Stability of K-struvite in High Temperature and Acid-base Environment

K-struvite was prepared by precipitation method,and the stability of K-struvite in high temperature and acid-base environment were investigated by X-ray diffraction(XRD),thermogravimetric analysis(TG/DSC),and infrared spectroscopy(FT-IR).The results show that K-struvite decomposes from 50 to 110℃,and the mass loss begins at 50℃before being completely destroyed at 110℃,then further heating at temperature above 500℃leading to complete loss of the binding water in K-struvite.Moreover,K-struvite is more stable in alkaline environments than acidic environment.

Comparative Study on the Acid-Base Indicator Properties of Natural Dye, Turmeric Rhizome (Curcuma longa) and Synthetic Dyes

Acid-Base Indicator, Turmeric Rhizome (Curcuma longa) was extracted from the root of a turmeric plant. The turmeric was peeled, washed and dried in an oven at 60°C. It was ground into powder and soaked in hot and cold ethanol for the extraction. The extract was filtered and part of it was concentrated to yield a reasonable quantity of turmeric indicator. On standardization of acid with a base, 0.05 M base respectively of Sodium hydroxide (NaOH), sodium carbonate (Na2CO3) and Disodium borate (B4Na2O7) were used. Hot and cold extracts of turmeric were used as indicators and were compared with methyl orange and phenolphthalein. On the preliminary test carried out, hot and cold turmeric indicator showed yellow colour in acid medium and orange colour in the base. Methyl orange showed red colour in acid but yellow in the base, phenolphthalein was colourless in acid but pink in the base. During titration there were colour changes at the end points in the entire test carried out. The average volumes at ends points were calculated, the molar concentrations and mass concentrations of the acids used were also determined. The results showed that there was no difference between the natural indicators used and the existing synthetic indicators which are toxic to our environment.

Application of Amino Acid-Based Surfactant in Dishwasher Detergent

The application of amino acid-based surfactant in dishwasher detergent was studied in this paper. The foam and oil-removing performance of amino acid surfactants in alkaline condition were test to discuss feasibility of amino acid-based surfactant from natural origin as the alternative to traditional nonionic surfactants from petroleum origin in dishwasher detergent. Comparative study was conducted through using various amino acid-based surfactants and nonionic surfactants respectively, together with enzymes and peroxide to formulate dishwasher detergents, and their application properties such as foam performance and detergency were also evaluated when washing different tableware in automatic dishwasher. The results showed that among all tested amino acid surfactants, glutamate surfactants showed low foaming and high oil-removing ability in alkaline condition, and excellent decontamination ability in dishwashing tests.

Determination of pKa values of alendronate sodium in aqueous solution by piecewise linear regression based on acid-base potentiometric titration

As a mono-sodium salt form of alendronic acid,alendronate sodium presents multi-level ionization for the dissociation of its four hydroxyl groups.The dissociation constants of alendronate sodium were determined in this work by studying the piecewise linear relationship between volume of titrant and p H value based on acidbase potentiometric titration reaction.The distribution curves of alendronate sodium were drawn according to the determined p Ka values.There were 4 dissociation constants(pKa_1=2.43,pKa_2=7.55,pKa_3=10.80,pKa_4=11.99,respectively) of alendronate sodium,and 12 existing forms,of which 4 could be ignored,existing in different p H environments.

Acid-base characterization of foursulfide minerals

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Prospects for nucleic acid-based therapeutics against hepatitis C virus

In this review,we discuss recent advances in nucleic acid-based therapeutic technologies that target hepatitis C virus(HCV)infection.Because the HCV genome is present exclusively in RNA form during replication,various nucleic acid-based therapeutic approaches targeting the HCV genome,such as ribozymes,aptamers,siRNAs,and antisense oligonucleotides,have been suggested as potential tools against HCV.Nucleic acids are potentially immunogenic and typically require a delivery tool to be utilized as therapeutics.These limitations have hampered the clinical development of nucleic acid-based therapeutics.However,despite these limitations,nucleic acid-based therapeutics has clinical value due to their great specificity,easy and large-scale synthesis with chemical methods,and pharmaceutical flexibility.Moreover,nucleic acid therapeutics are expected to broaden the range of targetable molecules essential for the HCV replication cycle,and therefore they may prove to be more effective than existing therapeutics,such as interferon-αand ribavirin combination therapy.This review focuses on the current status and future prospects of ribozymes,aptamers,siRNAs,and antisense oligonucleotides as therapeutic reagents against HCV.

