• BMB Reports
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• v.34 no.6
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• pp.573-577
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• 2001

The mammalian heart is known to undergo significant mechanical changes during fetal and neonatal development. The objective of this study was to define the ontogeny of the ryanodine receptor/$Ca^{2+}$ release channel and SERCA that play the major roles in excitation-contraction coupling. Whole ventricular homogenates of fetal (F) (19 and 22 days in gestation), postnatal (N) (1 and 7 days postnatal), and adult (A) (5 weeks postnatal) Sprague-Dawley rat hearts were used to study [$^3H$]ryanodine binding and oxalate-supported $^{45}Ca^{2+}$ uptake. For the ryanodine receptor, the major findings were: (1) The ryanodine receptor density, as determined by maximal [$^3H$]ryanodine binding ($B_{max}$), increased 3 fold between the F22 and A periods ($0.26{\pm}0.1$ vs. $0.73{\pm}0.07$ pmoles/mg protein, p<0.01), whereas there was no significant change during the F22 and N1 development phases ($0.26{\pm}0.1$ vs. $0.34{\pm}0.01$). (2) Affinity of the ryanodine receptor to ryanodine did not significantly change, as suggested by the lack of change in the $K_d$ during the development and maturation. For SERCA, changes started early with an increased rate of $Ca^{2+}$ uptake in the fetal periods (F19: $8.1{\pm}1.1$ vs. F22: $19.3{\pm}2.2$ nmoles/g protein/min; p<0.05) and peaked by 7 days (N7) of the postnatal age ($34.9{\pm}2.1$). Thus, we conclude that the quantitative changes occur in the ryanodine receptor during myocardial development. Also, the maturation of the $Ca^{2+}$ uptake appears to start earlier than that of the $Ca^{2+}$ release.

• Journal of applied mathematics & informatics
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• v.28 no.3_4
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• pp.753-762
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• 2010

Let K be a nonempty closed convex subset of a real Hilbert space H. Let T : K $\rightarrow$ K be a nonexpansive mapping with a nonempty fixed point set Fix(T). Let f : K $\rightarrow$ K be a contraction mapping. Let {$\alpha_n$} and {$\beta_n$} be sequences in (0, 1) such that $\lim_{x{\rightarrow}0}{\alpha}_n=0$, (0.1) $\sum_{n=0}^{\infty}\;{\alpha}_n=+{\infty}$, (0.2) 0 < a ${\leq}\;{\beta}_n\;{\leq}$ b < 1 for all $n\;{\geq}\;0$. (0.3) Then it is proved that the modified Krasnoselski-Mann iterative sequence {$x_n$} given by {$x_0\;{\in}\;K$, $y_n\;=\;{\alpha}_{n}f(x_n)+(1-\alpha_n)x_n$, $n\;{\geq}\;0$, $x_{n+1}=(1-{\beta}_n)y_n+{\beta}_nTy_n$, $n\;{\geq}\;0$, (0.4) converges strongly to a point p $\in$ Fix(T} which satisfies the variational inequality

$\leq$ 0, z $\in$ Fix(T). (0.5) This result improves and extends the corresponding results of Yao et al[Y.Yao, H. Zhou, Y. C. Liou, Strong convergence of a modified Krasnoselski-Mann iterative algorithm for non-expansive mappings, J Appl Math Com-put (2009)29:383-389.

• Honam Mathematical Journal
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• v.6 no.1
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• pp.1-12
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• 1984

Let(X, $\Im$) be a probabilistic metric space with a t-norm. Common fixed point theorems and convergence theorems generalizing the results of Ćirić, Fisher, Sehgal, Istrătescu-Săcuiu and others are proved for three mappings P,S,T on X satisfying $F_{Pu, Pv}(qx){\geq}min\left{F_{Su,Tv}(x),F_{Pu,Su}(x),F_{Pv,Tv}(x),F_{Pu,Tv}(2x),F_{Pv,Su}(2x)\right}$ for every $u, v {\in}X$, all x>0 and some $q{\in}(0, 1)$. One of the main results is extended to uniform spaces. Mathematics Subject Classification (1980): 54H25.

