Taking laboratory uncertainties into account in the Hampel estimator

Accreditation and Quality Assurance - According to ISO/IEC 17025:2017, testing and calibration laboratories should apply procedures for estimating measurement uncertainty. It would thus make sense...     

The effect of platinum electrode surfaces on precise primary pH measurements

Journal of Solid State Electrochemistry - For primary pH measurements, a platinum hydrogen electrode and a silver chloride electrode are immersed in the same solution in a cell without transference...     

Pyrimidine Derivatives with Terminal Pyridyl Heterocycles: Facile Synthesis and Their Antiproliferative Activities

Incorporation of heterocyclic pyrimidine or pyridine motifs is common in the drug design for various therapeutic applications. Herein, we describe the facile synthesis of two molecules containing both pyrimidine and pyridine scaffolds. A variety of analytical techniques (multinuclear NMR, Fourier transform infrared, and mass spectrometry analyses) confirmed the purity of these molecules. In pristine form, their potential as antitumor drugs was screened by investigating their cytotoxicity against various cell lines (cancerous and normal cells). Experimental results confirmed that the two molecules exhibited cell growth inhibition at very low concentrations. This was evident from their IC₅₀ values that are in the range of 0.45–2.20 μM.     

Metabolomics Based on MS in Mice with Diet-Induced Obesity and Type 2 Diabetes Mellitus: the Effect of Vildagliptin,Metformin, and Their Combination

Applied Biochemistry and Biotechnology - Type 2 diabetes mellitus (T2DM) is a major epidemiological problem. Metformin and vildagliptin are well-established antidiabetic drugs. The aim of the study...     

Eco-friendly synthesis,in vitro anti-proliferative evaluation,and 3D-QSAR analysis of a novel series of monocationic 2-aryl/heteroaryl-substituted 6-(2-imidazolinyl)benzothiazole mesylates

Abstract

Herein, we describe the synthesis of twenty-one novel water-soluble monocationic 2-aryl/heteroaryl-substituted 6-(2-imidazolinyl)benzothiazole mesylates 3a–3u and present the results of their anti-proliferative assays. Efficient syntheses were achieved by three complementary simple two-step synthetic protocols based on the condensation reaction of aryl/heteroaryl carbaldehydes or carboxylic acid. We developed an eco-friendly synthetic protocol using glycerol as green solvent, particularly appropriate for the condensation of thermally and acid-sensitive heterocycles such as furan, benzofuran, pyrrole, and indole. Screening of anti-proliferative activity was performed on four human tumour cell lines in vitro including pancreatic cancer (CFPAC-1), metastatic colon cancer (SW620), hepatocellular carcinoma (HepG2), and cervical cancer (HeLa), as well as in normal human fibroblast cell lines. All tested compounds showed strong to moderate anti-proliferative activity on tested cell lines depending on the structure containing aryl/heteroaryl moiety coupled to 6-(2-imidazolinyl)benzothiazole moiety. The most potent cytostatic effects on all tested cell lines with \(\hbox {IC}_{50}\) values ranging from 0.1 to 3.70 \(\upmu \hbox {M}\) were observed for benzothiazoles substituted with naphthalene-2-yl 3c, benzofuran-2-yl 3e, indole-3-yl 3j, indole-2-yl 3k, quinoline-2-yl 3s, and quinoline-3-yl 3t and derivatives substituted with phenyl 3a, naphthalene-1-yl 3b, benzothiazole-2-yl 3g, benzothiazole-6-yl 3h, N-methylindole-3-yl 3l, benzimidazole-2-yl 3n, benzimidazole-5(6)-yl 3o, and quinolone-4-yl 3u with \(\hbox {IC}_{50}\) values ranging from 1.1 to 29.1 \(\upmu \hbox {M}\). Based on obtained anti-proliferative activities, 3D-QSAR models for five cell lines were derived. Molecular volume, molecular surface, the sum of hydrophobic surface areas, molecular mass, and possibility of making dispersion forces were identified by QSAR analyses as molecular properties that are positively correlated with anti-proliferative activity, while compound’s capability to accept H-bond was identified as a negatively correlated property. Comparison of molecular properties identified for different cell lines enabled assumptions about similarity of mode of action through which anti-proliferative activities against different cell lines are accomplished. Novel compounds that are predicted to have enhanced activities in comparison with herein presented ones were designed using 3D-QSAR analysis as guideline.

