Read by QxMD icon Read


Simon Drescher, Christian Otto, Sindy Müller, Vasil M Garamus, Christopher J Garvey, Susanne Grünert, Anke Lischka, Annette Meister, Alfred Blume, Bodo Dobner
In the present work, we describe the synthesis and the temperature-dependent aggregation behavior of a new class of asymmetrical glycerol diether bolalipid. These bolalipids are composed of a membrane-spanning alkyl chain with 32 carbon atoms (C32) in the sn-3 position, a methyl-branched C16 alkyl chain in the sn-2 position, and a zwitterionic phosphocholine headgroup in the sn-1 position of a glycerol moiety. The long C32 alkyl chain is terminated either by a second phos-phocholine (PC-Gly(2C16Me)C32-PC) or by a phosphodimethylethanolamine headgroup (PC-Gly(2C16Me)C32-Me2PE)...
March 20, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Shirin Heidari, Mohammad Haghighi, Maryam Shabani
Bi2 Sn2 O7 -C3 N4 /Y nanophotocatalyst with various ratios of zeolite and high activity under simulated solar light irradiation were successfully synthesized using ultrasound-assisted dispersion method. The effect of different amounts of zeolite (10, 20 and 30 wt%) on the photocatalytic degradation of antibiotic tetracycline was investigated. The as-prepared nanophotocatalysts were characterized by XRD, FESEM, EDX, BET, FTIR, DRS and pHpzc techniques. The degradation results demonstrated that, Bi2 Sn2 O7 -C3 N4 /Y(10) nanophotocatalyst with a degradation efficiency of about 80...
May 2018: Ultrasonics Sonochemistry
Tibor Gyori, Balazs Olasz, Gabor Paragi, Gabor Czako
Accuracy of the different levels of electronic structure theory is frequently studied for stationary-point properties, however, little is known about the effects of the electronic structure methods and basis sets on the dynamics of chemical reactions. Here we report such an investigation for the F- + CH3 I SN 2 and proton-transfer reactions by developing 20 different analytical potential energy surfaces (PESs) obtained at the HF/DZ, HF/TZ, HF-D3(BJ)/DZ, HF-D3(BJ)/TZ, MP2/DZ, MP2/TZ, MP2-F12/DZ, MP2-F12/TZ, CCSD/DZ, CCSD-F12b/DZ, CCSD(T)/DZ, CCSD(T)-F12b/DZ, OQVCCD(T)/DZ, B97-1/TZ, PBE0/TZ, PBE0-D3(BJ)/TZ, M06-2X/TZ, M06-2X-D3(0)/TZ, B2PLYP/TZ, and B2PLYP-D3(BJ)/TZ levels of theory, where DZ and TZ denote the aug-cc-pVDZ and aug-cc-pVTZ basis sets with a relativistic effective core potential and the corresponding bases for iodine...
March 16, 2018: Journal of Physical Chemistry. A
Ke Xie, Suowei Wu, Ziwen Li, Yan Zhou, Danfeng Zhang, Zhenying Dong, Xueli An, Taotao Zhu, Simiao Zhang, Shuangshuang Liu, Jinping Li, Xiangyuan Wan
Map-based cloning of maize ms33 gene showed that ZmMs33 encodes a sn-2 glycerol-3-phosphate acyltransferase, the ortholog of rice OsGPAT3, and it is essential for male fertility in maize. Genetic male sterility has been widely studied for its biological significance and commercial value in hybrid seed production. Although many male-sterile mutants have been identified in maize (Zea mays L.), it is likely that most genes that cause male sterility are unknown. Here, we report a recessive genetic male-sterile mutant, male sterility33 (ms33), which displays small, pale yellow anthers, and complete male sterility...
