In view of the unclear cause of perfluorocarbons(PFCs)emission in the anode effect stage of aluminum electrolysis,the microscopic formation mechanism of PFCs was studied by density functional theory calculation and X-...In view of the unclear cause of perfluorocarbons(PFCs)emission in the anode effect stage of aluminum electrolysis,the microscopic formation mechanism of PFCs was studied by density functional theory calculation and X-ray photoelectron spectroscopy(XPS).It is found that the discharge of fluorine containing anions([F]−)on carbon anode first causes the substitution of C—H by C—F and further results in the saturation of aromatic C—C bonds,leading to the appearance of—CF_(3)or—C_(2)F_(5)group through six-carbon-ring opening.Elimination of—CF_(3)and—C_(2)F_(5) with F atom could be a likely mechanism of CF_(4) and C_(2)F_(6) formation.XPS results confirm that different types of—CF_(x) group can be formed on anode surface during electrolysis,and the possibility that[F]−discharges continuously at the C edge and finally forms different C—F bonds in quantum mechanical calculation was verified.展开更多
BACKGROUND 45,X/46,XY mosaicism is a rare chromosomal abnormality with a wide range ofphenotypes in both males and females, from normal individuals with differentdegrees of genital ambiguity to those who show signs of...BACKGROUND 45,X/46,XY mosaicism is a rare chromosomal abnormality with a wide range ofphenotypes in both males and females, from normal individuals with differentdegrees of genital ambiguity to those who show signs of Turner’s syndrome.More rarely, cases of 45,X/46,XY mosaicism with a normal-appearing malephenotype are not found until a chromosome test is performed to investigate thecause of male infertility.CASE SUMMARY In this study, a 29-year-old male patient with complete azoospermia is reported.Chromosomal analyses of his lymphocytes revealed the karyotype 45,X[93%]/46,X,+mar(Y)[7%]. In addition, Y chromosome-specific markers, such as SRY,ZFY, AZFa, AZFb and AZFc, were not observed in his blood DNA according tomultiplex polymerase chain reaction test. A literature review identified several45,X/46,XY cases with a normal-appearing male phenotype, most of whom werediagnosed during infertility investigation. However, the present case is the firstSRY-negative 45,X/46,XY male case diagnosed during a premarital medicalexamination.CONCLUSION This finding further suggests that sex determination is a complex processregulated by multiple genetic and environmental factors.展开更多
基金the financial supports from the National Natural Science Foundation of China(Nos.51974373,51874365,62133016)the Major Scientific and Technological Innovation Projects of Shandong Province,China(No.2019JZZY020123)the Fundamental Research Funds for the Central Universities of Central South University,China(No.2019zzts242)。
文摘In view of the unclear cause of perfluorocarbons(PFCs)emission in the anode effect stage of aluminum electrolysis,the microscopic formation mechanism of PFCs was studied by density functional theory calculation and X-ray photoelectron spectroscopy(XPS).It is found that the discharge of fluorine containing anions([F]−)on carbon anode first causes the substitution of C—H by C—F and further results in the saturation of aromatic C—C bonds,leading to the appearance of—CF_(3)or—C_(2)F_(5)group through six-carbon-ring opening.Elimination of—CF_(3)and—C_(2)F_(5) with F atom could be a likely mechanism of CF_(4) and C_(2)F_(6) formation.XPS results confirm that different types of—CF_(x) group can be formed on anode surface during electrolysis,and the possibility that[F]−discharges continuously at the C edge and finally forms different C—F bonds in quantum mechanical calculation was verified.
文摘BACKGROUND 45,X/46,XY mosaicism is a rare chromosomal abnormality with a wide range ofphenotypes in both males and females, from normal individuals with differentdegrees of genital ambiguity to those who show signs of Turner’s syndrome.More rarely, cases of 45,X/46,XY mosaicism with a normal-appearing malephenotype are not found until a chromosome test is performed to investigate thecause of male infertility.CASE SUMMARY In this study, a 29-year-old male patient with complete azoospermia is reported.Chromosomal analyses of his lymphocytes revealed the karyotype 45,X[93%]/46,X,+mar(Y)[7%]. In addition, Y chromosome-specific markers, such as SRY,ZFY, AZFa, AZFb and AZFc, were not observed in his blood DNA according tomultiplex polymerase chain reaction test. A literature review identified several45,X/46,XY cases with a normal-appearing male phenotype, most of whom werediagnosed during infertility investigation. However, the present case is the firstSRY-negative 45,X/46,XY male case diagnosed during a premarital medicalexamination.CONCLUSION This finding further suggests that sex determination is a complex processregulated by multiple genetic and environmental factors.
