Salt Balance Research Articles

#3840 THE SYSTEMIC AND RENAL HAEMODYNAMIC EFFECTS OF APELIN IN HEALTH AND CHRONIC KIDNEY DISEASE

Abstract Background and Aims Chronic kidney disease (CKD) is a leading cause of global morbidity and mortality and is independently associated with cardiovascular disease. Indeed, patients with CKD are more likely to die of cardiovascular disease than they are to progress to kidney failure. Despite current standard of care, outcomes remain poor and newer therapies are needed. Apelin, an endothelium-dependent vasodilator and potent inotrope, is a potential novel treatment for CKD. There are no clinical studies of the renal actions of apelin, but pre-clinical data show that it regulates glomerular haemodynamics and promotes aquaresis. We investigated the cardiovascular and renal actions of apelin in healthy volunteers and in patients with CKD. Method Patients with stable, non-diabetic CKD and age- and sex-matched healthy volunteers were recruited to a prospective, randomised, double-blind and placebo-controlled study. Subjects received either pyroglutamated apelin-13 ([Pyr1]apelin-13, 1 nmol/min and 30 nmol/min) or placebo on two separate visits. Cardiovascular assessments included blood pressure, impedance cardiography and pulse wave velocity; iohexol and para-aminohippurate clearance were used to assess glomerular filtration rate (GFR) and renal blood flow, respectively. Tubular function was examined via urinary sodium, potassium and free water excretion. Results Twelve patients with CKD and 12 healthy volunteers were recruited and completed both phases of the study protocol. Baseline characteristics are shown in Table 1. Whilst infusion of 1 nmol/min [Pyr1]apelin-13 did not affect systemic haemodynamics, 30 nmol/min [Pyr1]apelin-13 led to significant changes. Compared to placebo, mean arterial pressure fell by 3 mmHg and 4 mmHg in health and CKD, respectively (p<0.05 for both groups), and systemic vascular resistance index fell by 309 dynes*s*cm−5 m2 and 407 dynes*s*cm−5 m2, respectively (p<0.01 for both groups). Cardiac index increased by 0.3 L/min/m2 and 0.2 L/min/m2, respectively (p<0.05 for both groups compared to placebo). In contrast, both 1 nmol/min and 30 nmol/min [Pyr1]apelin-13 had similar effects on renal haemodynamics. Effective renal blood flow increased by ∼15% in health and CKD (p<0.01 compared to placebo for both groups). GFR fell by ∼4 mL/min compared to placebo in patients with CKD (p<0.01) but we observed no change in healthy volunteers. As a result of these changes in effective renal blood flow and GFR, filtration fraction fell by ∼3% in CKD, reflected by a fall in proteinuria of ∼25% (p<0.001 compared to placebo for both). Both low and high doses of [Pyr1]apelin-13 promoted natriuresis and free water clearance in health and CKD. In comparison to placebo, sodium excretion increased by ∼30% and free water clearance by ∼15% in both groups (p<0.05 for all comparisons). Overall, the effects of apelin were prolonged in CKD. Conclusion Apelin offers systemic and renal haemodynamic benefits to patients with CKD. If these effects were maintained longer-term they would translate to improved cardiovascular and renal outcomes in this at-risk patient group. Clinical trials of long-acting, oral apelin analogues are now justified in CKD and other conditions with impaired salt and water balance.

Impact of Salinity, Elevated Temperature, and Their Interaction with the Photosynthetic Efficiency of Halophyte Crop Chenopodium quinoa Willd

Chenopodium quinoa is a genetically diverse crop that can adapt to a wide range of environments, including temperatures and salinities. However, only a few studies have assessed the combined effects of two or more environmental factors on C. quinoa. Here, we investigated the effects of salinity (300 mM NaCl), elevated temperature (35 °C), and their interaction with growth, water–salt balance, the efficiency of photosystem II (PSII), the activity of cyclic electron transport (CET) around photosystem I (PSI), Rubisco and PEPC enzyme content, and the expression of photosynthetic genes. We found that elevated temperature did not decrease the biomass but caused a significant increase in the water and potassium content of C. quinoa leaves. The decrease in PSII efficiency under elevated temperature was accompanied by an increase in the expression of genes encoding the components of PSII (psbA) and linear electron transport (FDI), as well as the main photosynthetic protein Rubisco (rbcL). Moreover, the strongest effect was induced by the combined effect of elevated temperature and salinity, which induced high oxidative stress (a threefold increase in MDA), a threefold decrease in the biomass, a twofold decrease in PSII efficiency, and a two- to eightfold decrease in the expression of the photosynthetic genes psbA, FDI, and rbcL. PSI was more tolerant to all forms of stress; however, the combined effect of elevated temperature and salinity downregulated the expression of PGR5 and FNR1, which may diminish the role of PGR5/PGRL1-dependent CET in favor of the NDH-dependent CET of PSI. The obtained data on the functioning of photosystems and the expression of photosynthetic genes under combined stress (elevated temperature and salinity) can make a significant contribution to understanding the mechanisms of tolerance of C. quinoa to multiple stresses under climate change conditions.

