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The first total synthesis of wikstrol A and wikstrol B was achieved via Sharpless asymmetric dihydroxylation, Sonogashira and rhodium-catalyzed oxidative coupling as key steps. , The first total synthesis of wikstrol A and wikstrol B was achieved by employing aldol reaction, Sharpless asymmetric dihydroxylation, regioselective iodination, Sonogashira coupling, and rhodium-catalyzed oxidative coupling as key steps. The structure of the key intermediate for wikstrol A was confirmed via its derivative by single-crystal X-ray analysis.

Background: The symptoms of patients with malignant biliary obstruction (MBO) could be effectively alleviated with percutaneous transhepatic biliary drainage (PTBD). Postoperative infections were considered as challenging issues for clinicians. In this study, the risk factors of biliary infection in patients after PTBD were analyzed. Methods: From July 2003 to September 2010, 694 patients with MBO received PTBD treatment. Bile specimens were also collected during PTBD. All relevant information and results were collected, including gender, age, obstruction time, types of primary tumor, sites of obstruction, drainage style, tumor stage, hemoglobin, phenotype of peripheral blood monocyte (Treg), total bilirubin, direct bilirubin, albumin, Child–Pugh score, and results of bile bacterial culture. Results: For the 694 patients involved in this study, 485 were male and 209 were female, with a mean age of 62 years (ranged 38–78 years). For the bile culture, 57.1% patients (396/649) were negative and 42.9% patients showed positive (298/694), and then 342 strains of microorganism were identified. The risk factors of biliary system infection after PTBD included: age (χ2 = 4.621, P = 0.032), site of obstruction (χ2 = 17.450, P < 0.001), drainage style (χ2 = 14.452, P < 0.001), tumor stage (χ2 = 4.741, P = 0.029), hemoglobin (χ2 = 3.914, P = 0.048), Child–Pugh score (χ2 = 5.491, P = 0.019), phenotype of peripheral blood monocyte (Treg) (χ2 = 5.015, P = 0.025), and results of bile bacterial culture (χ2 = 65.381, P < 0.001). Multivariate analysis suggested that high-risk factors were drainage style, Child–Pugh score, and results of bile culture. Conclusions: The risk factors of biliary infection after PTBD included: age, site of obstruction, drainage style, tumor stage, hemoglobin, Child–Pugh score, phenotype of peripheral blood monocyte (Treg), and results of bile culture. It was further concluded that drainage style, Child–Pugh score, and results of bile culture were independent risk factors.

A highly sensitive and specific assay for detecting mRNA splice variants is developed based on ligation-dependent PCR., Alternative messenger RNA (mRNA) splicing is a basic mechanism of gene regulation. In general, reverse transcription and polymerase based primer extension limit the sensitivity and selectivity of the current detection of mRNA splice variants, respectively. Here, we show that, using the ligation of two properly designed probes at the exon junction combined with universal PCR amplification, as little as a single copy of a mRNA splice variant per cell can be accurately determined, and the dynamic range covers six orders of magnitude. Three mRNA splice variants were measured from total RNA samples derived from different cell lines. Moreover, by encoding the ligation probes with different lengths, multiplexed mRNA splice variants can be simultaneously detected in one-tube PCR amplification using electrophoretic separation.

A novel class of pH-responsive hollow poly(L-glutamic acid)/chitosan (PLGA/CS) nanogels was fabricated by a templating approach, which was mild and surfactant free, and combined with a “grafting from” method and intermacromolecular crosslinking technique. The surface grafting, crosslinking reaction, nanogel fabrication and microstructure were investigated by FTIR, 1H NMR, XRD, TGA, light scattering, and electron microscopy. The size of the resultant PLGA/CS nanogels could be accurately controlled by simply changing the size of the silica template. The nanogels responded to changes in environmental pH, elucidated according to the variation of the size of the nanogels and zeta potential at different pH values. Taking water-soluble antineoplastic agent mitoxantrone (MTX) as a model drug, the nanogels presented high loading ability at high-pH environment and rapid MTX release behavior under acidic conditions. MTT assays used to study the in vitro cytotoxicity of PLGA/CS nanogels showed a negligible cytotoxicity in mouse fibroblast L929 cells. Compared with bare MTX, MTX loaded PLGA/CS nanogels exhibited an enhanced inhibition effect to human gastric carcinoma SGC7901 cells. Fluorescence microscopy and flow cytometry analysis results demonstrated efficient cellular uptake of the PLGA/CS nanogels into the cells. These studies suggest that such pH-responsive PLGA/CS hollow nanogels might have great potential in controlled drug delivery systems.

