Serum albumin levels are inversely related with oxidative stress, but positively related with endothelial function, in pregnant women. However, it is unclear whether hypoalbuminemia in pregnant women ...with preeclampsia (PE) increases the production of oxygen-derived free radicals and impacts endothelial function. The present study aimed to assess the relationship between serum albumin, oxidative stress, and endothelial dysfunction in pregnant women with PE. A total of 75 women with control pregnancy (Control group, n = 30), PE (PE group, n = 24), or gestational hypertension (GH) (GH group, n = 21) were enrolled. We assessed serum albumin levels, diacron-reactive oxygen metabolites (d-ROMs) as an oxygen-derived free radical marker, and flow-mediated dilation (FMD) as a readout for vascular endothelial function during the gestational period and at one month after delivery. During the gestational period, FMD was lower, but d-ROM levels were higher, in the PE and GH groups compared with the Control group. Serum albumin levels were lower in the PE group compared with the Control and GH groups. d-ROM levels were inversely correlated with serum albumin levels (r = -0.54, p < 0.05) and FMD (r = -0.56, p < 0.05) in the PE group, and negatively correlated with FMD, but not serum albumin levels, in the GH group. Serum levels of d-ROMs and albumin, as well as FMD, were similar between groups after delivery. Our findings suggest that reduced serum albumin levels enhance the production of oxygen-derived free radicals, resulting in impaired maternal vascular endothelial function in parturients with PE.
We experienced three cases of intracranial hemorrhage in pregnant women with hypertensive disorders of pregnancy (HDP). Case 1 showed progression of chronic hypertension to superimposed preeclampsia, ...Case 2 was diagnosed with preeclampsia, and Case 3 was diagnosed with gestational hypertension. Intracranial hemorrhage developed at home in Cases 1 and 2, and during cesarean section in Case 3. Cases 1 and 2 were treated by hematoma removal and aneurysm clipping after cesarean section, while Case 3 elected conservative treatment. Case 1 had hypertension from the first trimester but was not diagnosed with chronic hypertension. She later developed severe hypertension but was managed as a normal pregnancy. Case 2, despite having preeclampsia, was not placed under stringent blood pressure control. Case 3, despite persistent high blood pressure during anesthesia, did not receive appropriate blood pressure control with antihypertensives. Appropriate management, including antihypertensive therapy for HDP, may reduce the risk of intracranial hemorrhage.
A 23-year-old woman (gravida 3, para 2) was referred to our hospital at 29 weeks of gestation by a nearby doctor due to hydramnios and suspected umbilical cord hernia. Ultrasound and magnetic ...resonance imaging indicated hydramnios, umbilical cord hernia, and a dilated stomach, with suspicion of upper gastrointestinal atresia. She was hospitalized at 33 weeks of gestation owing to membrane rupture. Fetal bradycardia was observed during delivery, and an emergency cesarean section was performed. A female infant weighing 1,799 g was delivered (Apgar score: 1/1); hemorrhagic ulceration of the umbilical cord was observed. Pancreatic phospholipase A2, trypsin, lipase, and bile acid levels in the amniotic fluid were elevated. The infant died of hemorrhagic shock and circulatory failure on the second day after birth. Based on these findings, we hypothesize that umbilical cord ulceration or hemorrhage may occur in congenital upper gastrointestinal atresia due to discharge of fetal gastrointestinal enzymes into the amniotic fluid.
The authors researched and developed a new measurement method that can continuously measure the contact forces and derailment coefficients at all curves of commercial lines. This new method can ...determine the derailment coefficients, which change according to the friction coefficients and other factors, using the measuring system on in-service trains. In this paper, the analysis results for actual curve data collected on commercial subway lines are introduced. Additionally, parameters that are influential on the changes of the derailment coefficients, such as “friction” and “track irregularity,” are discussed using the regression analysis on the accumulated data with the newly developed system.
•We developed a new measurement method that can continuously measure the contact forces.•The method can grasp rail/wheel interface conditions every time using service trains.•We are collecting huge data on commercial lines by the developed method.•We analyzed the mechanism of increase of L/V (i.e. Y/Q) in sharp curves.•Increases of L/V by friction change and track irregularities are verified.
By using non-contact gap sensors equipped on non-rotating parts of a bogie, a new measuring method of wheel/rail contact forces has been developed. The developed system has been verified to have ...sufficient durability for continuous measurement on in-service trains and sufficient practical accuracy after various stand tests and train running tests. After a long-period of continuous measurement on a commercial subway line, some important characteristics of wheel/rail contact mechanics were found by the analysis of measured data. Numerical simulations of curving with a full vehicle model using multi-body dynamics software were carried out, and according to the comparison with measured data, simulation results agree well with measured data in the steady-state values of derailment coefficients considering friction coefficient.
Possibility of enhancement of saturated pool boiling heat transfer using masking plate under subatmospheric pressure is examined experimentally. Pure water is used as a working fluid, and pressure of ...5kPa is cited. The masking plates used are 5mm thick acrylic plates with φ2mm holes with different pitch (2.5mm,3.0mm and 5.5mm), and they are set with or without spacer of 1mm thickness above the smooth heat transfer surface. Heat transfer performance of masking plate of 3.0mm pitch without spacer is fairly good at the pressure of 5kPa, and heat transfer coefficient of this case is about 1.5 times higher than that of smooth surface at lower heat flux region (less than 200kW/m2).
Possibility of enhancement of boiling heat transfer under subatmospheric pressure is examined experimentally. The range of pressure is between atmospheric pressure to 5kPa. The heat transfer ...coefficient decreases dramatically at the pressure of 5kPa. This tendency is not reliant on types of heat transfer surfaces and working fluids, and differences in heat transfer are almost diminished between those obtained by smooth surface using pure water and by using extended surfaces or surfactant solutions. The experimental heat transfer of smooth surface using pure water is nearly agreed with Labountzov’s correlation. Heat transfer performances of pyramid 2.5mm and copper sintering surfaces are rather good at the pressure of 5kPa, and both performances are almost similar except at atmospheric pressure. Sodium myristate is one of the promising surfactant and shows stable performance under low pressure condition. Heat transfer coefficient of smooth surface using pure water increases linearly with decrease in liquid height. However, reduction in liquid height shows tendency to change to film boiling at an early stage.
Parametric study is conducted for optimizing the thermal performance of loop-thermosiphon for electronic cooling. We have used the Robust design for finding the optimal arrangement of ...loop-thermosiphon. The result shows the influence factors for temperature of heat transfer surface of heat generating device are cooling temperature, filling rate of working fluid and structure of heat transfer surface. On the other hand, those for thermal resistance are filling rate of working fluid, structure of heat transfer surface and type of working fluid. Result obtained by optimized factors show temperature reduction of heat transfer surface by 13.5K and thermal resistance by 38%. Temperature of heat transfer surface decreases with decrease in cooling temperature and filling rate as well as use of high performance heat transfer surface like pyramid 2.5mm of this study. Thermal resistance also decreases with decrease in filling rate and use of high performance heat transfer surface.
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