Garnet secondary ion mass spectrometry oxygen isotopes reveal crucial roles of pulsed magmatic fluid and its mixing with meteoric water in lode gold genesis.

SignificanceThere is a common consensus that lode gold deposits mostly precipitated from metamorphic fluids via fluid boiling and/or fluid-rock interaction, but whether magmatic hydrothermal fluids and the mixing of such fluids with an external component have played a vital role in the formation of lode gold deposits remains elusive. We use garnet secondary ion mass spectrometry oxygen isotope analysis to demonstrate that the world-class Dongping lode gold deposit has been formed by multiple pulses of magmatic hydrothermal fluids and their mixing with large volumes of meteoric water. This study opens an opportunity to tightly constrain the origin of lode gold deposits worldwide and other hydrothermal systems that may have generated giant ore deposits in the Earth's crust.

[Value of identification of cystic duct, common bile duct, and common hepatic duct in prevention of bile duct injury during laparoscopic cholecystectomy].

OBJECTIVE: To explore effective method to avoid iatrogenic bile duct injury during laparoscopic cholecystectomy (LC). METHODS: 10 492 patients underwent LC from May 1996 to May 2006, 8566 of them were treated by the method to identify the cystic duct, common hepatic duct, and common bile duct during LC (tri-duct method group), and the left 1926 cases whose cystic duct failed to be exposed easily were treated with the method to identify at least two of the 4 structures (cystic lymph node, Hartmann's pouch, cystic artery, and emptiness of cystic triangle) so as to help identify the cystic duct (tri-duct plus tri-structure group). The operating time, amount of blood loss, open conversion rate, and morbidity were compared between these 2 groups. RESULTS: No cases of bile leakage or jaundice because of accidental injury of bile duct were found. The operating time of the tri-duct plus tri-structure group was (28 +/- 12) (15 - 52) min, significantly shorter than that of the tri-duct group [(38 +/- 16) (15 - 92) min, P < 0.05]. The open conversion rate of the tri-duct plus tri-structure group was 1.8%, significantly lower than that of the tri-duct group (8.7%, P < 0.05). There were no significant difference in the amount of blood loss and morbidity between the two groups (both P > 0.05). CONCLUSION: The tri-structure method can not only confirm the cystic duct correctly, thus preventing iatrogenic bile duct injury, but also shorten the operating time and reduce the open conversion ratio during LC.