Loss Of Chloride Research Articles

Chemical and photochemical properties of a ruthenium nitrosyl complex with the N-monosubstituted cyclam 1-(3-Propylammonium)-1,4,8,11-tetraazacyclotetradecane

The amine-functionalized trans-[Ru(NO)Cl(1-pramcyH)](PF6)3 complex (1-pramcyH = 1-(3-propylammonium)-1,4,8,11-tetraazacyclotetradecane) was synthesized from trans-[RuCl(tfms) (1-pramcyH)](tfms)2 (tfms = trifluoromethanesulfonate) in acidic aqueous solution in the presence of nitric oxide (NO). The complex was characterized by elemental, spectroscopic (UV-Vis, IR, ¹H and 13C NMR) and electrochemical analyses. Two pKa values (7.0 and 8.2) were estimated for trans-[Ru(NO)Cl(1-pramcyH)](PF6)3 and were assigned to one of the cyclam nitrogen protons and to the protonated aminopropyl group. Reduction of trans-[Ru(NO)Cl(1-pramcyH)]3+ results in rapid loss of chloride followed by slower loss of NO, while irradiation of the complex in aqueous deaerated conditions suggests photochemical labilization of NO. The quantum yields for NO photoaquation decrease as the irradiation wavelength increases, being noticeable only at λirr < 370 nm, and increase as pH increases. The behavior of trans-[Ru(NO)Cl(1-pramcyH)]3+, which contains an aminopropyl substituted cyclam, parallels that reported for the analogous complex with the unsubstituted ligand, but differs from that described for the complex in which carboxypropyl is the substituent.

Striking Differences between the Solution and Solid-State Reactivity of Iron PNP Pincer Complexes with Carbon Monoxide

Several new iron(II) complexes of the types [Fe(PNP)X2] (X = Cl, Br) containing tridentate PNP pincer-type ligands based on 2,6-diaminopyridine and 2,6-diaminopyrimidine have been prepared. They all exhibit intermolecular Fe−X···H−N hydrogen bonds, forming supramolecular networks in the solid state. In the case of X = Cl these compounds react readily with gaseous CO both in the solid state and in solution to give selectively the octahedral complexes cis- and trans-[Fe(PNP)(CO)(Cl)2], respectively, whereas with X = Br mixtures of cis and trans isomers are obtained. These transformations are accompanied by color and spin-state changes. CO binding is fully reversible in all cases, and heating solid samples of either cis- or trans-[Fe(PNP)(CO)(X)2] leads to complete regeneration of analytically pure [Fe(PNP)(X)2]. Mössbauer spectroscopy confirmed the high-spin nature of the parent five-coordinate Fe(II) complex (δ = 0.80(1) mm s−1) and the shift to two different low-spin octahedral species after reaction with CO in the solid (δ = 0.13(1) mm s−1) or in solution (δ = 0.15(1) mm s−1). Magnetization studies led to a magnetic moment close to 4.9 μB, reflecting the expected four unpaired d-electrons in [Fe(PNP)Cl2], which were confirmed by DFT calculations. The DFT study of the reaction pathway for CO capture led to low energy barriers (≤3.4 kcal mol−1). The cis−trans isomerization reaction was found to take place with a low energy barrier (10.8 kcal mol−1), after initial loss of chloride, and involves also spin-state changes

