Few-layered transition metal dichalcogenides (TMDs) are known as true two-dimensional materials, with excellent semiconducting properties and strong light–matter interaction. Thus, TMDs are attractive materials for semitransparent and flexible solar cells for use in various applications. Hoewver, despite the recent progress, the development of a scalable method to fabricate semitransparent and flexible solar cells with mono- or few-layered TMDs remains a crucial challenge. Here, we show easy and scalable fabrication of a few-layered TMD solar cell using a Schottky-type configuration to obtain a power conversion efficiency (PCE) of approximately 0.7%, which is the highest value reported with few-layered TMDs. Clear power generation was also observed for a device fabricated on a large SiO2 and flexible substrate, demonstrating that our method has high potential for scalable production. In addition, systematic investigation revealed that the PCE and external quantum efficiency (EQE) strongly depended on the type of photogenerated excitons (A, B, and C) because of different carrier dynamics. Because high solar cell performance along with excellent scalability can be achieved through the proposed process, our fabrication method will contribute to accelerating the industrial use of TMDs as semitransparent and flexible solar cells.

Conventionally, graphene is a poor thermoelectric material with a low figure of merit (ZT) of 10–4–10–3. Although nanostructuring was proposed to improve the thermoelectric performance of graphene, little experimental progress has been accomplished. Here, we carefully fabricated as-grown suspended graphene nanoribbons with quarter-micron length and ∼40 nm width. The ratio of electrical to thermal conductivity was enhanced by 1–2 orders of magnitude, and the Seebeck coefficient was several times larger than bulk graphene, which yielded record-high ZT values up to ∼0.1. Moreover, we observed a record-high electronic contribution of ∼20% to the total thermal conductivity in the nanoribbon. Concurrent phonon Boltzmann transport simulations reveal that the reduction of lattice thermal conductivity is mainly attributed to quasi-ballistic phonon transport. The record-high ratio of electrical to thermal conductivity was enabled by the disparate electron and phonon mean free paths as well as the clean samples, and the enhanced Seebeck coefficient was attributed to the band gap opening. Our work not only demonstrates that electron and phonon transport can be fundamentally tuned and decoupled in graphene but also indicates that graphene with appropriate nanostructures can be very promising thermoelectric materials.

Cu,Zn-superoxide dismutase (SOD1) is a cytosolic antioxidant enzyme, and its mutation has been implicated in amyotrophic lateral sclerosis (ALS), a disease causing a progressive loss of motor neurons. Although the pathogenic mechanism of ALS remains unclear, it is hypothesized that some toxic properties acquired by mutant SOD1 play a role in the development of ALS. We have examined the structural and catalytic properties of an ALS-linked mutant of human SOD1, His43Arg (H43R), which is characterized by rapid disease progression. As revealed by circular dichroism spectroscopy, H43R assumes a stable β-barrel structure in the Cu(2+),Zn(2+)-bound holo form, but its metal-depleted apo form is highly unstable and readily unfolds or misfolds into an irregular structure at physiological temperature. The conformational change occurs as a two-state transition from a nativelike apo form to a denatured apo form with a half-life of ∼0.5 h. At the same time as the denaturation, the apo form of H43R acquires pro-oxidant potential, which is fully expressed in the presence of Cu(2+) and H(2)O(2), as monitored with a fluorogenic probe for detecting pro-oxidant activity. Comparison of d-d absorption bands suggests that the Cu(2+) binding mode of the denatured apo form is different from that of the native holo form. The denatured apo form of H43R is likely to provide non-native Cu(2+) binding sites where the Cu(2+) ion is activated to catalyze harmful oxidation reactions. This study raises the possibility that the structural instability and the resultant Cu-dependent pro-oxidant activity of the apo form of mutant SOD1 may be one of the pathogenic mechanisms of ALS.

The production of secondary metabolites by immobilized living microorganisms was investigated by simulation techniques. The behavior of free cell and immobilized cell reactors for the production of penicillin by P. chrysogenum was compared. This system was chosen as a model system because literature data on growth and production kinetics are available. Simulation results for bioreactors containing P. chrysogenum immobilized by adsorptive techniques demonstrates a potential advantage in productivity for such reactors over conventional fed batch operation. Realization of this advantage requires an understanding of growth and product formation kinetics for immobilized cells as well as development of immobilization technology that will provide stable, high cell loadings.

No abstract