Circulation Pathways Research Articles

Open ocean convection drives enhanced eastern pathway of the Glacial Atlantic Meridional Overturning Circulation

Abundant proxy records suggest a profound reorganization of the Atlantic Meridional Overturning Circulation (AMOC) during the Last Glacial Maximum (LGM, ~21,000 y ago), with the North Atlantic Deep Water (NADW) shoaling significantly relative to the present-day (PD) and forming Glacial North Atlantic Intermediate Water (GNAIW). However, almost all previous observational and modeling studies have focused on the zonal mean two-dimensional AMOC feature, while recent progress in the understanding of modern AMOC reveals a more complicated three-dimensional structure, with NADW penetrating from the subpolar North Atlantic to lower latitude through different pathways. Here, combining 231Pa/230Th reconstructions and model simulations, we uncover a significant change in the three-dimensional structure of the glacial AMOC. Specifically, the mid-latitude eastern pathway (EP), located east of the Mid-Atlantic Ridge and transporting about half of the PD NADW from the subpolar gyre to the subtropical gyre, experienced substantial intensification during the LGM. A greater portion of the GNAIW was transported in the eastern basin during the LGM compared to NADW at the PD, resulting in opposite 231Pa/230Th changes between eastern and western basins during the LGM. Furthermore, in contrast to the wind-steering mechanism of EP at PD, the intensified LGM EP was caused primarily by the rim current forced by the basin-scale open-ocean convection over the subpolar North Atlantic. Our results underscore the importance of accounting for three-dimensional oceanographic changes to achieve more accurate reconstructions of past AMOC.

Multiscale X-ray phase-contrast CT uncovers adaptive changes and compensatory mechanisms of circulatory pathways during acute liver injury

Intrahepatic circulation is essential for the repair of acute liver injury (ALI); however, very limited information is available concerning changes in the circulatory pathways during ALI. Therefore, multi-scale X-ray phase-contrast CT combined with three-dimensional (3D) visualization is used to quantitatively analyze the intrahepatic circulation pathway (including the hepatic vein, portal vein and hepatic sinusoid) in the mouse model via the intraperitoneal injection of carbon tetrachloride (CCl4) from acute injury to recovery. The results demonstrate that the liver still preserves some vessel-like channels accessed to the central vein when the injury causes the severe collapse of the hepatic sinusoids that cannot be observed in two-dimensional pathologic slices. Moreover, angiogenesis is observed in the terminal branches of the hepatic vein and portal vein. Additionally, we extend the two-dimensional primary lobule to a 3D model and find that the sinusoids in zone III have the most severe injury. The sinusoids in different zones also show changes in parameters such as density and mean diameter during the ALI. In conclusion, phase-contrast CT can reveal the intact vascular system within the liver lobes, thus providing critical information for studying the mechanisms involved in the evolution of circulatory structures from damage to repair.

Abyssal Slope Currents

Abstract Realistic computational simulations in different oceanic basins reveal prevalent prograde mean flows (in the direction of topographic Rossby wave propagation along isobaths; a.k.a. topostrophy) on topographic slopes in the deep ocean, consistent with the barotropic theory of eddy-driven mean flows. Attention is focused on the Western Mediterranean Sea with strong currents and steep topography. These prograde mean currents induce an opposing bottom drag stress and thus a turbulent boundary-layer mean flow in the downhill direction, evidenced by a near-bottom negative mean vertical velocity. The slope-normal profile of diapycnal buoyancy mixing results in down-slope mean advection near the bottom (a tendency to locally increase the mean buoyancy) and up-slope buoyancy mixing (a tendency to decrease buoyancy) with associated buoyancy fluxes across the mean isopycnal surfaces (diapycnal downwelling). In the upper part of the boundary layer and nearby interior, the diapycnal turbulent buoyancy flux divergence reverses sign (diapycnal upwelling), with upward Eulerian mean buoyancy advection across isopycnal surfaces. These near-slope tendencies abate with further distance from the boundary. An along-isobath mean momentum balance shows an advective acceleration and a bottom-drag retardation of the prograde flow. The eddy buoyancy advection is significant near the slope, and the associated eddy potential energy conversion is negative, consistent with mean vertical shear flow generation for the eddies. This cross-isobath flow structure differs from previous proposals, and a new one-dimensional model is constructed for a topostrophic, stratified, slope bottom boundary layer. The broader issue of the return pathways of the global thermohaline circulation remains open, but the abyssal slope region is likely to play a dominant role.

