Low Central Pressure Research Articles

Exotic Stable Branches with Efficient TOV Sequences

Modern inference schemes for the neutron star (NS) equation of state (EoS) require large numbers of stellar models constructed with different EoS, and these stellar models must capture all the behavior of stable stars. I introduce termination conditions for sequences of stellar models for cold nonrotating NSs that can identify all stable stellar configurations up to arbitrarily large central pressures along with an efficient algorithm to build accurate interpolators for macroscopic properties. I explore the behavior of stars with both high- and low-central pressures. Interestingly, I find that EoSs with monotonically increasing sound-speed can produce multiple stable branches (twin stars) and that large phase transitions at high densities can produce stable branches at nearly any mass scale, including sub-solar masses while still supporting stars with M > 2 M ⊙. I conclude with some speculation about the astrophysical implications of this behavior.

Discovery of delayed gas production after implantation of a continuous-flow left ventricular assist device and a preliminary exploration of the mechanisms of its occurrence.

To characterize the gas production phenomenon in the animal model of left ventricular assist device (LVAD), and study its mechanism. An in vitro bubble precipitation experiment was conducted, and the blood samples of Parma spp. animals were divided into ordinary group and oxygen-enriched group according to whether they were oxygenated or not at the time of blood collection, and a static control group was set up respectively. Blood gases were drawn and analyzed before and after the experiment. Activate the pump, and the number of air bubbles in the loop was measured by ultrasound at different rotational speeds; CFD was applied to simulate the flow field in the blood pump, and pressure, fluid velocity vector and shear force diagrams were plotted, and a thrombus model was constructed and the flow field was simulated and plotted as a cloud diagram. There was a statistical difference in the number of bubbles in the inflow and outflow tubes of the blood pump (P values of 0.04 and 0.023, respectively), and the number of bubbles in the outflow tubes of both groups was significantly higher than the number of bubbles in the inflow tubes. The number of bubbles in the tubes of both the oxygen-enriched and normal groups was significantly higher than that in the inflow group. In both the normal and oxygen-enriched groups, more gas was produced at higher speeds than at lower speeds. Blood gas analysis showed that the reduced gas composition in the blood was mainly oxygen. Flow field simulation results: the high rotation speed group had lower central pressure and greater scalar shear. The thrombus simulation group was more prone to turbulence, sudden pressure changes, and greater shear than the normal group. Blood gas production is associated with higher partial pressures of blood oxygen, higher rotation speed, and intrapump thrombosis, and the mechanism of pump gas production is degassing of dissolved gases rather than cavitation of water, and the gas released is most likely to have oxygen. The degassing phenomenon is an warning factor for pump thrombosis.

Witnessing the intracluster medium assembly at the cosmic noon in JKCS 041

ABSTRACT In this work, we study the intracluster medium (ICM) of a galaxy cluster at the cosmic noon: JKCS 041 at z = 1.803. A 28 h long Sunyaev-Zel’dovich (SZ) observation using MUSTANG-2 allows us to detect JKCS 041, even if intrinsically extremely faint compared to other SZ-detected clusters. We found that the SZ peak is offset from the X-ray centre by about 220 kpc in the direction of the brightest cluster galaxy, which we interpret as due to the cluster being observed just after the first passage of a major merger. JKCS 041 has a low central pressure and a low Compton Y compared to local clusters selected by their ICM, likely because the cluster is still in the process of assembly but also in part because of a hard-to-quantify bias in current local ICM-selected samples. JKCS 041 has a 0.5 dex fainter Y signal than another less massive z ∼ 1.8 cluster, exemplifying how much different weak-lensing mass and SZ mass can be at high redshift. The observations we present provide us with the measurement of the most distant resolved pressure profile of a galaxy cluster. Comparison with a library of plausibly descendants shows that JKCS 041 pressure profile will likely increase by about 0.7 dex in the next 10 Gyr at all radii.

Systemic blood pressure in severe aortic stenosis: Haemodynamic correlates and long-term prognostic impact.

