A quantum-chemical study of conformations and electronic structures of poly(m-phenylene) [PMP] and the related polyphenylenes was performed to elucidate the origin of the broken conjugation found in m-phenylene linked conjugated polymers. Potential energy curves of the polymers as a function of both torsion and helical angles were constructed through semiempirical Hartree−Fock band calculations at the Austin model 1 (AM1) level. It is found that two helical conformations of PMP are possible:  one with a helical angle (α) of 72° and the other with α = 144°. The former is identical with the conformation of an oligomer in the solid state, m-deciphenyl structure. Our calculations predict that both helices are more stable by 2.5 kcal/mol per phenyl ring than the anti-coplanar conformation and that they exhibit absorption peaks at 5.8 eV. The electronic structure of PMP is, however, not affected significantly by increasing the planarity of a PMP chain but affected by copolymerization with other conjugated units. This implies that localization occurs in the m-phenylene ring itself. We examined the electronic structures of PMP and the related copolymers and found that the weak conjugation along the m-phenylene linked conjugated backbone is related to the inherent nodal nature of the frontier molecular orbitals of the unit even in the planar conformation.

Lactic acid bacteria (LAB) are the common probiotics. Here, we investigated the antiviral protective effects of heat-killed LAB strain Lactobacillus casei DK128 (DK128) on influenza viruses. Intranasal treatment of mice with DK128 conferred protection against different subtypes of influenza viruses by lessening weight loss and lowering viral loads. Protection via heat-killed DK128 was correlated with an increase in alveolar macrophage cells in the lungs and airways, early induction of virus specific antibodies, reduced levels of pro-inflammatory cytokines and innate immune cells. Importantly, the mice that were protected against primary viral infection as a result of heat-killed DK128 pretreatment developed subsequent heterosubtypic immunity against secondary virus infection. For protection against influenza virus via heat-killed DK128 pretreatment, B cells and partially CD4 T cells but not CD8 T cells were required as inferred from studies using knockout mouse models. Our study provides insight into how hosts can be equipped with innate and adaptive immunity via heat-killed DK128 treatment to protect against influenza virus, supporting that heat-killed LAB may be developed as anti-virus probiotics.

No abstract

ObjectivesCoblation is operated in low temperature, so it is proposed that tonsillectomy with coblation involves less postoperative pain and allows accelerated healing of the tonsillar fossae compared with other methods involving heat driven processes. However, the results of the previous studies showed that the effect of coblation tonsillectomy has been equivocal in terms of postoperative pain and hemorrhage. Though, most of the previous studies which evaluated coblation tonsillectomy were performed in children. Recently, electrocautery tonsillectomy has been used most widely because of the reduced intraoperative blood loss and shorter operative time compared to other techniques. This prospective study compared intraoperative records and postoperative clinical outcomes in adolescents and adults following coblation and electrocautery tonsillectomies.MethodsEighty patients over 16 years of age with histories of recurrent tonsillitis were enrolled. The patients were randomly allocated into coblation (n=40) and electrocautery tonsillectomy groups (n=40). All operations were performed by one surgeon who was skilled in both surgical techniques. Intraoperative parameters and postoperative outcomes were checked.ResultsPostoperative pain and otalgia were not significantly different between the two groups; however, there was a tendency towards reduced pain and otalgia in the coblation group. More cotton balls for swabbing the operative field were used introoperatively in the electrocautery group (P=0.00). There was no significant difference in postoperative hemorrhage, wound healing, commencement of a regular diet, and foreign body sensation between the groups.ConclusionOnly cotton use, which represented the amount of blood loss, was less in the coblation tonsillectomy group. Coblation tonsillectomy warrants further study with respect to the decreased postoperative pain and otalgia.

In order to more accurately predict band gaps, corresponding to π–π* transitions of one-dimensional conducting polymers, the formula for the off-diagonal elements, Hαβij in the extended Hückel (EH) band calculation method was modified according to the form Hαβij=K1(Hααii +Hββjj)exp(−K2Rαβ) Sαβij. Parametrizations for the constants K1 and K2 were performed so as to yield reasonable band gaps for the pure hydrocarbon polymers trans-polyacetylene, poly(para-phenylene), and poly(phenylene vinylene). Since there is a large difference in bond alternations along polymeric chains between ab initio and modified neglect of diatomic overlap optimized geometries, especially for heterocyclic polymers, the valence orbital exponents of oxygen, nitrogen, and sulfur were separately adjusted, depending on the chosen geometry, to reproduce the band gaps of polyfuran, polypyrrole, and polythiophene. It is found that geometrical relaxations in the presence of heteroatoms strongly affect the C1–C4 interactions as well as bond alternations, which in turn affect the band gap. Modified EH band calculations were performed for various polymers. The predicted band gaps had average errors of ca. 10% (less than 0.3 eV) compared to the experimental values, and the method produced band structures consistent with electron-energy-loss spectroscopic observations.