In situ generated iron‐based Knölker complexes were found to be efficient catalysts in a fully non‐noble metal Cu–Fe photocatalytic water reduction system. These mononuclear iron catalysts were able to generate hydrogen up to 15 times faster than previously reported [Fe3(CO)12]. A reductive quenching mechanism was shown to operate by fluorescence experiments.

Sediments play an important role in carbon cycle as the important sources and sinks of carbon.The role of sediments in the carbon cycle is closely related to the forms and distribution of inorganic carbon in the sediments.The forms of inorganic carbon have different capacity in the carbon cycle and recycle.Forms and changes of inorganic carbon in the sediments were essential for the fluxes and processes of carbon across the water-sediment interface.The study of inorganic carbon forms is the basis and premise for discussing their contribution to carbon cycling.In this wok,the sequential extraction method was employed to extract inorganic carbon forms in sediments from Dali Lake.The form distribution characters of inorganic carbon in surface sediments and sediment cores were studied.The correlations between inorganic carbon and physical-chemistry characteristics such as total organic carbon(TOC),total nitrogen(TN),total phosphorus(TP) and biogenic silicate(BSi) were discussed in sediment cores.The results showed that the dominant form of inorganic carbon was NH2OH·HCl form both in surface sediment and sediment cores;The content of NH2OH·HCl form in sediments ranges from 6.26 to 17.51 mg/g,with mean content of 14.02 mg/g,accounted for 82.77% of the total inorganic carbon in the sediments.The contents of inorganic carbon forms in surface sediment are rank as: NH2OH·HCl form HCl form NaCl form NH3·H2O form NaOH form.In terms of the horizontal characteristics,the central area was the high value area of inorganic carbon form,the east and north area were the low value area in the lake.Water depth and inorganic carbon present a good positive correlation(R2=0.86,P0.01).The correlationship and the horizontal characteristics of inorganic carbon implied that the terrigenous material which were carried by inflowing rivers have dilute effect on sediments.The supersaturation coefficients of Calcium carbonate in different year in Dali Lake are far greater than 1(31.59IAP/Ksp166.92).The calculation results showed that calcium carbonate was supersaturation in the lake and implied that the aquatic environmental conditions were beneficial to authigenic carbonate precipitation in Dali Lake.In sediment cores,the content of NH2OH·HCl form ranges from 5.29 to 21.72 mg/g,with mean content of 12.90 mg/g,accounted for 82.21% of the total inorganic carbon in the sediments.The contents of NH2OH·HCl form in sediment cores of DLNE-3 and DLNE-5 are obviously higher than DLNE-8 and DLNE-10.The former lied in deep water area are weakly affected by the dilution effect of terrigenous input,which is beneficial to authigenic carbonate precipitation.The latter lied in shallow water area are strongly affected by the dilution effect of terrigenous input,which is not helpful for authigenic carbonate precipitation.The correlations between inorganic carbon and nitrogen,phosphorus,biogenic silicate in the sediments implied that nutrients rising can promote the formation of calcium carbonate supersaturation.In addition,the physical and chemical properties changes in aquatic environment caused by photosynthesis was one of the important factors leading to precipitation of carbonate.

SWAT model and measured data were used to simulate the Non-Point Source(NPS) N and P pollution from 2001to 2010 in Lake Nansi watershed.The spatial distribution of the pollution was analyzed,and the contribution of all the rivers in watersheds to the pollution of Lake Nansi were calculated.The key areas with serious pollution were distinguished.The results indicated that:(1) typical watersheds were simulated with SWAT model,and then the derived models were used to simulate the Lake Nansi watershed.This method can not only improve efficiency,but also with higher simulation accuracy.The simulation results in the east of the lake were better than those in the west part of the lake,which indicated that SWAT model was suitable for the hilly areas.(2) The NPS pollution was serious in Lake Nansi watershed.The nitrogen loading exceeded the criteria in almost all regions,and the phosphorus loading exceeded the criteria in more than 40% of the region.The NPS pollution was more serious in east than that in west of the lake.The Guangfu River watershed was the major contributor to the NPS pollution in Lake Nansi watershed.(3) The soluble nitrogen,flowed into the lake through streams,is the main form of loading in Lake Nansi watershed.While,the P loading in Lake Nansi watershed was mainly in the form of adsorption,which ran into river with sediment.

