On the molecules of numerical semigroups, Puiseux monoids, and Puiseux algebras

A molecule is a nonzero non-unit element of an integral domain (resp., commutative cancellative monoid) having a unique factorization into irreducibles (resp., atoms). Here we study the molecules of Puiseux monoids as well as the molecules of their corresponding semigroup algebras, which we call Puiseux algebras. We begin by presenting, in the context of numerical semigroups, some results on the possible cardinalities of the sets of molecules and the sets of reducible molecules (i.e., molecules that are not irreducibles/atoms). Then we study the molecules in the more general context of Puiseux monoids. We construct infinitely many non-isomorphic atomic Puiseux monoids all whose molecules are atoms. In addition, we characterize the molecules of Puiseux monoids generated by rationals with prime denominators. Finally, we turn to investigate the molecules of Puiseux algebras. We provide a characterization of the molecules of the Puiseux algebras corresponding to root-closed Puiseux monoids. Then we use such a characterization to find an infinite class of Puiseux algebras with infinitely many non-associated reducible molecules.Comment: 21 pages, 2 figure

Diversity of vertebrate nicotinic acetylcholine receptors

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Field-amplified sample injection and sweeping micellar electrokinetic chromatography in analysis of glyphosate and aminomethylphosphonic acid in wheat

Glyphosate, a widely used herbicide, has been classified as probably carcinogenic to humans by the International Agency for Research on Cancer (IARC). In the present study a method based on Field-Amplified Sample Injection and Sweeping Micellar Electrokinetic Chromatography (FASI sweep-MEKC) has been developed and validated for determination of glyphosate and its microbial metabolite aminomethylphosphonic acid (AMPA) in wheat flour. The method involved a preliminary solid phase extraction for cleanup of the aqueous extracts from wheat flour, based sequentially on C18 and strong anion exchange cartridges, followed by derivatization using 9-fluorenylmethylchloroformate. Optimization of sample cleanup and derivatization procedure was carried out by a HPLC-UV method, whereas FASI sweep-MEKC was applied for achieving the sensitivity necessary for analysis of real samples. To this regard, optimum conditions involved the use of an extended path fused-silica capillary (80 cm total length, 50 μm, i.d.) filled with a high concentration buffer (sodium phosphate 100 mM, pH 2.2). Electrokinetic sampling was carried out at −10 kV with injection time of 700 s and the separation of the loaded analytes was performed under MEKC conditions using sodium phosphate buffer 50 mM at pH 2.2, supplemented with sodium dodecyl sulfate, 100 mM. The method was validated for linearity, precision, accuracy and sensitivity, showing that using conventional UV detection (210 nm) the achieved limit of quantitation (LOQ) values for both the analytes were widely lower than those set by Authorities. In particular, LOQ for glyphosate and AMPA were found to be 5 and 2.5 ng/mL, respectively, corresponding to 0.1 and 0.05 mg/kg, in wheat flour. The method, applied to commercially available real samples (wheat flour from different manufacturers) and to an experimental sample obtained by cv. Svevo wheat, can be considered as a convenient alternative to the existing approaches in analysis of complex matrices

Nicotinic acetylcholine receptors (nACh) in GtoPdb v.2021.3

Nicotinic acetylcholine (ACh) receptors are members of the Cys-loop family of transmitter-gated ion channels that includes the GABAA, strychnine-sensitive glycine and 5-HT3 receptors [215, 3, 159, 225, 259]. All nicotinic receptors are pentamers in which each of the five subunits contains 4 TM domains. Genes encoding a total of 17 subunits (α1-10, β1-4, γ, δ and ε) have been identified [120]. All subunits with the exception of α8 (present in avian species) have been identified in mammals. All α subunits possess two tandem cysteine residues near to the site involved in acetylcholine binding, and subunits not named α lack these residues [159]. The orthosteric ligand binding site is formed by residues within at least three peptide domains on the α subunit (principal component), and three on the adjacent subunit (complementary component). Nicotinic ACh receptors contain several allosteric modulatory sites. One such site, for positive allosteric modulators (PAMs) and allosteric agonists, has been proposed to reside within an intrasubunit cavity between the 4 TM domains [264, 87]; see also [106]). The high resolution crystal structure of the molluscan ACh binding protein, a structural homologue of the extracellular binding domain of a nicotinic receptor pentamer, in complex with several nicotinic receptor ligands (e.g.[35]) and the crystal structure of the extracellular domain of the α1 subunit bound to α-bungarotoxin at 1.94Â resolution [55], has revealed the orthosteric binding site in detail (reviewed in [215, 120, 39, 198]). Nicotinic receptors at the somatic neuromuscular junction of adult animals have the stoichiometry (α1)2β1δε, whereas an extrajunctional (α1)2β1γδ receptor predominates in embryonic and denervated skeletal muscle and other pathological states. Other nicotinic receptors are assembled as combinations of α(2-6) and β(2-4) subunits. For α2, α3, α4 and β2 and β4 subunits, pairwise combinations of α and β (e.g. α3β4 and α4β2) are sufficient to form a functional receptor in vitro, but far more complex isoforms may exist in vivo (reviewed in [96, 93, 159]). There is strong evidence that the pairwise assembly of some α and β subunits can occur with variable stoichiometry [e.g. (α4)2(β2)2 or (α4)3(β2)2] which influences the biophysical and pharmacological properties of the receptor [159]. α5 and β3 subunits lack function when expressed alone, or pairwise, but participate in the formation of functional hetero-oligomeric receptors when expressed as a third subunit with another α and β pair [e.g. α4α5αβ2, α4αβ2β3, α5α6β2, see [159] for further examples]. The α6 subunit can form a functional receptor when co-expressed with β4 in vitro, but more efficient expression ensues from incorporation of a third partner, such as β3 [263]. The α7, α8, and α9 subunits form functional homo-oligomers, but can also combine with a second subunit to constitute a hetero-oligomeric assembly (e.g. α7β2 and α9α10). For functional expression of the α10 subunit, co-assembly with α9 is necessary. The latter, along with the α10 subunit, appears to be largely confined to cochlear and vestibular hair cells. Comprehensive listings of nicotinic receptor subunit combinations identified from recombinant expression systems, or in vivo, are given in [159]. In addition, numerous proteins interact with nicotinic ACh receptors modifying their assembly, trafficking to and from the cell surface, and activation by ACh (reviewed by [158, 9, 118]).The nicotinic receptor Subcommittee of NC-IUPHAR has recommended a nomenclature and classification scheme for nicotinic acetylcholine (nACh) receptors based on the subunit composition of known, naturally- and/or heterologously-expressed nACh receptor subtypes [143]. Headings for this table reflect abbreviations designating nACh receptor subtypes based on the predominant α subunit contained in that receptor subtype. An asterisk following the indicated α subunit denotes that other subunits are known to, or may, assemble with the indicated α subunit to form the designated nACh receptor subtype(s). Where subunit stoichiometries within a specific nACh receptor subtype are known, numbers of a particular subunit larger than 1 are indicated by a subscript following the subunit (enclosed in parentheses- see also [46])

