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排序方式: 共有1046条查询结果,搜索用时 11 毫秒
91.
Ji Hye Kim Sein Hwang Ji-Hye Lee Se Seul Im Jaekyoung Son 《International journal of molecular sciences》2022,23(20)
Cumulative studies have indicated that high-dose vitamin C has antitumor effects against a variety of cancers. However, the molecular mechanisms underlying these inhibitory effects against tumorigenesis and metastasis, particularly in relation to pancreatic cancer, are unclear. Here, we report that vitamin C at high concentrations impairs the growth and survival of pancreatic ductal adenocarcinoma (PDAC) cells by inhibiting glucose metabolism. Vitamin C was also found to trigger apoptosis in a caspase-independent manner. We further demonstrate that it suppresses the invasion and metastasis of PDAC cells by inhibiting the Wnt/β-catenin-mediated epithelial-mesenchymal transition (EMT). Taken together, our results suggest that vitamin C has therapeutic effects against pancreatic cancer. 相似文献
92.
Fractionation of the MeOH extract of Homaxinella sp., a marine sponge, led to the isolation of a sodium salt of a new brominated FA (1), two new MG (2 and 4), and a new lysoPC (6). The geometry of the double bonds in 1 and 2 was defined by comparison of the NMR chemical shifts of the allylic carbons, nuclear Overhauser effect spectroscopy correlations
of the allylic protons, and coupling constants of the vinylic protons with those reported. Evidence mainly from NMR and MS
analyses established the planar structures of the compounds. Compounds 1, 2, 4, and 6 were evaluated for cytotoxicity against a panel of five human solid tumor cell lines. Only compound 1 showed moderate activity. 相似文献
93.
Nonvolatile Charge Injection Memory Based on Black Phosphorous 2D Nanosheets for Charge Trapping and Active Channel Layers
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Young Tack Lee Junyeong Lee Hyunsu Ju Jung Ah Lim Yeonjin Yi Won Kook Choi Do Kyung Hwang Seongil Im 《Advanced functional materials》2016,26(31):5701-5707
2D van der Waals atomic crystal materials have great potential for use in future nanoscale electronic and optoelectronic applications owing to their unique properties such as a tunable energy band gap according to their thickness or number of layers. Recently, black phosphorous (BP) has attracted significant interest because it is a single‐component material like graphene and has high mobility, a direct band gap, and exhibits ambipolar transition behavior. This study reports on a charge injection memory field‐effect transistor on a glass substrate, where few‐layer BPs act as the active channel and charge trapping layers, and Al2O3 films grown by atomic layer deposition act as the tunneling and blocking layers. Because of the ambipolar properties of BP nanosheets, both electrons and holes are involved in the charge trapping process, resulting in bilateral threshold voltage shifts with a large memory window of 22 V. Finally, a memory circuit of a resistive‐load inverter is implemented that converts analog signals (current) to digital signals (voltage). Such a memory inverter also shows a clear memory window and distinct memory on/off switching characteristics. 相似文献
94.
GPR55 recognizes several lipid molecules such as lysophosphatidylinositol. GPR55 expression was reported in human monocytes. However, its role in monocyte adhesion and atherosclerosis development has not been studied. The role of GPR55 in monocyte adhesion and atherosclerosis development was investigated in human THP-1 monocytes and ApoE−/− mice using O-1602 (a potent agonist of GPR55) and CID16020046 (a specific GPR55 antagonist). O-1602 treatment significantly increased monocyte adhesion to human umbilical vein endothelial cells, and the O-1602-induced adhesion was inhibited by treatment with CID16020046. O-1602 induced the expression of Mac-1 adhesion molecules, whereas CID16020046 inhibited this induction. Analysis of the promoter region of Mac-1 elucidated the binding sites of AP-1 and NF-κB between nucleotides −750 and −503 as GPR55 responsive elements. O-1602 induction of Mac-1 was found to be dependent on the signaling components of GPR55, that is, Gq protein, Ca2+, CaMKK, and PI3K. In Apo−/− mice, administration of CID16020046 ameliorated high-fat diet-induced atherosclerosis development. These results suggest that high-fat diet-induced GPR55 activation leads to the adhesion of monocytes to endothelial cells via induction of Mac-1, and CID16020046 blockage of GPR55 could suppress monocyte adhesion to vascular endothelial cells through suppression of Mac-1 expression, leading to protection against the development of atherosclerosis. 相似文献
95.
