Promoting Executive Function Skills in Preschoolers Using a Play-Based Program

In recent years, play has been shown to be a powerful means to enhance learning and brain development. It is also known that through play children enhance their executive function (EF) skills. Furthermore, well-developed EF in preschoolers has been shown to be an important predictor for later academic and life success. Armed with this information a program, Building Brains and Futures (BBF), for developing EF through play was designed for 3–5-year-old. The program consisted of 10 simple, fun, and interactive games selected to enhance various facets of EF. The 10 games included were: dimensional change card sort, lips and ears, block building, musical freeze, opposites, pretend play, red light/green light, shared project, Simon says, and wait for it. The program was implemented with a group of children shown to have challenges with respect to kindergarten readiness. The approach was first, to build adult capability by sharing knowledge of brain development, EF, and the importance of play with educators, caregivers, and parents. Second, to build skills in delivering the program in the school setting. Children engaged with the program of games for a minimum of 6 weeks. Their performance on a battery of direct measures of EF, language, and motor skills, were recorded before and after the program. The results showed improvement in all three domains. In addition, adopters of the BBF program reported it was easily and successfully integrated into their existing preschool curricula. The importance of intentional adult directed play in building developmental learning, including EF, is discussed.

Mechanical and Physical Properties of Differently Alloyed Sintered Steels as a Function of the Sintering Temperature

In this paper, the effect of processes occurring during the sintering of four powder metallurgy steel grades on the resulting properties were investigated. This included three grades prepared from plain iron powder with admixed graphite, one grade alloyed also with elemental copper and another with Fe-Mn-Si masteralloy. One further grade was prepared from Cr-Mo pre-alloyed powder with admixed graphite. The effect of the sintering processes was examined in the temperature range of 700–1300 °C in an inert atmosphere (Ar). In order to study oxygen removal, DTA/TG runs linked with mass spectrometry (MS) as well as C/O elemental analysis were performed. Charpy impact tests and fractography studies were performed to study the effect of the temperature on the formation and growth of sintering contacts. Characterization also included metallography, dimensional change, sintered density, and hardness measurements to describe the dissolution of carbon and alloying elements during the process. Physical properties that were measured were electrical conductivity and coercive force. The results showed that, in all steels, the reduction of oxides that occur during the heating stage plays a key role in the formation and growth of the sintering contacts as well as in the completion of alloying processes. In the chromium alloy steel, the presence of the stable chromium oxides delays these processes up to higher temperatures, while in the other steels that are based on plain iron powder, these processes take place earlier in the heating stage, at lower temperatures. Compared to the standard Fe-C and Fe-Cu-C grades, the Cr-Mo steel requires more sophisticated sintering to ensure oxygen removal, but on the other hand it offers the best properties. The masteralloy variant, finally, can be regarded as a highly attractive compromise between manufacturing requirements, alloy element content, and product properties.

Comparison of Repeated Chemical and Microwave Disinfection on Dimensional Accuracy of Gypsum Casts

OBJECTIVE: The aim of this experimental study is to compare the dimensional accuracy of gypsum casts after repeated disinfection in microwave at 900 Watts, 2450 MHz (5 minutes) and immersion in 0.5% Sodium hypochlorite (10 minutes). Disinfecting casts is recommended to prevent cross infection but may cause dimensional changes. During fabrication of prosthesis, a cast may get contaminated several times so there is a need of repeated disinfection. METHODOLOGY: Sample size was 33 (11 in each group), calculated through WHO software for sample size determination by using standard deviation of 0.16 at 95% confidence interval and 80% power of study. Impressions in irreversible hydrocolloid were recorded of an acrylic cast fabricated for this study. The impressions were poured with die stone and were randomly divided into 3 groups; Group I: Microwave disinfection, Group II: Immersion disinfection in 0.5% Sodium hypochlorite, Group III: Control group. For Groups I and II, each cast was disinfected 7 times with 5 minutes interval between two disinfection cycles, after every cycle anteroposterior and mediolateral measurements were recorded using digital Vernier caliper (accuracy upto 0.01 mm). For group III, casts were rinsed with distilled water, dried in open air within temperature range of 28+/-2OC for 10 mins followed by anteroposterior and mediolateral measurements. This procedure was repeated seven times for each cast. RESULTS: Anteroposterior and Mediolateral differences of dimensional change between and within the Group A, B and C was calculated by One Way ANOVA. Inter/intra examiner reliability was taken into consideration at the time of study. Mean dimensional change in the casts were insignificant through six disinfecting cycles. However, in the seventh cycle, a significant difference (p=0.003) was observed in the anteroposterior dimension (0.03% dimensional change for Group A and 1.26 % for Group B whereas, in mediolateral dimension, dimensional change was 0.35% for Group A and 0.59% for Group B (p=0.004). Dimensional change of >0.5% was considered as the cutoff value for casts to be considered as dimensionally accurate. Casts disinfected through immersion disinfection did not produce dimensionally inaccurate casts in anteroposterior dimension after third cycle and in seventh cycle in mediolateral dimension. However, result is significant only in seventh cycle. Microwave disinfection produced dimensionally accurate casts throughout all cycles. CONCLUSION: Microwave disinfected casts remained dimensionally stable compared to immersion disinfection. KEYWORDS: Disinfection, microwave, immersion, dimensional stability, gypsum casts