Impact of normal saline infusion on postoperative metabolic acidosis

Standard base excess (SBE) is an important parameter for guiding fluid management in postoperative metabolic acidosis. However, individual SBE components, notably the chloride effect (Cl(eff)), provide valuable additional information. Cl(eff) is the deviation of the strong ion difference (SID) from normal caused by chloride loss or increase and represents the effect on SBE of an abnormal chloride-sodium ratio. Many centers use normal saline (NS) for intravascular volume therapy. In this study, we examined the impact of NS infusion on SBE and its chloride-driven component (Cl(eff)) in postoperative children. The study was conducted in 119 children who underwent post-heart surgery in a Swiss pediatric intensive care unit. The 72-h postoperative course was divided into six observation periods, during which NS input and its impact on SBE and Cl(eff) were measured per period in each patient, and the results compared between patients infused and not infused with NS during each period. Normal saline was infused in 168/625 observation periods if indicated by volume deficit. Postoperative metabolic acidosis and the acidifying Cl(eff) were aggravated in the first 12 postoperative hours. Over the 72 h, NS infusion simultaneously lowered SBE by -0.06 mm x ml(-1) x kg(-1) body weight infused and Cl(eff) by -0.07 mm. Implementing serial Cl(eff) assessment could improve postoperative management by disclosing or excluding hyperchloremia as a cause of acidosis undetectable from SBE alone. Calculating the chloride-driven acidifying side effect of NS infusion using Cl(eff) improves the interpretation of SBE values and can optimize fluid management in postoperative metabolic acidosis.

Gitelman Syndrome

Gitelman Syndrome

Synthesis of dimethyl carbonate (DMC) from methanol and CO2 over Rh-supported catalysts

Abstract The synthesis of dimethyl carbonate (DMC) from methanol and CO 2 has been investigated using a vapor phase flow reactor system and in the presence of various Rh-supported catalysts. The effects of reaction conditions, supports, and promoters on catalyst performance were evaluated in terms of methanol conversion and DMC selectivity. The results show that DMC synthesis proceeds effectively at low temperatures (353–433 K), while at higher temperatures dimethyl ether (DME) is the predominant product. Loss of surface chloride results in substantial catalyst system deactivation.

Impacts of episodic acidification on in-stream survival and physiological impairment of Atlantic salmon (Salmo salar) smolts

We conducted field studies to determine the levels of acid and aluminum (Al) that affect survival, smolt development, ion homeostasis, and stress in Atlantic salmon ( Salmo salar ) smolts in restoration streams of the Connecticut River in southern Vermont, USA. Fish were held in cages in five streams encompassing a wide range of acid and Al levels for two 6-day intervals during the peak of smolt development in late April and early May. Physiological parameters were unchanged from initial sampling at the hatchery and the high water quality reference site (pH &gt; 7.0, inorganic Al &lt; 12 μg·L–1). Mortality, substantial loss of plasma chloride, and gill Na+/K+-ATPase activity, and elevated gill Al occurred at sites with the lowest pH (5.4–5.6) and highest inorganic Al (50–80 μg·L–1). Moderate loss of plasma chloride, increased plasma cortisol and glucose, and moderately elevated gill Al occurred at less severely impacted sites. Gill Al was a better predictor of integrated physiological impacts than water chemistry alone. The results indicate that Al and low pH under field conditions in some New England streams can cause mortality and impair smolt development in juvenile Atlantic salmon and provide direct evidence that episodic acidification is impacting conservation and recovery of Atlantic salmon in the northeastern USA.

Electrochemical process combined with UV light irradiation for synergistic degradation of ammonia in chloride-containing solutions

An electrochemical process combined with ultraviolet light irradiation (UPE) using nonphotoactive dimensionally stable anodes (DSAs) like RuO 2/Ti and IrO 2/Ti in the presence of chlorides was investigated for ammonia degradation. In this process, the in situ electrogenerated active chlorine and in situ photogenerated chlorine radicals were responsible for the high efficiency of ammonia degradation. More than 97% of ammonia was converted to nitrogen and a significantly synergistic effect was confirmed. Compared with the single electrochemical (E) and photochemical (P) process, the degradation rates of ammonia and the average current efficiencies (ACEs) of the UPE process increased by 1.5 and 1.7 times using RuO 2/Ti and IrO 2/Ti electrodes, respectively. On the basis of the linear voltammograms, Electrochemical Impedance Spectra (EIS), UV–vis spectra, Electron Spin Resonance (ESR) analysis and a series of experiments designed, the synergistic mechanism was investigated. In addition, this unique process succeeded in transferring the reaction from the electrode surface to the bulk of the solution compared with the conventional photoelectrocatalytic (PEC) process. The loss of chloride decreased from 21.0% to 7.2% and the recycle of chloride was accelerated in the UPE process. Finally the effects of initial pH, current density and ammonia-nitrogen concentration were discussed. Results indicated that pH and ammonia concentration exerted little influences on the degradation rates and current density was the “rate-determining” factor.

