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Solid polymer electrolytes (SPEs) are suitable materials for safety enhancements of high-energy-density lithium metal batteries. Low ionic conductivity and poor interfacial compatibility could be the major issues to be addressed for SPEs. In this work, a cross-linked polybenzoxazine polymer with poly(ethylene oxide) (PEO) segments (CR-PEO-PBz) has been synthesized and used as a polymeric matrix for preparation of SPEs. The cross-linked structure contributes to suppression of PEO crystallization. PEO-PBz is also used as a binder to reduce the interfacial resistance between the electrode and the electrolyte. The features enhance the lithium ion transportation and increase the ionic conductivity of the corresponding SPE (5.32 × 10–¹ mS cm–¹ at 60 °C). CR-PEG-PBz also exhibits the ability to prevent lithium dendrite growth with promotion of uniform lithium deposition. The LiFePO₄/Li coin cells made with the SPEs demonstrate a high initial capacity of 142 mAh g–¹ at 0.2C and 60 °C and a 93% initial capacity after a 100-cycle test. The cells could be operated at 30, 40, and 50 °C, thus proving the capability of the SPE at various temperatures.

// Mei Chao 1,2,3 , Tzu-Chi Wang 2,* , Chia-Chi Lin 2 , Robert Yung-Liang Wang 2,4 , Wen-Bin Lin 2 , Shang-En Lee 2 , Ying-Yu Cheng 2 , Chau-Ting Yeh 3 and Shan-Bei Iang 2 1 Department of Microbiology and Immunology, Chang Gung University, Guishan, Taoyang, Taiwan 2 Division of Microbiology, Graduate Institute of Biomedical Sciences, Chang Gung University, Guishan, Taoyang, Taiwan 3 Department of Hepato-Gastroenterology, Liver Research Center, Chang Gung Memorial Hospital, Guishan, Taoyang, Taiwan 4 Department of Biomedical Sciences, Chang Gung University, Guishan, Taoyang, Taiwan * Deceased Correspondence to: Mei Chao, email: // Keywords : hepatitis delta virus, mammalian RNA polymerase, ribozyme, RNA recombination, template-switching, Immunology and Microbiology Section, Immune response, Immunity Received : November 09, 2016 Accepted : May 22, 2017 Published : June 01, 2017 Abstract The genome of hepatitis delta virus (HDV) is a 1.7-kb single-stranded circular RNA that folds into an unbranched rod-like structure and has ribozyme activity. HDV redirects host RNA polymerase(s) (RNAP) to perform viral RNA-directed RNA transcription. RNA recombination is known to contribute to the genetic heterogeneity of HDV, but its molecular mechanism is poorly understood. Here, we established a whole-genome HDV-1/HDV-4 recombination map using two cloned sequences coexisting in cultured cells. Our functional analyses of the resulting chimeric delta antigens (the only viral-encoded protein) and recombinant genomes provide insights into how recombination promotes the genotypic and phenotypic diversity of HDV. Our examination of crossover distribution and subsequent mutagenesis analyses demonstrated that ribozyme activity on HDV genome, which is required for viral replication, also contributes to the generation of an inter-clade junction. These data provide circumstantial evidence supporting our contention that HDV RNA recombination occurs via a replication-dependent mechanism. Furthermore, we identify an intrinsic asymmetric bulge on the HDV genome, which appears to promote recombination events in the vicinity. We therefore propose a mammalian RNAP-driven and viral-RNA-structure-promoted template-switching mechanism for HDV genetic recombination. The present findings improve our understanding of the capacities of the host RNAP beyond typical DNA-directed transcription.

This work studied the foaming behavior of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) in supercritical carbon dioxide (scCO 2 ). The effects of foaming temperature, foaming pressure, saturation time, depressurization time on the foam structure and crystallinity of samples were investigated. The foaming ability varies with different combinations of the foaming temperature and foaming pressure. However, a lower foaming temperature and a higher foaming pressure are more favorable for obtaining uniform foam than a higher foaming temperature and a lower foaming pressure. At a given foaming temperature and saturation time, increasing the foaming pressure leads to the decreased crystallinity and an increase in the melting temperature.

