128 research outputs found
Acute atherosis and oxidative stressin preeclampsia
Preeclampsia is complicating 3.5% of pregnancies in Norway, and is associated with increased mortality and morbidity for both mother and offspring. Deficient placentation with release of substances from the placenta to the maternal circulation is believed to cause hypertension and proteinuria, which are diagnostic of the disease.
The uterine endometrium (decidua) contains blood vessels that are important for placental nutritional transport to the fetus. The walls of these spiral arteries often contain lipid depositions (acute atherosis), causing reduced blood flow to the placenta, hypoxia and oxidative stress.
Gynecologist Nina Kittelsen Harsem demonstrated that a new method for collecting decidual tissue after delivery was better than traditional knife biopsies from the uterine endometrium, as more spiral arteries were collected for demonstration of lipid deposition in morphological investigations. The lipid depositions in the spiral artery walls were more frequent in women with preeclampsia than in women with normal pregnancies, but not all women with preeclampsia demonstrated these vascular changes. In addition, some few women with apparently healthy pregnancies also demonstrated similar evidence of arterial lipid deposition.
Among circulating substances found in increased concentration in preeclampsia are oxidized lipids, including isoprostanes, which could result in a state of increased oxidative stress. In the preeclampsia group there was evidence of augmented oxidative stress in the maternal circulation. In the fetal umbilical cord blood there was not found any difference between preeclampsia and controls.
She then explored whether there is an association between the lipid deposition in the spiral arterial wall and signs of augmented oxidative stress in maternal blood, but no such association were demonstrated.
This study supports the concept that preeclampsia is a heterogeneous disease that does not affect all women, fetuses or placentas similarly
Arctic shelf development as a driver of the progress of the Russian energy system
Today many countries are concerned about the Arctic, including ones which are rather distant from it. High prospectively of the region in the context of undiscovered oil and gas resources is the explanation of this interest. Russia possessing the most significant part of these reserves has a fairly low rate of exploration of the Arctic shelf. Arctic hydrocarbon resources play the important strategic role in the development of the fuel-energy complex of Russia, ensuring its energy security. Therefore, the aim of this study is to identify effective model of development of the offshore fields in the Arctic zone of the Russian Federation. The model of the creation of consortia for the development of the offshore fields is analyzed and it is considered in the context of the Russian Arctic. The conclusion about the efficiency of the application of this model is done
Fetal sex-specific differences in gestational age at delivery in pre-eclampsia : a meta-analysis
Background: Pre-eclampsia (PE) is a major pregnancy disorder complicating up to 8% of pregnancies. Increasing evidence indicates a sex-specific interplay between the mother,placenta and fetus. This may lead to different adaptive mechanisms during pregnancy. Methods: We performed an individual participant data meta-analysis to determine associations of fetal sex and PE, with specific focus on gestational age at delivery in PE. This was done on 219 575 independent live-born singleton pregnancies, with a gestational age at birth between 22.0 and 43.0 weeks of gestation, from 11 studies participating in a worldwide consortium of international research groups focusing on pregnancy. Results: Of the women, 9033 (4.1%) experienced PE in their pregnancy and 48.8% of the fetuses were female versus 51.2% male. No differences in the female/male distribution were observed with respect to term PE (delivered >= 37 weeks). Preterm PE (delivered <37 weeks) was slightly more prevalent among pregnancies with a female fetus than in pregnancies with a male fetus [odds ratio (OR) 1.11, 95% confidence interval (CI) 1.02-1.21]. Very preterm PE (delivered <34 weeks) was even more prevalent among pregnancies with a female fetus as compared with pregnancies with a male fetus (OR 1.36, 95% CI 1.17-1.59). Conclusions: Sexual dimorphic differences in the occurrence of PE exist, with preterm PE being more prevalent among pregnancies with a female fetus as compared with pregnancies with a male fetus and with no differences with respect to term PE.Peer reviewe
Sizing and performance analyses of a combined heating and cooling system with the integration of short- and long-term storages
Technological advancements in the utilization of renewable energy sources have unveiled potentials for increasing building energy efficiency. Integrating heat pump-based energy systems with thermal storages is a suitable option to meet the thermal requirements of modern buildings and exploiting the available renewable energy sources. However, how to size the main components of a heat pump-based energy system with the integration of short- and long-term storages is not yet well explored. Therefore, this study focused on the design and performance analyses of an integrated heating and cooling system consist of a heat pump, borehole long-term thermal storage, and hot water tank short-term thermal. Heat pump models were introduced as parametric models based on the producer data. The dynamic thermal model of the energy system was developed and analysed in MATLAB. Different combinations of heating and cooling loads were tested. Integration of cooling and heating systems was discussed through different operation strategies and challenges were addressed. The results of the parametric analysis identified the key parameters affecting the design of components and efficiency of the system. Moreover, the results showed that lower cooling to heating load ratio leads to an excessive reduction of the ground temperature and overall efficiency over the long-term operation.publishedVersio
Experimental study on the thermal plume from a surgeon in an operating room with mixing ventilation during COVID-19 pandemic
Following the outbreak of COVID-19 (SARS-CoV-2) in 2019, studies show positive results in protecting the surgical staff from patients infected by COVID-19 in operating rooms (ORs) with negative pressure. A negative pressure environment inside the operating room (OR) reduces the virus's circulation outside the OR (Chen et al., 2020). Nevertheless, it is unclear whether the surgeon's thermal plume can impact the transport of contaminants up to the breathing zone and thus cause infection in ORs with various pressure differences compared to adjacent rooms. The results show that a gap between the surgical manikin and the operating table greatly affects the development of the thermal plume from the head surgeon. A plate between the surgical manikin and the operating table may significantly influence the airflow distribution in front of the head surgeon more than the pressure difference inside the operating room.publishedVersio
Cardiac morphology in neonates with fetal growth restriction
Objective: Assess effects of fetal growth restriction (FGR) on cardiac modelling in premature and term neonates.
