Single-port laparoscopy-assisted vaginal repair of a cesarean scar defect: a single-center retrospective study

Background:The incidence of uterine cesarean scar defect(niche)is high,and some patients require surgery.Single-port laparoscopy can reduce post-operative pain,and provide better cosmetic effects.This study was performed to evaluate the safety and superiority of single-port laparoscopy-assisted vaginal repair of uterine cesarean scar defect(niche)in women after cesarean section.Methods:This study included 74 patients who were diagnosed with uterine cesarean niche at the Shanghai First Maternity and Infant Hospital from January 2013 to June 2015.Thirty-seven patients underwent single-port laparoscopy-assisted vaginal surgery as the case group,and the remaining patients underwent vaginal repair surgery as the control group.We collected data from the inpatient and follow-up medical records.The clinical characteristics of these two groups were compared.The odds ratios and 95%confidential intervals were calculated for each variable by univariate and multivariate analyses.Results:Patients who underwent single-port laparoscopy-assisted vaginal repair had a significantly longer operation time(2.3[2.0-2.7]vs.2.0[1.6-2.3]h,P=0.015),shorter gas passage time(1.2[1.0-1.5]vs.1.7[1.0-2.0]days,P=0.012),shorter hospital stay(3.1[3.0-4.0]vs.4.5[4.0-6.0]days,P=0.019),and fewer complications(0 vs.4 cases).Univariate analysis showed that depth of the niche(P=0.021)the mild adhesiolysis score(P=0.035)and moderate adhesiolysis score(P=0.013)were associated with the bladder injury.Multivariate analysis showed that the moderate adhesiolysis score(P=0.029;95%confidence interval,1.318-3.526)was the strongest independent predictor of bladder injury.Conclusion:This study confirmed the safety and superiority of single-port laparoscopy-assisted vaginal repair of uterine cesarean scars.

Characterization and Thermodynamics of Al_2O_3-MnO-SiO_2(-MnS)Inclusion Formation in Carbon Steel Billet

A method to extract inclusion particles from solid steel by electrolysis with organic electrolyte solution was introduced; meanwhile, thermodynamics of inclusion formation was calculated using FaetSage software. The results showed that there were two kinds of inclusions in the billet, i.e. Al2O3-MnO-SiO2-MnS （AMS-MnS） and Al2O3- MnO-SiO2 （AMS）. Most of AMS-MnS inclusion particles, with diameter of 10--30 μm, showed three-layer structures： SiO2-rich core with a small quantity of Mn, intermediate AMS layer, and MnS outer layer containing small quanti- ties of A1 and O. Most AMS inclusion particles were 50--90 μm and exhibited homogeneous composition. Thermo- dynamic results indicated that SiO2-rich core could form firstly by Si reacting with O in molten steel at temperatures above 1 923 K during Si-Fe alloy addition, and then, the SiO2-rich core could react with Mn and Al to form liquid AMS enveloping the SiO2 rich core at 1823- 1873 K. MnS began to precipitate from AMS when temperature reached 1 728 K. Liquid AMS could form by coupled reaction among Si, Mn, Al and O in molten steel.

Composition evolution and deformation of different non-metallic inclusions in a bearing steel during hot rolling

The composition evolution and deformation of different non-metallic inclusions in a bearing steel during hot rolling were investigated by the automatic detection and the improved non-aqueous electrolysis method.Manganese sulfide,MnS–TiN,and liquid CaO–Al_(2)O_(3) inclusions were elongated while TiN and MgO-Al_(2)O_(3) were fractured during hot rolling.The CaS–MnS phase in the MgO–Al_(2)O_(3)–CaS–MnS inclusion was separated from the inclusion,leading to the formation of CaS–MnS type clusters.Meanwhile,the CaS and MnS contents in oxide-containing inclusions decreased while the MgO and Al_(2)O_(3) contents increased after hot rolling.The deformability of different inclusions in the bearing steel was quantitatively compared and discussed.

