Leveraging Electron Push-Pull Effect for Catalytic Polymerization and Degradation of a Cyclobutane Monomer System.

Ring-opening polymerization (ROP) offers a striking solution to solve problems encountered in step-growth condensation polymerization, including precise control over molecular weight, molecular weight distribution, and topology. This has inspired our interest in ROP of cycloalkanes with an ultimate goal to rethink polyolefins, which clearly poses a number of challenges. Practicality of ROP of cycloalkanes is actually limited by their low polymerizability and elusive mechanisms which arise from significantly varied ring size and non-polar C-C bonds in monomers. In this work, by using Lewis acid/Brønsted base/C(sp3)-H initiator system previously developed in our laboratory, we focus on cyclobutanes and explore the positional and electronic effects of substituents on the ring, namely electron push-pull effect, in promoting controlled polymerization to afford densely functionalized poly(cyclobutanes), as well as catalytic degradation of obtained polymers for upcycling. More importantly, experiments and DFT calculations unveil considerable population of Lewis-acid-induced thermostabilized 1,4-zwitterions, which distinguish cyclobutanes from cyclopropanes and others. All these findings would shed light on catalytic synthesis and degradation of saturated all-carbon main-chain polymers, as well as small molecule transformations of cyclobutanes.

Regulatory effects of Hemin on prevention and rescue of salt stress in rapeseed (Brassica napus L.) seedlings.

BACKGROUND: Salt stress severely restricts rapeseed growth and productivity. Hemin can effectively alleviate salt stress in plants. However, the regulatory effect of Hemin on rapeseed in salt stress is unclear. Here, we analyzed the response and remediation mechanism of Hemin application to rapeseed before and after 0.6% (m salt: m soil) NaCl stress. Experiment using two Brassica napus (AACC, 2n = 38) rapeseed varieties Huayouza 158R (moderately salt-tolerant) and Huayouza 62 (strongly salt-tolerant). To explore the best optional ways to improve salt stress resistance in rapeseed. RESULTS: Our findings revealed that exogenous application of Hemin enhanced morph-physiological traits of rapeseed and significantly attenuate the inhibition of NaCl stress. Compared to Hemin (SH) treatment, Hemin (HS) significantly improved seedlings root length, seedlings height, stem diameter and accumulated more dry matter biomass under NaCl stress. Moreover, Hemin (HS) significantly improved photosynthetic efficiency, activities of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), and decreased electrolyte leakage (EL) and malondialdehyde (MDA) content, thus resulting in the alleviation of oxidative membrane damage. Hemin (HS) showed better performance than Hemin (SH) under NaCl stress. CONCLUSION: Hemin could effectively mitigate the adverse impacts of salt stress by regulating the morph-physiological, photosynthetic and antioxidants traits of rapeseed. This study may provide a basis for Hemin to regulate cultivated rapeseed salt tolerance and explore a better way to alleviate salt stress.

Construction of ecological network based on habitat risks identifying by points of interest: A case study of Wuhan Metropolitan Area.

Ecological network construction plays a key role in ecological restoration, which can effectively mitigate negative effects of habitat fragmentation on biodiversity. Here, we proposed an improved analytical framework for ecological network identification. Specifically, ecological sources were identified using a three-dimension indicator system in terms of form, quality and functions of habitats. Ecological resistance surfaces were determined based on the incorporation of points of interest data that could characterize human activities into habitat risk assessment (HRA) model, while ecological corridors were extracted using circuit theory approach. With Wuhan Metropolitan Area as a case, we explored the key points and structures of ecological network. Moreover, we compared the construction method of ecological resistance surface based on points of interest and HRA model with traditional methods that determined by land use types and by traditional HRA model, to validate the proposed framework. The results showed that the ecological source area of Wuhan Metropolitan Area was 15200 km2, the length of ecological corridor was 1956.68 km, and that there were 87 ecological "pinch points" and 67 ecological barrier points. Compared with traditional methods, the material circulation, network complexity, and ecological connectivity of the ecological network identified by the improved framework were significantly improved, with network closure, dot-line ratio, and network connectivity being increased by 61.5%, 28.1% and 28.7% on average. The identified ecological "pinch points" and barrier points could provide precise decision-making support for ecological restoration and conservation.