Phylo-geo haplotype network-based characterization of SARS-CoV-2 strains circulating in India (2020-2022).

Background & objectives Genetic analysis of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) strains circulating in India during 2020-2022 was carried out to understand the evolution of potentially expanding and divergent clades. Methods SARS-CoV-2 sequences (n=612) randomly selected from among the sequences of samples collected through a nationwide network of Virus Research Diagnostic Laboratories during 2020 (n=1532) and Indian sequences available in Global Initiative on Sharing All Influenza Data during March 2020-March 2022 (n=53077), were analyzed using the phylo-geo haplotype network approach with reference to the Wuhan prototype sequence. Results On haplotype analysis, 420 haplotypes were revealed from 643 segregating sites among the sequences. Haplotype sharing was noted among the strains from different geographical regions. Nevertheless, the genetic distance among the viral haplotypes from different clades could differentiate the strains into distinct haplo groups regarding variant emergence. Interpretation & conclusions The haplotype analysis revealed that the G and GR clades were co-evolved and an epicentrefor the evolution of the GH, GK and GRA clades. GH was more frequently identified in northern parts of India than in other parts, whereas GK was detected less in north India than in other parts. Thus, the network analysis facilitated a detailed illustration of the pathways of evolution and circulation of SARS-CoV-2 variants.

Study on the application of a segmented sodium citrate solution anticoagulation strategy in critically ill patients receiving CRRT: a prospective, randomized controlled study

BackgroundTo explore the feasibility and effectiveness of a segmented sodium citrate solution anticoagulation strategy in patients receiving CRRT.MethodsA prospective, randomized controlled study was conducted.ResultsAccording to the inclusion and exclusion criteria, 80 patients were included and randomly divided into two groups. Moreover, coagulation indices, liver function indices, renal function indices, and SOFA and APACHE II scores did not significantly differ between the two groups (P > 0.05). The coagulation grade of the venous ports in the experimental group was lower than that in the control group and the two groups of filters, but the difference was not statistically significant (P = 0.337). Both sodium citrate solution infusion methods maintained a low blood calcium concentration (0.25–0.45 mmol/L) in the peripheral circulation pathway, and no patient developed hypocalcaemia (< 1.0 mmol/L). The lifespans of the extracorporeal circulation tube in the experimental group and the control group were 69.43 ± 1.49 h and 49.39 ± 2.44 h, respectively (t = 13.316, P = 0.001).ConclusionThe segmented citrate solution anticoagulation strategy could extend the lifespan of the extracorporeal circulation tube and improve CRRT efficacy.Trial registrationThe Chinese Clinical Trial Registry number is ChiCTR2200057272. Registered on March 5, 2022.

The coupling of winds, ocean turbulence, and High Salinity Shelf Water in the Terra Nova Bay Polynya

The Terra Nova Bay (TNB) Polynya in the Western Ross Sea of Antarctica is a major producer of High Salinity Shelf Water (HSSW), a precursor to Antarctica Bottom Water (AABW). Processes occurring in and around the polynya can therefore effect change in the lower limb of overturning circulation in this region. Here, we use data from a densely-instrumented upper-ocean mooring, deployed for 1 year in a region of active HSSW formation within TNB, to examine the coupling of surface brine rejection and vertical mixing to katabatic wind forcing. We find a high correlation between salinity and winds during the wintertime HSSW production season at the mooring site, with a lag-response of 20 h in near-surface (∼47 m) salinity to winds measured at the nearby Automatic Weather Station (AWS) Manuela. Salinity and temperature measurements show a fully destratified water column by June, with a lag-response of near-seabed (∼360 m) salinity to near-surface salinity of just 5 h. Measurements of turbulent kinetic energy (TKE) dissipation rate (ɛ) from moored pulse-coherent acoustic Doppler current profilers (ADCPs) show general agreement with classic boundary layer scaling (BLS), and calculations of a vertical mixing timescale using the Obukhov length scale average to ∼2.5 h during austral winter, consistent with the 5-h lag time observed in the salinity data. Comparisons to data from concurrent mooring deployments along the southern boundary of TNB, as well as to previously published assessments of model simulations and data from Climatic Long-term Interaction for the Mass-balance in Antarctica (CLIMA) moorings, allow us to explore spatial variability in the coupling of winds and salinity across TNB and to speculate on possible HSSW circulation pathways.

