Type and conductor of simplicial affine semigroups

We provide a generalization of pseudo-Frobenius numbers of numerical semigroups to the context of the simplicial affine semigroups. In this way, we characterize the Cohen-Macaulay type of the simplicial affine semigroup ring $\mathbb{K}[S]$. We define the type of S, $\mathrm{type}(S)$, in terms of some Apéry sets of S and show that it coincides with the Cohen-Macaulay type of the semigroup ring, when $\mathbb{K}[S]$ is Cohen-Macaulay. If $\mathbb{K}[S]$ is a d-dimensional Cohen-Macaulay ring of embedding dimension at most $d+2$, then $\mathrm{type}(S)\le 2$. Otherwise, $\mathrm{type}(S)$ might be arbitrary large and it has no upper bound in terms of the embedding dimension. Finally, we present a generating set for the conductor of S as an ideal of its normalization.     

A cortisol nanocomposite-based electrochemical sensor for enantioselective recognition of mandelic acid

An electrochemical chiral sensor was designed based on graphene (GR) as a catalyst for signal enhancement. Hydrocortisone has been immobilized as a chiral selector on GR to discriminate electrochemical signals of mandelic acid (MA) enantiomers. A two-step electrodeposition strategy was used to fabricate hydrocortisone-loaded overoxidized polypyrrole film (HC-OPPy) on graphene-modified glassy carbon electrode, which was successfully utilized as a working electrode for direct monitoring of MA enantiomers based on an inhibitory sensing mechanism. The stepwise modification of the surface was confirmed by cyclic voltammetry, impedance spectroscopy, and scanning electron microscopy. Because of the different interactions of enantiomers with the chiral electroactive platform, voltammetric signals with different intensities were observed for S-MA and R-MA at 1.36 and 1.40 V (vs. Ag/AgCl), respectively. The introduced design for the chiral sensor, with exploiting the chemometrics tools such as partial least squares, principle component regression, and genetic algorithm, was able to discriminate highly overlapping signals of MA enantiomers in their mixtures. The hydrocortisone-based sensor showed a linear response towards MA enantiomers within a concentration range of 1.0–25 mM with a detection limit of 0.25 mM (S/N = 3). The sensor not only extends the enantioselective sensing of MA enantiomers but also stimulates new opportunities for investigating stereo-selective behavior of hydrocortisone. The recognition mechanism was also investigated using docking analysis and DFT calculations.

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Simultaneous Determination of Nickel(II) and Copper(II) by Second‐Derivative Spectrophotometric Method in Micellar Media

A second‐derivative spectrophotometric method based on zero‐crossing over technique is developed in simultaneous determination of copper(II) and nickel(II) ions. Methylthymol blue (MTB) as a chromogenic reagent and cetyltrimethylammonium bromide as a surfactant were used, and measurements were carried out in buffered solution at pH 6 and at a temperature of 25 °C. The amplitude of derivative spectra was measured at wavelengths of 631.9 and 587.7 nm for the simultaneous determination of Ni²⁺ and Cu²⁺, respectively. Linearity was obtained in the range of 0.5–5.0 μg mL^?1 for both ions in the presence of 0.0–5.0 μg mL^?1 of the other ion as an interfering ion. IUPAC detection limits for Cu²⁺ and Ni²⁺ ions were obtained at 0.48 and 0.43 μg mL^?1, respectively. The proposed procedure has been applied successfully for the simultaneous determination of copper and nickel in synthetic binary mixtures and real samples.     

Long range behavior of high-rank topological multipole moments

The construction of a high-rank multipolar force field (for peptides) is a complex task, leading to several intermediate questions in need of a clear answer. Here we focus on the convergence of the (electrostatic) multipolar expansion at medium and long range. Using molecular electron densities, quantum chemical topology (QCT) defines the atoms as finite volumes, each endowed with multipole moments. The terms in the multipole expansion are grouped according to powers of the internuclear distance, R(-L). Given two atom types at a given distance, we determine which rank (L) is necessary for the electrostatic energy to converge to the exact interaction energy within a certain error. With this information, the rank of the expansion for each interaction can be adapted to the required accuracy and the available computing power.     

