• Journal of the Korean Mathematical Society
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• v.45 no.6
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• pp.1725-1740
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• 2008

In this paper, we introduce a fixed point index of weakly inward 1-set-contraction mappings. With the aid of the new index, we obtain some new fixed point theorems, nonzero fixed point theorems and multiple positive fixed points for this class of mappings. As an application of nonzero fixed point theorems, we discuss an eigenvalue problem.

• Honam Mathematical Journal
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• v.30 no.1
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• pp.197-203
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• 2008

We show the existence of the unique solution of the following system of the nonlinear wave equations with Dirichlet boundary conditions and periodic conditions under some conditions $U_{tt}-U_{xx}+av^+=s{\phi}_{00}+f$ in $(-{\frac{\pi}{2},{\frac{\pi}{2}}){\times}R$, ${\upsilon}_{tt}-{\upsilon}_{xx}+bu^+=t{\phi}_{00}+g$ in $(-{\frac{\pi}{2},{\frac{\pi}{2}}){\times}R$, where $u^+$ = max{u, 0}, s, t ${\in}$ R, ${\phi}_{00}$ is the eigenfunction corresponding to the positive eigenvalue ${\lambda}_{00}$ of the wave operator. We first show that the system has a positive solution or a negative solution depending on the sand t, and then prove the uniqueness theorem by the contraction mapping principle on the Banach space.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.05
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• pp.6-9
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• 1996

In this paper, we attempted to analyze the contraction patterns of elbow flexor muscle during isometric, concentric and eccentric contraction. The analysis parameters are consisted of Sequency domain parameters (mean frequency, median frequency, skewness, kurtosis) and time domain parameters (zero crossing, positive maxima, integrated EMG). As a results, the analysis parameters have specific trends for muscles, muscle contraction patterns, muscle contraction angles. Especially, at the time domain analysis, IEMG is a dominant parameter for analysis of activation patterns, and the skewness, kurtosis are useful parameters for functional recognition.

• Proceedings of the Korean Biophysical Society Conference
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• 1997.07a
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• pp.27-27
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• 1997

The effects of $a_1$-adrenoceptor stimulation on intracellular $Ca^{2+}$ ([C $a^{2+}$]$_{i}$ ) transient, contraction, and L-type $Ca^{2＋}$ current ( $I_{Ca,L}$) were studied in single cells isolated from ventricles of guinea pig hearts. Phenylephrine, $\alpha$$_1$-adrenergic agonist, (5$\times$10$^{-5}$ ~10$^{-4}$ M) produced a biphasic pattern of inotropism： transient negative response (decrease in contraction by 23.9$\pm$2.5% of control) followed by a sustained positive response (increase in contraction by 60.0$\pm$3.4%, mean $\pm$ SD, n=12).(omitted)ted)

• The Korean Journal of Physiology
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• v.23 no.2
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• pp.301-312
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• 1989

It well known that the magnitude of contraction and the shape of action potential depend upon the stimulation frequency and the duration of resting period (positive and negative staircase). Although the underlying mechanism of the staircase phenomenon is not fully understood, it has been suggested that staircase could be related to the intracllular $Ca^{2+}$ concentration. In order to elucidate the role of intracellular $Ca^{2+}$ on the contraction and action potential staircases, we examined the effects of 1 mM 4-aminopyridine (4-AP), 0.5 uM verapamil, 1 uM ryanodine, or reduction of extracellular Na concentration to 30% $(substituted\;by\;equimolar\;Li^+)$ in small atrial strips of the rabbit $(3{\times}10\;mm)$. The results obitained were as follows; 1) When the stimulation frequency was increased from 0.1 Hz to 2 Hz, positive staircase of the contraction and elevation of plateau level in action potential were found in control and the conditions of Na reduction and treatments of 4-AP, verapamil and ryanodine. 2) When stimulation frequency returned to 0.1 Hz from 1 min rest just after 2 Hz stimulation fer 1 min, the magnitudes of initial few contractions were larger than that of steady state contraction (post-rest potentiation) except, ryanodine or Na-reduction groups. 3) Negative staircase of contraction was developed in control and 4-AP group at post-rest 0.1 Hz stimulation and the plateau level of the action potential was decreased at the same time. But the reduction of contraction or the plateau level was much smaller in 4-AP group and than in control. From the above results it can be concluded that contraction and action potential staircase is dependent upon transmembrane $Ca^{2+}-current\;and\;Ca^{2+}$release from the SR.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.1
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• pp.58-68
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• 2015

