Estimation method for parameters of construction on predicting transmission loss of double leaf dry partition

For improving sound insulation of a double leaf dry partition, each leaf is often consisted of more than one panel. Previous study on predicting a transmission loss of double leaf partition, treats with the leaf varied just two kinds of panels and restricted to a leaf having same kind and same thickness. These restrictions are unfit for variety of current building materials and constructions. This study makes a prediction formula for a transmission loss of the double leaf partition with laminated leaves by a theoretical analysis and an experiment, and will discuss the predicted value with measured value in previous studies and catalogs.     

Further Stabilization of Leu<Superscript>155</Superscript> Mutant Thermolysins by Mutation of an Autodegradation Site

The autodegradation-resistant mutant thermolysins (TLNs), L155A (Leu¹⁵⁵ to Ala) and L155S (Leu¹⁵⁵ to Ser), were previously constructed by site-directed mutagenesis to enhance thermostability. These mutations suppressed autodegradation at position 154–155, resulting in increased thermostability. However, a new autodegradation site became apparent in these mutant TLNs, at position 155–156. In this study, further stabilization of the mutant TLNs to suppress this new autodegradation was attempted by the substitution of Ile¹⁵⁶ to Asp and Val (L155A-I156N, L155A-I156V, L155S-I156N, and L155S-I156V). SDS–PAGE analysis showed that the autodegradation at 155–156 of all double-mutant TLNs was suppressed. Thermostability at 80 °C was enhanced in all double-mutant TLNs (half-life at 80 °C: WT, 18.3 min; L155A, 25.0 min; L155S, 24.0 min; L155A-I156N, 60.8 min; L155A-I156V, 62.4 min; L155S-I156N, 93.3 min; and L155S-I156V, 40.0 min), and k _cat/K _m values were: WT, 220; L155A, 240; L155S, 123; L155A-I156N, 62; L155A-I156V, 760; L155S-I156N, 240; and L155S-I156V, 520 min⁻¹ mM⁻¹.     

Synthesis and Reactivity of 5,10,15‐Triaryl Doubly N‐Confused Bilanes

A series of 5,10,15‐tris(pentafluorophenyl) doubly N‐confused bilanes were synthesized in a stepwise manner with the aid of sterically demanding N‐protecting groups, in which the difference in reactivity between regular pyrrole and N‐confused pyrrole plays a crucial role in the synthetic strategy. Some doubly N‐confused bilanes were converted into porphyrinoids or a unique 2:2 copper(II) complex with a helical structure. In addition, the conformations and electronic states of the doubly N‐confused bilanes were investigated theoretically, giving fruitful information about the effect of confusion on the bilane skeleton.     

Regulation of NH-tautomerism in N-confused porphyrin by N-alkylation

A variety of internally N-alkylated N-confused porphyrins were prepared in a stepwise manner through the protection of the reactive peripheral nitrogen atom. NH-Tautomerism in N-confused porphyrins was found to be regulated by N-alkylation, which enabled us to obtain discrete information on two important NH-tautomers of an N-confused porphyrin.     

Short polyglutamine peptide forms a high-affinity binding site for thioflavin-T at the N-terminus

Thioflavin-T is one of the most important amyloid specific dyes and has been used for more than 50 years; however, the molecular mechanism of staining is still not understood. Chemically synthesized short polyglutamine peptides (Q(n), n = 5-10) were subjected to the thioflavin-T (ThT) staining assay. It was found that the minimum Q(n) peptide that stained positive to ThT was Q(6). Two types of ThT-binding sites, a high-affinity site (k(d1) = 0.1-0.17 μM) and a low-affinity site (k(d2) = 5.7-7.4 μM), were observed in short polyQs (n = 6-9). (13)C{(2)H}REDOR NMR experiments were carried out to extract the local structure of ThT binding sites in Q(8) peptide aggregates by observing the intermolecular dipolar coupling between [3-Me-d(3)]ThT and natural abundance Q(8) or residue-specific [1,2-(13)C(2)] labeled Q(8)s. (13)C{(2)H}REDOR difference spectra of the [3-Me-d(3)]ThT/natural abundance Q(8) (1/9) complex indicated that all of the five carbons of the glutamine residue participated in the formation of ThT-binding sites. (13)C{(2)H}DQF-REDOR experiments of [3-Me-d(3)]ThT/residue-specific [1,2-(13)C(2)] labeled Q(8) (1/50) complexes demonstrated that the N-terminal glutamine residue had direct contact with the ThT molecule at the high-affinity ThT-binding sites.     

Relative Configuration of JBIR-129, a Cytotoxic 34-Membered Glycosidic Polyol Macrolide from Streptomyces sp. RK74

JBIR-129 was isolated as the potent cytotoxic compound, which consists of the 34-membered polyol macrolide skeleton with five sugar moieties. The relative configuration of the aglycone moiety (C7-C27 and C33-C39) was established by the J-based configuration analysis using vicinal (1)H-(1)H (from (1)H NMR and PS-DQF-COSY spectra) and long-range (1)H-(13)C coupling constants (from sge-HETLOC and several J-resolved HMBC spectra) with steric information obtained from ROESY.     

Structures of beta-FeOOH particles formed in the presence of Ti(IV), Cr(III), and Cu(II) ions

beta-FeOOH particles were prepared by aging aqueous FeCl3 solutions containing Ti(IV), Cr(III), and Cu(II) at room temperature for 360 days. The structures of the formed particles were investigated by various techniques including TEM, XRD, XAFS, and adsorption of N2 and H2O. Ti(IV) markedly impeded the crystallization and particle growth of beta-FeOOH by coprecipitation with Fe(III) and disturbing the short-range structure of beta-FeOOH particles. In the presence of a large amount of Ti(IV), it was pronounced that the hydrolysis of Ti(IV) impeded beta-FeOOH formation by reducing the solution pH, whereas Cr(III) and Cu(II), which were hardly involved in the products, gave rise to no noticeable effects on the formation of beta-FeOOH particles. The knowledge obtained in this study can be available for interpretation of the anti-corroding function of Ti alloyed with steels in a Cl- -containing environment.     

Influence of hydrolyzed and nonhydrolyzed Ti,Cr, and Al ions on the formation of beta-FeOOH particles

Beta-FeOOH particles were synthesized in the presence of Ti(IV), Al(III), and Cr(III) at metal/Fe atomic ratios of 0-0.1 by the following two methods: hydrolysis of aqueous FeCl3 solutions added to the hydrolysis products of these metal ions (subsequent hydrolysis, SH) and hydrolysis of aqueous FeCl3 solutions dissolving these metal ions (combined hydrolysis, CH). On increasing Al/Fe the particle size of the products with AlCl3 by SH method steeply rose at a low Al/Fe and then fell. The similar increase of particle size was seen in SH method with Ti(SO4)2 though the addition of TiCl4 decreased the particle size. In CH method, Ti(IV) markedly impeded the beta-FeOOH formation but Al(III) and Cr(III) showed no influence. The particles prepared by CH and SH methods contained a large amount of Ti(IV) but a few Al(III) and Cr(III). The large spindle-shaped and rod-shaped particles produced by SH method with AlCl3 and Ti(SO4)2 were highly microporous and poorly crystallized, indicating that the particles consist of fine primary particles and the aggregation of fine particles would be promoted by SO4(2-). The different influences of the metal ions on the beta-FeOOH formation were explained by their hydrolysis characteristics.