58 research outputs found
Biological Functionalization of Conjugated Polymer Nanoparticles for Targeted Imaging and Photodynamic Killing of Tumor Cells
Conjugated polymer
nanoparticles composed of PFT/PS as a core and PEG-COOH on the surface
were prepared by a reprecipitating method. The CPNs diaplay excellet
properties such as good photostability, low cytotoxicity, and strong
brightness, etc. The average diamater of CPNs is 30 nm with a spherical
morphology. To realize specific imaging in different parts of tumor
cells, the bare CPNs with the carboxyls on the surface were conjugated
with antibody or peptide by a covalent mode. Studies display that
CPNs modified with anti-EpCAM can recognize MCF-7 tumor cells and
locate on the membrane, while CPNs conjugated with transcriptional
activator protein (Tat) specifically locate in the cytoplasm of MCF-7
cells. On the basis of the ability of CPNs for producing reactive
oxygen species (ROS) under light irradiation, photodynamic therapy
for tumor cells was investigated. Due to the long distance and wide
diffusion range, MCF-7 tumor cells with CPNs/anti-EpCAM have no obvious
change with or without white light irradiation. However, CPNs/Tat
exhibits higher killing ability for MCF-7 cells. Noticeably, multifunctional
CPNs linked with anti-EpCAM and Tat simultaneously not only can specifically
target MCF-7 tumor cells, but also may inhibit and kill these cells.
This work develops a potential application platform for multifunctional
CPNs in locating imaging, photodynamic therapy, and other aspects
Atomistic investigation of homogeneous nucleation in undercooled liquid
<p>Although nucleation, a fundamental physical phenomenon in nature, has long been studied by simulations and experiments, our knowledge of this process is still quite limited. Herein, the atomistic pathways of homogeneous nucleation are studied using the phase-field crystal model. We find that nucleation is of one-step type for low initial densities (solid volume fraction), whereas two-step nucleation (TS) dominates in other cases. For the TS process, the fraction and the lifetime of metastable intermediate phases will increase with increasing density, and these metastable phases can significantly accelerate the nucleation process. By calculating the nucleation barriers, we investigated the origin of the appearance of the metastable phases and the mechanism of two-step nucleation.</p
Knoevenagel reaction promoted by functional ionic liquids with primary and tertiary amines
Functional ionic liquids have been widely used in the fields of synthetic chemistry, analytical chemistry, electrochemistry and material chemistry owing to their excellent properties such as easy structure modification and adjustable properties. In this work, a series of basic functionalized ionic liquids were prepared from 1, 4-diazabicyclo [2.2.2] octane (DABCO) or hexamethylenetetramine (HMTA) with various halogenated hydrocarbons, then these functional ionic liquids and water were used as solvent-catalyst system in the Knoevenagel reaction of various aldehydes with ethyl cyanoacetate or malononitrile, the influence of the structure of the ionic liquid and the content of water was investigated. The results showed that the composite solvent-catalyst system mixed by the functional ionic liquid N-(3-aminopropyl)-1,4-diazabicyclo [2.2.2] octane bromide with water can effectively promote the Knoevenagel reaction and the alkalinity of amine and hydrogen bond play an important role. Aromatic aldehydes with electron-donating or electron-withdrawing groups can obtain the target product at an excellent yield (79-99%). It is worth noting that the polycyclic aromatic aldehydes with high steric hindrance, 86%-95% yields of the object products were also obtained after 15 h-25 h. Furthermore, the catalyst could be reused for 6 times without any loss in its catalytic activity. The composite solvent-catalyst system mixed by the Functional ionic liquid N-(3-aminopropyl)-1,4-diazabicyclo[2.2.2]octane bromide with water can effectively promote the Knoevenagel reaction, even for the electron-rich aromatic aldehydes with poor reactivity, high yields of the target products and fast reaction rate were also obtained at room temperature.</p
Carboniferous appinitic intrusions from the northern North China craton: geochemistry, petrogenesis and tectonic implications
<p>Laser ablation inductively coupled plasma mass spectrometry zircon U–Pb dating and geochemical study document Carboniferous
(<em>c</em>. 320–317 Ma) appinitic intrusions from the northern North China craton. The rock suite mainly consists of hornblende diorites
and monzodiorites, with an SiO<sub>2</sub> range from 46.8 to 55.4%. These rocks exhibit high alkali contents, strong enrichment in large ion lithophile elements and
light rare earth elements, and depletion in high field strength elements, with radiogenic <sup>87</sup>Sr/<sup>86</sup>Sr<sub>i</sub> ratios of 0.7058–0.7093, unradiogenic ϵ<sub>Nd</sub>(t) of −9.3 to −13.9 and zircon ϵ<sub>Hf</sub>(t) from −8.5 to −18.4. These geochemical features suggest that their generation may involve a distinctive two-stage process:
(1) a precursory metasomatism stage of mantle peridotites by melts from subduction-related sediments; (2) a delayed partial
melting stage probably initiated by post-subduction transcurrent movements along pre-existing lithospheric shear zones. These
mafic to intermediate intrusions, plus other coeval mafic– ultramafic complexes and high Ba–Sr granites from neighbouring
regions, not only witness a heterogeneously enriched subcontinental lithospheric mantle along the northern North China craton,
but also attest to a reworking-dominated metacratonic process within a post-subduction transtensional regime.
