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171.
Thidar Oo Bhanubong Saiboonjan Sukanya Srijampa Arpasiri Srisrattakarn Khaetthareeya Sutthanut Ratree Tavichakorntrakool Aroonwadee Chanawong Aroonlug Lulitanond Patcharaporn Tippayawat 《Molecules (Basel, Switzerland)》2021,26(15)
Myristicafragrans Houtt. (Nutmeg) is a widely known folk medicine across several parts of Asia, particularly used in antimicrobial treatment. Bacterial resistance involves the expression of efflux pump systems (chromosomal norA and mepA) in methicillin-resistant Staphylococcus aureus (MRSA). Crude extract (CE) and essential oil (EO) obtained from nutmeg were applied as efflux pump inhibitors (EPIs), thereby enhancing the antimicrobial activity of the drugs they were used in. The major substances in CE and EO, which function as EPIs, in a descending order of % peak area include elemicin, myristicin, methoxyeugenol, myristicin, and asarone. Here, we investigated whether the low amount of CE and EO used as EPIs was sufficient to sensitize MRSA killing using the antibiotic ciprofloxacin, which acts as an efflux system. Interestingly, synergy between ciprofloxacin and CE or EO revealed the most significant viability of MRSA, depending on norA and mepA, the latter being responsible for EPI function of EO. Therefore, CE and EO obtained from nutmeg can act as EPIs in combination with substances that act as efflux systems, thereby ensuring that the MRSA strain is susceptible to antibiotic treatment. 相似文献
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173.
Anuj Krishna N. Vijayan B. Riscob B. S. Gour D. Haranath J. Philip S. Verma M. S. Jayalakshmy G. Bhagavannarayana S. K. Halder 《Applied Physics A: Materials Science & Processing》2014,114(4):1257-1265
A potential semiorganic nonlinear optical material, L-alanine cadmium chloride monohydrate has been successfully synthesised and single crystals have been grown by slow evaporation solution growth technique at room temperature by using double distilled water as the solvent. The lattice dimensions of the grown crystal have been analysed by adopting powder X-ray diffraction technique and found that it crystallised in monoclinic system with space group C2. The crystalline perfection of the as-grown crystal has been assessed by high resolution X-ray diffraction and X-ray topography techniques and observed that the quality of the grown specimen is reasonably good. Its optical properties were examined by UV–Vis and photoluminescence techniques and found that there is no absorption in the entire visible range. Its functional groups were identified from FT-Raman and observed that there is no incorporation of other impurities during crystallisation. Its relative second harmonic generation efficiency has been tested with different particle size by Kurtz powder technique and found that within the coherence length the title compound is phase matchable. Its various thermal properties like thermal conductivity, specific heat, thermal effusivity, etc. have been evaluated by photopyroelectric technique and compared with other organic and inorganic materials. To confirm its piezoelectric response, its piezoelectric charge coefficient was measured using piezometer and found low. Its optical homogeneity as well as birefringence measurement of the grown specimen has been carried out by interferometric technique. The surface defects of the grown LACCM single crystal were analysed with etching at room temperature using water as an etchant. 相似文献
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175.
The performance of Maximum a posteriori (MAP) estimation is studied analytically for binary symmetric multi-channel Hidden Markov processes. We reduce the estimation problem to a 1D Ising spin model and define order parameters that correspond to different characteristics of the MAP-estimated sequence. The solution to the MAP estimation problem has different operational regimes separated by first order phase transitions. The transition points for L-channel system with identical noise levels, are uniquely determined by L being odd or even, irrespective of the actual number of channels. We demonstrate that for lower noise intensities, the number of solutions is uniquely determined for odd L, whereas for even L there are exponentially many solutions. We also develop a semi analytical approach to calculate the estimation error without resorting to brute force simulations. Finally, we examine the tradeoff between a system with single low-noise channel and one with multiple noisy channels. 相似文献
176.
