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71.
Alina Iacob 《代数通讯》2017,45(5):2238-2244
We prove that the class of Gorenstein injective modules is both enveloping and covering over a two sided noetherian ring such that the character modules of Gorenstein injective modules are Gorenstein flat. In the second part of the paper we consider the connection between the Gorenstein injective modules and the strongly cotorsion modules. We prove that when the ring R is commutative noetherian of finite Krull dimension, the class of Gorenstein injective modules coincides with that of strongly cotorsion modules if and only if the ring R is in fact Gorenstein. 相似文献
72.
Chondroitin/dermatan sulfate (CS/DS) chain of decorin (DCN) from human skin fibroblasts (HSk) was released by reductive β-elimination reaction and digested with chondroitin AC I lyase. Enzymatic hydrolysis mixture of CS/DS chains was separated by size-exclusion chromatography (SEC). Collected octasaccharide fraction was subjected to fully automated chip-based nanoelectrospray (nanoESI) quadrupole time-of-flight (QTOF) MS and tandem MS (MS/MS). MS of human skin fibroblasts DCN CS/DS displayed a high complexity due to the large variety of glycoforms, which under chip-nanoESI MS readily ionized to form multiply charged ions. Except for the regularly tetrasulfated octasaccharide, the investigated fraction contained four additional octasaccharides of atypical sulfation status. Two new oversulfated glycoforms and two undersulfated species were identified. Remarkably, the series of decasaccharides discovered in the same SEC pool was found to encompass a trisulfated and a novel hexasulfated [4,5-Δ-GlcAGalNAc(IdoAGalNAc)?] species. MS/MS by collision-induced dissociation (CID) on the [M-4H]? ion corresponding to the previously not reported [4,5-Δ-GlcAGalNAc(IdoAGalNAc)?](5S) corroborated for a novel motif in which three N-acetylgalactosamine (GalNAc) moieties are monosulfated, 4,5-Δ-GlcA and the first IdoA from the non-reducing end bear one sulfate group each, while the second N-acetylgalactosamine from the reducing end is unsulfated. 相似文献
73.
Losego MD Guske JT Efremenko A Maria JP Franzen S 《Langmuir : the ACS journal of surfaces and colloids》2011,27(19):11883-11888
Self-assembled monolayers (SAMs) of alkanephosphonic acids with chain lengths between 8 and 18 carbon units were formed on thin films of indium tin oxide (ITO) sputter-deposited on silicon substrates with 400 nm thermally grown SiO(2). The silicon substrates, while not intended for use in near-IR or visible optics applications, do provide smooth surfaces that permit systematic engineering of grain size and surface roughness as a function of the sputter pressure. Argon sputter pressures from 4 to 20 mTorr show systematic changes in surface morphology ranging from smooth, micrometer-sized grain structures to <50 nm grains with 3× higher surface roughness. Near-edge X-ray absorption fine structure (NEXAFS) spectroscopy experiments are conducted for alkanephosphonic acids deposited on these wide range of ITO surfaces to evaluate the effects of these morphological features on monolayer ordering. Results indicate that long-chain SAMs are more highly ordered, and have a smaller tilt angle, than short-chain SAMs. Surprisingly, the 1-octadecyl phosphonic acids maintain their order as the lateral grain dimensions of the ITO surface shrink to ~50 nm. It is only when the ITO surface roughness becomes greater than the SAM chain length (~15 ?) that SAMs are observed to become relatively disordered. 相似文献
74.
Iaroshenko VO Bunescu A Spannenberg A Supe L Milyutina M Langer P 《Organic & biomolecular chemistry》2011,9(21):7554-7558
The reaction of 1,3-bis-silyl enol ethers with 3-methoxalylchromones affords a great variety of functionalised 2,4'-dihydroxybenzophenones. These products are formed by a domino Michael/retro-Michael/Mukaiyama-aldol reaction. The synthesized compounds are promising candidates for the synthesis of the novel UV-A/B and UV-B filters. 相似文献
75.
