• Animal cells and systems
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• v.15 no.4
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• pp.279-286
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• 2011

Hypoxic ischemia injury is a common cause of functional brain damage, resulting from a decrease in cerebral blood flow and oxygen supply to the brain. The main problems associated with hypoxic ischemia to the brain are memory impairment and dopamine dysfunction. Hypothermia has been suggested to ameliorate the neurological impairment induced by various brain insults. In this study, we investigated the effects of hypothermia on memory function and dopamine synthesis following hypoxic ischemia to the brain in rats. For this purpose, a step-down avoidance task, a radial eight-arm maze task, and immunohistochemistry for tyrosine hydroxylase (TH) and 5-bromo-2'-deoxyuridine (BrdU) were performed. The present results indicated that the hypoxic ischemia-induced disturbance of the animal's performances and spatial working memory was associated with a decrement in TH expression in the substantia nigra and striatum, and an increase in cell proliferation in the hippocampal dentate gyrus. Hypothermia treatment improved the animals' performance and spatial working memory by suppressing the decrement in TH expression in the substantia nigra and striatum and the increase in cell proliferation in the dentate gyrus. We suggest that hypothermia can be an efficient therapeutic modality to facilitate recovery following hypoxic ischemia injury to the brain, presumably by modulating the dopaminergic cell loss.

• Proceedings of the Optical Society of Korea Conference
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• 1998.08a
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• pp.94-96
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• 1998

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.4
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• pp.945-951
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• 2008

In this paper, a new high performance data cache scheme that improves exploitation of both the spatial and temporal locality is proposed. The proposed data cache consists of a hardware prefetch unit and two sub-caches such as a direct-mapped (DM) cache with a large block size and a fully associative buffer with a small block size. Spatial locality is exploited by fetching and storing large blocks into a direct mapped cache, and is enhanced by prefetching a neighboring block when a DM cache hit occurs. Temporal locality is exploited by storing small blocks from the DM cache in the fully associative buffer according to their activity in the DM cache when they are replaced. Experimental results on Spec2000 programs show that the proposed scheme can reduce the average miss ratio by $12.53%\sim23.62%$ and the AMAT by $14.67%\sim18.60%$ compared to the previous schemes such as direct mapped cache, 4-way set associative cache and SMI(selective mode intelligent) cache[8].

• Journal of Korea Spatial Information System Society
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• v.7 no.1 s.13
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• pp.25-37
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• 2005

Recently, with the development of wireless communications and mobile computing, interest about mobile computing is rising. Mobile computing can be regarded as an environment where a user carries mobile devices, such as a PDA or a notebook, and shares resources with a server computer via wireless communications. A mobile database refers to a database which is used in these mobile devices. The mobile database can be used in the fields of insurance business, banking business, medical treatment, and so on. Especially, LBS(Location Based Service) which utilizes location information of users becomes an essential field of mobile computing. In order to support LBS in the mobile environment, there must be an Embedded Spatial MMDBMS(Main-Memory Database Management System) that can efficiently manage large spatial data in spatial mobile devices. Therefore, in this paper, we designed and implemented the Embedded Spatial MMDBMS, extended from the HSQLDB which is an existing MMDBMS for PC, to manage spatial data efficiently in spatial mobile devices. The Embedded Spatial MMDBMS adopted the spatial data model proposed by ISO(International Organization for Standardization), provided the arithmetic coding method that is suitable for spatial data, and supported the efficient spatial index which uses the MBR compression and hashing method suitable for spatial mobile devices. In addition, the system offered the spatial data display capability in low-performance processors of spatial mobile devices and supported the data caching and synchronization capability for performance improvement of spatial data import/export between the Embedded Spatial MMDBMS and the GIS server.

• Korean Journal of Child Studies
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• v.7 no.1
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• pp.85-95
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• 1986

The purpose of the present research was to study effects of experimental conditions and developmental tendency in the use of external cues in memory-for-object location in toddlers. This study consisted of two experiments. In study 1, the subjects were 12 toddlers, 18 to 23 months old ; in study 2, 30 toddlers, 24 to 41 months old. The findings showed that memory-for-object location in toddlers was different in accordance with experimental conditions; that is, memory-for-object location in the natural condition was significantly better than in the artificial condition. Effects of external cues were found ; that is, memory-for-object location was best in the condition of spatial cues, and next best in the condition of picture cues, and least good in the no cue condition.

• Sleep Medicine and Psychophysiology
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• v.7 no.1
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• pp.10-17
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• 2000

To investigate the neurobiological bases of learning and memory is one of the ambitious goals of modern neuroscience. The progress in this field of recent years has not only brought us closer to understanding the molecular mechanism underlying long-lasting changes in synaptic strength, but it has also provided further evidence that these mechanisms are required for memory formation. Since twenty years ago, several studies for the tests of the hypothesis that NMDA-dependent hippocampal long-term potentiation(LTP) underlies learning have been reported. Also, in the recent year, data from mutant mice showed that a potential role for NMDA-dependent LTP in hippocampal CA1 and spatial learning. Although the current evidence for the role of NMDA receptor in learning and memory is not still obvious, NMDA receptor seems to act as a critical switch for activation of a cascade of events that underlie synaptic plasticity.