In this study, solid–liquid equilibria of dicarboxylic acids for binary mixtures, hexanedioic acid (1) + octanedioic acid (2) (eutectic temperature TE = 390.54 K, eutectic composition x1E = 0.419); hexanedioic acid (1) + nonanedioic acid (2) (TE = 372.52 K, x1E = 0.269); hexanedioic acid (1) + decanedioic acid (2) (TE = 387.43 K, x1E = 0.514); heptanedioic acid (1) + octanedioic acid (2) (TE = 365.81 K, x1E = 0.782); heptanedioic acid (1) + nonanedioic acid (2) (TE = 352.50 K, x1E = 0.558); heptanedioic acid (1) + decanedioic acid (2) (TE = 367.07 K, x1E = 0.753); octanedioic acid (1) + decanedioic acid (2) (TE = 387.97 K, x1E = 0.465); nonanedioic acid (1) + octanedioic acid (2) (TE = 367.62 K, x1E = 0.712); and nonanedioic acid (1) + decanedioic acid (2) (TE = 370.49 K, x1E = 0.687), are measured using differential scanning calorimetry and correlated using Clarke-Glew equation. An observation here is simple eutectic phase diagrams for these systems. It can be noted that experiment results, correlated wi...

This research focuses on measuring the solubility of three antioxidants—ethylenediaminetetraacetic acid disodium salt hydrate, ethylenediaminetetraacetic acid calcium disodium salt hydrate, and l-cysteine hydrochloride—in supercritical carbon dioxide. Using a semiflow apparatus, the experiment takes data at 308.15, 313.15, and 318.15 K with pressure ranging from 10 to 22 MPa (for ethylenediaminetetraacetic acid disodium salt dihydrate) or from 12 to 24 MPa (for ethylenediaminetetraacetic acid calcium disodium salt hydrate and l-cysteine hydrochloride). Two semiempirical equations—one proposed by Chrastil, the other Mendez-Santiago and Teja—are applied to find the correlated relationship of the experimental data. With the choice of fitted parameters, the correlation derived from the two equations are satisfactory: the average absolute relative deviation is under 5.1%.

Methane-producing archaea and methylotrophic bacteria use tetrahydromethanopterin (H4MPT) and/or tetrahydrofolate (H4F) as coenzymes in one-carbon (C1) transfer pathways. The α-proteobacterium Methylobacterium extorquens AM1 contains a dihydromethanopterin reductase (DmrA) and two annotated dihydrofolate reductases (DfrA and DfrB). DmrA has been shown to catalyze the final step of H4MPT biosynthesis; however, the functions of DfrA and DfrB have not been examined biochemically. Moreover, sequence alignment (BLAST) searches have recognized scores of proteins that share up to 99% identity with DmrA but are annotated as diacylglycerol kinases (DAGK). In this work, we used bioinformatics and enzyme assays to provide insight into the phylogeny and substrate specificity of selected Dfr and DmrA homologs. In a phylogenetic tree, DmrA and homologs annotated as DAGKs grouped together in one clade. Purified histidine-tagged versions of the annotated DAGKs from Hyphomicrobium nitrativorans and Methylobacterium nodulans (respectively, sharing 69% and 84% identity with DmrA) showed only low activity in phosphorylating 1,2-dihexanoyl-sn-glycerol when compared with a commercial DAGK from E. coli. However, the annotated DAGKs successfully reduced a dihydromethanopterin analog (dihydrosarcinapterin, H2SPT) with kinetic values similar to those determined for M. extorquens AM1 DmrA. DfrA and DfrB showed little or no ability to reduce H2SPT under the conditions studied; however, both catalyzed the NADPH-dependent reduction of dihydrofolate. These results provide the first evidence that DfrA and DfrB function as authentic dihydrofolate reductases, while DAGKs with greater than 69% identity to DmrA may be misannotated and are likely to function in H4MPT biosynthesis.

Solid–liquid equilibria of dicarboxylic acids for binary mixtures—nonanedioic acid (1) + 3-methylheptanedioic acid (2) (eutectic temperature TE = 342.25 K, eutectic composition x1E = 0.364); nonanedioic acid (1) + 2,2-dimethylbutanedioic acid (2) (TE = 367.51 K, x1E = 0.653); nonanedioic acid (1) + 2,3-dimethylbutanedioic acid (2) (TE = 354.27 K, x1E = 0.463); decanedioic acid (1) + 3-methylheptanedioic acid (2) (TE = 352.47 K, x1E = 0.134); decanedioic acid (1) + 2,2-dimethylbutanedioic acid (2) (TE = 384.38 K, x1E = 0.483); and decanedioic acid (1) + 2,3-dimethylbutanedioic acid (2) (TE = 365.38 K, x1E = 0.192)—are measured using differential scanning calorimetry (DSC) and correlated using the Clarke–Glew equation in this study. Simple eutectic phase diagrams for these systems are observed. The experimental results are correlated using the Wilson and nonrandom two-liquid (NRTL) activity coefficient models, and satisfactory results are presented.