Requirements to control the large decrease in serum calcium (Ca) due to parturition and to increase the feed intake soon after parturition have been well accepted in dairy cows. This study was aimed to investigate the feed intake affected by serum Ca concentration with difructose anhydride (DFA) III supplement in dairy cows soon after parturition. Fourteen transition Holstein cows were divided into DFA and control (CONT) groups within 1 to 5 parity variations in each group. Measurement schedule for an individual cow was from 14 d before parturition to 7 d following parturition. The cows in DFA group were supplied 0.2 kg/head/d of DFA III feed containing 40 g of pure DFA III while the cows in CONT group received no DFA III. Other feeding procedures were the same for all cows in both groups. At parturition (d 0), serum Ca concentration sharply declined in both groups (p<0.05). Time interval for recovery from decreased serum Ca to its normal range (>9.0 mg/dL) tended to be faster in DFA group (12 h) than in the CONT group (48 h), but the differences were not significant. Active ruminal contraction was observed in DFA group at following parturition of d 1 (p<0.05), d 3 (p<0.05), and d 5 (p<0.01). Dry matter (DM) intake did not differ between the groups. However, positive correlations were observed between serum Ca concentration and ruminal contraction (p<0.001), and between ruminal contraction and DM intake (p<0.001) during following parturition. According to multiple regression analysis ($R^2$ = 0.824, p<0.001), the DM intake was positively affected by serum Ca concentration and ruminal contraction. These results suggest that feed intake soon after parturition in dairy cows can be increased by improvement of serum Ca concentration and active ruminal contraction, but DFA III supplementation in this study did not improve the lower serum Ca concentration due to parturition.

• Korean Journal of Radiology
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• v.23 no.1
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• pp.42-51
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• 2022

Objective: This study aimed to investigate the direction of tissue contraction after microwave ablation in ex vivo bovine liver models. Materials and Methods: Ablation procedures were conducted in a total of 90 sites in ex vivo bovine liver models, including the surface (n = 60) and parenchyma (n = 30), to examine the direction of contraction of the tissue in the peripheral and central regions from the microwave antenna. Three commercially available 2.45-GHz microwave systems (Emprint, Neuwave, and Surblate) were used. For surface ablation, the lengths of two overlapped square markers were measured after 2.5- and 5-minutes ablations (n = 10 ablations for each system for each ablation time). For parenchyma ablation, seven predetermined distances between the markers were measured on the cutting plane after 5- and 10-minutes ablations (n = 5 ablations for each system for each ablation time). The contraction in the radial and longitudinal directions and the sphericity index (SI) of the ablation zones were compared between the three systems using analysis of variance. Results: In the surface ablation experiment, the mean longitudinal contraction ratio and SI from a 5-minutes ablation using the Emprint, Neuwave, and Surblate systems were 28.92% and 1.04, 20.10% and 0.53, and 24.90% and 0.45, respectively (p < 0.001). A positive correlation between longitudinal contraction and SI was noted, and a similar radial contraction was observed. In the parenchyma ablation experiment, the mean longitudinal contraction ratio and SI from a 10-minutes ablation using the three pieces of equipment were 38.60% and 1.06, 32.45% and 0.61, and 28.50% and 0.50, respectively (p < 0.001). There was a significant difference in the longitudinal contraction properties, whereas there was no significant difference in the radial contraction properties. Conclusion: The degree of longitudinal contraction showed significant differences depending on the microwave ablation equipment, which may affect the SI of the ablation zone.

