Decrease In PCO2 Research Articles

Radical-directed dissociation mass spectrometry for differentiation and relative quantitation of isomeric ether-linked phosphatidylcholines

BackgroundEther-linked phosphatidylcholines (PCs) include both plasmanyl and plasmenyl PCs, which contain an ether or a vinyl ether bond at the sn-1 linkage position, respectively. Profiling and quantifying ether PCs with accurate structural information is challenging because of the common presence of isomeric and isobaric species in a lipidome. ResultsIn the present study, radical directed dissociation (RDD) from collision-induced dissociation (CID) of the bicarbonate anion adduct of ether PCs has been investigated to differentiate and relatively quantify ether PCs. Alkyl- and alkenyl- PCs give diagnostic characteristic fragment patterns that enable their confident identification and isomer differentiation. Additionally, the sn-position specific product ions have proven effective for relative quantitation among isomers in ether PCs and their isobaric PC species. Using this methodology, we successfully identified a total of 30 PC-O species, 21 PC-P species at the chain composition level, and 22 species of isobaric PC at the sn-position level in the human plasma lipid extract. The quantitative analysis revealed that ether PCs with a 20:4 fatty acyl chain are relatively more abundant in human plasma. Finally, the profile of ether PCs in type 2 diabetic (T2D) groups compared to normal control groups revealed a significant decrease in PC-O 18:1/20:5. We also found it is the PC species containing a 17-carbon fatty acyl chain, rather than their isobaric ether PCs, that shows a decreasing trend in the T2D groups. Significanceether-linked PCs are firstly investigated by RDD mass spectrometry.

Implementation and assessment of a model including mixotrophs and the carbonate cycle (Eco3M_MIX-CarbOx v1.0) in a highly dynamic Mediterranean coastal environment (Bay of Marseille, France) – Part 2: Towards a better representation of total alkalinity when modeling the carbonate system and air–sea CO2 fluxes

Abstract. The Bay of Marseille (BoM), located in the northwestern Mediterranean Sea, is affected by various hydrodynamic processes (e.g., Rhône River intrusion and upwelling events) that result in a highly complex local carbonate system. In any complex environment, the use of models is advantageous since it allows us to identify the different environmental forcings, thereby facilitating a better understanding. By combining approaches from two biogeochemical ocean models and improving the formulation of total alkalinity, we develop a more realistic representation of the carbonate system variables at high temporal resolution, which enables us to study air–sea CO2 fluxes and seawater pCO2 variations more reliably. We apply this new formulation to two particular scenarios that are typical for the BoM: (i) summer upwelling and (ii) Rhône River intrusion events. In both scenarios, our model was able to correctly reproduce the observed patterns of pCO2 variability. Summer upwelling events are typically associated with a pCO2 decrease that mainly results from decreasing near-surface temperatures. Furthermore, Rhône River intrusion events are typically associated with a pCO2 decrease, although, in this case, the pCO2 decrease results from a decrease in salinity and an overall increase in total alkalinity. While we were able to correctly represent the daily range of air–sea CO2 fluxes, the present configuration of Eco3M_MIX-CarbOx does not allow us to correctly reproduce the annual cycle of air–sea CO2 fluxes observed in the area. This pattern directly impacts our estimates of the overall yearly air–sea CO2 flux as, even if the model clearly identifies the bay as a CO2 sink, its magnitude was underestimated, which may be an indication of the limitations inherent in dimensionless models for representing air–sea CO2 fluxes.

Pre-treatments to reduce metabolism in adult green-lipped mussel, Perna canaliculus, in preparation for live transportation

Improved sustainability of aquaculture can be achieved by reducing product wastage post-harvest. Aquaculture of the green-lipped mussel, Perna canaliculus, is an important industry for New Zealand, which increasingly exports to live markets. Live transport can keep mussels fresh, but mussels could also be susceptible to handling stresses. To remedy this, pre-treatments that make mussels metabolically depressed, and thus potentially less sensitive to external stressors, were explored. As indicators of depressed metabolism, heart rate (HR), inferred cardiac output (PCO), and relative gaping magnitude (RGM) were simultaneously monitored in mussels experiencing different temperatures, dissolved oxygen levels and anaesthetic (MgCl2) concentrations to compare their efficacy in inducing suppressed metabolism of adult P. canaliculus. We found complex interactions between HR, PCO, and RGM in response to these conditions; however, overall, these response variables were significantly correlated. Mussels showed depressed HR and PCO by up to 100% at 4 °C within 2 h, with correspondingly decreased RGM of up to 48%. Similarly, mussels immersed in 40 g L−1 MgCl2 suppressed HR by up to 97%, accompanied by up to 76% decrease in PCO, and a slight increase in RGM (11%) after 2 h. While responses were variable, low DO levels suppressed HR by up to 50%, yet PCO and RGM increased two- and threefold relative to control groups. The results of the present study indicated that 4 °C and 40 g MgCl2 L−1 were more effective conditions as pre-treatments than low dissolved oxygen lower the metabolism of P. canaliculus before live transport.