Heinz-Richard Halder 《Journal of Geometry》1974,5(2):147-157
In this paper we get necessary conditions for the existence of (k,n)-arcs K with the following property: Each point of K is incident with exactly m lines intersecting K in exactly m points. We prove that the set of tangent lines of such arcs forms an arc of the same type in the dual plane. Moreover we determine an upper bound for k for the existence of m-regular (k,n)-arcs. 相似文献
177.
S. Halder P. Gerber T. Schneller R. Waser 《Applied Physics A: Materials Science & Processing》2005,81(1):11-13
The electromechanical properties of thin films of barium titanate zirconate were studied with the help of a double-beam interferometer. Thin films of barium titanate zirconate (Ba(Ti1-xZrx)O3) of various compositions (x=0, 0.03, 0.05, 0.07, 0.1, 0.2, 0.3 and 0.4) were deposited by chemical solution deposition on Pt/TiO2/SiO2/Si substrates. The thin films show a strain of around 0.05 (at 200 kV/cm) for the unsubstituted BaTiO3 thin films. For higher Zr substitutions up to 5% the strain increases slightly and subsequently falls to 0.01 at 200 kV/cm for even higher Zr content. The d33 values were found to vary between 30 pm/V and 10 pm/V for 0x0.4. PACS 77.65.-j; 77.55.+f; 77.84.Dy 相似文献
178.
Ultrastable Imine‐Based Covalent Organic Frameworks for Sulfuric Acid Recovery: An Effect of Interlayer Hydrogen Bonding
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Arjun Halder Suvendu Karak Dr. Matthew Addicoat Saibal Bera Dr. Amit Chakraborty Shebeeb H. Kunjattu Dr. Pradip Pachfule Prof. Dr. Thomas Heine Prof. Dr. Rahul Banerjee 《Angewandte Chemie (International ed. in English)》2018,57(20):5797-5802
A rapid and scalable synthesis of six new imine‐linked highly porous and crystalline COFs is presented that feature exceptionally high chemical stability in harsh environments including conc. H2SO4 (18 m ), conc. HCl (12 m ), and NaOH (9 m ). This is because of the presence of strong interlayer C?H???N hydrogen bonding among the individual layers, which provides significant steric hindrance and a hydrophobic environment around the imine (?C=N?) bonds, thus preventing their hydrolysis in such an abrasive environment. These COFs were further converted into porous, crystalline, self‐standing, and crack‐free COF membranes (COFMs) with extremely high chemical stability for their potential applications for sulfuric acid recovery. The as‐synthesized COFMs exhibit unprecedented permeance for acetonitrile (280 Lm?2 h?1 bar?1) and acetone (260 Lm?2 h?1 bar?1). 相似文献
179.
180.
Reaction of salicyldehyde thosemicarbazone (H2L1), 2-hydroxyacetophenone thiosemicarbazone (H2L2) and 2-hydroxynapthaldehyde thiosemicarbazone (H2L3) (general abbreviation H2L, where H2 stands for the two dissociable protons, one phenolic proton and one hydrazinic proton) with K2[PtCl4] afforded a family of polymeric complexes of type [{Pt(L)}n]. Reaction of the polymeric species with two monodentate ligands (D), viz. triphenylphosphine (PPh3) and 4-picoline (pic), yielded complexes of the type [Pt(L)(D)]. These mixed-ligand complexes were also obtained from the reaction of the thiosemicarbazones with [Pt(PPh3)2Cl2] and [Pt(pic)2Cl2]. The crystal structure of [Pt(PPh3)(L2)] has been determined. The thiosemicarbazone ligands are coordinated, via dissociation of the two protons, as dianionic tridentate O,N,S-donors. The [Pt(L)(D)] complexes show characteristic 1H NMR spectra and intense absorptions in the visible and ultraviolet region. They also fluoresce in the visible region at ambient temperature. 相似文献