Diverse modes of 5′‐[4‐(aminoiminomethyl)phenyl]‐[2,2′‐bifuran]‐5‐carboximidamide (DB832) interaction with multi‐stranded DNA structures

The modes of binding of 5′‐[4‐(aminoiminomethyl)phenyl]‐[2,2′‐Bifuran]‐5‐carboximidamide (DB832) to multi‐stranded DNAs: human telomere quadruplex, monomolecular R‐triplex, pyr/pur/pyr triplex consisting of 12 T*(T·A) triplets, and DNA double helical hairpin were studied. The optical adsorption of the ligand was used for monitoring the binding and for determination of the association constants and the numbers of binding sites. CD spectra of DB832 complexes with the oligonucleotides and the data on the energy transfer from DNA bases to the bound DB832 assisted in elucidating the binding modes. The affinity of DB832 to the studied multi‐stranded DNAs was found to be greater (K_ass ≈ 10⁷M^?1) than to the duplex DNA (K_ass ≈ 2 × 10⁵M^?1). A considerable stabilizing effect of DB832 binding on R‐triplex conformation was detected. The nature of the ligand tight binding differed for the studied multi‐stranded DNA depending on their specific conformational features: recombination‐type R‐triplex demonstrated the highest affinity for DB832 groove binding, while pyr/pur/pyr TTA triplex favored DB832 intercalation at the end stacking contacts and the human telomere quadruplex d[AG₃(T₂AG₃)₃] accommodated the ligand in a capping mode. Additionally, the pyr/pur/pyr TTA triplex and d[AG₃(T₂AG₃)₃] quadruplex bound DB832 into their grooves, though with a markedly lesser affinity. DB832 may be useful for discrimination of the multi‐sranded DNA conformations and for R‐triplex stabilization. © 2009 Wiley Periodicals, Inc. Biopolymers 93: 8–20, 2010. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com     

Ultra‐stable phosphoglucose isomerase through immobilization of cellulose‐binding module‐tagged thermophilic enzyme on low‐cost high‐capacity cellulosic adsorbent

One‐step enzyme purification and immobilization were developed based on simple adsorption of a family 3 cellulose‐binding module (CBM)‐tagged protein on the external surface of high‐capacity regenerated amorphous cellulose (RAC). An open reading frame (ORF) Cthe0217 encoding a putative phosphoglucose isomerase (PGI, EC 5.3.1.9) from a thermophilic bacterium Clostridium thermocellum was cloned and the recombinant proteins with or without CBM were over‐expressed in Escherichia coli. The rate constant (k_cat) and Michaelis–Menten constant (K_m) of CBM‐free PGI at 60°C were 2,765 s^?1 and 2.89 mM, respectively. PGI was stable at a high protein concentration of 0.1 g/L but deactivated rapidly at low concentrations. Immobilized CBM (iCBM)‐PGI on RAC was extremely stable at ～60°C, nearly independent of its mass concentration in bulk solution, because its local concentration on the solid support was constant. iCBM‐PGI at a low concentration of 0.001 g/L had a half‐life time of 190 h, approximately 80‐fold of that of free PGI. Total turn‐over number of iCBM‐PGI was as high as 1.1 × 10⁹ mole of product per mole of enzyme at 60°C. These results suggest that a combination of low‐cost enzyme immobilization and thermoenzyme led to an ultra‐stable enzyme building block suitable for cell‐free synthetic pathway biotransformation that can implement complicated biochemical reactions in vitro. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011.     

Hydrolytic properties of a thermostable α‐l‐arabinofuranosidase from Caldicellulosiruptor saccharolyticus