Blood pressure (BP) targets in patients with aortic stenosis (AS) are controversial. This study sought to describe the haemodynamic profile and the clinical outcome of severe AS patients with low versus high central meaarterial pressure (MAP). Patients with severe AS (n=477) underwent right and left heart catheterization prior to aortic valve replacement (AVR). The population was divided into MAP quartiles. The mean systolic BP, diastolic BP, and MAP in the entire population were 149±25, 68±11, and 98±14mmHg. Patients in the lowest MAP quartile had the lowest left ventricular ejection fraction (LVEF), systemic vascular resistance, and valvulo-arterial impedance, whereas there were no significant differences in mean right atrial pressure, mean pulmonary artery wedge pressure, pulmonary vascular resistance, and stroke volume index across MAP quartiles. However, left ventricular stroke work index (LVSWI) was lowest in patients in the lowest and highest in those in the highest MAP quartile. After a median (interquartile range) post-AVR follow-up of 3.7 (2.6-5.2) years, mortality was highest in patients in the lowest MAP quartile [hazard ratio 3.08 (95% confidence interval 1.21-7.83); P=0.02 for lowest versus highest quartile]. In the multivariate analysis, lower MAP [hazard ratio 0.78 (95% confidence interval 0.62-0.99) per 10mmHg increase; P=0.04], higher mean right atrial pressure and lower LVEF were independent predictors of death. In severe AS patients, lower MAP reflects lower systemic vascular resistance and valvulo-arterial impedance, which may help to preserve stroke volume and filling pressures despite reduced left ventricular performance, and lower MAP is a predictor of higher long-term post-AVR mortality.

Automated Analysis of Australian Tropical Cyclones with Regression, Clustering and Convolutional Neural Network

Tropical cyclones take precious lives, damage critical infrastructure, and cause economic losses worth billions of dollars in Australia. To reduce the detrimental effect of cyclones, a comprehensive understanding of cyclones using artificial intelligence (AI) is crucial. Although event records on Australian tropical cyclones have been documented over the last 4 decades, deep learning studies on these events have not been reported. This paper presents automated AI-based regression, anomaly detection, and clustering techniques on the largest available cyclone repository covering 28,713 records with almost 80 cyclone-related parameters from 17 January 1907 to 11 May 2022. Experimentation with both linear and logistic regression on this dataset resulted in 33 critical insights on factors influencing the central pressure of cyclones. Moreover, automated clustering determined four different clusters highlighting the conditions for low central pressure. Anomaly detection at 70% sensitivity identified 12 anomalies and explained the root causes of these anomalies. This study also projected parameterization and fine-tuning of AI-algorithms at different sensitivity levels. Most importantly, we mathematically evaluated robustness by supporting an enormous scenario space of 4.737 × 108234. A disaster strategist or researcher can use the deployed system in iOS, Android, or Windows platforms to make evidence-based policy decisions on Australian tropical cyclones.

The Efficacy of the WRF-ARW Model in the Genesis and Intensity Forecast of Tropical Cyclone Fani over the Bay of Bengal

An attempt has been carried out to assess the efficacy of the Weather Research and Forecasting (WRF) model in predicting the genesis and intensification events of Very Severe Cyclonic Storm (VSCS) Fani (26 April – 04 May 2019) over the Bay of Bengal (BoB). WRF model has been conducted on a single domain of 10 km horizontal resolution using the Global Data Assimilation System (GDAS) FNL (final) data (0.250 × 0.250). According to the model simulated outcome analysis, the model is capable of predicting the Minimum Sea Level Pressure (MSLP) and Maximum Sustainable Wind Speed (MSWS) pattern reasonably well, despite some deviations. The model has forecasted the Lowest Central Pressure (LCP) of 919 hPa and the MSWS of 70 ms-1 based on 0000 UTC of 26 April. Except for the model run based on 0000 UTC of 26 April, the simulated values of LCP are relatively higher than the observations. According to the statistical analysis, MSLP and MSWS at 850 hPa level demonstrate a significantly greater influence on Tropical Cyclone (TC) formation and intensification process than any other parameters. The model can predict the intensity features well enough, despite some uncertainty regarding the proper lead time of the model run. Reduced lead time model run, particularly 24 to 48 hr, can be chosen to forecast the genesis and intensification events of TC with minimum uncertainty. Journal of Engineering Science 12(3), 2021, 85-100

Study on Hydrodynamic Characteristics and Environmental Response in Shantou Offshore Area

