Experimental Validation for the Theory of Blisters’ Instabilities

Blister formation is a universal problem that can be witnessed within a wide range of contents. It is first documented as a side effect of syringomyelia and other diseases. Later on, the forming of blisters are also observed during the cell apoptosis, which leads to the hypothesis that it could have some intricate relationships with the death of living organisms. Other than biological problems, blister forming is also a common phenomenon in thin film technologies. Therefore, the research in the forming of blisters is essential and critical in both engineering and science fields. In this thesis, we study the problem of a growing blister made of a rubber-like membrane adhered on a rigid substrate, and the implications that it might have on possible artificial shape-morphing skins. We show that a blister test is a problem driven by competition between two instabilities: one inherent to the rubber, and second one pertaining to the adhesion with the substrate. This enables obtaining different results with such that the final blister profile can be perfectly controlled by only adjusting the thickness of the film and the inflation rate. Given the theory, the rest part of this thesis is mainly focused on the experimental validation of it. We designed our unique experimental systems to analyze such problem and by matching the experimental results and simulation results, we can verify the validity of our theory

PARK16 rs708730 Polymorphism Decreases Parkinson’s Disease Risk in European Ancestry Population: A Meta-analysis

Parkinson’s disease (PD) is a complex fatal chronic neurodegenerative disease most common in elderly people. The early genome-wide association studies (GWAS) found that the minor allele variant of PARK16 rs708730 polymorphism is a significant protective factor for PD in Caucasian populations. However, these results cannot be repeated by the following studies in Caucasian populations and other populations. We considered that the inconsistency of the findings may be caused by the small-scale samples or the heterogeneity among different populations. Therefore, in this study, we synthesized the previous related GWAS studies through three authoritative sources, and used the large-scale samples (10,645 PD cases and 30,499 controls) to reevaluate the association between rs708730 polymorphism and PD. The results showed that there is no association between them in Asian ancestry population. While, in European ancestry population, we found that the minor allele variant (G) of rs708730 polymorphism is significantly associated with a decreased risk of PD. Collectively, our findings further verified the association of rs708730 with PD and show its genetic heterogeneity among different populations, which can help to develop a better understanding of the PD’s pathogenesis

A Large-Range and High-Sensitivity Fiber-Optic Fabry–Perot Pressure Sensor Based on a Membrane-Hole-Base Structure

In the field of in situ measurement of high-temperature pressure, fiber-optic Fabry–Perot pressure sensors have been extensively studied and applied in recent years thanks to their compact size and excellent anti-interference and anti-shock capabilities. However, such sensors have high technological difficulty, limited pressure measurement range, and low sensitivity. This paper proposes a fiber-optic Fabry–Perot pressure sensor based on a membrane-hole-base structure. The sensitive core was fabricated by laser cutting technology and direct bonding technology of three-layer sapphire and develops a supporting large-cavity-length demodulation algorithm for the sensor’s Fabry–Perot cavity. The sensor exhibits enhanced sensitivity, a simplified structure, convenient preparation procedures, as well as improved pressure resistance and anti-harsh environment capabilities, and has large-range pressure sensing capability of 0–10 MPa in the temperature range of 20–370 °C. The sensor sensitivity is 918.9 nm/MPa, the temperature coefficient is 0.0695 nm/(MPa∙°C), and the error over the full temperature range is better than 2.312%

Double F-P interference optical fiber Temperature and gas pressure sensor based on hollow core Bragg fiber.

A dual Fabry-Perot interferometric (FPI) temperature-gas pressure dual parametric sensor based on a hollow core Bragg fiber (HCBF) is introduced and validated experimentally for gas pressure monitoring in high-temperature settings. This dual parametric sensor employs a single mode fiber-hollow core Bragg fiber-single mode fiber (SMF-HCBF-SMF) structure to form a dual FPI, while the gas flow channel of the HCBF were processed by Femtosecond laser to make the sensor sensitive to gas pressure. Additionally, a novel white light interference demodulation technique is developed to demodulate the dual parametric sensor. Experimental findings corroborate theoretical predictions, the pressure measurement range of the proposed sensor reaches 0~10 MPa, the temperature measurement reaches 600°C. Pressure sensitivity greater than 50 nm/MPa over the full temperature rang. The high temperature and high sensitivity resistance of the proposed sensor highlights its potential for monitoring gas pressure in extreme high temperature environments

Risk Factors and Pregnancy Outcome in Women with a History of Cesarean Section Complicated by Placenta Accreta

Abstract. Objective:. To explore the risk factors and pregnancy outcomes in women with a history of cesarean section complicated by placenta accreta (PA). Methods:. This case-control study included clinical data from singleton mothers with a history of cesarean section in 11 public tertiary hospitals in seven provinces of China between January 2017 and December 2017. According to the intraoperative findings after delivery, the study population was divided into PA and non-PA groups. We compared the pregnancy outcomes between the two groups, used multivariate logistic regression to analyze the risk factors for placental accreta. Results:. For this study we included 11,074 pregnant women with a history of cesarean section; and of these, 869 cases were in the PA group and 10,205 cases were in the non-PA group. Compared with the non-PA group, the probability of postpartum hemorrhage (236/10,205, 2.31% vs. 283/869, 32.57%), severe postpartum hemorrhage (89/10,205, 0.87% vs. 186/869, 21.75%), diffuse intravascular coagulation (3/10,205, 0.03% vs. 4/869, 0.46%), puerperal infection (33/10,205, 0.32% vs. 12/869, 1.38%), intraoperative bladder injury (1/10,205, 0.01% vs. 16/869, 1.84%), hysterectomy (130/10,205, 1.27% vs. 59/869, 6.79%), and blood transfusion (328/10,205,3.21% vs. 231/869,26.58%) was significantly increased in the PA group (P < 0.05). At the same time, the neonatal birth weight (3250.00 (2950.00–3520.00) g vs. 2920.00 (2530.00–3250.00) g), the probability of neonatal comorbidities (245/10,205, 2.40% vs. 61/869, 7.02%), and the rate of neonatal intensive care unit admission (817/10,205, 8.01% vs. 210/869, 24.17%) also increased significantly (P < 0.05). Weight (odds ratio (OR) = 1.03, 95% confidence interval (CI): 1.01–1.05)), parity (OR = 1.18, 95%CI: 1.03–1.34), number of miscarriages (OR = 1.31, 95%CI: 1.17–1.47), number of previous cesarean sections (OR = 2.57, 95%CI: 2.02–3.26), history of premature rupture of membrane (OR = 1.61, 95%CI: 1.32–1.96), previous cesarean-section transverse incisions (OR = 1.38, 95%CI: 1.12–1.69), history of placenta previa (OR = 2.44,95%CI: 1.50–3.96), and the combination of prenatal hemorrhage (OR = 9.95,95%CI: 8.42–11.75) and placenta previa (OR = 91.74, 95%CI: 74.11–113.56) were all independent risk factors for PA. Conclusion:. There was an increased risk of adverse outcomes in pregnancies complicated by PA in women with a history of cesarean section, and this required close clinical attention. Weight before pregnancy, parity, number of miscarriages, number of previous cesarean sections, history of premature rupture of membranes, past transverse incisions in cesarean sections, a history of placenta previa, prenatal hemorrhage, and placenta previa were independent risk factors for pregnancies complicated with PA in women with a history of cesarean section. These independent risk factors showed a high value in predicting the risk for placentab accreta in pregnancies of women with a history of cesarean section