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排序方式: 共有118条查询结果,搜索用时 15 毫秒
101.
102.
Samer A. Tadros Yasmin M. Attia Nadine W. Maurice Sally A. Fahim Fatma M. Abdelwahed Samar Ibrahim Osama A. Badary 《International journal of molecular sciences》2022,23(24)
Hepatocellular carcinoma (HCC) is characterized by its high vascularity and metastasis. Thymoquinone (TQ), the main bio-active constituent of Nigella sativa, has shown anticancer and hepatoprotective effects. TQ’s anticancer effect is mediated through miRNA regulation. miR-1-3p plays a significant role in various cancers but its role in HCC invasiveness remains poorly understood. Bio-informatics analysis predicted that the 3′-UTR of TIMP3 is a target for miR-1-3p; Rats were equally divided into four groups: Group 1, the negative control; Group 2 received TQ; Group 3 received DEN; and Group 4 received DEN after pretreatment with TQ. The expression of TIMP3, MMP2, MMP9, and VEGF in rats’ liver was determined immunohistochemically. RT-qPCR was used to measure the miR-1-3p level in rats’ liver, and TIMP3, MMP2, MMP9, and VEGF in the HepG2 cells after being transfected with miR-1-3p mimic or inhibitor; In rats pretreated with TQ, a decreased expression of MMP2, MMP9 and VEGF, and increased expression levels of TIMP3 and miR-1-3p were detected. Treating the HepG2 cells with miR-1-3p mimic led to the upregulation of TIMP3 and downregulation of MMP2, MMP9, and VEGF, and showed a significant delay in wound healing; These results suggested that the anti-angiogenic effect of TQ in HCC may be mediated through the regulation of miR-1-3p. 相似文献
103.
Epameinondas Fritzilas Martin Milanič Sven Rahmann Yasmin A. Rios-Solis 《Algorithmica》2010,56(3):313-332
In many signal processing and data mining applications, we need to approximate a given matrix Y with a low-rank product Y≈AX. Both matrices A and X are to be determined, but we assume that from the specifics of the application we have an important piece of a-priori knowledge:
A must have zeros at certain positions.
In general, different AX factorizations approximate a given Y equally well, so a fundamental question is whether the known zero pattern of A contributes to the uniqueness of the factorization. Using the notion of structural rank, we present a combinatorial characterization
of uniqueness up to diagonal scaling (subject to a mild non-degeneracy condition on the factors), called structural identifiability
of the model. 相似文献
104.
de Vasconcellos LM Oliveira FN Leite Dde O de Vasconcellos LG do Prado RF Ramos CJ Graça ML Cairo CA Carvalho YR 《Journal of materials science. Materials in medicine》2012,23(2):357-364
A porous implant material with adequate pore structure and the appropriate mechanical properties for bone ingrowth has long
been sought. This article presents details of the development, characterization and in vivo evaluations of powder metallurgy-processed
titanium samples exhibiting a dense core with an integrated porous surface for biomedical applications. A space-holder method
was applied to investigate the effects of different percentages and particle sizes of the urea on bone neoformation in 30
rabbits. The samples were previously characterized using scanning electron microscopy and mechanical testing. After 8 and
12 weeks of implantation, bone ingrowth was histologically and histometrically analyzed and push-out testing was performed.
This study demonstrated that the association of a dense core integrated with the greatest number of interconnected pores of
the smallest size is a promising biomaterial for bone tissue engineering. This sample exhibits appropriate mechanical properties
combined with increased bone ingrowth, providing enhanced resistance to displacement. 相似文献
105.
Yasmin Kafai 《AI & Society》1996,10(1):89-100
One of the central issues is how the computer can enter in the learning process. A considerable amount of research has examined how children’s interactions and learning with computational artifacts are situated. A different approach focuses on the learning through computational artifacts: what can and do children learn when making a computational artifact? This paper studies the experience of elementary-school students making computer games to teach fractions to younger students. The analysis addresses how the social interactions and the artifact constructions situated students’ learning experience. The discussion examines the relationships between designing and learning from a situated learning perspective. 相似文献
106.
