Electrochemical oxidation behavior of bisphenol A at surfactant/layered double hydroxide modified glassy carbon electrode and its determination

Electrochemical behavior of bisphenol A (BPA) at glassy carbon electrode-modified with layered double hydroxide (LDH) and anionic surfactant (sodium dodecyl sulfate) is investigated by electrochemical techniques. Compared with the bare electrode and LDH-modified electrode, the oxidation peak potential of BPA shifted negatively and the peak current increased significantly due to the enhanced accumulation of BPA via electrostatic interaction with LDH at the hydrophobic electrode surface. Some determination conditions such as LDH loading, pH, scan rate, accumulation potential, and accumulation time on the oxidation of BPA were optimized. And some kinetic parameters were investigated. Under the optimized conditions, the oxidation current was proportional to BPA concentration in the range of 8 × 10⁻⁹ to 2.808 × 10⁻⁶ M with the detection limit of 2.0 × 10⁻⁹ M by amperometry. The fabricated electrode showed good reproducibility, stability, and anti-interference. The proposed method was successfully applied to determine BPA in water samples, and the results were satisfactory.     

Preparation of magnetic molecularly imprinted polymer for rapid determination of bisphenol A in environmental water and milk samples

A magnetic molecularly imprinted polymer (M-MIP) of bisphenol A (BPA) was prepared by miniemulsion polymerization. The morphological and magnetic characteristics of the M-MIP were characterized by Fourier-transform infrared spectroscopy, transmission electron microscopy, and vibrating sample magnetometry. The adsorption capacities of the M-MIP and the nonimprinted polymer were investigated using static adsorption tests, and were found to be 390 and 270 mg g⁻¹, respectively. Competitive recognition studies of the M-MIP were performed with BPA and the structurally similar compound DES, and the M-MIP displayed high selectivity for BPA. A method based on molecularly imprinted solid-phase extraction assisted by magnetic separation was developed to extract BPA from environmental water and milk samples. Various parameters such as the mass of sorbent, the pH of the sample, the extraction time, and desorption conditions were optimized. Under selected conditions, extraction was completed in 15 min. High-performance liquid chromatography with UV detection was employed to determine BPA after the extraction. For water samples, the developed method exhibited a limit of detection (LOD) of 14 ng L⁻¹, a relative standard deviation of 2.7% (intraday), and spiked recoveries ranging from 89% to 106%. For milk samples, the LOD was 0.16 μg L⁻¹, recoveries ranged from 95% to 101%, and BPA was found in four samples at levels of 0.45–0.94 μg L⁻¹. The proposed method not only provides a rapid and reliable analysis but it also overcomes problems with conventional solid-phase extraction (SPE), such as the packing of the SPE column and the time-consuming nature of the process of loading large-volume samples.     

Application of SPME to the determination of alkylphenols and bisphenol A in cyanobacteria culture media

In order to survey the influence of estrogenic compounds on cyanobacteria, solid-phase microextraction (SPME) with a carbowax-divinylbenzene fibre was used for the determination of tert-octylphenol (tert-OP), n-nonylphenol (n-NP), technical nonylphenol (tech-NP) and bisphenol A (BPA) in cyanobacteria culture media by gas chromatography with flame ionization detection. Determinations were carried out without derivatization in deionized water and filtered culture media. A comparison between f2 and Fraquil culture media was performed, which showed that only f2 allowed quantitative recoveries. Headspace SPME with salting out, requiring only 10 mL of sample, was suitable for tert-OP, n-NP, and tech-NP determination with limits of detection (LOD) of <0.05 μg L⁻¹. For BPA, direct immersion SPME could provide a LOD of 1 μg L⁻¹. Automated sampling allowed reproducible extraction. No exudate substances overlapped with the studied compounds during the chromatographic separation and no matrix effects were observed. Ecotoxicity tests can be performed by single spiking of tert-OP and tech-NP and multiple spiking of n-NP due to its lower stability.     