Aims: To characterize of a thermostable recombinant α‐l ‐arabinofuranosidase from Caldicellulosiruptor saccharolyticus for the hydrolysis of arabino‐oligosaccharides to l ‐arabinose. Methods and Results: A recombinant α‐l ‐arabinofuranosidase from C. saccharolyticus was purified by heat treatment and Hi‐Trap anion exchange chromatography with a specific activity of 28·2 U mg^?1. The native enzyme was a 58‐kDa octamer with a molecular mass of 460 kDa, as measured by gel filtration. The catalytic residues and consensus sequences of the glycoside hydrolase 51 family of α‐l ‐arabinofuranosidases were completely conserved in α‐l ‐arabinofuranosidase from C. saccharolyticus. The maximum enzyme activity was observed at pH 5·5 and 80°C with a half‐life of 49 h at 75°C. Among aryl‐glycoside substrates, the enzyme displayed activity only for p‐nitrophenyl‐α‐l ‐arabinofuranoside [maximum k_cat/K_m of 220 m(mol l^?1)^?1 s^?1] and p‐nitrophenyl‐α‐l ‐arabinopyranoside. This substrate specificity differs from those of other α‐l ‐arabinofuranosidases. In a 1 mmol l^?1 solution of each sugar, arabino‐oligosaccharides with 2–5 monomer units were completely hydrolysed to l ‐arabinose within 13 h in the presence of 30 U ml^?1 of enzyme at 75°C. Conclusions: The novel substrate specificity and hydrolytic properties for arabino‐oligosaccharides of α‐l ‐arabinofuranosidase from C. saccharolyticus demonstrate the potential in the commercial production of l ‐arabinose in concert with endoarabinanase and/or xylanase. Significance and Impact of the Study: The findings of this work contribute to the knowledge of hydrolytic properties for arabino‐oligosaccharides performed by thermostable α‐l ‐arabinofuranosidase.     

Optimized 4‐V Spinel Cathode Material with High Energy Density for Li‐Ion Cells Operating at 60 °C

Spinel cathodes comprising 16‐μm, AlPO₄‐coated Li_1.09Mn_1.83Al_0.08O₄ with a high energy density of 1.2 W h cm^‐3 are synthesized via a conventional solid‐state reaction using MnO₂ and Li₂CO₃ at 770 °C for 10 h and using a solution‐based coating method in bulk scale (>20 kg). The cathodes are coated by aluminum phosphate at a thickness of <10 nm. The coated cathodes exhibit a first discharge capacity of 108 mA·h g^‐1 and a coulombic efficiency of >99.8%, and their capacity retention is 78% after 200 cycles at a 0.5C rate in a Li‐ion cell under 60 °C. More importantly, a Li‐ion cell containing the coated cathode does not exhibit a swelling problem after 200 cycles at 60 °C. Transmission and scanning electron microscopy suggest that the uniformly distributed AlPO₄ coating and the possible formation of a solid solution phase along the surface play key roles in enhancing the electrochemical performance of the LiMn₂O₄ spinel at 60 °C.     

Substrate specificity of a recombinant d‐lyxose isomerase from Serratia proteamaculans that produces d‐lyxose and d‐mannose

Aims: Characterization of substrate specificity of a d ‐lyxose isomerase from Serratia proteamaculans and application of the enzyme in the production of d ‐lyxose and d ‐mannose. Methods and Results: The concentrations of monosaccharides were determined using a Bio‐LC system. The activity of the recombinant protein from Ser. proteamaculans was the highest for d ‐lyxose among aldoses, indicating that it is a d‐ lyxose isomerase. The native recombinant enzyme existed as a 54‐kDa dimer, and the maximal activity for d‐ lyxose isomerization was observed at pH 7·5 and 40°C in the presence of 1 mmol l^?1 Mn²⁺. The K_m values for d ‐lyxose, d ‐mannose, d ‐xylulose, and d ‐fructose were 13·3, 32·2, 3·83, and 19·4 mmol l^?1, respectively. In 2 ml of reaction volume at pH 7·5 and 35°C, d ‐lyxose was produced at 35% (w/v) from 50% (w/v) d ‐xylulose by the d‐ lyxose isomerase in 3 h, while d ‐mannose were produced at 10% (w/v) from 50% (w/v) d ‐fructose in 5 h. Conclusions: We identified the putative sugar isomerase from Ser. proteamaculans as a d ‐lyxose isomerase. The enzyme exhibited isomerization activity for aldose substrates with the C2 and C3 hydroxyl groups in the left‐hand configuration. High production rates of d‐ lyxose and d ‐mannose by the enzyme were obtained. Significance and Impact of the Study: A new d‐ lyxose isomerase was found, and this enzyme had higher activity for d ‐lyxose and d ‐mannose than previously reported enzymes. Thus, the enzyme can be applied in industrial production of d ‐lyxose and d ‐mannose.     