Improvements in edema and microcirculation in chronic venous insufficiency with Pycnogenol® or elastic compression.

Chronic venous insufficiency (CVI) is the consequence of venous valve reflux and/or venous flow obstruction and resulting venous hypertension in the lower extremities. The aim of this prospective supplement registry study was to evaluate the efficacy of compression stockings or Pycnogenol® in controlling symptoms and edema in CVI and their efficacy on microcirculatory parameters. Two comparable groups of 30 subjects with CVI were observed for 4 months. Elastic compression was less tolerated than Pycnogenol® with 12 subjects being unable to follow the compression routine. No side effects due to supplementation were observed; tolerability of the supplementation was optimal. Ambulatory venous pressure (AVP) and refilling time (RT) at inclusion indicated a significant increase in venous pressure and reflux (refilling time <16 seconds). AVP and RT did not change after 4 months. Microcirculatory and clinical measurements were comparable at inclusion between the 2 groups. After 4 months, skin resting flux (RF) and skin PO<inf>2</inf>-PCO<inf>2</inf> were significantly improved with Pycnogenol® compared to compression (P<0.05). The significant increase in skin PO<inf>2</inf> and the decrease in PCO<inf>2</inf> after Pycnogenol® intake were ascribed to the decrease in the abnormally high skin resting flux, a sign of better perfusion and skin nutritional supply. Pycnogenol® reduced leg volume, on average by 18.3% in the evening compared to 4.4% of reduction with compression (P<0.05) showing an important effect on edema. The venous Clinical Severity Score (VCSS) and the composite symptom score (CSS) decreased significantly in the Pycnogenol® group compared to compression, indicating a better improvement in microcirculatory perfusion and nutritional supply produced by the supplementation of Pycnogenol® in comparison with compression. Pycnogenol® significantly improved microcirculation and clinical symptoms in comparison with compression. The decrease in local oxidative stress (OS) at the distal perimalleolar region with Pycnogenol® was significant in comparison with compression (P<0.05). A lower local OS is an important metabolic indication of a better capillary perfusion with better nutritional exchanges. At the end of the registry study, four small ulcerations and skin breaks in four limbs (between 3 and 5 mm of maximum diameters) were observed in the compression group. No ulcerations or skin breaks were observed in the Pycnogenol® group. Pycnogenol® relieved edema, improved microcirculation in CVI patients and reduced stationary, interstitial fluid in comparison with compression. Most symptoms of CVI are associated with interstitial water retention; the presence of extra fluid in limb tissues alters perfusion and nutrient supply. Pycnogenol® supplementation reduced water and fluid accumulation in CVI limbs and improved microcirculation and local oxidative stress thus showing important anti-edema effects.

Quantitative Assessment of Factors Contributing to Variations in Sea Surface pCO2 in the Pacific Sector of the Arctic Ocean

AbstractTo quantitatively assess seasonal variations in the partial pressure of carbon dioxide (pCO2) in the Pacific sector of the Arctic Ocean (Canada Basin and Chukchi Sea) in 2021, water temperature, salinity, chlorophyll‐a, pCO2, dissolved inorganic carbon (DIC), total alkalinity (TA), and nutrients were measured. During summer 2021, surface water pCO2 in our study area (315 ± 41 μatm) was undersaturated with respect to the atmosphere (404 ± 4 μatm), and the ocean was a sink for atmospheric CO2 (−10.5 ± 11.0 mmol C m−2 day−1). Using DIC, TA, and nutrients in the temperature minimum layer, we estimated the under‐ice pCO2 in the water during the previous winter and calculated changes in pCO2 (δpCO2) due to temperature changes, freshwater inflow, biological activity, and other factors (gas exchange and advection) from winter to summer. In the Chukchi Sea, biological activity and temperature changes had significant impacts on pCO2, whereas in the Canada Basin, the influx of freshwater caused a significant decrease in pCO2. Our results suggested that different types of freshwaters had different effects on pCO2, with sea ice meltwater having a greater effect on reducing pCO2 than river water or snowmelt water. We therefore emphasize the importance of freshwater type and proportion, as well as freshwater supply, for prediction of future pCO2 changes.