Imidazol-2-yl Complexes of Cp*Ir as Bifunctional Ambident Reactants

Loss of chloride ion from imidazol-2-yl complex 4a activates the H-H bond of dihydrogen or the C-H bond of acetylene, forming an Ir(III) N-heterocyclic carbene (NHC) complex (3b or 9). Deprotonation of Ir(III) hydride 4b gives one new species, formulated as Ir(I) carbene complex 5. Protonation or alkylation of 5 occurs at the metal, returning the Ir(III) core of 6a,b. Deprotonation of cationic NHC complex 3a gives neutral imidazol-2-yl analogue 4a; as seen by X-ray diffraction, the Ir-C bond in 3a is shorter than that in 4a. These and other comparisons and interconversions of NHC complexes with an NH function and related imidazol-2-yl species expand the potential of NHC complexes by showing their bifunctional character.

Influence of dry and humid gaseous atmosphere on the thermal decomposition of calcium chloride and its impact on the remove of heavy metals by chlorination

In the last years chlorination has become an important industrial technique for the removal of heavy metal impurities (especially cadmium, copper, lead and zinc) in raw materials. In order to estimate the chlorination effect of different chlorine donors on heavy metals in sewage sludge ashes and the influence of gas humidity, the thermal decomposition behaviour of the chlorine donors was investigated. Therefore, thermal analysis of calcium chloride between 20 °C and 1400 °C in synthetic dry and humid flue gas atmosphere simulating firing methane with air was conducted in this work. In the first case the gas composition contained 12 v% oxygen, 5 v% carbon dioxide and 83 v% nitrogen whereas in the second case water vapour was added to the gas mixture in an amount to equal 10 v% of the total gas. In both cases (dry and humid flue gas), the first mass losses of calcium chloride up to 260 °C are based on the decomposition of its hydrates. Chlorine release occurs above the melting temperature of calcium chloride (782 °C) only: in the first case chlorine gas (Cl 2) by reaction of gaseous calcium chloride with oxygen and in the second case hydrogen chloride (HCl) by reaction with water vapour are formed. These different reaction products may influence the chlorination effect on heavy metals and further their removal in industrial processes. The solid reaction product is in both cases calcium oxide.

The Changes of Some Electrolytes after Two Months Activity

Some investigators have speculated that sodium chloride losses in sweat associated with net dehydration may lead to the observed hyponatremia after prolong strenuous exercise. The effects of altered hydration can influence athletes cognitively in addition to physically. In this research, rest alterations of sodium and potassium of blood serum have been investigated. The subjects were male students who have been selected purposefully. Variables of height, weight, age and body mass index (BMI) have been measured too. Participants took part in the training of incremental continuous running for 2 times in a week for 2 months. The running distance for subjects had been planned before performing main protocol training. The heart rate was controlled by polar watches. In the first and last session of training, the subjects’ oxygen consumption (VO2 max) was measured. The data analysis by means of paired sample t-test showed that: 1. The subjects’ sodium of serum had an increase of 2.21 mEq/L−1 even after 24 h. Its reason can be due to the loss of water and body fluids in the final session of training.2. The subjects’ potassium of rest serum had an increase of 0.13 m Eq L−1 that probably the extra- cellular potassium had returned into the intracellular. The observation suggested that accumulation of extra cellular potassium might be important for the development of fatigue in human muscles. We concluded that sodium of serum had an increased after 24 h. Its reason can be due to the loss of water and body fluids in the final session of training. The subjects’ potassium of rest serum had an increased that probably the extra-cellular potassium had returned into the intracellular. Also, this research recommends athletes must be used as dietary supplements in products designed to affect physical performance (ergogenic aids), their use should be considered.

