Template‐Free Synthesis of Highly b‐Oriented MFI‐Type Zeolite Thin Films by Seeded Secondary Growth

Highly b‐oriented, closely packed, MFI zeolite films are prepared on seeded stainless‐steel plates using organic template‐free, secondary growth solutions, containing aluminum sulfate as a crystallization agent. The number of a‐oriented twin crystals is significantly reduced, and even eliminated, simply by restricting the pH value of the secondary growth solution to the narrow range of 11.1–11.3. Values of pH can be adjusted through the controlled addition of (NH₄)₂SO₄ or H₂SO₄ to secondary growth solutions of the composition (1 SiO₂:0.57 NaOH:137.5 H₂O:0.0050 (Al₂(SO₄)₃?18 H₂O)) or by simply decreasing the molar composition of NaOH with no extra additives.     

Ring Opening and Recyclization Reactions with Chromone‐3‐carbonitrile

Chemical transformations of chromone‐3‐carbonitrile ( 1 ) with some substituted hydrazines, namely, thiosemicarbazide, S‐methyl/benzyldithiocarbazate, 7‐chloro‐4‐hydrazinoquinoline, and 3‐hydrazino‐5,6‐diphenyl‐1,2,4‐triazine, led to substituted pyrazoles 2 , 5 – 8 . Ring opening of carbonitrile 1 followed by recyclization with 3‐amino‐1,2,4‐triazole and 2‐aminobenzimidazole gave triazolo[1,5‐a]pyrimidine 9 and pyrimido[1,2‐a]benzimidazole 10 , respectively. Treatment of carbonitrile 1 with some heterocyclic amines produced 2‐amino‐3‐substituted‐chromones 11 and 12 . The novel 3‐hydroxychromeno[4,3‐b]pyrazolo[4,3‐e]pyridin‐5(1H)‐one ( 13 ) was efficiently synthesized from the ring conversion of carbonitrile 1 with cyanoacetohydrazide. A mixture of chromeno[2,3‐b]naphthyridine 14 and chromeno[4,3‐b]pyridine 15 was obtained from base catalyzed transformation of carbonitrile 1 with malononitrile dimer. A diversity of novel annulated chromeno[2,3‐b]pyridines 16 – 22 was also synthesized. Chromeno[2,3‐b]pyrrole‐2‐carboxylate 23 was obtained from the reaction of carbonitrile 1 with ethyl chloroacetate. Structures of the new synthesized products were deduced on the basis of their analytical and spectral data.     

Basal Histamine H4 Receptor Activation: Agonist Mimicry by the Diphenylalanine Motif

Histamine H₄ receptor (H₄R) orthologues are G-protein-coupled receptors (GPCRs) that exhibit species-dependent basal activity. In contrast to the basally inactive mouse H₄R (mH₄R), human H₄R (hH₄R) shows a high degree of basal activity. We have performed long-timescale molecular dynamics simulations and rigidity analyses on wild-type hH₄R, the experimentally characterized hH₄R variants S179M, F169V, F169V+S179M, F168A, and on mH₄R to investigate the molecular nature of the differential basal activity. H₄R variant-dependent differences between essential motifs of GPCR activation and structural stabilities correlate with experimentally determined basal activities and provide a molecular explanation for the differences in basal activation. Strikingly, during the MD simulations, F169^45.55 dips into the orthosteric binding pocket only in the case of hH₄R, thus adopting the role of an agonist and contributing to the stabilization of the active state. The results shed new light on the molecular mechanism of basal H₄R activation that are of importance for other GPCRs.     

Effects of polyvinylpyrrolidone on structural and optical properties of willemite semiconductor nanoparticles by polymer thermal treatment method

Journal of Thermal Analysis and Calorimetry - Willemite is an inorganic semiconductor material used for optoelectronic applications. The present study purposes a new polymer thermal treatment...     

Unsupervised Pattern Recognition Chemometrics for Distinguishing Different Egyptian Olive Varieties Using a New Integrated Densitometric Reversed-Phase High-Performance Thin-Layer Chromatography—Image Analysis Technique

JPC – Journal of Planar Chromatography – Modern TLC - The merits of chemometrics in categorizing different Egyptian olive chemovarieties based on their compositional integrity were...     

Studies on 3,5-diaminopyrazole derivatives

The behaviour of 3,5-diamino-4-phenylazopyrazole toward a variety of reagents is reported. Several new 3,5-diaminopyrazole derivatives as well as amino derivatives of fused pyrazoles have been prepared.

