Effect of 457 nm Diode-Pumped Solid State Laser on the Polymerization Composite Resins: Microhardness, Cross-Link Density, and Polymerization Shrinkage

Objective: The purpose of the present study was to test the usefulness of 457 nm diode-pumped solid state (DPSS) laser as a light source to cure composite resins. Materials and methods: Five different composite resins were light cured using three different light-curing units (LCUs): a DPSS 457 nm laser (LAS), a light-emitting diode (LED), and quartz-tungsten-halogen (QTH) units. The light intensity of LAS was 560 mW/cm2, whereas LED and QTH LCUs was ∼900 mW/cm2. The degree of polymerization was tested by evaluating microhardness, cross-link density, and polymerization shrinkage. Results: Before water immersion, the microhardness of laser-treated specimens ranged from 40.8 to 84.7 HV and from 31.7 to 79.0 HV on the top and bottom surfaces, respectively, and these values were 3.3–23.2% and 2.9–31.1% lower than the highest microhardness obtained using LED or QTH LCUs. Also, laser-treated specimens had lower top and bottom microhardnesses than the other LCUs treated specimens by 2.4–19.4% and 1.4–27.8%, respectively. After ethanol immersion for 24 h, the microhardness of laser-treated specimens ranged from 20.3 to 63.2 HV on top and bottom surfaces, but from 24.9 to 71.5 HV when specimens were cured using the other LCUs. Polymerization shrinkage was 9.8–14.7 μm for laser-treated specimens, and these were significantly similar or lower (10.2–16.0 μm) than those obtained using the other LCUs. Conclusions: The results may suggest that the 457 nm DPSS laser can be used as a light source for light-curing dental resin composites

Oxygen Partial Pressure during Pulsed Laser Deposition: Deterministic Role on Thermodynamic Stability of Atomic Termination Sequence at SrRuO3/BaTiO3 Interface

With recent trends on miniaturizing oxide-based devices, the need for atomic-scale control of surface/interface structures by pulsed laser deposition (PLD) has increased. In particular, realizing uniform atomic termination at the surface/interface is highly desirable. However, a lack of understanding on the surface formation mechanism in PLD has limited a deliberate control of surface/interface atomic stacking sequences. Here, taking the prototypical SrRuO3/BaTiO3/SrRuO3 (SRO/BTO/SRO) heterostructure as a model system, we investigated the formation of different interfacial termination sequences (BaO-RuO2 or TiO2-SrO) with oxygen partial pressure (PO2) during PLD. We found that a uniform SrO-TiO2 termination sequence at the SRO/BTO interface can be achieved by lowering the PO2 to 5 mTorr, regardless of the total background gas pressure (Ptotal), growth mode, or growth rate. Our results indicate that the thermodynamic stability of the BTO surface at the low-energy kinetics stage of PLD can play an important role in surface/interface termination formation. This work paves the way for realizing termination engineering in functional oxide heterostructures.Comment: 27 pages, 6 figures, Supporting Informatio

New Heteroleptic Cobalt Precursors for Deposition of Cobalt-Based Thin Films

A new series of heteroleptic complexes of cobalt were synthesized using aminoalkoxide and ??-diketonate ligands. The complexes, [Co(dmamp)(acac)]2 (3), [Co(dmamp)(tfac)]2 (4), [Co(dmamp)(hfac)]2 (5), [Co(dmamp)(tmhd)]2 (6), and [Co(dmamb)(tmhd)]2 (7), were prepared by two-step substitution reactions and studied using Fourier transform infrared spectroscopy, mass spectrometry, elemental analysis, and thermogravimetric analysis (TGA). Complexes 3-7 displayed dimeric molecular structures for all of the complexes with cobalt metal centers interconnected by ??2-O bonding by the alkoxy oxygen atom. TGA and a thermal study of the complexes displayed high volatilities and stabilities for complexes 6 and 7, with sublimation temperatures of 120 ??C/0.5 Torr and 130 ??C/0.5 Torr, respectively

Comparative study of dimer vacancies and dimer-vacancy lines on Si(001) and Ge(001)

Although the clean Si(001) and Ge(001) surfaces are very similar, experiments to date have shown that dimer-vacancy (DV) defects self-organize into vacancy lines (VLs) on Si(001), but not on Ge(001). In this paper, we perform empirical-potential calculations aimed at understanding the differences between the vacancies on Si(001) and Ge(001). We identify three energetic parameters that characterize the DVs on the two surfaces: the formation energy of a single DV, the attraction between two DVs in adjacent dimer rows, and the strain sensitivity of the formation energy of DVs and VLs. At the empirical level of treatment of the atomic interactions (Tersoff potentials), all three parameters are favorable for the self-assembly of DVs on the Si(001) surface rather than on Ge(001). The most significant difference between the defects on Si(001) and on Ge(001) concerns the formation energy of single DVs, which is three times larger in the latter case. By calculating the strain-dependent formation energies of DVs and VLs, we propose that the experimental observation of self-assembly of vacancies on clean Ge(001) could be achieved by applying compressive strains of the order of 2%.Comment: 3 tables, 4 figures, to appear in Surface Scienc

Retropharyngeal abscess coinfected with and after rhinoviral infection in a 1-month-old infant