The Hydrolysis Mechanism of the Anticancer Ruthenium Drugs NAMI-A and ICR Investigated by DFT−PCM Calculations

(ImH)[trans-RuCl(4)(DMSO-S)(Im)], (Im = imidazole, DMSO-S = S-bonded dimethylsulfoxide), NAMI-A, is the first anticancer ruthenium compound that successfully completed Phase I clinical trials. NAMI-A shows a remarkable activity against lung metastases of solid tumors, but is not effective in the reduction of primary cancer. The structurally similar (ImH)[trans-RuCl(4)(Im)(2)], ICR (or KP418), and its indazole analog (KP1019) are promising candidate drugs in the treatment of colorectal cancers, but have no antimetastatic activity. Despite the pharmacological relevance of these compounds, no rationale has been furnished to explain their markedly different activity. While the nature of the chemical species responsible for their antimetastatic/anticancer activity has not been determined, it has been suggested that the difference between reduction potentials of NAMI-A and ICR may be the key to the different biological responses they induce. In this work, Density Functional Theory calculations were performed to investigate the hydrolysis of NAMI-A and ICR in both Ru(III) and Ru(II) oxidation states, up to the third aquation. In line with experimental findings, our calculations provide a picture of the hydrolysis of NAMI-A and ICR mainly as a stepwise loss of chloride ligands. While dissociation of Im is unlikely under neutral conditions, that of DMSO becomes competitive with the loss of chloride ions as the hydrolysis proceeds. Redox properties of NAMI-A and ICR and of their most relevant hydrolytic intermediates were also studied in order to monitor the effects of biological reductants on the mechanism of action. Our findings may contribute to the identification of the active compounds that interact with biological targets, and to explain the different biological activity of NAMI-A and ICR.

Structures, Reductive Dechlorination, and Electron Affinities of Selected Polychlorinated Dibenzo-p-dioxins: Density Functional Theory Study

Density functional theory calculations were performed to obtain the structures, vertical electron affinities, and adiabatic affinities of 15 polychlorinated dibenzo-p-dioxins (PCDDs), including several extremely toxic congeners. A three-parameter hybrid density functional, B3LYP, was utilized with two different basis sets, 6-311G(d,p) and 6-311+G(2d,2p). The optimized structures of all PCDDs under consideration were planar, while all corresponding anions attained nonplanar geometries. One of the C-Cl bonds on each PCDD anion was considerably elongated, and the dechlorination of PCDDs occurred as the departing chlorine bent off the aromatic ring plane for effective pi-sigma orbital mixing. The characteristic electron energy-dependent regioselective chloride ion loss channels for 1,2,3,7,8-pentaCDD were elucidated by transition-state theory calculations. The relative low-energy barrier for the dechlorination of 1,2,3,7,8-pentaCDD indicated the high likelihood of obtaining reductive dechlorination (RD) products that are more toxic than the parent species. The calculated vertical electron affinities of PCDDs are consistent with the available experimental attachment energies, and the positive adiabatic electron affinities suggest that PCDDs may act as electron acceptors in living cells.

Imidazolium Carboxylates as Versatile and Selective N-Heterocyclic Carbene Transfer Agents: Synthesis, Mechanism, and Applications