Circulation and Hydrography in the Northwestern Barents Sea: Insights From Recent Observations and Historical Data (1950–2022)

AbstractThe Barents Sea is one of the main pathways for warm and saline Atlantic Water (AW) entering the Arctic Ocean. It is an important region where water mass transformation and dense‐water production contribute to the Atlantic meridional overturning circulation. Here, we present data from three cruises and nine glider missions conducted between 2019 and 2022 in the northwestern Barents Sea, and compare them with historical data collected between 1950 and 2009. We present circulation pathways, hydrography and volume transports of Atlantic‐ and Arctic‐origin waters. Our observations show that 0.9 ± 0.1 Sv (1 Sv = 106 m3 s−1) of Atlantic‐origin water reaches the Polar Front (PF) region before splitting into several branches and eventually subducting beneath Polar Water (PW). The amount of Atlantic‐origin water stored in the Olga Basin north of the PF is controlled by the density difference between AW and PW, and reached a maximum in the 90s when PW was particularly fresh. In the recent period from 2019 to 2022, the inflow of AW into the Barents Sea freshened by up to 0.1 g kg−1 compared to previous decades. This led to a reduction in the production of dense water, an increased temperature gradient across the PF, and a reduced poleward transport of warm water.

Kritik Arsitektur terhadap Aspek Inklusif Aksesibilitas Hubungan Horizontal Antar Ruang atau Antar Bangunan Studi Kasus: Selasar RSP (Rumah Sakit Paru) Dr. H. A. Rotinsulu Bandung

Hallway of the Lung Hospital DR. H. A. Rotinsulu is one of the facilities that functions as the accessibility of relationships between spaces or between buildings. Tues as referred to in the Lung Hospital DR. H. A. Rotinsulu is a means of connecting circulation pathways between rooms or between buildings outside a building that is not limited by walls or limited by at most 1 (one) side wall. The object of Architectural Criticism is the hall of Dr. Lung Hospital. H.A Rotinsulu Bandung. Architectural criticism is carried out in the form of observations and measurements in the field on several walkway segments, based on the steepness of the contours that have been measured influenced by the long span of each walkway segment, which has been divided into observations according to the existing conditions of the walkways of Dr. Lung Hospital. H. A Rotinsulu Bandung, then a study was carried out in the form of an evaluation of the existing conditions of the walkway according to Ministerial Regulation PUPR No. 14 of 2017 concerning Requirements for Building Facilities and Law no. 8 of 2016 concerning Persons with Disabilities. The aspects studied are: 1. Needs for space for movement of users, 2. Circulation, 3. Guiding paths 4. Placement of gathering points, 5. Waiting area or right of way in transit to the hall rest. The basic dimensions of space and related facilities according to the object of observation refer to the Universal Design principle or the principle of inclusive design so that each user can move easily, safely, comfortably and independently.

The role of lactate-induced protein lactylation in gliomas: implications for preclinical research and the development of new treatments.

The most prevalent primary brain tumors in adults are gliomas. In addition to insufficient therapeutic alternatives, gliomas are fatal mostly due to the rapid proliferation and continuous infiltration of tumor cells into the surrounding healthy brain tissue. According to a growing body of research, aerobic glycolysis, or the Warburg effect, promotes glioma development because gliomas are heterogeneous cancers that undergo metabolic reprogramming. Therefore, addressing the Warburg effect might be a useful therapeutic strategy for treating cancer. Lactate plays a critical role in reprogramming energy metabolism, allowing cells to rapidly access large amounts of energy. Lactate, a byproduct of glycolysis, is therefore present in rapidly proliferating cells and tumors. In addition to the protumorigenesis pathways of lactate synthesis, circulation, and consumption, lactate-induced lactylation has been identified in recent investigations. Lactate plays crucial roles in modulating immune processes, maintaining homeostasis, and promoting metabolic reprogramming in tumors, which are processes regulated by the lactate-induced lactylation of the lysine residues of histones. In this paper, we discuss the discovery and effects of lactylation, review the published studies on how protein lactylation influences cancer growth and further explore novel treatment approaches to achieve improved antitumor effects by targeting lactylation. These findings could lead to a new approach and guidance for improving the prognosis of patients with gliomas.