Assessing transient changes in the ocean carbon cycle during the last deglaciation through carbon isotope modeling

Abstract. Atmospheric carbon dioxide concentration (pCO2) has increased by approximately 80 ppm from the Last Glacial Maximum (LGM) to the early Holocene. The change in this atmospheric greenhouse gas is recognized as a climate system response to gradual change in insolation. Previous modeling studies suggested that the deglacial increase in atmospheric pCO2 is primarily attributed to the release of CO2 from the ocean. Additionally, it has been suggested that abrupt change in the Atlantic meridional overturning circulation (AMOC) and associated interhemispheric climate changes are involved in the release of CO2. However, understanding remains limited regarding oceanic circulation changes and the factors responsible for changes in chemical tracers in the ocean during the last deglaciation and their impact on atmospheric pCO2. In this study, we investigate the evolution of the ocean carbon cycle during the last deglaciation (21 to 11 ka BP) using three-dimensional ocean fields from the transient simulation of the MIROC 4m climate model, which exhibits abrupt AMOC changes similar to those observed in reconstructions. We investigate the reliability of simulated changes in the ocean carbon cycle by comparing the simulated carbon isotope ratios with sediment core data, and we examine potential biases and overlooked or underestimated processes in the model. Qualitatively, the modeled changes in atmospheric pCO2 are consistent with ice core records. For example, during Heinrich Stadial 1 (HS1), atmospheric pCO2 increases by 10.2 ppm, followed by a reduction of 7.0 ppm during the Bølling–Allerød (BA) period and then by an increase of 6.8 ppm during the Younger Dryas (YD) period. However, the model underestimates the changes in atmospheric pCO2 during these events compared to values derived from ice core data. Radiocarbon and stable isotope signatures (Δ14C and δ13C) indicate that the model underestimates both the activated deep-ocean ventilation and reduced efficiency of biological carbon export in the Southern Ocean and the active ventilation in the North Pacific Intermediate Water (NPIW) during HS1. The relatively small changes in simulated atmospheric pCO2 during HS1 might be attributable to these underestimations of ocean circulation variation. The changes in Δ14C associated with strengthening and weakening of the AMOC during the BA and YD periods are generally consistent with values derived from sediment core records. However, although the data indicate continuous increase in δ13C in the deep ocean throughout the YD period, the model shows the opposite trend. It suggests that the model either simulates excessive weakening of the AMOC during the YD period or has limited representation of geochemical processes, including marine ecosystem response and terrestrial carbon storage. Decomposing the factors behind the changes in ocean pCO2 reveals that variations in temperature and alkalinity have the greatest impact on change in atmospheric pCO2. Compensation for the effects of temperature and alkalinity suggests that the AMOC changes and the associated bipolar climate changes contribute to the decrease in atmospheric pCO2 during the BA and the increase in atmospheric pCO2 during the YD period.

Unmasking the Impact of Oxygenator-Induced Hypocapnia on Blood Lactate in Veno-Arterial Extracorporeal Membrane Oxygenation.

Extracorporeal membrane oxygenation (ECMO) is often associated with disturbances in acid/base status that can be triggered by the underlying pathology or the ECMO circuit itself. Extracorporeal membrane oxygenation is known to cause hypocapnia, but the impact of reduced partial pressure of carbon dioxide (pCO 2 ) on biomarkers of tissue perfusion during veno-arterial (VA)-ECMO has not been evaluated. To study the impact of low pCO 2 on perfusion indices in VA-ECMO, we placed Sprague-Dawley rats on an established VA-ECMO circuit using either an oxygen/carbon dioxide mixture (O 2 95%, CO 2 5%) or 100% O 2 delivered through the oxygenator (n = 5 per cohort). Animals receiving 100% O 2 developed a significant VA CO 2 difference (pCO 2 gap) and rising blood lactate levels that were inversely proportional to the decrease in pCO 2 values. In contrast, pCO 2 gap and lactate levels remained similar to pre-ECMO baseline levels in animals receiving the O 2 /CO 2 mixture. More importantly, there was no significant difference in venous oxygen saturation (SvO 2 ) between the two groups, suggesting that elevated blood lactate levels observed in the rats receiving 100% O 2 were a response to oxygenator induced hypocapnia and alkaline pH rather than reduced perfusion or underlying tissue hypoxia. These findings have implications in clinical and experimental extracorporeal support contexts.