N,N'-Disubstituted imidazolium carboxylates, readily synthetically available, isolable, air- and water-stable reagents, efficiently transfer N-heterocyclic carbene (NHC) groups to Rh, Ir, Ru, Pt, and Pd, to give novel NHC complexes, e.g., [Pd(NHC)3OAc]OAc and [Pt(NHC)3Cl]Cl (NHC = 1,3-dimethyl imidazol-2-ylidene). The NHC esters are also effective. Tuning the reaction conditions for NHC transfer can give either mono- or bis-NHCs, or bis- and tris-NHCs. A net N to C rearrangement of the N-alkyl imidazole complex to the corresponding NHC complex was seen with (MeO)2CO (DMC). DFT calculations identify the steps needed to form the carboxylate from imidazole and DMC: SN2 methyl transfer from DMC to imidazole, followed by proton transfer from the imidazolium CH to the carboxylate counterion, produces the free NHC H-bonded to MeOH with a weakly associated CO2. The nucleophilic NHC attacks CO2 to form NHC-CO2. NHC transfer to the metal with loss of CO2 has been calculated for Rh(cod)Cl. A proposed two-cis-site reactivity model rationalizes the experimental data: two such vacant sites at the metal are needed to allow coordination of the NHC-CO2 carboxylate and subsequent CC cleavage with NHC transfer. Partial cod decoordination or chloride loss is thus required for Rh(cod)Cl. Chloride dissociation, calculated to be easier in polar solvent, is confirmed experimentally from the retarding effect of excess chloride.

Photocatalytic Hydrogen Production from Water Employing A Ru, Rh, Ru Molecular Device for Photoinitiated Electron Collection

A molecular device for photoinitiated electron collection at a metal center, [{(bpy)2Ru(dpp)}2RhCl2](PF6)5, has been studied and shown to photocatalytically produce H2 from H2O. This system absorbs visible light and in the presence of an electron donor is reduced by multiple electrons. In the presence of water, the [{(bpy)2Ru(dpp)}2RhCl2](PF6)5 system photocatalytically produces H2 that varies linearly with photolysis time. The photocatalyst functions in the presence of chloride, but the yield of H2 is lower, consistent with chloride loss being important in the photocatalysis cycle

Exertional Heat Cramps: Recovery and Return to Play

In contrast to muscle cramps that are brought on by muscle overload or fatigue, exertional heat cramps seem to be prompted by extensive sweating and a significant sweat-induced whole-body sodium deficit. As a result of a consequent contracted interstitial compartment, axon terminals of selected motor neurons can become hyper-excitable and spontaneously discharge. Barely detectable muscle fasciculations or "twitches" in the affected muscles can rapidly progress to debilitating muscle cramps in just 20 to 30 minutes. To aid recovery, salt (NaCl) and water lost from sweating should be sufficiently replaced so as to restore the extracellular volume and interstitial fluid spaces. Sweat sodium, chloride, and fluid losses incurred during training and competition need to be closely matched by daily salt and fluid intake, in order to prevent an excessive sodium deficit, maintain sufficient fluid balance, and avoid exertional heat cramps.

Pd-Mediated Activation of Molecular Oxygen: Pd(0) versus Direct Insertion

In developing environmentally benign chemistries, it is most important to use dioxygen directly in lieu of toxic and/or corrosive stoichiometric oxidants. Unfortunately, for many processes such direct oxidations have not yet become practical. To help develop such processes, we elucidate here the mechanism for the reaction of molecular oxygen with toluene-solvated palladium-hydride complex using quantum mechanics (B3LYP/LACVP** with the PBF polarizable continuum solvent model) for Pd(II-)((-)sparteine)(H)(Cl) in the presence of base, specifically focusing on the pathways proceeding through Pd(0). The lowest barrier Pd(0) pathway proceeds through a rate-determining base-assisted deprotonation of the palladium, followed by the association of molecular oxygen and the subsequent loss of chloride, forming the corresponding eta(2)-peroxo-palladium complex. We also examine the spin transition and the completion of the reaction to form PdCl(2) and H2O2. Together with our previously published Pd-H/O2 direct insertion mechanism, these reports provide a complete mapping of the possible pathways for reoxidation of palladium hydride with molecular oxygen. For this particular system, we conclude that direct insertion is preferred (DeltaDeltaH++ = 6.2 kcal/mol, DeltaDeltaG++ = 7.5 kcal/mol) and trace this preference to the bidentate character of sparteine and the lack of pi-accepting ligands. Suggestions are included for how this preference can be switched.