VARIATIONS IN THE PERCEPTION OF BITTER TASTE MAY MODULATE THE RISK OF HYPERTENSION

Objective: The perception of bitter taste conditioned by the TAS2R38 gene (combined Proline/Alanine/Valine and Isoleucine phenotypes) may be associated with food consumption. Individuals with one copy of PAV are bitter tasters, with two copies of AVI are non-bitter tasters, and with AAV < AAI < PAI are intermediate bitter tasters. Consumption salt balance is determined by the function of the epithelial sodium channels that lead to its preference and the bitter taste receptors associated with its aversion. In turn, a chronic high salt intake was associated with the inhibition of bitter receptors with less salty taste aversion leading to potential higher consumption and risk of hypertension. The objective was to evaluate the influence of bitter taste perception on the risk of arterial hypertension. Design and method: DNA from 339 individuals was quantified and genotyped by reverse transcription followed by polymerase chain reaction (RT-PCR). Blood pressure was determined by standard methods. Arterial hypertension was diagnosed in 141 individuals who were compared with 198 normotensive individuals. Thyroid functional status is determined by clinical history, physical examination, FT4, FT3, TSH, antiperoxidase, antithyroglobulin, and TRAB antibodies. Hypothyroidism at 33.3%, hyperthyroidism 14.3% and euthyroidism 52.35%. Statistics: chi2 and t-Student, considering significance <0.05. Results: The frequencies of the TAS2R38 diplotypes were: PVI/PVI (26%); PVV/PVI (0.9%); PVV/AVI(10.6%); PVV/AVV(0.9%); AVV/AVV(2.4%); PAI/PVI(0.3%); PAV/PVI(5.95%); PAV/AVI(37.5%); AAV/AAV(12.7%); PAV/AAV(2.75%) and PAV/AAI(0.3%). The TAS2R38 AAV/AAV and PAV/AAV diplotypes showed a lower risk of hypertension adjusted for thyroid dysfunction, compared to the remaining diplotypes of this gene, with OR = 0.458[0.236-0.887], p = 0.021. Other diplotypes showed no significant association. Conclusions: Individuals with bitter tasting associated with AAV genotypes may be less likely to develop hypertension compared to other bitter tasters. The lower risk of hypertension in these genotypes may be associated with greater functionality of bitter taste receptors associated with aversion to salt intake. In conclusion, the genetic polymorphisms of the bitter taste gene may influence the risk for arterial hypertension and may therefore be considered potential future therapeutic targets. The absence of bitter-insensitive individuals (AVI/AVI) in this sample limits the understanding of the influence of these genotypes on the risk of hypertension.

On the ability of OMIP models to simulate the ocean mixed layer depth and its seasonal cycle in the Arctic Ocean

We evaluate the skills of ocean–sea ice general circulation models involved in the Ocean Modeling Intercomparison Project in simulating the ocean mixed layer depth and its seasonal cycle in the Arctic region. During summer months, all models consistently underestimate the mixed layer depth compared to observational data from the Monthly Isopycnal Mixed layer Ocean Climatology and the Ice Tethered Profilers. In fall and winter, the models exhibit great variability compared to observational data, and inter-model comparison reveals differences up to several tens of meters. We analyze the origin of the fall and winter model biases in ice-covered regions, where the seasonal cycle of the surface salinity and mixed layer depth is strongly influenced by brine rejection resulting from ocean–sea ice interactions.Focusing first on the central Arctic Ocean, defined here as the region north of 80° N, we show that all models simulate more or less the same vertical sea ice mass balance and thus similar salt fluxes into the ocean during sea ice freezing. Furthermore, the model ensemble features a strong relationship between the stratification profile in September and the mixed layer depth at the end of winter. The models whose stratification compares the best to observational data also display the most realistic values of the mixed layer depth at the end of winter. We argue that the discrepancies between models are therefore not so much linked to the surface salt balance but rather to the accuracy with which those models reproduce the vertical salinity profile. In short, a weakly stratified ocean tends to create a deep mixed layer, while strong stratification leads to a shallow mixed layer. To substantiate this conclusion, we apply a simple conceptual model, which simulates the month-to-month evolution of the mixed layer depth using as input the vertical salinity gradients and the surface salt fluxes from general circulation models. Quite surprisingly, this simplified dynamics captures very well the behavior of the general circulation models, emphasizing the role of the different vertical stratification in the control of the mixed layer depth. Furthermore, this interplay may also significantly account for the large mixed layer biases observed in other ice-covered regions of the pan-Arctic seas, even though sea–ice ocean interaction is not the only driver of mixed layer variability in fall and winter there.

