Design, Synthesis and Characterization of Palladium-Functionalized Covalent Organic Framework and Its Application as Heterogeneous Catalysis for C-H Arylation of Azoles.

A novel triazine-based covalent organic framework (TFPT-Bz COF) has been constructed by the condensation of 2,4,6-tris(5-formyl-2-pyridinoxy)-1,3,5-triazine (TFPT) and benzidine (BZ) with deep eutectic solvent (DES) as the reaction medium. After the introduction of Pd ions through strong coordination to TFPT-Bz COF matrix, the constructed TFPT-Bz COF/Pd composite exhibited excellent catalytic activity for C-H arylation of azoles with aryl halides in 2-methyltetrahydrofuran. The protocol allows the arylation of a variety of substituted azoles with diverse aryl halides in high to excellent yield. Moreover, the TFPT-Bz COF/Pd catalyst can be recycled several times without significantly reducing its activity.

Conspicuity of breast lesions at different b values on diffusion-weighted imaging.

BACKGROUND: Diffusion-weighted (DW) imaging has shown potential to differentiate between malignant and benign breast lesions. However, different b values have been used with varied sensitivity and specificity. This study aims to prospectively evaluate the influence of b value on the detection and assessment of breast lesions. METHODS: Institutional review board approval and informed patient consent were obtained. Between February 2010 and September 2010, sixty women suspected of having breast cancer by clinical examination and mammography underwent bilateral breast MRI and DW imaging (with maximum b values of 600, 800, and 1000 s/mm(2)). Conspicuity grades of lesions at different b values on DW images were performed. Signal intensity and apparent diffusion coefficient (ADC) values were recorded and compared among different b values by the signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and receiver operating characteristic (ROC) curve. RESULTS: Fifty-seven lesions from 52 recruited patients including 39/57 (68%) malignant and 18/57 (32%) benign were confirmed with pathology. DCE MRI accurately detected 53 lesions with the sensitivity of 93.0% and specificity of 66.7%, and DW imaging accurately detected 51 lesions with the sensitivity of 89.5% and specificity of 100%. There were no significant differences in conspicuity grades compared among the three b values (P = 0.072), although the SNR and CNR of breast lesions decreased significantly with higher b values. Mean ADCs of malignant lesions (b = 600 s/mm(2), 1.07 ± 0.26 × 10-3 mm(2)/s; b = 800 s/mm(2), 0.96 ± 0.22 × 10-3 mm(2)/s; b = 1000 s/mm(2), 0.92 ± 0.26 × 10-3 mm(2)/s) were significantly lower than those of benign lesions (b = 600 s/mm(2), 1.55 ± 0.40 × 10-3 mm(2)/s; b = 800 s/mm(2), 1.43 ± 0.38 × 10-3 mm(2)/s; b = 1000 s/mm(2), 1.49 ± 0.38 × 10-3 mm(2)/s) with all P values <0.001, but there were no significant differences among the three b values (P = 0.303 and 0.840 for malignant and benign lesions, respectively). According to the area under the ROC curves, which were derived from ADC and differentiate malignant from benign lesions, no significant differences were found among the three b values (P = 0.743). CONCLUSIONS: DW imaging is a potential adjunct to conventional MRI in the differentiation between malignant and benign breast lesions. Varying the maximum b value from 600 to 1000 s/mm(2) does not influence the conspicuity of breast lesions on DW imaging at 1.5 T.

Adaptive harmony search algorithm utilizing differential evolution and opposition-based learning.

An adaptive harmony search algorithm utilizing differential evolution and opposition-based learning (AHS-DE-OBL) is proposed to overcome the drawbacks of the harmony search (HS) algorithm, such as its low fine-tuning ability, slow convergence speed, and easily falling into a local optimum. In AHS-DE-OBL, three main innovative strategies are adopted. First, inspired by the differential evolution algorithm, the differential harmonies in the population are used to randomly perturb individuals to improve the fine-tuning ability. Then, the search domain is adaptively adjusted to accelerate the algorithm convergence. Finally, an opposition-based learning strategy is introduced to prevent the algorithm from falling into a local optimum. The experimental results show that the proposed algorithm has a better global search ability and faster convergence speed than other selected improved harmony search algorithms and selected metaheuristic approaches.

[Ultraviolet absorption spectra of iodine, iodide ion and triiodide ion].

Ultraviolet absorption spectra of iodine I2, iodide ion I(-) and triiodide ion I3(-) were studied, and molar absorptivities of these species were determined. Absorption spectrum of I2 aqueous solution appears as an absorption peak at 203 nm with a molar absorptivity of 1.96 x 10(4) L x mol(-1) x cm(-1). Absorption spectrum of I(-) appears as two absorption peaks at 193 and 226 nm with molar absorptivities of 1.42 x 10(4) and 1.34 x 10(4) L x mol(-1) x cm(-1), respectively. When I2 aqueous solution is mixed with KI solution, two absorption peaks appear at 288 and 350 nm, respectively, indicating the formation of I3(-). Using saturation method, molar absorptivities of I3(-) at 288 and 350 nm were determined to be 3.52 x 10(4) and 2.32 x 10(4) L x mol(-1) x cm(-1), respectively.

[Resonance light scattering of aurintricarboxylic acid].