Dihydromethanopterin reductase (Dmr) is a redox enzyme that plays a key role in generating tetrahydromethanopterin (H4MPT) for use in one-carbon metabolism by archaea and some bacteria. DmrB is a bacterial enzyme understood to reduce dihydromethanopterin (H2MPT) to H4MPT using flavins as the source of reducing equivalents, but the mechanistic details have not been elucidated previously. Here we report the crystal structure of DmrB from Burkholderia xenovorans at a resolution of 1.9 Å. Unexpectedly, the biological unit is a 24-mer composed of eight homotrimers located at the corners of a cubic cage-like structure. Within a homotrimer, each monomer-monomer interface exhibits an active site with two adjacently bound flavin mononucleotide (FMN) ligands, one deeply buried and tightly bound and one more peripheral, for a total of 48 ligands in the biological unit. Computational docking suggested that the peripheral site could bind either the observed FMN (the electron donor for the overall reaction) or the pterin, H2MPT (the electron acceptor for the overall reaction), in configurations ideal for electron transfer to and from the tightly bound FMN. On this basis, we propose that DmrB uses a ping-pong mechanism to transfer reducing equivalents from FMN to the pterin substrate. Sequence comparisons suggested that the catalytic mechanism is conserved among the bacterial homologs of DmrB and partially conserved in archaeal homologs, where an alternate electron donor is likely used. In addition to the mechanistic revelations, the structure of DmrB could help guide the development of anti-obesity drugs based on modification of the ecology of the human gut.

The central task of this research is devoted to the measurement of the solubility of two antioxidants—d-isoascorbic acid and calcium l-ascorbate dihydrate—in supercritical carbon dioxide. The experiment, using a semiflow type apparatus, takes data at various temperatures, over pressures ranging from 12 MPa to 24 MPa. The acquired data are then processed numerically—with the aid of semiempirical equations proposed by Chrastil and by Mendez-Santiago and Teja—to find the correlated relationship. The correlated results from both equations yield satisfactory results with an average absolute relative deviation (AARD) under 5 % when optimally fitted parameters are chosen.

Solid–liquid equilibrium data for six organic binary mixtures of heptanedioic acid (1) + pentanedioic acid (2) (eutectic temperature TE = 341.9 K, eutectic composition x1E = 0.391), hexanedioic acid (1) + heptanedioic acid (2) (TE = 365.4 K, x1E = 0.239), heptanedioic acid (1) + 2,3-dimethylbutanedioic acid (2) (TE = 348.9 K, x1E = 0.443), heptanedioic acid (1) + 2,2-dimethylbutanedioic acid (2) (TE = 358.8 K, x1E = 0.667), heptanedioic acid (1) + 3-methylpenetandioic acid (2) (TE = 338.8 K, x1E = 0.357), and 2,2-dimethylbutanedioic acid (1) + 3-methylpenetandioic acid (2) (TE = 348.3 K, x1E = 0.212) were measured in this study using differential scanning calorimetry (DSC). All six systems show simple eutectic behavior. The experimental data were correlated using the Wilson and nonrandom two-liquid (NRTL) activity coefficient models, and satisfactory results are presented.

Solid–liquid equilibria for three organic binary mixtures of benzoic acid (1) + heptanedioic acid (2) (eutectic temperature TE = 350.20 K, eutectic composition x1E = 0.498), benzoic acid (1) + 3-methylpentanedioic acid (3) (TE = 340.03 K, x1E = 0.427), and benzoic acid (1) + 2,3-dimethylbutanedioic acid (4) (TE = 352.71 K, x1E = 0.462) were measured using differential scanning calorimetry (DSC). We observe simple eutectic behaviors for all three binary mixtures. The experimental results were further correlated using the Wilson and nonrandom two-liquid (NRTL) activity coefficient models. The optimally fitted binary interaction parameters are reported, and satisfactory correlation results are depicted.

Solid−liquid equilibria for three organic binary mixtures of hexanedioic acid (1) + benzoic acid (2) (eutectic temperature TE = 378.17 K, eutectic composition x1E = 0.249), benzoic acid (1) + pentanedioic acid (2) (TE = 343.50 K, x1E = 0.402), and hexanedioic acid (1) + pentanedioic acid (2) (TE = 355.87 K, x1E = 0.205) were measured using differential scanning calorimetry (DSC). Simple eutectic behaviors for these systems were observed. The experimental results were correlated using the Wilson and nonrandom two-liquid (NRTL) activity coefficient models with satisfactory results.