New Na‐Ion Solid Electrolytes Na4−xSn1−xSbxS4 (0.02 ≤ x ≤ 0.33) for All‐Solid‐State Na‐Ion Batteries

Sulfide Na‐ion solid electrolytes (SEs) are key to enable room‐temperature operable all‐solid‐state Na‐ion batteries that are attractive for large‐scale energy storage applications. To date, few sulfide Na‐ion SEs have been developed and most of the SEs developed contain P and suffer from poor chemical stability. Herein, discovery of a new structural class of tetragonal Na_4?xSn_1?xSb_xS₄ (0.02 ≤ x ≤ 0.33) with space group I4₁/acd is described. The evolution of a new phase, distinctly different from Na₄SnS₄ or Na₃SbS₄, allows fast ionic conduction in 3D pathways (0.2–0.5 mS cm^?1 at 30 °C). Moreover, their excellent air stability and reversible dissolution in water and precipitation are highlighted. Specifically, TiS₂/Na–Sn all‐solid‐state Na‐ion batteries using Na_3.75Sn_0.75Sb_0.25S₄ demonstrates high capacity (201 mA h (g of TiS₂)^?1) with excellent reversibility.     

Characterization of an ethanol‐tolerant 1,4‐β‐xylosidase produced by Pichia membranifaciens

Aims: The purification and biochemical properties of the 1,4‐β‐xylosidase of an oenological yeast were investigated. Methods and Results: An ethanol‐tolerant 1,4‐β‐xylosidase was purified from cultures of a strain of Pichia membranifaciens grown on xylan at 28°C. The enzyme was purified by sequential chromatography on DEAE cellulose and Sephadex G‐100. The relative molecular mass of the enzyme was determined to be 50 kDa by SDS‐PAGE. The activity of 1,4‐β‐xylosidase was optimum at pH 6·0 and at 35°C. The activity had a K_m of 0·48 ± 0·06 mmol l^?1 and a V_max of 7·4 ± 0·1 μmol min^?1 mg^?1 protein for p‐nitrophenyl‐β‐d ‐xylopyranoside. Conclusions: The enzyme characteristics (pH and thermal stability, low inhibition rate by glucose and ethanol tolerance) make this enzyme a good candidate to be used in enzymatic production of xylose and improvement of hemicellulose saccharification for production of bioethanol. Significance and Impact of the Study: This study may be useful for assessing the ability of the 1,4‐β‐xylosidase from P. membranifaciens to be used in the bioethanol production process.     

Fast and Stable Proton Conduction in Heavily Scandium‐Doped Polycrystalline Barium Zirconate at Intermediate Temperatures

The environmental benefits of fuel cells and electrolyzers have become increasingly recognized in recent years. Fuel cells and electrolyzers that can operate at intermediate temperatures (300–450 °C) require, in principle, neither the precious metal catalysts that are typically used in polymer‐electrolyte‐membrane systems nor the costly heat‐resistant alloys used in balance‐of‐plant components of high‐temperature solid oxide electrochemical cells. These devices require an electrolyte with high ionic conductivity, typically more than 0.01 S cm^?1, and high chemical stability. To date, however, high ionic conductivities have been found in chemically unstable materials such as CsH₂PO₄, In‐doped SnP₂O₇, BaH₂, and LaH_3?2xO_x. Here, fast and stable proton conduction in 60‐at% Sc‐doped barium zirconate polycrystal, with a total conductivity of 0.01 S cm^?1 at 396 °C for 200 h is demonstrated. Heavy doping of Sc in barium zirconate simultaneously enhances the proton concentration, bulk proton diffusivity, specific grain boundary conductivity, and grain growth. An accelerated stability test under a highly concentrated and humidified CO₂ stream using in situ X‐ray diffraction shows that the perovskite phase is stable over 240 h at 400 °C under 0.98 atm of CO₂. These results show great promises as an electrolyte in solid‐state electrochemical devices operated at intermediate temperatures.     

Mixed Phase Solid‐State Plastic Crystal Electrolytes Based on a Phosphonium Cation for Sodium Devices

Na batteries are seen as a feasible alternative technology to lithium ion batteries due to the greater abundance of sodium and potentially similar electrochemical behavior. In this work, mixed phase electrolyte materials based on solid‐state compositions of a tri methylisobutylphosphonium (P_111i4) bis(tri fluromethanesulphonyl)amide (NTf₂) organic ionic plastic crystal (OIPC) and high concentration of NaNTf₂ that support safe, sodium metal electrochemistry are demonstrated. A Na symmetric cell can be cycled efficiently, even in the solid state (at 50 °C and 60 °C), for a 25 mol% (P_111i4NTf₂)–75 mol% NaNTf₂ composition at 0.1 mA cm^?2 for 100 cycles. Thus, these mixed phase materials can be potentially used in Na‐based devices under moderate temperature conditions. It is also investigated that the phase behavior, conductivity, and electrochemical properties of mixtures of NaNTf₂ with this OIPC. It is observed that these mixtures have complex phase behavior. For high compositions of the Na salt, the materials are solid at room temperature and retain a soft solid consistency even at 50 °C with remarkably high conductivity, approaching that of the pure ionic liquid at 50 °C, i.e., 10^?3–10^?2 S cm^?1.     

