Indirect determination of amino acids by molecular emission cavity analysis

An indirect method for the determination of ca. 10^?4 M amino acids is described which is based on the reaction of the latter with 2,4,6-trinitrobenzene-1-sulphonic acid at pH 11.7 and the measurement of the S₂ emission in a hydrogen-nitrogen flame that is produced from the resulting compound after the addition of hydrochloric acid. The optimum conditions for the determination of amino acids were investigated. The amino acids examined were glycine, alanine, valine, methionine, serine, threonine and histidine.     

High performance AlxGa1−xN-based avalanche photodiodes

We report high performance solar-blind photodetectors with reproducible avalanche gain as high as 820 under ultraviolet illumination. The solar-blind photodetectors have a sharp cut-off around 276 nm. We improved the device performance by designing different epitaxial wafer structure with thinner active multiplication layer. We compare the resulting fabricated devices from these wafers in terms of dark current, photoresponse, avalanche gain performances.     

The Potential Role of Nigella sativa Seed Oil as Epigenetic Therapy of Cancer

Nigella sativa oil, commonly known as black seed oil (BSO), is a well-known Mediterranean food, and its consumption is associated with beneficial effects on human health. A large number of BSO’s therapeutic properties is attributed to its pharmacologically active compound, thymoquinone (TQ), which inhibits cell proliferation and induces apoptosis by targeting several epigenetic players, including the ubiquitin-like, containing plant homeodomain (PHD) and an interesting new gene, RING finger domains 1 (UHRF1), and its partners, DNA methyltransferase 1 (DNMT1) and histone deacetylase 1 (HDAC1). This study was designed to compare the effects of locally sourced BSO with those of pure TQ on the expression of the epigenetic complex UHRF1/DNMT1/HDAC1 and the related events in several cancer cells. The gas chromatographs obtained from GC-MS analyses of extracted BSO showed that TQ was the major volatile compound. BSO significantly inhibited the proliferation of MCF-7, HeLa and Jurkat cells in a dose-dependent manner, and it induced apoptosis in these cell lines. BSO-induced inhibitory effects were associated with a significant decrease in mRNA expression of UHRF1, DNMT1 and HDAC1. Molecular docking and MD simulation showed that TQ had good binding affinity to UHRF1 and HDAC1. Of note, TQ formed a stable metal coordinate bond with zinc tom, found in the active site of the HDAC1 protein. These findings suggest that the use of TQ-rich BSO represents a promising strategy for epigenetic therapy for both solid and blood tumors through direct targeting of the trimeric epigenetic complex UHRF1/DNMT1/ HDAC1.     

A hybrid wrapper–filter approach to detect the source(s) of out-of-control signals in multivariate manufacturing process

With modern data-acquisition equipment and on-line computers used during production, it is now common to monitor several correlated quality characteristics simultaneously in multivariate processes. Multivariate control charts (MCC) are important tools for monitoring multivariate processes. One difficulty encountered with multivariate control charts is the identification of the variable or group of variables that cause an out-of-control signal. Expert knowledge either in combination with wrapper-based supervised classifier or a pre-filter with wrapper are the standard approaches to detect the sources of out-of-control signal. However gathering expert knowledge in source identification is costly and may introduce human error. Individual univariate control charts (UCC) and decomposition of T²$T^2$ statistics are also used in many cases simultaneously to identify the sources, but these either ignore the correlations between the sources or may take more time with the increase of dimensions. The aim of this paper is to develop a source identification approach that does not need any expert-knowledge and can detect out-of-control signal in less computational complexity. We propose, a hybrid wrapper–filter based source identification approach that hybridizes a Mutual Information (MI) based Maximum Relevance (MR) filter ranking heuristic with an Artificial Neural Network (ANN) based wrapper. The Artificial Neural Network Input Gain Measurement Approximation (ANNIGMA) has been combined with MR (MR-ANNIGMA) to utilize the knowledge about the intrinsic pattern of the quality characteristics computed by the filter for directing the wrapper search process. To compute optimal ANNIGMA score, we also propose a Global MR-ANNIGMA using non-functional relationship between variables which is independent of the derivative of the objective function and has a potential to overcome the local optimization problem of ANN training. The novelty of the proposed approaches is that they combine the advantages of both filter and wrapper approaches and do not require any expert knowledge about the sources of the out-of-control signals. Heuristic score based subset generation process also reduces the search space into polynomial growth which in turns reduces computational time. The proposed approaches were tested by exhaustive experiments using both simulated and real manufacturing data and compared to existing methods including independent filter, wrapper and Multivariate EWMA (MEWMA) methods. The results indicate that the proposed approaches can identify the sources of out-of-control signals more accurately than existing approaches.     