Prediction of net primary productivity in the middle-to-high latitudes of Eurasia based on snow and soil temperature

Net primary productivity (NPP) is the net accumulation of organic matter by vegetation through photosynthesis and serves as a key indicator for exploring vegetation responses to climate change. Considering the remote and local impacts of soil heat capacities on vegetation growth through pathways of atmospheric circulation and land–atmosphere interaction, this paper develops a statistical prediction model for NPP from April to June (AMJ) across the middle-to-high latitudes of Eurasia. The model introduces two physically meaningful predictors: the snow water equivalent (SWE) from February to March (FM) over central Europe and the FM local soil temperature (ST). The positive phase of FM SWE triggers anomalous eastward-propagating Rossby waves, leading to an anomalous low-pressure system and cooling in the middle-to-high latitudes of Eurasia. This effect persists into spring through snow feedback to the atmosphere and affects subsequent NPP changes. The ST is closely related to the AMJ temperature and precipitation. With positive ST anomalies, the AMJ temperature and precipitation exhibit an east–west dipole anomaly distribution in this region. The single-factor prediction scheme using ST as the predictor is much better than using SWE as the predictor. Independent validation results from 2009 to 2014 demonstrate that the ST scheme alone has good predictive performance for the spatial distribution and interannual variability of NPP. The predictive skills of the multi-factor prediction schemes can be improved by about 13 % if the ST predictor is included. The findings confirm that local ST is a predictor that must be included for NPP prediction.摘要净初级生产力 (NPP) 是植被通过光合作用积累机物质的净效益, 是探索植被对气候变化响应的关键指标. 考虑到陆面热力异常通过陆气相互作用和大尺度环流对植被生长的影响, 本文研制了欧亚中高纬地区4–6月NPP预测模型. 该模型引入了两个具有明确物理意义的预测因子: 欧洲中部2–3月的雪水当量 (SWE) 和2–3月局地土壤温度 (ST). SWE的正异常会触发异常东传的Rossby波, 导致下游出现位势高度负异常并引起降温. 通过雪和温度的正反馈, 这种异常低温持续到春季并使得NPP下降. ST与随后季节的温度和降水密切相关, 当ST出现正异常时, 该地区的4–6月温度和降水呈现出东西向偶极子异常分布.对比各方案的预测效果发现, ST比SWE有更好的预测能力. 2009–2014年独立后报结果显示, ST方案对NPP的空间分布和年际变率都有很好的预测效果. 交叉检验的结果显示, 多因子方案中引入ST后能提高模型13 %的预测技巧.

Heart Transplantation Following Fontan Failure: Long-Term Survival Analysis.

Objectives: Fontan circulation presents significant challenges for patients with congenital heart disease, often necessitating heart transplantation (HTX) due to deteriorating functionality across multiple organ systems. However, the impact of prior Fontan palliation on HTX outcomes remains poorly understood, with early mortality rates suggesting a heightened risk. The aim of our study is to evaluate the long-term results after heart transplantation in patients with univentricular congenital heart disease previously palliated with Fontan circulation. Methods: A retrospective analysis was conducted on patients who underwent HTX for congenital heart disease. Patients were categorized into two groups based on the pre-HTX circulation pathway: the Failing Fontan Group (FFG) and the Biventricular Congenital Group (BCG). Data were collected from patients between 1987 and 2018. Early and late outcomes, including survival rates, were assessed and critically analyzed. Results: Of the 66 patients, 29 (43%) had a failing Fontan palliation (FFG), and 37 had biventricular congenital diseases (BCG) before heart transplantation. Early mortality (30-day) was not statistically different between the two group. The overall survival rate was 82.6 ± 13.9% at 1 year, 79.0 ± 14.9% at 5 years, 67.2 ± 17.6% at 10 years and 63.2 ± 18.2 ± at 15 years for the FFG, and 86.1 ±11.4% at 1 year, 79.5 ± 13.7% at 5 years, 75.7 ± 14.9% at 10 years, 75.7 ± 14.9% at 15 years for the BCG, with no statistically significant difference (Mantel Cox p value: 0.69, 0.89, 0.52 and 0.39, respectively). Regarding Cox-regression analysis, the long-term survival rate was not affected either by previous Fontan surgery or by the era of heart transplantation (before vs. after the year 2000). Conclusions: Although heart transplantation after Fontan palliation showed a higher risk in the early post-operative period, the medium- and long-term survival rates are comparable with biventricular circulation patients. Despite the failing Fontan patients being a challenging set of candidates for transplantation, it is a reasonable option in their treatment.