Study design: Prospective echocardiographic study of a cohort of FGR neonates (n = 21) and controls (n = 41) with normal prenatal growth and circulation.
Results: Unadjusted for gestational age, birth weight, sex, and twin/singleton, Late-FGR neonates had smaller hearts than controls, with globular left ventricles and symmetrical right ventricles. Adjusted estimates showed smaller left ventricles and similarly sized right ventricles, with symmetrical left and right ventricles. Early-FGR (compared with Late-FGR) had smaller hearts and globular left ventricles in unadjusted estimates, but after adjustment, sizes and shapes were similar.
Conclusion: FGR had significant impact on cardiac modelling, seen in both statistical models unadjusted and adjusted for gestational age, birth weight, sex, and twin/singleton. The adjustments, however, refined the results and revealed more specific effects of FGR, thus underscoring the importance of statistical adjustments in such studies.acceptedVersio
Experimental Study on the Surgical Microenvironment in an Operating Room with Mixing Ventilation under Positive and Negative Pressure
Due to the outbreak of Covid-19, negative pressure operating room (NPOR) are strongly recommended to be applied to prevent spreading virus from infected patients to adjacent rooms during surgery procedures. However, there have been few experimental studies on the effect of OR pressure difference on the surgical microenvironment. This study aims to experimentally investigate the airflow distribution in the surgical microenvironment in an OR under different pressure conditions. All measurements were performed in a fullscale laboratory, which has an area of 62 m2, and a mixing ventilation. The air velocity and temperature in the surgical microenvironment of a lying patient were measured under positive pressure of 5 Pa, 10 Pa, 15 Pa and negative pressure of -5 Pa, -10 Pa and -15 Pa. The effect of heat generated by operating lamps was also considered. The results show that the airflow distribution around the surgical wound is dominated by thermal plume from the patient under the condition of both positive and negative pressure. In other areas of the surgical microenvironment, regardless the pressure difference conditions, the room airflow distribution by ventilation system is the dominant factor on surgical microenvironment. Variations in differential pressure can affect the temperature distribution around the surgical site, with a smaller differential pressure producing a slightly larger vertical temperature gradient.publishedVersio
Experimental Study on the Surgical Microenvironment in an Operating Room with Mixing Ventilation under Positive and Negative Pressure
Due to the outbreak of Covid-19, negative pressure operating room (NPOR) are strongly recommended to be applied to prevent spreading virus from infected patients to adjacent rooms during surgery procedures. However, there have been few experimental studies on the effect of OR pressure difference on the surgical microenvironment. This study aims to experimentally investigate the airflow distribution in the surgical microenvironment in an OR under different pressure conditions. All measurements were performed in a fullscale laboratory, which has an area of 62 m2, and a mixing ventilation. The air velocity and temperature in the surgical microenvironment of a lying patient were measured under positive pressure of 5 Pa, 10 Pa, 15 Pa and negative pressure of -5 Pa, -10 Pa and -15 Pa. The effect of heat generated by operating lamps was also considered. The results show that the airflow distribution around the surgical wound is dominated by thermal plume from the patient under the condition of both positive and negative pressure. In other areas of the surgical microenvironment, regardless the pressure difference conditions, the room airflow distribution by ventilation system is the dominant factor on surgical microenvironment. Variations in differential pressure can affect the temperature distribution around the surgical site, with a smaller differential pressure producing a slightly larger vertical temperature gradient.publishedVersio
Experimental study on the thermal plume from a surgeon in an operating room with mixing ventilation during COVID-19 pandemic
Following the outbreak of COVID-19 (SARS-CoV-2) in 2019, studies show positive results in protecting the surgical staff from patients infected by COVID-19 in operating rooms (ORs) with negative pressure. A negative pressure environment inside the operating room (OR) reduces the virus's circulation outside the OR (Chen et al., 2020). Nevertheless, it is unclear whether the surgeon's thermal plume can impact the transport of contaminants up to the breathing zone and thus cause infection in ORs with various pressure differences compared to adjacent rooms. The results show that a gap between the surgical manikin and the operating table greatly affects the development of the thermal plume from the head surgeon. A plate between the surgical manikin and the operating table may significantly influence the airflow distribution in front of the head surgeon more than the pressure difference inside the operating room.publishedVersio
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