Resonance light scattering (RLS), absorption and fluorescence spectra of aurintricarboxylic acid (ATA) were studied. In solutions with pH 3.7 to pH 11.0, the RLS signal was very weak, but increased sharply with a decrease in pH when pH < 3.7 and reached a maximum at pH 2.7. This enhancement effect of RLS occurred because the negative charged species of ATA were transformed into neutral molecules when pH decreased, and the neutral molecules assembled into supermolecular aggregates. Two peaks at 260 nm and 340 nm, respectively, and a valley at 300 nm, appeared in the RLS spectrum, whereas an absorption peak appeared at 300 nm in the absorption spectrum. This spectral feature reveals that the RLS spectrum was related to the absorption spectrum of ATA. The change in RLS intensity with the wavelength was not accordant with Rayleigh scattering law. The fluorescence excitation and emission spectra of ATA do not overlap, so resonance fluorescence was not involved in the RLS spectrum. Under a given set of experimental conditions, the RLS intensity increased with the increase in ATA concentration, which, however, was not a strictly linear relationship.

Preventive and therapeutic effects of sodium bicarbonate on melamine-induced bladder stones in mice.

The actual preventive and therapeutic effects of alkalinizing urine on melamine-induced bladder stones (cystolith) are not completely known. Using an ideal model, two experiments were conducted in Balb/c mice. The mice were fed a normal diet in controls and a melamine diet in the other groups. The first day was set as experiment-day 1. In "Experiment 1", either low-/mid-/high-dose sodium bicarbonate (SB) or sterile water was administered by intragastric perfusion (once daily) to the mice for 14 days. Relative to the model group, the mean pH of the urine in the SB groups was significantly elevated at 3 h after SB administration, with a significant decrease in cystolith incidence on experiment-day 14. In "Experiment 2", on experiment-day 12, the melamine diet was replaced by a normal diet in 4 groups with melamine withdrawal (MW). Meanwhile, either mid-/high-dose SB or sterile water was administered by intragastric perfusion (once) to the mice in the corresponding groups. On experiment-day 12, after an additional 8 h, the cystolith incidence was significantly reduced in the high-SB, MW + mid-SB and MW + high-SB groups than in the model group. In conclusion, low urinary pH is one of the main determinants of the formation of melamine-associated stones, urinary alkalinization can be achieved by a proper dose of oral SB, and SB acts to prevent and treat melamine-induced cystoliths in mice.

Meglumine: A novel and efficient catalyst for one-pot, three-component combinatorial synthesis of functionalized 2-amino-4H-pyrans.

An efficient one-pot synthesis of functionalized 2-amino-4H-pyrans by a meglumine-catalyzed three-component reaction has been developed. A broad range of substrates including aromatic and heteroaromatic aldehydes, isatin derivatives, and acenaphthenequinone are condensed with enolizable C-H activated compounds and alkylmalonates to give the desired products in high to excellent yields. This methodology provides an alternative approach for rapid access to construct a diversity-oriented library of 4H-pyrans.

One-pot, three-component synthesis of a library of spirooxindole-pyrimidines catalyzed by magnetic nanoparticle supported dodecyl benzenesulfonic acid in aqueous media.

Dodecyl benzenesulfonic acid functionalized silica-coated magnetic nanoparticles (γ-Fe2O3@SiO2-DDBSA) were readily prepared and identified as an efficient catalyst for the synthesis of a library of spirooxindole-pyrimidine derivatives by three-component condensation reaction of barbituric acids, isatins and cyclohexane-1,3-diones. The aqueous reaction medium, easy recovery of the catalyst using an external magnet, and high yields make the protocol sustainable and economic.

Cerium ammonium nitrate-catalyzed multicomponent reaction for efficient synthesis of functionalized tetrahydropyridines.

A highly atom-economic one-pot synthesis of functionalized tetrahydropyridines by a multicomponent condensation reaction of ß-keto ester, two equivalents of aromatic aldehyde, and two equivalents of amine in the presence of a catalytic amount of cerium ammonium nitrate (CAN) is reported. In this way, a series of pharmacologically interesting substituted piperidine derivatives were obtained in moderate to good yields at room temperature.

Health risk evaluation for the inhabitants of a typical mining town in a mountain area, South China.

A previous study investigated metal contamination in farmland and the air in a typical mining town of Guangxi, South China. In this study, the health risks associated with exposure to this contamination that were evaluated for the following routes of exposure are reported: inhalation, dermal contact, ingestion of dust, and ingestion of homegrown vegetables. The findings demonstrated that the inhabitants were at high risk for noncancer effects posed by some of the metals. The total hazard index (THI) of all the pathways was 145 for adults and 560 for children, which were far higher than the normative level 1. The noncancer risk mainly came from air PM(10) pollution through inhalation and ingestion routes of exposure. However, vegetable ingestion also made a noticeable contribution to HI of about 7 for adults and 22 for children. The metals that posed the greatest noncancer risks were Mn for inhalation, and ingestion of dust and vegetables. The total cancer risks of the inhabitants were 1 x 10(-1) (adult) and 3 x 10(-1) (child), which far exceeded the acceptable carcinogen risk of 10(-4) approximately 10(-6) for regulatory purposes. The cancer risk in the village is mainly (97%) associated with As exposure by inhalation and ingestion of dust. However, consumption of vegetables is also associated with a significant cancer risk of up to 2 x 10(-3) for adults and 8 x 10(-3) for children. The cancers associated with this exposure are estimated to be lung cancer and skin cancer. Air particulate-matter pollution was the main source of noncancer risk and cancer risk and originated from vehicular transport of ore through the community. The risk could be tested by a specifically designed epidemiological study.