Salt Absorption Research Articles

Late rise in hemolymph osmolality in Macrobrachium acanthurus (diadromous freshwater shrimp) exposed to brackish water: Early reduction in branchial Na+/K+ pump activity but stable muscle HSP70 expression.

Some Macrobrachium shrimps (Caridea, Palaemonidae) are diadromous; freshwater adults are truly euryhaline, while larvae need saline water for development. Branchial Na+/K+-ATPase (NKA) and carbonic anhydrase (CA) are involved in NaCl absorption in freshwater. This study aimed at verifying the time course of the osmoregulatory response of adult Macrobrachium acanthurus to high salinity brackish water (20‰), from the first 30min to 5days. The goal was to detect possible transition from hyper- to hyporegulation, the putative involvement of branchial NKA and CA, or the induction of muscular HSP70 expression. Hemolymph osmotic and ionic concentrations remained relatively stable and close to control levels until ~9h of exposure, but later increased consistently (~50%). A fast reduction in NKA activity (3-6h) was observed; these shrimps seem to shut off salt absorption already in the first hours. Later on, especially after 24h, hemolymph concentrations rise but HSP70 expression is not induced, possibly because constitutive levels are already sufficient to prevent protein damage. Time-dependent response mechanisms effective in high salinity brackish water, resulting in salt loading avoidance and suggestive of hyporegulation should be further investigated in decapods that evolutionary invaded freshwater.

Urinary concentrations and antimicrobial activity of tobramycin in healthy volunteers receiving a single oral dose of a novel formulation for improved absorption

Oral antibiotics for the treatment of urinary tract infections are scarce. In this ex vivo phase 1 annex study, the clinical safety, urinary concentrations and bactericidal activity of a new formulation for improved oral absorption of tobramycin (Tobrate™) were evaluated. Minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of five test strains, one reference strain and four clinical uropathogenic strains were determined in cation-adjusted Mueller–Hinton broth (CA-MHB) and in pooled antimicrobial agent-free subjects' urine at different pH values (5.5, 6.5, 7.5 and 8.5). Urinary concentrations and urinary bactericidal titres (UBTs) following single oral administration of 600 mg Tobrate™ were measured in nine healthy volunteers up to 24 h. The MIC/MBC values in CA-MHB were 2–4/2–4 mg/L for two Escherichia coli strains, 2/2 mg/L for Klebsiella pneumoniae, 0.5/1 mg/L for Pseudomonas aeruginosa and 8/1 mg/L for Proteus mirabilis. MBCs in pooled alkaline urine were significantly lower than those in acidic urine. The mean maximum urinary concentration following 600 mg tobramycin was 83.9 mg/L (2–4 h collection period). The highest reciprocal median UBT values for each test strain were between 2 and 4 during the collection periods 2–4 h and 4–8 h, respectively. The new enteric oral tobramycin formulation significantly improved the very poor oral absorption of standard tobramycin salt. For all pathogens tested, maximum urinary concentrations of tobramycin were at least two times above the urinary MBC. A twice- or three-times daily dosage regimen and alkalising co-medication may further improve urinary bactericidal activity.

Molecular Engineering of UV/Vis Light-Emitting Diode (LED)-Sensitive Donor-π-Acceptor-Type Sulfonium Salt Photoacid Generators: Design, Synthesis, and Study of Photochemical and Photophysical Properties.

A series of donor-π-acceptor-type sulfonium salt photoacid generators (PAGs) were designed and synthesized by systematically changing electron-donating groups, π-conjugated systems, electron-withdrawing groups, and the number of branches through molecular engineering. These PAGs can effectively decompose under UV/Vis irradiation from a light-emitting diode (LED) light source because of the matching absorption and emitting spectra of the LEDs. The absorption and acid-generation properties of these sulfonium salts were elucidated by UV/Vis spectroscopy and so forth. Results indicated that the PAG performance benefited from the introduction of strong electron-donating groups, specific π-conjugated structures, certain electron-withdrawing groups, or two-branched structures. Most sulfonium salts showed potential as photoinitiators under irradiation by a wide variety of UV and visible LEDs.