• Journal of the Semiconductor & Display Technology
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• v.22 no.2
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• pp.6-10
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• 2023

High-potential data can be predicted and stored in the cache to prevent cache misses, thus reducing the processor's request and wait times. As a result, the processor can work non-stop, hiding memory latency. By utilizing the temporal/spatial locality of memory access, the prefetcher introduced to improve the performance of these computers predicts the following memory address will be accessed. We propose a prefetcher that applies the GRU model, which is advantageous for handling time series data. Display the currently accessed address in binary and use it as training data to train the Gated Recurrent Unit model based on the difference (delta) between consecutive memory accesses. Finally, using a GRU model with learned memory access patterns, the proposed data prefetcher predicts the memory address to be accessed next. We have compared the model with the multi-layer perceptron, but our prefetcher showed better results than the Multi-Layer Perceptron.

• Korean Journal of Pharmacognosy
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• v.45 no.1
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• pp.48-54
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• 2014

Alzheimer's disease is progressive neurodegenerative disorder by the loss of memory and learning abilities. Codonopsis lanceolata (C. lanceolata) is traditional medicinal plant used for the treatment of inflammatory diseases. The aim of study was to evaluate the effect of steamed C. lanceolata on scopolamine-induced memory impairment in the Morris water maze test and passive avoidance test. In addition, this study investigated the neuroprotective effects of steamed C. lanceolata on glutamate-induced cell death in HT22 cells using MTT assay. The results showed that steamed C. lanceolata (500 mg/kg body weight, p.o.) reversed spatial memory impairment by scopolamine in Morris water maze test and passive avoidance test. Steamed C. lanceolata attenuated memory impairment by scopolamine compared with common C. lanceolata. In addition, administration of steamed C. lanceolata significantly also reduced cell death. We suggest that steaming process more improve cognitive enhancing and neuroprotective effect of C. lanceolata than common C. lanceolata.

• Toxicological Research
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• v.31 no.4
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• pp.347-354
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• 2015

Excess manganese (Mn) is neurotoxic. Increased manganese stores in the brain are associated with a number of behavioral problems, including motor dysfunction, memory loss and psychiatric disorders. We previously showed that the transport and neurotoxicity of manganese after intranasal instillation of the metal are altered in Hfe-deficient mice, a mouse model of the iron overload disorder hereditary hemochromatosis (HH). However, it is not fully understood whether loss of Hfe function modifies Mn neurotoxicity after ingestion. To investigate the role of Hfe in oral Mn toxicity, we exposed Hfe-knockout ($Hfe^{-/-}$) and their control wild-type ($Hfe^{+/+}$) mice to $MnCl_2$ in drinking water (5 mg/mL) for 5 weeks. Motor coordination and spatial memory capacity were determined by the rotarod test and the Barnes maze test, respectively. Brain and liver metal levels were analyzed by inductively coupled plasma mass spectrometry. Compared with the water-drinking group, mice drinking Mn significantly increased Mn concentrations in the liver and brain of both genotypes. Mn exposure decreased iron levels in the liver, but not in the brain. Neither Mn nor Hfe deficiency altered tissue concentrations of copper or zinc. The rotarod test showed that Mn exposure decreased motor skills in $Hfe^{+/+}$ mice, but not in $Hfe^{-/-}$ mice (p = 0.023). In the Barns maze test, latency to find the target hole was not altered in Mn-exposed $Hfe^{+/+}$ compared with water-drinking $Hfe^{+/+}$ mice. However, Mn-exposed $Hfe^{-/-}$ mice spent more time to find the target hole than Mn-drinking $Hfe^{+/+}$ mice (p = 0.028). These data indicate that loss of Hfe function impairs spatial memory upon Mn exposure in drinking water. Our results suggest that individuals with hemochromatosis could be more vulnerable to memory deficits induced by Mn ingestion from our environment. The pathophysiological role of HFE in manganese neurotoxicity should be carefully examined in patients with HFE-associated hemochromatosis and other iron overload disorders.

• Journal of the Korea Computer Graphics Society
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• v.23 no.3
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• pp.19-29
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• 2017

When a fixed-sized memory allocation method is used for sparse volume data, a considerable memory space is in general wasted, which becomes more serious for a large volume of high resolution. In this paper, in order to reduce such unnecessary memory consumption, we propose a volume representation method to store mostly voxels that represent valid information rather than all voxels in a fixed volume space. Then our method is compared with the conventional static memory allocation method, an octree-based representation, and a voxel hashing method in terms of memory usage and computation speed. In particular, we compare the proposed method and the voxel hashing method with respect to implementation of the GPU-based Marching Cubes algorithm.