Finnish Dentists Find Smoking Cessation Important but Seldom Offer Practical Support for Their Patients.

OBJECTIVES: To investigate Finnish dentists' smoking cessation related attitudes, consultation practices and familiarity with the local treatment guideline on smoking cessation. BASIC RESEARCH DESIGN: An online questionnaire was sent to 1740 dentists, which corresponds to 39% of dentists in Finland. A total of 456 dentists responded (response rate 26%), of whom 435 (95%) were clinicians. The dentists' smoking cessation practices were also compared to ones reported in a previous study in Finnish physicians. RESULTS: Dentists found smoking cessation important and often discussed and recommended quitting to the patients, but concrete withdrawal actions were seldom provided. The local treatment guideline on smoking cessation was actively utilized by 36% of the dentists. Adherence to the guideline was associated with higher rates of smoking cessation activities and success in them. Smoking cessation activity among dentists was significantly lower than in Finnish physicians. In accordance with the literature, among dentists, the most common barriers for smoking cessation were lack of time (44%) and education (42%). CONCLUSION: Although smoking cessation is discussed with patients, dentists are less active in taking concrete actions to support the patient on withdrawal. Adherence to the local treatment guideline was associated with better capabilities in dealing with tobacco withdrawal and a more active role in smoking cessation. The results suggest that more education on the local smoking cessation treatment guideline and cessation intervention is needed in order to overcome the remaining barriers to promoting effective smoking cessation in dental practice.

Explosions of xenon clusters in ultraintense femtosecond x-ray pulses from the LCLS free electron laser.

Explosions of large Xe clusters ( ~ 11,000) irradiated by femtosecond pulses of 850 eV x-ray photons focused to an intensity of up to 10(17) W/cm(2) from the Linac Coherent Light Source were investigated experimentally. Measurements of ion charge-state distributions and energy spectra exhibit strong evidence for the formation of a Xe nanoplasma in the intense x-ray pulse. This x-ray produced Xe nanoplasma is accompanied by a three-body recombination and hydrodynamic expansion. These experimental results appear to be consistent with a model in which a spherically exploding nanoplasma is formed inside the Xe cluster and where the plasma temperature is determined by photoionization heating.

Explosion of xenon clusters driven by intense femtosecond pulses of extreme ultraviolet light.

The explosions of large xenon clusters irradiated by intense, femtosecond extreme ultraviolet pulses at a wavelength of 38 nm have been studied. Using high harmonic generation from a 35 fs laser, clusters have been irradiated by extreme ultraviolet pulses at intensity approaching 10;{11} W/cm;{2}. Charge states up to Xe8+ are observed, states well above those produced by single atom illumination, indicating that plasma continuum lowering is important. Furthermore, the kinetic energy distribution of the exploding ions is consistent with a quasineutral hydrodynamic expansion, rather than a Coulomb explosion.

Resonant frequency-domain interferometry via third-harmonic generation.

A method for measuring resonances using a combination of third-harmonic generation and frequency-domain interferometry is described and demonstrated in an index-matched dielectric material. The phase of the third-harmonic spectrum of a pulse generated from a resonant NdAlO(3) thin film and a temporally displaced sapphire substrate pulse was measured by analyzing the spectral interference pattern. The appropriate combination of substrate and film signals was obtained by translating the sample through the laser focus while observing the third-harmonic intensity.

Calibration of a computer-controlled precision wavemeter for use with pulsed lasers.

The design of a pulsed wavemeter to monitor the high-precision tuning of pulsed (as well as cw) laser sources is presented. This device is developed from a combination of silver-coated Fabry-Perot etalons with various plate spacings. These etalons provide stepwise refinement of the wavelength to be measured. The wavemeter is controlled by a computer through a CAMAC interface, which measures the absolute wavelength in the visible with an accuracy of 2 parts in 10(8). The time required for data acquisition and computation to measure the refined wavelength with a single 2-MHz CPU is less than 100 ms. We describe the calibration of the instrument over the wavelength range 400-850 nm. We obtain the required calibration lines by locking lasers on hyperfine transitions of iodine, uranium, rubidium, and cesium. Methods to reduce the number of calibration lines required for calibration of the system are described. The expected wavelength-dependent phase shift of the silver coatings is compared with that measured for the etalon following calibration. The differences are larger than expected because of either optical aberations or the use of centroids to measure the fringe position.

Precisely tunable, narrow-band pulsed dye laser.

Anarrow-band, precisely tunable dye laser pumped by an injection-seeded YAG laser is described. The laser achieves an output of 100 mJ/pulse and 40% efficiency when one uses Rhodamine 6G dyes. The output pulse is Gaussian both in time and spatial profile. The laser oscillator employs an intracavity étalon that is repetitively pressure scanned over one free spectral range while the grating successively steps to consecutive étalon modes. We pressure scanned the étalon under computer control using a bellows. Methods are described for calibrating the tuning elements for absolute precision. We demonstrated that the laser has an absolute precision of ±0.4 pm over a 1.0-nm scan. This accuracy is achievable over the wavelength range of a dye.

Techniques for measuring small changes in the intensity of a pulsed laser.

Several techniques are described that compensate for the pulse-to-pulse laser fluctuations that occur when small absorption or gain measurements are taken with pulsed lasers. The best approach tested used two matched diodes that were mounted in a bridge circuit with their bias batteries. One diode was illuminated by a single beam, and a second was illuminated by a reference beam. The bridge circuit output forms the difference in the two laser intensities. Using pulsed lasers with 8-ns widths, we observed that the error in subtraction was 0.01% of the pulse area. This was only 1.5 times the shot noise of the pulses. The technique is examined for application to Raman-induced Kerr-effect spectroscopy, in which difficulties arise because of the use of polarization-sensitive detection.

Multipass prism monochromator for coherent Raman spectroscopy.

A multipass, Brewster prism monochromator that is an effective laser beam separator is described. Fourteen passes through the prism of the monochromator produce a resolution of 4 cm(-1) with a throughput of 63%. Larger throughputs are obtained for fewer passes and a poorer resolution. The device is tunable and has an extinction coefficient of 2 x 10(-8) at a detuning of 200 cm(-1). It promises to be an important tool for coherent Raman spectroscopy.