Self-maintaining macrophages within the kidney contribute to salt and water balance by modulating kidney sympathetic nerve activity

The kidney is critical in controlling salt and water balance, with the interstitium involved with a variety of components including immune cells in steady state. However, the roles of resident immune cells in kidney physiology are largely unknown. To help unravel some of these unknowns, we employed cell fate mapping, and identified a population of embryo-derived self-maintaining macrophages (SM-MØ) that were independent of the bone marrow in adult mouse kidneys. This kidney-specific SM-MØ population was distinctive from the kidney monocyte-derived macrophages in transcriptome and in their distribution. Specifically, the SM-MØ highly expressed nerve-associated genes; high-resolution confocal microscopy revealed that the SM-MØ in the cortex were in close association with sympathetic nerves and there was a dynamical interaction between macrophages and sympathetic nerves when live kidney sections were monitored. Kidney-specific depletion of the SM-MØ resulted in reduced sympathetic distribution and tone, leading to reduced renin secretion, increased glomerular filtration rate and solute diuresis, which caused salt decompensation and significant weight loss under a low-salt diet challenge. Supplementation of L-3,4-dihydroxyphenylserine which is converted to norepinephrine invivo rescued the phenotype of SM-MØ-depleted mice. Thus, our findings provide insights in kidney macrophage heterogeneity and address a non-canonical role of macrophages in kidney physiology. In contrast to the well-appreciated way of central regulation, local regulation of sympathetic nerve distribution and activities in the kidney was uncovered.

Random ionic polymers: Salt-triggered reversible vesicular self-assembly in water

NaCl salt as an external stimulus triggers the self-assembly of ionic polymers and offers a convenient route to structuring vesicular reversible polymeric nanoparticles. In this contribution, amphiphilic random imidazolium ionic polymers are synthesized by roping the partial anion exchange and the choice of N-substituent. These polymers are evaluated for their self-assembly behavior in water, and it is strengthened by dye encapsulation application in water through self-assembly. The effects of salt and pH study demonstrated the reversibility of self-assembly. The self-assembled nano-aggregates are thermoresponsive at the upper critical solution temperature (UCST) (Cp 47 °C). The synergic balance between hydrogen bonding and ionic self-assembly is attributed to the constituents in the macromolecular structure, making these polyionic liquids (PILs) a “smart” responsive system in water upon the addition of external stimuli, such as NaCl and KPF6. This self-assembly is acquired with partial anion exchange and salt balance in the water. The unusual interfacial activity of polymer to form a regular shape eventually to surfaces organic dye molecule serving as a type of stabilizer or scavenger evidenced by nano-size and vesicular morphology analysis.