Differential expression of putative sodium-dependent cation-chloride cotransporters in Aedes aegypti

The yellow fever mosquito, Aedes aegypti, has three genes that code for proteins with sequence similarity to vertebrate Na+-K+-Cl− cotransporters (NKCCs) of the solute-linked carrier 12 superfamily of cation-chloride cotransporters (CCCs). We hypothesized that these mosquito NKCC orthologues have diverged to perform distinct roles in salt secretion and absorption. In phylogenetic analyses, one protein (aeNKCC1) groups with a Drosophila melanogaster NKCC that mediates salt secretion whereas two others (aeCCC2 and aeCCC3) group with a Drosophila transporter that is not functionally characterized. The aeCCC2 and aeCCC3 genes probably result from a tandem gene duplication in the mosquito lineage; they have similar exon structures and are consecutive in genomic DNA. Predicted aeCCC2 and aeCCC3 proteins differ from aeNKCC1 and vertebrate NKCCs in residues from the third transmembrane domain known to influence ion and inhibitor binding. Quantitative PCR revealed that aeNKCC1 and aeCCC2 were approximately equally expressed in larvae and adults, whereas aeCCC3 was approximately 100-fold more abundant in larvae than in adults. In larval tissues, aeCCC2 was approximately 2-fold more abundant in Malpighian tubules compared to anal papillae. In contrast, aeCCC3 was nearly 100-fold more abundant in larval anal papillae compared to Malpighian tubules, suggesting a role in absorption. Western blots with polyclonal antibodies against isoform-specific peptides revealed stronger aeCCC2 immunoreactivity in adults versus larvae, whereas aeCCC3 immunoreactivity was stronger in larvae versus adults. The differential expression pattern of aeCCC2 and aeCCC3, and their sequence divergence in transmembrane domains, suggests that they may have different roles in transepithelial salt transport.

塩の影響を考慮した布における熱・水分同時移動 : 第1報-塩溶液の浸透実験と塩の影響を考慮した布の平衡含水率

塩の影響を考慮した布における熱・水分同時移動 : 第1報-塩溶液の浸透実験と塩の影響を考慮した布の平衡含水率

Corrosion Behavior of Carbon Steel Under Environment Simulated inside of Concrete Containing Chloride Ion

Many infrastructures such as expressways and buildings were constructed in Japan between the 1950s and the 1970s. There is greatly influence of airborne sea salt on corrosion in Japan surrounded by the sea, and reinforcement corrosion is accelerated by rainfall, dew condensation and water absorption of airborne sea salt. Therefore, many of these infrastructures are in a condition requiring repair or renewal in the present. In this study, electrochemical measurements of carbon steel were conducted in an aqueous solution simulated the inside of concrete, in order to investigate corrosion behavior of reinforcing bars in concrete. In addition, the influence of surface condition of the reinforcing bars before corrosion on their corrosion resistance was examined by the corrosion monitoring using an electrochemical impedance method. Carbon steel and 0.1% Ca(OH)2 solution were used as the sample for the reinforcing bar in concrete and as the test solution simulating the internal environment of the concrete, respectively. The corrosion resistance of passive film in concrete was investigated by anodic polarization measurement and electrochemical impedance measurement. The passive film region was observed regardless of concentration of chloride ion in the test solution. The current density in the test solution containing 0M and 0.01M of chloride ion did not abruptly increase in the passive state region and local corrosion such as pitting corrosion did not occur on the steel surface. A sharp rise in current density was observed in the test solution containing 0.1M or more of chloride ion. The anodic polarization curves of carbon steel with passive film formed by immersion in the test solution was measured, in order to investigate the influence of the film formation period on the properties of passive film. A passive region was observed in the anodic polarization curves of all samples. The passive current density decreased with an increase of immersion time, indicating that the corrosion resistance of the passive film improved as the immersion time increased. Furthermore, the electrochemical impedance measurements of carbon steel passivated in the test solution were carried out. The impedance characteristic can be represented by a typical Randles type equivalent circuit, and the diameter of the semicircle corresponds to the film resistance. The film resistance increased in proportion to the immersion time in the test solution. This result is consistent with the result of the anodic polarization measurement.