As a coastal trading city in China, Shantou has complex terrain and changeable sea conditions in its coastal waters. In order to better protect the coastal engineering and social property along the coast, based on the numerical simulation method, this paper constructed a detailed hydrodynamic model of the Shantou sea area, and the measured tide elevation and tidal current were used to verify the accuracy of the model. Based on the simulation results, the tide elevation and current in the study area were analyzed, including the flood and ebb tides of astronomical spring tide, the flood and ebb tides of astronomical neap tide, the high tide, and the low tide. In order to find the main tidal constituent types in this sea, the influence of different tidal constituents on tide elevation and tidal current in the study area was analyzed. At the same time, the storm surge model of the study area was constructed, and the flow field under Typhoon “Mangkhut” in the study area was simulated by using the real recorded data. Typhoon wind fields with different recurrence periods and intensities were constructed to simulate the change in the flow field, the sea water level, and the disaster situation along the coast. The results showed that under normal sea conditions, the sea water flows from southwest to northeast at flood tide and the flow direction is opposite at ebb tide. The tidal range is large in the northwest and small in the southeast of the study area. The tides in the study area are mainly controlled by M2, S2, K1, and O1 tidal constituents, but N2, K2, P1, and Q1 tidal constituents have significant effects on the high water level. The water level caused by typhoons increases significantly along the coast of Shantou City. In the west area of the Rong River estuary, a typhoon with a lower central pressure than 910 hPa may induce a water increase of more than 2 m.

Modeling Study on the Asymmetry of Positive and Negative Storm Surges along the Southeastern Coast of China

In this paper, a three-dimensional storm surge model was developed based on the Finite Volume Community Ocean Model (FVCOM) by the hindcasts of four typhoon-induced storm surges (Chan-hom, Mireille, Herb, and Winnie). After model validation, a series of sensitivity experiments were conducted to explore the effects of key parameters in the wind and pressure field (forward speed, radius of maximum wind (RMW), inflow angle, and central pressure), typhoon path, wind intensity, and topography on the storm surge and surge asymmetry between sea level rise (positive surge) and fall (negative surge) along the southeastern coast of China (SCC). The model results show that lower central pressure and larger RMW could lead to stronger surge asymmetry. A larger inflow angle results in a stronger surge asymmetry. In addition, the path of Chan-hom is the most dangerous path type for the Zhoushan Archipelago area, and that of Winnie follows next. The model results also indicate that the non-linear interaction between wind field and pressure field tends to weaken the peak surge elevation. The effect of topography on storm surges indicates that the peak surge elevation and its occurrence time, as well as the surge asymmetry, increase with a decreasing slope along the SCC.

Low central blood pressure and sympathetic activity predispose for the development of intradialytic hypotension.

Intradialytic hypotension (IDH) may lead to a poor life quality and was associated with cardiovascular mortality in patients under hemodialysis. This study investigated the autonomic nerve and cardiovascular function in the IDH episodes.In this case-control study, 70 end stage renal disease patients (198 visits) were recruited. Pulse wave analysis and heart rate variability were evaluated before hemodialysis. Two definitions of IDH were confirmed by medical records. IDH-f indicated a drop of systolic blood pressure or mean arterial pressure, accompanied with symptoms; IDH-n indicated a low nadir systolic pressure during the hemodialysis. All parameters were evaluated for the possible predisposing factors under each definition.A total of 24 IDH-f and 37 IDH-n were noted in 177 visits. For both definitions, central pulse pressure seemed to be a consistent predisposing factor. Furthermore, lower sympathetic activity (odds ratio [OR] 0.55; 95% confidence interval [CI] 0.35–0.87), lower pulse pressure (OR 0.95; 95% CI 0.92–0.98), and higher augmentation index (OR 17.36; 95% CI 1.48–204.10) were the possible predisposing factors for IDH-f. On the contrary, lower mean arterial pressure (OR 0.87; 95% CI 0.78–0.98) was identified as the possible factor for IDH-n.It was suggested that the lower central pulse pressure and sympathetic activity might be involved in the development of IDH.

