Singly generated quasivarieties and residuated structures

A quasivariety K of algebras has the joint embedding property (JEP) iff it is generated by a single algebra A. It is structurally complete iff the free countably generated algebra in K can serve as A. A consequence of this demand, called "passive structural completeness" (PSC), is that the nontrivial members of K all satisfy the same existential positive sentences. We prove that if K is PSC then it still has the JEP, and if it has the JEP and its nontrivial members lack trivial subalgebras, then its relatively simple members all belong to the universal class generated by one of them. Under these conditions, if K is relatively semisimple then it is generated by one K-simple algebra. It is a minimal quasivariety if, moreover, it is PSC but fails to unify some finite set of equations. We also prove that a quasivariety of finite type, with a finite nontrivial member, is PSC iff its nontrivial members have a common retract. The theory is then applied to the variety of De Morgan monoids, where we isolate the sub(quasi)varieties that are PSC and those that have the JEP, while throwing fresh light on those that are structurally complete. The results illuminate the extension lattices of intuitionistic and relevance logics

Deciding logics of linear Kripke frames with scattered end pieces

We show that logics based on linear Kripke frames – with or without constant domains – that have a scattered end piece are not recursively enumerable.This is done by reduction to validity in all finite classical models

Polynomial interpolation for inversion-based control

To help to achieve high performances in the regulation of linear scalar (SISO) nonminimum-phase systems, an inversion-based (feedforward) control method is proposed. The aim is designing an inverse input to smoothly switch from a current, arbitrary, steady-state regime to a new, future, desired steady-state output. A new-found polynomial basis solves the related interpolation problem to join the current output to the future one while ensuring the necessary or desired smoothness. The (interpolation) transition time can be minimized in order to optimally reduce the delay with which the desired output occurs. By applying a behavioral stable inversion formula to the overall smoothed output, detailed expressions of the inverse input are finally derived. A simulation of a flexible arm rotating in the horizontal plane exemplifies the presented method

Acrylic-melamine latex with controlled crosslinking capability

Crosslinkable polymers are highly demanded in applications where improved thermal, mechanical, and chemical strengths are required. Among crosslinkable polymers, those with film forming capability are of high technological interest, as in coatings and adhesives. In a scenario of increasing concern for sustainability and stricter environmental legislation, coatings industry has switched to water based products, like acrylic latexes. Crosslinkable latexes aim to improve the physical properties of coalesced latex films, over the levels attainable with thermoplastic latexes, which lack hardness, toughness and solvent resistance. Please click Additional Files below to see the full abstract

Chemo-Protective Effects of Dl-Limonene Unaided and in-Blend with 6-Methyleneandrosta-1, 4-Diene-3, 17-Dione on N-Nitroso-N-Methylurea and Estrogen Sulfotransferase Breast Cancer-Induced Albino Female Rat

Breast cancer is a serious prime hassle commonly diagnosed in women worldwide and it is currently the leading cause of cancer-related mortality. In N-nitroso-N-methylurea (NMU) and estrogen sulfotransferase (EST) breast cancer-induced female rat, the study evaluates the chemo-protective possibilities of DL-limonene (1:1) and its combination with 6-Methyleneandrosta-1, 4, Diene- 3, 17-Dione using standard techniques. Amongst others, data obtained reveals mild areas of clogged blood vessels and pulmonary inflammation revealed in the histopathology section. Interestingly, it's possible that DL-limonene alone at a concentration of 10% could be an effective breast cancer treatment. The findings also revealed that combining DL-limonene with 6-ADD at 5% and 12.5mg/kg could reduce the risk of toxicity associated with higher chemotherapeutic dosages in long-term treatment. Furthermore, at a modest dose, this combination may increase the use of aromatase inhibitors in premenopausal women. Despite the medicinal and therapeutic benefits of DL-limonene, it is best to take it in moderation due to its possible harmful effects on the blood vessels

In Silico Identification of Protein Targets for Drug-like Compounds from Epicarp Extract of Cola rostrata K. Shum