Oligohis‐tags: mechanisms of binding to Ni2+‐NTA surfaces

Since immobilized metal ion affinity chromatography (IMAC) was first reported, several modifications have been developed. Among them, Ni²⁺ immobilized by chelation with nitrilotriacetic acid (NTA) bound to a solid support has become the most common method for the purification of proteins carrying either a C‐ or N‐terminal histidine (His) tag. Despite its broad application in protein purification, only little is known about the binding properties of the His‐tag, and therefore almost no thermodynamic and kinetic data are available. In this study, we investigated the binding mechanism of His‐tags to Ni²⁺‐NTA. Different series of oligohistidines and mixed oligohistidines/oligoalanines were synthesized using automated solid‐phase peptide synthesis (SPPS). Binding to Ni²⁺‐NTA was analyzed both qualitatively and quantitatively with surface plasmon resonance (SPR) using commercially available NTA sensor chips from Biacore. The hexahistidine tag shows an apparent equilibrium dissociation constant (K_D) of 14 ± 1 nM and thus the highest affinity of the peptides synthesized in this study. Furthermore, we could demonstrate that two His separated by either one or four residues are the preferred binding motifs within hexahis tag. Finally, elongation of these referred motifs decreased affinity, probably due to increased entropy costs upon binding. Copyright © 2009 John Wiley & Sons, Ltd.     

Crystal structure and enhanced activity of a cutinase‐like enzyme from Cryptococcus sp. strain S‐2

The structural and enzymatic characteristics of a cutinase‐like enzyme (CLE) from Cryptococcus sp. strain S‐2, which exhibits remote homology to a lipolytic enzyme and a cutinase from the fungus Fusarium solani (FS cutinase), were compared to investigate the unique substrate specificity of CLE. The crystal structure of CLE was solved to a 1.05 Å resolution. Moreover, hydrolysis assays demonstrated the broad specificity of CLE for short and long‐chain substrates, as well as the preferred specificity of FS cutinase for short‐chain substrates. In addition, site‐directed mutagenesis was performed to increase the hydrolysis activity on long‐chain substrates, indicating that the hydrophobic aromatic residues are important for the specificity to the long‐chain substrate. These results indicate that hydrophobic residues, especially the aromatic ones exposed to solvent, are important for retaining lipase activity. Proteins 2009. © 2009 Wiley‐Liss, Inc.     

Potential anti‐bacterial drug target: Structural characterization of 3,4‐dihydroxy‐2‐butanone‐4‐phosphate synthase from Salmonella typhimurium LT2

3,4‐Dihydroxy‐2‐butanone‐4‐phosphate synthase (DHBPS) encoded by ribB gene is one of the first enzymes in riboflavin biosynthesis pathway and catalyzes the conversion of ribulose‐5‐phosphate (Ru5P) to 3,4‐dihydroxy‐2‐butanone‐4‐phosphate and formate. DHBPS is an attractive target for developing anti‐bacterial drugs as this enzyme is essential for pathogens, but absent in humans. The recombinant DHBPS enzyme of Salmonella requires magnesium ion for its activity and catalyzes the formation of 3,4‐dihydroxy‐2‐butanone‐4‐phosphate from Ru5P at a rate of 199 nmol min^?1 mg^?1 with K_m value of 116 μM at 37°C. Further, we have determined the crystal structures of Salmonella DHBPS in complex with sulfate, Ru5P and sulfate‐zinc ion at a resolution of 2.80, 2.52, and 1.86 Å, respectively. Analysis of these crystal structures reveals that the acidic loop (residues 34–39) responsible for the acid‐base catalysis is disordered in the absence of substrate or metal ion at the active site. Upon binding either substrate or sulfate and metal ions, the acidic loop becomes stabilized, adopts a closed conformation and interacts with the substrate. Our structure for the first time reveals that binding of substrate Ru5P alone is sufficient for the stabilization of the acidic active site loop into a closed conformation. In addition, the Glu38 residue from the acidic active site loop undergoes a conformational change upon Ru5P binding, which helps in positioning the second metal ion that stabilizes the Ru5P and the reaction intermediates. This is the first structural report of DHBPS in complex with either substrate or metal ion from any eubacteria. Proteins 2010. © 2010 Wiley‐Liss, Inc.     

