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991.
Yusuf Sicak Emine E. Oruç-Emre Mehmet Öztürk Ayşegül Karaküçük-İyidoğan Said Nadeem 《Journal of heterocyclic chemistry》2020,57(2):830-841
Twenty-four pyrazolo derivatives (1–4)(a-f) were synthesized and characterized by FTIR, 1H, and 13C NMR (Nuclear Magnetic Resonance), and elemental analysis. The synthesized compounds were also investigated for their antioxidant and anticholinesterase activities. The compounds (3–4)(a-f) carrying morpholine ring were more active than the piperidinyl containing compounds (1–2)(a-f) in both activities. The compound 4f showed higher activity in both assays as compared with the others. Additionally, the anticholinesterase activity test provided higher values than the galantamine in the BChE assay. Therefore, compound 4f can be used as anticholinesterase agent and/or anticholinesterase assay standard. 相似文献
992.
993.
Syed Lal Badshah Anila Riaz Akhtar Muhammad Gülsen Tel ayan Fatih ayan Mehmet Emin Duru Nasir Ahmad Abdul-Hamid Emwas Mariusz Jaremko 《Molecules (Basel, Switzerland)》2021,26(5)
Mushroom polysaccharides are active medicinal compounds that possess immune-modulatory and anticancer properties. Currently, the mushroom polysaccharides krestin, lentinan, and polysaccharopeptides are used as anticancer drugs. They are an unexplored source of natural products with huge potential in both the medicinal and nutraceutical industries. The northern parts of Pakistan have a rich biodiversity of mushrooms that grow during different seasons of the year. Here we selected an edible Morchella esculenta (true morels) of the Ascomycota group for polysaccharide isolation and characterization. Polysaccharopeptides and polysaccharides from this mushroom were isolated using the green chemistry, hot water treatment method. Fourier transform infrared spectroscopy revealed the sugar nature and possible beta-glucan type structure of these polysaccharides. Antioxidant assays showed that the deproteinized polysaccharides have moderate free radical scavenging activity. These isolated polysaccharides exhibited good acetylcholinesterase (AChE) and butyryl cholinesterase (BChE) inhibition activities. Therefore, these polysaccharides may be valuable for the treatment of Alzheimer’s and Parkinson’s diseases. Further bioassays are needed to discover the true potential of M. esculenta polysaccharides for medicinal purposes. 相似文献
994.
Ca3[BN2]I3: The First Halide‐Rich Alkaline Earth Nitridoborate with Isolated [BN2]3– Units 下载免费PDF全文
Turna Ezgi Toros Müjde Yahyaoglu Umut Aydemir Christina Drathen Lev Akselrud Yurii Prots Peter Höhn Mehmet Somer 《无机化学与普通化学杂志》2015,641(11):2014-2019
The title compound Ca3[BN2]I3 was obtained from reactions of mixtures of the starting materials Ca3[BN2]2 and CaI2 in a 1:4 ratio in sealed Nb tubes at 1223 K. The crystal structure was solved from powder synchrotron diffraction data. Ca3[BN2]I3 is the first example of a halide‐rich nitridoborate crystallizing in the rhombohedral space group R32 [no. 155, Pearson code: hR96; Z = 12; a = 16.70491(2) Å, c = 12.41024(2) Å]. The crystal structure is built up by two interpenetrating networks of condensed edge‐sharing [BN2]@Ca6 and [□]@I6 trigonal antiprisms (□ = void). In Ca3[BN2]I3 two crystallograhically distinct [BN2]3– anions are present with d(B1–N) = 1.393(2) Å and d(B2–N) = 1.369(9) Å. Their bond angles are practically linear, varying only slightly: N–B1–N = 179(1)° and N–B2–N = 180°. Vibrational spectra were interpreted based on the D∞h symmetry of the discrete linear [N–B–N]3– moieties, considering the site symmetry reduction and the presence of two distinct [BN2]3– groups. 相似文献
995.
Mehmet Aydın Ülkü Alver Şahin 《International journal of environmental analytical chemistry》2017,97(4):368-382
This study details the metal and metalloid accumulation profiles of three species of sea cucumbers (Holothuriamammata, Holothuriapolii and Holothuriatubulosa) native to Alia?a and Ild?r (?zmir, Turkey), two regions that are representative of industrial and residential districts, respectively. A total of 11 elements were analysed (Fe, Cu, Mn, Zn, Cr, Co, V, Ni, Cd, Pb and As) from gut and body wall tissues of holothurians and in sediment samples. The Mann–Whitney U analysis revealed statistical difference between locations and tissues. Accumulations of Alia?a samples were significantly higher than Ild?r samples with respect to Zn, V, Mn, Cr, Fe and Co while accumulations were significantly higher in the gut than body wall regardless of the region for all elements tested. The correlation analysis showed more and stronger correlations in the gut than in the body wall. In addition, metal(loid) concentrations in the sediment were found to correlate strongly with these in the sea cucumber gut. The cluster analysis displayed totally different element accumulation pattern for Alia?a and Ild?r in the both tissues which indicate that anthropogenic effects start to alter the bioaccumulation of metal(loids). Biota-sediment accumulation factors (BSAF) and metal contamination index were calculated to determine the extent of metal(loid) uptake and to compare total elemental accumulation at each region. Gut tissue elemental BSAF is higher than body wall for all elements at both areas. Cd has the highest value with 5.582 (gut tissue) and the lowest are Ni, V and Cr with 0.001 (body wall tissue). In addition, sediment results were compared with previous studies and sediment quality guidelines and found to exceed the lowest effect level (LEL) values for As and Ni. 相似文献
996.
