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961.
Fengzhao Yang Zhancheng Xu Jinjie Wang Feng Zan Chaoqing Dong Jicun Ren 《Luminescence》2013,28(3):392-400
In this study, we report for the first time a one‐pot approach for the synthesis of new CdSeTeS quaternary‐alloyed quantum dots (QDs) in aqueous phase by microwave irradiation. CdCl2 was used as a Cd precursor during synthesis, NaHTe and NaHSe were used as Te and Se precursors and mercaptopropionic acid (MPA) was used as a stabilizer and source of sulfur. A series of quaternary‐alloyed QDs of different sizes were prepared. CdSeTeS QDs exhibited a wide emission range from 549 to 709 nm and high quantum yield (QY) up to 57.7 %. Most importantly, the quaternary‐alloyed QDs possessed significantly long fluorescence lifetimes > 100 ns as well as excellent photostability. Results of high‐resolution transmission electron microscopy (HRTEM), energy dispersive X‐ray spectroscopy (EDX) and powder X‐ray diffraction (XRD) spectroscopy showed that the nanocrystals possessed a quaternary alloy structure with good crystallinity. Fluorescence correlation spectroscopy (FCS) showed that QDs possessed good water solubility and monodispersity in aqueous solution. Furthermore, CdSeTeS QDs were modified with alpha‐thio‐omega‐carboxy poly(ethylene glycol) (HS‐PEG‐COOH) and the modified QDs were linked to anti‐epidermal growth factor receptor (EGFR) antibodies. QDs with the EGFR antibodies as labeling probes were successfully applied to targeted imaging for EGFR on the surface of SiHa cervical cancer cells. We believe that CdSeTeS QDs can become useful probes for in vivo targeted imaging and clinical diagnosis. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
962.
Wei Chen Michael T. Flavin Robert Filler Ze-Qi Xu 《Nucleosides, nucleotides & nucleic acids》2013,32(11-12):1771-1778
Abstract Unprotected adenine, 6-chloropurine, 2.6-diaminopurine. and 2-amino-6-chluropurine have been directly coupled with 2-(diethoxyphosphonomethoxy)ethanol under Mitsunobu reaction conditions to provide acyclic phosphonate nucleotide analogues which are intermediates for antiviral agents such as PMEA. 相似文献
963.
Zai-Wan Yang Zu-Sheng Xu Nan-Zhen Shen Zhi-Qiang Fang 《Nucleosides, nucleotides & nucleic acids》2013,32(1-2):167-173
Abstract In the present paper we describe the preparation of a novel crystalline phosphonylating agent 9-fluorenemethyl phosphonic acid 2 and a convenient and efficient method for the synthesis of nucleoside H-phosphonates 5. 相似文献
964.
Novel hybrid SiO2‐coated CdTe quantum dots (QDs) were created using CdTe QDs coated with a hybrid SiO2 shell containing Cd2+ ions and a sulfur source via a sol–gel process in aqueous solution. Aqueous CdTe QDs with tunable emitting color created through a reaction between cadmium chloride and sodium hydrogen telluride was used as cores for the preparation of hybrid SiO2‐coated CdTe QDs. In our experiments we found that the surface state of the cores and preparation conditions that affect the formation of the hybrid SiO2 shell also greatly affect photoluminescence of the hybrid SiO2‐coated CdTe QDs. The generation of CdS‐like clusters in the vicinity of the CdTe QDs, caused the quantum size effect of the QDs to be greatly reduced, which changes photoluminescence properties of the hybrid QDs fundamentally. Namely, the novel hybrid SiO2 shell played an important role in generating a series of specific optical properties. In addition, the novel hybrid SiO2 shell can be created if no CdTe QD is added. In order to gain an insight into the inter structure of the hybrid shell, we characterized the hybrid SiO2‐coated CdTe QDs using X‐ray diffraction analysis and discuss the formation mechanism of such a hybrid structure. This work is significant because the novel hybrid SiO2‐coated CdTe QDs with its excellent properties can be used in many applications, such as biolabeling and optoelectronic devices. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
965.
Dongling Xu Xingming Wang Dan Fei Lisheng Ding 《Nucleosides, nucleotides & nucleic acids》2013,32(11-12):854-866
Ultraviolet-visible (UV-vis) spectra, fluorescence spectra, electrochemistry, and the thermodynamic method were used to discuss the interaction mode between the inclusion complex of hematoxylin with β-cyclodextrin and herring sperm DNA. On the condition of physiological pH, the result showed that hematoxylin and β-cyclodextrin formed an inclusion complex with binding ratio nhematoxylin:nβ-cyclodextrin = 1:1. The interaction mode between β-cyclodextrin-hematoxylin and DNA was a mixed binding, which contained intercalation and electrostatic mode. The binding ratio between β-cyclodextrin-hematoxylin and DNA was nβ-cyclodextrin -hematoxylin:nDNA = 2:1, binding constant was K? 298.15K = 5.29 × 104 L·mol?1, and entropy worked as driven force in this action. 相似文献
966.
