Retroperitoneal para-aortic ectopic pregnancies: A review of reported cases

Objective: To gain insights into the diagnosis and treatment of retroperitoneal para-aortic ectopic pregnancies (RPEP). Methods: We conducted a review of the existing literature from the web of science, PubMed, and CNKI using the search terms ''ectopic pregnancy'' and ''retroperitoneal.'' The present review follows the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Results: After applying the inclusion and exclusion criteria, we included a total of 54 relevant works, encompassing 55 cases. The studies have revealed that a history of artificial abortion, embryo transfer, salpingectomy, and uterine cavity operation, accounted for 65.5 ​% (36/55) of the cases. Typical symptoms of RPEP include abdominal pain (43.6 ​%, 24/55) and vaginal bleeding (36.4 ​%, 20/55), with only 32.7 ​% (18/55) of cases being asymptomatic. The most common sites of RPEP are the abdominal aorta and the inferior vena cava (74.5 ​%, 41/55). There were no statistically significant differences in the incidence of acute abdomen, diameter of the pregnancy sac, number of surgeries, and the time for postoperative hCG to normalize in different pregnant site. The most effective imaging examination for RPEP was found to be abdominal ultrasound (72.7 ​%, 40/55), and the most commonly used treatment method was laparoscopy surgery (55.3 ​% ,21/38). Conclusion: It is crucial to consider the possibility of RPEP when a pregnancy mass cannot be located during routine examinations. Expanding the scope of the scan may significantly expedite diagnosis and treatment

Research on Preparation and Properties of Coated Polyether Silicone Microencapsulation Based on Polystyrene

By the method of interfacial polymerization, the novel microcapsules were prepared with polystyrene as wall material and polyether silicone as core material. In order to demonstrate the morphologies, particle size distribution and properties of microcapsules, scanning electron microscopy (SEM), laser particle size analysis and infrared spectroscopy (FTIR) are also applied in the experiments, and the thermal stability of microcapsules is obtained by thermal gravimetric (TG) and differential scanning calorimetry (DSC). The material ratio (core to wall in weight) of microcapsules and stirring rate ratio are discussed. The results show that under the optimum process conditions of a material ratio (core to wall in weight) which is 4:10 and agitating rate of 500r·min‒1, the synthesized polyether silicone microcapsules have a higher yield and the coating and densification properties; their average size is 210μm, and the thermal stability temperature can reach up to 390°C

Research on Preparation and Properties of Coated Polyether Silicone Microencapsulation Based on Polystyrene

By the method of interfacial polymerization, the novel microcapsules were prepared with polystyrene as wall material and polyether silicone as core material. In order to demonstrate the morphologies, particle size distribution and properties of microcapsules, scanning electron microscopy (SEM), laser particle size analysis and infrared spectroscopy (FTIR) are also applied in the experiments, and the thermal stability of microcapsules is obtained by thermal gravimetric (TG) and differential scanning calorimetry (DSC). The material ratio (core to wall in weight) of microcapsules and stirring rate ratio are discussed. The results show that under the optimum process conditions of a material ratio (core to wall in weight) which is 4:10 and agitating rate of 500r·min‒1, the synthesized polyether silicone microcapsules have a higher yield and the coating and densification properties; their average size is 210μm, and the thermal stability temperature can reach up to 390°C

Strong-wind events control barchan dune migration

Abstract Wind is the most important external force in shaping aeolian landforms. Yet, it remains unclear what role the strong-wind events will play in the development of aeolian landforms compared with the effect of regular winds. A fundamental question is, what are the contributions of different wind speed levels to the deformation of aeolian landforms. Here, through in situ measurements of high-sampling-rate wind data and high-resolution topographic data, we analyzed short-term strong-wind events at different levels and monitored the rapid migration of barchan dunes, enabling us to provide a first report on the contribution rate of short-term strong winds to dune migration. Leveraging the linear relationship between sand flux and the migration distance of barchans, we found that the ratio of sand flux generated by short-term strong winds to the total sand flux is equal to the ratio of barchan migration distance caused by strong winds to the total migration distance in the same period. Moreover, a global analysis of three typical barchan fields confirmed the relationship. This study suggests that the development of aeolian landforms is dominantly controlled by the short-term strong-wind events rather than the previously reported time-averaging wind

N-Type Mg3Sb2-xBix Alloys as Promising Thermoelectric Materials

N-type Mg3Sb2-xBix alloys have been extensively studied in recent years due to their significantly enhanced thermoelectric figure of merit (zT), thus promoting them as potential candidates for waste heat recovery and cooling applications. In this review, the effects resulting from alloying Mg3Bi2 with Mg3Sb2, including narrowed bandgap, decreased effective mass, and increased carrier mobility, are summarized. Subsequently, defect-controlled electrical properties in n-type Mg3Sb2-xBix are revealed. On one hand, manipulation of intrinsic and extrinsic defects can achieve optimal carrier concentration. On the other hand, Mg vacancies dominate carrier-scattering mechanisms (ionized impurity scattering and grain boundary scattering). Both aspects are discussed for Mg3Sb2-xBix thermoelectric materials. Finally, we review the present status of, and future outlook for, these materials in power generation and cooling applications

Strong-wind events control barchan dune migration

Wind is the most important external force in shaping aeolian landforms. Yet, it remains unclear what role the strong-wind events will play in the development of aeolian landforms compared with the effect of regular winds. A fundamental question is, what are the contributions of different wind speed levels to the deformation of aeolian landforms. Here, through in situ measurements of high-sampling-rate wind data and high-resolution topographic data, we analyzed short-term strong-wind events at different levels and monitored the rapid migration of barchan dunes, enabling us to provide a first report on the contribution rate of short-term strong winds to dune migration. Leveraging the linear relationship between sand flux and the migration distance of barchans, we found that the ratio of sand flux generated by short-term strong winds to the total sand flux is equal to the ratio of barchan migration distance caused by strong winds to the total migration distance in the same period. Moreover, a global analysis of three typical barchan fields confirmed the relationship. This study suggests that the development of aeolian landforms is dominantly controlled by the short-term strong-wind events rather than the previously reported time-averaging wind. Short-term strong wind events play a crucial role in the evolution and movement of barchan dunes, according to analyses of high-frequency wind sampling data and high-resolution topographic informatio