Density functional theory calculations of copper-doped rutile crystals: Local structural, electronic, optical, and electron paramagnetic resonance properties.

The local structural, electronic, optical, and electron paramagnetic resonance (EPR) properties are uniformly studied for Cu2+ -doped rutile (TiO2 ) crystals by using the density functional theory (DFT) calculations. The local cation-oxygen bond lengths and planar bond angle, band gap, Mulliken charge and overlapping population, density of state (DOS), and UV-Vis absorption spectra are calculated for pure and copper-doped rutile. The smaller overlapping population of Cu-O bonds in the doped system than Ti-O bonds in pure rutile reflects weaker orbital admixtures or covalency of the former. Compared with pure rutile, Cu2+ doping leads to significant redshift of the UV-Vis absorption band and the narrow impurity band in visible and near-infrared regions arising from the Cu2+ d-d transitions and narrowing of the band gap by about 0.636 eV, possibly suggesting enhancement of visible light activity. The Cu dopant induces a spin magnetic moment of 0.74 µB for the doped rutile. The calculated UV-Vis absorption spectra and spin Hamiltonian parameters for copper-doped rutile show reasonable agreement with the experimental data and some improvement related to the previous perturbation formula calculations. Present systematic studies would be helpful to understand the mechanisms of the enhancement in the optical and magnetic properties of this material with transition-metal (especially Cu2+ ) dopants.

Comparative proteomics analysis of differential proteins in respond to doxorubicin resistance in myelogenous leukemia cell lines.

BACKGROUND: Chemoresistance remains a significant challenge in chronic myelogenous leukemia (CML) management, which is one of the most critical prognostic factors. Elucidation the molecular mechanisms underlying the resistance to chemoresistance may lead to better clinical outcomes. RESULTS: In order to identify potential protein targets involved in the drug-resistant phenotype of leukemia, especially the chronic myelogenous leukemia (CML), we used a high-resolution "ultra-zoom" 2DE-based proteomics approach to characterize global protein expression patterns in doxorubicin-resistant myelogenous leukemia cells compared with parental control cells. Ultra-high resolution of 2DE was achieved by using a series of slightly overlapping narrow-range IPG strips during isoelectric focusing (IEF) separation. A total number of 44 proteins with altered abundances were detected and identified by MALDI-TOF or LC-MS/MS. Among these proteins, enolase, aldolase, HSP70 and sorcin were up-regulated in doxorubicin-resistant myelogenous leukemia cell line, whereas HSP27 was down-regulated. Some of the results have been validated by Western blotting. Both enolase and aldolase were first reported to be involved in chemoresistance, suggesting that process of glycolysis in doxorubicin-resistant myelogenous leukemia cells was accelerated to some extent to provide more energy to survive chemical stress. Possible roles of most of the identified proteins in development of chemoresistance in myelogenous leukemia cells were fully discussed. The results presented here could provide clues to further study for elucidating the mechanisms underlying drug resistance in leukemia. CONCLUSIONS: As a whole, under the chemical stress, the doxorubicin-resistant myelogenous leukemia cells may employ various protective strategies to survive. These include: (i) pumping the cytotoxic drug out of the cells by P-glycoprotein, (ii) increased storage of fermentable fuel, (iii) sophisticated cellular protection by molecular chaperones, (iv) improved handling of intracellular calcium, (v) increased glucose utilization via increased rates of glycolysis. In the present study, proteomic analysis of leukemia cells and their drug resistant variants revealed multiple alterations in protein expression. Our results indicate that the development of drug resistance in doxorubicin-resistant myelogenous leukemia cells is a complex phenomenon undergoing several mechanisms.

[Research on wavelength matching of therapeutic laser fiber].

Medical laser adopts optical fibers as spread media, using laser energy for the purpose of diagnostics and therapeutics. The corresponding industry standard is YY/T 0758-2009 General requirements for therapeutic laser fiber, which requires manufacturers to offer applicable wave length (or spectrum range) of the fiber, and the corresponding minimum transmission efficiency of the wave length. This research focuses on the matching of therapeutic laser fiber and laser source, to support and emphasize the importance and reasonability of relative requirements in YY/T 0758-2009.

Effect of microwave pretreatment on pyrolysis of chili straw: thermodynamics, activation energy, and solid reaction mechanism.

In this work, chili straw (CS) was pretreated by microwave at 250 W, 406 W, 567 W, and 700 W. The pyrolysis characteristics, kinetics, thermodynamic parameters, and solid reaction mechanism were investigated. The maximum weight loss rate increases from - 24.72%/°C at P0 to - 28.01%/°C at P700 after microwave pretreatment, and the residual mass decreases from 31.81 at P0 to 26.71% at P700. In addition, microwave pretreatment leads to a decrease in activation energy, ∆H, and ∆G at the end of the pyrolysis (α > 0.7). The solid reaction mechanism of CS pyrolysis is revealed by the Z-master plots method, with un-pretreated CS conforming to P2, D4, F3/2, and F3, respectively. Microwave pretreatment changes the solid reaction mechanism mainly in the third stage, when α = 0.8, the mechanism function changes from f(α) = (1 - α)3 at P0 to f(α) = (1 - α) at P700, and the number of reaction order is reduced, which is profitable for CS pyrolysis.

