Hydrogen production through dry reforming of biogas using a porous electrochemical cell: Effects of a cobalt catalyst in the electrode and mixing of air with biogas

This paper reports the performance of porous Gd-doped ceria (GDC) electrochemical cells with Co metal in both electrodes (cell No. 1) and with Ni metal in the cathode and Co metal in the anode (cell No. 2) for CO₂ decomposition, CH₄ decomposition, and the dry reforming reaction of a biogas with CO₂ gas (CH₄ + CO₂ → 2H₂ + 2CO) or with O₂ gas in air (3CH₄ +?1.875CO₂ +?1.314O₂ → 6H₂ +?4.875CO +?0.7515O₂). GDC cell No. 1 produced H₂ gas at formation rates of 0.055 and 0.33?mL-H₂/(min?m²-electrode) per 1?mL-supplied gas/(min?m²-electrode) at 600?°C and 800?°C, respectively, by the reforming of the biogas with CO₂ gas. Similarly, cell No. 2 produced H₂ gas at formation rates of 0.40?mL-H₂/(min?m²) per 1?mL-supplied gas/(min?m²) at 800?°C from a mixture of biogas and CO₂ gas. The dry reforming of a real biogas with CO₂ or O₂ gas at 800?°C proceeded thermodynamically over the Co or Ni metal catalyst in the cathode of the porous GDC cell. Faraday's law controlled the dry reforming rate of the biogas at 600?°C in cell No. 2. This paper also clarifies the influence of carbon deposition, which originates from CH₄ pyrolysis (CH₄ → C + 2H₂) and disproportionation of CO gas (2CO → C + CO₂), on the cell performance during dry reforming. The dry reforming of a biogas with O₂ molecules from air exhibits high durability because of the oxidation of the deposited carbon by supplied air.     

Differential modes of nuclear localization signal (NLS) recognition by three distinct classes of NLS receptors

The targeting of karyophilic proteins to nuclear pores is mediated via the formation of a nuclear pore-targeting complex, through the interaction of nuclear localization signal (NLS) with its NLS receptor. Recently, a novel human protein, Qip1, was identified from a yeast two-hybrid system with DNA helicase Q1. This study demonstrates that Qip1 is a novel third class of NLS receptor that efficiently recognizes the NLS of the helicase Q1. Moreover, the data obtained in this study show that the specific interaction between Qip1 and the NLS of the helicase Q1 requires its upstream sequence of the minimal essential NLS. By using purified recombinant proteins alone in the digitonin-permeabilized cell-free transport system, it was demonstrated that the two known human NLS receptors, Rch1 and NPI-1, are able to transport all the tested NLS substrates into the nucleus, while Qip1 most efficiently transports the helicase Q1-NLS substrates, which contain its upstream sequence in so far as we have examined the system. Furthermore, in HeLa cell crude cytosol, it was found that endogenous Rch1 binds to all the tested NLS substrates, while the binding of endogenous NPI-1 is restricted to only some NLSs, despite the fact that NPI-1 itself shows binding activity to a variety of NLSs. These results indicate that at least three structurally and functionally distinct NLS receptors exist in the human single cell population, and suggest that the nuclear import of karyophilic proteins may be controlled in a complex manner at the NLS recognition step by the existence of a variety of NLS receptors with various specificities to each NLS.     

Atomic force microscopic study on DNA-wrapping for different diameter single-wall carbon nanotubes

DNA-wrapped single-wall carbon nanotubes (DNA-SWNT hybrids) prepared from different diameter HiPco- and Arc-SWNTs were investigated by atomic force microscopy. The mean diameter of DNA-HiPco-SWNT hybrids is 1.94 nm that is consistent with one HiPco-SWNT (~ 0.9 nm) wrapped by DNA (~ 1 nm). On the other hand, the mean diameter of DNA-Arc-SWNT hybrids is 3.74 nm that can correspond to one Arc-SWNT (~ 1.4 nm) wrapped by several layers of DNA. It is suggested that the DNA-wrapping mechanism for large diameter Arc-SWNTs is different from that for small diameter HiPco-SWNTs.     

The rotational angle in osteoarthritic knees

The desire to work is deeply rooted in the human psyche and involves both intrinsic and extrinsic factors. If this is indeed the case, then this form of human activity should be considered to be an important element of our lives and therefore worthy of intervention when circumstances restrict an individual's engagement with it. To investigate the therapeutic nature of work for people with enduring mental health problems, the author conducted a pilot case study of a work rehabilitation scheme in the United Kingdom. The main theme to emerge from the study was that of purposeful activity.     