Has Stewart approach improved our ability to diagnose acid-base disorders in critically ill patients?

The Stewart approach-the application of basic physicalchemical principles of aqueous solutions to blood-is an appealing method for analyzing acid-base disorders. These principles mainly dictate that p H is determined by three independent variables, which change primarily and independently of one other. In blood plasma in vivo these variables are:(1) the PCO2;(2) the strong ion difference(SID)-the difference between the sums of all the strong(i.e., fully dissociated, chemically nonreacting) cations and all the strong anions; and(3) the nonvolatile weak acids(Atot). Accordingly, the p H and the bicarbonate levels(dependent variables) are only altered when one or more of the independent variables change. Moreover, the source of H+ is the dissociation of water to maintain electroneutrality when the independent variables are modified. The basic principles of the Stewart approach in blood, however, have been challenged in different ways. First, the presumed independent variables are actually interdependent as occurs in situations such as:(1) the Hamburger effect(a chloride shift when CO2 is added to venous blood from the tissues);(2) the loss of Donnan equilibrium(a chloride shift from the interstitium to the intravascular compartment to balance the decrease of Atot secondary to capillary leak; and(3) the compensatory response to a primary disturbance in either independent variable. Second, the concept of water dissociation in response to changes in SID is controversial and lacks experimental evidence. In addition, the Stewart approach is not better than the conventional method for understanding acid-base disorders such as hyperchloremic metabolic acidosis secondary to a chloride-rich-fluid load. Finally, several attempts were performed to demonstrate the clinical superiority of the Stewart approach. These studies, however, have severe methodological drawbacks. In contrast, the largest study on this issue indicated the interchangeability of the Stewart and conventional methods. Although the introduction of the Stewart approach was a new insight into acid-base physiology, the method has not significantly improved our ability to understand, diagnose, and treat acid-base alterations in critically ill patients.

Study on acid-base disorders in patients with adult respiratory distress syndrome

Arterial blood gases and electrolytes were determined in 159 cases of adult respirato-ry distress syndrome(ARDS).It was found that disordered acid-base balance was a commonfinding in various kinds of ARDS.In mild ARDS,respiratory alkalosis and the combination ofrespiratory alkalosis plus metabolic alkalosis or metabolic acidosis were usually encounted,whilein moderate and severe cases of ARDS,triple acid-base disorders,respiratory acidosis,and thecombination of respiratory acidosis plus metabolic acidosis were commonly seen.Severe alkalosiswas one of the factors to result in death.

Facile synthesis of metal-organic frameworks embedded in interconnected macroporous polymer as a dual acid-base bifunctional catalyst for efficient conversion of cellulose to 5-hydroxymethylfurfural