• Bulletin of the Korean Mathematical Society
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• v.52 no.6
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• pp.1819-1826
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• 2015

Following an idea of Ornstein and Sucheston, Foguel proved the so-called uniform "zero-two" law: let T : $L^1$(X, $\mathcal{F}$, ${\mu}$) ${\rightarrow}$ $L^1$(X, $\mathcal{F}$, ${\mu}$) be a positive contraction. If for some $m{\in}{\mathbb{N}}{\cup}\{0\}$ one has ${\parallel}T^{m+1}-T^m{\parallel}$ < 2, then $\lim_{n{\rightarrow}{\infty}}{\parallel}T^{m+1}-T^m{\parallel}=0$. There are many papers devoted to generalizations of this law. In the present paper we provide a multi-parametric generalization of the uniform zero-two law for $L^1$-contractions.

• The Korean Journal of Pharmacology
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• v.12 no.1
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• pp.45-55
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• 1976

The effect of positive inotropic agents on the contractile properties of myocardial muscle were studied in the cat papillary muscle preparation. For the purpose, the effects of ouabain $(1{\times}10^{-6}g/ml)$, norepinephrine (0.05r/m1) and Aconiti tuber butanol fraction (AF(5), $1{\times}10^{-4}$, $5{\times}10^{-4}$, $1{\times}10^{-3}$, $2{\times}10^{-3}g/ml$) on the contractile dynamics of the papillary muscle preparation isolated from right ventricle of cat were observed in terms of the characteristics of isometric twitch and the lengh-tension relation, the force-velocity relation and the load-extension relation of the series elastic component of contractile model of A.V. Hill. All the studied inotropic drugs similary increased the rate and the intensity of the developed isometric tension, while shortened the time from onset of contraction to peak tension and the total duration of contraction. In the afterloaded simultaneous isotonic and isometric contraction, they also similary increased the maximal velocity of shortening accompanied with the increasing the maximum developed force. In the load-extension relation all the drugs, however, had no appreciable influence on the properties of the series elastic component. Increasing the concentration, Aconiti tuber butanol fraction produced more pronounced effect on all the studied parameters of isometric and isotonic contraction of cat papillary muscle preparation. From the aspect of contractile dynamics, it seemed that the positive inotropic effect of ouabain, norepinephrine and Aconiti tuber butanol fraction are similary achieved through an influence on the behavior of the contractile component only.

• Physical Therapy Rehabilitation Science
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• v.4 no.1
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• pp.11-16
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• 2015

Objective: Prone bridge exercise is one of the core strengthening exercise for improving abdominal, lower and upper extremity muscles. In addition, coactivation of the trunk muscles and extremities is important for treatment of low back pain. This study aimed to investigate the correlation between the thickness, cross-sectional area of the target muscle, and endurance during prone bridge exercise. Our hypothesis was that an increase in muscle thickness is positively related to the hold time for the static prone bridge exercise. Design: Cross-sectional study. Methods: Fourteen healthy university students (8 men and 6 women) voluntarily participated in the study at Sahmyook University. Hold time for the prone bridge with one and both legs was measured. The resting and contracted thickness of the lateral abdominal, rectus femoris, and triceps muscles was measured using rehabilitative ultrasound imaging. The correlation between muscle thickness and endurance for maintenance time was evaluated. Results: The prone bridge with both legs and the contraction thickness of the triceps muscle showed a positive correlation (r=0.692, p<0.05); the prone bridge with one leg and the contraction thickness of the internal oblique and transversus abdominis muscles showed a positive correlation (r=0.545, 0.574, p<0.05, 0.05, respectively). Conclusions: Endurance for the prone bridge exercise with a stable support surface is correlated with the contraction thickness of arm muscles; the prone bridge exercise with an unstable support surface is correlated with the contraction thickness of the deep abdominal muscles.