On source-type solutions and the Cauchy problem for a doubly degenerate sixth-order thin film equation, I: Local oscillatory properties

As a key example, the sixth-order doubly degenerate parabolic equation from thin film theory,

     

The karyotype and sex chromosomes of Praomys tullbergi (Muridae, Rodentia): a detailed characterization

Here we present the first detailed characterization of Praomys tullbergi karyotype, enlightening several chromosome features such as constitutive heterochromatin, telomeric and LINE-1 sequences. The combination of these approaches provided some interesting insights about the genome organization of this African species, which is one of the tullbergi complex elements, a group of species belonging to Murinae (Rodentia, Muridae). Evolutionary considerations on Praomys chromosomes were also achieved, namely, the autosomal complement and the X chromosome from P. tullbergi seem to be derivative chromosomes, most probably resulting from extensive reshufflings during the course of evolution. This conclusion came from the fact that the majority of the chromosomes telomeric sequences are located interstitially, seeming footprints of evolutionary chromosome rearrangements. The detailed analysis of Praomys tullbergi X chromosome suggests that chromosome rearrangements and/or centromere transpositions and addition/elimination of heterochromatin must have been the main evolutionary events that shaped this chromosome.     

Generalized Lyddane-Sachs-Teller relation

A generalized Lyddane-Sachs-Teller relation is derived. The assumption that the ionic motion is described by a set of independent damped oscillators is relaxed, and the derivation is based simply on causality and energy conservation, plus the assumption that ? has a finite number of poles and zeroes. The parameters appearing in the factorization have a somewhat different meaning from that previously accepted, but they are more directly related to the observable quantities in neutron and Raman scattering, and infrared experiments.     

Oxidation of thiolesters : Some aspects of the chemistry of s-acylthiol s-oxides and related compounds

In the ozone oxidation of thiolesters in 1,2-dichloroethane at room temperature, S-acylthiol S-oxides 3 are proposed as intermediates. The isolation of carboxylic acid anhydrides and dialkyl disulphides as the actual reaction products can be explained as resulting from the decomposition of the unstable. S-acyl S-acyloxysul-phonium salt 4 arising probably from the reaction of the intermediate S-acylthiol S-oxides with another mole of thiolester. However, in the case of hindered thiolesters, the S-acylthiol S-oxides formed rearrange, possibly via an S→ O acyl shift, to the corresponding acyl sulphenates 12 which on further oxidation lead to the mixed carboxylic acid sulphonic acid anhydrides 13.     

Novel Donepezil–Arylsulfonamide Hybrids as Multitarget-Directed Ligands for Potential Treatment of Alzheimer’s Disease

Alzheimer’s disease (AD) is one of the most devastating neurodegenerative disorders, characterized by multiple pathological features. Therefore, multi-target drug discovery has been one of the most active fields searching for new effective anti-AD therapies. Herein, a series of hybrid compounds are reported which were designed and developed by combining an aryl-sulfonamide function with a benzyl-piperidine moiety, the pharmacophore of donepezil (a current anti-AD acetylcholinesterase AChE inhibitor drug) or its benzyl-piperazine analogue. The in vitro results indicate that some of these hybrids achieve optimized activity towards two main AD targets, by displaying excellent AChE inhibitory potencies, as well as the capability to prevent amyloid-β (Aβ) aggregation. Some of these hybrids also prevented Aβ-induced cell toxicity. Significantly, drug-like properties were predicted, including for blood-brain permeability. Compound 9 emerged as a promising multi-target lead compound (AChE inhibition (IC₅₀ 1.6 μM); Aβ aggregation inhibition 60.7%). Overall, this family of hybrids is worthy of further exploration, due to the wide biological activity of sulfonamides.     