Isostructural copper-zinc mixed metal complexes for single source deposition of Cu-ZnO composite thin films

The mixed metal complex [Zn(TFA)(3)(μ-OH)Cu(3)(dmae)(3)Br]·THF (1) and its isostructural analogues ([Zn(TFA)(3)(μ-OH)Cu(3)(dmae)(3)Cl]·THF (2) and [Zn(TFA)(3)(μ-OH)Cu(3)(dmae)(3)Cl/Br]·THF (3)) have been prepared by a simple metal ligand assembly method and were characterized by their melting points, elemental analysis, IR spectroscopy, thermogravimetry and single crystal X-ray structures. The compounds are distinguished only by the nature of the halide ions and are made up of the same [Zn(TFA)(3)(μ-OH)Cu(3)(dmae)(3)X]·THF molecular building block with Cu(3)ZnO(4) cubane moieties as the central core in which the four metal ions and four oxygen atoms are joined together in alternate positions of the cuboid. All the complexes crystallize with similar packing and crystallographically related symmetry settings, distinguished mainly by the degree of disorder within the complexes and the ordering of the complexes in the structures. The triclinic cell of (1) emulates the monoclinic cell of (2) and is pseudomerohedrally twinned by a symmetry operation of the monoclinic cell. The molecules in (2) are 1:1 disordered around a crystallographic mirror plane. The structure of the mixed halogen compound (3) in turn is a superstructure of the less symmetric structures of (1) and (2) formed by ordering of the complexes along the longest axis of (3). Aerosol-assisted chemical vapour deposition (AACVD) experiments showed that they are promising precursors to deposit thin films of crystalline Cu/ZnO composites. The surface morphology, microstructure, chemical composition and crystallinity of the resulting Cu/ZnO composite thin films were analysed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive X-ray analysis (EDAX), which suggest that the films are thin, crystalline, uniform, smooth and tightly adherent to the substrates with average crystallite sizes in a range between 40.2 and 80.0 nm. Particle sizes, shapes and film morphology were investigated as a function of precursor and decomposition temperature.     

Determination of <Superscript>90</Superscript>Sr, <Superscript>129</Superscript>I and gross beta radioactivity concentration in some teas

In this study, ⁹⁰Sr (540 keVβ ⁻), ¹²⁹I (150 keVβ ⁻) and the gross beta radioactivity concentrations were determined for the samples of tea as the most leading consumed hot drink in the markets (processed and packaged for sale) in our country. Furthermore, the obtained data were statistically analyzed. For determination of ¹²⁹I (150 keVβ⁻), ⁹⁰Sr (540 keVβ⁻) and gross radioactivity concentrations in tea samples, a sensor system consisting of scintillation detector with BP4 probe sensitive to beta radiation and a radiation meter (ST7) configurable for windows at desired power was used.     

N-acylbenzotriazole mediated microwave assisted synthesis of protected and novel unprotected ferrocenoylamidoamino acids

In this study, crystalline and chirally stable carboxyl-protected and novel unprotected N-ferrocenoyl amino acid derivatives of Ser, Cys, Ala, Phe, Trp, Asp and Asn have been prepared. These amino acids undergo substitution reaction with 1-(ferrocenylcarbonyl)-1H-benzotriazole, 1, in partially aqueous media under microwave irradiation.     

Monovalent, clickable, uncharged, water-soluble perylenediimide-cored dendrimers for target-specific fluorescent biolabeling

Herein we report the synthesis of water-soluble polyglycerol-dendronized perylenediimides with a single reactive group that undergoes high-yielding click reactions. Single-molecule studies and target-specific biolabeling are reported, including the highly specific labeling of proteins on the surface of living bacterial and mammalian cells.