A Stochastic Tropical Cyclone Model for the Northwestern Pacific Ocean with Improved Track and Intensity Representations

Tropical cyclones (TCs) present a considerable threat to people and engineering facilities in coastal and offshore regions. Accurate estimation of long-return-period ocean environmental parameters such as wind and waves are limited by sparse historical observations. Thus, stochastic tropical cyclone models (STCMs) are widely used to generate large amounts of artificial synthetic TCs, which can reduce the uncertainty in TC hazard risk assessments. To this end, we developed a new STCM with improved modeling for the TC track and intensity. A linear superposition moving model (LSMM) is proposed for track modeling, in which the translation speeds and directions are expressed as the linear superposition of two parts, representing the temporal development of TCs and the environmental influences, respectively, using a weighting factor. In addition, a three-point intensity model (TPIM) is proposed, in which a third point in addition to the starting and ending points, i.e., the “strongest point” with the lowest central pressure in a TC track, is determined first. Then TC strengthening and decaying is simulated by random sampling. The sensitivity and robustness of this model are analyzed in this study. By comparing with historical data and common models without applying the LSMM and TPIM, it was found that the proposed STCM significantly improves the modeling of TC tracks and the temporal development of TC intensities.

Cosmic rays and magnetic fields in the core and halo of the starburst M82: implications for galactic wind physics

ABSTRACT Cosmic rays (CRs) and magnetic fields may be dynamically important in driving large-scale galactic outflows from rapidly star-forming galaxies. We construct two-dimensional axisymmetric models of the local starburst and superwind galaxy M82 using the CR propagation code galprop. Using prescribed gas density and magnetic field distributions, wind profiles, CR injection rates, and stellar radiation fields, we simultaneously fit both the integrated gamma-ray emission and the spatially resolved multifrequency radio emission extended along M82’s minor axis. We explore the resulting constraints on the gas density, magnetic field strength, CR energy density, and the assumed CR advection profile. In accord with earlier one-zone studies, we generically find low central CR pressures, strong secondary electron/positron production, and an important role for relativistic bremsstrahlung losses in shaping the synchrotron spectrum. We find that the relatively low central CR density produces CR pressure gradients that are weak compared to gravity, strongly limiting the role of CRs in driving M82’s fast and mass-loaded galactic outflow. Our models require strong magnetic fields and advection speeds of the order of ∼1000 km s−1 on kpc scales along the minor axis in order to reproduce the extended radio emission. Degeneracies between the controlling physical parameters of the model and caveats to these findings are discussed.

High-Impact Extratropical Cyclones along the Northeast Coast of the United States in a Long Coupled Climate Model Simulation

Abstract High-impact extratropical cyclones (ETCs) cause considerable damage along the northeast coast of the United States through strong winds and inundation, but these relatively rare events are difficult to analyze owing to limited historical records. Using a 1505-yr simulation from the GFDL FLOR coupled model, statistical analyses of extreme events are performed including exceedance probability computations to compare estimates from shorter segments to estimates that could be obtained from a record of considerable length. The most extreme events possess characteristics including exceptionally low central pressure, hurricane-force winds, and a large surge potential, which would greatly impact nearby regions. Return level estimates of metrics of ETC intensity using shorter, historical-length segments of the FLOR simulation are underestimated compared to levels determined using the full simulation. This indicates that if the underlying distributions of observed ETC metrics are similar to those of the 1505-yr FLOR distributions, the actual frequency of extreme ETC events could also be underestimated. Comparisons between FLOR and reanalysis products suggest that not all features of simulated high-impact ETCs are representative of observations. Spatial track densities are similar, but FLOR exhibits a negative bias in central pressure and a positive bias in wind speed, particularly for more intense events. Although the existence of these model biases precludes the quantitative use of model-derived return statistics as a substitute for those derived from shorter observational records, this work suggests that statistics from future models of higher fidelity could be used to better constrain the probability of extreme ETC events and their impacts.

Red blood cell transfusion in liver resection.

