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On the Existence of Oscillatory Behavior in Gene Regulatory Networks with Cyclic Interconnections
Yutaka Hori,Akifumi Takabe,Shinji Hara 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8
In this paper, we derive an existence condition of periodic oscillationsin cyclic gene regulatory networks, of which the dynamical behavior is described by nonlinear differential equations. For this purpose, we first point out that change of the equilibrium point with respect to biochemical parameters is important for comprehensive analysis, and show the properties which the equilibrium point should satisfy. Then, by employing the seproperties, we derive an analytic condition for the existence of periodic oscillationsincy clicgene regulatory networks where genes have homogeneous dynamics Compared to preceding studies, our condition has the following distinctive features: (i) it is analytically written only interms of the system parameters,(ii) it is applicable for cyclicgene regulatory networks consisting of any number of genes. Thus, biological inter pretation of the result is easily obtained, and, infact, it is concluded that cyclic generegulatory networks with homogeneous genedynamics tend to have periodicos cillations as the number of genes gets large. Finally, we discuss the case of cyclicgene regulatory networks with heterogeneous genedynamics.
Sofue Keitaro,Shimada Ryuji,Ueshima Eisuke,Komatsu Shohei,Yamaguchi Takeru,Yabe Shinji,Ueno Yoshiko,Hori Masatoshi,Murakami Takamichi 대한영상의학회 2024 Korean Journal of Radiology Vol.25 No.1
Despite improvements in operative techniques and perioperative care, post-hepatectomy liver failure (PHLF) remains the most serious cause of morbidity and mortality after surgery, and several risk factors have been identified to predict PHLF. Although volumetric assessment using imaging contributes to surgical simulation by estimating the function of future liver remnants in predicting PHLF, liver function is assumed to be homogeneous throughout the liver. The combination of volumetric and functional analyses may be more useful for an accurate evaluation of liver function and prediction of PHLF than only volumetric analysis. Gadoxetic acid is a hepatocyte-specific magnetic resonance (MR) contrast agent that is taken up by hepatocytes via the OATP1 transporter after intravenous administration. Gadoxetic acid-enhanced MR imaging (MRI) offers information regarding both global and regional functions, leading to a more precise evaluation even in cases with heterogeneous liver function. Various indices, including signal intensity-based methods and MR relaxometry, have been proposed for the estimation of liver function and prediction of PHLF using gadoxetic acid-enhanced MRI. Recent developments in MR techniques, including high-resolution hepatobiliary phase images using deep learning image reconstruction and whole-liver T1 map acquisition, have enabled a more detailed and accurate estimation of liver function in gadoxetic acid-enhanced MRI.
Yuji Matsuoka,Kenji Endo,Hidekazu Suzuki,Yasunobu Sawaji,Hirosuke Nishimura,Taichiro Takamatsu,Osamu Kojima,Kazuma Murata,Takeshi Seki,Shinji Horie,Takamitsu Konishi,Kengo Yamamoto 대한척추외과학회 2018 Asian Spine Journal Vol.12 No.4
Study Design: Retrospective study. Purpose: To investigate the relationship between preoperative total spinal sagittal alignment and the early onset of adjacent segment degeneration (ASD) after single-level posterior lumbar interbody fusion (PLIF) in patients with normal sagittal spinal alignment. Overview of Literature: Postoperative early-onset ASD is one of the complications after L4–L5 PLIF, a common surgical procedure for lumbar degenerative disease in patents without severe sagittal imbalance. A better understanding of the preoperative characteristics of total spinal sagittal alignment associated with early-onset ASD could help prevent the condition. Methods: The study included 70 consecutive patients diagnosed with lumbar degenerative disease who underwent single-level L4–L5 PLIF between 2011 and 2015. They were divided into two groups based on the radiographic progression of L3–L4 degeneration after 1-year follow-up: the ASD and the non-ASD (NASD) group. The following radiographic parameters were preoperatively and postoperatively measured: sagittal vertebral axis (SVA), thoracic kyphosis (TK), lumbar lordosis, pelvic tilt, and pelvic incidence (PI). Results: Eight of the 70 patients (11%) experienced ASD after PLIF (three males and five females; age, 64.4±7.7 years). The NASD group comprised 20 males and 42 females (age, 67.7±9.3 years). Six patients of the ASD group showed decreased L3–L4 disc height, one had L3–L4 local kyphosis, and one showed both changes. Preoperative SVA, PI, and TK were significantly smaller in the ASD group than in the NASD group (p<0.05). Conclusions: A preoperative small SVA and TK with small PI were the characteristic alignments for the risk of early-onset ASD in patients without preoperative severe sagittal spinal imbalance undergoing L4–L5 single-level PLIF.