Combined transcriptomic and metabolomic analysis of alginate oligosaccharides alleviating salt stress in rice seedlings.

BACKGROUND: Salt stress is one of the key factors limiting rice production. Alginate oligosaccharides (AOS) enhance plant stress resistance. However, the molecular mechanism underlying salt tolerance in rice induced by AOS remains unclear. FL478, which is a salt-tolerant indica recombinant inbred line and IR29, a salt-sensitive rice cultivar, were used to comprehensively analyze the effects of AOS sprayed on leaves in terms of transcriptomic and metabolite profiles of rice seedlings under salt stress. RESULTS: In this experiment, exogenous application of AOS increased SOD, CAT and APX activities, as well as GSH and ASA levels to reduce the damage to leaf membrane, increased rice stem diameter, the number of root tips, aboveground and subterranean biomass, and improved rice salt tolerance. Comparative transcriptomic analyses showed that the regulation of AOS combined with salt treatment induced the differential expression of 305 and 1030 genes in FL478 and IR29. The expressed genes enriched in KEGG pathway analysis were associated with antioxidant levels, photosynthesis, cell wall synthesis, and signal transduction. The genes associated with light-trapping proteins and RLCK receptor cytoplasmic kinases, including CBA, LHCB, and Lhcp genes, were fregulated in response to salt stress. Treatment with AOS combined with salt induced the differential expression of 22 and 50 metabolites in FL478 and IR29. These metabolites were mainly related to the metabolism of amino and nucleotide sugars, tryptophan, histidine, and ß -alanine. The abundance of metabolites associated with antioxidant activity, such as 6-hydroxymelatonin, wedelolactone and L-histidine increased significantly. Combined transcriptomic and metabolomic analyses revealed that dehydroascorbic acid in the glutathione and ascorbic acid cycles plays a vital role in salt tolerance mediated by AOS. CONCLUSION: AOS activate signal transduction, regulate photosynthesis, cell wall formation, and multiple antioxidant pathways in response to salt stress. This study provides a molecular basis for the alleviation of salt stress-induced damage by AOS in rice.

Physiological mechanism of exogenous brassinolide alleviating salt stress injury in rice seedlings.

Brassinolide (BR) is a sterol compound, which can regulate plant seed germination, flowering, senescence, tropism, photosynthesis, stress resistance, and is closely related to other signaling molecules. This study aimed to evaluate the ability of soaking with BR to regulate growth quality at rice seedling stage under salt stress. Results demonstrated that salt stress increases the contents of ROS, MDA, Na+ and ABA, reduces the the SPAD value, net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), maximum fluorescence (Fm), variable fluorescence (Fv), the effective photochemical efficiency of PSII (Fv/Fo) and the maximum photochemical efficiency of PSII (Fv/Fm), reduces the biomass production and inhabits plant growth. All of these responses were effectively alleviated by BR soaking treatment. Soaking with BR could increase the activities of superoxide dismutase, peroxidase, catalase, ascorbate peroxidase, and the contents of ascorbic acid, glutathione as well as soluble protein and proline, while BR soaking treatment inhibited the accumulation of ROS and reduced the content of MDA. BR soaking significantly reduced the contents of Na+ and increased the contents of K+ and Ca2+, indicating that soaking with BR is beneficial to the excretion of Na+, the absorption of K+ and Ca2+ and the maintenance of ion balance in rice seedlings under salt stress. BR also maintained endogenous hormone balance by increasing the contents of indoleacetic acid (IAA), zeatin (ZT), salicylic acid (SA), and decreasing the ABA content. Soaking with BR significantly increased the SPAD value, Pn and Tr and enhanced the Fm, Fv/Fm and Fv/Fo of rice seedlings under NaCl stress, protected the photosythetic system of plants, and improved their biomass. It is suggested that BR was beneficial to protect membrane lipid peroxidation, the modulation of antioxidant defense systems, ion balance and endogenous hormonal balance with imposition to salt stress.

