Complex monolithic and InP hybrid integration on high bandwidth electro-optic polymer platform.

We report on the monolithic integration of multimode interference couplers, Bragg gratings, and delay-line interferometers on an electro-optic polymer platform capable of modulation directly at 100 Gb/s. We also report on the hybrid integration of InP active components with the polymer structure using the butt-coupling technique. Combining the passive and the active components, we demonstrate a polymer-based, external cavity laser with 17 nm tuning range and the optical assembly of an integrated 100 Gb/s transmitter, and we reveal the potential of the electro-optic polymer technology to provide the next generation integration platform for complex, ultra-high-speed optical transceivers.

Intubating laryngeal mask as a ventilatory device during percutaneous dilatational tracheostomy: a descriptive study.

BACKGROUND: We use an intubating laryngeal mask (ILM) in preference to an endotracheal tube (ETT) as the ventilatory device during percutaneous dilatational tracheostomy (PDT) to overcome potential problems such as difficult ventilation, accidental extubation, damage of the ETT or of the bronchoscope, and need for additional assistant to secure the airway. We report our experience with this method. METHODS: In this prospective observational study, PDT was performed using the ILM in 86 patients. The insertion of the ILM, the quality of ventilation, and the view of the tracheal puncture site were rated as: 'very good', 'good', 'difficult', and 'not possible with ILM'. RESULTS: The bronchoscope was not damaged during any case, and all PDTs were performed by two physicians, without the need for an additional assistant. PDTs with ILM were successful in 95% of the patients (n=82). The ratings were 'very good' or 'good' in 80% of cases with regards to ventilation, in 90% for identification of relevant structures and tracheal puncture site, and in 85% for the view inside the trachea during PDT. Tracheal re-intubation was required for inadequate ventilation with ILM in four patients. CONCLUSIONS: The advantages of this procedure were lack of damage to the bronchoscope, the need for two instead of three persons to perform the PDT, and the excellent view inside the trachea. We recommend the ILM as a standard device for ventilation during bronchoscope-guided PDT.

Perceiving unfairness in the family: cause or consequence of marital distress?

This research tests a model suggesting that marital distress leads individuals to scrutinize what is given and received in the relationship. This scrutiny elicits perceptions of unfairness that maintain or exacerbate marital distress. In a 3-panel longitudinal study tracking married couples across the transition to parenthood, both wives' and husbands' reports of marital conflict and wives' marital dissatisfaction at Time 1 positively predicted perceived unfairness of the allocation of household tasks at Time 2, controlling for earlier perceptions of unfairness. In addition, there was evidence of perceived unfairness of division of labor at Time 2 predicting marital conflict and marital dissatisfaction for wives at Time 3, controlling for earlier conflict and dissatisfaction. This model of relationship distress and perceptions of unfairness is contrasted with prior interpretations of links between perceived injustice and distress in relationships.

Why aren't indices of relationship costs always negatively related to indices of relationship quality?

Many researchers have made the seemingly straightforward predictions that relationship rewards will be positively, and relationship costs will be negatively, associated with indices of relationship quality. Existing literature supports the hypothesis for rewards, but evidence regarding costs is mixed. Depending on the study, indices of costs have been observed to be negatively associated, unassociated, and even positively associated with relationship quality. We argue that the mixed results may have been due in part to past cost measures tapping three separate constructs: (a) a partner's intentional poor behavior directed at the participant, (b) negative things associated with the relationship (but not caused by the partner's intentional behavior), and (c) behaving in such a manner as to meet a partner's needs-something which often may involve performing undesirable activities, foregoing desired opportunities, or giving up money, time, or goods. We believe the first two types of costs should be negatively associated with relationship quality. However, we argue that the last type, because it involves adhering to communal norms (Clark & Mills, 1979,1993) will often tend to be either negligibly or even positively associated with relationship quality. In two studies the occurrence of these three categories of events in close relationships as well as the quality of those relationships were measured. The overall pattern of results supports our specific hypotheses as well as the general idea that a lack of conceptual clarity regarding "costs" has contributed to the current mixed nature of our literature on links between relationship costs and relationship quality.

A study of the ability of an in situ remineralization model to differentiate between the effects of two fluoride dentifrices that produced significantly different clinical caries results.