A Multi-step Thermodynamic Model for Alumina Formation during Aluminum Deoxidation in Fe–O–Al Melt

Based on the two-step nucleation mechanism, a multi-step thermodynamic model for alumina inclusion for- mation during aluminum deoxidation process was proposed in Fe-O-Al melt. Thermodynamic properties of metastable intermediates including （Al2O3）n clusters for prenucleation and α-Al2O3 nanoparticle for growth process were calculated using density functional theory. Furthermore, Gibbs free energy change of forming the intermediate by reaction between the dissolved aluminum （Al） and oxygen （O） in the melt was calculated. The results indicated that the thermodynamics of （Al2O3）n at steelmaking temperature are dependent on their structures, while that of α-Al2O3 nanoparticle are dependent on their size. The nuclei of α-Al2O3 which was originated from （Al2O3）n aggregated under a high supersaturation ratio of Al and O（Rs） in the melt. There existing excess oxygen because of the low Rs, but the secondary inclusions will be formed during the cooling process due to the excess oxygen. The nuclei lager than 20 nm can grow up spontaneously and instantaneously into primary inclusions because of thermodynamic drive. It is difficult to control the size of α-Al2O3 to be less than 20 nm, in the aluminum deoxidation process of the current conditions of steelmaking.

Construction of supramolecular nanofibers through electrostatic interaction between perylene and cholesterol derivatives

The self-assembly of cationic perylene diimide （PDI） and anionic cholesterol derivatives （CHOL） was conveniently achieved by the electrostatic attraction and π-π stacking interactions, exhibiting the weft-defined supramolecular nanofibers ranging from hundreds of nanometers to micron dimension.

Effect of Mg addition on TiN inclusions in GCr15 bearing steel

Compared with the original GCr15 bearing steel,TiN inclusions are greatly reduced by the effect of Mg addition,and many different types of non-metallic Mg-containing inclusions were observed in Mg-treated GCr15 bearing steel which includes MgO,MgS·MnS,MgO–MgS·MnS,MgAl_(2)O_(4)–MgS·MnS,MgO–TiN,MgS·MnS–TiN,and MgO–MgS·MnS–TiN.The inclusion size distribution based on automatic inclusion analysis software shows that the number of inclusion with the size ranging from 1 to 3μm increases obviously because a large amount of MgO,MgS·MnS,TiN inclusions containing Mg with smaller sizes are massively generated.In situ observation on the experimental steel by high-temperature confocal laser scanning microscopy confirms that MgO can provide nucleation sites for TiN.In addition,the MgS·MnS and MgO–MgS·MnS inclusions can also provide positions for the nucleation of TiN.Thermodynamic calculations indicate that after Mg addition to liquid steel,a large number of fine MgO inclusions are generated in the liquid steel because of the strong reactivity of Mg and O.At the same time,MgS precedes TiN precipitates in the solid–liquid two-phase region;thus,MgO and MgS·MnS can provide sites for TiN nucleation.At last,two possible formation pathways for the above various TiN inclusions containing Mg are discussed.

Effect of trace Si on MgO·Al_(2)O_(3)inclusion in ultra-low-carbon steel

There are four types of Mg–Al–Si–O inclusions observed in the Mg-treated Al-deoxidized ultra-low-carbon steel con-taining trace Si,including SiO_(2),2MgO·SiO_(2),3Al_(2)O_(3)·2SiO_(2),and 2MgO·Al_(2)O_(3)·5SiO_(2)and their composite inclusions.Using FactSage,the phase relationship of Mg–Al–Si–O system at 1473–2073 K was calculated using FactSage software,and the change in Si content can change the stable region range of different Mg–Al–Si–O-based inclusions.Based on the types of inclusions observed experimentally,the formation pathways of inclusions were predicted and a kinetic model was established to describe the formation process of the xMgO·yAl_(2)O_(3)–Mg–Al–Si–O and xAl_(2)O_(3)·ySiO_(2)–Mg–Al–Si–O inclusions.