Three-dimensional Change of Elastomeric Impression Materials During the First 24 Hours: A Pilot Study

SUMMARY Objectives: To evaluate the three-dimensional (3D) changes of three elastomeric impression materials using a novel measurement method for the first 24 hours after preparation. Methods and Materials: Three impression materials consisting of a low-viscosity polyvinyl siloxane (PVS) (Aquasil LV, Dentsply Sirona, Charlotte, NC, USA) and two vinyl polyether silicone (VPES) materials consisting of a light body (EXA’lence LB, GC America, Alsip, IL, USA) and monophase (EXA’lence Monophase, GC America) materials were used in this study. All materials were prepared following manufacturer’s recommendations with approximately 1–2 millimeters of material placed on the measurement pedestal of a calibrated noncontact, video imaging based, volumetric change measuring device (AcuVol ver 2.5.9, Bisco, Schaumburg, IL, USA). Data collection was initiated immediately, with measurements made every 30 seconds for 24 hours. Each material was evaluated 10 times (n=10). Evaluated parameters included were 24-hour mean shrinkage, mean shrinkage at time of recommended first pour, mean shrinkage between recommended first pour and 24 hours, mean maximum shrinkage, and the time of maximum shrinkage. Mean data, both within and between each group, was evaluated using Kruskal–Wallis/Dunn’s tests at a 95% level of confidence (α=0.05). Results: All three materials were found to have significant differences (p<0.001) in volumetric shrinkage over 24 hours. Aquasil LV and EXA’lence LB polymerization shrinkage rates were statistically similar all through the 24-hour evaluation (p=0.92). All three materials demonstrated similar (p=0.19) shrinkage between 10 and 15 minutes after preparation, while between 5 and 16 hours both EXA’lence Monophase and low-viscosity materials demonstrated similar polymerization shrinkage values (p=0.22). EXA’lence Monophase demonstrated significantly greater 24-hour mean shrinkage (p<0.008) as well as shrinkage between recommended first pour time and 24 hours (p=0.003) than Aquasil LV and EXA’lence LB. EXA’lence Monophase demonstrated significantly greater (p=0.002) shrinkage at the recommended time of first pour as compared to Aquasil LV and EXA’lence LB that displayed similar shrinkage (p=0.89). Furthermore, all materials demonstrated increasing polymerization shrinkage values that reached a maximum between 16 for Aquasil LV and 20 hours for EXA’lence LB, after which some relaxation behavior was observed. However, EXA’lence Monophase did not display any relaxation behavior over the 24-hour evaluation. Conclusions: Under the conditions of this study, volumetric polymerization shrinkage was observed for one polyvinyl siloxane (PVS) and two vinyl polyether silicone (VPES) materials for up to 24 hours. All impression materials exhibited fast early volumetric shrinkage that continued past the manufacturer’s recommended removal time. Dimensional change behavior was not uniform within or between groups; resultant volume change between the manufacturer recommended pouring time and 24 hours might represent up to from 20% to 30% of the total material shrinkage. It may be prudent to pour elastomeric impressions at the earliest time possible following the manufacturer’s recommendations.