Several modalities exist for the management of hepatic neoplasms. Resection, the most effective approach, carries significant risk of hemorrhage. Blood loss may be corrected with red blood cell transfusion (RBCT) in the short term, but may ultimately contribute to negative outcomes. Using available literature, we seek to define the frequency and risk factors of blood loss and transfusion following hepatectomy. The impact of blood loss and RBCT on short- and long-term outcomes is explored with an emphasis on peri-operative methods to reduce hemorrhage and transfusion. Following hepatic surgery, 25.2-56.8% of patients receive RBCT. Patients who receive RBCT are at increased risk of surgical morbidity in a dose-dependent manner. The relationship between blood transfusion and surgical mortality is less apparent. RBCT might also impact long-term oncologic outcomes including disease recurrence and overall survival. Risk factors for bleeding and blood transfusion include hemoglobin concentration < 12.5g/dL, thrombocytopenia, pre-operative biliary drainage, presence of background liver disease (such as cirrhosis), coronary artery disease, male gender, tumor characteristics (type, size, location, presence of vascular involvement), extent of hepatectomy, concomitant extrahepatic organ resection, and operative time. Strategies to mitigate blood loss or transfusion include pre-operative (iron, erythropoietin), intra-operative (vascular occlusion, parenchymal transection techniques, hemostatic agents, antifibrinolytics, low central pressure, hemodilution, autologous blood recycling), and post-operative (normothermia, correction of coagulopathy, optimization of nutrition, restrictive transfusion strategy) methods. Blood loss during hepatectomy is common and several risk factors can be identified pre-operatively. Blood loss and RBCT during hepatectomy is associated with post-operative morbidity and mortality. Disease-free recurrence, disease-specific survival, and overall survival may be associated with blood loss and RBCT during hepatectomy. Attention to pre-operative, intra-operative, and post-operative strategies to reduce blood loss and RBCT is necessary.

Changes in Hurricanes from a 13-Yr Convection-Permitting Pseudo–Global Warming Simulation

Abstract Tropical cyclones have enormous costs to society through both loss of life and damage to infrastructure. There is good reason to believe that such storms will change in the future as a result of changes in the global climate system and that such changes may have important socioeconomic implications. Here a high-resolution regional climate modeling experiment is presented using the Weather Research and Forecasting (WRF) Model to investigate possible changes in tropical cyclones. These simulations were performed for the period 2001–13 using the ERA-Interim product for the boundary conditions, thus enabling a direct comparison between modeled and observed cyclone characteristics. The WRF simulation reproduced 30 of the 32 named storms that entered the model domain during this period. The model simulates the tropical cyclone tracks, storm radii, and translation speeds well, but the maximum wind speeds simulated were less than observed and the minimum central pressures were too large. This experiment is then repeated after imposing a future climate signal by adding changes in temperature, humidity, pressure, and wind speeds derived from phase 5 of the Coupled Model Intercomparison Project (CMIP5). In the current climate, 22 tracks were well simulated with little changes in future track locations. These simulations produced tropical cyclones with faster maximum winds, slower storm translation speeds, lower central pressures, and higher precipitation rates. Importantly, while these signals were statistically significant averaged across all 22 storms studied, changes varied substantially between individual storms. This illustrates the importance of using a large ensemble of storms to understand mean changes.

Medicanes as subtropical cyclones: the December 2005 case from the perspective of surface pressure tendency diagnostics and atmospheric water budget

Mediterranean cyclones with tropical‐like characteristics such as spiral cloud coverage and a central cloud‐free “eye” are referred to as medicanes. These systems have been analyzed due to their relation with high‐impact weather. In previous studies, the identification of medicanes has been typically performed subjectively, using satellite pictures, but also objectively through three‐dimensional diagnosis of a warm core and an axisymmetric structure. Despite the presence of these characteristics, it is still unclear if medicanes show dynamical similarities with tropical cyclones.We analyse the (thermo‐)dynamics of a recognized medicane that occurred in December 2005 by applying different diagnostics to a high‐resolution simulation. These diagnostics are focused on the intensification, dynamical structure and water budget of this representative case, aiming to highlight extratropical and tropical cyclone characteristics.Three stages in the medicane life cycle are identified. In stage I, a potential vorticity (PV) streamer reaches the Mediterranean, triggering deep convection and deepening the medicane's central surface pressure due to diabatic heating. When the lowest central pressure is reached (stage II), the medicane presents a warm core and an axisymmetric structure. However, convection is rather weak and the PV streamer evolves into a cut‐off system which contributes to the deepening of the medicane's surface pressure. Finally, stage III corresponds to the decay phase where the medicane tends to weaken and lose its axisymmetric structure.Our results highlight the detrimental role of deep convection prior to the mature stage of the medicane, as well as the possibility of positive or negative feedback of upper‐tropospheric dynamics on the central surface pressure. In addition, we show that the medicane warm core might be achieved due to front seclusion, while the “eye” formation is associated with dry air intrusions. Our analysis suggests that medicanes are hybrid systems combining characteristics of both tropical and extratropical cyclones and thus they plausibly correspond to subtropical cyclones.