The Physiology of Migraine and its Prevention by Nutrition

Migraine is a genetic condition associated with hypersensitive sensory neurons, more sensory neuronal connections, and different electrical properties than a non-migraine brain[1, 2]. Migraineurs waste 50% more sodium in their urine than typical subjects[3]. The most prominent migraine related genetic variants are associated with critical ionic channels that operate the brain’s electrical functions: action potential, resting potential, the delivery of neurotransmitters, and the resetting of membrane potential[4, 5]. Migraineurs’ brains are very sensitive to electrolyte imbalance as a result of channelopathy[6-8] and because of carbohydrate sensitivity. Migraineurs tend to end up with metabolic syndrome. In this paper I present case studies based on findings in a Facebook migraine group with over thirteen thousand migraine members, who have been able to abort and prevent all of their migraines while also tapering off of all of their migraine medications, by applying only nutritional and hydration changes.1. Ambrosini, A. and J. Schoenen, The electrophysiology of migraine. Curr Opin Neurol, 2003. 16(3): p. 327-31. 2. Tso, A.R., et al., The anterior insula shows heightened interictal intrinsic connectivity in migraine without aura. Neurology, 2015: p. 1043-50. 3. Campbell, D.A., E.M. Tonks, and K.M. Hay, An Investigation of the Salt and Water Balance in Migraine. British Medical Journal, 1951: p. 1424-1429. 4. Science, W.I.o. The Human Gene Database. GeneCards: The Human Gene Database 2017 [cited 2017 1/28/2017]; The Human Genome Database]. Available from: http://www.genecards.org . 5. Liu, H., et al., Resting state brain activity in patients with migraine: a magnetoencephalography study. The Journal of Headache and Pain, 2015. 16(1): p. 42. 6. Lee, J.-Y. and M. Kim, Current Issues in Migraine Genetics. J Clin Neurol, 2005. 1(1): p. 8-13. 7. Catterall, W.A., et al., Inherited Neuronal Ion Channelopathies: New Windows on Complex Neurological Diseases. The Journal of Neuroscience, 2008. 28(46): p. 11768-11777. 8. Longo, D.L., et al., Harrison's Manual of Medicine 18th Edition. 2013, New York: McGraw Hill Medical. Not funded This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Cystic Fibrosis-Related Diabetes Workshop: Research Priorities Spanning Disease Pathophysiology, Diagnosis, and Outcomes.

Cystic fibrosis (CF) is a recessive disorder arising from mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR) protein. CFTR is expressed in numerous tissues, with high expression in the airways, small and large intestine, pancreatic and hepatobiliary ducts, and male reproductive tract. CFTR loss in these tissues disrupts regulation of salt, bicarbonate, and water balance across their epithelia, resulting in a systemic disorder with progressive organ dysfunction and damage. Pancreatic exocrine damage ultimately manifests as pancreatic exocrine insufficiency that begins as early as infancy. Pancreatic remodeling accompanies this early damage, during which abnormal glucose tolerance can be observed in toddlers. With increasing age, however, insulin secretion defects progress such that CF-related diabetes (CFRD) occurs in 20% of teens and up to half of adults with CF. The relevance of CFRD is highlighted by its association with increased morbidity, mortality, and patient burden. While clinical research on CFRD has greatly assisted in the care of individuals with CFRD, key knowledge gaps on CFRD pathogenesis remain. Furthermore, the wide use of CFTR modulators to restore CFTR activity is changing the CFRD clinical landscape and the field's understanding of CFRD pathogenesis. For these reasons, the National Institute of Diabetes and Digestive and Kidney Diseases and the Cystic Fibrosis Foundation sponsored a CFRD Scientific Workshop, 23-25 June 2021, to define knowledge gaps and needed research areas. This article describes the findings from this workshop and plots a path for CFRD research that is needed over the next decade.

Effects of traumatic brain injury on blood pressure regulation and cardio-renal function in rats

Traumatic Brain Injury (TBI) affects around 68 million people worldwide annually. While the neurologic effects of TBI have been extensively studied, potential effects on the autonomic nervous system have received less attention, despite clinical observations of autonomic dysfunction. We therefore sought to develop a rat model of repeated traumatic brain injury to examine the effects on cardiovascular and renal regulation, and we hypothesized that TBI would result in autonomic dysregulation of cardio-renal function. TBI was induced in male rats (250-300 gBW) under brief isoflurane anesthesia by dropping a 245g weight from a height of 1-1.5 meters onto the mid-sagittal area of the skull while the rat was suspended on a perforated tear-away platform. In the first series of experiments, blood pressure was measured continuously by telemetry over a two-week period, while rats were subjected to three successive injuries, each separated by 48 hours (repeated TBI, rTBI). Mean blood pressure was found to increase by about 7 mmHg following the third TBI (104.0 ± 1.1 to 111.0 ± 1.3 mmHg; p < 0.001, n=9). Though mild, the elevation in blood pressure was highly consistent, occurring in all of the injured rats. There were no correlate changes in heart rate observed in these rats. We then sought to examine the underlying causes of these blood pressure changes. Balance studies were performed using metabolic cages to examine salt and water intake and output before and during rTBI. Though intake of food and water were slightly affected by rTBI, no measurable effect of rTBI was observed on salt and water balance in these rats. We next measured cardiac function in anesthetized rats following rTBI and found no significant differences in any major contractile variables (LV systolic pressure, dP/tmax, dP/dtmin). In a final series of experiments, we evaluated renal blood flow during step-wise reductions in renal perfusion pressure using an aortic clamp and found that, while blood flow autoregulation was not impaired in rTBI rats, baseline renal blood flow was mildly reduced in injured rats compared to uninjured controls (3.44 ± 0.16 vs 3.94 ± 0.05 mL/min/gKW). In summary, we have generated a rat model of repeated traumatic brain injury that results in a consistent elevation of resting arterial blood pressure. Speculation that these observed changes may result from autonomic dysregulation remains to be investigated. University of Cincinnati College of Medicine Innovation Seed Grant This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Cystic Fibrosis-Related Diabetes Workshop: Research Priorities Spanning Disease Pathophysiology, Diagnosis, and Outcomes.

