Interaction of poly(styrene sulfonate) with polycations carrying charges in the chain backbone

The interaction between sodium poly(styrene sulfonate) (NaSS) and side-chain charged polycation polymer (pendent type) or main-chain charged polycation polymer (integral type) has been studied. It was found that the polyion complex (the reaction product of these polyelectrolytes) of pendent–pendent type has an equimolar composition at any mixing ratio of two component polymers. However, a polyion complex of integral–pendent type can form a water-soluble complex with a ratio of [polycation]/[polyanion] = 1/3, in addition to a complex with a equimolar composition. The mechanism of formation of this specific complex is discussed.     

N-Phenethylhexadecanamide from the edible mushroom Laetiporus sulphureus

N-Phenethylhexadecanamide was isolated from the MeOH extract of the fruiting bodies of the mushroom Laetiporus sulphureus together with eburicoic acid. Their structures were elucidated by spectroscopic methods.     

Fascicularones H–K,Four New Sesquiterpenoids from the Cultured Mycelia of the Fungus Hypholoma fasciculare

The AcOEt extract of Hypholoma fasciculare yielded four new congeners, fascicularones H ( 4 ), I ( 5 ), J ( 6 ), and K ( 7 ). All structures were unambiguously established by 1D and 2D NMR and MS data. In a lettuce seedling assay, compounds 4 – 7 showed radicle elongation.     

SUPER TOUGH GELS WITH A DOUBLE NETWORK STRUCTURE

Living tissues work with fantastic functions in soft and wet gel-like state.Thus,hydrogels have attracted much attention as excellent soft and wet materials,suitable tot making artificial organs for medical treatments.However, conventional hydrogels are mechanically too weak for practical uses.We have created double network (DN) hydrogels with extremely high mechanical strength in order to overcome this problem.DN gels are interpenetrating network (IPN) hydrogels consisting of rigid polyelectrolyte and s...     

Biosynthesis and characterization of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer from wild-type Comamonas sp. EB172

Poly(3-hydroxybutyrate) [P(3HB)] homopolymer and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] copolymer was produced by Comamonas sp. EB172 using single and mixture of carbon sources. Poly(3-hydroxyvalerate) P(3HV) incorporation in the copolymer was obtained when propionic and valeric acid was used as precursors. Incorporation of 3HV fractions in the copolymer varied from 45 to 86 mol% when initial pH of the medium was regulated. In fed-batch cultivation, organic acids derived from anaerobically treated palm oil mill effluent (POME) were shown to be suitable carbon sources for polyhydroxyalkanoate (PHA) production by Comamonas sp. EB172. Number average molecular weight (M_n) produced by the strain was in the range of 153-412 kDa with polydispersity index (M_w/M_n) in the range of 2.2-2.6, respectively. Incorporation of higher 3HV units improved the thermal stability of P(3HB-co-3HV) copolymer. Thus the newly isolated bacterium Comamonas sp. EB172 is a suitable candidate for PHA production using POME as renewable and alternative cheap raw materials.     

Theoretical study of the mechanism of valence tautomerism in cobalt complexes

Valence tautomerism is studied in the [Co(II-HS)(sq)(2)(bpy)]/[Co(III-LS)(sq)(cat)(bpy)] mononuclear cobalt complex by using DFT methods (HS, high spin; LS, low spin; cat, catecholate; sq, semiquinone; bpy, 2,2'-bipyridine). Calculations at the B3LYP* level of theory reproduce well the energy gap between the Co(II-HS) and Co(III-LS) forms giving an energy gap of 4.4 kcal/mol, which is comparable to the experimental value of 8.9 kcal/mol. Potential energy surfaces and crossing seams of the electronic states of the doublet, quartet, and sextet spin states are calculated along minimum energy paths connecting the energy minima corresponding to the different spin states. The calculated minimum energy crossing points (MECPs) are located at 8.8 kcal/mol in the doublet/sextet surfaces, at 10.2 kcal/mol in the doublet/quartet surfaces, and at 8.4 kcal/mol in the quartet/sextet surfaces relative to the doublet ground state. Considering the energy of the three spin states and the crossing points, the one-step relaxation mechanism between the Co(II-HS) and Co(III-LS) forms is the most probable. This research shows that mapping MECPs can be a useful strategy to analyze the potential energy surfaces of systems with complex deformation modes.     

水溶性导电高分子聚噻吩及其水凝胶的掺杂行为研究

用碘和高氯酸作掺杂剂对水溶性导电高分子聚（3-羧甲基噻吩）及其水凝胶的掺杂行为进行了系统研究。结果发现水溶胀聚（3-羧甲基噻吩）凝胶及其高分子很容易被高氯酸或碘的水溶液进行掺杂，且其掺杂能力强烈依赖于掺杂剂溶液浓度。对碘掺杂的高分子溶液，其掺杂过程不很稳定同时伴随着脱掺杂过程的发生，而对于聚噻吩凝胶，高氯酸极易使其掺杂，而且一旦掺杂则在掺杂状态下具有相对的稳定性。     

On a property specific to the tent map

Let a set {X_λ; λ  Λ} of subspaces of a topological space X be a cover of X. Mathematical conditions are proposed for each subspace X_λ to define a map g_Xλ:X_λ→X which has the following property specific to the tent map known in the baker’s transformation. Namely, for any infinite sequence ω₀, ω₁, ω₂, … of X_λ, λ  Λ, we can find an initial point x₀  ω₀ such that g_ω0(x₀)ω₁,g_ω1(g_ω0(x₀))ω₂,…. The conditions are successfully applied to a closed cover of a weak self-similar set.