Impacts of SST Patterns on Rapid Intensification of Typhoon Megi (2010)

AbstractTyphoon Megi (2010), a very intense tropical cyclone with a minimum central pressure of 885 hPa, was characterized by especially rapid intensification. We investigated this intensification process by a simulation experiment using a high‐resolution (0.02° × 0.02°) three‐dimensional atmosphere‐ocean coupled regional model. We also performed a sensitivity experiment with a time‐fixed sea surface temperature (SST). The coupled model successfully simulated the minimum central pressure of Typhoon Megi, whereas the fixed SST experiment simulated an excessively low minimum central pressure of 839 hPa. The simulation results also showed a close relationship between the radial SST profiles and the rapid intensification process. Because the warm sea increased near‐surface water vapor and hence the convective available potential energy, the high SST in the eye region facilitated tall and intense updrafts inside the radius of maximum wind speed and led to the start of rapid intensification. In contrast, high SST outside this radius induced local secondary updrafts that inhibited rapid intensification even if the mean SST in the core region exceeded 29.0°C. These secondary updrafts moved inward and eventually merged with the primary eyewall updrafts. Then the storm intensified rapidly when the high SST appeared in the eye region. Thus, the changes in the local SST pattern around the storm center strongly affected the rapid intensification process by modulating the radial structure of core convection. Our results also show that the use of a high‐resolution three‐dimensional atmosphere‐ocean coupled model offers promise for improving intensity forecasts of tropical cyclones.

Solar Influence on Tropical Cyclone in Western North Pacific Ocean

Solar activity is known to be linked to changes in the Earth’s weather and climate. Nonetheless, for other types of extreme weather, such as tropical cyclones (TCs), the available evidence is less conclusive. In this study the modulation of TC genesis over the western North Pacific by the solar activity is investigated, in comparison with a large-scale environmental parameter, i.e., El-Niño-Southern Oscillation (ENSO). For this purpose, we have obtained the best track data for TCs in the western North Pacific from 1977 to 2016, spanning from the solar cycle 21 to the solar cycle 24. We have confirmed that in the El-Niño periods TCs tend to form in the southeast, reach its maximum strength in the southeast, and end its life as TSs in the northeast, compared with the La-Niña periods. TCs occurring in the El-Niño periods are found to last longer compared with the La-Niña periods. Furthermore, TCs occurring in the El-Niño periods have a lower central pressure at their maximum strength than those occurring in the La-Niña periods. We have found that TCs occurring in the solar maximum periods resemble those in the El-Niño periods in their properties. We have also found that TCs occurring in the solar descending periods somehow resemble those in the El-Niño periods in their properties. To make sure that it is not due to the ENSO effect, we have excluded TCs both in the El-Niño periods and in the La-Niña periods from the data set and repeated the analysis. In addition to this test, we have also reiterated our analysis twice with TCs whose maximum sustained winds speed exceeds 17 m/s, instead of 33 m/s, as well as TCs designated as a typhoon, which ends up with the same conclusions.

Efficacy of stroke volume variation combined with low central venous pressure-directed fluid therapy in patients undergoing liver cancer resection

