2,245 research outputs found
Distributed Antittack Fault-Tolerant Tracking Control for Vehicle Platoon Systems Under Cyber-Physical Threats
Vehicle platoon systems are considered as automatous vehicles in a platoon-based driving pattern in which a following vehicle follows the preceding vehicle and maintains the desired vehicle spacing. This article investigates the leader-following tracking issue of vehicle platoon systems under cyber-physical threats with the distributed antiattack fault-tolerant tracking control strategy. In this study, vehicle platoon systems, complicated actuator faults in physical layer, and connectivity-mixed attacks in the cyber layer are modeled, respectively. Decentralized fault-estimation unknown input observer and distributed antiattack fault-tolerant tracking control designs are developed in an integrated control framework to guarantee the robust and resilient tracking property of estimation errors and platoon tracking errors as well as the reliable intervehicle spacing by virtue of attack activation rate and attack frequency metrics. Simulations validate the proposed distributed antiattack fault-tolerant tracking control algorithm in pernicious cyber-physical threatened scenarios
Bi- and tri-dentate imino-based iron and cobalt pre-catalysts for ethylene oligo-/polymerization
Recent progress on the use of iron and cobalt complex pre-catalysts for ethylene reactivity is reviewed. The review is organized in terms of the denticity of the chelate ligands employed, with particular reference to the influence of the ligand frameworks and their substituents on the catalytic performance for ethylene oligomerization/polymerization catalysis. The majority of the systems bear tri-dentate ligation at the iron/cobalt centre, though it is clear that bi-dentate iron/cobalt complex pre-catalysts have also attracted significant attention. Such systems produce in most cases highly linear products ranging from oligomeric α-olefins to high molecular weight polyethylene, and as such are promising candidates for both academic and industrial considerations
Ursolic Acid Florotriazole Treatment Causes Inhibition of Squamous Cell Carcinoma through Fas Signaling Pathway
Purpose: To investigate the effect of ursolic acid florotriazole (UFT), on SCC-15 oral squamous cancer cells.Methods: Confocal laser microscope with a 490 nm argon laser was used to record the fluorescence of the cells and capture the images. Flow cytometry and Cell Quest program were used to analyze the DNA content of the stained cells. Apoptosis was characterized by YO-PRO-1 staining.Results: Treatment of SCC-15 cells with UFT for 48 h significantly reduced cell viability in a dosedependent manner. At 20 μg/mL concentration of UFT, SCC-15, cell viability was reduced to 19 % compared to 100 % in the untreated cells (p = 0.0002). UFT treatment enhanced the proportion of apoptotic cells which was evident from YO-PRO-1 staining. In UFT-treated cultures, the population of cells in sub-G1 phase increased to 38.54 % compared to 7.32 % for control after 48 h. Expression of Fas in UFT-treated cells was also higher (p = 0.0002) than in untreated cells. In C3H/HeJ mice, administration of UFT daily for 14 days caused a significant (p = 0.0002) reduction in tumor volume and weight after 30 days of SCC-15 carcinoma cell administration.Conclusion: UFT treatment inhibits viability and induces apoptosis in squamous cell carcinoma cells through suppression of Fas expression. Therefore, UFT may be useful for the treatment of squamous cell cancer.Keywords: Ursolic acid florotriazole, Squamous cell cancer, Fas expression, Tumor volume, Cell viability, Apoptosi
Pannexin1 Channels Dominate ATP Release in the Cochlea Ensuring Endocochlear Potential and Auditory Receptor Potential Generation and Hearing
Pannexin1 (Panx1) is a gap junction gene in vertebrates whose proteins mainly function as non-junctional channels on the cell surface. Panx1 channels can release ATP under physiological conditions and play critical roles in many physiological and pathological processes. Here, we report that Panx1 deficiency can reduce ATP release and endocochlear potential (EP) generation in the cochlea inducing hearing loss. Panx1 extensively expresses in the cochlea, including the cochlear lateral wall. We found that deletion of Panx1 in the cochlear lateral wall almost abolished ATP release under physiological conditions. Positive EP is a driving force for current through hair cells to produce auditory receptor potential. EP generation requires ATP. In the Panx1 deficient mice, EP and auditory receptor potential as measured by cochlear microphonics (CM) were significantly reduced. However, no apparent hair cell loss was detected. Moreover, defect of connexin hemichannels by deletion of connexin26 (Cx26) and Cx30, which are predominant connexin isoforms in the cochlea, did not reduce ATP release under physiological conditions. These data demonstrate that Panx1 channels dominate ATP release in the cochlea ensuring EP and auditory receptor potential generation and hearing. Panx1 deficiency can reduce ATP release and EP generation causing hearing loss