Cystic fibrosis (CF) is a recessive disorder arising from mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR) protein. CFTR is expressed in numerous tissues, with high expression in the airways, small and large intestine, pancreatic and hepatobiliary ducts, and male reproductive tract. CFTR loss in these tissues disrupts regulation of salt, bicarbonate, and water balance across their epithelia, resulting in a systemic disorder with progressive organ dysfunction and damage. Pancreatic exocrine damage ultimately manifests as pancreatic exocrine insufficiency that begins as early as infancy. Pancreatic remodeling accompanies this early damage, during which abnormal glucose tolerance can be observed in toddlers. With increasing age, however, insulin secretion defects progress such that CF-related diabetes (CFRD) occurs in 20% of teens and up to half of adults with CF. The relevance of CFRD is highlighted by its association with increased morbidity, mortality, and patient burden. While clinical research on CFRD has greatly assisted in the care of individuals with CFRD, key knowledge gaps on CFRD pathogenesis remain. Furthermore, the wide use of CFTR modulators to restore CFTR activity is changing the CFRD clinical landscape and the field's understanding of CFRD pathogenesis. For these reasons, the National Institute of Diabetes and Digestive and Kidney Diseases and the Cystic Fibrosis Foundation sponsored a CFRD Scientific Workshop, 23-25 June 2021, to define knowledge gaps and needed research areas. This article describes the findings from this workshop and plots a path for CFRD research that is needed over the next decade.

Histopathological spectrum of lesions of kidney: A morphological study

Introduction: The kidneys, as essential organs with diverse functions, are of paramount importance in the human body. Their primary role involves eliminating metabolic waste products and maintaining the balance of water, salt, calcium, phosphorus, anions, and cations to uphold the plasma's acid-base equilibrium. The objective of the current study is to investigate and understand the various morphological patterns exhibited by renal diseases, as well as assess their distribution across different age groups and genders. Material and Methods: The present study was conducted at Department of Pathology, Mamata Medical College, Khammam. A total of 32 nephrectomy specimens were studied.Results: The study shows, male to female ratio is 2.5:1 with male preponderance and among 32 nephrectomy specimens 20 were non-neoplastic and 12 were neoplastic. Neoplastic lesions constitute about 20 cases with chronic pyelonephritis being the most common cause (8 cases) leading to nephrectomy. Hydronephrosis (5 cases) majority of them showed enlarged kidneys with depressed scars and loss of corticomedullary differentiation. In the age group between 5th to 6th decades maximum number of non-neoplastic lesions was seen and least is observed in between 1st to 2nd decade. Conclusion: To conclude, these findings provide valuable insights into the histopathological patterns and distribution of kidney diseases in the studied population, contributing to our understanding of the prevalence and characteristics of these conditions.