The Sustained Response of Dissolved Inorganic Carbon to Urban Constructed Wetland in the Fenhe River, China: A Case Study

Sustained wetland utilization has been effective in purifying urban riverine pollutants and promoting sustainable development. However, its effect on water CO2 system remains unclear in semi-arid areas. In this study, seasonal monitoring of the carbonate system was performed at two compared stations, i.e., in constructed wetland (Xiangyun station) and its upstream (Lancun station) in a semi-arid river (the Fenhe River) in China. As indicated by the result of the sustained monthly observation from May 2020 to May 2021, riverine dissolved inorganic carbon (DIC) and partial pressure of CO2 (pCO2) reached 30.9–46.7 mg L−1 and 524–1050 μatm in Lancun station, respectively, whereas the above-described values declined significantly in Xiangyun station with the values of 24.1–39.1 mg L−1 for DIC and 188–873 μatm for pCO2. Compared with the Lancun station where the carbonate system was primarily controlled by natural factors (e.g., carbonate weathering and temperature), significant aquatic photosynthesis and calcification precipitation due to constructed wetland triggered the decrease in DIC and pCO2 and dominated their temporal variation in Xiangyun station. Thus, the large CO2 reduction arising from constructed wetlands may create vital paths for CO2 neutralization and sustainable conservation in urban rivers in arid and semi-arid areas in the future.

Paleoceanographic importance of tri- and di-unsaturated alkenones through the early phase of Cretaceous Oceanic Anoxic Event 2 from southern high latitudes of the proto-Indian Ocean

Alkenones are biomarkers derived exclusively from species of haptophyte algae. The relative abundance of di- to tri-unsaturated C37 alkenones expressed as UK'37 is widely applied as a sea surface paleotemperature proxy for Cenozoic marine sediments. However, the absence of alkatrienones prior to the Eocene has precluded application of the UK'37 proxy for assessment of Cretaceous paleoclimates. Herein, we report a C40 alkatrienone (tetraconta-9E, 16E, 23E-trien-3-one; C40:3 Et) in deep-sea sediments from southern high latitudes (International Ocean Discovery Program: IODP site U1516). This discovery extends the geologic record of alkatrienones to the late Cenomanian, ∼70 million years earlier than previous reports. The parallel occurrence of higher abundances of a C40 alkadienone (tetraconta-16E, 23E-dien-3-one; C40:2 Et) allowed calculation of the UK’40 unsaturation index, comparable to UK’37. Stratigraphic variations in the δ13C of C40:2 Et revealed an elevated (∼1.5 ‰) positive carbon isotope excursion (CIE) relative to those observed in carbonate from other OAE2 sequences likely reflecting a decrease in global pCO2. The UK’40 profile suggests a concurrent drop in sea surface temperature associated with the decline in pCO2 during the early phase of OAE2. The timing of these environmental perturbations in the southern high latitude of the proto-Indian Ocean suggests they were triggered by volcanism associated with large igneous province (LIP) formation.

Seaweed farming environments do not always function as CO2 sink under synergistic influence of macroalgae and microorganisms

Seaweed farming contributes substantial amounts of organic carbon to the ocean, part of which can be locked for a long term in the ocean and perform the function of ocean carbon sequestration, and the other part can be converted into inorganic carbon through microbial mineralization and aerobic respiration, affecting the pCO2, pHT and dissolved oxygen of seawater. It is generally believed that seaweed farming will cause the seawater to become a sink of CO2 due to carbon fixation by macroalgal photosynthesis. However, little attention has been paid to the fact that seaweed farming environment may sometimes become a source rather than a sink of CO2. Here, through in-situ mesocosm cultivation experiments and eight field investigations covering different kelp growth stages in an intensive farming area in China, we found that compared with the surrounding seawater without kelps, the seawater at the fast-growth stage of kelp was a sink of CO2 (pCO2 decreased by 17−73 μatm), but became a source of CO2 at the aging stage of kelp (pCO2 increased by 20−37 μatm). Concurrently, seawater pHT experienced a transition from increase (by 0.02−0.08) to decline (by 0.03−0.04). In-situ mesocosm cultivation experiments showed that the positive environmental effects (i.e., pCO2 decrease and pHT increase) induced by kelps at the early growth stage could be offset within only 3 days at the late-growth and aging stages. The release of dissolved organic carbon by kelps at the late growth stage increased significantly, supporting the enhancement in microbial abundance and respiration, which was manifested by the remarkable decrease in seawater dissolved oxygen, ultimately leading to CO2 release exceeding photosynthetic CO2 absorption. This study suggests that mature farmed kelps should be harvested in time to best utilize their carbon sink function and environmental benefits, which has guiding significance for the rational management of seaweed farming.