</p
Novel selenium-containing acenaphtho[1,2-b]pyrrole derivatives: Synthesis and bioactivity
<p>Seven novel selenium-containing acenaphtho[1,2-b]pyrrole derivatives were designed and synthesized and their cytotoxic effects were evaluated by the MTT tetrazolium dye assay. Two compounds presented good anticancer activities.</p
Composite Icosahedron/Cube Endohedral Clusters in Rh<sub>2</sub>Cd<sub>15</sub>
We present Rh<sub>2</sub>Cd<sub>15</sub>, the first binary compound in the Rh–Cd
system. It is based on transition-metal-embedded (Rh@Cd<sub>11</sub> and Rh@Cd<sub>12</sub>) endohedral Cd clusters that are single-
and double-capped IC<sub>10</sub> composite icosahedra/cubes. We demonstrate
the structural connections between the clusters. On the basis of the
analysis of atomic interactions and electron counting, 50 electrons
per Rh<sub>2</sub>Cd<sub>15</sub> is postulated to be the boundary
between bonding and antibonding interactions. This understanding is
supported by electronic structure calculations showing that the electron
count for Rh<sub>2</sub>Cd<sub>15</sub> (48 electrons per Rh<sub>2</sub>Cd<sub>15</sub>) is located close to a deep pseudogap in the electronic
density of states at 50 electrons per formula unit, which we postulate
is an important factor in determining the new compound’s stability
Formation of Ether-Functionalized Ionic-Liquid-Based Aqueous Two-Phase Systems and Their Application in Separation of Protein and Saccharides
Ionic-liquid
(IL)-based aqueous two-phase systems (ATPSs) have
attracted much attention in the separation technology. In this work,
we synthesized five novel ether-functionalized ILs and studied their
applications in ATPS formation. The phase diagrams for several systems
were determined at 298.15 K. An as-prepared IL (1-(2-butoxy-ethyl)-3-methylimidazolium
chloride) was chosen as a representative to construct ATPSs for separation
of bovine serum albumin (BSA) from aqueous saccharide solutions. Results
showed that 76.1–94.3% of BSA was enriched into the IL-rich
top phase and almost all the saccharides were extracted into the salt-rich
bottom phase in a one-step separation process. The main factors affecting
the separation process, such as kinds of saccharides and the amount
of inorganic salts, were discussed. Furthermore, the size distributions
of aggregates in the IL-rich top phase were determined by dynamic
light scattering (DLS), and accordingly the possible mechanism for
the separation was investigated
Banding patterns of pHZ2031 respectively linearized using four different but unique restriction enzymes (EcoRV, EcoRI, XhoI and NdeI) before treatment with activated Tris-buffer
<p><b>Copyright information:</b></p><p>Taken from "DNA modification by sulfur: analysis of the sequence recognition specificity surrounding the modification sites"</p><p></p><p>Nucleic Acids Research 2007;35(9):2944-2954.</p><p>Published online 16 Apr 2007</p><p>PMCID:PMC1888814.</p><p>© 2007 The Author(s)</p> Two fragments adding up to the size of linearized pHZ2031 (5.4 kb) were always seen at their expected positions after cleavage at a common modification site, as exemplified by cleavage at specific modification site 10 (), indicated as two white asterisks in each respective gel panel. (EcoRV: 4182 and 1231; EcoRI: 3027 and 2386; XhoI: 3976 and 1437; NdeI: 4687 and 726)
Design and Control of the Luminescence of Cr<sup>3+</sup>-Doped Phosphors in the Near-Infrared I Region by Fitting the Crystal Field
Red or near-infrared
phosphors, which have a lower absorption in
biological tissue, show excellent promise in the field of bioimaging.
Here, we design the red phosphor with a broad emission band and realize
tunable luminescence of Cr<sup>3+</sup> by two methods, i.e., adjusting
the Cr<sup>3+</sup>-doping concentration in Zn<sub>3</sub>(AlGa)<sub>2</sub>ÂGe<sub>2</sub>O<sub>10</sub> solid solution and doping
In<sup>3+</sup> ions in Zn<sub>3</sub>Al<sub>2</sub>Ge<sub>2</sub>O<sub>10</sub> due to a size mismatch. The solid solution is illustrated
by density functional theory calculation, X-ray powder diffraction,
and high resolution transmission electron microscopy. The Cr<sup>3+</sup>-doped phosphor shows a red emission band centered at 705 nm, which
is ascribed to the <sup>2</sup>E → <sup>4</sup>A<sub>2</sub> and <sup>4</sup>T<sub>2</sub>(<sup>4</sup>F) → <sup>4</sup>A<sub>2</sub> transitions. When Cr<sup>3+</sup> ions or In<sup>3+</sup> ions are introduced, the full width at half-maximum (fwhm) increased
due to the combination of crystal field splitting, nephelauxetic effect,
and reabsorption
Integration of Transcriptome and Whole Genomic Resequencing Data to Identify Key Genes Affecting Swine Fat Deposition
<div><p>Fat deposition is highly correlated with the growth, meat quality, reproductive performance and immunity of pigs. Fatty acid synthesis takes place mainly in the adipose tissue of pigs; therefore, in this study, a high-throughput massively parallel sequencing approach was used to generate adipose tissue transcriptomes from two groups of Songliao black pigs that had opposite backfat thickness phenotypes. The total number of paired-end reads produced for each sample was in the range of 39.29–49.36 millions. Approximately 188 genes were differentially expressed in adipose tissue and were enriched for metabolic processes, such as fatty acid biosynthesis, lipid synthesis, metabolism of fatty acids, etinol, caffeine and arachidonic acid and immunity. Additionally, many genetic variations were detected between the two groups through pooled whole-genome resequencing. Integration of transcriptome and whole-genome resequencing data revealed important genomic variations among the differentially expressed genes for fat deposition, for example, the lipogenic genes. Further studies are required to investigate the roles of candidate genes in fat deposition to improve pig breeding programs.</p></div
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