Electrical potential induced switchable wettability of super-aligned carbon nanotube films

Controlling of the wettability of micro-nano scale surfaces not only plays important roles in basic science but also presents some significant applications in interference shielding materials, microfluidics and phase-change heat transfer enhancement, etc. Here, the superhydrophobic super-aligned carbon nanotube (SACNT) films are firstly obtained by the chemical vapor deposition method and the annealing process. Then their wettabilities are in-situ switched by the electrowetting strategy. Specifically, the fascinating transformation of superhydrophobicity to the superhydrophilicity is achieved by exerting external DC voltages across the CNT-liquid interfaces, and the transitions of Cassie-to-Wenzel states are observed on the multilayer SACNT films. In addition, the electrowetting induced salt absorption of the porous SACNT is also reported here. Finally, the threshold voltages of the electrowetting behaviors for different liquids on the SACNT films and unit capacitances across the CNT-liquid interfaces are obtained, which reveal that the SACNT films have much more outstanding electrowetting properties than the previously reported works. Our approach reported here demonstrates that the wettability of SACNT films could be simply, effectively and in-situ controlled by the electrowetting method, which will have many profound implications in numerous applications such as phase-change heat transfer enhancement, optical lens with variable focal length and microfluidics, etc.

KCNE1 and KCNE3 modulate KCNQ1 channels by affecting different gating transitions

KCNE β-subunits assemble with and modulate the properties of voltage-gated K+ channels. In the heart, KCNE1 associates with the α-subunit KCNQ1 to generate the slowly activating, voltage-dependent potassium current (IKs) in the heart that controls the repolarization phase of cardiac action potentials. By contrast, in epithelial cells from the colon, stomach, and kidney, KCNE3 coassembles with KCNQ1 to form K+ channels that are voltage-independent K+ channels in the physiological voltage range and important for controlling water and salt secretion and absorption. How KCNE1 and KCNE3 subunits modify KCNQ1 channel gating so differently is largely unknown. Here, we use voltage clamp fluorometry to determine how KCNE1 and KCNE3 affect the voltage sensor and the gate of KCNQ1. By separating S4 movement and gate opening by mutations or phosphatidylinositol 4,5-bisphosphate depletion, we show that KCNE1 affects both the S4 movement and the gate, whereas KCNE3 affects the S4 movement and only affects the gate in KCNQ1 if an intact S4-to-gate coupling is present. Further, we show that a triple mutation in the middle of the transmembrane (TM) segment of KCNE3 introduces KCNE1-like effects on the second S4 movement and the gate. In addition, we show that differences in two residues at the external end of the KCNE TM segments underlie differences in the effects of the different KCNEs on the first S4 movement and the voltage sensor-to-gate coupling.

Crude Oil Desalting by Using Nanocarbon

In the process of crude oil desalination, the aim is to separate dispersed phase of brine from oil phase. The project aim is the use of carbon nano-adsorbent for remov-al of salt from crude oil that, unlike other methods of salt separation from crude oil currently used, is a simple, inexpensive method with good ability to remove salt from crude oil. In this study, first, four types of carbon adsorbent were used for removal of salt from crude oil using dispersion in solution method. Then, the adsorbents that had the best absorption were identified. In continuation, two nano-adsorbents were selected from nano-adsorbents and their effect on the absorption of salt from crude oil was investigated using filtration method. Finally, a survey was carried out on regeneration of multi-walled carbon nanotubes that had the ability to absorb more than 50% of salt from crude oil, which were then selected as the best nano-adsorbents.