The Effect of High Fat Formula Liquid Feeding on the Value of PCO2 and Duration of Use of Respiratory Aids for COVID-19 Patients with Critical Illness

Background: In December 2019, WHO announced the outbreak of COVID-19 disease caused by SARSCOV2. COVID-19 is a global pandemic characterized by high morbidity and mortality. SARS-CoV2 with there are many symptoms, about 20-26% of patients with COVID-19 pneumonia become severe or critical, requiring hospitalization for respiratory support. In Indonesia, COVID-19 has been increasing since 2020, and on February 2021, the Covid-19.go.id page had 1.157.837 confirmed cases, 176.291 active cases, 949.990 recovered, and 31.556 death cases. Acute respiratory complications requiring treatment in the intensive care unit are the main cause of high morbidity and mortality in patients with COVID-19. Nutrition therapy has influenced for outcomes of COVID-19 patients. Methods: The primary purpose of this study was to compare the value of PCO2, and duration of use of respiratory support for COVID-19 patients with critical illness. The result compared the COVID-19 patients who had been administered with high lipid formula nutrition (PULMOSOL) and patients who had been administered with standard liquid formula nutrition. The rate of the intervention group that experienced an increase in PCO2 was 55.6%, higher than those who experienced a decrease in PCO2 (50%). Results: Based on the analysis results, there was no difference in the administration of PULMOSOL and standard formula based on PCO2 in the use of ventilators in COVID-19 critically ill patients in Dr. M Djamil Padang General Hospital (p&gt;0.05) with HR = 1.39 (95% CI 1.55-3.55). In patients with increased PCO2, it was found that the intervention group who died was 55.6%, lower compared to the control group (62.5%). The same in patients with decreased pCO2, group the intervention group who died was 50.0%, higher than the control group (40%). Conclusion: Statistical tests demonstrated there was no relationship between the administration of PULMOSOL and the outcome of critically ill COVID-19 (p&gt;0.05). Keywords: Covid-19, critically ill, nutrition, high lipid formula

NBCe1-B/C-knockout mice exhibit an impaired respiratory response and an enhanced renal response to metabolic acidosis.

The sodium-bicarbonate cotransporter (NBCe1) has three primary variants: NBCe1-A, -B and -C. NBCe1-A is expressed in renal proximal tubules in the cortical labyrinth, where it is essential for reclaiming filtered bicarbonate, such that NBCe1-A knockout mice are congenitally acidemic. NBCe1-B and -C variants are expressed in chemosensitive regions of the brainstem, while NBCe1-B is also expressed in renal proximal tubules located in the outer medulla. Although mice lacking NBCe1-B/C (KOb/c) exhibit a normal plasma pH at baseline, the distribution of NBCe1-B/C indicates that these variants could play a role in both the rapid respiratory and slower renal responses to metabolic acidosis (MAc). Therefore, in this study we used an integrative physiologic approach to investigate the response of KOb/c mice to MAc. By means of unanesthetized whole-body plethysmography and blood-gas analysis, we demonstrate that the respiratory response to MAc (increase in minute volume, decrease in pCO2) is impaired in KOb/c mice leading to a greater severity of acidemia after 1day of MAc. Despite this respiratory impairment, the recovery of plasma pH after 3-days of MAc remained intact in KOb/c mice. Using data gathered from mice housed in metabolic cages we demonstrate a greater elevation of renal ammonium excretion and greater downregulation of the ammonia recycling enzyme glutamine synthetase in KOb/c mice on day 2 of MAc, consistent with greater renal acid-excretion. We conclude that KOb/c mice are ultimately able to defend plasma pH during MAc, but that the integrated response is disturbed such that the burden of work shifts from the respiratory system to the kidneys, delaying the recovery of pH.

Comparison of hemodynamic consequences of hand ventilation versus machine ventilation for transportation of post-operative pediatric cardiac patients.