The purpose of this study was to determine whether an in situ remineralization model was able to show a difference in the effects of two dentifrices of different fluoride concentrations and significantly different clinical efficacies. Three dentifrices were tested in a double-blind, cross-over study design. The products contained 0 ppm F, 250 ppm F, or 1000 ppm F from sodium fluoride and were formulated with a silica base according to the formulations used in a human caries trial (Koch et al., 1990). Nineteen subjects each carried three or four thin sections of enamel in their partial dentures. The thin sections, containing artificial caries lesions, were covered with a steel mesh to provide space for plaque formation and then brushed in situ three times daily with the dentifrices. Following the two-week treatment periods, the specimens were removed from the dentures and analyzed for changes in mineral content. The findings showed that the placebo dentifrice (0 ppm F) resulted in 56.8 +/- 74.3% demineralization, the 250-ppm-F dentifrice produced 12.9 +/- 41.3% demineralization, thereby showing partial caries protection, and the 1000-ppm-F dentifrice produced 17.3 +/- 32.1% remineralization. Linear regression analysis showed that the percent remineralization was significantly related to the fluoride concentration in the dentifrice (p less than 0.001). The 250-ppm-F dentifrice was also significantly less effective than the 100-ppm-F dentifrice (p = 0.04, one-tailed Fisher Protected LSD test). These findings are in accord with the human caries trial and support the use of the present in situ remineralization model for prediction of the anticaries efficacy of fluoride dentifrice products.

Findings from an in situ thin-section sandwich model for evaluating cariogenic and anti-cariogenic activity.

This report summarizes the findings from eight individual remineralization studies that used the thin-section sandwich model. This model uses thin sections of human enamel (or dentin) containing caries-like lesions sandwiched between sheets of thin plastic which are then implanted into the buccal surfaces of molars in removable partial mandibular dentures. Toothbrushing with a sodium fluoride-positive control dentifrice for two-week periods always produced positive remineralization of the lesions, and similar use of a placebo always produced mean mineral loss. In most studies, the difference was significant at p less than 0.01. However, variation among specimens placed within an individual mouth were often large and even included cases where one lesion gained mineral while a closely adjacent lesion lost mineral. Similarly, mean mineral changes produced by an individual subject were not consistent from study to study and ranged from net demineralization in one study to net remineralization in another study. Nevertheless, mean mineral changes from all eight studies showed that all subjects produced more remineralization than demineralization when using a sodium fluoride-positive control dentifrice. Data are presented showing remineralization of thin-section lesions from a number of other fluoride and non-fluoride dentifrices and mouthrinses and showing that a product with reduced anti-caries activity (as measured by several tests) also resulted in reduced remineralization by the thin-section model.

Remineralization and demineralization in situ from a triclosan/co-polymer/fluoride dentifrice.

An in situ study was conducted to evaluate the effect of a dentifrice containing 1100 ppm F (NaF) and triclosan, an anti-plaque agent, on remineralization of artificially-formed caries lesions in thin sections of human enamel. The thin sections were placed in mandibular partial dentures of 15 subjects and covered with a steel mesh to provide an area for plaque accumulation. The subjects brushed their teeth and dentures three times daily for two-week periods in a cross-over design, after which the specimens were removed and analyzed by quantitative microradiography for changes in mineral content. Results showed that lesions treated with the triclosan-fluoride product were remineralized 18.0 +/- 23.4% compared with 19.0 +/- 32.3% from a 1100-ppm F (NaF) positive control. Use of a placebo dentifrice resulted in 71.9% demineralization. The findings showed that triclosan neither enhanced nor interfered with the promotion of remineralization by fluoride.

Effect of a steel mesh and human dental plaque on fluoride uptake in vitro.

Blocks of bovine enamel, covered with a steel mesh or a steel mesh plus plaque or with neither, were treated in vitro with a 20% slurry of a fluoride dentifrice for 1 h. An initial experiment showed that fluoride in blocks without mesh or plaque increased significantly, whereas fluoride in blocks covered with a steel mesh harboring intraorally accumulated plaque did not. A follow-up experiment showed that enamel blocks covered with the mesh but without plaque acquired a small amount of fluoride, but significantly less than the blocks without mesh. These experiments indicate that covering enamel specimens with mesh, as is done during in situ experiments, may significantly influence the transport of fluoride to the enamel and, therefore, the amount of fluoride acquired by the specimens and perhaps the degree of de- or remineralization. They also suggest that the fluoride distribution to some areas of the natural dentition may be inadequate.