(Invited) An Aqueous Rechargeable Desalination System

In this work, we present a new concept of aquous flow battery deionization (FBDI) system based on dual-ions electrochemistry, which consists of BiOCl as chloride-capture anode, sodium manganese oxide (Na0.44MnO2) as sodium-capture cathode. It utilizes a redox reaction to individually absorb chloride ion at anode and sodium ion at cathode at the same time. When charged, the two ions are released to flow sodium chloride electrolyte solution. Upon discharge, the chloride ion was extracted into the anode from flow NaCl solution while sodium ion was electrochemically captured into the cathode. The novel battery deionization delivers a stable and reversible salt absorption/desorption capacity of 68.5 mg g-1 with ~100% columbic efficiency when operated at a current density 100 mA g-1, which makes over twice salt absorption of the previous reported best performance (31.2 mg g-1) obtained by a hybrid capacitive deionization system. The “ion/electron transfer efficiency” as a new concept was proposed to replace the “charge efficiency”, since the salt was removed during the discharge process, which is the first time to report thus a phenomenon. The ion/electron transfer efficiency is up to 0.977 during charge-desorption process and 0.958 during discharge-absorption process. Owing to salt removal during discharge, the current system is called “desalination generator”. The current study will supply a new view of desalination and flow battery system.

Histological alterations in gills of Macrobrachium amazonicum juveniles exposed to ammonia and nitrite

Aquaculture has shown great growth in the last decades. Due to the restrictions on water use, production systems are becoming increasingly more intensive, raising concerns about the production water quality. Macrobrachium amazonicum is among the freshwater prawn species with favorable characteristics for production and possibility of intensification. Nitrogen compounds such as ammonia and nitrite affect the health of aquatic organisms since they quickly reach toxic concentrations. These compounds can also cause damage to the gill structure, leading to hypoxia in tissues, affecting acid-base balance, osmoregulation (salt absorption) and ammonia excretion, decreasing the immune capacity of the animal and, in extreme cases, cause death. The aim of this study was to assess histological changes in the gills of Macrobrachium amazonicum juveniles subjected to different concentrations of total ammonia and nitrite. The prawns were subjected to different concentrations of those compounds and their gills were removed and preserved for histological analysis. The gills were assessed for changes according to the Organ Index (Iorg) and, for each change, an importance factor (w) was attributed according to the degree of reversibility and applied according to the degree of extension or frequency of the damage. The damage to the gills in the treatments with 100% mortality, both for ammonia and nitrite, corresponded to the high occurrence of progressive, regressive, circulatory, and inflammation damages. The other treatments (which caused less mortality) had mainly inflammation and regressive damages, whose occurrence increased according to the increase in ammonia and nitrite concentration. The histological analysis confirmed that the higher the total ammonia and nitrite concentrations, the larger the damages caused to the gill structure and that lower nitrite concentrations caused similar damages to those caused by higher total ammonia concentrations, which reflects the lower capacity M. amazonicum has to tolerate nitrite.

Expression of Sodium‐Dependent Cation‐Chloride Cotransporters in Adult and Larval Osmoregulatory Tissues of Aedes aegypti Mosquitoes