Hemodynamic monitoring during in-hospital transport of intubated patients is vital; however, no prospective randomized trials have evaluated the hemodynamic consequences of hand versus machine ventilation during transport among pediatric patients' post-cardiac surgery. The authors hypothesized that manual ventilation after pediatric cardiac surgery would alter hemodynamic and arterial blood gas (ABG) parameters during transport compared to mechanical ventilation. A prospective randomized trial. Tertiary cardiac care hospital. Pediatric cardiac surgery patients. One hundred intubated pediatric patients were randomized to hand or machine ventilation immediately post-cardiac surgery during transport from the operating room to the pediatric post-operative intensive care unit (PICU). Hemodynamic variables, including end-tidal CO2 (ETCO2), oxygen saturation, heart rate, systolic blood pressure (SBP), diastolic blood pressure (DBP), peak airway pressure (Ppeak), and mean airway pressure (Pmean), were measured at origin, during transport, and at the destination. ABG was measured before and upon arrival in the PICU, and adverse events were recorded. The Chi-square test and independent t-test were used for comparison of categorical and continuous parameters, respectively. The mean transport time was comparable between hand-ventilated (5.77 ± 1.46 min) and machine-ventilated (5.96 ± 1.19 min) groups (P = 0.47). ETCO2 consistently dropped during transport and after shifting in the hand-ventilated group, with significantly higher ETCO2 excursion than in machine-ventilated patients (P < 0.05). SBP and DBP significantly decreased during transport (at 5 and 6 min intervals) and after shifting in hand-ventilated patients than in the other group (P < 0.05). Additionally, after shifting, a significant increase in Ppeak (P < 0.001), Pmean (P < 0.001), and pH (P < 0.001), and a decrease in pCO2 (P = 0.0072) was observed in hand-ventilated patients than machine-ventilated patients. No adverse event was noted during either mode of ventilation. Hand ventilation leads to more significant variation in ABG and hemodynamic parameters than machine ventilation in pediatric patients during transport post-cardiac surgery. Therefore, using a mechanical ventilator is the preferred method for transporting post-operative pediatric cardiac patients.

Proxy‐Model Comparison for the Eocene‐Oligocene Transition in Southern High Latitudes

AbstractThe Eocene‐Oligocene transition (EOT) marks the shift from greenhouse to icehouse conditions at 34 Ma, when a permanent ice sheet developed on Antarctica. Climate modeling studies have recently assessed the drivers of the transition globally. Here we revisit those experiments for a detailed study of the southern high latitudes in comparison to the growing number of mean annual sea surface temperature (SST) and mean air temperature (MAT) proxy reconstructions, allowing us to assess proxy‐model temperature agreement and refine estimates for the magnitude of the pCO2 forcing of the EOT. We compile and update published proxy temperature records on and around Antarctica for the late Eocene (38–34 Ma) and early Oligocene (34–30 Ma). Compiled SST proxies cool by up to 3°C and MAT by up to 4°C between the timeslices. Proxy data were compared to previous climate model simulations representing pre‐ and post‐EOT, typically forced with a halving of pCO2. We scaled the model outputs to identify the magnitude of pCO2 change needed to drive a commensurate change in temperature to best fit the temperature proxies. The multi‐model ensemble needs a 30 or 33% decrease in pCO2, to best fit MAT or SST proxies respectively. These proxy‐model intercomparisons identify declining pCO2 as the primary forcing of EOT cooling, with a magnitude (200 or 243 ppmv) approaching that of the pCO2 proxies (150 ppmv). However individual model estimates span a decrease of 66–375 ppmv, thus proxy‐model uncertainties are dominated by model divergence.