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Untersuchungen an 3,5-Diaminopyrazol-Derivaten

Zusammenfassung Es wird über das Verhalten von 3,5-Diamino-4-phenylazopyrazol gegenüber verschiedenen Agentien berichtet. Es wurden sowohl einige neue 3,5-Diaminooyrazol-Derivate als auch einige Aminoderivate von kondensierten Pyrazolen dargestellt.

     

Synthesis and Crystal Structure of Rubidium Lanthanum Tetraacetate,RbLa(CH3COO)4

The anhydrous rubidium tetraacetato lanthanate, RbLa(CH₃COO)₄, is obtained together with Rb₂La(CH₃COO)₅(H₂O) as colourless single crystals from a 1 : 2 mixture of Rb₂CO₃ and La(CH₃COO) · 1.5 H₂O in acetic acid by slow evaporation. The crystal structure [orthorhombic, Pnnm, Z = 2, a = 1242.0(3), b = 1650.1(4), c = 698.0(4) pm, R = 0.028, R_w = 0.071] contains La³⁺ nine coordinate by oxygen atoms of six acetate ligands. The polyhedra are connected to dimers and further to double chains running parallel to [001]. These [La(CH₃COO)₄]^– double chains are surrounded by four like double chains and connected by Rb⁺ ions that are seven coordinate by oxygen atoms.     

Syntheses and Structures of Heterometallic Fe–Ta Chalcogenido Clusters

Two Fe–Ta containing sulfido complexes were prepared by the reaction of the metal halide salts with bis-trimethylsilylsulfide in the presence of PMe₃. The complexes demonstrate that coordination chemistry with iron sulfides can give access to a range of heterometallic complexes. In [Cl(Me₃P)Ta( ₂-S)₂( ₃-S)Fe(PMe₃)₂]₂ the two [Cl(Me₃P)Ta] units are arranged around one central Fe₂( ₂-S)₂ unit. In [(Me₃P)₄(MeCN)₂Fe^II]²⁺[(Me₃P)₂Ta^IVFe^II ₃( ₃-S)₄Br₄]^2– a [TaFe₃S₄]²⁺ cuboidal arrangement was observed. The complex salt forms a polymeric structure in the solid-state with weak H-bonds between the ions. The [(Me₃P)₂Ta^IVFe^II ₃( ₃-S)₄Br₄]^2– ion was characterised by magnetic measurements showing strong antiferromagnetic interactions between the metal centres.     

Indirect atomic absorption and atomic emission spectrometric determination of antazoline,hydralazine and amiloride hydrochlorides and quinine sulphate

Ion-association complexes of antazoline HCl [I], hydralazine HCl [II], amiloride HCl [III] and quinine sulphate [IV] with [Co(SCN)₄]^2– and [Co(NO₂)₆]^3– were precipitated and the excess unreacted cobalt complex was determined. A new method using atomic emission and atomic absorption spectrometry for the determination of the above drugs in pure solutions and pharmaceutical preparations is given. The drugs can be determined in the ranges 0.3–3.0, 0.19–1.96, 0.3–3.0, and 0.78–7.82 mg/25 ml solutions of I, II, III, and IV, respectively, with mean relative standard deviations of 0.65–2.03 % and recovery values of 95.76–101.2% indicating high precision and accuracy.     

Synthesis and preliminary investigations of the siRNA delivery potential of novel, single-chain rigid cationic carotenoid lipids

The success of nucleic acid delivery requires the development of safe and efficient delivery vectors that overcome cellular barriers for effective transport. Herein we describe the synthesis of a series of novel, single-chain rigid cationic carotenoid lipids and a study of their preliminary in vitro siRNA delivery effectiveness and cellular toxicity. The efficiency of siRNA delivery by the single-chain lipid series was compared with that of known cationic lipid vectors, 3β-[N-(N',N'-dimethylaminoethane)carbamoyl]-cholesterol (DC-Chol) and 1,2-dimyristoyl-sn-glyceryl-3-phosphoethanolamine (EPC) as positive controls. All cationic lipids (controls and single-chain lipids) were co-formulated into liposomes with the neutral co-lipid, 1,2-dioleolyl-sn-glycerol-3-phosphoethanolamine (DOPE). Cationic lipid-siRNA complexes of varying (+/-) molar charge ratios were formulated for delivery into HR5-CL11 cells. Of the five single-chain carotenoid lipids investigated, lipids 1, 2, 3 and 5 displayed significant knockdown efficiency with HR5-CL11 cells. In addition, lipid 1 exhibited the lowest levels of cytotoxicity with cell viability greater than 80% at all (+/-) molar charge ratios studied. This novel, single-chain rigid carotenoid-based cationic lipid represents a new class of transfection vector with excellent cell tolerance, accompanied with encouraging siRNA delivery efficiency.