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A comprehensive study of classification methods for medical diagnosis

In this model study, we developed a method to distinguish between breast cancer cells and normal epithelial cells, which is in principal suitable for online diagnosis by Raman spectroscopy. Two cell lines were chosen as model systems for cancer and normal tissue. Both cell lines consist of epithelial cells, but the cells of the MCF‐7 series are carcinogenic, where the MCF‐10A cells are normal growing. An algorithm is presented for distinguishing cells of the MCF‐7 and MCF‐10A cell lines, which has an accuracy rate of above 99%. For this purpose, two classification steps are utilized. The first step, the so‐called top‐level classifier searches for Raman spectra, which are measured in the nuclei region. In the second step, a wide range of discriminant models are possible and these models are compared. The classification rates are always estimated using a cross‐validation and a holdout‐validation procedure to ensure the ability of the routine diagnosis to work in clinical environments. Copyright © 2009 John Wiley & Sons, Ltd.     

Low voltage operating OFETs based on solution-processed metal phthalocyanines

The class of sodium salts of sulphonated metal phthalocyanines (MePCS _x , S = SO₃Na, x=1–4) was investigated as a p-type channel component in organic field-effect transistors (OFETs). The solubility of these materials appears to be enhanced compared to their non-sulphonated counterparts (MePCs). We fabricated transistors based on MePCS _x varying the central metal atom (Me = Ni, Co, Zn, Al) and we evaluated the dependence of transistor performance on the nature of the central atom and the degree of sulphonation. The best results were obtained in the case of Ni and low sulphur content. In this case the mobility value is μ=1.08 cm² V⁻¹ s⁻¹ and the on/off current ratio ∼10³. The degree of sulphonation affects the electric field inside the active film in a way analogous to the case of polyelectrolyte-gated OFETs. The Na⁺ counter ions present in the channel contribute to the device characteristics but their concentration should be controlled in order to optimize device performance.     

Improved functional mapping of the human amygdala using a standard functional magnetic resonance imaging sequence with simple modifications

As the amygdala is involved in various aspects of emotional processing, its characterization using neuroimaging modalities, such as functional magnetic resonance imaging (fMRI), is of great interest. However, in fMRI, the amygdala region suffers from susceptibility artifacts that are composed of signal dropouts and image distortions. Various technically demanding approaches to reduce these artifacts have been proposed, and most require alterations beyond a mere change of the acquisition parameters and cannot be easily implemented by the user without changing the MR sequence code. In the present study, we therefore evaluated the impact of simple alterations of the acquisition parameters of a standard gradient-echo echo-planar imaging technique at 3 T composed of echo times (TEs) of 27 and 36 ms as well as section thicknesses of 2 and 4 mm while retaining a section orientation parallel to the intercommissural plane and an in-plane resolution of 2x2 mm(2). In contrast to previous studies, we based our evaluation on the resulting activation maps using an emotional stimulation paradigm rather than on MR raw image quality only. Furthermore, we tested the effects of spatial smoothing of the functional raw data in the course of postprocessing using spatial filters of 4 and 8 mm. Regarding MR raw image quality, a TE of 27 ms and 2-mm sections resulted in the least susceptibility artifacts in the anteromedial aspect of the temporal lobe. The emotional stimulation paradigm resulted in robust bilateral amygdala activation for the approaches with 2-mm sections only -- but with larger activation volumes for a TE of 36 ms as compared with that of 27 ms. Moderate smoothing with a 4-mm spatial filter represented a good compromise between increased sensitivity and preserved specificity. In summary, we showed that rather than applying advanced modifications of the MR sequence, a simple increase in spatial resolution (i.e., the reduction of section thickness) is sufficient to improve the detectability of amygdala activation.     

Entanglement in the Quantum Ising Model

We study the asymptotic scaling of the entanglement of a block of spins for the ground state of the one-dimensional quantum Ising model with transverse field. When the field is sufficiently strong, the entanglement grows at most logarithmically in the number of spins. The proof utilises a transformation to a model of classical probability called the continuum random-cluster model, and is based on a property of the latter model termed ratio weak-mixing. In an intermediate result, we establish an exponentially decaying bound on the operator norm of differences of the reduced density operator. Of special interest is the mathematical rigour of this work, and the fact that the proof applies equally to a large class of disordered interactions.     

New organic FET-like photoactive device, experiments and DFT modeling

We present the possible construction of an organic FET-like photoactive device in which source-drain current through a phthalocyanine ( H₂Pc film is affected by a photo-induced dipolar field in a photoactive “gate” electrode. The influence of the dipolar electric field on charge transfer between H₂Pc molecules is modeled by DFT quantum-chemical calculations on H₂Pc dimers and tetramers.