EVALUATION OF THE EFFICACY OF DIFFERENT RUMEN BUFFERS ON PREVENTION OF RUMINAL ACIDOSIS IN GOATS

This study was realized to evaluate the efficacy of dietary supplementation of sodium bicarbonate plus magnesium oxide "MgO", calcareous marine algae (AcidBuf) and essential oils (Actifor®Boost) on the animal performance and prevention of ruminal acidosis in goats moreover, evaluation the diagnostic accuracy of some biochemical parameters including blood pH, total antioxidant capacity (TAC), bicarbonate (HCO3-), partial pressure of carbon dioxide (pCO2), beta-hydroxybutyric acid (βHBA) and plasma L-lactate versus ruminal pH in diagnosis of ruminal acidosis. A total of 30 goats were divided into five equal groups (G1-5) according to the type of dietary treatment. G1 served as a control group and fed the concentrate diet only, G2 fed the concentrate diet supplemented with 10 g Na bicarbonate plus 4g MgO, G3 supplemented with 4g AcidBuf, G4 supplemented with 10 g Na bicarbonate plus 4g MgO plus 4g AcidBuf and G5 supplemented with 1g Actifor® boost/head/day for five days. Tachycardia, tachypnea and decreased ruminal motility were recorded in G1 only. The ruminal pH tended to return to its toward normal for G3 and G4 with a mean of (6.3±0.03 and 6.3±0.01, respectively) which significantly higher than those of G1 and G2 (6.19±0.01 and 6.17±0.02 respectively). A significant increase in plasma L-lactate and a significant decrease in blood pH, HCO3-, pCO2, TAC, and βHBA were recorded in G1 when compared with other groups. Calcareous marine algae with or without adding other compounds found to be a promising rumen buffer agent, moreover TAC and plasma L-lactate showed better diagnostic performance versus rumen pH in the diagnosis of ruminal acidosis.

Etiology of diarrhoea among adult buffaloes (Bubalus bubalis) and their impact on haemato-biochemical and mineral profile

80 adult buffaloes suffering from diarrhea from sub-tropical and temperate zones of Jammu division were selected to establish etiology and to evaluate hemato-biochemical and mineral alterations. Clinico-haemato-biochemical,mineral and faecal evaluation was carried to relate alterations with respect to etiologies of diarrhoea. Strongyle infection was recorded among 32.5% buffaloes followed by amphistomiasis (18.75%), coccidiosis (7.5%), salmonellosis (7.5%) and balantidiasis (7.5%). 23.45% of affected buffaloes were placed under miscellaneous group as definite etiology could not be established. Season-wise, analysis revealed maximum prevalence of diarrhoea during rainy season (47.5%) followed by summer (35%) and winter (17.5%). Animals of 1 to 3 years age group had higher prevalence of coccidiosis (50%), strongyle infection (46.1%) and salmonellosis (37.5%) whereas, &gt;6 years age group had higher prevalence amphistomiasis (66.7%) and balantidiasis (50%). Significant reduction (P&lt;0.05) in hemoglobin, TEC, TPP, albumin, sodium, chloride, calcium and copper levels was recorded along with significant increase in plasma fibrinogen level among the diarrheic buffaloes. The results of blood gas analysis revealed significant (P&lt;0.05) decrease in pH, pCO2, HCO3 and base excess and significant (P&lt;0.05) increase in anion gap. Since, diarrhoea is a multifactorial disease leading to varying clinical signs, haemato-biochemical, mineral and blood gas changes which needs to be evaluated before recommending therapeutic regimen for recovery.

Drivers of Late Miocene Tropical Sea Surface Cooling: A New Perspective From the Equatorial Indian Ocean

AbstractDuring the late Miocene, global cooling occurred alongside the establishment of near‐modern terrestrial and marine ecosystems. Significant (3°C–5°C) sea surface cooling from 7.5 to 5.5 Ma is recorded by proxies at midlatitudes to high latitudes, yet the magnitude of tropical cooling and the role of atmospheric carbon dioxide (pCO2) in driving this trend are debated. Here, we present a new orbital‐resolution sea surface temperature (SST) record spanning the late Miocene to earliest Pliocene (9–5 Ma) from the eastern equatorial Indian Ocean (International Ocean Discovery Program Site U1443) based on Mg/Ca ratios measured in tests of the planktic foraminifer Trilobatus trilobus. Our SST record reveals a 3.2°C decrease from 7.4 to 5.8 Ma, significantly increasing previous estimates of late Miocene tropical cooling. Analysis of orbital‐scale variability shows that before the onset of cooling, SST variations were dominated by precession‐band (19–23 kyr) variability, whereas tropical temperature became highly sensitive to obliquity (41 kyr) after 7.5 Ma, suggesting an increase in high‐latitude forcing. We compare a revised global SST database with new paleoclimate model simulations and show that a pCO2 decrease from 560 to 300 ppm, in the range suggested by pCO2 proxy records, could explain most of the late Miocene sea surface cooling observed at Site U1443. Using our new Site U1443 record as representative of tropical SST evolution, estimated meridional SST gradients suggest a much more modest increase over the late Miocene than previously suggested, in agreement with modeled meridional SST gradients.

