Household Activity Pattern Problem with Autonomous Vehicles

Networks and Spatial Economics - The pace of changes in automating cars has sped up in the last few decades. Autonomous Vehicles (AVs) will dramatically change the future of transportation, and...     

Idiosyncratic Drug-Induced Liver Injury: Mechanistic and Clinical Challenges

Idiosyncratic drug-induced liver injury (IDILI) remains a significant problem for patients and drug development. The idiosyncratic nature of IDILI makes mechanistic studies difficult, and little is known of its pathogenesis for certain. Circumstantial evidence suggests that most, but not all, IDILI is caused by reactive metabolites of drugs that are bioactivated by cytochromes P450 and other enzymes in the liver. Additionally, there is overwhelming evidence that most IDILI is mediated by the adaptive immune system; one example being the association of IDILI caused by specific drugs with specific human leukocyte antigen (HLA) haplotypes, and this may in part explain the idiosyncratic nature of these reactions. The T cell receptor repertoire likely also contributes to the idiosyncratic nature. Although most of the liver injury is likely mediated by the adaptive immune system, specifically cytotoxic CD8+ T cells, adaptive immune activation first requires an innate immune response to activate antigen presenting cells and produce cytokines required for T cell proliferation. This innate response is likely caused by either a reactive metabolite or some form of cell stress that is clinically silent but not idiosyncratic. If this is true it would make it possible to study the early steps in the immune response that in some patients can lead to IDILI. Other hypotheses have been proposed, such as mitochondrial injury, inhibition of the bile salt export pump, unfolded protein response, and oxidative stress although, in most cases, it is likely that they are also involved in the initiation of an immune response rather than representing a completely separate mechanism. Using the clinical manifestations of liver injury from a number of examples of IDILI-associated drugs, this review aims to summarize and illustrate these mechanistic hypotheses.     

Determination of atomistic deformation of tricalcium silicate paste with high-volume fly ash

We examined the effect of incorporating high-volume fly ash on the atomic arrangement and interatomic deformation behavior of calcium silicate hydrates in tricalcium silicate paste upon exposure to external forces. The interatomic structural changes and strains under compressive load were assessed using synchrotron in situ high-energy X-ray scattering-based atomic pair distribution function analysis. Three different types of strains, which were (a) macroscopic strains from gauges on the surfaces of specimen, (b) strains in a reciprocal space (Bragg peak shift), and (c) strains in real space (PDF peak shift), were compared to each other. All monitored and calculated strains for tricalcium silicate-fly ash (50 wt% fly ash) paste were compared with the counterparts of the pure tricalcium silicate paste. Pair distribution function analysis in the range of r < 10 Å indicated that the atomic arrangement of tricalcium silicate-fly ash was similar to that of synthetic calcium silicate hydrates followed by that of pure tricalcium silicate paste. Moreover, the pair distribution function refinement results revealed that the calcium silicate hydrate structure in tricalcium silicate-fly ash paste was similar to tobermorite 11 Å, unlike that in pure tricalcium silicate paste. The interatomic strain of tricalcium silicate-fly ash in the real space (r < 20 Å) was smaller than that of tricalcium silicate under compression, which suggested that the incompressibility of calcium silicate hydrates at atomistic scale was enhanced by the incorporation of fly ash into it. This was likely to be caused by the increased silicate polymerization of calcium silicate hydrates, which was attributed to the increase in the amount of silicate in their structure via the addition of fly ash.     

H −/H ∞ sensor fault detection and isolation in linear time-invariant systems

This paper addresses sensor fault detection and isolation problems for continuous- and discrete-time linear time-invariant systems. To that end, we employ a bank consisting of the same number of observers as there are sensors. Both the observer gain and the residual gain are considered. Unlike earlier work, the design conditions with H _?/H _∞ performance are derived in terms of linear, rather than nonlinear, matrix inequalities. An illustrative example is provided to show the effectiveness of the proposed methodology.     

