Peierls Instabilities in Quasi-One-Dimensional Quantum Double-Well Chains

Peierls-type instabilities in quarter-filled ($\bar{n}=1/2$) and half-filled ($\bar{n}=1$) quantum double-well hydrogen-bonded chain are investigated analytically in the framework of two-stage orientational-tunnelling model with additional inclusion of the interactions of protons with two different optical phonon branches. It is shown that when the energy of proton-phonon coupling becomes large, the system undergoes a transition to a various types of insulator states. The influence of two different transport amplitudes on ground states properties is studied. The results are compared with the pressure effect experimental investigations in superprotonic systems and hydrogen halides at low temperatures.Comment: 7 pages, RevTeX, 9 eps figure

Morphologically disordered pore model for characterization of micro-mesoporous carbons

We present a new morphologically disordered slit-shaped pore (MDSP) model for simulating gas adsorption in micro-mesoporous carbonaceous materials. The MDSP model qualitatively accounts for the inherent roughness of carbon pore walls in accord with the atomistic structural model of LMA10 reference carbon material. The MDSP model is applied to pore size distribution (PSD) calculations from nitrogen adsorption isotherms measured at 77.4 K in the range of pore widths from 0.72 to 40 nm. The MDSP model improves significantly the nitrogen adsorption porosimetry and, being fully atomistic, it is transferable to study various adsorbate-adsorbent systems. Computations of PSD functions for a series of carbonaceous materials, including activated carbon fiber, granular activated carbons, synthetic activated carbons showed that MDSP generates smooth Gaussian-type PSD functions with a well-defined average pore size. Furthermore, PSD functions computed from the MDSP model are free from the artificial gaps in the region of narrow micropores (∼1 nm and ∼2 nm) predicted from the standard slit-shaped pore models with ideal graphite-like walls. MDSP is not only a complementary model to existing approaches, such as quench-solid density functional theory method, but it paves the way to efficient atomistic simulations of various compounds within morphologically disordered carbon nanopores

Comparison between clinical significance of serum proinflammatory proteins (IL-6 and CRP) and classic tumor markers (CEA and CA 19-9) in gastric cancer

Gastric cancer (GC) is a second most common cause of cancer-related death and represents an inflammation-driven malignancy. It has been suggested that interleukin 6 (IL-6) and C-reactive protein (CRP) play a potential role in the growth and progression of GC. The aim of the present study was to compare clinical significance of IL-6 and CRP with classic tumor markers—carcinoembryonic antigen (CEA) and carbohydrate antigen (CA 19-9) in GC patients. The study included 92 patients with GC and 70 healthy subjects. The serum concentrations of IL-6, CEA and CA 19-9 were determined using immunoenzyme assays, whereas CRP using immunoturbidimetric method. We defined the diagnostic criteria and prognostic value for proteins tested. In GC patients, the serum concentrations of all the proteins tested were significantly higher than in healthy subjects. The IL-6, CEA and CA 19-9 levels correlated with nodal metastases, while CRP with tumor stage, gastric wall invasion, presence of nodal and distant metastases. Diagnostic sensitivity of IL-6 was higher (85%) than those of other markers (CRP 66%, CA 19-9 34%, CEA 22%) and increased in combined use with CRP or CEA (88%). The area under ROC curve for IL-6 was larger than those of CRP and classic tumor markers (CEA and CA 19-9). None of the proteins tested was independent prognostic factor for the survival of GC patients. Our findings indicate better usefulness of serum proinflammatory proteins—IL-6 and CRP than classic tumor markers—CEA and CA 19-9 in the diagnosis of GC

A synthesis of bacterial and archaeal phenotypic trait data

A synthesis of phenotypic and quantitative genomic traits is provided for bacteria and archaea, in the form of a scripted, reproducible workflow that standardizes and merges 26 sources. The resulting unified dataset covers 14 phenotypic traits, 5 quantitative genomic traits, and 4 environmental characteristics for approximately 170,000 strain-level and 15,000 species-aggregated records. It spans all habitats including soils, marine and fresh waters and sediments, host-associated and thermal. Trait data can find use in clarifying major dimensions of ecological strategy variation across species. They can also be used in conjunction with species and abundance sampling to characterize trait mixtures in communities and responses of traits along environmental gradients

Capric Acid Secreted by S. boulardii Inhibits C. albicans Filamentous Growth, Adhesion and Biofilm Formation

Candidiasis are life-threatening systemic fungal diseases, especially of gastro intestinal track, skin and mucous membranes lining various body cavities like the nostrils, the mouth, the lips, the eyelids, the ears or the genital area. Due to increasing resistance of candidiasis to existing drugs, it is very important to look for new strategies helping the treatment of such fungal diseases. One promising strategy is the use of the probiotic microorganisms, which when administered in adequate amounts confer a health benefit. Such a probiotic microorganism is yeast Saccharomyces boulardii, a close relative of baker yeast. Saccharomyces boulardii cells and their extract affect the virulence factors of the important human fungal pathogen C. albicans, its hyphae formation, adhesion and biofilm development. Extract prepared from S. boulardii culture filtrate was fractionated and GC-MS analysis showed that the active fraction contained, apart from 2-phenylethanol, caproic, caprylic and capric acid whose presence was confirmed by ESI-MS analysis. Biological activity was tested on C. albicans using extract and pure identified compounds. Our study demonstrated that this probiotic yeast secretes into the medium active compounds reducing candidal virulence factors. The chief compound inhibiting filamentous C. albicans growth comparably to S. boulardii extract was capric acid, which is thus responsible for inhibition of hyphae formation. It also reduced candidal adhesion and biofilm formation, though three times less than the extract, which thus contains other factors suppressing C. albicans adherence. The expression profile of selected genes associated with C. albicans virulence by real-time PCR showed a reduced expression of HWP1, INO1 and CSH1 genes in C. albicans cells treated with capric acid and S. boulardii extract. Hence capric acid secreted by S. boulardii is responsible for inhibition of C. albicans filamentation and partially also adhesion and biofilm formation