Antioxidant Properties of Fractions for Unripe Fruits of Capsicum annuum L. var. Conoides.

BACKGROUND: Capsicum plant, especially for C. annuum, is an abundant resource for bioactive antioxidants, but few studies have examined the unripe fruit part of the Capsicum plant. OBJECTIVE: MeOH extract of unripe fruits of C. annuum L. var. conoides (UFCA) was chromatographed over a silica gel column using a gradient of CH2Cl2/MeOH as eluent to produce 9 fractions. Antioxidant activities are evaluated along with cell viabilities of 9 fractions of UFCA. METHOD: The antioxidant properties were analyzed in terms of total phenol content (TPC), total flavonoid content (TFC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, 2,2-azinobis (3-ethyl-benzothiazoline-6- sulfonic acid) (ABTS) radical scavenging, ferric reducing, and ferrous ion-chelating ability. The cell viability of human oral cancer cells (Ca9-22) was measured by 3-(4,5-dimethylthiazol-2-yl)-(3-carboxymethoxyphenyl)-2- (4-sulphophenyl)-2H-tetrazolium (MTS) assay. RESULTS: Except for TFC, fractions (Frs.) 1 and 2 showed the lowest level of these antioxidant properties. Frs. 3 to 9 showed dose-responsive induction for antioxidant effects. Fr. 8 and Fr. 5 respectively showed the highest levels of TPC and TFC for 1162 ± 11 gallic acid equivalents (GAE) (mg)/UFCA (g) and 1295 ± 32 quercetin equivalents (QCE) (mg)/UFCA (g). The cell viability of Fr. 3 was moderately decreased (78.2%) while those of Frs. 4, 5, and 9 were dramatically decreased (55.6, 57.8, and 46.8%, respectively) in oral cancer Ca9-22 cells. UFCA-derived 14 compounds/mixtures derived from Frs. 1, 2, 3, 4, and 8 displayed differential antioxidant performance for these analyses. CONCLUSION: Taken together, fractions of UFCA displayed diverse antioxidant and anticancer effects for oral cancer cells. Some fractions of UFCA may be potent natural antioxidant supplements for antioral cancer cell treatment.

MicroRNA-7/NF-κB signaling regulatory feedback circuit regulates gastric carcinogenesis.

MicroRNAs play essential roles in gene expression regulation during carcinogenesis. Here, we investigated the role of miR-7 and the mechanism by which it is dysregulated in gastric cancer (GC). We used genome-wide screenings and identified RELA and FOS as novel targets of miR-7. Overexpression of miR-7 repressed RELA and FOS expression and prevented GC cell proliferation and tumorigenesis. These effects were clinically relevant, as low miR-7 expression was correlated with high RELA and FOS expression and poor survival in GC patients. Intriguingly, we found that miR-7 indirectly regulated RELA activation by targeting the IκB kinase IKKε. Furthermore, IKKε and RELA can repress miR-7 transcription, which forms a feedback circuit between miR-7 and nuclear factor κB (NF-κB) signaling. Additionally, we demonstrate that down-regulation of miR-7 may occur as a result of the aberrant activation of NF-κB signaling by Helicobacter pylori infection. These findings suggest that miR-7 may serve as an important regulator in GC development and progression.

Reduction of the incidence and mortality of rectal cancer by polypectomy: a prospective cohort study in Haining County.

AIM: To reduce the incidence and mortality of rectal cancer and address the hypothesis that colorectal cancer often arise from precursor lesion(s), either adenomas or non-adenomatous polyps, by conducting a population-based mass screening for colorectal cancer in Haining County, Zhejiang, PRC. METHODS: From 1977 to 1980, physicians screened the population of Haining County using 15 cm rigid endoscopy. Of over 240000 participants, 4076 of them were diagnosed with precursor lesions, either adenomas or non-adenomatous polyps, which were then removed surgically. All individuals with precursor lesions were followed up and reexamined by endoscopy every two to five years up to 1998. RESULTS: After the initial screening, 953 metachronous adenomas and 417 non-adenomatous polyps were detected and removed from the members of this cohort. Further, 27 cases of colorectal cancer were detected and treated. Log-rank tests showed that the survival time among those cancer patients who under went mass screening increased significantly compared to that of other colorectal cancer patients (P<0.0001). According to the population-based cancer registry in Haining County, age-adjusted incidence and mortality of rectal cancer decreased by 41% and 29% from 1977-1981 to 1992-1996, respectively. Observed cumulative 20-year rectal cancer incidence was 31% lower than the expected in the screened group; the mortality due to rectal cancer was 18% lower than the expected in the screened group. CONCLUSION: Mass screening for rectal cancer and precursor lesions with protocoscopy in the general population and periodical following-up with routine endoscopy for high-risk patients may decrease both the incidence and mortality of rectal cancer.