Yellow fever mosquitoes, Aedes aegypti, face diverse salt and water challenges. Larvae lose salt to the freshwater environment and gain water osmotically, whereas adults tend to lose water by evaporation. Moreover, adult females take in large quantities of salt and water during a blood meal. We hypothesize that sodium‐dependent cation‐chloride cotransporters (CCCs) contribute to the salt and water balance of Aedes aegypti by participating in epithelial salt secretion and absorption. Sequence analysis revealed three genes (AAEL006180, AAEL009888, and AAEL009886) in Aedes aegypti with similarity to vertebrate Na‐K‐Cl cotransporters. We performed multiple sequence alignment and phylogenetic analysis of the proteins encoded by the Aedes aegypti genes and orthologs in Culex and Anopheles mosquitoes, Drosophila, and other arthropods. The protein encoded by AAEL006180 groups in a clade with the human secretory Na‐K‐Cl cotransporter and a Drosophila cotransporter known to be involved in salt secretion. In contrast, AAEL009888 and AAEL009886 fall into a clade that includes sequences from other insects but not vertebrates. Moreover, both AAEL009888 and AAEL009886 have orthologs in other mosquito genera but other insects only have one ortholog, indicating that AAEL009888 and AAEL009886 probably diverged early in the evolution of mosquitoes. Amino acids that differ among the paralogs include residues known to influence ion and inhibitor binding affinities. Using qPCR, we quantified the relative gene expression of the Aedes aegypti paralogs with at least two isoform‐specific primer sets for each gene. AAEL009886 transcript is expressed at significantly greater levels in larvae compared to adults and at significantly greater levels in anal papillae compared to Malpighian tubules, suggesting that AAEL009886 may be specialized for ion absorption in larvae. In contrast, AAEL006180 and AAEL009888 transcripts are expressed at approximately the same levels in adults and larvae. To evaluate the physiological role of the proteins encoded by AAEL006180 and AAEL009888, we attempted to reduce expression of each transporter using dsRNA. Larvae exposed to dsRNA corresponding to either transporter had up to five‐fold increases in hemolymph ammonium levels compared to negative controls as well as smaller changes in other hemolymph cations. Our results point towards physiological roles for AAEL006180 and AAEL009888 in osmoregulation and ammonia balance of larval mosquitoes.Support or Funding InformationNSF‐IOS‐1557230

Theoretical structural characterization of lymphoguanylin: A potential candidate for the development of drugs to treat gastrointestinal disorders

Guanylin peptides (GPs) are small cysteine-rich peptide hormones involved in salt absorption, regulation of fluids and electrolyte homeostasis. This family presents four members: guanylin (GN), uroguanylin (UGN), lymphoguanylin (LGN) and renoguanylin (RGN). GPs have been used as templates for the development of drugs for the treatment of gastrointestinal disorders. Currently, LGN is the only GP with only one disulfide bridge, making it a remarkable member of this family and a potential drug template; however, there is no structural information about this peptide. In fact, LGN is predicted to be highly disordered and flexible, making it difficult to obtain structural information using in vitro methods. Therefore, this study applied a series of 1μs molecular dynamics simulations in order to understand the structural behavior of LGN, comparing it to the C115Y variant of GN, which shows the same Cys to Tyr modification. LGN showed to be more flexible than GN C115Y. While the negatively charged N-terminal, despite its repellent behavior, seems to be involved mainly in pH-dependent activity, the hydrophobic core showed to be the determinant factor in LGN's flexibility, which could be essential in its activity. These findings may be determinant in the development of new medicines to help in the treatment of gastrointestinal disorders. Moreover, our investigation of LGN structure clarified some issues in the structure-activity relationship of this peptide, providing new knowledge of guanylin peptides and clarifying the differences between GN C115Y and LGN.

Efficient and Reversible Absorption of Sulfur Dioxide of Flue Gas by Environmentally Benign and Stable Quaternary Ammonium Inner Salts in Aqueous Solutions

Novel kinds of environmentally benign and stable absorbents, quaternary ammonium inner salts betaine (Bet) and l-carnitine (l-car) in aqueous solution, were designed and applied to efficiently and reversibly capture sulfur dioxide (SO2) in flue gas. The effects of the inner salt concentration, absorption temperature, SO2 concentration, and reuse cycle on the absorption of SO2 by the two absorbents were investigated. The results show that SO2 absorption capacities of the absorbents with 50% inner salt mass fraction were 0.155 mol of SO2/mol of Bet for Bet aqueous solutions and 0.599 mol of SO2/mol of l-car for l-car aqueous solutions, at 40 °C with a SO2 concentration of 2%, and the absorption capacities of absorbents did not change after 5 absorption/desorption cycles. Furthermore, Fourier transform infrared spectroscopy and proton nuclear magnetic resonance results demonstrate that the SO2 absorption follows the law that a strong acid (H2SO3) replaces a weak acid (−COOH). The absorbents could be used for...

