379 research outputs found
Tissue factor pathway inhibitor-2 suppresses the production of active matrix metalloproteinase-2 and is down-regulated in cells harboring activated ras oncogenes
AbstractA human placenta cDNA expression library was screened for genes inducing flat reversion when transfected into a v-K-ras-transformed NIH3T3 cell line, DT. One such gene was found to encode a Kunitz-type serine protease inhibitor, tissue factor pathway inhibitor-2 (TFPI-2). While the TFPI-2 mRNA can be detected in normal human fibroblasts (MRC-5), it is down-regulated in MRC-5 cells expressing an activated H-ras oncogene and in the human fibrosarcoma cell line, HT1080. Restored expression of the TFPI-2 gene in HT1080 cells resulted in the suppression of matrix invasion activity in vitro with concomitant decrease in the relative amount of active matrix metalloproteinase-2 secreted from the cells. When DT cells were cultured in the presence of conditioned medium and extracellular matrix prepared from TFPI-2-transfected HT1080 cells, increased attachment and flat reversion were observed. These results suggest that TFPI-2 may be required for the maintenance of the integrity of extracellular matrix in normal tissues and its down-regulation as a result of oncogene activation may contribute to the malignant phenotypes of tumor cells
Characterization of foreign exchange market using the threshold-dealer-model
We introduce a deterministic dealer model which implements most of the
empirical laws, such as fat tails in the price change distributions, long term
memory of volatility and non-Poissonian intervals. We also clarify the
causality between microscopic dealers' dynamics and macroscopic market's
empirical laws.Comment: 10pages, 5figures, 1table, Proceedings of APFA
Low Frequency Ultrasonic Array Imaging using Signal Post-processing for Concrete Material
The use of ultrasonic arrays for conducting non-destructive evaluation has been drastically increased in recent years. As one of the array imaging, a post-processing beam-forming technique has been proposed that utilizes a complete set of signals of all combinations of transmission and reception elements. This approach is referred to as full matrix capture (FMC) [1]. In FMC, each array element is sequentially used as an emitter and all other array elements are used as receivers. By changing the emitting element, we obtained a set of flaw signals that was used to form the focal beam. The delay-and-sum beam reconstruction based on the post-processing was applied to imaging of internal voids and reinforced steel bars in concrete material. The reconstruction of voids and steels in concrete specimen (400mm x 400mm x 400 mm) was demonstrated using a phased array transducer in the low frequency range. In this study, the array transducer with total 16 elements and center frequency of 50 kHz was developed. The volume fraction of aggregates in concrete was 70 %, and the maximum size of the coarse aggregate was 20 mm. Figure 1 shows the reconstruction result of a slit. For on-site inspection, we introduced a graphics processing unit (GPU) computation to accelerate the post-processing of beam-forming [2]. The flaw detection time was approximately 0.15 s using Geforce GTX880M (NVIDIA)
Response time differences during hand mental rotation
This study explored gender differences in correct response rates and response times on a task involving left or right arrow selection and another involving the transformation of mental rotation of the hand. We recruited 15 healthy, right-handed men (age 24.5 ± 6.4) and 15 healthy, right-handed women (age 21.3 ± 4.9). For the tasks, we used pictures of left and right arrows and 32 hand pictures (left and right, palm and back) placed in cons (each at 45° from 0° to 315°). Hand and arrow pictures alternated and were shown at random. Participants decided as quickly as possible whether each picture was left or right. To compare the time taken for the transformation of mental rotation of the hand, we subtracted the average arrow response time from that for the left and right hand pictures for each participant. Correct response rates did not differ significantly between men and women or left and right for either arrow or hand pictures. Regardless of gender, the response time was longer for the left arrow picture than right arrow picture. The response time for the hand picture was longest for both men and women for pictures at rotation angles that were most difficult to align with participantsâ hands. While there was no difference between menâs responses for left and right hand pictures, the responses of women were longer for left than right hand pictures and also than those of men. These findings suggest that both men and women mainly perform the hand mental rotation task with implicit motor imagery. On the other hand, the gender difference in performance might be explained by the difference in balance with other strategies, such as visual imagery, and by cognitive, neurophysiological, and morphological differences
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