Organo/Transition-Metal Combined Catalysis Rejuvenates Both in Asymmetric Synthesis.

Since its advent two decades ago, asymmetric organo/transition-metal combined catalysis (AOMC), including cooperative catalysis and relay catalysis, has leveraged redistribution of chemical bonds to build up molecular complexity and enantio-differentiation to form individual enantiomers with activations from versatile organocatalysts and transition-metal complexes. The goal of this perspective is to provide readers with the fundamental attributes of AOMC─orthogonality, kinetics, mechanism, and selectivity─to understand how an organocatalyst and a transition-metal complex would collaborate to enable fruitful new reaction development and what are the intrinsic pathways of unproductive events, such as catalyst self-quenching. In closing, future opportunities of AOMC have been directed toward the prediction of effective catalyst combination, introducing enzyme catalysis, and a focus on transient radical intermediate, to animate this area in the years to come.

Chiral Indoline-2-carboxylic Acid Enables Highly Enantioselective Catellani-type Annulation with 4-(Bromomethyl)cyclohexanone.

Chiral indoline-2-carboxylic acid has been identified to enable a highly enantioselective Catellani-type annulation of (hetero)aryl, alkenyl triflate and conjugated vinyl iodides with 4-(bromomethyl)cyclohexanone, directly assembling a diverse range of chiral all-carbon bridged ring systems. Control experiments and DFT calculations suggest that the coordinating orientation of the chiral amino acid to the arylpalladium(II) center allows for high levels of stereochemical control.

Effects of polygonatum polysaccharide on p38 MAPK/N-cadherin in zebrafish with Alzheimer disease / 中国药理学与毒理学杂志

OBJECTIVE To study the effect of polygonatum polysaccharide on zebrafish with Alzheimer disease. METHODS Zebrafish were trained in T maze for 7 d. The 40 zebrafish successfully trained were divided into 4 groups:blank group, model group, positive group and polygonatum polysaccharide group. Model group, positive group and polygonatum polysaccharide group were put in AlCl3100μg·L-1 for 6 d. The positive group was exposed to Huperzine A solution 4μg·L-1, and the polygonatum polysaccharide group was exposed to polygonatum polysaccharide solution 6 g·L-1 for 6 d. The model group was not treated, and the blank group was not treated. Each stage of zebrafish was recorded by video, and the time of each group in the EC region was analyzed. After administration, the brain tissue was taken out and the expression of N-cadherin, P38 and p-P38 protein factors was determined by Western blotting. RESULTS In behavior, the analysis of the time spent in the EC area, the blank group, the positive group and the polygonatum polysac?charide group were compared with the model group, respectively, there were statistically significant differences (P<0.05). At the protein level, compared with the model group, the P38 and p-P38 proteins in the positive group and the polygonatum polysaccharide group were down-regulated, while the N-cadherin protein was up-regulated, with statistical difference (P<0.05). CONCLUSION Polygonatum polysaccharide can improve the learning and memory ability of zebrafish with Alzheimer disease by up regulating the protein level of N-cadherin and hindering P38 phosphorylation.

Genotoxic properties of materials used for endoprostheses: Experimental and human data.

Approximately 2 million endoprostheses are implanted annually and metal ions as well as particles are released into the body from the materials which are used. This review describes the results of studies concerning genotoxic damage caused by artificial joints. DNA damage leads to various adverse long-term health effects in humans including cancer. Experiments with mammalian cells showed that metal ions and particles from orthopedic materials cause DNA damage. Induction of chromosomal aberrations (CA) was found in several in vitro experiments and in studies with rodents with metals from orthopedic materials. Human studies focused mainly on induction of CA (7 studies). Only few investigations (4) concerned sister chromatid exchanges, oxidative DNA damage (2) and micronucleus formation (1). CA are a reliable biomarker for increased cancer risks in humans) and were increased in all studies in patients with artificial joints. No firm conclusion can be drawn at present if the effects in humans are due to oxidative stress and if dissolved metal ions or release particles play a role. Our findings indicate that patients with artificial joints may have increased cancer risks due to damage of the genetic material. Future studies should be performed to identify safe materials and to study the molecular mechanisms in detail.