A Self‐Forming Composite Electrolyte for Solid‐State Sodium Battery with Ultralong Cycle Life

Replacing organic liquid electrolyte with inorganic solid electrolytes (SE) can potentially address the inherent safety problems in conventional rechargeable batteries. However, solid‐state batteries (SSBs) have been plagued by the relatively low ionic conductivity of SEs and large charge‐transfer resistance between electrode and SE. Here, a new design strategy is reported for improving the ionic conductivity of SE by self‐forming a composite material. An optimized Na⁺ ion conducting composite electrolyte derived from the Na_{1+ n} Zr₂Si _n P_{3? n} O₁₂ NASICON (Na Super Ionic Conductor) structure is successfully synthesized, yielding ultrahigh ionic conductivity of 3.4 mS cm^?1 at 25 °C and 14 mS cm^?1 at 80 °C. On the other hand, in order to enhance the charge‐transfer rate at the electrode/electrolyte interface, an interface modification strategy is demonstrated by utilization of a small amount of nonflammable and nonvolatile ionic liquid (IL) at the cathode side in SSBs. The IL acts as a wetting agent, enabling a favorable interface kinetic in SSBs. The Na₃V₂(PO₄)₃/IL/SE/Na SSB exhibits excellent cycle performance and rate capability. A specific capacity of ≈90 mA h g^?1 is maintained after 10 000 cycles without capacity decay under 10 C rate at room temperature. This provides a new perspective to design fast ion conductors and fabricate long life SSBs.     

A novel reductive graphene oxide‐based magnetic molecularly imprinted poly(ethylene‐co‐vinyl alcohol) polymers for the enrichment and determination of polychlorinated biphenyls in fish samples

The novel reductive graphene oxide‐based magnetic molecularly imprinted poly(ethylene‐co‐vinyl alcohol) polymers (rGO@m‐MIPs) were successfully synthesized as adsorbents for six kinds of polychlorinated biphenyls (PCBs) in fish samples. rGO@m‐MIPs was prepared by surface molecular imprinting technique. Besides, Fe₃O₄ nanoparticles (NPs) were employed as magnetic supporters, and rGO@Fe₃O₄ was in situ synthesis. Different from functional monomer and cross‐linker in traditional molecularly imprinted polymer, here, 3,4‐dichlorobenzidine was employed as dummy molecular and poly(ethylene‐co‐vinyl alcohol) was adopted as the imprinted polymers. After morphology and inner structure of the magnetic adsorbent were characterized, the adsorbent was employed for disperse solid phase extraction toward PCBs and exhibited great selectivity and high adsorption efficiency. This material was verified by determination of PCBs in fish samples combined with gas chromatography‐mass spectrometry (GC‐MS) method. According to the detection, the low detection limits (LODs) of PCBs were 0.0035–0.0070 µg l⁻¹ and spiked recoveries ranged between 79.90 and 94.23%. The prepared adsorbent can be renewable for at least 16 times and expected to be a new material for the enrichment and determination of PCBs from contaminated fish samples. Copyright © 2015 John Wiley & Sons, Ltd.     

Revealing binding interaction between seven drugs and immobilized β2‐adrenoceptor by high‐performance affinity chromatography using frontal analysis

The development of new approaches to study the affinity between ligands and G‐protein‐coupled receptors proves to be of growing interest for pharmacologists, chemists, and biologists. The aim of this work was to determine the binding of seven drugs to β₂‐adrenoceptors by frontal analysis using immobilized receptor stationary phase. The dissociation constants (K_d) were determined to be (3.16 ± 0.09) × 10^?4 M for salbutamol, (4.29 ± 0.12) × 10^?4 M for terbutaline, (6.19 ± 0.16) × 10^?4 M for methoxyphenamine, (2.11 ± 0.07) × 10^?4 M for tulobuterol, (1.82 ± 0.11) × 10^?4 M for fenoterol, (9.75 ± 0.24) × 10^?6 M formoterol, and (9.84 ± 0.26) × 10^?5 M for clenbuterol. These results showed a good correlation with the data determined by radioligand binding assay. Further investigations revealed that the dissociation constant mainly attributed to the number of hydrogen bonds in the structures of ligands. This study indicates that affinity chromatography using immobilized receptor stationary phase can be used for the direct determination of drug‐receptor binding interactions and has the potential to become a reliable alternative for quantitative studies of ligand–receptor interactions. Copyright © 2013 John Wiley & Sons, Ltd.     

