Inverse modeling of turbidity currents using an artificial neural network approach: verification for field application

Although in situ measurements in modern frequently occurring turbidity currents have been performed, the flow characteristics of turbidity currents that occur only once every 100 years and deposit turbidites over a large area have not yet been elucidated. In this study, we propose a method for estimating the paleo-hydraulic conditions of turbidity currents from ancient turbidites by using machine learning. In this method, we hypothesize that turbidity currents result from suspended sediment clouds that flow down a steep slope in a submarine canyon and into a gently sloping basin plain. Using inverse modeling, we reconstruct seven model input parameters including the initial flow depth, the sediment concentration, and the basin slope. A reasonable number (3500) of repetitions of numerical simulations using a one-dimensional layer-averaged model under various input parameters generates a dataset of the characteristic features of turbidites. This artificial dataset is then used for supervised training of a deep-learning neural network (NN) to produce an inverse model capable of estimating paleo-hydraulic conditions from data on the ancient turbidites. The performance of the inverse model is tested using independently generated datasets. Consequently, the NN successfully reconstructs the flow conditions of the test datasets. In addition, the proposed inverse model is quite robust to random errors in the input data. Judging from the results of subsampling tests, inversion of turbidity currents can be conducted if an individual turbidite can be correlated over 10 km at approximately 1 km intervals. These results suggest that the proposed method can sufficiently analyze field-scale turbidity currents

乱流現象の統計的解明

関西学院大

Insulin-like growth factor 1 prevents neuronal cell death and paraplegia in the rabbit model of spinal cord ischemia

AbstractObjective: Insulin-like growth factor 1 has been shown to be cytoprotective against ischemia-reperfusion injury in various organs. However, spinal cord protection by insulin-like growth factor 1 has not been tested. We have therefore examined the effect of insulin-like growth factor 1 on neuronal cell death and motor function after spinal cord ischemia. Methods: Japanese white rabbits were subjected to spinal cord ischemia by clamping the abdominal aorta for 15 minutes. Insulin-like growth factor 1 (0.3 mg/kg) at a dose equipotent to insulin (0.3 IU/kg) in lowering blood glucose level or the control (phosphate-buffered saline solution as a vehicle) was administered intravenously 30 minutes before the aortic clamp. Results: Hind-limb motor function had recovered normally 48 hours after the operation in all the rabbits (n = 8) treated with insulin-like growth factor 1. In contrast, all the control-treated (n = 8) and all but one of the insulin-treated (n = 6) rabbits had deteriorated to paraplegia by 48 hours after the operation. Histopathologic sections in the involved spinal cord segment showed that a significantly (P <.0001) greater number of motor neuron cells were preserved in the rabbits treated with insulin-like growth factor 1 (17.9 ± 4.8 per section) than in those treated with the control (8.0 ± 2.1). Although insulin was equipotent to insulin-like growth factor 1 in preserving the number of motor neuron cells (18.5 ± 2.7), the percentage of motor neuron cells positive for terminal deoxynucleotidyltransferase–mediated deoxyuridine triphosphate-biotin nick-end labeling were significantly (P <.01) smaller in the rabbits treated with insulin-like growth factor 1 (6.0 ± 4.6) compared with those treated with the control (54.6 ± 33.8) and insulin (26.2 ± 11.7). Immunohistochemical studies revealed that insulin-like growth factor 1 increased expression of the antiapoptotic Bcl-xL protein and inhibited expression of the proapoptotic Bax protein in motor neuron cells 24 and 48 hours after the operation. In contrast, expression of only Bax was increased after the operation in other groups of rabbits subjected to spinal cord ischemia. Conclusions: These results suggest that insulin-like growth factor 1, but not insulin with a conventional dose, protects motor neuron cells from ischemic spinal cord injury associated with differential regulation of Bcl-xL and Bax protein.J Thorac Cardiovasc Surg 2001;122:136-4

Peyer’s Patches in the Terminal Ileum in Ulcerative Colitis: Magnifying Endoscopic Findings

Peyer’s patches (PPs), a major component of the gut-associated lymphoid tissue, serve as important antigen entry sites in mucosal immunity. PPs may play a role in the extension of ulcerative colitis (UC) into the terminal ileum. We sought to clarify the magnified endoscopic findings of the PPs in the terminal ileum of UC patients. Eighteen UC patients underwent magnifying chromoendoscopy before initial treatment to evaluate the follicle-associated epithelium (FAE) on the PPs domes and the surrounding villi. In 8 UC patients, as in healthy controls, the PPs’ domes were slightly elevated, covered with the regular FAE lining, and surrounded by dense and bulky villi; however, in 10 UC patients, the PPs’ domes were irregular, and the surrounding villi were sparse and atrophic. These abnormal findings within the PPs were associated with minimal mucosal lesions but not with backwash ileitis; both electron microscopy and magnifying endoscopy confirmed that these lesions were reversible following remission with prednisolone-mesalazine therapy. Similar to Crohn’s disease patients, UC patients commonly had abnormalities in the FAE on PPs’ domes and the surrounding villi on magnifying endoscopy

Retention of Capsule Endoscopy at the Site of NSAIDs-induced Intestinal Ulcer ―Lessons to Learn―

A 77-year-old man with a history of non-steroidal anti-inflammatory drugs (NSAID) use was admitted to our hospital due to anemia and hypoalbuminemia. Radioisotope scintigraphy indicated protein loss from the small intestine. The patient underwent capsule endoscopy, which was later found to be retained in the ileum. Double-balloon endoscopy showed multiple strictures with ulcers in the small intestine. The capsule was found in proximal to one of the stenosis, and was removed by doubleballoon enteroscopy. Based on endoscopic findings, NSAID-induced enteritis was diagnosed. Although anemia and hypoalbuminemia improved after discontinuing NSAID, the patient developed ileus and underwent partial resection of the ileum. Multiple diaphragm-like strictures were present in the resected intestine. The current case highlights the importance of screening for intestinal strictures when NSAID ulcer is suspected

The "Rou-Seki" marble from Nakano in Ichiu area, East Shikoku : research of marbles relating with the construction of National Diet Building of Japan in Tokyo

国会議事堂関連石材として文献資料に登場する一宇中野の「ろう石」大理石を調査し，採掘跡を確認した。「ろう石」は三波川帯南縁に露出する中野緑色岩類北縁に随伴する石灰質片岩である。その採掘跡は，文献に記述された大正末～昭和初期の当時の状況で残されていることが確認された。徳島県産大理石としては，稀少な石灰質片岩であり，近代初期の採掘跡として貴重であることから，その保存と内外への紹介が期待される