March 15, 2018: TAG. Theoretical and Applied Genetics. Theoretische und Angewandte Genetik
Duong Tung Pham, Joseph Paul Baboo, Jinju Song, Sungjin Kim, Jeonggeun Jo, Vinod Mathew, Muhammad Hilmy Alfaruqi, Balaji Sambandam, Jaekook Kim
Pyrite (FeS2 ) is a promising electrode material for lithium ion batteries (LIBs) because of its high natural availability, low toxicity, cost-effectiveness, high theoretical capacity (894 mA h g-1 ) and high theoretical specific energy density (1270 W h kg-1 , 4e- /FeS2 ). Nevertheless, the use of FeS2 in electrochemical capacitors was restricted due to fast capacity fading as a result of polysulfide (S/Sn 2- ) formation during the initial electrochemical cycling. In order to avoid the formation of polysulfides, we employed the strategy of utilizing an ether based electrolyte (1...
March 15, 2018: Nanoscale
Yu Haranosono, Hiroki Ueoka, Gakushi Kito, Shingo Nemoto, Masaaki Kurata, Hideyuki Sakaki
Most of the α-halo carbonyl (AHC) compounds tend to be predicted as mutagenic by structure-activity relationship based on structural category only, because they have an alkyl halide structure as a structural alert of mutagenicity. However, some AHC compounds are not mutagenic. We hypothesized that AHC reacts with DNA by SN 2 reaction, and the reactivity relates to mutagenicity. As an index of SN 2 reactivity, we focused on molecular orbitals (MOs), as the direction and position of two molecules in collision are important in the SN 2 reaction...
2018: Journal of Toxicological Sciences
Takashi Baba, J Larry Campbell, J C Yves Le Blanc, Paul R S Baker, Kazutaka Ikeda
We report a method for comprehensive structural characterization of lipids in animal tissues using a combination of differential Ion mobility spectrometry (DMS) with electron-impact excitation of ions from organics (EIEIO) mass spectrometry. Singly charged lipid ions in protonated or sodiated forms were dissociated by an electron beam having a kinetic energy of 10 eV in a branched radio-frequency ion trap. We established a comprehensive set of diagnostics to characterize structures of glycerophospholipids, sphingolipids, and acylglycerols, including glycosylated, plasmalogen, and ester forms...
March 14, 2018: Journal of Lipid Research
Christopher M Jenkins, Kui Yang, Gaoyuan Liu, Sung Ho Moon, Beverly G Dilthey, Richard W Gross
Plasmalogens are phospholipids critical for cell function and signaling that contain a vinyl-ether linkage at the   sn -1 position and are highly enriched in arachidonic acid (AA) at the sn -2 position. However, the enzyme(s) responsible for the cleavage of the vinyl ether linkage in plasmalogens has remained elusive.  Herein, we report that cytochrome c , in the presence of either cardiolipin (CL), O2 and H2 O2 , or oxidized CL and O2 , catalyzes the oxidation of the plasmalogen vinyl ether linkage, promoting its hydrolytic cleavage and resultant production of 2-AA-lysolipids and highly reactive α-hydroxy fatty aldehydes...
March 12, 2018: Journal of Biological Chemistry
Benedetta Righino, Angelo Minucci, Davide Pirolli, Ettore Capoluongo, Giorgio Conti, Daniele De Luca, Maria Cristina De Rosa
Phospholipase A2-IIA catalyzes the hydrolysis of the sn-2 ester of glycerophospholipids. A rare c.428G > A (p.Arg143His) variant in PLA2G2A gene was found in two infants affected by acute respiratory distress syndrome (ARDS) by whole coding region and exon/intron boundaries sequencing. To obtain insights into the possible molecular effects of the rare R123H mutation in secretory PLA2-IIA (sPLA2-IIA), molecular modelling, molecular dynamics (MD) using principal component analysis (PCA) and continuum electrostatic calculations were conducted on the crystal structure of the wild type protein and on a generated model structure of the R123H mutant...