Downstream processing,characterization, and structure–function relationship of solvent‐, detergent‐, psychro‐, thermo‐, alkalistable metalloprotease from metal‐, solvent‐tolerant psychrotrophic Pseudomonas putida SKG‐1 isolate

The purification and characterization of psychro‐thermoalkalistable protease from psychrotrophic Pseudomonas putida isolate is being reported for the first time. A ～53 kDa protease was purified 21.4‐folds with 57.2% recovery by ultrafiltration and hydrophobic interaction chromatography. Kinetic analyses revealed the K_m and V_max to be 1.169 mg mL^?1 and 0.833 mg mL^?1 min^?1, respectively. The k_cat value of 3.05 × 10² s^?1 indicated high affinity and catalytic efficiency toward casein. The protease was most active at pH 9.5 and 40°C, with 100% stability in pH and temperature range of 6.0–11.0 and 10–40°C, respectively. Presence of Zn²⁺ increased the thermostability of protease (at 70°C) by 433%. Ethylene diamine tetra acetic acid (EDTA) and 1,10‐phenanthroline were inhibitory, whereas phenyl methyl sulfonyl fluoride (PMSF), p‐chloro mercuric benzoate (PCMB), and β‐mercaptoethanol were ineffective, revealing the enzyme to be a metalloprotease. Zinc, calcium, iron, nickel, and copper at 1 mM increased the enzyme activity (102–134%). Complete reversion of enzyme inhibition (caused by Ethylene diamine tetra acetic acid [EDTA]) by Zn²⁺ affirmed this enzyme as zinc‐dependent metalloprotease. At 0.1% concentration, Triton X‐100 and Tween 80 slightly increased, while SDS and H₂O₂ reduced the protease activity. In the presence of 0.1% commercial detergents, the enzyme was fairly stable (54–81%). In the presence of organic solvent, the protease was remarkably stable exhibiting 72–191% activities. In contrast, savinase exhibited good stability in the presence of hydrophilic solvents, while chymotrypsin showed elevated activities with benzene, toluene, and xylene only. Circular dichroism analysis revealed the protease as a β‐rich protein, having large fraction (～40%) of β‐sheets. Presence of different environmental conditions altered the β‐content, which accordingly affected the protease activity. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2013     

A comparative study of solid and liquid non‐aqueous phases for the biodegradation of hexane in two‐phase partitioning bioreactors

A comparative study of the performance of solid and liquid non‐aqueous phases (NAPs) to enhance the mass transfer and biodegradation of hexane by Pseudomonas aeruginosa in two‐phase partitioning bioreactors (TPPBs) was undertaken. A preliminary NAP screening was thus carried out among the most common solid and liquid NAPs used in pollutant biodegradation. The polymer Kraton G1657 (solid) and the liquid silicone oils SO20 and SO200 were selected from this screening based on their biocompatibility, resistance to microbial attack, non‐volatility and high affinity for hexane (low partition coefficient: K = C_g/C_NAP, where C_g and C_NAP represent the pollutant concentration in the gas phase and NAP, respectively). Despite the three NAPs exhibited a similar affinity for hexane (K ≈ 0.0058), SO200 and SO20 showed a superior performance to Kraton G1657 in terms of hexane mass transfer and biodegradation enhancement. The enhanced performance of SO200 and SO20 could be explained by both the low interfacial area of this solid polymer (as a result of the large size of commercial beads) and by the interference of water on hexane transfer (observed in this work). When Kraton G1657 (20%) was tested in a TPPB inoculated with P. aeruginosa, steady state elimination capacities (ECs) of 5.6 ± 0.6 g m^?3 h^?1 were achieved. These values were similar to those obtained in the absence of a NAP but lower compared to the ECs recorded in the presence of 20% of SO200 (10.6 ± 0.9 g m^?3 h^?1). Finally, this study showed that the enhancement in the transfer of hexane supported by SO200 was attenuated by limitations in microbial activity, as shown by the fact that the ECs in biotic systems were far lower than the maximum hexane transfer capacity recorded under abiotic conditions. Biotechnol. Bioeng. 2010;106: 731–740. © 2010 Wiley Periodicals, Inc.     

