The stable -acetyl analogues of biologically important 9--acetylated b-series gangliosides including 9NAc-GD3, 9NAc-GD2, 9NAc-GD1b, and 9NAc-GT1b were chemoenzymatically synthesized from a GM3 sphingosine. Two chemoenzymatic methods using either 6-azido-6-deoxy--acetylmannosamine (ManNAc6N) as a chemoenzymatic synthon or 6-acetamido-6-deoxy--acetylmannosamine (ManNAc6NAc) as an enzymatic precursor for 9-acetamido-9-deoxy--acetylneuraminic acid (Neu5Ac9NAc) were developed and compared for the synthesis of 9NAc-GD3. The latter method was found to be more efficient and was used to produce the desired 9--acetylated glycosylsphingosines.
View Article and Find Full Text PDFDue to their simplicity and reliability, random-pattern skin flaps are commonly utilized in surgical reconstruction to repair cutaneous wounds. However, the post-operative necrosis frequently happens because of the ischemia and high-level of oxidative stress of random skin flaps, which can severely affect the healing outcomes. Earlier evidence has shown promising effect of Nuciferine (NF) on preventing hydrogen peroxide (HO)-induced fibroblast senescence and ischemic injury, however, whether it can function on promoting ischemic flap survival remains unknown.
View Article and Find Full Text PDFProtein N-glycosylation is a common post-translational modification that plays significant roles on the structure, property, and function of glycoproteins. Due to N-glycan heterogeneity of naturally occurring glycoproteins, the functions of specific N-glycans on a particular glycoprotein are not always clear. Glycoprotein in vitro N-glycan engineering using purified recombinant enzymes is an attractive strategy to produce glycoproteins with homogeneous N-glycoforms to elucidate the specific functions of N-glycans and develop better glycoprotein therapeutics.
View Article and Find Full Text PDFEnergy storage technology is the key to achieving a carbon emission policy. The purpose of the paper is to improve the overall performance of the combined cooling, heating and power-ground source heat pump (CCHP-GSHP) system by the battery. A new operation strategy (the two-point operation) is proposed by controlling the power generation unit work.
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