Regulation of placental amino acid transport in health and disease.

Abnormal fetal growth, i.e., intrauterine growth restriction (IUGR) or fetal growth restriction (FGR) and fetal overgrowth, is associated with increased perinatal morbidity and mortality and is strongly linked to the development of metabolic and cardiovascular disease in childhood and later in life. Emerging evidence suggests that changes in placental amino acid transport may contribute to abnormal fetal growth. This review is focused on amino acid transport in the human placenta, however, relevant animal models will be discussed to add mechanistic insights. At least 25 distinct amino acid transporters with different characteristics and substrate preferences have been identified in the human placenta. Of these, System A, transporting neutral nonessential amino acids, and System L, mediating the transport of essential amino acids, have been studied in some detail. Importantly, decreased placental Systems A and L transporter activity is strongly associated with IUGR and increased placental activity of these two amino acid transporters has been linked to fetal overgrowth in human pregnancy. An array of factors in the maternal circulation, including insulin, IGF-1, and adiponectin, and placental signaling pathways such as mTOR, have been identified as key regulators of placental Systems A and L. Studies using trophoblast-specific gene targeting in mice have provided compelling evidence that changes in placental Systems A and L are mechanistically linked to altered fetal growth. It is possible that targeting specific placental amino acid transporters or their upstream regulators represents a novel intervention to alleviate the short- and long-term consequences of abnormal fetal growth in the future.

Influence of Physical Factors on Restratification of the Upper Water Column in Antarctic Coastal Polynyas

AbstractAntarctic coastal polynyas are hotspots of biological production with intensive springtime phytoplankton blooms that strongly depend on meltwater‐induced restratification in the upper part of the water column. However, the fundamental physics that determine spatial inhomogeneity of the spring restratification remain unclear. Here, we investigate how different meltwaters affect springtime restratification and thus phytoplankton bloom in Antarctic coastal polynyas. A high‐resolution coupled ice‐shelf/sea‐ice/ocean model is used to simulate an idealized coastal polynya similar to the Terra Nova Bay Polynya, Ross Sea, Antarctica. To evaluate the contribution of various meltwater sources, we conduct sensitivity simulations altering physical factors such as alongshore winds, ice shelf basal melt, and surface freshwater runoff. Our findings indicate that sea ice meltwater from offshore is the primary buoyancy source of polynya near‐surface restratification, particularly in the outer‐polynya region where chlorophyll concentration tends to be high. Downwelling‐favorable alongshore winds can direct offshore sea ice away and prevent sea ice meltwater from entering the polynya region. Although the ice shelf basal meltwater can ascend to the polynya surface, much of it is mixed vertically over the water column and confined horizontally to a narrow coastal region, and thus does not contribute significantly to the polynya near‐surface restratification. Surface runoff from ice shelf surface melt could contribute greatly to the polynya near‐surface restratification. Nearby ice tongues and headlands strongly influence the restratification through modifying polynya circulation and meltwater transport pathways. Results of this study can help explain observed spatiotemporal variability in restratification and associated biological productivity in Antarctic coastal polynyas.

Risk factors for postoperative ventriculoperitoneal shunt requirement in pediatric patients with brain tumors invading or adjacent to CSF circulation pathways.

