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961.
Tomislav Došlić 《Journal of mathematical chemistry》2007,41(3):217-229
A global forcing set in a simple connected graph G with a perfect matching is any subset S of E(G) such that the restriction of the characteristic function of perfect matchings of G on S is an injection. The number of edges in a global forcing set of the smallest cardinality is called the global forcing number
of G. In this paper we prove several results concerning global forcing sets and numbers of benzenoid graphs. In particular, we
prove that all catacondensed benzenoids and catafused coronoids with n hexagons have the global forcing number equal to n, and that for pericondensed benzenoids the global forcing number is always strictly smaller than the number of hexagons. 相似文献
962.
Antonilêni F. D. Medeiros Ana Flávia O. Santos F. S. de Souza I. D. B. Júnior J. Valdilânio J. V. V. Procópio D. P. de Santana R. O. Macêdo 《Journal of Thermal Analysis and Calorimetry》2007,89(3):775-781
Compatibility studies between active drugs and excipients are substantial in the pharmaceutical technology. The objective
of the present work was to develop pre-formulated mixtures of metronidazole (MT) obtained by spray drying (SPDR) and their
thermoanalytical characterization. Dynamic and isothermal TG, conventional DSC and DSC coupled to a photovisual system were
used. DSC experiments with both techniques confirmed the homogeneity of the conventional and pre-formulated mixtures. The
TG data made possible the comparison the thermal stability of the different mixtures. Similar thermal stabilities were found
of the conventional and pre-formulated mixtures, with slower particles sizes of MT. 相似文献
963.
964.
Herng-Show Chang Show-An Chen 《Journal of polymer science. Part A, Polymer chemistry》1988,26(4):1207-1229
The emulsifier-free emulsion polymerizations of styrene in the presence of about 1 wt% (related to styrene) of the water soluble comonomer, sodium methallyl sulfonate (NaMS), which has short hydrophobic group and strong hydrophilic ionic group, and of the initiator, potassium persulfate, are carried out. Under constant ionic strength, the number density of polymer particles (Np) is found to depend on 0.5-power of the initiator concentration and shows a minimum in the comonomer concentration plot. Under constant concentration of monomer, comonomer and initiator, Np is found to depend on ?1.1-power of the ionic strength. In the earlier period, the presence of styrene oligomer having MW about 1000 and water soluble poly(NaMS) or copolymer with high NaMS content suggests a micellar nucleation mechanism, by which the styrene oligomer behaves as emulsifier and the poly(NaMS) can either stabilize or destabilize the existing particles, depending on its concentration in the aqueous phase. The particle size is rather uniform having an uniformity very close to 1 (ca. 1.001) throughout the entire process. It is much larger than that of the conventional emulsion polymerization or emulsifier-free emulsion polymerization with the other comonomers by about 3 to 4 times in diameter or 27 to 64 times in volume, leading to that the average radical number in the particle could be much greater than 0.5. The (conversion)2/3 versus time plot is found to be linear from 6 to 50% conversion. During this period, for the conversion from 10 to 40% the polymerization rate increases twice but the particle volume increases four-fold. In addition, MWD shows bimodal (excluding the styrene oligomer peak in the earlier period) during the growth period. But the lower MW peak shifts to higher MW and become larger, while the higher MW peak decreases, and finally the MWD becomes single mode after 58.6% conversion. These results suggest a “gradient polymerization” or “transition stage to core-shell structure” in the earlier stage of particle growth and a “shell part polymerization” in the later stage. 相似文献
965.
Min Gyu Jeong Kai Zhou Soyeon Park HyeongJeon An Yonghoon Kwon Yeonho Chang Do-Hyeon Kim Sung Ho Ryu 《Experimental & molecular medicine》2021,53(2):291
Various repertoires of membrane protein interactions determine cellular responses to diverse environments around cells dynamically in space and time. Current assays, however, have limitations in unraveling these interactions in the physiological states in a living cell due to the lack of capability to probe the transient nature of these interactions on the crowded membrane. Here, we present a simple and robust assay that enables the investigation of transient protein interactions in living cells by using the single-molecule diffusional mobility shift assay (smDIMSA). Utilizing smDIMSA, we uncovered the interaction profile of EGFR with various membrane proteins and demonstrated the promiscuity of these interactions depending on the cancer cell line. The transient interaction profile obtained by smDIMSA will provide critical information to comprehend the crosstalk among various receptors on the plasma membrane.Subject terms: Fluorescence imaging, Super-resolution microscopy, Single-molecule biophysics 相似文献
966.