• Natural Product Sciences
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• v.4 no.2
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• pp.84-87
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• 1998

Cassia fistula commonly known as Sundali was selected to evaluate its wound healing potentials based on traditional use and literature references. Methanol extract of C. fistula leaves were examined for its wound healing property in the form of an ointment in two types of wound models in rats: i) Excision wound model and ii) Incision wound model. The ointment of the leaf extract of two different concentrations (5% and 10% w/w ointment of leaves extract in simple ointment base) responded significantly in both models of wounds tested. The results were also comparable to that of standard drug, nitrofurazone in terms of wound contraction ability, epithelisation period, tensile strength and regeneration of tissue at wound area.

• Annals of Clinical Neurophysiology
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• v.1 no.2
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• pp.106-111
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• 1999

Backgroud : The generators of N37 and P37 of posterior tibial nerve somatosensory evoked potential(PTSEP) have not been exactly known. Recently, some reports suggested that P37 and N37 might have different generator. We conducted a study to know the generators of P37 and N37 of PTSEP using gating mechanism. Methods : We evaluated subcortical and cortical somatosensoy evoked potentials(SEPs) in response to posterior tibial nerve stimulation in 3 experimental conditions of foot movement and compared them with PTSEPs in full relaxation of foot. The experimental conditions were: (a) active flexion-extention of stimulated foot, (b) isometric contraction of the stimulated foot, (c) passive flexion-extention of the stimulate foot. We analyzed the latencies and amplitudes of following potentials; P30, N37, P37, and N50. Results : The amplitude of P30 potential did not change during at any paradigms. The amplitudes of P37 and N50 were significantly attenuated in all condition. However, the amplitude of N37 showed no significant change during at any paradigms. Conclusions : These results suggest that the generators of P37 and N37 of PTSEP be different in cortex.

• Journal of Conservation Science
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• v.20
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• pp.81-88
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• 2007

For the conservation of wooden coffin from King Muryeong's Tomb we examined weight change, shrinkage rate, color changes, and permeation expansion according to the permeation pretreatment chemicals by producing experimental samples with similar physical properties. The result shows Dammar 2 %(in xylene) as the most excellent treatment for protecting deformation by contraction and strengthening materials which are also maintaining its original colors of wood. Therefore, we could get strengthening conservation treatments of dried wooden coffin materials by using Dammar.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.3
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• pp.315-321
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• 2001

Aerodynamic lenses are widely used in generating particle beams of high density and small diameter, but analytical or modeling studies are limited only in the free molecular regime. In this study, it is shown that generating particle beam is also possible in atmospheric pressure range, and the mechanism of generating particle beam using an orifice is analysed into three different parts : fluid dynamic contraction, diffusional defocusing, and inertial focusing. In laminar flow conditions, the diffusional defocusing effect can be neglected, and the effects of inertial focusing can be expressed in terms of the orifice size and Stokes number. Numerical experiments are done for two different orifices, d/D=1/5 and 1/10 and particle diameter d(sub)p=1-10 ㎛. The results for two different orifices can be made into a single curve when a modified Stokes number is used. The inertial focusing effect diminishes when the modified Stokes number becomes smaller than 10(sup)-2.

• Journal of the Korean Society of Physical Medicine
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• v.16 no.3
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• pp.107-113
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• 2021

PURPOSE: Selective strengthening of the transverse abdominis muscle (TrA) during abdominal hollowing makes an important contribution to the stability and control of the spine. This study examined the effects of abdominal hollowing exercise (AHE) according to the visual feedback method on the external oblique, internal oblique, and transverse abdominis muscles. METHODS: Twenty healthy subjects were assigned randomly to an AHE with visual feedback from real-time ultrasound image (group A, n = 10), AHE with visual feedback with pressure biofeedback unit (group B, n = 10). Both groups underwent 20 min of AHE with visual feedback once daily, five days/week for two weeks. The changes in the muscle thickness of the TrA, internal oblique abdominal muscle (IO), and external oblique abdominal muscle (EO) were measured by ultrasonography. RESULTS: The thickness of TrA was changed significantly in both groups (p < .05). However, the lowest minimal detectable changes were achieved in Group A. The thickness of the IO and EO muscles in group A was changed significantly, but there were no significant changes in group B. CONCLUSION: Both visual feedback methods were effective for strengthening the TrA muscles selectively. Nevertheless, AHE with visual feedback using real-time ultrasound images may be more useful in trA muscle contraction.