Di Zhang Yamin Li Liang Xu Maosheng Cheng Ying Zhou Junlin He 《Nucleosides, nucleotides & nucleic acids》2013,32(10):734-747
Tert-butyldiphenylsilyl (TBDPS) was testified to be an appropriate orthogonal protecting group for novel 7-hydroxyl-functionalized 8-aza-7-deaza-2′-deoxyadenosine analogues. It was stable in partial and complete hydrogenation reactions used for the different linker preparation. The corresponding phosphoramidites and hydroxyl-functionalized oligodeoxynucleotides were synthesized and identified. The thermal effect of the hydroxyl group with different linkers on DNA duplexes was evaluated. It provided a feasible strategy for the preparation of hydroxyl-functionalized DNAs for the nucleic acid research. 相似文献
967.
Cre/LoxP‐mediated recombination allows for conditional gene activation or inactivation. When combined with an independent lineage‐tracing reporter allele, this technique traces the lineage of presumptive genetically modified Cre‐expressing cells. Several studies have suggested that floxed alleles have differential sensitivities to Cre‐mediated recombination, which raises concerns regarding utilization of Cre‐reporters to monitor recombination of other floxed loci of interest. Here, we directly investigate the recombination correlation, at cellular resolution, between several floxed alleles induced by Cre‐expressing mouse lines. The recombination correlation between different reporter alleles varied greatly in otherwise genetically identical cell types. The chromosomal location of floxed alleles, distance between LoxP sites, sequences flanking the LoxP sites, and the level of Cre activity per cell all likely contribute to observed variations in recombination correlation. These findings directly demonstrate that, due to non‐parallel recombination events, commonly available Cre reporter mice cannot be reliably utilized, in all cases, to trace cells that have DNA recombination in independent‐target floxed alleles, and that careful validation of recombination correlations are required for proper interpretation of studies designed to trace the lineage of genetically modified populations, especially in mosaic situations. genesis 51:436–442. © 2013 Wiley Periodicals, Inc. 相似文献
968.
Shuying Yang Yi‐Ping Li Tongjun Liu Xiaoning He Xue Yuan Chunyi Li Jay Cao Yunjung Kim 《Genesis (New York, N.Y. : 2000)》2013,51(3):201-209
Regulators of G‐protein Signaling (Rgs) proteins are the members of a multigene family of GTPase‐accelerating proteins (GAP) for the Galpha subunit of heterotrimeric G‐proteins. Rgs proteins play critical roles in the regulation of G protein couple receptor (GPCR) signaling in normal physiology and human diseases such as cancer, heart diseases, and inflammation. Rgs12 is the largest protein of the Rgs protein family. Some in vitro studies have demonstrated that Rgs12 plays a critical role in regulating cell differentiation and migration; however its function and mechanism in vivo is largely unknown. Here, we generated a floxed Rgs12 allele (Rgs12flox/flox) in which the exon 2, containing both PDZ and PTB_PID domains of Rgs12, was flanked with two loxp sites. By using the inducible Mx1‐cre and Poly I:C system to specifically delete Rgs12 at postnatal 10 days in interferon‐responsive cells including monocyte and macrophage cells, we found that Rgs12 mutant mice had growth retardation with the phenotype of increased bone mass. We further found that deletion of Rgs12 reduced osteoclast numbers and had no significant effect on osteoblast formation. Thus, Rgs12flox/flox conditional mice provide a valuable tool for in vivo analysis of Rgs12 function and mechanism through time‐ and cell‐specific deletion of Rgs12. genesis 51:201–209, 2013. © 2013 Wiley Periodicals, Inc. 相似文献
969.
X. Xu L. Zhao X. Hu P. Zhang J. Wessale R. Bache 《Nucleosides, nucleotides & nucleic acids》2013,32(4-6):306-313
The nonpurine selective xanthine oxidase (XO) inhibitor febuxostat attenuates development of left ventricular (LV) hypertrophy and dysfunction in mice when treatment is initiated within 1 hour of transverse aortic constriction (TAC). This study investigated whether a 7-day delay of treatment with the XO inhibitors febuxostat or allopurinol would reverse TAC-induced changes after onset of heart failure (HF). Neither treatment significantly affected TAC-induced LV hypertrophy; only febuxostat caused a modest improvement in LV function (~10% increase in LV ejection fraction). However, the purine analog allopurinol tended to increase mortality compared with vehicle or febuxostat in HF mice. 相似文献
970.