Fruit epicarp has been found to contain several bioactive compounds which are useful for herbal treatment of several ailments and diseases. The phytochemicals present in C. rostrata epicarp as well as their potential to bind to human proteins and modify their function have not been investigated. This study, therefore, identified the top protein targets of drug-like components of C. rostrata epicarp extract in humans as well as the disease conditions associated with the targets. The identities of constituents of methanol and n-hexane fractions of absolute ethanol extract of C. rostrata epicarp were determined via GCMS analysis. Druglikeness (adherence to Lipinski, Ghose, Veber, Egan, and Muegge filters) and the protein targets of drug-like constituents were determined using SwissADME and SwissTargetPrediction web tools. GCMS analyses revealed the presence of 49 compounds in the n-hexane and methanol fractions. Corynan-16-carboxylic acid, 16,17-didehydro-9,17-dimethoxy-, methyl ester, (16E)-, a yohimbine derivative, was abundant (13.33%) in the methanol fraction. The n-hexane fraction was rich in odd-chain fatty acids and phytosterols. Four drug-like compounds were identified in the fractions: (1) Azelaic acid, monoethyl ester; (2) 3-(2-Methoxymethoxyethylidene)-2,2 dimethylbicyclo[2.2.1]heptane; (3) Cyclododecanol, 1-aminomethyl-, and (4) Corynan-16-carboxylic acid, 16,17-didehydro-9,17-dimethoxy-, methyl ester, (16E)-. The predicted top protein targets of the drug-like compounds include carbonic anhydrase II, protein-tyrosine phosphatase 1B, sphingosine kinase 1, maltase-glucoamylase, adenosine A2b receptor, P2X purinoceptor 7, MAP kinase p38 alpha, δ-opioid receptor, and alpha-2 adrenergic receptors. Findings show that C. rostrata epicarp contains drug-like phytochemicals with potential against cancer, diabetes, pain and inflammatory diseases, and the extract could have aphrodisiac potential

A modal theorem-preserving translation of a class of three-valued logics of incomplete information

International audienceThere are several three-valued logical systems that form a scattered landscape, even if all reasonable connectives in three-valued logics can be derived from a few of them. Most papers on this subject neglect the issue of the relevance of such logics in relation with the intended meaning of the third truth-value. Here, we focus on the case where the third truth-value means unknown, as suggested by Kleene. Under such an understanding, we show that any truth-qualified formula in a large range of three-valued logics can be translated into KD as a modal formula of depth 1, with modalities in front of literals only, while preserving all tautologies and inference rules of the original three-valued logic. This simple information logic is a two-tiered classical propositional logic with simple semantics in terms of epistemic states understood as subsets of classical interpretations. We study in particular the translations of Kleene, Gödel, ᴌukasiewicz and Nelson logics. We show that Priest’s logic of paradox, closely connected to Kleene’s, can also be translated into our modal setting, simply by exchanging the modalities possible and necessary. Our work enables the precise expressive power of three-valued logics to be laid bare for the purpose of uncertainty management

Evaluation of the cytotoxic potential of Securidaca longepedunculata on human breast adenocarcinoma (MCF-7) cells

The prevalence of cancer has increased interest in the role of complementary and alternative medicine, employing the use of plant products. Securidaca longepedunculata (SL) is an example of plant product which serves as a major component of anticancer decoctions in Nigeria. In other to scientifically ascertain this claim, this study was carried out to evaluates the cytotoxic potential of the crude extract and fractions of SL root bark against human breast adenocarcinoma (MCF-7) cell line. The root back of SL was pulverized and extracted with 80% methanol to yield a crude extract which was then submitted to liquid–liquid fractionation with dichloromethane (DCM) and butanol (BUT). The extract and fractions were subjected to Gas Chromatography-Mass Spectrometry (GC-MS). MCF-7 cell line was treated with graded concentrations (9.77 – 5000 μg ml-1) of the aqueous methanol crude extract as well as the DCM and BUT fractions for 24 or 48 hours. Cell viability was thereafter measured by XTT proliferation assay. The inhibitory activities of the aqueous methanolic crude extract was found to be both dose-dependent and time independent with IC50 values of 2241 μg ml-1 and 1808 μg ml-1 after 24 and 48 hours respectively. The DCM and BUT fractions were significantly (p < 0.05) cytotoxic with IC50 values of 86.27 μg ml-1 and 12.08 μg ml-1 respectively after 48 hours of treatment. The study provide evidence that BUT fractions of SL has the highest potential to significantly show anticancer properties