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Phase transitions of 1-fluoro-adamantane have been thoroughly investigated by temperature-resolved second harmonic generation (TR-SHG) and X-ray powder diffraction (XRPD). A new polymorph--an intermediate centrosymmetric phase (MT)--between the known orientationally disordered high temperature phase (HT, Fm3m, Z = 4) and the low temperature phase (LT, P421c, Z = 2) was unveiled by TR-SHG. The crystal structure of MT was resolved by XRPD in the P42/nmc (Z = 2) space group, and it is related to the LT phase in a group-subgroup relation. No evidence of any solid-solid transition between these two phases by differential scanning calorimetry (DSC) or cold-stage microscopy could be obtained. Therefore, combing TR-SHG, XRPD, DSC, and cold-stage microscopy results, a second-order transition mechanism is proposed for the MT ↔ LT transition. Moreover, the critical exponent (β) of the order parameter was calculated by fitting TR-SHG data to a critical power law. The obtained β value (0.26) is close to the value from XRPD data (0.25). [ABSTRACT FROM AUTHOR]

Background: Next-generation sequencing (NGS) technologies have greatly promoted the genomic study of prokaryotes. However, highly fragmented assemblies due to short reads from NGS are still a limiting factor in gaining insights into the genome biology. Reference-assisted tools are promising in genome assembly, but tend to result in false assembly when the assigned reference has extensive rearrangements. Results: Herein, we present GAAP, a genome assembly pipeline for scaffolding based on core-gene-defined Genome Organizational Framework (cGOF) described in our previous study. Instead of assigning references, we use the multiple-reference-derived cGOFs as indexes to assist in order and orientation of the scaffolds and build a skeleton structure, and then use read pairs to extend scaffolds, called local scaffolding, and distinguish between true and chimeric adjacencies in the scaffolds. In our performance tests using both empirical and simulated data of 15 genomes in six species with diverse genome size, complexity, and all three categories of cGOFs, GAAP outcompetes or achieves comparable results when compared to three other reference-assisted programs, AlignGraph, Ragout and MeDuSa. Conclusions: GAAP uses both cGOF and pair-end reads to create assemblies in genomic scale, and performs better than the currently available reference-assisted assembly tools as it recovers more assemblies and makes fewer false locations, especially for species with extensive rearranged genomes. Our method is a promising solution for reconstruction of genome sequence from short reads of NGS. [ABSTRACT FROM AUTHOR]

The electron self-exchange rate constants for the (trimethylammonio)methylferrocene(/2) couple (FcTMA2) have been measured in the absence and presence of the cucurbit7uril (CB7) host molecule in aqueous solution, using 1H NMR line-broadening experiments. The very strong binding of the ferrocene to CB7 results in slow exchange of the guest on the NMR time scale, such that resonances for both the free and bound forms of the reduced ferrocene can be observed. The extents of line broadening in the resonances of the two forms of the guest in the presence of the FcTMA2species can be monitored independently, allowing for the determination of the rate constants for the possible self-exchange pathways involving the bound and free forms of both the oxidized and reduced members of the redox couple. The encapsulation of both the reduced and oxidized forms of the ferrocene increases the rate constant (25 °C) from (2.1 ± 0.1) × 106M-1s-1(for FcTMA2) to (6.7 ± 0.7) × 106M-1s-1(for FcTMA·CB72), whereas inclusion of the reduced form only decreases the rate constant to (6 ± 1) × 105M-1s-1. The changes in the exchange rate constants upon inclusion of the reactants are related to the effects of CB7 acting as an outer, second-coordination sphere and are compared to those observed previously for the electron-exchange process in the presence of -cyclodextrin and p-sulfonated calix6arene hosts. The binding of FcTMAand hydroxymethylferrocene to CB7 significantly reduces the rate constants for their oxidations by the bis(2,6-pyridinedicarboxylato)cobaltate(III) ion (which does not bind to CB7) as a result of reduced thermodynamic driving forces and steric hindrance to close approach of the oxidant to the encapsulated ferrocenes. [ABSTRACT FROM AUTHOR]

Telah dilakukan penelitian tentang pemisahan tembaga dari mineral bornit terhadap pengaruh rapat arus dan pengompleks EDTA secara elektrolisis. Serbuk bornit dilarutkan dalam besi(III) sulfat dan diendapkan dengan variasi rapat arus menggunakan elektrode karbon selama 1 jam.Dari hasil penelitian diperoleh kadar tembaga maksimal yang terlarut sebesar 14,88 % pada konsentrasi besi(III) sulfat 0,6 M. Semakin besar rapat arus yang digunakan pada elektrolisis, kuantitas endapan semakin meningkat dan endapan tembaga maksimal 1,69 mg terbentuk pada penambahan pengompleks EDTA 0,20 M dan rapat arus 0,05 A/cm2. Keberadaan pengompleks EDTA mampu menurunkan potensial yang diperlukan sehingga meningkatkan kemurnian dan kekuatan pelapisan tembaga. Kemurnian endapan tembaga tertinggi didapatkan pada elektrolisis dengan penambahan pengompleks EDTA 0,20 M sebesar 93,88% Kata kunci:bornit, tembaga, rapat arus, pengompleks EDTA