In this study, hydrophilic and fouling-resistant polysulfone (PS) membranes were fabricated using the phase inversion method to reduce membrane fouling caused by microalgal culture. The Pluronic F-127 polymer, which is used as a hydrophilic co-polymer, was added to the membranes to improve the membrane properties. Characteristic specifications of the fabricated membranes, such as morphology, surface roughness, chemical structures and hydrophobicity/hydrophilicity, were studied using scanning electron microscopy, atomic force microscopy (AFM), energy-dispersive X-ray spectroscopy (EDS), attenuated total reflection-fourier infrared (ATR-FTIR) spectroscopy and contact angle devices. According to the results obtained, it was observed that, with the increase of the Pluronic F-127 concentration in the membranes, the surface roughness of the membranes decreased and hydrophilicity and permeation fluxes increased notably. Furthermore, it was observed that the addition of the Pluronic F-127 polymer into the membranes reduced reversible/irreversible membrane fouling. Additionally, a characterisation of the fouled membranes was performed for the purpose of comprehensively understanding the membrane fouling mechanism caused by microalgal culture. 相似文献
997.
A cellulose–graphite oxide composite was synthesized and characterized as an adsorbent for dispersive solid-phase extraction of rhodium from various samples before atomic absorption detection. The pH, adsorbent volume, centrifugation time and rate, eluent concentration, volume and type, adsorption and elution contact time, sample volume, and matrix interferences were optimized. The developed method is simple, rapid, and inexpensive. The tolerance limits for rhodium were 10,000?mg?L?1 sodium, 25,000?mg?L?1 potassium, 10,000?mg?L?1 magnesium, and 20,000?mg?L?1 calcium. The recovery for rhodium exceeded 95%. Elution was performed with 10?mL of 2.5?mol?L?1 H2SO4. The adsorption and elution contact times were 30 and 60?s, respectively. The detection limit of the method for rhodium was 5.4?µg?L?1 and the precision as the relative standard deviation was 1.6%. A certified reference material 2556 (used auto catalyst pellets) and fortified samples were analyzed to evaluate the accuracy of the method. The optimized method was used for the preconcentration of rhodium from tap water, well water, wastewater, seawater, catalytic converters, and street dust. 相似文献
998.
On complete pseudoconvex Reinhardt domains in ?2, we show that there is no nonzero Hankel operator with anti-holomorphic symbol that is Hilbert-Schmidt. In the proof, we explicitly use the pseudoconvexity property of the domain. We also present two examples of unbounded non-pseudoconvex domains in ?2 that admit nonzero Hilbert-Schmidt Hankel operators with anti-holomorphic symbols. In the first example the Bergman space is finite dimensional. However, in the second example the Bergman space is infinite dimensional and the Hankel operator \({H_{{{\bar z}_1}{{\bar z}_2}}}\) is Hilbert-Schmidt. 相似文献
999.
In this study, by using the concepts and results on spherical curves in dual Lorentzian space, we give the criterions for ruled surfaces with non‐lightlike ruling to be closed (periodic). Moreover, we obtain the necessary and sufficient conditions to guarantee that a timelike or a spacelike ruled surface is closed (periodic). Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
1000.
The aim of this study was to investigate and compare the flame retardant properties of boron compounds with respect to aluminum trihydroxide (ATH) in an epoxy system based on bisphenol A epichlorohydrin‐based epoxy resin and cycloaliphatic polyamine‐based hardener. Six different boron compounds including colemanite (C), ulexite (U), boric acid (BA), boric oxide (BO), melamine borate (MB) and guanidinium nonaborate (GB) were used as flame retardant additive. The flame retardant properties of epoxy‐based composites were investigated using limiting oxygen index (LOI), UL 94 standards both in vertical and horizontal position, thermogravimetric analysis, cone calorimeter and scanning electron microscopy. According to flammability test results, boron compounds except for C and U showed better performance than ATH. According to the LOI results, 40% BA containing sample had the highest LOI value of 28.5, while 30% MB, 35% GB and 40% BA containing samples had the highest UL 94V rating (V0). According to the cone calorimeter test results, all boron containing samples had better fire performances than ATH containing sample; 40 wt% BO containing sample showed the lowest peak heat release rate, average heat release rate and total heat release values. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献