Theoretical models to predict the upper/lower flammability limits of a mixture composed of hydrocarbon and inert carbon dioxide are proposed in this study. It is found theoretically that there are linear relations between the reciprocal of the upper/lower flammability limits and the reciprocal of the molar fraction of hydrocarbon in the hydrocarbon/inert gas mixture. These theoretical linear relations are examined by existing experimental results reported in the literature, which include the cases of methane, propane, ethylene, and propylene. The coefficients of determination (R(2)) of the regression lines are found to be larger than 0.959 for all aforementioned cases. Thus, the proposed models are highly supported by existing experimental results. A preliminary study also shows the conclusions in present work have the possibility to extend to non-hydrocarbon flammable materials or to inert gas other than carbon dioxide. It is coincident that the theoretical model for the lower flammability limit (LFL) in present work is the same as the empirical model conjectured by Kondo et al.

Most RNA viruses encode their own RNA polymerases for genome replication, and increasing numbers of them appear to be capable of undergoing RNA recombination. Here, we provide the first report of intergenotypic recombination in hepatitis delta virus (HDV), the only animal RNA virus that requires host RNA polymerase(s) for viral replication. In vivo, we analyzed RNA species derived from the serum of a patient with mixed genotype I and genotype IIb HDV infection by using multiple restriction fragment length polymorphism (RFLP) assays and sequence analysis of cloned reverse transcription (RT)-PCR products. Six HDV recombinants were isolated from 101 tested clones, and HDV recombination in this patient was further confirmed by RT-PCR with genotype-specific primer pairs. Analysis of the recombination junctions suggested that the HDV genome rearrangement occurred through faithful homologous recombination. We then used an RNA cotransfection cell culture system to investigate HDV RNA recombination in vitro. We found that HDV recombinants could indeed be detected in the transfected cells; some of these possessed recombination junctions identical to those identified in vivo. Furthermore, using a PCR-independent RNase protection assay, we were able to readily identify the recombined HDV RNA species in cultured cells. Taken together, our results demonstrate that HDV RNA recombination occurs in both natural HDV infections and cultured cells, thereby presenting a novel mechanism for HDV evolution.

Theoretical models to predict the upper/lower flammability limits of hydrocarbons diluted with inert nitrogen gas are proposed in this study. It is found that there are linear relations between the reciprocal of the upper/lower flammability limits and the reciprocal of the molar fraction of hydrocarbon in the hydrocarbon/inert nitrogen mixture. Such linearity is examined by experimental data reported in the literature, which include the cases of methane, propane, ethylene and propylene. The R-squared values (R(2)) of the regression lines of the cases explored are all greater than 0.989 for upper flammability limit (UFL). The theoretical slope of the predictive line for lower flammability limit (LFL) is found to be very close to zero for all explored cases; and this result successfully explains the experimental fact that adding inert nitrogen to a flammable material has very limited effect on LFL. Because limit oxygen concentration (LOC) could be taken as the intersectional point of the UFL curve and LFL curve, a LOC-based method is proposed to predict the slope of the UFL curve when experimental data of UFL are not available. This LOC-based method predicts the UFL with average error ranging from 2.17% to 5.84% and maximum error ranging from 8.58% to 12.18% for the cases explored. The predictive models for inert gas of nitrogen are also extended to the case of inert gas other than nitrogen. Through the extended models, it was found that the inert ability of an inert gas depends on its mean molar heat capacity at the adiabatic flame temperature. Theoretical calculation shows that the inert abilities of carbon dioxide, steam, nitrogen and helium are in the following order: carbon dioxide>steam>nitrogen>helium; and this sequence conforms to the existing experimental data reported in the literature.

It was reported previously that hepatitis delta virus (HDV), the only animal virus in which replication is performed by cellular RNA polymerase(s), undergoes RNA recombination. However, the previous RNA transfection system was somewhat limited in terms of practical application. Cultured cells were transfected with plasmids expressing replication-competent genotypes I and IIb HDV genomic RNAs to develop a better system for studying the fundamental aspects of HDV RNA recombination and HDV-related RNA species were examined using restriction fragment length polymorphisms and sequence analysis of cloned RT-PCR products. This novel experimental system generated efficiently recombinants between the two parental HDV sequences, but not between replication-defective HDV constructs. The genome organization of the HDV recombinants produced in this system resembled that observed previously in cultured cells co-transfected with genome I and IIb RNAs. These data indicate that replication-dependent HDV RNA recombination can be catalyzed by host RNA polymerases in cultured cells co-transfected with two cloned HDV sequences. This new DNA-based system is simpler than the previous RNA-based method of study, and generates a higher recombination frequency, facilitating study of HDV RNA recombination.