Shikano Ikkei; Akhtar Yasmin; Isman Murray B.; Rankin Catharine H. 《Canadian Metallurgical Quarterly》2010,124(5):701
The gustatory rejection response of the cabbage looper, Trichoplusia ni (Lepidoptera: Noctuidae), habituates to antifeedant compounds, allowing for the consumption of deterrent yet nontoxic plant materials. In the present study, we demonstrate that habituation to an antifeedant compound (quinine) persists through the moult between larval instars. As an indirect test of whether the memory was protein synthesis-dependent, we tested whether disrupting protein synthesis would block memory reconsolidation after a reminder. The results indicated that disrupting protein synthesis in habituated larvae following a reminder treatment (reexposure to quinine) eliminated the memory for habituation and restored the antifeedant properties of the quinine. We then examined whether the learned memory could be dishabituated and whether this would disrupt or eliminate long-term memory. We show that 6 hr after exposure to a novel/noxious stimulus (a second antifeedent, xanthotoxin) habituated larvae showed a transient dishabituation-like effect in which the quinine deterred feeding again. However, this effect did not permanently eliminate the habituation produced by the extended exposure as larvae tested 72 hr after xanthotoxin exposure again showed a willingness to consume the quinine treated leaves, indicating that the earlier habituation was still present. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
107.
Electrical properties of cellophane and polypyrrole [cello + PPy] composite films were investigated by the two-probe method. The electrical conduction of composite films was studied as a function of voltage, temperature, and percentage content of PPy in the composite films. An attempt was made to use the [cello + PPy] composite films as electrodes in rechargeable batteries. © 1995 John Wiley & Sons, Inc. 相似文献
108.
Fayyaz Muhammad Yasmin Mussarat Sharif Muhammad Raza Mudassar 《Neural computing & applications》2021,33(1):361-391
Neural Computing and Applications - Appearance-based gender classification is one of the key areas in pedestrian analysis, and it has many useful applications such as visual surveillance, predict... 相似文献
109.
Deborah A. Fields Yasmin B. Kafai 《International Journal of Computer-Supported Collaborative Learning》2009,4(1):47-68
Prior studies have shown how knowledge diffusion occurs in classrooms and structured small groups around assigned tasks yet
have not begun to account for widespread knowledge sharing in more native, unstructured group settings found in online games
and virtual worlds. In this paper, we describe and analyze how an insider gaming practice spread across a group of tween players
ages 9–12 years in an after-school gaming club that simultaneously participated in a virtual world called Whyville.net. In
order to understand how this practice proliferated, we followed the club members as they interacted with each other and members
of the virtual world at large. Employing connective ethnography to trace the movements in learning and teaching this practice,
we coordinated data records from videos, tracking data, field notes, and interviews. We found that club members took advantage
of the different spaces, people, and times available to them across Whyville, the club, and even home and classroom spaces.
By using an insider gaming practice, namely teleporting, rather than the more traditional individual person as our analytical
lens, we were able to examine knowledge sharing and diffusion across the gaming spaces, including events in local small groups
as well as encounters in the virtual world. In the discussion, we address methodological issues and design implications of
our findings.
相似文献
Yasmin B. KafaiEmail: |
110.
Yang Zhang Gytis Balilionis Catalina Casaru Colleen Geary Randall E. Schumacker Yasmin H. Neggers Matthew D. Curtner-Smith Mark T. Richardson Phillip A. Bishop James M. Green 《Applied ergonomics》2014
This study examined the separate effects of caffeine and menthol on cognition and mood during simulated firefighting in the heat. Participants (N = 10) performed three trials in a counterbalanced order, either with 400 mg caffeine, menthol lozenges, or placebo. The simulated firefighting consisted of 2 bouts of 20-min treadmill exercise and one bout of 20-min stepping exercise in the heat with two brief 15-min rest periods between each exercise phase. Exercise induced significant dehydration (>3%) and elevated rectal temperature (>38.9 °C), for all three conditions. Neither caffeine nor menthol reduced perceived exertion compared to placebo (p > 0.05). Mood ratings (i.e., alertness, hedonic tone, tension) significantly deteriorated over time (p < 0.05), but there was no difference among the three conditions. Simple reaction time, short-term memory, and retrieval memory did not alter with treatments or repeated evaluations. Reaction accuracy from a math test remained unchanged throughout the experimental period; reaction time from the math test was significantly faster after exposure to the heat (p < 0.05). It is concluded that, exhaustive exercise in the heat severely impacted mood, but minimally impacted cognition. These treatments failed to show ergogenic benefits in a simulated firefighting paradigm in a hot environment. 相似文献