March 6, 2018: Journal of Molecular Graphics & Modelling
Teemu Niemi, Israel Fernández, Bethany Steadman, Jere K Mannisto, Timo Repo
We report herein a straightforward general method for the synthesis of cyclic carbamates from amino alcohols and carbon dioxide in the presence of an external base and a hydroxyl group activating reagent. Utilizing p-toluenesulfonyl chloride (TsCl), the reaction proceeds under mild conditions, and the approach is fully applicable to the preparation of various high value-added 5- and 6-membered rings as well as bicyclic fused ring carbamates. DFT calculations and experimental results indicate a SN 2-type reaction mechanism with high regio-, chemo-, and stereoselectivity...
March 12, 2018: Chemical Communications: Chem Comm
Ce Qi, Jin Sun, Yuan Xia, Renqiang Yu, Wei Wei, Jingying Xiang, Qingzhe Jin, Hang Xiao, Xingguo Wang
Fatty acid (FA) is the major energy resource in breast milk, which is important for infant development. FAs profiles with sn-2 positional preference were an important part of triacylglycerols due to their better availability. This profile is still not replicated in artificial formulas. This study quantified the FAs profile of total and sn-2 position in human breast milk samples from 103 healthy volunteers during colostrum, transitional, and mature stages. Multicomponent analysis showed significant differences in FAs profiles of different lactation periods, due to that with relative percentage less than 1%...
March 15, 2018: Journal of Agricultural and Food Chemistry
Márcia Cristina Fernandes Messias, Giovana Colozza Mecatti, Denise Gonçalves Priolli, Patrícia de Oliveira Carvalho
The plasmalogens are a class of glycerophospholipids which contain a vinyl-ether and an ester bond at the sn-1 and sn-2 positions, respectively, in the glycerol backbone. They constitute 10 mol% of the total mass of phospholipids in humans, mainly as membrane structure components. Plasmalogens are important for the organization and stability of lipid raft microdomains and cholesterol-rich membrane regions involved in cellular signaling. In addition to their structural roles, a subset of ether lipids are thought to function as endogenous antioxidants and emerging studies suggest that they are involved in cell differentiation and signaling pathways...
March 7, 2018: Lipids in Health and Disease
Ryan Craig, Emiliano Sorrentino, Stephen J Connon
A new bifunctional phase-transfer catalyst that employs hydrogen bonding as a control element was developed to promote efficient enantioselective SN 2 reactions for the construction all-carbon quaternary stereocenters in high yield and excellent enantioselectivity (up to 97 % ee) utilizing the alkylation of a malleable oxindole substrate. The utility of the methodology was demonstrated through a concise and highly enantioselective synthesis of (-)-debromoflustramine B.
March 7, 2018: Chemistry: a European Journal
Yin-Jen Lu, Yen-Hsun Lai, You-Yu Lin, Yi-Chi Wang, Pi-Hui Liang
This study examines the utility of the N-benzylcarbamoyl (BnCar) protecting group in glycosylation reactions of the parent O-2 protected carbohydrate donor. It was found that the BnCar group imparted exclusively β-selectivity with primary and secondary alcohols. A mechanistic study revealed the activated intermediate to be the glycosyl triflate in a skew conformation, which results in β-selective glycosylation via an SN 2-like pathway. The BnCar group can be readily cleaved using tetrabutylammonium nitrite, without affecting ester and ether protecting groups...
March 7, 2018: Journal of Organic Chemistry
Pedro Araujo, Ephrem Tilahun, Yingxu Zeng
A novel strategy for discriminating genuine and adulterated marine oils is proposed. The strategy consists of i) determining the stereospecific distribution (sn-1, sn-2 and sn-3) of omega 3 polyunsaturated fatty acids (ω-3 PUFA) on the backbone of triacylglycerols by using liquid chromatography tandem mass spectrometry; ii) transforming the qualitative stereospecific information into quantitative data by means of a novel strategy; iii) analyzing the transformed data by principal component analysis. The proposed strategy was tested on pure oils (seal, salmon, cod liver, sandeel, blue whiting, herring), a mixture of blue whiting, herring, sandeel and Norway pout and some intentionally adulterated oils...