Organocatalyzed Birch Reduction Driven by Visible Light.

The Birch reduction is a powerful synthetic methodology that uses solvated electrons to convert inert arenes to 1,4-cyclohexadienes-valuable intermediates for building molecular complexity. Birch reductions traditionally employ alkali metals dissolved in ammonia to produce a solvated electron for the reduction of unactivated arenes such as benzene (Ered < -3.42 V vs SCE). Photoredox catalysts have been gaining popularity in highly reducing applications, but none have been reported to demonstrate reduction potentials powerful enough to reduce benzene. Here, we introduce benzo[ghi]perylene imides as new organic photoredox catalysts for Birch reductions performed at ambient temperature and driven by visible light from commercially available LEDs. Using low catalyst loadings (<1 mol percent), benzene and other functionalized arenes were selectively transformed to 1,4-cyclohexadienes in moderate to good yields in a completely metal-free reaction. Mechanistic studies support that this unprecedented visible-light-induced reactivity is enabled by the ability of the organic photoredox catalyst to harness the energy from two visible-light photons to affect a single, high-energy chemical transformation.

Bromine Radical Catalysis by Energy Transfer Photosensitization.

We report here a mild, safe, and user-friendly bromine radical catalysis system that enables efficient [3 + 2] cycloaddition of diversely substituted vinyl- and ethynylcyclopropanes with a broad range of alkenes, including drug-like molecules and pharmaceuticals. Key to the success is the use of photosensitizing triplet-state ß-fragmentation of a judiciously selected precatalyst, cinnamyl bromide, to generate bromine radicals in a controlled manner using parts per million-level photocatalyst (i.e., 4CzIPN) loading.

Organocatalyzed Photoredox Radical Ring-Opening Polymerization of Functionalized Vinylcyclopropanes.

Organocatalyzed photoredox radical ring-opening polymerization (rROP) of vinylcyclopropanes (VCPs) is employed for the synthesis of polymers with controlled molecular weight (MW), dispersity, and composition. Herein, we report the study on the rROP of a variety of VCP monomers bearing diverse functional groups (such as amide, alkene, ketal, urea, hemiaminal ether, and so on) under organocatalyzed conditions with varying light sources and temperature. Notably, VCP monomers bearing natural product functionality or their derivatives can be polymerized in a controlled manner to produce poly(VCPs) with predictable MW, low dispersity, tunable composition, high thermal stability, and tailored glass transition temperature (T g), ranging 39 to 107 °C. Lastly, successful "grafting through" synthesis of molecular brush copolymers containing 1.0 or 5.0 kDa polydimethylsiloxane (PDMS) side chains from readily accessible EtVCP-PDMS macromonomers further demonstrates the robustness of this organocatalyzed photoredox rROP.

Effect of nicorandil on cardiac function in patients undergoing cardiac valve replacement under cardiopulmonary bypass: detection of amino-terminal pro-brain natriuretic peptide concentrations in serum / 中华麻醉学杂志