Cognitive model of team cooperation in en-route air traffic control

Since controller teams are in charge of en-route air traffic control, team cooperation is a key issue for good control performance. We conducted ethnographic field observation at the Tokyo Area Control Center and then analyzed the obtained data to develop a cognitive model of team cooperation in en-route air traffic control. We segmented conversational records, behavioral records, and so on by control unit, and then clarified relations between the segments and identified expert knowledge and judgment behind them. Cognitive processes of controller teams were reconstructed based on a concept of distributed cognition. The analysis revealed that the mutual belief model is applicable to team cooperation processes, the role assignment of tasks within a controller team is implicit and that control plans are implemented smoothly once team situation awareness has been established. A cognitive model of controllers?? team cooperation has been constructed based on these findings.     

An Engineered Biliverdin-Compatible Cyanobacteriochrome Enables a Unique Ultrafast Reversible Photoswitching Pathway

Cyanobacteriochromes (CBCRs) are promising optogenetic tools for their diverse absorption properties with a single compact cofactor-binding domain. We previously uncovered the ultrafast reversible photoswitching dynamics of a red/green photoreceptor AnPixJg2, which binds phycocyanobilin (PCB) that is unavailable in mammalian cells. Biliverdin (BV) is a mammalian cofactor with a similar structure to PCB but exhibits redder absorption. To improve the AnPixJg2 feasibility in mammalian applications, AnPixJg2_BV4 with only four mutations has been engineered to incorporate BV. Herein, we implemented femtosecond transient absorption (fs-TA) and ground state femtosecond stimulated Raman spectroscopy (GS-FSRS) to uncover transient electronic dynamics on molecular time scales and key structural motions responsible for the photoconversion of AnPixJg2_BV4 with PCB (Bpcb) and BV (Bbv) cofactors in comparison with the parent AnPixJg2 (Apcb). Bpcb adopts the same photoconversion scheme as Apcb, while BV4 mutations create a less bulky environment around the cofactor D ring that promotes a faster twist. The engineered Bbv employs a reversible clockwise/counterclockwise photoswitching that requires a two-step twist on ~5 and 35 picosecond (ps) time scales. The primary forward P_fr → P_o transition displays equal amplitude weights between the two processes before reaching a conical intersection. In contrast, the primary reverse P_o → P_fr transition shows a 2:1 weight ratio of the ~35 ps over 5 ps component, implying notable changes to the D-ring-twisting pathway. Moreover, we performed pre-resonance GS-FSRS and quantum calculations to identify the Bbv vibrational marker bands at ~659,797, and 1225 cm⁻¹. These modes reveal a stronger H-bonding network around the BV cofactor A ring with BV4 mutations, corroborating the D-ring-dominant reversible photoswitching pathway in the excited state. Implementation of BV4 mutations in other PCB-binding GAF domains like AnPixJg4, AM1_1870g3, and NpF2164g5 could promote similar efficient reversible photoswitching for more directional bioimaging and optogenetic applications, and inspire other bioengineering advances.     

New Preparation Method of CdS Clusters Encapsulated in Y-Type Zeolites

CdS clusters encapsulated in Y-type zeolite were prepared by a novel technique with non-aqueous systems. The mechanical mixture of CdCl₂· 2.5H₂O crystal with Y-type zeolite was heated at 773 K, followed by the H₂S treatment at 373 K, resulting in the formation of CdS clusters with the size <2.3 nm.     

Sterols ofKalanchoe pinnata: First report of the isolation of both C-24 epimers of 24-alkyl-Δ25-sterols from a higher plant

Eighteen sterols were isolated from the aerial parts ofKalanchoe pinnata (Crassulaceae) including four novel sterols,viz. (24R)-stigmasta-5,25-dien-3β-ol (24-epiclerosterol), (24R)-5α-stigmasta-7,25-dien-3β-ol, 5α-stigmast-24-en-3β-ol, and 25-methyl-5α-ergost-24(28)-en-3β-ol. 24-Epiclerosterol and its Δ⁷-analog occur together with their 24S/β-epimers in the same plant making this the first report of the isolation of both C-24 epimers of Δ²⁵-unsaturated 24-alkylsterols from a non-marine organism. Iodine-catalyzed isomerization of stigmasta-5,24-dien-3β-ol (24-ethyldesmosterol), the main sterol ofK. pinnata, yielded 24-epiclerosterol among other products.     

Preparation of plasma-polymerized membranes from I-(trimethylsilyl)-I-propyne and gas permeability through the membranes

Summary Plasma-polymerized membranes for gas separation were prepared from 1-(trimethylsilyl)-1-propyne. The permeation data of He, H₂ 0₂, N₂, CO₂, and CH₄ through the membranes showed plasma-polymerized 1-(trimethylsilyl)-1-propyne had high permselectivity but low permeability compared with poly[l-(trimethylsilyl)-1-propyne]. This behavior is considered to be due to the crosslinking structure of the plasma-polymerized membrane. The correlation between plasma polymerization conditions and the membrane performance was studied. The optimum condition at which the deposition rate of the plasma polymer is maximized agreed with the optimum value to yield maximum separation factor of gases through the membrane.