Coupled water and salt balance models for Lake Urmia: Salt precipitation and dissolution effects

Investigating the dynamic evolution of storage volume and salinity of Lake Urmia (LU), which is crucial to present more reliable estimations of water balance components, needs to be furthur studied. We aimed to fill this gap by developing a coupled lumped mathematical model that considered the two-way effect of salt and water balance components on each other. Through the coupled water and salt balance model, salt precipitation and dissolution components were incorporated, and vaporation was calculated dynamically based on the lake’s salinity. The final model was then used as a tool to estimate the groundwater flux. Results indicated that during the lake shrinkage period (2009–2015), substantial salt precipitation with an average rate of 6.79 g/100 g/year (6.79 g of salt per 100 g water per year) occurred. In this period, the lake’s salinity increased to more than 450 g/l, and a negative trend of −0.200 km3/year in evaporation was detected. From 2016 to 2019, LU’s water level rose, and although great salt dissolution with an average rate of 4.27 g/100 g/year occurred, the lake’s salinity decreased. In 2019, with the least lake's salinity values (annual average of 266.1 g/l), the evaporation rate was 1.45 times greater than the average evaporation rate through the rest of the simulation period. While LU’s connection with groundwater resources varied temporally, the average groundwater flux (-0.203 km3/year) was higher than it could be neglected. Results of this study are expected to enhance the understanding of LU crisis and to improve the plan to prevent further shrinkage of the lake.

Progress of Euhalophyte Adaptation to Arid Areas to Remediate Salinized Soil

With the increasing shortage of water resources, the current management of saline–alkali lands in semi-arid and arid areas has gradually transformed from “flooding irrigation with drainage” in the past to the combination of controlling regional water and salt balance, phytoremediation, and comprehensive utilization of halophyte resources. However, soil salinization caused by natural and anthropogenic factors has still been a major global environmental problem, which changes the chemical and physical properties of soil, deteriorates the quality of underground water, and decreases biodiversity, contributing to the loss of soil productivity and the succession of the halotolerant species. Euhalophytes, as the materials for phytoremediation, have been confirmed to be effective species in improving saline–alkali soils. They can redistribute salts in soil profile through the interaction of their desalinization potential and irrigation water leaching, thereby preventing secondary salinization and improving soil productivity for long-term reclamation of saline soil. In this review, the adaptation mechanisms of euhalophytes to saline soils are generalized from the views of morphological, physiological, and molecular aspects and evaluated for their potential to remediate saline soil through salt removal and promoting leaching. Euhalophytes can not only sequestrate salts inside the central vacuole of cells to tolerate higher salt stress by means of organ succulence, ion compartmentalization, and osmotic adjustment but facilitate water infiltration and salts leaching through root–soil interaction. The root system’s mechanical penetration increases soil porosity, decreases soil density, as well as stabilizes soil aggregates. Moreover, the suitability of phytoremediation in arid situations with low precipitation and non-irrigation and some agricultural practices need to be taken into account to avoid salts returning to the soil as forms of litter and deep tillage altering salt distribution. Hence, euhalophytes planting in semi-arid and arid areas should be evaluated from their adaptation, desalinization, and prospective commercial values, such as foods, biofuels, and medical development to alleviate soil secondary salinization crisis and enhance the productivity of arable agricultural land.

A Simulation-Based Optimization Model for Control of Soil Salinization in the Hetao Irrigation District, Northwest China

The average annual water diversion of the Hetao Irrigation District (HID) from the Yellow River is 4.5 billion cubic meters, mainly used for surface irrigation. Because the groundwater depth is shallow, strong evaporation conditions and unmatched irrigation conditions lead to serious soil salinization in the area; thus, the irrigation area’s ecological environment is fragile. Based on the current situation of the Yellow River irrigation project in the area, an interval two-stage robust stochastic optimization model is proposed to address the problem. In 2015, the Shuguang Experimental Station in the middle of the HID, Inner Mongolia, discussed the impact of different degrees of water–salt coordinated regulation on water consumption, yield and price of wheat, maize and sunflower under drip irrigation conditions. The obtained results provide the water shortage and water distribution targets of multiple water sources and multiple water levels in five irrigation areas of the HID. Those water distribution targets were used as the main input parameter and entered into the SALTMOD model based on the principle of water and salt balance. The output included data on groundwater mineralization and groundwater depth. It was observed that (1) integrated interval two-stage robust stochastic programming and the SALTMOD Model to couple optimization model under uncertainty can simulate a model together; (2) systemic risk issues were considered; and (3) the proposed method can be applied to the HID in northwest China to solve the soil salinization control problem. This approach is applicable to arid and semiarid regions that face similar problems.