Studies of the electrochemical reduction of atrazine on a mercury electrode in acid medium: An electrochemical and NMR approach

Abstract The reduction of atrazine on mercury shows an irreversible behaviour involving two electrons per molecule and the loss of chloride ions when studied under standard square wave voltammetry conditions. Meanwhile, tests carried out at frequencies well above 100 s−1 revealed a marked degree of reversibility not compatible with the well-documented and very fast cleavage of the C–Cl for this type of molecule. Controlled potential electrolyses at different potentials indicated the initial transfer of two electrons per atrazine molecule but this value changed to four after a short period. The electrolyses products were analyses by 1H NMR and a new mechanistic scheme is proposed.

Evaluation of corrosion resistance of Portland pozzolana cement and fly ash blended cements in pre-cracked reinforced concrete slabs under accelerated testing conditions

In this paper, attempts have been made to analyse the corrosion characteristics of three kinds of cements, namely ordinary Portland cement (OPC), pozzolana Portland cement (PPC) and 25% fly ash replaced in ordinary Portland cement (FA) by designing two grades of concrete, M20 and M40 mixes under accelerated exposure conditions. Reinforced concrete slabs of size 900 mm × 180 mm × 100 mm were cast, cured and pre-cracked to crack width of 0 mm and 0.10 mm, exposed to accelerated testing conditions in 3% NaCl environments and evaluated for their corrosion resistance using various electrochemical tests like open circuit potential, linear polarization technique, free chloride, alkalinity and weight loss measurements and the results obtained were discussed in detail.

The effects of tree establishment on water and salt dynamics in naturally salt-affected grasslands

Plants, by influencing water fluxes across the ecosystem-vadose zone-aquifer continuum, can leave an imprint on salt accumulation and distribution patterns. We explored how the conversion of native grasslands to oak plantations affected the abundance and distribution of salts on soils and groundwater through changes in the water balance in naturally salt-affected landscapes of Hortobagy (Hungary), a region where artificial drainage performed approximately 150 years ago lowered the water table (from -2 to -5 m) decoupling it from the surface ecosystem. Paired soil sampling and detailed soil conductivity transects revealed consistently different salt distribution patterns between grasslands and plantations, with shallow salinity losses and deep salinity gains accompanying tree establishment. Salts accumulated in the upper soil layers during pre-drainage times have remained in drained grasslands but have been flushed away under tree plantations (65 and 83% loss of chloride and sodium, respectively, in the 0 to -0.5 m depth range) as a result of a five- to 25-fold increase in infiltration rates detected under plantations. At greater depth, closer to the current water table level, the salt balance was reversed, with tree plantations gaining 2.5 kg sodium chloride m(-2) down to 6 m depth, resulting from groundwater uptake and salt exclusion by tree roots in the capillary fringe. Diurnal water table fluctuations, detected in a plantation stand but not in the neighbouring grasslands, together with salt mass balances suggest that trees consumed approximately 380 mm groundwater per year, re-establishing the discharge regime and leading to higher salt accumulation rates than those interrupted by regional drainage practices more than a century ago. The strong influences of vegetation changes on water dynamics can have cascading consequences on salt accumulation and distribution, and a broad ecohydrological perspective that explicitly considers vegetation-groundwater links is needed to anticipate and manage them.

테플론 여과지를 이용한 미세입자 무기이온 성분 측정에서의 오차 정량

Artifacts due to inter-particle and gas-particle interactions during PM2.5 sampling were quantified by comparing the measurement results between the annular denuder-filterpack system and the filterpack system without denuder. Measurements were carried in Seoul for 10 days in each season; Nov. 2004, Jan. 2005, Mar. 2005, and Jul. 2005, respectively. In each day, two 12-h samples were obtained. The concentrations of nitrate and chloride showed seasonal variations mainly due to the availability of ammonium to neutralize nitrate or chloride. Nitrates and chloride losses were prominent in summer. Since most of ammonia was used to neutralize sulfuric acid and formed ammonium sulfate in summer, nitrate and chloride could not exist in particles and ammonium loss was smaller than other seasons.