5-Hydroxymethylfurfural(5-HMF),as a key platform compound for the conversion of biomass to various biomass-derived chemicals and biofuels,has been attracted extensive attention.In this research,using Pickering high internal phase emulsions(Pickering HIPEs)as template and functional metal-organic frameworks(MOFs,UiO-66-SO;H and UiO-66-NH;)/Tween 85 as co-stabilizers to synthesis the dual acid-base bifunctional macroporous polymer catalyst by one-pot process,which has excellent catalytic activity in the cascade reaction of converting cellulose to 5-HMF.The effects of the emulsion parameters including the amount of surfactant(ranging from 0.5%to 2.0%(mass)),the internal phase volume fraction(ranging from 75%to 90%)and the acid/base Pickering particles mass ratio(ranging from 0:6 to 6:0)on the morphology and catalytic performance of solid catalyst were systematically researched.The results of catalytic experiments suggested that the connected large pore size of catalyst can effectively improve the cellulose conversion,and the synergistic effect of acid and base active sites can effectively improve the 5-HMF yield.The highest 5-HMF yield,about 40.5%,can be obtained by using polymer/MOFs composite as catalyst(Poly-P12,the pore size of(53.3±11.3)μm,the acid density of 1.99 mmol·g^(-1)and the base density of 1.13 mol·g^(-1))under the optimal reaction conditions(130℃,3 h).Herein,the polymer/MOFs composite with open-cell structure was prepared by the Pickering HIPEs templating method,which provided a favorable experimental basis and theoretical reference for achieving efficient production of high addedvalue product from abundant biomass.

Association of Acid-Base Balance in the Renal Proximal Tubule and Blood Pressure Alterations: Potential Role of Local Mediators

Disturbances in acid-base balance leading to the development of hypertension are currently gaining increased attention among researchers. Perturb acid-base balance characterized by metabolic acidosis has been demonstrated in hypertensive animals and humans. Research suggests that acid-base changes are not only the consequences of elevated blood pressure but can precede the development of hypertension. However, no exact mechanism has been identified to link acid-base imbalance with alterations in blood pressure. The kidney proximal tubule is the major site for maintaining normal bicarbonate concentrations which is an important component of acid-base balance. Acid-base transporter proteins in the renal proximal tubule such as Na+/HCO-3?cotransporters, Na+/H+ exchangers, and anion-exchangers play important roles in controlling acid secretion, ammonia production and bicarbonate reabsorption for maintaining acid-base balance. It is well known that sodium retention in the renal tubules leads to increase in blood volume and consequently increases in blood pressure. Therefore, it is the purpose of this review to discuss the role of sodium-coupled acid-base transporters in regulating proximal tubular sodium retention and controlling blood pressure homeostasis. We will also focus on the capacity of local mediators;angiotensin II, cortisol, prosta-glandin and aldosterone, to regulate acid-base and blood pressure homeostasis.

Blood Chemistry, Acid-Base, Electrolyte, Blood Lactate Metabolism and Sleep at 3480 m in Mountain Marathon Runners

Altered blood chemistry, acid-base and electrolyte are suggested determinants of sleep disturbance, with frequent arousal at high altitude even in well and long-trained altitude marathon runners. In this sample of experienced altitude marathon runners with maximal aerobic power at sea level of 61.4 ± 2.7 ml/kg-1·min-1 we found that pO2 and percent of oxygen saturation (%SO2) were lower at2050 mand3480 mthan at sea level;pO2 was higher after 38 - 41 hours than after 30 - 31 hours of acclimatization at3480 m(P 2 decreased (P 2 and (P 2 at a sleeping altitude of3480 mwas lower (P Simple regression analysis disclosed a significant correlation between the changes in TST and the percent of REM sleep and the changes in %SpaO2 recorded during sleep (P 2 at higher altitude and the percent of W and of TST (P 2, tCO2 and [HCO3-] correlated negatively and significantly with the percent of REM sleep changes at high altitude (P 2 and pH and correlated negatively with the changes in %SO2, pCO2, tCO2, and [HCO3-] (P ++] and [BE] and negatively with the changes in buffered bases [BB] and [BEeffective] (P 2 and significantly and negatively with the changes in [K+] (P 2, tCO2, [HCO3-] and [K+]

Investigation of a Simple and Cheap Source of a Natural Indicator for Acid-Base Titration: Effects of System Conditions on Natural Indicators

This study investigated a natural indicator for acid-base titration which is extracted from guinea corn leaves popularly called “waakye leaves” in Ghana. Four types of acid-base titration were studied: strong acid versus (v/s) strong base, strong acid versus weak base, weak acid versus strong base, and weak acid versus weak base. The indicator color change, pH range and the average titre values were determined for each type of acid-base titration. These values were comparable to those obtained from three standard indicators: methyl orange, methyl red and phenolphthalein. Total flavonoids (TF) and condensed tannin (CT) from the crude leaves extract were determined which might be the major reasons for the activity of the extract as an indicator for simple acid-base titration. The authors suggest that the natural indicator is cheap, available, simple to extract, user and environmentally friendly and could be an excellent replacement for standard indicators.