Hydrocephalus is a common comorbidity of brain tumors in children that may persist following brain tumor resection. This study aimed to explore perioperative risk factors associated with postoperative ventriculoperitoneal shunt (VPS) placement for tumors located at or adjacent to the CSF circulation pathway. Patients aged 0-18 years with tumors invading or adjacent to the CSF circulation pathways who underwent brain tumor resection between October 2015 and September 2021 were included in this study. The outcome metric was whether patients underwent VPS placement within 6 months of tumor resection. Patients were followed up every 3-6 months after surgery. Demographic and perioperative imaging characteristics, clinical variables, and long-term treatments, including radiotherapy or chemotherapy, were included in the analysis. Two hundred sixty-five children were included in this study. Of these patients, 38 (14.34%) underwent VPS placement within 6 months of tumor resection. One hundred thirty-two patients (49.81%) presented with preoperative hydrocephalus. Results from the multivariate analysis showed that medulloblastoma (OR 4.15, 95% CI 1.74-9.91, p = 0.001), lateral/third ventricle tumors (OR 4.07, 95% CI 1.33-12.30, p = 0.014), postoperative intraventricular hematoma (OR 3.36, 95% CI 1.53-7.38, p = 0.003), and presence of subdural hygroma in the nonoperated area within 48 hours after tumor resection (OR 2.78, 95% CI 1.15-6.74, p = 0.024) were independent risk factors for postoperative VPS placement. Postoperative lateral/third ventricle hematoma and subdural hygroma in the nonoperated area, anatomical location, and tumor histology may be potential risk factors for a postoperative VPS after brain tumor resection.

Using natural gas content of groundwater to improve the understanding of complex thermo-mineral spring systems

The varied gaseous composition of thermo-mineral waters emerging in a non-active zone reflects the diversity and complexity of groundwater pathways and provides important insights into their hydrogeological behaviours. The investigated geochemical content of complex thermo-mineral springs revealed the need to use dissolved gas contents as part of a multi-tracer approach to discriminate processes, geogenic (water–gas-rock interactions), abiotic (geological confinement, flow paths) and biotic activity influencing geochemical of groundwater along regional pathways. Irrespective of the dissolved element content or the water type, examining the overall concentration of dissolved gases enables an effective delineation of regional groundwater flow paths. Using dissolved gas content further contributed to the circumvention of some analytical challenges associated with conventional isotopic or geochemical techniques, often linked to the high concentration of elements such as iron, sulfate, sulfide or other naturally occurring elements content. The primary objectives are to analyse the gas composition of individual springs, to identify the origin of these gases in the groundwater, and to use this gas composition to improve the understanding of the flow patterns contributing to the geochemical diversity observed at the surface. From field investigations in a geologically and structurally complex area of Eastern Corsica (France), three types of gas contents are identified: (type 1) CH4 & H2S-rich, (type 2) N2-rich and (type 3) CO2-rich. The study of these dissolved gases highlights that the wide geochemical diversity of thermo-mineral waters observed here is not only related to the mineralogical composition of the local aquifer but also involves strong and cumulative interactions along deep regional circulation pathways. This approach also reveals a common deep crustal gaseous influence characterised by N2 production, which interacts during up flow with groundwater and then with the local metamorphic or sedimentary rock matrix. The groundwater’s isotopic and geochemical contents are then altered by local lithologies encountered through both abiotic and biotic interactions. Finally, at shallow depths, phreatic groundwater can add its geochemical and isotopic footprint and dilute this complex mixture before groundwater emerges as mineral spring. This paper answers the primary objectives yet further demonstrates that using dissolved gas as a tracer of groundwater flow paths allows a deeper interpretation of surface geochemical and isotopic observations, distinguishes local from regional flow paths, and provides information about processes at the origin of groundwater diversity.The combination of tools presented in this paper (i.e., geochemical, dissolved gas, and isotopic tools) allows the establishment of a reliable regional groundwater flow scheme for thermo-mineral waters in a non-active zone. This scheme is essential to improve thermo-mineral water management, and protection to ensure their sustainable quality in front of increasing anthropogenic and climatic pressures.

