Observation of rotational coherence in an excited state of CO. Opt Lett 2021;46:3893-3896. [PMID: 34388768 DOI: 10.1364/ol.432315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

The vacuum ultraviolet (VUV) radiation is generated in the strong-field-ionized CO molecules through 2+1 resonance excitation with two-color femtosecond laser pulses. When scanning the relative delay between two pump pulses, the rotational-resolved VUV radiations show periodic oscillations lasting as long as 500 ps. Fourier analysis reveals that these oscillations correspond to rotational beat frequencies of the A²Π_i state of CO⁺, which is the result of multi-channel interference during the resonant excitation process. High resolution of Fourier transform spectra up to 0.067cm^-1 allows us to obtain the fine energy levels of the A²Π_i state. The theoretical calculation is in good agreement with the experimental observation. This work reveals the rotational coherence of the ionic excited state and shows the prospect of rotational coherence spectroscopy in measuring fine structures of molecular ions.

T-tube vs no T-tube for biliary tract reconstruction in adult orthotopic liver transplantation: An updated systematic review and meta-analysis

BACKGROUND

Whether to use a T-tube for biliary anastomosis during orthotopic liver transplantation (OLT) remains a debatable question. Some surgeons chose to use a T-tube because they believed that it reduces the incidence of biliary strictures. Advances in surgical techniques during the last decades have significantly decreased the overall incidence of postoperative biliary complications. Whether using a T-tube during OLT is still associated with the reduced incidence of biliary strictures needs to be re-evaluated.

AIM

To provide an updated systematic review and meta-analysis on using a T-tube during adult OLT.

METHODS

In the electronic databases MEDLINE, PubMed, Scopus, ClinicalTrials.gov, the Cochrane Library, the Cochrane Hepato-Biliary Group Controlled Trails Register, and the Cochrane Central Register of Controlled Trials, we identified 17 studies (eight randomized controlled trials and nine comparative studies) from January 1995 to October 2020. The data of the studies before and after 2010 were separately extracted. We chose the overall biliary complications, bile leaks or fistulas, biliary strictures (anastomotic or non-anastomotic), and cholangitis as outcomes. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to describe the results of the outcomes. Furthermore, the test for overall effect (Z) was used to test the difference between OR and 1, where P ≤ 0.05 indicated a significant difference between OR value and 1.

RESULTS

A total of 1053 subjects before 2010 and 1346 subjects after 2010 were included in this meta-analysis. The pooled results showed that using a T-tube reduced the incidence of postoperative biliary strictures in studies before 2010 (P = 0.012, OR = 0.62, 95%CI: 0.42-0.90), while the same benefit was not seen in studies after 2010 (P = 0.60, OR = 0.76, 95%CI: 0.27-2.12). No significant difference in the incidence of overall biliary complications (P = 0.37, OR = 1.41, 95%CI: 0.66-2.98), bile leaks (P = 0.89, OR = 1.04, 95%CI: 0.63-1.70), and cholangitis (P = 0.27, OR = 2.00, 95%CI: 0.59-6.84) was observed between using and not using a T-tube before 2010. However, using a T-tube appeared to increase the incidence of overall biliary complications (P = 0.049, OR = 1.49, 95%CI: 1.00-2.22), bile leaks (P = 0.048, OR = 1.91, 95%CI: 1.01-3.64), and cholangitis (P = 0.02, OR = 7.21, 95%CI: 1.37-38.00) after 2010. A random-effects model was used in biliary strictures (after 2010), overall biliary complications (before 2010), and cholangitis (before 2010) due to their heterogeneity (I² = 62.3%, 85.4%, and 53.6%, respectively). In the sensitivity analysis (only RCTs included), bile leak (P = 0.66) lost the significance after 2010 and a random-effects model was used in overall biliary complications (before 2010), cholangitis (before 2010), bile leaks (after 2010), and biliary strictures (after 2010) because of their heterogeneity (I² = 92.2%, 65.6%, 50.9%, and 80.3%, respectively).

CONCLUSION

In conclusion, the evidence gathered in our updated meta-analysis showed that the studies published in the last decade did not provide enough evidence to support the routine use of T-tube in adults during OLT.