Objective To evaluate the efficacy of stroke volume variation(SVV)combined with controlled low central venous pressure(CLCVP)-directed fluid therapy in the patients undergoing liver cancer resection. Methods Seventy American Society of Anesthesiologists physical status Ⅰ or Ⅱ patients, aged 40-60 yr, with body mass index of 20-25 kg/m2, scheduled for elective liver cancer resection under general anesthesia, were divided into 2 groups(n=35 each) using a random number table: routine fluid replacement group(R group) and SVV combined with CLCVP-guided fluid replacement group(SC group). In R group, routine fluid replacement included compensatory volume expansion, physiological requirement, cumulative loss, continued loss (intraoperative blood loss) and 3rd space losses, maintaining mean arterial pressure>70 mmHg, central venous pressure<4 cmH2O and heart rate <100 bpm.Central venous pressure was maintained <4 cmH2O and SVV <12% during operation in SC group.The operation time, total amount of crystalloid and colloid solution infused, urine volume and development of intraoperative hypotension and bradycardia were recorded.Blood samples from the left radial artery and central vein were collected before anesthesia induction and at the end of operation for measurement of the blood lactate concentration, and the oxygen supply index, oxygen consumption index and oxygen uptake rate were calculated.Blood samples from the ulnar vein were collected before anesthesia induction and at the end of operation for determination of serum β2-microglobulin concentrations.The development of intraoperative adverse cardiovascular events was recorded, and the occurrence of postoperative complications was observed. Results Compared with R group, the total amount of crystalloid solution infused was significantly decreased, the total amount of colloid solution infused and urine volume were increased, the incidence of intraoperative hypotension and bradycardia was decreased, oxygen supply index, oxygen consumption index and oxygen uptake rate were increased at the end of operation, and the lactate concentration in arterial blood, serum β2-microglobulin concentration and rate of postoperative pulmonary infection were decreased in SC group (P<0.05). Conclusion SVV combined with CLCVP-directed fluid therapy produces better efficacy than routine fluid replacement in the patients undergoing liver resection. Key words: Stroke volume; Central venous pressure; Liver neoplasms

The effect of combined therapy on the properties of the vessel wall in patients at high risk of cardiovascular complications

Introduction. The evaluation of therapy effectiveness in patients at high risk of cardiovascular complications includes the evaluation of target organs condition. A complex approach means follow-up control of laboratory and instrumental data. Materials and methods. The study included 113 patients with hypertension and nonstenotic atherosclerosis of brachiocephalic arteries. All the patients received antihypertensive therapy and some received hypolipidemic drugs. Cholesterol and low density lipoproteins (LDL) levels, brachial and central blood pressure (BP), brachial-ankle and carotid-femoral pulse wave velocity (baPWV and cfPWV, respectively), augmentation index (AI) of fibrosis markers (C-terminal telopeptide from collagen I (CITP) and C-terminal terminal propeptide of pro-collagen I (PINP) were assessed at baseline, after 6 months and 12 months of treatment with fixed combination of amlodipine, lisinopril and rosuvastatin. Results. The conducted therapy was followed by lowering the LDL levels from 3.9 (3.1; 4.6) to 2 (1.8; 2.3) mmol/L (p

Paleomagnetic evidence for dynamo activity driven by inward crystallisation of a metallic asteroid

The direction in which a planetary core solidifies has fundamental implications for the feasibility and nature of dynamo generation. Although Earth's core is outwardly solidifying, the cores of certain smaller planetary bodies have been proposed to inwardly solidify due to their lower central pressures. However, there have been no unambiguous observations of inwardly solidified cores or the relationship between this solidification regime and planetary magnetic activity. To address this gap, we present the results of complimentary paleomagnetic techniques applied to the matrix metal and silicate inclusions within the IVA iron meteorites. This family of meteorites has been suggested to originate from a planetary core that had its overlaying silicate mantle removed by collisions during the early solar system. This process is thought to have produced a molten ball of metal that cooled rapidly and has been proposed to have inwardly solidified. Recent thermal evolution models of such a body predict that it should have generated an intense, multipolar and time-varying dynamo field. This field could have been recorded as a remanent magnetisation in the outer, cool layers of a solid crust on the IVA parent core. We find that the different components in the IVA iron meteorites display a range of paleomagnetic fidelities, depending crucially on the cooling rate of the meteorite. In particular, silicate inclusions in the quickly cooled São João Nepomuceno meteorite are poor paleomagnetic recorders. On the other hand, the matrix metal and some silicate subsamples from the relatively slowly cooled Steinbach meteorite are far better paleomagnetic recorders and provide evidence of an intense (≳100 μT) and directionally varying (exhibiting significant changes on a timescale ≲200 kyr) magnetic field. This is the first demonstration that some iron meteorites record ancient planetary magnetic fields. Furthermore, the observed field intensity, temporal variability and dynamo lifetime are consistent with thermal evolution models of the IVA parent core. Because the acquisition of remanent magnetisation by some IVA iron meteorites require that they cooled below their Curie temperature during the period of dynamo activity, the magnetisation carried by Steinbach also provides strong evidence favouring the inward solidification of its parent core.