Demand for the development of deposition strategies of well-defined metal thin films with good chemical and physical characteristics has been rapidly growing in the field of various electronics applications. For example, copper electro- or electroless deposition has been widely utilized and investigated in microelectronics industry due to its low electrical resistivity and high electromigration resistance, as compared with aluminum. The conventional plating bath for electro- or electrolless copper deposition involves various chemical reagents such as deposition promoter (or inhibiter), brightening and smoothing agent, etc. These additives, typically organic molecules, sometimes cause mechanical problems due to inclusion of such additives during deposition process, and the discharge from the deposition bath can be a serious environmental issue. Therefore, the development of a facile process that enables additive-free deposition of metallic thin films as well as low environmental toxicity is an important challenge for the fabrication of microelectronic elements. In order to sustain the demand for generating multichip packaging systems for future electronic devices, it would be exceedingly useful to develop novel electrochemical deposition strategy with high-throughput capability that would allow stability of electrochemical reaction at higher deposition rate from plating bath without organic additives. In this context, direct metal deposition processes though ion conducting films have been investigated, such as the fabrication of metallic patterns on polymer substrates using ion-doped precursor films. A variety of direct deposition techniques have been introduced by several groups, including ours, 1,2) based on photoinduced chemistry, thermal treatment, and selective chemical reduction for polyimide and other functional polymers. We have also reported a chemical metallization strategy that utilizes electrochemical constructive lithography with post lift-off process, which enables the fabrication of metal patterns on the polyimide substrate. 3) The use of ion-doped precursors has triggered the development of new concept for electrochemical deposition. Herein we report for the first time that metallic thin films can be deposited through polyelectrolyte thin layers placed on the cathode electrode by the diffusion of metallic ions from the interior of polyelectrolyte, which is essentially different to conventional solution-phase electrodeposition processes (Fig. 1). By taking advantage of the cation-exchangeable nature of polyelectrolyte layers used for creation of solid interface, we demonstrate in this study how it is possible to merge the electrochemical deposition at cathode-polyelectrolyte interface and diffusion of cations through polyelectrolytes for development of novel solid electrodeposition (SED) process. As a proof of concept study, we herein present the successful electrochemical deposition of copper and nickel thin films at the interface between an electrode and ion-doped polyelectrolyte layers from the baths containing only metal salts (without any additives). The effect of cation concentration, temperature, and electrochemical deposition conditions on the deposition rate, growth process and morphology of the films has been investigated. Several electrochemical, microscopic and quantitative analysis revealed that the metallic films have been successfully deposited at the cathode-polyelectrolyte interface through ion exchange reaction in the polyelectrolyte layers, the deposition rate of which are determined by ion exchange rate of cations. This strategy offers an opportunity to translate solution-phase electrochemical deposition into a high-throughput, cost-effective, environmentally-friendly process for the fabrication of metal thin films on substrates. 1) Matsumura, Y. Enomoto, T. Tsuruoka, K. Akamatsu, H. Nawafune, Langmuir, 26, 12448-12454 (2010). 2) S. Ikeda, H. Yanagimoto, K. Akamatsu, H. Nawafune, Adv. Funct. Mater., 17, 889-897 (2007). 3) K. Akamatsu, Y. Fukumoto, T. Taniyama, T. Tsuruoka, H. Yanagimoto, H. Nawafune, Langmuir, 27, 11761-11766 (2011). Figure 1
Glucose and xylose are the major components of lignocellulose. Effective utilization of both sugars can improve the efficiency of bioproduction. Here, we report a method termed parallel metabolic pathway engineering (PMPE) for producing shikimate pathway derivatives from glucose-xylose co-substrate. In this method, we seek to use glucose mainly for target chemical production, and xylose for supplying essential metabolites for cell growth. Glycolysis and the pentose phosphate pathway are completely separated from the tricarboxylic acid (TCA) cycle. To recover cell growth, we introduce a xylose catabolic pathway that directly flows into the TCA cycle. As a result, we can produce 4.09 g L-1 cis,cis-muconic acid using the PMPE Escherichia coli strain with high yield (0.31 g g-1 of glucose) and produce L-tyrosine with 64% of the theoretical yield. The PMPE strategy can contribute to the development of clean processes for producing various valuable chemicals from lignocellulosic resources.
