• Elastomers and Composites
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• v.40 no.1
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• pp.59-65
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• 2005

Zinc methacrylate(ZMA) was incorporated into ethylene-propylene diene rubber(EPDM) by direct mixing of the metal salt with the rubber or was in-situ prepared in the rubber matrix through neutralization reaction of zinc oxide(ZnO) and methacrylic acid(MAA). Tensile and tear tests showed that ZMA had a great reinforcing effect for the EPDM. It was also found that ZMA reinforced EPDM vulcanizates can retain their mechanical properties under thermo-oxidative aging. Moreover the incorporation of ZMA induces a substantial improvement in the adhesive strength of the EPDM onto aluminum substrate. The reinforcing effect and an enhancement in adhesion was greatly manifested when the ZMA is in-situ formed with an excess amount of ZnO. The extraordinary improvement in the properties is supposed to be related with the formation of ionic crosslink as well as the degree of dispersion or ZMA domain in the rubber matrix.

• Journal of Veterinary Clinics
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• v.24 no.2
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• pp.104-108
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• 2007

The purpose of the study is to evaluate the clinical antagonistic effect of atipamezole(0.25 mg/kg, IM) in cats anesthetized with tiletamine-zolazepam ($Zoletil^{(R)}$, 10 mg/kg, IM) and medetomidine (0.05 mg/kg, IM). Twelve healthy 1 year old Korean mixed breed cats were used for this study. They were 4 males and 8 females. These cats were randomly assigned to two groups. One was control group ($Zoletil^{(R)}$ + medetomidine, ZM), and the other was treatment group ($Zoletil^{(R)}$ + medetomidine and antagonism by atipamezole, ZMA). All cats were examined 15 minutes before, 5, 25, 65 and 105 minutes after administration of tiletamine-zolazepam and medetomidine. Atipamezole was injected intramuscularly 20 minutes after ZM administation. Recovery time, heart rate, respiratory rate, total plasma protein and blood glucose were significantly different between ZM group and ZMA group (P<0.05). However, rectal temperature was not significantly different between ZM group and ZMA group. Two groups were able to induce sternal recumbency within 2 minutes and lateral recumbency within 4 minutes after the anesthetics injection. Mean sternal position time ($mean{\pm}SD$) was $174.0{\pm}44.6\;and\;116.2{\pm}27.3$ minutes, and mean standing position time was $210.8{\pm}45.6\;and\;154.2{\pm}21.1$ minutes in ZM and ZMA group, respectively. In these two groups, adverse effects during recovery time from anesthesia were not seen. As a result, the ZMA group had a faster recovery than the ZM group. Thus it was concluded that atipamezole could exert a useful reversal effect in cats anesthetized with medetomidine-tiletamine/zolazepam combination.

• Elastomers and Composites
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• v.47 no.4
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• pp.297-309
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• 2012

Different amounts of foaming agents were employed in natural rubber(NR)/butadiene rubber(BR) blends to understand the foaming behavior in presence of nano-reinforcing agent, zinc methacrylate (ZMA). The ZMA greatly improved most of the mechanical properties of the rubber foams, however it did not show considerable effect on the cell morphology, such as cell size, density and porosity. It was also observed that the foaming agent concentration affected all the mechanical parameters. When the content of foaming agent was increased, the number of foams was increased leading to a decrease in density of the compounds. But the size and distribution of foams remained unchanged with increased foaming agent. The effect of high styrene-butadiene rubber (HSBR) was also studied. The size of cells became smaller and the cell uniformity was improved with increasing HSBR. The foam rubber compounds showed much efficient energy absorbing capability at higher strains.

• The korean journal of orthodontics
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• v.54 no.1
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• pp.59-68
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• 2024

Objective: To investigate the long-term effects of maxillary skeletal expander (MSE) treatment on functional breathing. Methods: Objective measures of breathing, the peak nasal inspiratory flow (PNIF), and peak oral inspiratory flow (POIF), and subjective measures of breathing, the visual analog scale (VAS) and nasal obstruction symptom evaluation (NOSE) survey, were used to investigate the long-term effects of MSE in functional breathing. Seventeen patients, mean age 19.4 ± 3.9 years treated at the UCLA Orthodontics Clinic were assessed on their functional breathing at 3 timepoints: pre-expansion (T0), post-expansion (T1), and post-orthodontic treatment (T2). Results: Immediately after expansion (T1), all the objective functional breathing values were significantly increased in comparison to T0 (P < 0.05). The VAS total, VAS right and VAS left were significantly lower at T1 in comparison to T0 (P < 0.05). At 26.8 ± 3.9 months after MSE expansion (T2), PNIF total, PNIF right, PNIF left, and POIF were significantly higher when compared to T0 (P < 0.05). Also, VAS total, VAS right and VAS left were significantly lower at T2 when compared to T0 (P < 0.05). Additionally, there was a positive correlation between PNIF and the magnitude of expansion at anterior nasal spine and zygomaticomaxillary point (ZMA). There was a positive correlation between total VAS and the magnitude of expansion at the ZMA. There were no significant changes for the NOSE subjective breathing measurement at all time comparisons. Conclusions: Overall, MSE treatment produces an increased objective and subjective airway improvement that continues to remain stable in the long-term post expansion.