Mathematical Model to Predict Preheating Time and Temperature Profile in Boxed-Heart Square Timber during Preheating
The objective of this study was to develop a two-dimensional mathematical model that can beused to calculate the heat transfer in larch boxed-heart square timber during the preheating process. The preheating time obtained with the calculations agreed with the experimental results. Both experiments and calculations indicated that it took about 6.5 h for the center of the timbers (120 mm thick 120 mm wide) to reach ambient temperature, suggesting that the model can be used to accurately estimate preheating times. During the preheating process, the simulated core temperature of the wood agreed with the experimental result. However, for the remaining locations, the relative error was rather large, with the value first increasing and then decreasing with time. Therefore, the model can only be used to accurately estimate temperature at the core region of the wood. Furthermore, the results suggested that MC had no significant effect on preheating time
Changes of Nuclear Matrix Proteins Following the Differentiation of Human Osteosarcoma MG-63 Cells
Human osteosarcoma MG-63 cells were induced into differentiation by 5mmol/L hexamethylene bisacetamide (HMBA). Their nuclear matrix proteins (NMPs) were selectively extracted and subjected to two-dimensional gel electrophoresis analysis. The results of protein patterns were analyzed by Melanie software. The spots of differentially expressed NMPs were excised and subjected to in situ digestion with trypsin. The maps of peptide mass fingerprinting were obtained by MALDI-TOF-MS analysis, and were submitted for NCBI database searches by Mascot tool. There were twelve spots changed remarkably during the differentiation induced by HMBA, nine of which were identified. The roles of the regulated proteins during the MG-63 differentiation were analyzed. This study suggests that the induced differentiation of cancer cells is accompanied by the changes of NMPs, and confirms the presence of some specific NMPs related to the cancer cell proliferation and differentiation. The changed NMPs are potential markers for cancer diagnosis or targets for cancer therapy
Hydrate-based CO2 (carbon dioxide) capture from IGCC (integrated gasification combined cycle) synthesis gas using bubble method with a set of visual equipment
The hydrate-based carbon dioxide (CO2) capture from the integrated gasification combined cycle (IGCC) synthesis gas using the bubble method is investigated with a set of visual equipment in this work. The gas bubble is created with a bubble plate on the bottom of the equipment. By the visual equipment, the hydrate formation and the hydrate shape are visually captured. With the move of the gas bubble from the bottom to the top of the reactor, gas hydrate forms firstly from the gas-liquid boundary around the bubble, then the hydrate gradually grows up and piles up in the bottom side of the bubble to form a hydrate particle. The gas hydrate shape is affected by the gas flow rate. The hydrate is acicular crystal at the low gas flow rate while the hydrate is fine sand-like crystal at the high gas flow rate. The bubble size and the gas flow rate have an obvious impact on the hydrate-based CO2 separation process. The experimental results show the gas bubble of 50 mu m and the gas flow rate of 6.75 mL/min/L are ideal for CO2 capture from IGCC synthesis gas under the condition of 3.0 MPa and 274.15 K. (C) 2012 Elsevier Ltd. All rights reserved.</p
1-[3-MethÂoxy-4-(prop-2-yn-1-ylÂoxy)phenÂyl]ethanone
In the title compound, C12H12O3, the methÂoxy and prop-2-ynÂyloxy groups are nearly coplanar with the attached benzene ring [C—O—C—C torsion angles = 1.2 (3) and 2.2 (3)°, respectively]. In the crystal, inversion dimers linked by pairs of C—H⋯O interÂactions occur
A convenient tandem one-pot synthesis of donor-acceptor-type triphenylene 2,3-dicarboxylic esters from diarylacetylene
A tandem one-pot method for the direct synthesis of polysubstituted triphenylene 2,3-dicarboxylic esters with different substitution patterns was developed by enyne metathesis of diarylacetylene, followed by Diels–Alder, aromatization and a cyclization cascade
Suspension and Measurement of Graphene and Bi2Se3 Atomic Membranes
Coupling high quality, suspended atomic membranes to specialized electrodes
enables investigation of many novel phenomena, such as spin or Cooper pair
transport in these two dimensional systems. However, many electrode materials
are not stable in acids that are used to dissolve underlying substrates. Here
we present a versatile and powerful multi-level lithographical technique to
suspend atomic membranes, which can be applied to the vast majority of
substrate, membrane and electrode materials. Using this technique, we
fabricated suspended graphene devices with Al electrodes and mobility of 5500
cm^2/Vs. We also demonstrate, for the first time, fabrication and measurement
of a free-standing thin Bi2Se3 membrane, which has low contact resistance to
electrodes and a mobility of >~500 cm^2/Vs
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