The Roles of Key Electrolytes in Balancing Blood Acid-Base and Nutrient in Broiler Chickens Reared under Tropical Conditions

The loss of electrolyte balance in diets of broiler chickens has resulted in a serious distur-bance of blood acid-base balance, coupled with elevated body temperature. The body losses carbon dioxide (CO2) and bicarbonate (HCO3), resulting in respiratory alkalosis or acidosis. Under tropical conditions of high environmental temperatures, the balance of electrolytes in feeds must be set much higher as to maintain equal metabolic and digestive efficiency. However, information on the ideal dietary electrolyte balance (DEB) that could effectively correct acid-base imbalance in broiler chickens under severe heat stress condition is scanty. Therefore, the effects of varying electrolyte balance in diets on haematology, blood glucose and serum inorganic elements were assessed in broiler chickens at starter (0 - 21 d) and finisher (22 - 35 d) phases, under temperature-humidity index of 24.97 - 35.19. One day-old Arbor Acre chicks (n = 300) were procured and randomly allotted to diets supplemented with potassium chloride and sodium bicarbonate, to balance monovalent ions (sodium, potassium and chloride) at 210 (T1), 240 (T2), 270 (T3), 300 (T4), 330 (T5) and 360 (T6) mEq/kg DEB, in a completely randomised design. On days 21 and 35, blood (5 mL) samples were collected from birds in each replicate whose weights were closest to the mean class weight for haematology and serum biochemical indices using standard procedures. Data were analysed using descriptive statistics and ANOVA at α = 0.05. Different levels of DEB did not significantly affect (P > 0.05) haematology and blood glucose at starter phase. However, at finisher phase, heterophil: lymphocyte of birds on 270 and 240 mEq/kg DEB were lower (P < 0.05) compared to other dietary treatments. Blood acid-base balance was relatively enhanced in birds on aggregate DEB level of 360 mEq/kg with reduced chloride ion and relatively lower incidence of hemodilution with respect to high haemoglobin levels as this level is advantageous in balancing blood acid to base ratio in broiler chickens reared under severe environmental temperatures higher than 43?C ± 5?C as against some previous opinions that did not take into consideration, the inherent dietary electrolyte balance in feedstuff, other functional mono or divalent ions, and the severity of environmental factors.

Double Acid-Base Extraction of Silicic Acid from Quartz Sand

Silica is becoming more attractive as plant nutrient for non-graminae crops particularly in relation with drought-stress tolerant. Many efforts have been conducted to obtain an efficient technique to produce silica fertilizer worldwide, but the results are varying considerably due to various factors including raw material and extraction technique. This study was carried out to develop an efficient extraction technique for ortho-silicic acid (OSA-H4SiO4) from a Bangka-Belitung quartz sand by employing acid-base dissolution method. A 325-mesh size quartz sand was boiled in HCl solution at various concentrations. The optimum concentration was then used in the following experiment at several different volumes of solution. The sand obtained from optimum concentration and volume of HCl solution was then reacted with different amounts of NaOH (s), and heated until a wet mixture was obtained. As a reference the best extraction conditions were applied to a natural zeolite sample. All OSA analyses were done in triplicates with spectrophotometric method. Supporting evidences were collected from x-ray diffraction and scanning-electron-microscopy analyses of the treated samples. The yield of quartz sand-originated OSA was 183 g·kg-1 and significantly increased linearly with increasing weight of NaOH (R2 = 0.99**), whereas that from zeolite was only 104.2 g·kg-1 at 80 g NaOH. XRD and SEM data confirmed the evidences that the acid-base extraction disrupted the quartz mineral structure and as a consequence releasing more water soluble OSA.

