219 research outputs found
Convergence between Wnt-β-catenin and EGFR signaling in cancer
Wnt and EGFR signaling play key roles in embryonic development and cell proliferation. It is well documented that dysregulation of these two pathways often leads to tumorigenesis with poor prognosis. However, the possible crosstalk between the two pathways in cancer development is largely unknown. Although some reports show that EGFR might antagonize Wnt signaling during development in Drosophila, an increasing body of evidence indicates that Wnt and EGFR signaling crosstalk and transactivate one another in development and cancer. This review summarizes recent studies on the crosstalk between Wnt and EGFR signaling in cancers and points out several possible convergence points. Wnt ligands can activate EGFR signaling through their 7-transmembrane domain receptor Frizzled while EGFR can activate β-catenin via receptor tyrosine kinase-PI3K/Akt pathway; EGFR has been shown to form a complex with β-catenin and increase the invasion and metastasis of cancer cells. NKD2, a Wnt antagonist by interacting with Dishevelled, also escorts TGFα-containing exocytic vesicles to the basolateral membrane of polarized epithelial cells. Down-regulation of NKD2 causes Wnt activation and TGFα misdelivery, suggesting its functions in cell homeostasis and prevention of tumorigenesis
Weathering with: Afterlife Treatment of Architecture
When thinking about afterlife of architecture, one would imagine architecture’s incapability of maintain its form due to its deterioration. Humans tear down buildings to construct new buildings, or update building by replacing damaged parts.
However recent study indicates that the traditional human-architecture relationship will end in the near future due to population increase and global warming. As humans lose more and more habitable lands, the remaining architecture on inhabitable lands will be abandoned. This raises the question of who then decides the fate of the abandoned architecture. This thesis sees weathering as the answer to the question and reimagines the human-architecture relationship through the lens of weathering.
This thesis project is interested in proposing an architectural design that accepts weathering architecture and converts conventional modern architecture-- which has been consumed for a certain program and demolished afterward-- to architecture that embraces slow degeneration while interacting with its changing context. The objective of the proposed study is to explore the process of architectural materials being weathered within a certain time frame to contemplate how weathered architecture would fit in a future society.
Oyster shells are the key material for the weathering architecture because of its capability of accommodating marine ecosystem. Its porous surfaces play various roles in each weathering stage, from air purification system to fertilizer for eelgrass. The changing roles are determined by its relationship to the context and specific human activities. The concept of letting architecture components remain the same while changing its functions is based on the project’s design philosophy that human operations will not become the decider of the weathering architecture
A Hybrid Secure Scheme for Wireless Sensor Networks against Timing Attacks Using Continuous-Time Markov Chain and Queueing Model
Wireless sensor networks (WSNs) have recently gained popularity for a wide
spectrum of applications. Monitoring tasks can be performed in various
environments. This may be beneficial in many scenarios, but it certainly
exhibits new challenges in terms of security due to increased data
transmission over the wireless channel with potentially unknown threats. Among
possible security issues are timing attacks, which are not prevented by
traditional cryptographic security. Moreover, the limited energy and memory
resources prohibit the use of complex security mechanisms in such systems.
Therefore, balancing between security and the associated energy consumption
becomes a crucial challenge. This paper proposes a secure scheme for WSNs
while maintaining the requirement of the security-performance tradeoff. In
order to proceed to a quantitative treatment of this problem, a hybrid
continuous-time Markov chain (CTMC) and queueing model are put forward, and
the tradeoff analysis of the security and performance attributes is carried
out. By extending and transforming this model, the mean time to security
attributes failure is evaluated. Through tradeoff analysis, we show that our
scheme can enhance the security of WSNs, and the optimal rekeying rate of the
performance and security tradeoff can be obtained. View Full-Tex
PSweight: An R Package for Propensity Score Weighting Analysis
Propensity score weighting is an important tool for comparative effectiveness
research.Besides the inverse probability of treatment weights (IPW), recent
development has introduced a general class of balancing weights, corresponding
to alternative target populations and estimands. In particular, the overlap
weights (OW) lead to optimal covariate balance and estimation efficiency, and a
target population of scientific and policy interest. We develop the R package
PSweight to provide a comprehensive design and analysis platform for causal
inference based on propensity score weighting. PSweight supports (i) a variety
of balancing weights, (ii) binary and multiple treatments,(iii) simple and
augmented weighting estimators, (iv) nuisance-adjusted sandwich variances,
and(v) ratio estimands. PSweight also provides diagnostic tables and graphs for
covariate balance assessment. We demonstrate the functionality of the package