Alternate Dough Preparation Protocol for Extensigraph Test of Dough Strength

The extensigraph is an internationally accepted method for measurement of physical properties of dough subjected to mechanical handling and resting. Standard extensigraph methods (AACC International Approved Method 54‐10.01, ISO 5530‐2) use the farinograph for the preparation of dough in the presence of 2% salt at reduced water absorption (farinograph absorption minus 2–3%). However, the dough so prepared is usually underdeveloped and drier than typically seen in common baking processes. In addition, the standard extensigraph test is time consuming and requires a large sample size. In this study, an alternate dough preparation protocol is proposed, consisting of a Swanson‐type pin mixer at reduced salt (1%) and elevated water absorption (farinograph absorption plus 4%). With the alternate method, dough is fully developed and similar to bread dough in physical properties. AACCI Approved Method 54‐10.01 is followed for dough rounding, molding, resting, and stretching by using the Brabender Extensograph‐E instrument. Strong correlations for resistance to extension (r = 0.90) and area (r = 0.92) were found between the modified and standard dough preparation methods. This protocol requires much less flour sample and significantly increases sample throughput.

Spectroscopic ellipsometry characterization of spin-coated Ge25S75 chalcogenide thin films

Abstract Spectroscopic ellipsometry study on spin-coated non-toxic Ge25S75 thin films annealed at different temperatures were conducted. Multi sample analysis with two sets of samples spin-coated onto soda-lime glass and onto silicon wafers was utilized. Optical constants (refractive index n and extinction coefficient k) of these films were determined from ellipsometric data recorded over a wide spectral range (0.05–6 eV). Different parametrization of Ge25S75 complex dielectric permittivity which consists of a Tauc-Lorentz or Cody-Lorentz oscillator describing the short wavelength absorption edge, a Lorentz or Gauss oscillators describing phonon absorption or optically active absorption of alkyl ammonium germanium salts in the middle infrared part of spectra is discussed. Using a Mott-Davis model, the decrease in local disorder with increasing annealing temperature is quantified from the short wavelength absorption edge onset. Using the Wemple-DiDomenico single oscillator model for the transparent part of the optical constants spectra, a decrease in the centroid distance of the valence and conduction bands with increasing annealing temperature is shown and increase in intensity of the inter-band optical transition due to annealing temperature occurs. Intensity of absorption near 3000 cm−1 could be used as alternative method to evaluation of quality of prepared films.

Effects of counter anions, P-substituents, and solvents on optical and photophysical properties of 2-phenylbenzo[b]phospholium salts.

In this work, we investigated the effects of counter anions, P-substituents, and solvents on the optical and photophysical properties of 2-phenylbenzo[b]phospholium salts in solution. A series of 2-phenylbenzo[b]phospholium salts was prepared by P-alkylation or P-phenylation of 1,2-diphenylbenzo[b]phosphole followed by anion exchange reactions. X-ray crystallographic analyses of six benzo[b]phospholium salts showed that each phosphorus center has an onium nature with an essentially tetrahedral geometry. 1H NMR and steady-state UV-vis absorption and fluorescence spectroscopic measurements of these phospholium salts revealed the pivotal role of counter-anion solvation. The observed results are discussed on the basis of the association-dissociation equilibrium between a contact ion pair (CIP) and a solvent-separated ion pair (SSIP) in solution. The hexafluorophosphates exist as SSIPs and emit intense fluorescence, irrespective of the P-substituents and solvents. In contrast, the iodides are present as SSIPs in methanol but exist as equilibrium mixtures of the two emitting species, SSIP and CIP, in dichloromethane. As a consequence, fluorescence intensities of the iodides varied significantly depending on the solvents, P-substituents, and solution concentrations. These findings were studied in more detail using time-resolved fluorescence spectroscopy and fluorescence titration measurements. The light-emitting properties of the 2-phenylbenzo[b]phospholium halides in the CIPs rely on heavy atom effects derived from the counter halide anions on the S1 state of the adjacent cationic benzo[b]phosphole π-systems. The present study suggests that 2-arylbenzo[b]phospholium salts would be promising scaffolds for developing new phosphole-based ionic fluorophores that are capable of responding to external stimuli such as anionic species and solvents.

