Stationary distribution of a stochastic Alzheimer's disease model

In this paper, based on the pathogenesis of Alzheimer's disease, we investigate a stochastic mathematical model, focusing on the dynamics of β-amyloid (Aβ) plaques, Aβ oligomers, PrP^C proteins, and the Aβ-x-PrP^C complex. Within the framework of the Lyapunov method, we first show existence and uniqueness of global positive solution of the model and then establish the sufficient conditions for existence of an ergodic stationary distribution of the positive solution. Ultimately, numerical examples are presented to illustrate the effectiveness of theoretical results.     

Composition dependent self‐regenerative property of perovskite‐type oxides

The self‐regenerative property of LaCo_{1–x –y}Pd_x Zn_y O_3±δ and LaFe_{1–x –y}Pd_x Zn_y O_3±δ solid solutions with monometallic Pd or bimetallic Pd/Zn substituents for Co or Fe is studied under a redox cycle by high angular annular dark‐field scanning transmission electron microscopy (STEM‐HAADF) and energy dispersive X‐ray spectroscopy (EDX) and X‐ray diffraction (XRD). These results reveal that the composition of perovskites determines the self‐regenerative property that occurs largely in LaCo_{1–x –y}Pd_x Zn_y O_3±δ but is limited greatly in LaFe_{1–x –y}Pd_x Zn_y O_3±δ. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)     

Overcoming the Unexpected Functional Inversion of a PqsR Antagonist in Pseudomonas aeruginosa: An In Vivo Potent Antivirulence Agent Targeting pqs Quorum Sensing

The virulence regulator PqsR of Pseudomonas aeruginosa is considered as an attractive target for attenuating the bacterial pathogenicity without eliciting resistance. However, despite efforts and desires, no promising PqsR antagonist has been discovered thus far. Now, a surprising functionality change of a highly affine PqsR antagonist in P. aeruginosa is revealed, which is mediated by a bacterial signal molecule synthase and responsible for low cellular potency. Blockade of the susceptible position led to the discovery of the first antivirulence compound that is potent in vivo and targets PqsR, thus providing a proof of concept for this novel antivirulence therapy.     

Base‐Controlled Selectivity in the Synthesis of Linear and Angular Fused Quinazolinones by a Palladium‐Catalyzed Carbonylation/Nucleophilic Aromatic Substitution Sequence

A new approach for the facile synthesis of fused quinazolinone scaffolds through a palladium‐catalyzed carbonylative coupling followed by an intramolecular nucleophilic aromatic substitution is described. The base serves as the key modulator: Whereas DBU gives rise to the linear isomers, Et₃N promotes the preferential formation of angular products. Interestingly, a light‐induced 4+4 reaction of the product was also observed.     

Reactions of rac‐(ebthi)M(η2‐Me3SiC2SiMe3) (M=Ti,Zr) with Aryl Nitriles

The reactions of the Group 4 metallocene alkyne complexes rac‐(ebthi)M(η²‐Me₃SiC₂SiMe₃) ( 1 a : M=Ti, 1 b : M=Zr; rac‐(ebthi)=rac‐1,2‐ethylene‐1,1′‐bis(η⁵‐tetrahydroindenyl)) with Ph?C?N were investigated. For 1 a , an unusual nitrile–nitrile coupling to 1‐titana‐2,5‐diazacyclopenta‐2,4‐diene ( 2 ) at ambient temperature was observed. At higher temperature, the C?C coupling of two nitriles resulted in the formation of a dinuclear complex with a four‐membered diimine bridge ( 3 ). The reaction of 1 b with Ph?C?N afforded dinuclear compound 4 and 2,4,6‐triphenyltriazine. Additionally, the reactivity of 1 b towards other nitriles was investigated.     

Bis(N-Heterocyclic Carbene) Manganese(I) Complexes: Efficient and Simple Hydrogenation Catalysts

The use of bis(NHC) manganese(I) complexes 3 as catalysts for the hydrogenation of esters was investigated. For that purpose, a series of complexes has been synthesized via an improved two step procedure utilizing bis(NHC)-BEt₃ adducts. By applying complexes 3 with KHBEt₃ as additive, various aromatic and aliphatic esters were hydrogenated successfully at mild temperatures and low catalyst loadings, highlighting the efficiency of the novel catalytic system. The versatility of the developed catalytic system was further demonstrated by the hydrogenation of other substrate classes like ketones, nitriles, N-heteroarenes and alkenes. Mechanistic experiments and DFT calculations indicate an inner sphere mechanism with the loss of one CO ligand and reveal the role of BEt₃ as cocatalyst.     

Diffusion-weighted MRI for the detection of colorectal polyps: feasibility study

The purpose of this study was to determine the feasibility of diffusion-weighted magnetic resonance imaging (DWI) for detecting colorectal polyps. DWI (high b-value of 1000 s/mm²) was prospectively performed in 26 symptomatic patients who were scheduled to undergo colonoscopy. DWI and colonoscopic findings were interpreted in a blinded manner. The sensitivity and positive predictive value (PPV) of DWI for the detection of clinically relevant polyps (≥ 6 mm) and colorectal cancer (CRC) were calculated on a per-lesion basis, using colonoscopy results as the standard of reference. Sensitivity, specificity, PPV and negative predictive value (NPV) on a per-patient basis were also calculated. Sensitivity and PPV on a per-lesion basis were 80.0% [95% confidence interval (CI): 49.0%–94.3%] and 72.7% (95% CI: 43.4%–90.3%) for polyps ≥ 6 mm and CRC. Sensitivity, specificity, PPV and NPV on a per-patient basis were 85.7% (95% CI: 48.7%–97.4%), 84.2% (95% CI: 62.4%–94.5%), 66.7% (95% CI: 35.4%–87.9%) and 94.1% (95% CI: 73.0%–99.0%) for polyps ≥ 6mm and CRC. In conclusion, DWI cannot yet be recommended in a clinical setting in which DWI is performed first and subsequent colonoscopy is only performed in patients with positive findings at DWI. Further (technical) developments are required to increase its diagnostic yield.