Uterus-Preserving Treatment for Placenta Percreta by Reconstruction of the Lower Uterine Segment Using Wave Compression Suture: A Retrospective Cohort Study

Purpose To observe the hemostatic efficacy of reconstructing the lower uterine segment by wave compression sutures (WCSs) in patients with placenta previa who underwent cesarean section (CS). Methods Retrospective analysis the medical records with placenta previa underwent WCS at the West China Second University Hospital of Sichuan University.One-hundred-and-twenty-three women who received WCSs as the first uterine suture technique from January 1, 2016, to December 31, 2020, were included in this study. The hemostatic effect of WCS was compared according to the type of placenta previa and the intraoperative situation. All patients were followed up after CS. Results The hemostatic effect during CS and postpartum hemorrhage were observed. Seventy-two (58.5%) patients successfully achieved hemostasis without further intervention. Fifty-one (41.5%) cases required additional uterine artery ligation (UAL), cervical hanging maneuver (CHM), and Bakri tamponade. Seventy-nine cases exhibited thin anterior walls and lower uterine atony after placental dissection; of these, 72 (91.1%) obtained hemostasis by WCS. No patient required repeat laparotomy or hysterectomy. There were no complications attributable to the WCS following surgery. Among the five patients who had a second pregnancy, no intrauterine adhesions or abnormal uterine morphologies were caused by WCS. No ectopic or incision pregnancies occurred. Conclusions Reconstruction of the lower uterine segment by WCS is a suitable technique for patients with thin anterior walls and uterine atony of the lower uterine segment along with placenta previa. WCS is easy to perform, effective, and safe.

FUNDAMENTALS OF TECHNOLOGY FOR OBTAINING WEAR-RESISTANT HARD ALLOY POWDER COATINGS BY EXPLOSION

An overview of the results of an experimental study of the effect of the type and content of the metal binder, the parameters of shock-wave compression and subsequent heating on the formation of hard alloys and coatings from them during the explosive treatment of CrC-Ti powder mixtures on steel substrates is presented, the mechanism of wear and antifriction properties of the obtained materials is described.

Comparison of stress orientation indicators in Chicxulub’s peak ring: Kinked biotites, basal PDFs, and feather features

ABSTRACT During hypervelocity impacts, target rocks are subjected to shock wave compression with high pressures and differential stresses. These differential stresses cause microscopic shear-induced deformation, which can be observed in the form of kinking, twinning, fracturing, and shear faulting in a range of minerals. The orientation of these shear-induced deformation features can be used to constrain the maximum shortening axis. Under the assumption of pure shear deformation, the maximum shortening axis is parallel to the maximum principal axis of stress, σ1, which gives the propagation direction of the shock wave that passed through a rock sample. In this study, shocked granitoids cored from the uppermost peak ring of the Chicxulub crater (International Ocean Discovery Program [IODP]/International Continental Drilling Project [ICDP] Expedition 364) were examined for structures formed by shearing. Orientations of kink planes in biotite and basal planar deformation features (PDFs) in quartz were measured with a U-stage and compared to a previous study of feather feature orientations in quartz from the same samples. In all three cases, the orientations of the shortening axis derived from these measurements were in good agreement with each other, indicating that the shear deformation features all formed in an environment with similar orientations of the maximum principal axis of stress. These structures formed by shearing are useful tools that can aid in understanding the deformational effects of the shock wave, as well as constraining shock wave propagation and postshock deformation during the cratering process.

Магнитные превращения и полиморфный переход ферромагнитных сталей при ударно-волновом нагружении

A.M. Molodets A.A. Golyshev, A.N. Emelyanov, A.A. Kozlov The method for recording magnetic transformation is presented for ferromagnetic steels under shock-wave loading. The operation of the magnetic transformation gauge is considered under shock-wave loading at the polymorphic transition pressure of ARMCO iron and 15Kh2NMFA (in Russian) nuclear reactors case steel. It is shown that the pressures of magnetic transformations of steels correlate with the pressures of polymorphic transitions of these shocked steels. Comparison of gauge readings and parameters of polymorphic transitions was performed for iron and steel during shock-wave compression and subsequent unloading

RESEARCH OF THE MECHANISM OF SEALING POWDER MIXTURES BASED ON SILICON CARBIDE IN EXPLOSIVE PRESSING

The effects of the metal binder content and parameters of shock-wave compression on the compaction of SiC-Ti powder mixtures under explosive loading were investigated; microstructure of the obtained materials; The prevailing mechanisms of compaction of powder mixtures of silicon carbide with titanium during explosive pressing are revealed.