Sergeeva AP Averkiev BB Zhai HJ Boldyrev AI Wang LS 《The Journal of chemical physics》2011,134(22):224304
We have investigated the structural and electronic properties of the B(17)(-) and B(18)(-) clusters using photoelectron spectroscopy (PES) and ab initio calculations. The adiabatic electron detachment energies of B(17)(-) and B(18)(-) are measured to be 4.23 ± 0.02 and 3.53 ± 0.05 eV, respectively. Calculated electron detachment energies are compared with experimental data, confirming the presence of one planar C(2v) ((1)A(1)) isomer for B(17)(-) and two nearly isoenergetic quasi-planar C(3v) ((2)A(1)) and C(s) ((2)A') isomers for B(18)(-). The stability and planarity/quasi-planarity of B(17)(-) and B(18)(-) are ascribed to σ- and π-aromaticity. Chemical bonding analyses reveal that the nature of π-bonding in B(17)(-) and B(18)(-) is similar to that in the recently elucidated B(16)(2-) and B(19)(-) clusters, respectively. The planar B(17)(-) cluster can be considered as an all-boron analogue of naphthalene, whereas the π-bonding in the quasi-planar B(18)(-) is reminiscent of that in coronene. 相似文献
76.
Agata Górniak Alina Wojakowska Bożena Karolewicz Janusz Pluta 《Journal of Thermal Analysis and Calorimetry》2011,104(3):1195-1200
Enhancement of the dissolution rate of poorly soluble compounds through the formation of drug–drug eutectics was investigated
using fenofibrate and acetylsalicylic acid. Solid–liquid equilibria in the system under study were investigated by differential
scanning calorimetry (DSC). The phase diagram for the whole range of compositions was constructed. In addition, existence
of a metastable polymorph of fenofibrate has been confirmed. The investigation has revealed that acetylsalicylic acid and
fenofibrate form a simple eutectic mixture containing 0.958 mol fraction of fenofibrate at the eutectic point. Dissolution
rate improvement of fenofibrate correlated with the phase diagram. The amount of fenofibrate released from the solid dispersions
that contained fenofibrate as the eutectic mixture with acetylsalicylic acid was at least threefold higher compared to untreated
fenofibrate. 相似文献
77.
Nowicka Beata Burgess John Parsons Simon A. Samotus Alina Szklarzewicz Janusz 《Transition Metal Chemistry》1998,23(3):317-319
Solvatochromism of the [Mo(CN)3O(phen)]− ion has been studied. Solvent effects on pressure dependence (up to 1.25 kbar) of wavelengths of maximum absorption for charge-transfer
bands of several molybdenum(IV) and tungsten(IV) complexes, [M(CN)3O(diimine)]− (M = Mo or W), are described. The effects of applied pressure are larger for less polar unstructured solvents than for highly
polar hydrogen-bonded solvents.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
78.
JPC – Journal of Planar Chromatography – Modern TLC - Nicotinic acid (NAC) and its derivatives methyl nicotinate (MN), ethyl nicotinate (EN), isopropyl nicotinate (IPN), butyl... 相似文献
79.
Ming Sun Alina Stetco Erika F Merschrod S 《Langmuir : the ACS journal of surfaces and colloids》2008,24(10):5418-5421
Ordered arrays of collagen microfibrils form rapidly and spontaneously from a solution of monomers deposited onto a mica substrate. These arrays are well-ordered and apparently continuous over the entire substrate. Correlated atomic force microscope images and Laué diffraction patterns indicate that the protein alignment and microfibril formation is controlled by the crystal orientation of the mica substrate rather than fluid flow or drying effects. This surface-induced mechanism allows for immediate, robust, and reproducible pattern formation. 相似文献
80.
Staśkowiak E Dudkowiak A 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2005,61(9):2033-2039
The paper deals with some fast and slow processes of excitation energy deactivation in bacteriochlorophyll c and bacteriopheophytin c. The experiments were carried out in the air, and in oxygen or nitrogen atmosphere at different temperatures. The parameters such as fluorescence yield, the yield of triplet state generation and photostability were estimated. On the basis of these parameters an attempt was made to preliminary select the pigments best suited for medical applications. It seems that the photosensitive and highly fluorescent bacteriochlorophyll c could be used as a fluorescence probe for diagnosis, whereas its derivative without the magnesium ion is better suited for the photochemical reactions occurring during therapeutic treatment. 相似文献