Study on the antibacterial properties of leathers tanned with natural tannins and their interactions with shoes inhabiting bacteria

Content: Tannins are high molecular weight polyphenols, naturally synthesized by plants to defend themselves against biotic and abiotic stress factors. Their role as antioxidant, antibiotic and antibacterial agent has been known for many years among agriculture, food, pharma and cosmetics industry. If tannins would perform an antibacterial activity in a vegetable tanned leather, the leather itself could be certified as an antibacterial material. This effect could be very interesting for all the applications in which the leather, being in contact with sweat and bacteria, becomes a solution to reduce more or less severe hyperhidrosis and bromhidrosis. The goal of the study was the assessment of the antibacterial activity of vegetable tanned leathers with natural tannins to produce articles in direct contact with human skin and, therefore, their effect on sweat, bacterial growth and metabolite production. Firstly, the antibacterial activity has been evaluated and compared between leathers tanned with Chestnut, Quebracho and Tara extracts, chrome tanned leathers and synthetic materials. The trial was performed in vitro by inoculating gram positive (Staphylococcus aureus) and gram negative (Escherichia coli) bacterial strains. A later step defined the most suitable blend of tannins to obtain, after tanning and/or retanning, an antibacterial natural leather. Furthermore, the vegetable tanned leathers, made with this tannins blend, have been the target of an in vivo trial during which 15 panelists have worn two differently made shoes. The lining and insole inside the right shoe have been made with vegetable tanned leathers with tannins, while the ones inside the left shoe contained only synthetic material. The shoes have been worn for 28 consecutive days, followed by a molecular and bioinformatic analysis of microbiota samples taken from the inner surface of the shoes by using a sterile swab. Lastly, a biochemical analysis of volatile short chain fatty acids has been carried out to investigate the byproducts of the bacteria responsible for the unpleasant odor of shoes. Take-Away: 1. Vegetable tanned leather is a wonderful antibacterial material thanks to the presence of natural tannins, such as chestnut, quebracho and tara. This property is appreciated in the production of insole leather, lining, leather goods and automotive interiors. 2. The problem of bromhidrosis (bad feet odor) can be avoided by using vegetable tanned leather. 3. In particular, vegetable leathers tanned with tannins used to make inside part of the shoes permit to avoid the formation of cheesy and acidic odours thanks to their antibacterial properties and their capacity to absorb sweat

Frequency Domain Functional Near-Infrared Spectrometer (fNIRS) for Crew State Monitoring

A frequency domain functional near-infrared spectrometer (fNIRS) and accompanying software have been developed by the NASA Glenn Research Center as part of the Airspace Operations and Safety Program (AOSP) Technologies for Airplane State Awareness (TASA)SE211 Crew State Monitoring (CSM) Project. The goal of CSM was to develop a suite of instruments to measure the cognitive state of operators while performing operational activities. The fNIRS was one of the instruments intended for the CSM, developed to measure changes in oxygen levels in the brain noninvasively

Application of experimental design methodologies in the enantioseparation of pharmaceuticals by capillary electrophoresis: a review

Chirality is one of the major issues in pharmaceutical research and industry. Capillary electrophoresis (CE) is an interesting alternative to the more frequently used chromatographic techniques in the enantioseparation of pharmaceuticals, and is used for the determination of enantiomeric ratio, enantiomeric purity, and in pharmacokinetic studies. Traditionally, optimization of CE methods is performed using a univariate one factor at a time (OFAT) approach; however, this strategy does not allow for the evaluation of interactions between experimental factors, which may result in ineffective method development and optimization. In the last two decades, Design of Experiments (DoE) has been frequently employed to better understand the multidimensional effects and interactions of the input factors on the output responses of analytical CE methods. DoE can be divided into two types: screening and optimization designs. Furthermore, using Quality by Design (QbD) methodology to develop CE-based enantioselective techniques is becoming increasingly popular. The review presents the current use of DoE methodologies in CE-based enantioresolution method development and provides an overview of DoE applications in the optimization and validation of CE enantioselective procedures in the last 25 years. Moreover, a critical perspective on how different DoE strategies can aid in the optimization of enantioseparation procedures is presented