The role of the osmosensitive transcription factor NFAT5 in corneal edema resorption after injury

The osmosensitive transcription factor nuclear factor of activated T cells 5 (NFAT5; or tonicity-responsive enhancer binding protein; TonEBP) plays a key role in macrophage-driven regulation of cutaneous salt and water balance. In the immune-privileged and transparent cornea, disturbances in fluid balance and pathological edema result in corneal transparency loss, which is one of the main causes of blindness worldwide. The role of NFAT5 in the cornea has not yet been investigated. We analyzed the expression and function of NFAT5 in naive corneas and in an established mouse model of perforating corneal injury (PCI), which causes acute corneal edema and transparency loss. In uninjured corneas, NFAT5 was mainly expressed in corneal fibroblasts. In contrast, after PCI, NFAT5 expression was highly upregulated in recruited corneal macrophages. NFAT5 deficiency did not alter corneal thickness in steady state; however, loss of NFAT5 led to accelerated resorption of corneal edema after PCI. Mechanistically, we found that myeloid cell-derived NFAT5 is crucial for controlling corneal edema, as edema resorption after PCI was significantly enhanced in mice with conditional loss of NFAT5 in the myeloid cell lineage, presumably due to increased pinocytosis of corneal macrophages. Collectively, we uncovered a suppressive role for NFAT5 in corneal edema resorption, thereby identifying a novel therapeutic target to combat edema-induced corneal blindness.

Subsurface Anticyclonic Eddy Transited from Kuroshio Shedding Eddy in the Northern South China Sea

Abstract Subsurface eddies are a special type of oceanic eddy that display the maximum velocity in the subsurface layer. Based on field observations, a lens-shaped subsurface anticyclonic eddy (SAE) was detected in the northern South China Sea (SCS) in May 2021. The SAE was located between 20 and 200 m, with a shoaling of the seasonal thermocline and deepening of the main thermocline. Satellite images showed that the SAE exhibited positive sea level anomaly (SLA) and negative sea surface temperature (SST) anomaly. Eddy track indicated that this SAE originated from the Luzon Strait and was generated in the Kuroshio Loop Current (KLC) last winter. The evolution of the SAE was related to the anomalous water properties inside the eddy and the seasonal change of sea surface heat flux. In winter, the continuous surface cooling and Kuroshio intrusion led to a cold, salty core in the upper part of the anticyclonic eddy, which resulted in a subsurface-intensified structure through geostrophic adjustment. As the season changed from winter to spring, sea surface temperature increased. The lens-shaped structure was formed when the seasonal thermocline appeared near the surface that capped the winter well-mixed water inside the eddy. From 1993 to 2021, nearly half of the winter KLC shedding eddies (12/25) survived to late spring and evolved into subsurface lens-shaped structures. This result indicates that the transition of KLC shedding eddy to SAE is a common phenomenon in the northern SCS, which is potentially important for local air–sea interaction, heat–salt balance, and biogeochemical processes. Significance Statement Subsurface eddies are lens-shaped eddies with anomalous water properties in the subsurface layer. While such eddies have been reported in many regions of the World Ocean, they are poorly investigated in the SCS, especially the periodic subsurface eddies that appear in a fixed time frame with similar patterns and trajectories. This study reported a subsurface anticyclonic eddy (SAE) in the northern SCS and elucidated its generation and evolution processes. Statistical results confirm that this is a periodic SAE, which occurs nearly annually in late spring and evolves from the Kuroshio shedding eddy with seasonal changes. This study provides a new perspective on the evolution of subsurface eddies in the SCS and will benefit targeted observations in the future.

Heat-induced changes in blends of skimmed buffalo and bovine milk

This study investigated the physical, chemical, and structural changes in mixtures of buffalo and bovine milk (0:100, 25:75, 50:50, 75:25, 100:0) induced by heating at 80, 85, 90, and 95 °C for 5 min. No significant changes in particle size, zeta potential, and calcium activity were observed in heated buffalo milk and its mixtures with bovine milk, irrespective of the heating temperature, but heating at ≥ 85 °C induced a significant decrease in pH. The increase in viscosity with heating was dependent on the ratio of buffalo to bovine milk and the heating temperature. The variation in casein dissociation, whey proteins denaturation and their association with themselves and casein micelles, and the alteration in salt balance were key factors that contribute to significant heat-induced changes in pH and viscosity of milk blends.

