Effect of Masticatory Movement Using Gum on Walking and Cycling: A Randomized Crossover Design

PURPOSE: Gum chewing stimulates the sympathetic nervous system and increases energy consumption. However, the effect of mastication on physical activity remains unclear. This study aimed to investigate the effect of gum masticatory movement on physiological markers related to walking and muscle activation during cycling in different patient groups.METHODS: Using a randomized crossover design, 25 participants participated in walking trials with a 1-week washout; the trials included chewing gum (GUM), taking a candy with the same ingredients as the gum (CAN), and no ingestion (CON). Energy expenditure (EE), metabolic equivalent (MET), oxygen consumption (VO2), and heart rate were measured using a portable metabolic device. The walking distance was also calculated. In the cycling experiment, the other 19 participants randomly completed 7 minutes of the three trials (GUM, CAN, CON) with a 15-minute break. The mean cycling period (MCP), cycle number (CN), coefficient of variation of the cycling period (CV), and integrated electromyography (iEMG) results were measured using the Delsys Trigno™ Wireless EMG System.RESULTS: The walking distance was significantly higher in the GUM group than in the CAN and CON groups by an average of 78 m (7.4%, p<.05). Comparing the GUM and CON groups, EE, METs, and VO2 demonstrated a partially significant increase after 15 minutes. In the cycling experiment, there were no significant differences in the effects of the trials on cycling performance (MCP, CN, CV). However, significant differences were observed in the GUM group for the iEMG results.CONCLUSIONS: Our study results suggest that gum chewing improves physical performance, such as walking distance, and improves energy metabolism, such as EE and METs. Additionally, it can influence the improvement in the lower limb muscle activity during cycling.

Study on the Relationship between BO–LID and LeTID in Czochralski-Grown Monocrystalline Silicon

Most research about Light and elevated Temperature Induced Degradation (LeTID) is focused on multicrystalline silicon (mc-Si). In this work, the degradation kinetics of Czochralski-grown monocrystalline silicon (Cz-Si) induced by light at an elevated temperature were studied in detail. The lifetime evolutions over time during (1) light soaking (LS), (2) dark annealing–light soaking (DA–LS), and (3) DA–LS cycling experiments were analyzed. Ratios of the capture coefficients for the electrons and holes (k-values) were used to characterize the possible defects responsible for degradation. We found that the behavior of degradation and recovery under light soaking with or without a dark annealing treatment was mostly like boron–oxygen (BO)-related degradation but gave k-values from 19 to 25. In the DA–LS cycling experiment, the max degradation amplitudes hardly changed from the second cycle, and the k-values decreased with an increase in the cycling number. We then analyzed the possible reactions in Cz-Si and discuss the relationship between BO defects and LeTID.

Large-Scale Bicycle Flow Experiment: Setup and Implementation

Cycling research at the operational behavioral level is limited, mainly because of the lack of empirical data. To overcome this data shortage, we performed a controlled, large-scale cycling experiment in the Netherlands. In this paper we describe the methodology for setting up and implementing such an experiment, from the motivation of its design using a conceptual model describing cyclist behavior to adjustments that were required during the experiment. The main contribution of this paper is, therefore, to be used as a guide in future experimental data collections. Moreover, we present the characteristics of the participants and their bicycles, and provide a qualitative description of phenomena observed during the experiment. Finally, we elaborate on the potential that the collected dataset holds for future research into understanding and modeling operational cycling behavior.

Experimental Study on Damage Deterioration and Tensile Characteristics of Rock under Freeze-Thaw Environment

The basic mechanical problem facing of environmental geotechnical engineering in cold regions is the physical and mechanical properties of rocks under freeze-thaw conditions. The freeze-thaw cycling experiment was conducted first for two types of rock which are red sandstone and shale, then the splitting tensile experiment on different freeze-thaw cycles. The damage deterioration and breaking behavior under freeze-thaw conditions was investigated, and the influence of lithology and freeze-thaw cycle on anti-tensile characteristics of rock was studied. It is shown that three freeze-thaw damage deterioration modes of two kinds of rock are spalling mode, fracture mode and crack mode. The freeze-thaw cycle leads to irreversible deterioration on physical and mechanical properties for rock, but the damage of red sandstone is more serious than that of shale by the number of freeze-thaw cycles. The regularity of freeze-thaw effects of compression and tensile characteristics for two rocks are identical, but the tensile characteristic is more sensitive to freeze-thaw cycle.