Acid-base alternation diagenesis and its influence on shale reservoirs in the Permian Lucaogou Formation, Jimusar Sag, Junggar Basin, NW China

The diagenesis and diagenetic facies of shale reservoirs in Lucaogou Formation of Jimusar Sag were studied by means of microscopic observation and identification of ordinary thin sections and cast thin sections,X-ray diffraction,scanning electron microscope and electron probe tests.The results show that alkaline and acidic diagenetic processes occurred alternately during the deposition of Permian Lucaogou Formation in Jimusar Sag.The evolution of porosity in the shale reservoirs was influenced by compaction and alternate alkaline and acidic diagenetic processes jointly,and has gone through three stages,namely,stage of porosity reduction and increase caused by alkaline compaction,stage of porosity increase caused by acid dissolution,and stage of porosity increase and reduction caused by alkaline dissolution.Correspondingly,three secondary pore zones developed in Lucaogou Formation.The shale reservoirs are divided into three diagenetic facies:tuff residual intergranular pore-dissolution pore facies,tuff organic micrite dolomite mixed pore facies,and micrite alga-dolomite intercrystalline pore facies.With wide distribution,good pore structure and high oil content,the first two facies are diagenetic facies of favorable reservoirs in Lucaogou Formation.The research results provide a basis for better understanding and exploration and development of the Lucaogou Formation shale reservoirs.

Triphenylmethanol and Tris(2-(hydroxymethyl)phenol) Derivatives: Synthesis and Application as Indicators for Acid-Base Volumetric Titration

Polyphenols are naturally occurring compounds found largely in fruits, vegetables, cereals and beverages. Currently, there is much interest in the potential health benefits of dietary plant polyphenols as antioxidants. The effect of polyphenols on human cancer cells is most often protective and induces a reduction in the number of tumors or rate of growth. During our course of study on anticancer prodrugs, twelve triphenylmethanol and one tris(2-(hydroxymethyl) phenol derivatives were synthesized as a carrier of several drugs with optimized lipophilicity. Besides application of these compounds as a foundation for anticancer drug delivery systems, these compounds were evaluated as indicators for the acid-base volumetric titration of a standard solution of hydrochloric acid with a standard solution of sodium hydroxide. The experiments indicated a moderate-to-sharp color transition of the solutions near the neutralization point for most indicators. These indicators may have potential applications for acid-base titrations in a narrow range.

Non-covalent Bonded 3D Supramolecular Architectures Based on Acid-base Adducts

Two novel acid-base adducts,[H_2L_1^(2+)](Hpbda)_2(1,L_1 = l,4-di(lH-imidazol-4-yl)benzene,H_2pbda = 1,4-benzenedicarboxylic acid) and[H_2L_2^(2+)](NO_3)_2(2,L_2 = l,4-di(l-carboxymethyl-imidazol-4-yl)benzene),have been prepared and characterized by single-crystal X-ray diffraction,IR spectroscopy and elemental analysis.Compound 1 crystallizes in monoclinic,space group P2_1/n with a = 5.3525(11),b = 9.1471(19),c = 19.314(4) ?,β = 92.342(3)°,V= 944.8(3) ?~3,Z = 2,C_(16)H_(16)N_6O_(10),M_r = 452.35,D_c = 1.590 g/cm^3,μ = 0.135 mm^(-1),S = 1.058,F(000) = 468,the final R = 0.0661 and wR = 0.1887 for 2298 observed reflections(I> 2σ(I)).Compound 2 crystallizes in monoclinic,space group P2_1/c with a = 9.6923(10),b = 17.2950(17),c = 7.1880(7) ?,β =94.801(2)°,V= 1200.7(2) ?~3,Z = 2,C_(28)H_(22)N_4O_8,M_r = 542.50,D_c = 1.501 g/cm^3,μ = 0.112 mm^(-1),S= 1.060,F(000) = 564,the final R = 0.0394 and wR = 0.1017 for 2768 observed reflections(I >2σ(I)).In the title compounds,both of L_1 and L_2 ligands act as weak base to accept protons to exhibit diprotonated H_2L_1^(2+) and H_2L_2^(2+) form,which can effectively employ as hydrogen bonding donors to combine anion moieties to form binary adducts respectively.In the crystal packing diagram of two polymers,there exist extensive noncovalent interactions including charge-transfer interactions,C(N)-H…π and N-H…O,C-H…O,O-H…O hydrogen bonding interactions between co-crystal moieties which consolidate the structures of supramolecular polymers,thus generating three-dimensional(3D) frameworks.