Tidal Dispersion in Short Estuaries

AbstractThe salinity distribution of an estuary depends on the balance between the river outflow, which is seaward, and a dispersive salt flux, which is landward. The dispersive salt flux at a fixed cross‐section can be divided into shear dispersion, which is caused by spatial correlations of the cross‐sectionally varying velocity and salinity, and the tidal oscillatory salt flux, which results from the tidal correlation between the cross‐section averaged, tidally varying components of velocity and salinity. The theoretical moving plane analysis of Dronkers and van de Kreeke (1986) indicates that the oscillatory salt flux is exactly equal to the difference between the “local” shear dispersion at a fixed location and the shear dispersion which occurred elsewhere within a tidal excursion; therefore, they refer to the oscillatory salt flux as “nonlocal” dispersion. We apply their moving plane analysis to a numerical model of a short, tidally dominated estuary and provide the first quantitative confirmation of the theoretical result that the spatiotemporal variability of shear dispersion accounts for the oscillatory salt flux. Shear dispersion is localized in space and time due to the tidal variation of currents and the position of the along‐channel salinity distribution with respect to topographic features. We find that dispersion near the mouth contributes strongly to the salt balance, especially under strong river and tidal forcing. Additionally, while vertical shear dispersion produces the majority of dispersive salt flux during neap tide and high flow, lateral mechanisms provide the dominant mode of dispersion during spring tide and low flow.

Production of Drinking Water with Membranes with Simultaneous Utilization of Concentrate and Reject Effluent after Sludge Dewatering.

A new technology is described that enables us to completely exclude liquid discharges during production of drinking water from surface sources. The proposed described technological scheme separates the natural water into a stream of purified drinking water and dewatered sludge. The sludge moisture has a value of 80 percent. The experimental program is described to treat the natural water with nanofiltration membranes and to produce a drinking-quality water with recovery value of 0.99 and higher. Concentrate of membrane plant is mixed with the wet sludge and the reject effluent after sludge dewatering is again treated by reverse osmosis membranes and returned back to the sludge thickening tank. Results of experiments to treat reject water after sludge dewatering are presented. The use of nanofiltration membranes provides reduction in the Total Dissolved Solids content (TDS), aluminum, color and oxidation to meet drinking water standards. Experimental plots are presented that can be used to select membrane characteristics and to predict product water chemical composition at each stage of the membrane treatment scheme. Concentrate of membrane treatment plant is mixed with the wet sludge in the thickening tank. The sludge, after the thickening tank, is dewatered using either filter-press or centrifugal equipment. The reject (or fugate), after sludge dewatering, is treated by membrane facility to separate it into deionized water stream and concentrate stream. The deionized water can be mixed with the feed water or drinking water and the concentrate stream is returned back to the thickening tank. Thus, the salt balance is maintained in the thickening tank, whereby all dissolved salts and impurities that are rejected by membranes are collected in the thickening tank, and then are withdrawn together with the dewatered sludge. Based on the results of experimental data processing, balance diagrams of the sludge dehydration process with waste water purification at the membrane plant and with the addition of the membrane plant concentrate to the sludge thickener are presented, according to which all contaminants removed by the membranes are removed together with the sludge.

Simulation of Soil Water and Salt Balance in Three Water-Saving Irrigation Technologies with HYDRUS-2D

Mulch drip irrigation (MDI) technology can effectively solve the problem of insufficient temperature accumulation during the pre-fertility period and facilitate the efficient supplementation of water and fertilizer during the fertility period in spring corn planting. Moreover, this local MDI technology also has impacts on the farmland environment. To investigate the effect of drip irrigation technology on the water and salt environment of farmland, a field study on corn cultivation was carried out at West Liaohe Plain. In addition, the water and salt dynamics of the farmland were simulated using HYDRUS-2D for mulch drip irrigation (MDI), shallowly buried drip irrigation (SBDI), and sprinkler irrigation (SI), with variable rainfall and initial salt content. The results showed that the distribution of and variation in water and salt in the soil were similar under MDI and SBDI. The change near the drip tape was mainly affected by irrigation, while the water and salt in the soil between drip tapes were correlated with irrigation and rainfall. The amount of salt in the topsoil (5 cm) increased with a decrease in rainfall. With an initial EC = 480 μs/cm (soil salt content 0.1%), the salinity of the topsoil under MDI was significantly higher than that under SBDI and SI within two years. The topsoil salinity was similar for all three irrigation technologies with increasing operating life, reaching a relatively stable state, and much lower than the salinity determination threshold of 480 μs/cm. Given the current conditions of rainfall, soil, buried depth, and mineralization in the West Liaohe Plain, the risk of secondary salinization is minimal if irrigation management is reasonable. This study provides data to support the application of drip irrigation technology in the Western Liaohe Plain.