Optimization of conductivity and strength in Cu-Ni-Si alloys by suppressing discontinuous precipitation

Cu-Ni-Si alloys with and without Ti were solution treated at 980 °C for 1 h and cooled by air cooling and water quenching, after which the specimens were aged at 500 °C. The two alloys showed different aging characteristics with different cooling rates during the aging process. The conductivity of all alloys increased during aging; for alloys that were water quenched, hardness increased at the early stage of aging and then drastically decreased. The air-cooled Cu-Ni-Si alloy without Ti also experienced an increase in hardness, which then decreased during aging, but the air-cooled Cu-Ni-Si alloy with Ti did not show a drastic decrease in hardness during prolonged aging. A combination of yield strength and conductivity of 820 MPa and 42% IACS, respectively, was achieved in the air-cooled Cu-Ni-Si-Ti alloy after solution treatment.     

Single-atom Pd catalyst anchored on Zr-based metal-organic polyhedra for Suzuki-Miyaura cross coupling reactions in aqueous media

The challenge for single-atom catalysts in various C-C cross coupling reaction exists in the development of solid supporting materials.It has been desired tofind a supporting material designed in molecular level to anchor a single-atom catalyst and provide high degree of dispersion and substrate access in aqueous media.Here,we prepared discrete cages of metal-organic polyhedra anchoring single Pd atom(MOP-BPY(Pd))and successfully performed a Suzuki-Miyaura cross coupling reaction with various substrates in aqueous media.It was revealed that each tetrahedral cage of MOP-BPY(Pd)has 4.5 Pd atoms on average and retained its high degree of dispersion up to 3 months in water.The coupling efficiencies of the Suzuki-Miyaura cross coupling reaction exhibited more than 90.0%for various substrates we have tested in the aqueous media,which is superior to those of the molecular Pd complex and metal-organic framework(MOF)anchoring Pd atoms.Moreover,MOP-BPY(Pd)was successfully recovered and recycled without performance degradation.     

Experimental study of the fire resistance of walls and floors constructed with steel studs and steel joists

Steel‐framed houses using light‐gauge steel as a structural member have been developed and constructed since the early 2000s as a new construction pattern in the low‐rise construction market in Korea. Generally, the steel frames consist of two major load‐carrying elements such as load‐bearing wall and floor construction made up of approximately 1.0‐mm cold‐formed light‐gauge steel and light‐weight boards. Therefore, the steel frames are very simple to construct and make the construction period shorter than the ordinary construction type or concrete‐based construction. In Korea, regardless of the construction material types, the building regulation requires 1‐h fire rating for apartment buildings of four stories or under. To meet the fire resistance, new models of load‐bearing wall and floor should be developed. From the fire test results, two layer gypsum boards of 12.5 mm in thickness reinforced with glass fiber were proven satisfactory to provide 1‐h fire resistance with load‐bearing wall and floor. Copyright © 2012 John Wiley & Sons, Ltd.     

Nano Si-coated graphite composite anode synthesized by semi-mass production ball milling for lithium secondary batteries

Nano-sized silicon particles were uniformly coated onto a natural graphite surface by a 1 ton/month-based semi-mass production ball milling method in order to prepare Si-based anodes for Li ion batteries. The structure, surface morphology and Si coating properties of the as-synthesized powders were analyzed by XRD, Raman, SEM, TEM and EDS mapping tools. The initial gravimetric discharge capacity of the Si-coated graphite measured using a half cell was 761 mAh/g at a rate of 0.2 C. Additionally, the discharge capacity retention of a full cell system was 71.4% at a 1 C rate even after 300 cycles as well as 96.6% of initial coulombic efficiency. The cycled composite powders were further analyzed by SEM and EDS mapping techniques. This method is proposed for commercial extension to the manufacture of lithium secondary batteries.     

Optimization of conduction-cooled current leads with unsteady operating current

A generalized optimization method is presented for conduction-cooled or cryocooled current leads whose operating current may vary over a period of time. This study is part of our ongoing efforts to reduce the cooling load in HTS power applications, where the actual current level varies considerably over a day and over a year. The presented method is also applicable to superconducting magnets that are not always operational at full current. When the operating current is given as a function of time, the total or accumulated cooling load at the cold end is calculated by integrating the instantaneous load over the period. The optimal length-to-area ratio of conductor is determined to achieve a minimum in the total load. After an accurate procedure taking into full account the temperature-dependent properties of conductor is developed with numerical calculations, a simple and reasonably accurate method based on Wiedemann-Franz approximation is suggested for practical use.