Two Dehydroabietic Acid-based Arylamines: Synthesis, Crystal Structure and Fluorescent Properties

Two dehydroabietic acid-based arylamines have been synthesized and characterized by FTIR, 1H NMR, 13C NMR, MS spectra and elemental analysis. Their spatial structures were determined by X-ray diffraction analysis. UV-Vis absorption and fluorescence spectral characteristics of these compounds in methanol were investigated. Their fluorescence emission spectra in different polarity solvents were further evaluated. Fluorescent properties and structural relationship of the compounds showed that fluorescence intensity and quantum yield inversely increase with the non-coplanar degree. In addition, the solvent polarity has different effects on the fluorescence emission spectra of two compounds.

Hepatic encephalopathy complicated with hyponatremia and acid-base disturbance and its prognosis

Objective:To improve the diagnosis and therapeutic effect of occurrence and development of hyponatremia and disorder of acid-base balance among patients with hepatic encephalopathy(HE) by elucidating the regularity and mechanism,as well as its influence on prognosis.Methods:327 HE patients admitted to our hospital from January 1990 to June 2010 were enrolled.Meanwhile 316 patients hospitalized in the medical department of the same hospital were chosen as the control group.Patients in both groups were given the same methods to measure arterial blood gas parameters(pH value,PaCO2,[HCO3-],TCO2,BE and SaO2),blood biochemistry([Na+],[K+],[Cl-]),liver function,kidney function and blood glucose,serum sodium,and thereupon tocalculate the anion gap(AG) and the potential [HCO3-],and acid-base balance disorder.Results:Among the 327 HE patients,hyponatremia was found in 188 cases(57.4%),of whom 132 patients died(70.2%).While among the 316 patients in control group,68 presented with hyponatremia(21.5%),and 19 died(27.9%).The incidence and mortality were significantly different between the two groups(P<0.001).All the 327 patients presented with different degrees of acid-base balance disorder and 178 died(54.4%),in whom 164(50.2%) belonged to simple acid-base balance disorder and 74(45.1%) died,136(41.6%) were dual acid-base balance disorder and 80(58.8%) died,27(8.2%) were triple acid-base disturbance and 24(88.9%) died.Whereas in the control group only 83 patients(26.2%) were recognized as simple and dual acid-base balance disorder,and 18(21.7%) died.There was higher incidence of acid-base balance disorder and mortality rate in HE group than control one(P<0.001).Conclusion:Hyponatremia is valuable to judge HE patients' prognosis.The key parameters in the judgment and evaluation on acid-base balance disorder among HE patients are the change of pH values and serum electrolyte values.When pH value ≤ 7.30 or > 7.55,it generally suggests a poor prognosis.

Acid-base cooperativity of heterogeneous catalyst containing acidic framework and sterically hindered base for aldol condensation

A bifunctional heterogeneous catalyst containing two mutually incompatible acidic and basic sites,which exhibits cooperative catalytic behavior in the aldol condensation of acetone and various aldehydes,was synthesized by postgrafting of 1,5,7- triazabicyclo[4.4.0]dec-5-ene(TBD,a sterically hindered organic base) onto Al-MCM-41 molecular sieve.