May 15, 2018: Talanta
Liang Jie, Ce Qi, Jin Sun, Renqiang Yu, Xiangyu Wang, Sameh A Korma, Jingying Xiang, Qingzhe Jin, Casimir C Akoh, Hang Xiao, Xingguo Wang
Breast milk consumption reduces the incidence of necrotizing enterocolitis (NEC) in preterm infants compared to formula. Branched-chain fatty acids (BCFAs) are present in breast milk but not in most formulas intended for preterm infants. We aimed to determine the composition of BCFAs in the breast milk of mothers with preterm infants, and to understand the impact of gestational age at birth and stage of lactation on BCFA content. The main BCFAs in preterm breast milk were iso-14:0, iso-15:0, anteiso-15:0, iso-16:0, iso-17:0, and anteiso-17:0...
March 2, 2018: Food & Function
Shuanglian Cai, Yangyang Kong, Dan Xiao, Yun Chen, Qiuan Wang
A series of primary aminomethyl derivatives of kaempferol were synthesized by a combination strategy involving two steps of the Mannich reaction and SN 2 nucleophilic substitution. The structures of the products show that the preferential aminomethylations are in the position C-6 or C-8 of the A-ring of kaempferol, especially the latter. Interestingly, the experimental data indicate that the intermolecular hydrogen bonding plays a key role in the formation of primary aminomethyl products of kaempferol. The formation of appropriate hydrogen bonds between strong nucleophilic amino acids and phenol is essential for the smooth reaction of the SN 2 nucleophilic substitution...
February 28, 2018: Organic & Biomolecular Chemistry
Cong Sun, Wei Wei, Xiaoqiang Zou, Jianhua Huang, Qingzhe Jin, Xingguo Wang
Triacylglycerol (TAG) composition in 180 commercial infant, follow-on and growing-up formulas with different fat sources (plant oil, cow's milk and goat's milk) were analyzed and compared with mature human milk (MHM). TAGs in formulas were greatly affected by fat source. Formulas contained higher proportions of TAGs with short-chain/medium-chain saturated fatty acids, OOO and acyl carbon number (ACN) 54, and lower proportions of ACN 52 than MHM. There were significant differences in the content and stereochemical structure of OPL and OPO between formulas and MHM...
June 30, 2018: Food Chemistry
Giovanna Trinchese, Gina Cavaliere, Chiara De Filippo, Serena Aceto, Marina Prisco, Jong Tai Chun, Eduardo Penna, Rossella Negri, Laura Muredda, Andrea Demurtas, Sebastiano Banni, Roberto Berni-Canani, Giuseppina Mattace Raso, Antonio Calignano, Rosaria Meli, Luigi Greco, Marianna Crispino, Maria P Mollica
Scope: Milk from various species differs in nutrient composition. In particular, human milk (HM) and donkey milk (DM) are characterized by a relative high level of triacylglycerol enriched in palmitic acid in sn-2 position. These dietary fats seem to exert beneficial nutritional properties through N-acylethanolamine tissue modulation. The aim of this study is to compare the effects of cow milk (CM), DM, and HM on inflammation and glucose and lipid metabolism, focusing on mitochondrial function, efficiency, and dynamics in skeletal muscle, which is the major determinant of resting metabolic rate...
2018: Frontiers in Physiology
Morteza Bahrami, Ahmad Homaei
Papain has a relatively small active site consisting of three residues: Cys-25, His-159, and Asn-175. The sulfhydryl group on Cys-25 often forms covalent bonds with substrates. His-159 supports Cys-25, and while Asn-175 does not directly participate in the catalytic mechanism, it keeps histidine-159 in its stabilized imidazole form. It is noticeable that sulfur atom of the catalytic Cys-25 is activated by cysteine through a SN 2-type reaction, but the mechanisms by which cysteine enhances papain activity remains unclear...
February 15, 2018: International Journal of Biological Macromolecules
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"