Background: Chronic Myeloid Leukemia (CML) is largely treated with BCR-ABL protein targeted drugs called tyrosine kinase inhibitors (TKIs) , imatinib, which have led to dramatical improvement in 2001.Nilotinib and dasatinib were approved as the second new TK inhibitor in 2010, and Radotinib in 2012.However, the only curative treatment for CML is a bone marrow transplant or an allogeneic stem cell transplant.Case: A 42-year-old man was diagnosed CML in June 2011.He had achieved complete cytogenetic response in 5 months later by nilotinib treatment.It did not lead to major molecular response in the 18 th month, and blastic phase of acute promyelocytic leukemia (M3) occurred in the 19 th months.Leukemia cells had both promyelocytic leukemia gene/retinoic acid receptor alpha (PML/RARα) and BCR/ABL translocations.A retinoic acid was administered for M3.The dasatinib was administered for the blast crisis, and remission was obtained.Transplantation: Hematopoietic stem cell transplantation (HSCT) from umbilical cord blood was performed at remission, but it was rejected twice.The third HSCT was succeeded from a sister who had hyperthyroidism.Conclusion: After 2 times of graft failures, HSCT was succeeded.Long plan of treatment is necessary for middle aged CML patients.
Nanoporous CeO2 samples as supports were prepared by chemical dealloying Ce-Al amorphous alloy, followed by synthesis of Au-Pd/CeO2 catalysts. The synthesized Au-Pd/CeO2 catalysts showed higher cat...
Demand for the development of deposition strategies of well-defined metal thin films with good chemical and physical characteristics has been rapidly growing in the field of various electronics applications. The conventional plating bath for electro- or electroless copper deposition involves various chemical reagents such as deposition promoter (or inhibiter), brightening and smoothing agent, etc. These additives, typically organic molecules, sometimes cause mechanical problems due to inclusion of such additives during deposition process, and the discharge from the deposition bath can be a serious environmental issue. Therefore, the development of a facile process that enables additive-free deposition of metallic thin films as well as low environmental toxicity is an important challenge for the fabrication of next generation microelectronic elements. In this context, herein we report that metallic thin films can be deposited through polyelectrolyte thin layers placed on the cathode electrode by the diffusion of metallic ions from the interior of polyelectrolyte, which is essentially different to conventional solution-phase electrodeposition processes (Figure 1). As a proof of concept study, we present the successful electrochemical deposition of copper thin films at the interface between an electrode and ion-doped polyelectrolyte layers from the baths containing only metal salts (without any additives). In the case for the present three-phase electrochemical system consisting of cathode electrode, polyelectrolyte membrane (PE), and electrolyte solution, PE works as an additional interfacial phase, in which metal ions are transferred through ion exchange reaction based on concentration gradient of metal ions bound with sulfonic acid functional groups in PE layer. Most important feature of the use of PE at the electrode surface is their ability for metal ions to be concentrated in inner ion transport channels with high density sulfonic anions inside the channels. In this electrochemical system, reduction of metal ions to form metal atoms (thus metal films) occurs at electrode-PE interface, and ion exchange reaction occurs inside PE and also at the interface between PE and electrolyte solution. Specific characteristics for the present three-phase electrochemical deposition system can be described as follows. In the case that the deposition rate of metals is below maximum ion exchange rate for PE, (1) concentration of metal ions in PE phase remain unchanged due to higher ion exchange rate than deposition rate in this condition, thus enabling constant current and deposition rate during electroplating, and (2) ion transport number is nearly unity in PE phase because sulfonic anions in PE layer can form metal salts in this condition, i.e., there are mostly no protons to be reduced to form hydrogen bubble, where higher current efficiency for metal deposition can be guaranteed. In the current contribution, the effect of cation concentration, temperature, and electrochemical deposition conditions on the current efficiency, deposition rate, growth process and morphology of the films has been investigated. Several electrochemical, microscopic and quantitative analysis revealed that the metallic films have been successfully deposited at the cathode-polyelectrolyte interface, the deposition rate of which are substantially determined by ion exchange rate of cations. This strategy offers an opportunity to translate solution-phase electrochemical deposition into an on-demand, high-throughput, cost-effective, and environmentally-friendly process for the fabrication of microelectronics circuit elements. Figure 1