• The Korean Journal of Physiology
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• v.28 no.1
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• pp.27-35
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• 1994

We investigated the alterations in basal tone of aortic strips by changing the Ca concentration, basal $^{45}Ca$ uptake and $^3H-nitrendipine$ binding of the single cells of aortic smooth muscles in the spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats. While the basal tone of the aortic strips in WKY rats was not affected by alteration of Ca concentration, that in SHR was decreased by the removal of Ca from the bath solution and was recovered by the restoration of Ca to normal levels. This contraction increased in a Ca concentration-dependent manner and reached a maximum at 2 mM Ca. The basal tone of aorta in SHR was suppressed by verapamil $(10^{-6}M)$. The basal tone of aorta in SHR increased about 50% in the strips of endothelial rubbing, compared with that of intact endothelium. Basal $^{45}Ca$ uptake in the aortic single smooth muscle cells of SHR was greater than that of WKY (p<0.01), Specific bindings of $[^3H]nitrendipine$ in the aortic single smooth muscles of SHR and WKY were saturable. The dissociation constant $(K_d)\;was\;0.71{\pm}0.15\;and\;1.18{\pm}0.08nM$ SHR, respectively, and the difference in $K_d$ between two strains was statistically significant (p<0.03). The maximal binding capacity $(B_{max})\;was\;34.6{\pm}3.2\;and\;47.4{\pm}4.3\;fmol/10^6$ SHR respectively, and the difference of $(B_{max})$ between two strains was statistically significant (p<0.05). from the above results, it is suggested that the increase of Ca influx via potential-operated Ca channels and the increase of the number of dihydropyridine-sensitive Ca channels contribute to high basal tone of the aortic strips in SHR.

• Journal of Chest Surgery
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• v.51 no.4
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• pp.266-272
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• 2018

Background: Limited comparative data are available on the efficacy of cryoablation versus radiofrequency ablation in patients with atrial fibrillation. This study aimed to compare radiofrequency ablation and cryoablation with regard to clinical outcomes and the restoration of sinus rhythm or atrial contractility. Methods: A total of 239 patients who underwent surgical ablation between August 2003 and December 2016 at our institution were included. The patients were divided into 2 groups according to the energy device that was used (group A: n=140, radiofrequency ablator; group B: n=99, cryoablator). Echocardiographic data, overall survival, and major cardiovascular and cerebrovascular event (MACCE)-free survival were compared between the 2 groups. Results: At 1 year of follow-up, the atrial contractility recovery rate was 32.2% (19 of 59) in group A and 48.8% (21 of 44) in group B. In addition, cryoablation was found to be a predictive factor for the recovery of atrial contractility (cryoablation vs. radiofrequency ablation: odds ratio, 2.540; 95% confidence interval, 1.063-6.071; p=0.036). The left ventricular ejection fraction was significantly higher in group B ($53.1%{\pm}11.5%$ vs. $59.1%{\pm}6.3%$, p=0.001). The median follow-up duration was 36 months. The 5-year overall survival rate was $80.1%{\pm}3.6%$ in group A and $92.1%{\pm}2.9%$ in group B (p=0.400). The 5-year MACCE-free survival rate was $70.3%{\pm}4.0%$ in group A and $70.9%{\pm}5.6%$ in group B (p=0.818). Conclusion: Cryoablation was associated with a higher atrial contractility restoration rate and better left ventricular function than radiofrequency ablation. However, no significant relationship was observed between the energy source and overall or MACCE-free survival.