Evaluation of measurement uncertainty in the determination of jasmonic acid in <Emphasis Type="Italic">Lemna minor</Emphasis> L. by liquid chromatography with fluorescence detection

The uncertainty was estimated for the determination of jasmonic acid (JA) content in Lemna minor L. plant extracts using a reverse-phase liquid chromatography with fluorescence detection. JA was extracted from plant material, followed by solid-phase extraction procedures, derivatisation and quantification. In the estimation of uncertainty, the sampling, sample processing and chromatographic determination that may significantly influence the uncertainty of analytical data were considered. The results show that the method recovery and sample homogeneity are the two main contributors to uncertainty. The method has a relative expanded uncertainty (coverage factor k = 2) of about 17% at the JA content of approximately 100 ng/g.     

A perspective on non-enzymatic electrochemical nanosensors for direct detection of pesticides

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Extending Time Profile of Morphine‐Induced Analgesia Using a Chitosan‐Based Molecular Imprinted Polymer Nanogel

Chitosan‐based molecular imprinted polymer (CS‐MIP) nanogel is prepared in the presence of morphine template, fully characterized and used as a new vehicle to extend duration of morphine analgesic effect in Naval Medical Research Institute mice. The CS‐MIP nanogel with ≈25 nm size range exhibits 98% loading efficiency, and in vitro release studies show an initial burst followed by an extended slow release of morphine. In order to study the feasibility of CS‐MIP nanogel as morphine carrier, 20 mice are divided into two groups randomly and received subcutaneous injection of morphine‐loaded CS‐MIP and morphine (10 mg kg^?1) dissolved in physiologic saline. Those received injection of morphine‐loaded CS‐MIP show slower and long lasting release of morphine with 193 min effective time of 50% (ET50) analgesia compared to 120 min ET50 in mice received morphine dissolved in physiologic saline. These results suggest that CS‐MIP nanogel can be a possible strategy as morphine carrier for controlled release and extension of its analgesic efficacy.

     

D-Gulonolactone as a synthon for L-noviose: first preparation of 4-O-demethyl-L-noviofuranose and related derivatives

[reaction: see text] A new synthesis of L-noviose (11), a sugar moiety of novobiocin, is presented. D-Gulonolactone was initially converted in a few steps to the key ester derivative 7 [1-O-benzyl methyl 2,3-O-(1-methylethylidene)-alpha-L-lyxofuranosiduronate]. An appropriate selection of protecting groups enabled transformation of 7 under mild reaction conditions to 4-O-demethyl-L-noviofuranose 9a and related 9b-c. Derivatives 9 were further converted either to L-lyxopyranoses (10a and 10b) or to methyl L-lyxofuranoside 12.     

Induction of tumor necrosis factor-alpha by UVB: a role for reactive oxygen intermediates and eicosanoids

UVB irradiation induces nuclear factor-kappaB (NF-kappaB) activation, tumor necrosis factor-alpha (TNF-alpha) expression and reactive oxygen intermediates (ROI) in keratinocytes. We investigated whether ROI play a role in UVB-induced TNF-alpha mRNA expression. The antioxidants N-acetyl cysteine, NAC, epigallocathin gallate, EGCG, butylated hydroxyanisole (BHA) and vitamin C could reduce UVB-induced TNF-alpha mRNA levels to various degrees; vitamin E (alpha-tocopherol) had no effect. BHA was the most potent inhibitor. The oxidant tertiary butylated hydroperoxide could effectively induce TNF-alpha mRNA expression. Nordihydroguaiaretic acid (NDGA) and MK-886, inhibitors of lipoxygenase (LOX), and indometacin and quinacrine, inhibitors of cyclooxygenase (COX) and phospholipase A2, respectively, could also reduce UVB-induced TNF-alpha mRNA expression. Inhibition by NDGA was in concordance with the results for BHA. NDGA, indometacin, quinacrine and BHA could also effectively inhibit the inhibitor of NF-kappaB degradation, thereby maintaining NF-kappaB inactivity. In conclusion, we show that ROI are implicated in the induction of TNF-alpha mRNA by UVB and that not all antioxidants are equally effective inhibitors. COX products and more importantly LOX products, which themselves are products of an oxidative metabolism, are the main ROI implicated in this induction of TNF-alpha expression by UVB probably via activation of NF-kappaB.     

Reaction of 4-Aryl-3-thiosemicarbazides with Phenylisothiocyanate: A Facile Synthesis of Thiazole,Pyrazole and Pyrimidine Derivatives

The reaction of 4-aryl-3-thiosemicarbazides 1a-d with phenylisothiocyanate gave the intermediate potasium salts 2a-d . The latter afforded 3a-d, 13a-d and 19 upon the reaction with phenacyl bromide, monochloroacetic acid and ethyl bromocyanoacetate respectively.