A retropharyngeal abscess is a rare disease entity in young infants but can develop after nasopharyngeal viral infection. Group B Streptococcus and Staphylococcus aureus are the most common pathogens in young infants, however, Mycobacterium tuberculosis is very rare. We report the case of retropharyngeal abscess and coinfection with S. aureus and M. tuberculosis in a very young infant presenting with respiratory symptoms due to upper airway obstruction. Usually tuberculous retropharyngeal abscesses are caused by the direct invasion of the bacteria from the spine via anterior longitudinal ligament of the spine. However, in this case, no associated spinal disease was observed

Early Compliance and Efficacy of Sublingual Immunotherapy in Patients with Allergic Rhinitis for House Dust Mites

Objectives. Sublingual immunotherapy (SLIT) has recently received much attention around the world as a treatment for allergic rhinitis. This study aimed to investigate the efficacy and adverse effects of SLIT in Korean patients with allergic rhinitis caused by house dust mites. The treatment compliance and the patient satisfaction with SLIT were also assessed. Methods. The patients who were sensitized to Dermatophagoides pteronyssinus and Dermatophagoides farinae and who started SLIT between November 2007 and July 2008 were included in this study. The symptom questionnaires, which included items on rhinorrhea, sneezing, nasal obstruction, itchy nose, olfactory disturbance, eye discomfort and sleep disturbance, were obtained before and 6 months after SLIT. The patient satisfaction and the adverse effects were also investigated. Results. One hundred forty-two patients started SLIT and 98 of them continued SLIT for 6 months or more. Ninety-two of the 98 patients completed the questionnaires. The duration of receiving SLIT was 9.8 months on average (range, 6 to 13 months). All the symptoms of allergic rhinitis were improved with SLIT. Forty-five percent of the patients were satisfied for SLIT, while 12% were unsatisfied. The incidence of adverse effects was 12% during maintenance therapy, although it was 48% during the up-dosing phase. The drop-out rate of SLIT was 31.0%. Conclusion. The subjective symptoms were improved with SLIT in Korean patients with allergic rhinitis for house dust mites. Yet the drop out rate was high despite of the symptomatic improvement.Roder E, 2008, CLIN EXP ALLERGY, V38, P1659, DOI 10.1111/j.1365-2222.2008.03060.xEsch RE, 2008, CURR OPIN OTOLARYNGO, V16, P260Frew AJ, 2008, NEW ENGL J MED, V358, P2259BOUSQUET J, 2008, ALLERGY S, V86, P8Eifan AO, 2007, ALLERGY, V62, P567, DOI 10.1111/j.1398-9995.2006.01301.xDunsky EH, 2006, ALLERGY, V61, P1235, DOI 10.1111/j.1398-9995.2006.01137.xAntico A, 2006, ALLERGY, V61, P1236, DOI 10.1111/j.1398-9995.2006.01155.xDahl R, 2006, J ALLERGY CLIN IMMUN, V118, P434, DOI 10.1016/j.jaci.2006.05.003Durham SR, 2006, J ALLERGY CLIN IMMUN, V117, P802, DOI 10.1016/j.jaci.2005.12.1358Passlacqua G, 2006, J ALLERGY CLIN IMMUN, V117, P946, DOI 10.1016/j.jaci.2005.12.1312Canonica GW, 2006, ALLERGY, V61, P20PASSALACQUA G, 2006, INFLAMM ALLERGY DRUG, V5, P43RIENZO VD, 2005, CLIN EXP ALLERGY, V35, P560KIM DY, 2004, KOREAN J OTOLARYNGOL, V47, P132WILSON DR, 2003, COCHRANE DB SYST REV, P2893NUHOGLU Y, 2003, J INVESTIG ALLERGOL, V17, P375Lombardi C, 2001, ALLERGY, V56, P989Guez S, 2000, ALLERGY, V55, P369, DOI 10.1034/j.1398-9995.2000.00413.xPurello-D`Ambrosio F, 1999, ALLERGY, V54, P968Pradalier A, 1999, ALLERGY, V54, P819Durham SR, 1996, J ALLERGY CLIN IMMUN, V97, P1356CASANOVAS M, 1994, J INVEST ALLERG CLIN, V4, P305

Effect of Thermal Preconditioning Before Excimer Laser Photoablation

The purposes of this study were to assess the expression patterns of heat shock proteins (Hsps), after eyeball heating or cooling, and to elucidate their relationships with corneal wound healing and intraocular complications after excimer laser treatment. Experimental mice were grouped into three according to local pretreatment type: heating, cooling, and control groups. The preconditioning was to apply saline eyedrops onto the cornea prior to photoablation. Following photoablation, we evaluated corneal wound healing, corneal opacity and lens opacity. Hsp expression patterns were elucidated with Western blot and immunohistochemical staining. The heating and cooling groups recovered more rapidly, and showed less corneal and lens opacity than the control group. In the heating and cooling groups, there were more expressions of Hsps in the cornea and lens than in the control group. These results were confirmed in the Hsp 70.1 knockout mouse model. Our study showed that Hsps were induced by the heating or cooling preconditioning, and appeared to be a major factor in protecting the cornea against serious thermal damage. Induced Hsps also seemed to play an important role in rapid wound healing, and decreased corneal and lens opacity after excimer laser ablation