The influence of molecular weights on the calcium salts absorption of polyacrylic based materials

Most of the industries use water as medium for heating, cooling and also washing of the equipment and facing problems caused by hard water which consist of carbonate and sulfate salts which remain on the walls of reactors and pipes. For this reason, different water softeners are used, with ability to absorb metallic ions and prevent agglomeration of salts on surfaces. Polymeric materials, especially polycarboxylates, can be used to prevent this problem. In this work the influence of molecular weight and molecular composition of poly(acrylic acid-co-maleic acid) carboxylate copolymer on the calcium salts absorption was investigated. Copolymers were prepared by radical polymerization in water-borne system using potassium persulfate as initiator and iron ions (Fe2+) as chain length regulator. Molecular structures of obtained polymers were analyzed by FTIR method, and confirmed copolymer structure of resulted polymers. Average molecular weights and degree of polydispersity were determined by GPC. From the results of molecular weights determination it can be concluded that increasing of Fe2+ content leads to decreasing of the molecular weights of copolymers. Presence of ordered structures was confirmed using X-ray diffraction method (XRD). Dispersing capacity results of obtained copolymers have showed that with decreasing of molecular weights of copolymers calcium carbonate dispersing capacity (CCDC) decreased.

Ablation of the Cl-/HCO3- Exchanger Pendrin Enhances Hydrochlorothiazide-Induced Diuresis

Background/Aims: The Cl^-/HCO₃^- exchanger pendrin and the thiazide-sensitive Na-Cl cotransporter NCC are expressed in the kidney distal nephron and mediate salt absorption. We hypothesized that deletion of pendrin leaves NCC as the major salt absorbing transporter in the distal nephron and therefore enhances salt excretion by hydrochlorothiazide (HCTZ). Methods: Metabolic cage studies were performed in wild type, pendrin KO and NCC KO mice at baseline and following HCTZ treatment. In parallel studies, systemic blood pressure was measured in mice treated with HCTZ with the tail cuff method. Results: Urine output, salt excretion and water intake were comparable in all groups under baseline condition. Urine output and water intake increased significantly only in pendrin KO mice in response to HCTZ, but not in WT or NCC KO mice. Sodium and chloride excretion increased in HCTZ-treated pendrin KO mice, but they remained unchanged in WT or NCC KO mice. Pendrin KO mice treated with HCTZ developed volume depletion, as determined by increased expression of renin mRNA and protein. The expression of ENaC and pendrin increased in HCTZ-treated WT mice. HCTZ treatment did not significantly modify blood pressure in any of the experimental group. Conclusion: The ablation of the Cl^-/HCO₃^- exchanger Pendrin enhances the magnitude of salt wasting by HCTZ.

Radiation Heat Transfer in the Molten Salt FLiNaK

The molten fluoride salt eutectic LiF-NaF-KF (FLiNaK) has been proposed as a coolant for use in Generation IV reactors designed to operate at temperatures at which radiation heat transfer (RHT) may be significant. Little research has been performed into the absorption coefficient of FLiNaK as it pertains to thermal RHT. An estimate of the spectral absorption coefficient for FLiNaK has been generated using informed assumptions and existing data for the constituent salts. The effect of heat transfer, as it pertains to flowing salt in circular cross-section pipes with heated walls, has been investigated for laminar flow using a mathematical model. The combined energy equation, in various geometries, was solved for laminar flow, with the radiative heat flux calculated using the differential approximation. The percentage of energy transferred by radiation to the salt was found to be primarily a function of pipe diameter, wall temperature, and the salt absorption coefficient. A map of temperatures and pipe diameters has been generated, which indicates where RHT is significant. A correlation has been proposed, based on the mathematical model, to account for increase in Nusselt number due to radiation. Additional discussion is included on the effects of wall emissivity and high Reynolds flows.