The fertilizer management and the selection of rice cultivars play a vital role in rice production to maximize yield and minimize fertilizer cost. Many researches have elucidated the combined increase of nitrogen (N) accumulation and N use efficiency (NUE) in different rice genotypes, however, the accumulation, translocation, distribution of phosphorus (P) and potassium (K), and the correlation of N, P and K absorption characteristics and their relationships with grain yield in rice cultivars with different NUE is still obscure. For this purpose, two rice cultivars differing in NUE were chosen for this study, one with high-NUE (Dexiang 4103) and the other with low-NUE (Yixiang 3724). Fertilizers were applied at three levels, including low (75 kg N·hm-2, 37.5 kg P2O5·hm-2, 75 kg K2O·hm-2), medium (150 kg N·hm-2, 75 kg P2O5·hm-2, 150 kg K2O·hm-2), high rate (225 kg N·hm-2, 112.5 kg P2O5·hm-2, 225 kg K2O·hm-2). A no-N treatment was included for each level as the control. The results showed that there were obvious interacting effects of cultivars and fertilizer levels on grain yield, as well as the absorption and translocation of P and K. Rice cultivars exhibited markedly stronger effects on total spikelets and the translocation of P and K in leaves, compared to fertilizer levels. The opposite trend was observed for grain yield, P and K accumulation at the main growth stages, and P and K translocation in stem and leaf sheaths. Compared with other treatments, the combined application of NPK fertilizers at medium level promoted nutrient accumulation, increased the nutrient harvest index, facilitated nutrient translocation in vegetative organs, and ultimately improved grain yield in both cultivars. The equilibrium relationship between N, P and K accumulation and grain yield indicated that the grain yield associated with high-NUE cultivar could reach more than 10,000 kg hm-2, with N, P, and K requirements of 180.8-213.3, 47.3-54.7, and 223.5-259.1 kg hm-2, respectively. Additionally, the correlation analysis revealed that accumulation and translocation of P, K during different growth stages was significantly (P < 0.05) related to grain yield and nutrient accumulation in different NUE cultivars. This study suggested that varieties with high-NUE also has high P and K use efficiencies, indicating that the conventional screening of varieties with high P or K use efficiencies can be included in the selection of high-NUE varieties. The increase of P and K accumulation and translocation during the period from heading to maturity was helpful to maintain a high-yield and NUE in rice production.

The magnetic polymer microcapsules, as a promising environmental stimuli-responsive delivery vehicle, have been increasingly exploited to tackle the problem of remotely navigated delivery. This study presented a novel design and fabrication of magnetic poly(L-glutamic acid)/chitosan (PGA/CS) microcapsules. Magnetic Fe3O4 nanoparticles were in situ synthesized inside nanoporous PGA/CS microcapsules and resultant magnetic PGA/CS microcapsules were characterized. Mitoxantrone (MTX), an antineoplastic drug, was chosen as a water-soluble model drug to research the loading and release properties of the microcapsules. The results showed the carboxylate groups of PGA within polyelectrolyte walls could be used as binding sites for the absorption of iron ions and reaction sites for the synthesis of magnetic nanoparticles. Magnetic PGA/CS microcapsules were dissected using a dual-beam scanning electron microscope/focused ion beam (SEM/FIB) for morphological and microstructural examination. It was found that Fe3O4 nanoparticles with size of about 10nm were homogeneously dispersed in the polymer matrix and adhered to the pore walls of the microcapsules. Increasing the concentration of iron ions led to an increasing loading content of Fe3O4 nanoparticles and an increase in the resultant magnetization. The magnetic PGA/CS microcapsules could be easily manipulated by an external magnetic field. The MTX loading capacity depended on loading time and MTX concentration. The high loading could be ascribed to spontaneous deposition of MTX induced by electrostatic interaction. The microcapsules exhibited sustained release behavior. The MTX release from microcapsules could be best described using Korsmeyer-Peppas and Baker-Lonsdale models, indicating the diffusion mechanism of drug release from both PGA/CS microcapsules and magnetic PGA/CS microcapsules. Therefore, the novel magnetic PGA/CS microcapsules are expected to find application in drug delivery systems because of the properties of magnetic sensitivity, high drug loading and sustained release.

The reduction of CO 2 to CO over SnS 2 was firstly reported. In this paper, the SnS 2 was synthesized successfully via a hydrothermal method and characterized by XRD, DRS and electrochemical equipment. The results indicate that it can respond to visible light and be probably capable of reducing CO 2 to CO without external bias. The property of reducing CO 2 was further checked out on GS analysis. The CO output reached 80 ppm at the temperature of 25 °C, but without temperature control, the yield came to 200 ppm, revealing the temperature plays a very important role in reducing CO 2 to CO. Except trace amount of CH 4 , the CO was the main product with nearly 100% selectivity. These attractive results make us believe that SnS 2 is promising candidate for the reduction of CO 2 .