Endoscopic features of low-phospholipid-associated cholelithiasis syndrome: A retrospective cohort study.

BACKGROUND AND OBJECTIVE: LPAC (low phospholipid-associated cholelithiasis) syndrome is a rare genetic form of cholelithiasis. ERCP (endoscopic retrograde cholangiopancreatography) is often used to remove gallstones in the bile duct. No published data is available on the role of ERCP in LPAC syndrome. PATIENTS AND METHODS: In this retrospective cohort study, we included patients diagnosed with LPAC syndrome in a single tertiary referral center between 2009 and 2021. Our aim was to assess the frequency, indications, modalities, results, and complications of ERCP, as well as predictive factors for ERCP, in LPAC syndrome. Independent factors associated with ERCP occurrence were identified using a multivariable Cox regression analysis. RESULTS: ERCP was required in 31.2 % of the 269 patients included for analysis. Among patients who required ERCPs, 78.6 % had the procedure before diagnosis (i.e., starting UDCA). Most common indications were choledocholithiasis (53.6 %) and acute cholangitis (29.5 %). Post ERCP pancreatitis, perforation and bleeding rates were 7.2 %, 2.6 %, and 1.3 %, respectively. Age and history of cholelithiasis in first-degree relatives were associated with a higher risk of ERCP (Hazard-ratio [HR]=1.30 [95 %confidence-interval [CI] 1.04-1.62] and HR=1.88 [95 %CI 1.15-3.07] respectively). Female gender and UDCA intake ≥ 1 year were associated with a lower risk of ERCP (HR=0.49 [95 %CI 0.29-0.82] and HR=0.44 [95 %CI 0.22-0.90] respectively). Median follow-up was 10.8 years. CONCLUSION: One-third of patients with LPAC syndrome undergo sphincterotomy. However, most procedures are performed before diagnosis and UDCA is associated with a lower risk of endoscopic procedure. Earlier diagnosis and treatment with UDCA may further reduce the need for ERCP in patients with LPAC syndrome.

Dissociation along the principal Hugoniot of the Laser Mégajoule ablator material.

Glow discharge polymer hydrocarbon (GDP-CH) is used as the ablator material in inertial confinement fusion (ICF) capsules for the Laser Mégajoule and National Ignition Facility. Due to its fabrication process, GDP-CH chemical composition and structure differ from commercially available plastics and detailed knowledge of its properties in the warm dense matter regime is needed to achieve accurate design of ICF capsules. First-principles ab initio simulations of the GDP-CH principal Hugoniot up to 8 Mbar were performed using the quantum molecular dynamics (QMD) code abinit and showed that atomic bond dissociation has an effect on the compressibility. Results from these simulations are used to parametrize a quantum semiempirical model in order to generate a tabulated equation of state that includes dissociation. Hugoniot measurements obtained from an experiment conducted at the LULI2000 laser facility confirm QMD simulations as well as EOS modeling. We conclude by showing the EOS model influence on shock timing in a hydrodynamic simulation.

Impact of oxygen on the 300-K isotherm of Laser Megajoule ablator using ab initio simulation.

The ablator material for inertial confinement fusion (ICF) capsules on the Laser Mégajoule is a glow-discharge polymer (GDP) plastic. Its equation of state (EOS) is of primary importance for the design of such capsules, since it has direct consequences on shock timing and is essential to mitigate hydrodynamic instabilities. Using ab initio molecular dynamics (AIMD), we have investigated the 300-K isotherm of amorphous CH(1.37)O(0.08) plastic, whose structure is close to GDP plastic. The 300-K isotherm, which is often used as a cold curve within tabular EOS, is an important contribution of the EOS in the multimegabar pressure range. AIMD results are compared to analytic models within tabular EOS, pointing out large discrepancies. In addition, we show that the effect of oxygen decreases 300-K isotherm pressure by 10%-15%. The implication of these observations is the ability to improve ICF target performance, which is essential to achieve fusion ignition.

Experimental and ab initio investigations of microscopic properties of laser-shocked Ge-doped ablator.

Plastic materials (CH) doped with mid-Z elements are used as ablators in inertial confinement fusion (ICF) capsules and in their surrogates. Hugoniot equation of state (EOS) and electronic properties of CH doped with germanium (at 2.5% and 13% dopant fractions) are investigated experimentally up to 7 Mbar using velocity and reflectivity measurements of shock fronts on the GEKKO laser at Osaka University. Reflectivity and temperature measurements were updated using a quartz standard. Shocked quartz reflectivity was measured at 532 and 1064 nm. Theoretical investigation of shock pressure and reflectivity was then carried out by ab initio simulations using the quantum molecular dynamics (QMD) code abinit and compared with tabulated average atom EOS models. We find that shock states calculated by QMD are in better agreement with experimental data than EOS models because of a more accurate description of ionic structure. We finally discuss electronic properties by comparing reflectivity data to a semiconductor gap closure model and to QMD simulations.

Change in inertial confinement fusion implosions upon using an ab initio multiphase DT equation of state.

Improving the description of the equation of state (EOS) of deuterium-tritium (DT) has recently been shown to change significantly the gain of an inertial confinement fusion target [S. X. Hu et al., Phys. Rev. Lett. 104, 235003 (2010)]. Here we use an advanced multiphase EOS, based on ab initio calculations, to perform a full optimization of the laser pulse shape with hydrodynamic simulations starting from 19 K in DT ice. The thermonuclear gain is shown to be a robust estimate over possible uncertainties of the EOS. Two different target designs are discussed, for shock ignition and self-ignition. In the first case, the areal density and thermonuclear energy can be recovered by slightly increasing the laser energy. In the second case, a lower in-flight adiabat is needed, leading to a significant delay (3 ns) in the shock timing of the implosion.