Objective:To evaluate the effect of nicorandil on cardiac function in the patients undergoing cardiac valve replacement under cardiopulmonary bypass (CPB).Methods:Forty patients of both sexes, aged 18-64 yr, of American Society of Anesthesiologists physical status Ⅱ-Ⅳ, with New York Heart Association class Ⅱ or Ⅲ, with body mass index of 18-25 kg/m 2, scheduled for elective cardiac valve replacement under general anesthesia and CPB, were divided into conventional group( n=20) and nicorandil group( n=20) according to a randomized number table method.In nicorandil group, nicorandil 10-60 μg·kg -1·h -1 was intravenously infused starting from the end of anesthesia induction until the the end of operation.Mean arterial pressure was maintained at 60-80 mmHg in two groups.Venous blood samples were collected before induction of anesthesia (T 0) and at 6, 12, 24, 48 and 72 h after operation (T 1-5) and at the time of discharge (T 6) to determine the serum amino-terminal pro-brain natriuretic peptide (NT-proBNP) concentrations.The occurrence of myocardial ischemic events or arrhythmia before and after operation was recorded.The defibrillation during intraoperative restoration of spontaneous heart beat, restoration of spontaneous heart beat, medication during restoration of spontaneous heart beat, and cardiac rhythm after restoration of spontaneous heart beat were recorded.The intra- and post-operative requirements for cardiovascular drugs were recorded.The mechanical ventilation time and intensive care unit stay time were also recorded. Results:Compared with conventional group, the serum NT-proBNP concentration was significantly decreased at T 5 and T 6, the mechanical ventilation time and intensive care unit stay time were shortened, the consumption of intraoperative norepinephrine and postoperative dobutamine was decreased ( P<0.05), and no significant change was found in the incidence of postoperative myocardial ischemic events or arrhythmias, defibrillation rate during restoration of spontaneous heart beat, rate of spontaneous recovery of heart beat, cardiac rhythm after restoration of spontaneous heart beat or medication during restoration of spontaneous heart beat in nicorandil group ( P>0.05). Conclusion:Intravenous infusion of nicorandil can improve the cardiac function and is helpful in improving short-term prognosis in the patients undergoing cardiac valve replacement under CPB.

Recent Progress in Asymmetric Relay Catalysis of Metal Complex with Chiral Phosphoric Acid.

Asymmetric metal/organo relay catalysis, utilizing a metal complex and a chiral organocatalyst in a one-pot cascade reaction, is aimed to sequentially impart activation on multiple steps by distinct catalysts. Such a catalysis merges the advantages of both metal catalysis and organocatalysis, providing step-economy, and, more importantly, the potential to achieve inaccessible reactivity by a single catalyst. Chiral phosphoric acids are among the most robust organocatalysts, rendering a broad range of enantioselective bond-forming reactions. The combination of metal complexes and chiral phosphoric acids in a single vessel has been well documented. In particular, the asymmetric relay catalysis of metal complex with chiral phosphoric acid has grown rapidly since 2008. Several excellent reviews have been published to cover almost all examples in this area from 2008 to early 2014; therefore, in this chapter, we will mainly highlight progress from 2014 to mid-2019.

Deoxynivalenol Induces Intestinal Damage and Inflammatory Response through the Nuclear Factor-κB Signaling Pathway in Piglets.

Deoxynivalenol (DON) is highly toxic to animals and humans, but pigs are most sensitive to it. The porcine mucosal injury related mechanism of DON is not yet fully clarified. Here, we investigated DON-induced injury in the intestinal tissues of piglet. Thirty weanling piglets [(Duroc × Landrace) × Yorkshire] were randomly divided into three groups according to single factor experimental design (10 piglets each group). Piglets were fed a basal diet in the control group, while low and high dose groups were fed a DON diet (1300 and 2200 µg/kg, respectively) for 60 days. Scanning electron microscopy results indicated that the ultrastructure of intestinal epithelial cells in the DON-treated group was damaged. The distribution and optical density (OD) values of zonula occludens 1 (ZO-1) protein in the intestinal tissues of DON-treated groups were decreased. At higher DON dosage, interleukin (IL)-1ß, IL-6, and tumor necrosis factor-α mRNA levels were elevated in the intestinal tissues. The mRNA and protein levels of NF-κB p65, IκB-α, IKKα/ß, iNOS, and COX-2 in the small intestinal mucosa were abnormally altered with an increase in DON concentration. These results indicate that DON can persuade intestinal damage and inflammatory responses in piglets via the nuclear factor-κB signaling pathway.

Upregulation of microRNA-133a and downregulation of connective tissue growth factor suppress cell proliferation, migration, and invasion in human glioma through the JAK/STAT signaling pathway.

