sunshine duration data for the extraction of its relevant relationship. Firstly, it helps to eliminate the periodicity from the measurement record and then the application of the Angström-Prescott model is applied, which is then tested and compared with the classical Angström-Prescott model based on the regression approach. The applications are achieved by use of measurements at the major city in the south-eastern Anatolian part of Turkey, namely, Diyarbakır. The improved model provides more successful and reliable outputs than the classical approach