Sham M. Sondhi Shefali Rajvanshi Nirupma Singh Shubhi Jain Anand M. Lahoti 《Central European Journal of Chemistry》2004,2(1):141-187
Non steroidal anti-inflammatory drugs are the most widely used medicines for relief of pain. These drugs have some side effects,
particularly toxicity in the gastrointestinal tract and kidneys. Various approaches have been used for obtaining safer anti-inflammatory
drugs. In this review we have summarized the recent developments in the following areas; (i) mode of action of NSAIDs (ii)
Role of COX-1 & COX-2 in inflammation, (iii) Different approaches used to improve gastric tolerance i.e. chemical manipulation,
formulation & co-administration, development of non specific (COX-1 & COX-2 inhibitors) and specific (COX-2 inhibitors) inflammation
inhibitors, and development of inflammation inhibitors having a mode of action other than COX-1 & COX-2 inhibition. We have
also focused on the safety of COX-2 inhibitors and the synthesis of heterocyclic compounds and their role as inflammation
inhibitors. 相似文献
967.
An efficient cobalt-catalyzed carbocylization for the synthesis of indenols and indenes and a new method for reductive decyanation are described. 2-Iodophenyl ketones and aldehydes 1a-g undergo carbocyclization with various disubstituted alkynes 2a-k in the presence of Co(dppe)I(2) and zinc powder in acetonitrile at 80 degrees C for 3 h to afford the corresponding indenol derivatives 3a-s and4a-m in good to excellent yields. For some unsymmetrical alkynes, the carbocyclization was remarkably regioselective, affording a single regioisomer. The cobalt-catalyzed carbocyclization reaction was successfully extended to the synthesis of indene derivatives. Thus, the reaction of 2-iodophenyl ketones and aldehydes (1) with acrylates H(2)C=CHCO(2)R (7a-d) and acrylonitrile H(2)C=CHCN (7e) proceeds smoothly in the presence of Co(dppe)Cl(2)/dppe and zinc powder in acetonitrile at 80 degrees C for 24 h to afford the corresponding indenes 8a-k and 9a-c in moderate to good yields. Interestingly, when 7e was employed for the carbocylization, reductive decyanation also occurred to give an indene derivative without the cyano functionality. A possible mechanism for this cobalt-catalyzed carbocyclization reaction is also proposed. 相似文献
968.
Characterization of amiodarone metabolites and impurities using liquid chromatography/atmospheric pressure chemical ionization mass spectrometry 总被引:1,自引:0,他引:1
Myung SW Chang YJ Min HK Kim DH Kim M Kang TK Yoo EA Sohn YT Yim YH 《Rapid communications in mass spectrometry : RCM》2000,14(21):2046-2054
Using the high performance liquid chromatography/atmospheric pressure chemical ionization tandem mass spectrometry (HPLC/APCI-MS/MS) technique, together with established trends from the literature, the structures of metabolites and impurities of amiodarone, an anti-arrhythmic drug, have been assigned. By comparing analyses of products of incubation with rat liver microsomes with controls in which glucose 6-phosphate dehydrogenase was omitted, metabolites could be distinguished from impurities. Structures for the two proposed metabolites and four impurities are proposed. 相似文献
969.
The goal of the present study is to test the hypothesis that LPA induces proliferation of astrocytes in hippocampus in vivo via phosphorylation of ERK 1/2. We first characterized the expression of GFAP, a special marker fiber protein of astrocytes,
in brain slices after direct injection of LPA into hippocampus by immunohistochemistry, and found that LPA induced a remarkable
proliferation of astrocytes. Then double-lablled immunofluorescence was used to detect GFAP and phosphorylation ERK 1/2 (p-ERK
1/2), LPA induced an immediate (10 min) and transient (<30 min) phosphorylation of ERK 1/2, and sequence sustained activation
of ERK 1/2 was observed, which last for at least 3 weeks after injection of LPA. Reactions are inhibited by U0126, a specific
pharmacological mitogen-activated protein kinase (MEK) inhibitor. Laser confocal scanning was used to study spatial relationship
of p-ERK and astrocytes. Amazingly, the early (<7 days) phosphorylation of ERK 1/2 is not expressed in astrocytes but in area
where neurons and/or in other cell type(s) occupied, expression of p-ERK 1/2 in astrocytes is not detected until 14 days after
LPA injection and lasts for at least 3 weeks. Taken together, these data suggest that LPA play an important role in proliferation
of astrocytes through phosphorylation of ERK 1/2 in hippocampus. It provides further proof for the functions of LPA in CNS
injury, and may contribute to clinical therapy for relative diseases. 相似文献
970.