Recently, microRNA-133a (miR-133a) has been found to function in many diseases in previous studies, yet few studies have been focused on its role in glioma. This study aims to investigate the mechanism of miR-133a/CTGF on regulating the malignant phenotypes of glioma cells via the JAK/STAT signaling pathway. Sixty-five human glioma specimens were collected and 30 normal brain tissues were selected as controls. The expression of connective tissue growth factor (CTGF) and miR-133a in tissues was detected, and the relationship between their expression and the clinicopathological features as well as prognosis of glioma was analyzed. MiR-133a and CTGF expression in U87, A172, and HEB cell lines was determined. The expression of CTGF, signaling pathway-, proliferation-, migration-, invasion-, apoptosis- and epithelial-mesenchymal transition (EMT)-related factors was detected. A number of assays were used to detect cell proliferation, migration, invasion, cell cycle, apoptosis, glioma growth, and the targeting site between CTGF and miR-133a. MiR-133a was downregulated and CTGF was upregulated in human glioma tissues and cells. MiR-133a and CTGF expression was related to glioma's WHO staging and size. Downregulated miR-133a and upregulated CTGF caused unfavorable prognosis in glioma. Upregulated miR-133a suppressed CTGF expression and the activation of JAK/STAT signaling pathway, thereby constraining cell colony formation, proliferation, migration and invasion, and promoting apoptosis in glioma. Our study reveals that upregulated miR-133a and downregulated CTGF suppress cell proliferation, migration, and invasion in human glioma through the inhibition of the JAK/STAT signaling pathway.

Controlling Polymer Composition in Organocatalyzed Photoredox Radical Ring-Opening Polymerization of Vinylcyclopropanes.

Although radical polymerizations are among the most prevalent methodologies for the synthesis of polymers with diverse compositions and properties, the intrinsic reactivity and selectivity of radical addition challenge the ability to impart control over the polymerization propagation and produce polymers with defined microstructure. Vinylcyclopropanes (VCPs) can be polymerized through radical ring-opening polymerization to produce polymers possessing linear (l) or cyclic (c) repeat units, providing the opportunity to control polymer structure and modify the polymer properties. Herein, we report the first organocatalyzed photoredox radical ring-opening polymerization of a variety of functionalized VCP monomers, where high monomer conversions and spatial and temporal control were achieved to produce poly(VCPs) with predictable molecular weight and low dispersity. Through manipulating polymerization concentration and temperature, tunable l or c content was realized, allowing further investigation of thermal and viscoelastic materials properties associated with these two distinct compositions. Unexpectedly, the photoredox catalysis enables a postpolymerization modification that converts l content into the c content. Combined experimental and computational studies suggested an intramolecular radical cyclization pathway, where cyclopentane and cyclohexane repeat units are likely formed.

[Differences in light and heat utilization efficiency and yield of soybean in two ecological zones and their response to chemical control regulators]. / ä¸¤ä¸ªç”Ÿæ€åŒºå¤§è±†å ‰çƒ­èµ„æºåˆ©ç”¨çŽ‡å’Œäº§é‡çš„å·®å¼‚åŠå¯¹åŒ–æŽ§å‰‚çš„å“åº”.

The field experiment was conducted at two farms at Jiusan in Heihe (the fourth accumulated temperature zone) and at Lindian County of Daqing (the second accumulated temperature zone), both sites located in Heilongjiang Province, China. With soybean Kenfeng 41 as the test material, uniconazole (S3307, 50 mg·L-1) and 2-N, N- diethylamino ethyl caproate (DTA-6, 50 mg·L-1) were sprayed on leaves in the early flowering period of soybean. Through grey correlation analysis, the main factors affecting soybean yield were examined, and the differences of the light and heat utilization efficiency and soybean yield in two ecological conditions were compared. The regulation effects of chemical control technology on the light and heat utilization efficiency of soybean were explored. The results showed that the total surface radiation and ≥10 ℃ effective accumulated temperature were the main factors affecting soybean yield in both areas compared with rainfall and sunshine hours. The light and heat utilization efficiency from sowing to flowering period was significantly positively correlated with dry matter accumulation, and that from flowering to podding period was significantly positively correlated with dry matter accumulation per plant. There was a significant positive correlation between yield and dry matter accumulation, grain number per plant, grain mass per plant and 100-grain mass at seedling stage to podding stage. S3307 and DTA-6 could significantly improve light and heat utilization efficiency and soybean yield in both areas. S3307 showed the better regulation function to impact the light and heat utilization efficiency and yield than DTA-6 in both sites. In the two ecological areas of Jiusan and Lindian, spraying S3307 increased light utilization efficiency by 13.6% and 17.1%, and increased heat utilization efficiency by 14.1% and 17.2%, respectively. The yield by spraying S3307 was increased by 14.1% and 17.3% separately in Jiusan and Lindian. Therefore, it is the effective way to enhance resources utilization and achieve high-yield by using the reasonable chemical control technology.