Slurry‐Fabricable Li+‐Conductive Polymeric Binders for Practical All‐Solid‐State Lithium‐Ion Batteries Enabled by Solvate Ionic Liquids

For mass production of all‐solid‐state lithium‐ion batteries (ASLBs) employing highly Li⁺ conductive and mechanically sinterable sulfide solid electrolytes (SEs), the wet‐slurry process is imperative. Unfortunately, the poor chemical stability of sulfide SEs severely restrict available candidates for solvents and in turn polymeric binders. Moreover, the binders interrupt Li⁺‐ionic contacts at interfaces, resulting in the below par electrochemical performance. In this work, a new scalable slurry fabrication protocol for sheet‐type ASLB electrodes made of Li⁺‐conductive polymeric binders is reported. The use of intermediate‐polarity solvent (e.g., dibromomethane) for the slurry allows for accommodating Li₆PS₅Cl and solvate‐ionic‐liquid‐based polymeric binders (NBR‐Li(G3)TFSI, NBR: nitrile?butadiene rubber, G3: triethylene glycol dimethyl ether, LiTFSI: lithium bis(trifluoromethanesulfonyl)imide) together without suffering from undesirable side reactions or phase separation. The LiNi_0.6Co_0.2Mn_0.2O₂ and Li₄Ti₅O₁₂ electrodes employing NBR‐Li(G3)TFSI show high capacities of 174 and 160 mA h g^?1 at 30 °C, respectively, which are far superior to those using conventional NBR (144 and 76 mA h g^?1). Moreover, high areal capacity of 7.4 mA h cm^?2 is highlighted for the LiNi_0.7Co_0.15Mn_0.15O₂ electrodes with ultrahigh mass loading of 45 mg cm^?2. The facilitated Li⁺‐ionic contacts at interfaces paved by NBR‐Li(G3)TFSI are evidenced by the complementary analysis from electrochemical and ⁷Li nuclear magnetic resonance measurements.     

A Supramolecular “Double‐Cable” Structure with a 12944 Helix in a Columnar Porphyrin‐C60 Dyad and its Application in Polymer Solar Cells

A novel porphyrin‐C₆₀ dyad (PCD1) is designed and synthesized to investigate and manipulate the supramolecular structure where geometrically isotropic [such as [60]fullerene (C₆₀)] and anisotropic [such as porphyrin (Por)] units coexist. It is observed that PCD1 possesses an enantiomeric phase behavior. The melting temperature of the stable PCD1 thermotropic phase is 160 °C with a latent heat (ΔH) of 18.5 kJ mol^?1. The phase formation is majorly driven by the cooperative intermolecular Por–Por and C₆₀–C₆₀ interactions. Structural analysis reveals that this stable phase possesses a supramolecular “double‐cable” structure with one p‐type Por core columnar channel and three helical n‐type C₆₀ peripheral channels. These “double‐cable” columns further pack into a hexagonal lattice with a = b = 4.65 nm, c = 41.3 nm, α = β = 90°, and γ = 120°. The column repeat unit is determined to possess a 129₄₄ helix. With both donor (D; Pro) and acceptor (A; C₆₀) units having their own connecting channels as well as the large D/A interface within the supramolecular “double‐cable” structure, PCD1 has photogenerated carriers with longer lifetimes compared to the conventional electron acceptor [6,6]‐phenyl‐C₆₁‐butyric acid methyl ester. A phase‐separated columnar morphology is observed in a bulk‐heterojunction (BHJ) material made by the physical blend of a low band‐gap conjugated polymer, [poly[2,6‐(4,4‐bis‐(2‐ethylhexyl)‐4H‐cyclopenta [2,1‐b;3,4‐b′]‐dithiophene)‐alt‐4,7‐(2,1,3‐benzothia‐diazole)] (PCPDTBT), and PCD1. With a specific phase structure in the solid state and in the blend, PCD1 is shown to be a promising candidate as a new electron acceptor in high performance BHJ polymer solar cells.