using a data example from the NationalChild Development Survey (NCDS), where we
evaluate the causal effect of educational attainment on income.Comment: 18 pages, 3 figures, 5 table
Transcriptomic analysis reveals that methyl jasmonate confers salt tolerance in alfalfa by regulating antioxidant activity and ion homeostasis
IntroductionAlfalfa, a globally cultivated forage crop, faces significant challenges due to its vulnerability to salt stress. Jasmonates (JAs) play a pivotal role in modulating both plant growth and response to stressors.MethodsIn this study, alfalfa plants were subjected to 150 mM NaCl with or without methyl jasmonate (MeJA). The physiological parameters were detected and a transcriptomic analysis was performed to elucidate the mechanisms underlying MeJA-mediated salt tolerance in alfalfa.ResultsResults showed that exogenous MeJA regulated alfalfa seed germination and primary root growth in a dose-dependent manner, with 5µM MeJA exerting the most efficient in enhancing salt tolerance. MeJA at this concentration elavated the salt tolerance of young alfalfa seedlings by refining plant growth, enhancing antioxidant capacity and ameliorating Na+ overaccumulation. Subsequent transcriptomic analysis identified genes differentially regulated by MeJA+NaCl treatment and NaCl alone. PageMan analysis revealed several significantly enriched categories altered by MeJA+NaCl treatment, compared with NaCl treatment alone, including genes involved in secondary metabolism, glutathione-based redox regulation, cell cycle, transcription factors (TFs), and other signal transductions (such as calcium and ROS). Further weighted gene co-expression network analysis (WGCNA) uncovered that turquoise and yellow gene modules were tightly linked to antioxidant enzymes activity and ion content, respectively. Pyruvate decar-boxylase (PDC) and RNA demethylase (ALKBH10B) were identified as the most central hub genes in these two modules. Also, some TFs-hub genes were identified by WGCNA in these two modules highly positive-related to antioxidant enzymes activity and ion content.DiscussionMeJA triggered a large-scale transcriptomic remodeling, which might be mediated by transcriptional regulation through TFs or post-transcriptional regulation through demethylation. Our findings contributed new perspectives for understanding the underneath mechanisms by which JA-mediated salt tolerance in alfalfa
Pathogenesis mechanism of Pestalotiopsis funerea toxin (Pf-toxin) on the plasmalemma of needle cells of different pine species
The Pf-toxin (C5H11O5N) has been genetically associated with the pathogenesis mechanism in plasmalemma cells of pine needles in previous reports. In this study, a toxin was obtained from Pestalotiopsis funerea (called Pf- toxin) by concentrating and column chromatography. Responses of the needles of eight pine species against the toxin were investigated. The O2- production rate, malondialdehyde (MDA) content, fatty acid composition, relative conductivity, and lesion length of the needles were determined. The severest damage and lipid peroxidation were exhibited by the needle plasmalemma of Pinus massoniana, Pinus yunnanensis, and Pinus tabuliformis. Pinus elliottii and Pinus taeda followed. Pinus armandi, Pinus radiata and Pinus thunbergii came last. The resistance capability of resistant species against the Pf-toxin precedes that of susceptible species. Keywords: Pestalotiopsis funerea, Pestalotia needle blight, Pinus, resistance. African Journal of Biotechnology Vol. 11(29), pp. 7397-7407, 10 April, 201
A superconducting wireless energiser based on electromechanical energy conversion
A superconducting magnet (SM) can produce high magnetic fields up to a dozen times stronger than those generated by an electromagnet made of normal conductors or a permanent magnet (PM), and thus has attracted increasing research efforts in many domains including medical devices, large scientific equipment, transport, energy storage, power systems, and electric machines. Wireless energisers, e.g., high temperature superconducting (HTS) flux pumps, can eliminate the thermal load from current leads and arc erosion of slip rings, and are thus considered a promising energisation tool for SMs. However, the time-averaged DC output voltage in existing HTS flux pumps is generated by dynamic resistance: the dynamic loss is unavoidable, and the total AC loss will become significant at high frequencies. This study introduces a highly efficient superconducting wireless energizer (SWE) designed specifically for SMs. The SWE takes advantage of the inherent properties of a superconducting loop, including flux conservation and zero DC resistivity. Extensive theoretical analysis, numerical modelling exploiting the H-ϕ formulation, and experimental measurements were conducted to demonstrate the efficiency and efficacy of the novel SWE design. The electromechanical performance and loss characteristics of the SWE system have also been investigated. Compared to conventional HTS flux pumps, the proposed SWE has lower excitation loss, in the order of 10−1 mW, and thus can achieve a high system efficiency of no less than 95%. Furthermore, it has a simpler structure with higher reliability, considered ready for further industrial development. In addition to deepening the understating of the intricate electromechanical dynamics between magnetic dipoles and superconducting circuits, this article provides a novel wireless energisation technique for SMs and opens the way to step changes in future electric transport and energy sectors
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