Evaluation of the effects of a pyrophosphate-fluoride anticalculus dentifrice on remineralization and fluoride uptake in situ.

Enamel slabs and thin sections with artificially formed caries lesions were placed in the removable dentures of 15 subjects who brushed them three times daily for 2 weeks with a 1.3% pyrophosphate/1,100 ppm F/1.5% Gantrez dentifrice, a 1,100-ppm F dentifrice without pyrophosphate or Gantrez, or a placebo dentifrice in a double-blind, crossover study. Analysis of the thin sections by quantitative microradiography showed that the pyrophosphate/F dentifrice remineralized the lesions 15.9% (p less than 0.05) and the fluoride dentifrice 11.2%, whereas the placebo produced 4.4% demineralization. Fluoride uptake by the enamel slabs was similar for both fluoride dentifrices and significantly greater from the placebo dentifrice (p less than 0.05). The findings suggest that the anticaries mechanisms of fluoride include not only the prevention of demineralization, but also the promotion of remineralization.

Effect of two sodium fluoride dentifrices on fluoride uptake and remineralization in situ.

Two dentifrices containing 1100 ppm F from sodium fluoride in silica bases were compared to a placebo dentifrice in an in situ remineralization and fluoride uptake study. Fifteen subjects brushed artificially-formed caries lesions in 60 thin enamel sections and 30 enamel blocks with each dentifrice in a double-blind, randomized, cross-over study design. Analysis of the thin sections by quantitative microradiography before and after exposure to toothbrushing showed that the fluoride dentifrices produced 18.3% and 7.1% remineralization whereas use of the placebo resulted in 10.3% demineralization. The differences between all three dentifrices were statistically significant. Fluoride concentrations at the surface of the lesion increased from approximately 700 ppm F in untreated specimens to approximately 1800 ppm F in specimens treated with either of the two fluoride dentifrices. These data suggest that formulation differences may affect the anticaries activity of a dentifrice without being reflected by fluoride deposition.

The effect of plaque thickness on progression of artificial caries lesion formation in situ.

Eighty thin enamel sections with artificially-formed caries lesions were implanted in the buccal surfaces of molars (in the removable partial dentures of ten subjects) and covered with a steel mesh for plaque accumulation to occur. The mesh was placed in contact with the enamel surface in half the lesions and 0.5 mm above the lesions in the other half, thus facilitating formation of thin and thick plaque samples. Following two-week use of a non-fluoride dentifrice, the lesions were analyzed for mineral change by quantitative microradiography. Significant mineral was lost from lesions in both groups, but the loss was twice as large in the thick-plaque group. These findings are important to in vivo remineralization models, since they show that plaque thickness should be controlled for minimization of variation.

The effects of 1% pyrophosphate and 0.02% sodium fluoride on artificial caries lesions in vivo.

We evaluated the potential of a pyrophosphate-fluoride solution to affect the remineralizing-demineralizing equilibrium, i.e., caries-inhibiting/-promoting effects on enamel in vivo. Fifteen subjects carried dentin blocks and enamel thin sections with artificial caries lesions in removable partial dentures for periods of two weeks, during which time they rinsed twice daily in a double-blind, randomized cross-over design with solutions containing (a) 90 ppm F, (b) 90 ppm F and 1% pyrophosphate, or (c) no active agents (placebo). A severe cariogenic challenge provided to the lesions by plaque under a stainless steel mesh cover resulted in the placebo-treated lesions losing 70.2% +/- 72.1% mineral. The pyrophosphate rinse with fluoride held the mineral loss to only 28.1 +/- 52.8%, while the fluoride rinse without pyrophosphate held the loss to 24.2 +/- 50.1%. The differences between the fluoride and placebo results were significant (p less than 0.01), but the difference between the two fluoride groups was not. A large amount of fluoride was deposited in the dentin lesions. In the surface layer, the concentration was increased from 1000 ppm F to more than 2300 ppm F by both fluoride treatments. The concentration of fluoride in both groups of fluoride-treated lesions further increased to more than 3500 ppm F in the approximate center of the lesion before declining in deeper layers toward the level found in the placebo-treated group. The findings from both mineral change and fluoride uptake phases of this study show that in the presence of 90 ppm F, 1% pyrophosphate did not promote demineralization of artificial caries lesions.