Epoxy resin,characterized by prominent mechanical and electric-insulation properties,is the preferred material for packaging power electronic devices.Unfortunately,the efficient recycling and reuse of epoxy materials ...Epoxy resin,characterized by prominent mechanical and electric-insulation properties,is the preferred material for packaging power electronic devices.Unfortunately,the efficient recycling and reuse of epoxy materials with thermally cross-linked molecular structures has become a daunting challenge.Here,we propose an economical and operable recycling strategy to regenerate waste epoxy resin into a high-performance material.Different particle size of waste epoxy micro-spheres(100–600μm)with core-shell structure is obtained through simple mechanical crushing and boron nitride surface treatment.By using smattering epoxy monomer as an adhesive,an eco-friendly composite material with a“brick-wall structure”can be formed.The continuous boron nitride pathway with efficient thermal conductivity endows eco-friendly composite materials with a preeminent thermal conductivity of 3.71 W m^(−1)K^(−1)at a low content of 8.5 vol%h-BN,superior to pure epoxy resin(0.21 W m^(−1)K^(−1)).The composite,after secondary recycling and reuse,still maintains a thermal conductivity of 2.12 W m^(−1)K^(−1)and has mechanical and insulation properties comparable to the new epoxy resin(energy storage modulus of 2326.3 MPa and breakdown strength of 40.18 kV mm^(−1)).This strategy expands the sustainable application prospects of thermosetting polymers,offering extremely high economic and environmental value.展开更多
Sperm DNA damage is recognized as an important biomarker of male infertility. To investigate this, sperm DNA damage was assessed by the sperm chromatin dispersion （SCD） test in semen and motile spermatozoa harvested...Sperm DNA damage is recognized as an important biomarker of male infertility. To investigate this, sperm DNA damage was assessed by the sperm chromatin dispersion （SCD） test in semen and motile spermatozoa harvested by combined density gradient centrifugation （DGC） and swim-up in 161 couples undergoing in vitro fertilization （IVF）. Semen analysis and sperm DNA damage results were compared between couples who did or did not achieve pregnancy. The sperm DNA damage level was significantly different between the two groups （P 〈 0.05） and was negatively correlated with IVF outcomes. Logistic regression analysis confirmed that it was an independent predictor for achieving clinical pregnancy. The effects of different levels of sperm DNA damage on IVF outcomes were also compared. There were significant differences in day 3 embryo quality, blastocyst formation rate, and implantation and pregnancy rates （P 〈 0.05）, but not in the basic fertilization rate between the two groups. Thus, sperm DNA damage as measured by the SCD appears useful for predicting the clinical pregnancy rate following IVF.展开更多
基金supported by the National Natural Science Foundation of China(Nos.51977084 and 52307025).
文摘Epoxy resin,characterized by prominent mechanical and electric-insulation properties,is the preferred material for packaging power electronic devices.Unfortunately,the efficient recycling and reuse of epoxy materials with thermally cross-linked molecular structures has become a daunting challenge.Here,we propose an economical and operable recycling strategy to regenerate waste epoxy resin into a high-performance material.Different particle size of waste epoxy micro-spheres(100–600μm)with core-shell structure is obtained through simple mechanical crushing and boron nitride surface treatment.By using smattering epoxy monomer as an adhesive,an eco-friendly composite material with a“brick-wall structure”can be formed.The continuous boron nitride pathway with efficient thermal conductivity endows eco-friendly composite materials with a preeminent thermal conductivity of 3.71 W m^(−1)K^(−1)at a low content of 8.5 vol%h-BN,superior to pure epoxy resin(0.21 W m^(−1)K^(−1)).The composite,after secondary recycling and reuse,still maintains a thermal conductivity of 2.12 W m^(−1)K^(−1)and has mechanical and insulation properties comparable to the new epoxy resin(energy storage modulus of 2326.3 MPa and breakdown strength of 40.18 kV mm^(−1)).This strategy expands the sustainable application prospects of thermosetting polymers,offering extremely high economic and environmental value.
文摘Sperm DNA damage is recognized as an important biomarker of male infertility. To investigate this, sperm DNA damage was assessed by the sperm chromatin dispersion （SCD） test in semen and motile spermatozoa harvested by combined density gradient centrifugation （DGC） and swim-up in 161 couples undergoing in vitro fertilization （IVF）. Semen analysis and sperm DNA damage results were compared between couples who did or did not achieve pregnancy. The sperm DNA damage level was significantly different between the two groups （P 〈 0.05） and was negatively correlated with IVF outcomes. Logistic regression analysis confirmed that it was an independent predictor for achieving clinical pregnancy. The effects of different levels of sperm DNA damage on IVF outcomes were also compared. There were significant differences in day 3 embryo quality, blastocyst formation rate, and implantation and pregnancy rates （P 〈 0.05）, but not in the basic fertilization rate between the two groups. Thus, sperm DNA damage as measured by the SCD appears useful for predicting the clinical pregnancy rate following IVF.