Quantifying Benthic δ18O Lags Across Termination 1: A Probabilistic Approach Based on Radiocarbon and Benthic δ18O Chronologies

AbstractTemporal offsets (“lags”) between benthic δ18O (δ18Ob) signals in different locations are not only a source of age model uncertainty during δ18Ob stratigraphic alignment but also provide an opportunity to improve reconstructions of deep ocean circulation change during Termination 1 (T1). While methods based on the visual identification of identical δ18Ob features have previously been used to estimate lags, here we present a novel method to calculate δ18Ob lags and their statistical uncertainties by subtracting a core's radiocarbon age model from an age model based on its δ18Ob alignment to a target stack. This method produces lag estimates as a function of time with statistical uncertainties. As an example of this approach, we calculate lags for a depth transect of 12 cores in the Brazil Margin, whose lags were described qualitatively by Lund et al. (2015, https://doi.org/10.1002/2014PA002657). Our new methodology supports a previously described lag between mid‐depth (1,802–2,296 m) and deep (2,500–2,951 m) water; specifically, we find a statistically significant lag across this boundary throughout T1, with a maximum of 2.08 kyr (95% credible interval: 1.36–2.85) at 14 ka BP. We also identify statistically significant lags between intermediate (1,105–1,627 m) and mid‐depth cores that were not previously described. Furthermore, we demonstrate that the Brazil Margin δ18Ob lags during T1 are inconsistent with a tracer transport model under modern circulation pathways (Gebbie, 2012, https://doi.org/10.1029/2011PA002273) that fits an Atlantic‐Pacific δ18Ob lag.

Polymethoxyflavones in citrus extract has a beneficial effect on hypercholesterolemia rats by promoting liver cholesterol metabolism

Ethnopharmacological relevanceHyperlipidemia is characterized by the disorder of lipid metabolism accompanied by oxidative stress damage, and low-grade inflammation, with the pathway of cholesterol and bile acid metabolic are an important triggering mechanism. Polymethoxyflavones (PMFs) are the active constituents of Aurantii Fructus Immaturus, which have many biological effects, including anti-inflammatory, antioxidant activities, anti-obesity, suppressing adipogenesis in adipocytes, and ameliorate type 2 diabetes, with potential roles for regulation of lipid metabolism. However, its associated mechanisms on hyperlipidemia remain unclear. Aim of the studyThis study aims to identify the anti-hypercholesterolemia effects and mechanisms of PMFs in a hypercholesterolemia model triggered by high-fat compounds in an excessive alcohol diet (HFD). Materials and methodsA hypercholesterolemia rat model was induced by HFD, and PMFs was intragastric administered at 125 and 250 mg/kg daily for 16 weeks. The effects of PMFs on hypercholesterolemia were assessed using serum lipids, inflammatory cytokines, and oxidative stress levels. Hematoxylin & eosin (H&E) and Oil Red O staining were performed to evaluate histopathological changes in the rat liver. The levels of total cholesterol (TC) and total bile acid (TBA) in the liver and feces were determined to evaluate lipid metabolism. RAW264.7 and BRL cells loaded with NBD-cholesterol were used to simulate the reverse cholesterol transport (RCT) process in vitro. The signaling pathway of cholesterol and bile acid metabolic was evaluated by Western Blotting (WB) and qRT-PCR. ResultsLipid metabolism disorders, oxidative stress injury, and low-grade inflammation in model rats were ameliorated by PMFs administration. Numerous vacuoles and lipid droplets in hepatocytes were markedly reduced. In vitro experiments results revealed decreased NBD-cholesterol levels in RAW264.7 cells and increased NBD-cholesterol levels in BRL cells following PMFs intervention. PMFs upregulated the expression of proteins associated with the RCT pathway, such as LXRα, ABCA1, LDLR, and SR-BI, thereby promoting TC entry into the liver. Meanwhile, the expression of proteins associated with cholesterol metabolism and efflux pathways such as CYP7A1, CYP27A1, CYP7B1, ABCG5/8, ABCB1, and BSEP were regulated, thereby promoting cholesterol metabolism. Moreover, PMFs treatment regulated the expression of proteins related to the pathway of enterohepatic circulation of bile acids, such as ASBT, OSTα, NTCP, FXR, FGF15, and FGFR4, thereby maintaining lipid metabolism. ConclusionsPMFs might ameliorate hypercholesterolemia by promoting the entry of cholesterol into the liver through the RCT pathway, followed by excretion via metabolism pathways of cholesterol and bile acid. These findings provide a promising therapeutic potential for PMFs to treat hypercholesterolemia.