Development of a versatile rotating ring-disc electrode for in situ pH measurements

There are some electrocatalytic reactions in which the key parameter explaining their behavior is a local change in pH. Therefore, it is of utter importance to develop an electrode that could quantify this parameter in situ, but also be customizable to be used in different systems. The purpose of this work is to build a versatile rotating ring/disc electrode (RRDE) with IrO_x deposited on a glass tube as a ring and any kind of material as disc. As the IrO_x is sensitive to pH variation, the reactions promoted on the disc can trigger proportional pH shifts on the ring. In such assembly, the IrO_x ring presents a fast response time even during the pH transients due to the small thickness of the ring (approximately 10 μm), which enables the detection of interfacial pH changes. The ring electrode was tested toward the interfacial pH shift observed during the electrolytic reduction of water on the disc and also characterized by acid–base titration to determine the response time. As the main conclusions, fast response and durable RRDE were obtained, and this assembly could be used to revisit many electrocatalytic reactions in order to test the importance of local pH on the process.     

Spontaneous CO Release from RuII(CO)2–Protein Complexes in Aqueous Solution,Cells, and Mice

We demonstrate that Ru^II(CO)₂–protein complexes, formed by the reaction of the hydrolytic decomposition products of [fac‐RuCl(κ²‐H₂NCH₂CO₂)(CO)₃] (CORM‐3) with histidine residues exposed on the surface of proteins, spontaneously release CO in aqueous solution, cells, and mice. CO release was detected by mass spectrometry (MS) and confocal microscopy using a CO‐responsive turn‐on fluorescent probe. These findings support our hypothesis that plasma proteins act as CO carriers after in vivo administration of CORM‐3. CO released from a synthetic bovine serum albumin (BSA)–Ru^II(CO)₂ complex leads to downregulation of the cytokines interleukin (IL)‐6, IL‐10, and tumor necrosis factor (TNF)‐α in cancer cells. Finally, administration of BSA–Ru^II(CO)₂ in mice bearing a colon carcinoma tumor results in enhanced CO accumulation at the tumor. Our data suggest the use of Ru^II(CO)₂–protein complexes as viable alternatives for the safe and spatially controlled delivery of therapeutic CO in vivo.     

Electron pairing and chemical bonds: pair localization in ELF domains from the analysis of domain averaged Fermi holes

This article reports the application of a recently proposed formalism of domain averaged Fermi holes to the problem of the localization of electron pairs in electron localization function (ELF) domains and its possible implications for the electron pair model of chemical bond. The main focus was on the systems, such as H2O or N2, in which the "unphysical" population of ELF domains makes the parallel between these domains and chemical bond questionable. On the basis of the results of the Fermi-hole analysis, we propose that the above problems could be due to the fact that in some cases the boundaries of the ELF domains need not be determined precisely enough.     

LC-HRMS/MS-Based Metabolomics Approaches Applied to the Detection of Antifungal Compounds and a Metabolic Dynamic Assessment of Orchidaceae

The liquid chromatography–mass spectrometry (LC-MS)-based metabolomics approach is a powerful technology for discovering novel biologically active molecules. In this study, we investigated the metabolic profiling of Orchidaceae species using LC-HRMS/MS data combined with chemometric methods and dereplication tools to discover antifungal compounds. We analyze twenty ethanolic plant extracts from Vanda and Cattleya (Orchidaceae) genera. Molecular networking and chemometric methods were used to discriminate ions that differentiate healthy and fungal-infected plant samples. Fifty-three metabolites were rapidly annotated through spectral library matching and in silico fragmentation tools. The metabolomic profiling showed a large production of polyphenols, including flavonoids, phenolic acids, chromones, stilbenoids, and tannins, which varied in relative abundance across species. Considering the presence and abundance of metabolites in both groups of samples, we can infer that these constituents are associated with biochemical responses to microbial attacks. In addition, we evaluated the metabolic dynamic through the synthesis of stilbenoids in fungal-infected plants. The tricin derivative flavonoid- and the loliolide terpenoidfound only in healthy plant samples, are promising antifungal metabolites. LC-HRMS/MS, combined with state-of-the-art tools, proved to be a rapid and reliable technique for fingerprinting medicinal plants and discovering new hits and leads.