No abstract

We test whether the reaction of international stock markets to oil shocks can be justified by current and future changes in real cash flows and/or changes in expected returns. We find that in the postwar period, the reaction of United States and Canadian stock prices to oil shocks can be completely accounted for by the impact of these shocks on real cash flows alone. In contrast, in both the United Kingdom and Japan, innovations in oil prices appear to cause larger changes in stock prices than can be justified by subsequent changes in real cash flows or by changing expected returns.

Traumatic articular cartilage lesions have a limited capacity to heal. We tested the hypothesis that overexpression of a human insulin-like growth factor I (IGF-I) cDNA by transplanted articular chondrocytes enhances the repair of fullthickness (osteochondral) cartilage defects in vivo. Lapine articular chondrocytes were transfected with expression plasmid vectors containing the cDNA for the Escherichia coli lacZ gene or the human IGF-I gene and were encapsulated in alginate. The expression patterns of the transgenes in these implants were monitored in vitro for 36 days. Transfected allogeneic chondrocytes in alginate were transplanted into osteochondral defects in the trochlear groove of rabbits. At three and 14 weeks, the quality of articular cartilage repair was evaluated qualitatively and quantitatively. In vitro, IGF-I secretion by implants constructed from IGF-I-transfected chondrocytes and alginate was 123.2722.3 ng/10 7 cells/24 h at day 4 post transfection and remained elevated at day 36, the longest time point evaluated. In vivo, transplantation of IGF-I implants improved articular cartilage repair and accelerated the formation of the subchondral bone at both time points compared to lacZ implants. The data indicate that allogeneic chondrocytes, transfected by a nonviral method and cultured in alginate, are able to secrete biologically relevant amounts of IGF-I over a prolonged period of time in vitro. The data further demonstrate that implantation of these composites into deep articular cartilage defects is sufficient to augment cartilage defect repair in vivo. These results suggest that therapeutic growth factor gene delivery using encapsulated and transplanted genetically modified chondrocytes may be applicable to sites of focal articular cartilage damage.

We show that the returns to the typical long‐term contrarian strategy implemented in previous studies are upwardly biased because they are calculated by cumulating single‐period (monthly) returns over long intervals. The cumulation process not only cumulates “true” returns but also the upward bias in single‐period returns induced by measurement errors. We also show that the remaining “true” returns to loser or winner firms have no relation to overreaction. This study has important implications for event studies that use cumulative returns to assess the impact of information events.

Electrochemical recycling of carbon dioxide back to fuels and chemicals could be a viable method for CO2 remediation if the efficiency of the process could be improved. One of the key challenges, though, is that the faradaic efficiency is low in the presence of water because water electrolysis is much easier than CO2 electrolysis on most transition metal catalysts. Previous investigators have found that one can eliminate water conversion, by eliminating water from the system, but this has not proven to be practical. Here we present an alternate route, where EMIM-BF4 is used to suppress water electrolysis. We observe that the addition of water to 1-ethyl-3-methyl imidazolium tetrafluoroborate (EMIM-BF4) actually increased the efficiency of CO2 conversion to CO. Indeed we find that little hydrogen is produced on silver in EMIM-Water solutions, provided the water concentration is no more than about 90% by mole. We observe an increase in rate of carbon monoxide (CO) production on silver and platinum as water is added to the electrolyte. We attribute this increase to the hydrolysis of tetrafluoroborate, which releases protons when mixed with water. Protons are shown to accelerate the reduction of CO2 until a critical mole fraction of water is reached.