Glutamine-supplemented total parenteral nutrition attenuates plasma interleukin-6 in surgical patients with lower disease severity

AIM: To evaluate whether the effect of Gln dipeptideenriched total parenteral nutrition (TPN) on postoperative cytokine alteration depended on the disease severity of surgical patients.METHODS: Forty-eight patients with major abdominal surgery were allocated to two groups to receive isonitrogenous (0.228 g nitrogen/kg per d) and isocaloric(30 kcal/kg per d) TPN for 6 d. Control group (Conv)using conventional TPN solution received 1.5 g amino adds/kg per day, whereas the test group received 0.972 g amino acids/kg per day and 0.417 g L-alanyl-L-glutamine(Ala-Gln)/kg per day. Blood samples were collected on d 1 and d 6 postoperatively for plasma interleukin (IL)-2,IL-6, IL-8, and interferon (IFN)-γ analysis.RESULTS: Plasma IL-2 and IFN-γ were not detectable.IL-6 concentrations were significantly lower on the 6th postoperative day in the Ala-Gln group than those in the Conv group in patients with APACHE Ⅱ≤6, whereas no difference was noted in patients with APACHE Ⅱ＞6. There was no difference in IL-8 levels between the two groups.No difference in cumulative nitrogen balance was observed on d 2-5 after the operation between the two groups(Ala-Gln -3.2±1.6 g vs Conv -6.5±2.7 g). A significant inverse correlation was noted between plasma IL-6 levels and cumulative nitrogen balance postoperatively in the Ala-Gln group, whereas no such correlation was observed in the Conv group.CONCLUSION: TPN supplemented with Gln dipeptide had no effect on plasma IL-8 levels after surgery. However,Gln supplementation had a beneficial effect on decreasing systemic IL-6 production after surgery in patients with low admission illness severity, and lower plasma IL-6 may improve nitrogen balance in patients with abdominal surgery when Gln was administered.

Experimental investigation on dynamic response and damage models of circular RC columns subjected to underwater explosions

Reinforced concrete(RC) columns are widely used as supporting structures for high-piled wharfs.The study of damage model of a RC column due to underwater explosion is a critical issue to assess the wharfs antiknock security.In this study,the dynamic response and damage model of circular RC columns subjected to underwater explosions were investigated by means of scaled-down experiment models.Experiments were carried out in a 10.0 m diameter tank with the water depth of 2.25 m,under different explosive quantities(0.025 kg-1.6 kg),stand-off distances(0.0 m-7.0 m),and detonation depths(0.25 m-2.0 m).The shock wave load and dynamic response of experiment models were measured by configuring sensors of pressure,acceleration,strain,and displacement.Then,the load distribution characteristics,time history of test data,and damage models related to present conditions were obtained and discussed.Three damage models,including bending failure,bending-shear failure and punching failure,were identified.In addition,the experie nce model of shock wave loads on the surface of a RC column was proposed for engineering application.

Experimental investigations of mechanical and reaction responses for drop-weight impacted energetic particles

Low-velocity drop-weight impact experiments on individual and multiple Cyclotetramethylene tetranitramine (HMX) energetic particles were performed using a modified drop-weight machine equipped with high-speed photography components. Multiple particles experienced more severe burning reactions than an individual particle. Comparisons between impacted salt and HMX particle show that jetting in HMX is mainly due to the motion of fragmented particles driven by gaseous reaction products. Velocity of jetting, flame propagation, and area expansion were measured via image processing, making it possible to quantify the chemical reaction or mechanical deformation violence at different stages.

Feng Ligand:Privileged Chiral Ligand in Asymmetric Catalysis

Catalysts and ligands possessing the great ability to tolerate over a wide range of mechanistically unrelated reactions are remarked as"privileged",which are rather scarce but extremely meaningful in asymmetric catalysis.Feng and co-workers have developed a library of conformationally flexible,C2-symmetric N,N'-dioxide amide compounds with original design and featured structure(named as Feng ligand now).They were initially reported as chiral organocatalysts in 2005 and have been further developed as a new class of privileged chiral ligands since 2006.Tremendous success,including versatile coordination chemistry with plenty of metal sources(main-group metals,transition metals,and rare-earth metals),a truly broad scope of asymmetric reactions(more than 50 types),diverse areas of catalysis(organocatalysis,Lewis-acid catalysis,bimetallic relay catalysis,and photocatalysis),numerous synthetic applications of bioactive compounds,has been achieved using Feng N,N'-dioxide.Besides,they demonstrate that chiral ligands with conformationally flexible property can offer excellent chiral environment as well,which challenges the conventional idea preferring rigid structures in the design of chiral ligands.Herein,we briefly introduced the discovery of Feng ligand and the millstones during the development.We also covered the successful applications of Feng ligand by other scientists as well as novel chiral ligands inspired by them.