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101.
The capability of corona discharge ion mobility spectrometry (CD-IMS) for separation and quantification of sarcosine and L-alanine isomers has been evaluated for the first time. Although these two compounds have the same mass and m/z values in mass spectrometer, ion mobility spectrometry was able to separate and determine them. Variables including carrier gas flow rate, injection and cell temperatures were optimized. The reduced mobilities (K 0) of sarcosine and L-alanine were 1.96 and 1.83, respectively, based on the reduced mobility of nicotinamide. At the optimized conditions the detection limit of sarcosine and L-alanine were 0.7 and 0.9 μg/mL, respectively. The relative standard deviation (RSD) was found to be 6%. Furthermore, a sample injection port of a gas chromatograph was also modified to introduce solvent-free samples into the IMS. 相似文献
102.
103.
Stereoselective Total Synthesis of Oxylipins: (6S,7E,9R,10S)‐6,9,10‐Trihydroxyoctadec‐7‐enoic Acid and (6Z,8R,9R,10S)‐8,9,10‐Trihydroxyoctadec‐6‐enoic Acid
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Jhillu Singh Yadav Kattela Shiva Shankar Anugu Srinivas Reddy Basi V. Subba Reddy 《Helvetica chimica acta》2014,97(4):546-555
The stereoselective total syntheses of oxylipins 1b and 1c are described starting from readily accessible natural sugars via the Grubbs cross‐metathesis, Wittig olefination, and Zn‐mediated reductive elimination as key steps. 相似文献
104.
Pd/C‐Mediated Alkynylation of Indazoles: Synthesis and Pharmacological Evaluation of Mono and Dialkynyl‐Substituted Indazoles
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D. R. Gorja K. Shiva Kumar B. Dulla K. Mukkanti M. Pal 《Journal of heterocyclic chemistry》2014,51(2):374-382
The combination of Pd/C–CuI–PPh3 has been identified as an efficient catalytic system for the C–C bond formation between 6‐bromo‐3‐iodo‐1H‐indazole and terminal alkynes in ethanol. Mono and/or dialkynyl‐substituted indazoles can be prepared using this general and practical methodology in good to excellent yields. Some of the compounds synthesized were tested for cytotoxic activities in vitro. 相似文献
105.
Peapod‐Type Nanocomposites through the In Situ Growth of Gold Nanoparticles within Preformed Hexaniobate Nanoscrolls
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Dr. Shiva Adireddy Cecilia E. Carbo Taha Rostamzadeh Dr. Jose M. Vargas Prof. Leonard Spinu Prof. John B. Wiley 《Angewandte Chemie (International ed. in English)》2014,53(18):4614-4617
A facile in situ method to grow Au nanoparticles (NPs) in hexaniobate nanoscrolls is applied to the formation of plasmonic Au@hexaniobate and bifunctional plasmonic‐magnetic Au‐Fe3O4@hexaniobate nanopeapods (NPPs). Utilizing a solvothermal treatment, rigid multiwalled hexaniobate nanoscrolls and partially filled Fe3O4@hexaniobate NPPs were first fabricated. These nanostructures were then used as templates for the controlled in situ growth of Au NPs. The resulting peapod structures exhibited high filling fractions and long‐range uniformity. Optical measurements showed a progressive red shift in plasmonic behavior between Au NPs, Au NPPs, and Au‐Fe3O4 NPPs; magnetic studies found that the addition of gold in the Fe3O4@hexaniobate NPPs reduced interparticle coupling effects. The development of this approach allows for the routine bulk preparation of noble‐metal‐containing bifunctional nanopeapod materials. 相似文献
106.
Inside Back Cover: Peapod‐Type Nanocomposites through the In Situ Growth of Gold Nanoparticles within Preformed Hexaniobate Nanoscrolls (Angew. Chem. Int. Ed. 18/2014)
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107.
Morteza Hosseini Mohammad Rahimi Hayedeh Bagheri Sadeghi Saeed Taghvaei-Ganjali Shiva Dehghan Abkenar Mohammad Reza Ganjali 《International journal of environmental analytical chemistry》2013,93(6):407-422
A PVC membrane electrode for Hg(II) ions, based on a new cone shaped calix[4]arene (L) as a suitable ionophore was constructed. The sensor exhibits a linear dynamic in the range of 1.0 × 10?6–1.0 × 10?1 M, with a Nernstian slope of 29.4 ± 0.4 mV decade?1, and a detection limit of 4.0 × 10?7 M. The response time is quick (less than 10 s), it can be used in the pH range of 1.5–4, and the electrode response and selectivity remained almost unchanged for about 2 months. The sensor revealed comparatively good selectivity with respect to most alkali, alkaline earth, and some transition and heavy metal ions. It was successfully employed as an indicator electrode in the potentiometric titration of Hg2+ ions with potassium iodide, and the direct determination of mercury content of amalgam alloy and water samples. 相似文献
108.
Javad Safari Hossein Naeimi Ali Akbar Khakpour Ramezan Sharifi Jondani Shiva Dehghan Khalili 《Journal of molecular catalysis. A, Chemical》2007,270(1-2):236-240
In this study we have described the synthesis of new 3-arylidene isobenzofuran-1(3H)-one derivatives. Condensation reaction of phthalic anhydride and quinoline derivatives under solvent-free condition and microwave irradiation in the presence of acetic anhydride as catalyst in good excellent yield is reported. 相似文献
109.
Shiva Shankar 《Acta Appl Math》2003,77(2):163-180
This paper introduces a notion of geometric completeness for spaces of distributions, modelled after the notion of a complete variety in algebraic geometry. It is related to the following elimination problem for systems of PDE: consider the set of homogeneous solutions of a system of PDE in some space of distributions. When is the projection of this set onto some of its coordinates also the set of homogeneous solutions of a system of PDE? 相似文献
110.
Hosseini M Vaezi Z Ganjali MR Faridbod F Abkenar SD 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,83(1):161-164
A new fluorogenic method for selective and sensitive determination of beryllium using 2,6-diphenyl-4-benzo-9-crown-3-pyrane (DBCP) was developed. The proposed fluorescent probe undergoes fluorescent emission intensity enhancement upon binding to beryllium ions in MeOH/H(2)O (70:30, v/v) solution. The fluorescence enhancement of DBCP is attributed to a 1:1 complex formation between DBCP and Be(2+) ion, which has been utilized as the basis for selective detection of Be(2+) ion. With the optimum condition described, the fluorescence enhancement at 531 nm was linear to the concentration of beryllium in the range of 1.6×10(-8)-1.6×10(-7) M and a detection limit of 1.5×10(-9) M. The fluorescent probe exhibits high selectivity for Be(2+) ion over the other common mono, di- and trivalent cations. 相似文献