David K. Hsu Kwang-Hee Im Young-Tae Cho Jae-Woung Park Jae-Ki Sim In-Young Yang 《Journal of Mechanical Science and Technology》2002,16(3):292-301
Ultrasound waves interact strongly with the orientation and sequence of the plies in a layup when propagating in the thickness direction of composite laminates. Also the layup orientation greatly influences its properties in a composite laminate. If the layup orientation of a ply is misaligned, it could result in the part being rejected and discarded. Now, most researchers cut a small coupon from the waste edge and use a microscope to optically verify the ply sequences on important parts. This may add a substantial cost to the production since the test is both labor intensive and performed after the part is cured. A nondestructive technique would be very beneficial, which could be used to test the part after curing and requires less time than the optical test. Therefore we have developed, reduced, and implemented a novel ply-by-ply vector decomposition model for composite laminates fabricated from unidirectional plies. This model decomposes the transmission of a linearly polarized ultrasound wave into orthogonal components through each ply of a laminate. High probability is found, by comparisons between the model and tests, in characterizing cured layups of the laminates by using the proposed method. 相似文献
96.
97.
We have evaluated a multichannel transcranial magnetic stimulation (TMS) system using realistic simulations based on the boundary element method (BEM). We investigated various configurations and types of stimulation coils by means of quantitative measures such as targeting accuracy and field concentration. The simulation studies applied to four different head-brain models suggest improved coil types yielding enhanced targeting accuracy and concentrated evoked electric field distribution 相似文献
98.
This paper proposes an improved vascular pattern extraction algorithm for person verification applications. The proposed direction‐based vascular pattern extraction (DBVPE) algorithm is based on the directional information of vascular patterns. It applies two different filters to the input images: row vascular pattern extraction filter (RVPEF) for effective extraction of the abscissa vascular patterns and column vascular pattern extraction filter (CVPEF) for effective extraction of the ordinate vascular patterns. We use the combined output of both filters to obtain the final hand vascular patterns. Unlike the conventional hand vascular pattern extraction algorithm, the directional extraction approach prevents loss of the vascular pattern connectivity. To validate the DBVPE algorithm, we used a prototype system with a DSP processor. The prototype system shows approximately a three‐times better false acceptance rate (FAR) than the conventional single filter algorithm. 相似文献
99.
The present study was conducted to examine the ability of porcine oocytes to achieve male pronuclear (MPN) formation when they are matured and penetrated in vitro under various culture conditions. When cumulus-enclosed oocytes were cultured for 24-48 h in modified Whitten's medium (pH 7.4) supplemented with 10% porcine follicular fluid, 10 IU eCG/ml, and 10 IU hCG/ml (designated mWM-FG), nuclear maturation of oocytes reaching metaphase II was completed by 36 h after the start of culture. However, there were no differences in the proportions (94-95%) of oocytes penetrated in vitro by cryopreserved ejaculated spermatozoa or in the rates (35-45%) of MPN formation between oocytes cultured for 36 and 48 h. When cumulus-enclosed oocytes were cultured for 36 h in mWM-FG supplemented with 2% (v:v) minimal essential medium (MEM) essential amino acids (EAA) with the addition of 0.1 mM glutamine and/or 1% (v:v) MEM nonessential amino acids (NEAA) and inseminated in vitro, 93-97% of oocytes were penetrated regardless of the presence of amino acids during maturation, but the rates of MPN formation were higher in the presence (79-84%) than in the absence (51%) of any amino acids. The addition of EAA+NEAA and/or 0.57 mM cysteine to mWM-FG also did not affect sperm penetration in vitro, while it promoted MPN formation (76-83%) in penetrated oocytes as compared with those matured in the absence of amino acids and cysteine (53%). When oocytes were freed from cumulus cells after culture in mWM-FG, sperm penetration rates were not different between cumulus-enclosed (100%) and cumulus-free (92%) oocytes, but the rate of MPN formation was higher in cumulus-enclosed (53%) than in cumulus-free (28%) oocytes. When EAA+NEAA+cysteine was added to mWM-FG, MPN formation was not improved in cumulus-free oocytes but was much improved (78%) in cumulus-enclosed oocytes. These results indicate that MPN formation in porcine oocytes is promoted by the addition of amino acids and/or cysteine in simple maturation medium and by the presence of cumulus cells at fertilization in vitro. 相似文献
100.
Morphological and morphometric features of the cornea of 13 species of primates have been studied in order to determine possible morphological differences between them. The existence of relationships between different morphometric corneal variables was also examined to establish which variables best defined and characterized the cornea. The present aim is to determine which primate cornea resembles that of the human being most with a view to possible future clinical and experimental studies. The results obtained revealed that all the cornea under study presented similar morphological features. The relationship between total corneal thickness and corneal epithelial thickness was determined as well as the relationship between epithelial thickness, the number of epithelial layers and the number of epithelial cells. However, the morphological pattern of Bowman's membrane and corneal endothelium differed in the species studied. Finally, the study indicates that the chimpanzee and the gorilla are the species with a corneal morphometry which is closest to that of the human cornea. 相似文献