Cerebrospinal fluid and arterial acid–base equilibria in spontaneously breathing third-trimester pregnant women

BackgroundAcid–base status in full-term pregnant women is characterised by hypocapnic alkalosis. Whether this respiratory alkalosis is primary or consequent to changes in CSF electrolytes is not clear. MethodsWe enrolled third-trimester pregnant women (pregnant group) and healthy, non-pregnant women of childbearing age (controls) undergoing spinal anaesthesia for Caesarean delivery and elective surgery, respectively. Electrolytes, strong ion difference (SID), partial pressure of carbon dioxide (PaCO2), and pH were measured in simultaneously collected CSF and arterial blood samples. ResultsAll pregnant women (20) were hypocapnic, whilst only four (30%) of the controls (13) had an arterial PaCO2 <4.7 kPa (P<0.001). The incidence of hypocapnic alkalosis was higher in the pregnant group (65% vs 8%; P=0.001). The CSF-to-plasma Pco2 difference was significantly higher in pregnant women (1.5 [0.3] vs 1.0 [0.4] kPa; P<0.001), mainly because of a decrease in arterial Pco2 (3.9 [0.3] vs 4.9 [0.5] kPa; P<0.001). Similarly, the CSF-to-plasma difference in SID was less negative in pregnant women (–7.8 [1.4] vs –11.4 [2.3] mM; P<0.001), mainly because of a decreased arterial SID (31.5 [1.2] vs 36.1 [1.9] mM; P<0.001). The major determinant of the reduced plasma SID of pregnant women was a relative increase in plasma chloride compared with sodium. ConclusionsPrimary hypocapnic alkalosis characterises third-trimester pregnant women leading to chronic acid–base adaptations of CSF and plasma. The compensatory SID reduction, mainly sustained by an increase in chloride concentration, is more pronounced in plasma than in CSF, as the decrease in Pco2 is more marked in this compartment. Clinical trial registrationNCT03496311.

Variation of Saturation Indices (SIcal) with respect to Calcite Mineral at Kalisirah and Jumbleng Springs, South Gombong Karst, Central Java, Indonesia

This research was conducted in two main springs, namely Kalisirah and Jumbleng springs, located on the north side of the South Gombong karst area, Central Java, Indonesia. The objective of this study was to determine the temporal variation of the saturation indices with respect to the mineral calcite in the two springs. Water samples were taken 24 times at each spring during dry, rainy, and flood events. Electrical Conductivity (EC), pH, temperature, calcium (Ca2+) and bicarbonate (HCO3 −) were measured directly in the field, while other major elements such as Mg2+, Na+, K+, SO4 2−, Cl− were analyzed in the laboratory. Furthermore, the calculation of the Saturation Indices with respect to the calcite mineral (SIcal) and carbon dioxide partial pressure (logPCO2) was carried out. The analysis results show that temporally, the SIcal value is generally higher during low discharge (dry season) and decreased during high discharge (rainy season). When compared, Jumbleng Springs has a stronger relationship between decreased discharge and an increase in SIcal. Meanwhile, the variation of SIcal increase (during the dry season) is also followed by a decrease in log PCO2, which indicates the dominance of the calcite precipitation process when the carbon dioxide content in the water is minimal.

Modeling the sea-surface pCO2 of the central Bay of Bengal region using machine learning algorithms

The present study explores the capabilities of advanced machine learning algorithms in predicting the sea-surface pCO2 (partial pressure of carbon dioxide) in the open oceans of the Bay of Bengal (BoB). We collect the available observations (outside EEZ (Exclusive Economic Zone)) from the cruise tracks and the mooring stations. Due to the paucity of data in the BoB, we attempt to predict pCO2 based on the Sea Surface Temperature (SST) and the Sea Surface Salinity (SSS). Comparing the MLR, the ANN, and the XGBoost algorithm against a common dataset reveals that the XGBoost performs the best for predicting the sea-surface pCO2 in the BoB. Using the satellite-derived SST and SSS, we predict the sea-surface pCO2 using the XGBoost model and compare the same with the in-situ observations. The model performs satisfactorily, having a correlation of 0.75 and the RMSE of ±12.23μatm. Further using this model, we emulate the monthly variations in the sea-surface pCO2 for the central BoB between 2010–2019. Using the satellite data, we show that the central BoB is warming at a rate of 0.0175 °C per year, whereas the SSS decreases at a rate of -0.0088 PSU per year. The modeled pCO2 shows a declination at a rate of −0.4852 μatm per year. We perform sensitivity experiments to find that the variations in SST and SSS contribute ≈ 41% and ≈ 37% to the declining trends of the pCO2 for the last decade. Seasonal analysis shows that the pre-monsoon season has the highest rate of decrease of the sea-surface pCO2.