Effect of nicorandil on early prognosis in patients undergoing cardiac valve replacement with cardiopulmonary bypass / 中华麻醉学杂志

Objective To evaluate the effect of nicorandil on early prognosis in patients undergoing cardiac valve replacement with cardiopulmonary bypass (CPB).Methods Forty American Society of Anesthesiologists physical status Ⅱ or Ⅳ patients,aged 18-64 yr,with New York Heart Association grade Ⅱ or Ⅲ,scheduled for elective cardiac valve replacement with CPB,were divided into 2 groups (n =20 each) using a random number table method:control group and nicorandil group.Nicorandil was intravenously infused at 10-60 μg · kg-1 · h-1 (3-15 ml/h) after anesthesia induction until the end of surgery in nicorandil group.Before anesthesia induction (To) and at 6,12,24,48 and 72 h after surgery (T1-5),and when the patients were discharged from hospital (T6),venous blood samples were obtained for determination of the concentrations of serum cardiac troponin I (cTnI) and brain natriuretic peptide.The events of myocardial ischemia or development of arrhythmia before and after surgery,development of defibrillation during restoration of heart beat,spontaneous heart beat,drug administration during restoration of heart beat,heart rhythm after restoration of heart beat,and the requirement for cardiovascular drugs during and after surgery were recorded.The mechanical ventilation time,duration of intensive care unit stay,and length of postoperative hospital stay were also recorded.Results Compared with control group,the concentrations of serum cTnI at T2,3 and brain natriuretic peptide at T2-6 were significantly decreased,the consumption of intraoperative norepinephrine and postoperative dobutamine was reduced,and the ventilation time and duration of intensive care unit stay were shortened (P＜0.05),and no significant change was found in the rate of defibrillation,restoration of spontaneous heart beat,requirement for drugs during restoration,heart rhythm after restoration or duration of postoperative hospital stay in nicorandil group (P ＞ 0.05).Conclusion Continuously infusing nicorandil during surgery can reduce myocardial injury and improve early prognosis in patients undergoing cardiac valve replacement with CPB.

Determination of 13 Kinds of Sulfonylurea Herbicides Residues in Aquatic Products by Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry / 分析化学

A sensitive method was proposed for determination of 13 kinds of sulfonylurea herbicides residues in aquatic products by solid phase extraction-ultra performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (SPE-UPLC-MS/MS). The edible part of carp, penaeus vannamei,crab,clam and sea cucumber were collected and homogenized. Analytes was extracted with ethyl acetate,and then cleaned up by MAX solid phase extraction column. Qualitation of the analytes was achieved with multiple reaction monitoring (MRM) and the external standard method was used for quantification. The 13 kinds of sulfonylurea herbicides showed good linearity in the concentration range of 5.0-100.0 μg/L respectively. The detection limits of the 13 analytes were 1.0 μg/kg, and the limit of quantification was 2.0 μg/kg. The average recoveries ranged from 75.4% to 118.3% with relative standard deviations from 2.1% to 14.5%. The 13 target analytes were not detected in grass carp,carp,sea cucumber,prawn,turbot of breeding and crabs from the market. The halosulfuron-methyl was detected in the edible tissues of crabs exposed to a 1.0 mg/L halosulfuron-methyl solution for 24,48 and 72 h,and the concentrations were 6.20, 12.1 and 16. 6 μg/kg respectively. The method can be stable and sensitive, and is applied to the determination of 13 kinds of sulfonylurea herbicides residues in aquatic products.