Unique ocean circulation pathways reshape the Indian Ocean oxygen minimum zone with warming

Abstract. The global ocean is losing oxygen with warming. Observations and Earth system model projections, however, suggest that this global ocean deoxygenation does not equate to a simple and systematic expansion of tropical oxygen minimum zones (OMZs). Previous studies have focused on the Pacific Ocean; they showed that the outer OMZ deoxygenates and expands as oxygen supply by advective transport weakens, the OMZ core oxygenates and contracts due to a shift in the composition of the source waters supplied by slow mixing, and in between these two regimes oxygen is redistributed with little effect on OMZ volume. Here, we examine the OMZ response to warming in the Indian Ocean using an ensemble of Earth system model high-emissions scenario experiments from the Coupled Model Intercomparison Project Phase 6. We find a similar expansion–redistribution–contraction response but show that the unique ocean circulation pathways of the Indian Ocean lead to far more prominent OMZ contraction and redistribution regimes than in the Pacific Ocean. As a result, only the outermost volumes (oxygen&gt;180 µmol kg−1) expand. The Indian Ocean experiences a broad oxygenation in the southwest driven by a reduction in waters supplied by the Indonesian Throughflow in favor of high-oxygen waters supplied from the southern Indian Ocean gyre. Models also project a strong localized deoxygenation in the northern Arabian Sea due to the rapid warming and shoaling of marginal sea outflows (Red Sea and Persian Gulf) and increases in local stratification with warming. We extend the existing conceptual framework used to explain the Pacific OMZ response to interpret the response in the Indian Ocean.

Persistensi Sistem Nilai Dalihan Na Tolu dalam Ruang Rumah Tinggal Masyarakat Batak Perantauan di Yogyakarta

Title: The Persistence of the Value System of Dalihan Na Tolu within Residential Spaces of the Overseas Batak Communities in Yogyakarta The research begins with a community entity moving from old to new residential space. This study focuses on the overseas Batak community who migrated with the urge to achieve hagabeon, hamoraon, and hasangapon. Yogyakarta has become one of the destinations for the migration of the overseas Batak community. The study aims to discover how the Dalihan Na Tolu value system is reflected in the architectural patterns of the Batak community's homes in Yogyakarta. The data sources included physical evidence found in residential homes, reconstructed spatial arrangements based on observations and interviews with individuals who have been displaced from their homeland (specifically Tapanuli, North Sumatra), as well as notes and writings about the history, social, and cultural conditions of the Batak community in Yogyakarta. The gamma map technique was used to analyze the spatial depth level and position of the three functional groups in Dalihan Na Tolu. The principle of Dalihan Na Tolu persists through spatial adaptation, placing hula-hula positions in areas with high connectivity and away from circulation pathways. The persistence of the Dalihan Na Tolu value system is an attitude of respect for hula-hula.

Dissecting Earth's Magnetosphere: 3D Energy Transport in a Simulation of a Real Storm Event

AbstractWe present new analysis methods of 3D MHD output data from the Space Weather Modeling Framework during a simulated storm event. Earth's magnetosphere is identified in the simulation domain and divided based on magnetic topology and the bounding magnetopause definition. Volume energy contents and surface energy fluxes are analyzed for each subregion to track the energy transport in the system as the driving solar wind conditions change. Two energy pathways are revealed, one external and one internal. The external pathway between the magnetosheath and magnetosphere has magnetic energy flux entering the lobes and escaping through the closed field region and is consistent with previous work and theory. The internal pathway, which has never been studied in this manner, reveals magnetically dominated energy recirculating between open and closed field lines. The energy enters the lobes across the dayside magnetospheric cusps and escapes the lobes through the nightside plasmasheet boundary layer. This internal circulation directly controls the energy content in the lobes and the partitioning of the total energy between lobes and closed field line regions. Qualitative analysis of four‐field junction neighborhoods indicate the internal circulation pathway is controlled via the reconnection X‐line(s), and by extension, the interplanetary magnetic field orientation. These results allow us to make clear and quantifiable arguments about the energy dynamics of Earth's magnetosphere, and the role of the lobes as an expandable reservoir that cannot retain energy for long periods of time but can grow and shrink in energy content due to mismatch between incoming and outgoing energy flux.