Mechanically clamped PZT ceramics investigated by First-Order Reversal Curves diagram

The First Order Reversal Curves (FORC) diagrams method was developed for characterizing the switching properties of ferroelectrics. In the present paper, the FORC method was applied for hard Pb(Zr,Ti)O3 ceramics with symmetric and asymmetric clamping. An ideal high-oriented single-crystalline ferroelectric with rectangular P(E) loop would be characterised by a delta-function FORC distribution, while real ferroelectrics and mostly the polycrystalline ceramics show dispersed FORC distributions. All the investigated ceramics show FORC distributions with non-Gaussian shape, slightly elongated along the coercitive axis, meaning a high dispersion of the energy barriers separating the two bi-stable polarizations ?P. The degree of dispersion is enhanced by clamping. The maximum FORC coercivity is located at ~ (1.9-2) MV/m for all the hard ceramics. The FORC cycling experiment causes the reversal of the initial poling and result in a positive/negative bias on the FORC diagrams. According to the observed features, it results that FORC coercivity is more related to the nature of the material, while the bias field is more sensitive to the electrical and mechanical boundary conditions in which the ferroelectric ceramics evolves while switching.

Discussion on the Reliability Issues of Solder-Bump and Direct-Solder Bonded Power Device Packages Having Double-Sided Cooling Capability

Power device packages with solder-bump (SB) and direct-solder (DS) interconnections were fabricated and some of their thermomechanical reliability issues were discussed based on both thermal cycling experiment and finite element analysis (FEA). The SB interconnection shows superior reliability over the DS interconnection in the thermal cycling experiment because the mismatched coefficient of thermal expansion leads to smaller stresses at the SB interconnection under the same temperature changes. On the other hand, FEA results show that the DS package has significantly lower operating temperatures under the same double-sided cooling condition. After considering the operating temperature difference, the DS package was shown to be superior over the SB package in the power cycling analysis.

Interactions Between Strains of 2,4-Diacetylphloroglucinol-Producing Pseudomonas fluorescens in the Rhizosphere of Wheat

Strains of fluorescent Pseudomonas spp. that produce the antibiotic 2,4-diacetylphoroglucinol (2,4-DAPG) are among the most effective rhizobacteria controlling diseases caused by soilborne pathogens. The genotypic diversity that exists among 2,4-DAPG producers can be exploited to improve rhizosphere competence and biocontrol activity. Knowing that D-genotype 2,4-DAPG-producing strains are enriched in some take-all decline soils and that P. fluorescens Q8r1-96, a representative D-genotype strain, as defined by whole-cell repetitive sequence-based polymerase chain reaction (rep-PCR) with the BOXA1R primer, is a superior colonizer of wheat roots, we analyzed whether the exceptional rhizosphere competence of strain Q8r1-96 on wheat is characteristic of other D-genotype isolates. The rhizosphere population densities of four D-genotype strains and a K-genotype strain introduced individually into the soil were significantly greater than the densities of four strains belonging to other genotypes (A, B, and L) and remained above log 6.8 CFU/g of root over a 30-week cycling experiment in which wheat was grown for 10 successive cycles of 3 weeks each. We also explored the competitive interactions between strains of different genotypes inhabiting the same soil or rhizosphere when coinoculated into the soil. Strain Q8r1-96 became dominant in the rhizosphere and in nonrhizosphere soil during a 15-week cycling experiment when mixed in a 1:1 ratio with either strain Pf-5 (A genotype), Q2-87 (B genotype), or 1M1-96 (L genotype). Furthermore, the use of the de Wit replacement series demonstrated a competitive disadvantage for strain Q2-87 or strong antagonism by strain Q8r1-96 against Q2-87 in the wheat rhizosphere. Amplified rDNA restriction analysis and sequence analysis of 16S rDNA showed that species of Arthrobacter, Chryseobacterium, Flavobacterium, Massilia, Microbacterium, and Ralstonia also were enriched in culturable populations from the rhizosphere of wheat at the end of a 30-week cycling experiment in the presence of 2,4-DAPG producers. Identifying the interactions among 2,4-DAPG producers and with other indigenous bacteria in the wheat rhizosphere will help to elucidate the variability in biocontrol efficacy of introduced 2,4-DAPG producers and fluctuations in the robustness of take-all suppressive soils.