Dimensional stability of stored extended-pour irreversible hydrocolloids materials

The purpose of this study was to evaluate the linear dimensional stability of four extended-pour irreversible hydrocolloids (EPIHs). Material and Methods: Five samples per material (Cavex ColorChange, Cavex Orthotrace, Jeltrate Plus, and Orthoprint) were prepared following the manufacturers’ instructions. The samples were prepared using a cylindrical matrix coupled with a nylon-polyamide ring. Two parallel, 25-mm equidistant lines were made on its surface following ANSI/American Dental Association (ADA) Specification 18 for plaster reproducibility and compatibility and Specification 19 for linear dimensional change. The samples were stored in an environment with a relative humidity of 70% (± 3) and temperature of 28°C (± 2). Photo images were obtained using a digital camera to record images for 120 hours, with a standardized distance of 80cm between the lens and the specimen. Adobe Photoshop CS3 software was used for the measurement of the recorded images. The measurements refer to the equivalent distance between the two parallel lines printed on the samples. Data were analyzed using one-way analysis of variance (ANOVA) and Tukey’s test for multiple comparisons between the means of the groups. Results: There was no statistically significant difference (p > 0.05) when EPIHs were compared at the same time of evaluation. Orthoprint, Cavex Orthotrace, and Cavex Colorchange presented with least dimensional stability up to 24 hours (p > 0.05) of storage, followed by Jeltrate Plus (48 hours). Conclusions: Storage of EPIHs for more than 24 hours for Cavex ColorChange and 48 hours for others EPIHs studied produces significant dimensional changes in the impressions stored at a humidity of 70% (± 3) and temperature of 28°C (± 2). Extended storage times produce large dimensional changes.

Stereoscopic facial imaging for pain assessment using rotational offset microlens arrays based structured illumination

Conventional pain assessment methods such as patients’ self-reporting restrict the possibility of easy pain monitoring while pain serves as an important role in clinical practice. Here we report a pain assessment method via 3D face reading camera assisted by dot pattern illumination. The face reading camera module (FRCM) consists of a stereo camera and a dot projector, which allow the quantitative measurement of facial expression changes without human subjective judgement. The rotational offset microlens arrays (roMLAs) in the dot projector form a uniform dense dot pattern on a human face. The dot projection facilitates evaluating three-dimensional change of facial expression by improving 3D reconstruction results of non-textured facial surfaces. In addition, the FRCM provides consistent pain rating from 3D data, regardless of head movement. This pain assessment method can provide a new guideline for precise, real-time, and continuous pain monitoring.

Thin-film chemical expansion of ceria based solid solutions: laser vibrometry study

The chemical expansion of Pr0.1Ce0.9O2–δ (PCO) and CeO2–δ thin films is investigated in the temperature range between 600 °C and 800 °C by laser Doppler vibrometry (LDV). It enables non-contact determination of nanometer scale changes in film thickness at high temperatures. The present study is the first systematic and detailed investigation of chemical expansion of doped and undoped ceria thin films at temperatures above 650 °C. The thin films were deposited on yttria stabilized zirconia substrates (YSZ), operated as an electrochemical oxygen pump, to periodically adjust the oxygen activity in the films, leading to reversible expansion and contraction of the film. This further leads to stresses in the underlying YSZ substrates, accompanied by bending of the overall devices. Film thickness changes and sample bending are found to reach up to 10 and several hundred nanometers, respectively, at excitation frequencies from 0.1 to 10 Hz and applied voltages from 0–0.75 V for PCO and 0–1 V for ceria. At low frequencies, equilibrium conditions are approached. As a consequence maximum thin-film expansion of PCO is expected due to full reduction of the Pr ions. The lower detection limit for displacements is found to be in the subnanometer range. At 800 °C and an excitation frequency of 1 Hz, the LDV shows a remarkable resolution of 0.3 nm which allows, for example, the characterization of materials with small levels of expansion, such as undoped ceria at high oxygen partial pressure. As the correlation between film expansion and sample bending is obtained through this study, a dimensional change of a free body consisting of the same material can be calculated using the high resolution characteristics of this system. A minimum detectable dimensional change of 5 pm is estimated even under challenging high-temperature conditions at 800 °C opening up opportunities to investigate electro-chemo-mechanical phenomena heretofore impossible to investigate. The expansion data are correlated with previous results on the oxygen nonstoichiometry of PCO thin films, and a defect model for bulk ceria solid solutions is adopted to calculate the cation and anion radii changes in the constrained films during chemical expansion. The constrained films exhibit anisotropic volume expansion with displacements perpendicular to the substrate plane nearly double that of bulk samples. The PCO films used here generate high total displacements of several 100 nm’s with high reproducibility. Consequently, PCO films are identified to be a potential core component of high-temperature actuators. They benefit not only from high displacements at temperatures where most piezoelectric materials no longer operate while exhibiting, low voltage operation and low energy consumption.