Synthesis of <Emphasis Type="Italic">N</Emphasis>-[(1,1-dimethyl-2-acetyl)ethyl]-β-dihydroxyethylamine and study of the kinetics of the Michael addition reaction of diacetone acrylamide with diethanolamine

A new crosslinker, N-[(1,1-dimethyl-2-acetyl)ethyl]-β-dihydroxyethylamine (DDP), which contains two hydroxyl groups and carbonyl, was successfully synthesized by Michael addition reaction between diacetone acrylamide (DAAM) and diethanolamine (DEA) in different solvents. This crosslinker could crosslink during film formation through a reaction between ketone and hydrazide. The structure of DDP was characterized by IR and NMR, and effects of solvents, temperature, and reaction time on the yield of DDP were determined. The reaction kinetics including the order of the reaction and apparent activation energy were also investigated. Under the experimental conditions chosen (temperature 90 °C, reaction time 12 h), the crosslinker was obtained in 75.28% yield. The reaction was a second-order reaction and the apparent activation energy was 91.0 kJ mol⁻¹. The reaction rate constants were 0.11 mol⁻¹ dm³ h⁻¹ at 90 °C and 0.03 mol⁻¹ dm³ h⁻¹ at 75 °C.     

Theoretical studies on the chemical decomposition of 5-aza-2′-deoxycytidine: DFT study and Monte Carlo simulation

The decomposition mechanism of 5-Aza-2′-deoxycytidine has been studied by the use of computational techniques. Optimized structures for all of the stationary points in the gas phase were investigated at B3LYP/6-31+G(d,p) level of theory. Single-point energies were determined employing the ab initio MP2 method in conjunction with the 6-311++G(d,p) basis set. Five possible pathways, paths 1–5, were evaluated. In each pathway, the direct (A-paths 1–5) and water-assisted (B-paths 1–5) processes were considered. Meanwhile, the local microhydration model with the direct participation of three water molecules around the reaction centers was adopted to mimic the system for the water-assisted decomposition mechanisms above, where one water molecule is the nucleophilic reactant and the other two are the auxiliary molecules located on each side of the nucleophilic water. The results in the gas phase exhibit that the energy barriers of the water-assisted pathways based on the local microhydration model decrease dramatically by about 15–20 kcal/mol as compared with those of the direct pathways because of the contribution of the auxiliary water molecules. In addition, bulk solvent effects of water were determined by means of the self-consistent reaction field based on the conductor-like polarized continuum model and Monte Carlo simulation with free energy perturbation (MC-FEP) technique, respectively. Our computational results indicate that B-path 3 in the decomposition reaction of 5-azadC is the most favorable, where the calculated rate constant (1.68 × 10⁻³ min⁻¹) using the MC-FEP method is within the range of the experimentally determined values [(5.89 ± 0.54) × 10⁻³ min⁻¹ by UV and (1.46 ± 0.08) × 10⁻³ min⁻¹ by NMR].     

Chemiluminescence determination of metformin based on hydroxyl radical reaction and molecularly imprinted polymer on-line enrichment

A novel and simple chemiluminescence (CL) method has been developed and validated for determination of metformin. This method is based on hydroxyl radical chemiluminescence—the hydroxyl radical generated by reaction of Cu(II) and hydrogen peroxide oxidizes rhodamine B (RhB) to produce weak CL which can be enhanced by metformin. At the same time, metformin molecularly imprinted polymer (MIP) was synthesized. After enrichment based on the selectivity of metformin-MIP, the CL method was successfully applied to the determination of metformin in human serum. The linear range was from 1.0×10⁻⁸ to 1.0×10⁻⁶ g mL⁻¹ and the detection limit was 4×10⁻⁹ g mL⁻¹. The relative standard deviation at 2.0×10⁻⁷ g mL⁻¹ by use of MIP was 3.67% (n=7).     

High-energy ionising radiation initiated decomposition of acetovanillone

Hydroxyl radical, hydrated electron and hydrogen atom intermediates of water radiolysis react with acetovanillone with rate coefficients of (1.05±0.1)×10¹⁰, (3.5±0.5)×10⁹ and (1.7±0.2)×10¹⁰mol^?1 dm³ s^?1. Hydroxyl radical and hydrogen atom attach to the ring forming cyclohexadienyl type radicals. The hydroxyl–cyclohexadienyl radical formed in hydroxyl radical reaction in dissolved oxygen free solution partly transforms to phenoxyl radical. In the presence of O₂ phenoxyl radical formation and ring destruction are observed. Hydrated electron in O₂ free solution attaches to the carbonyl oxygen and undergoes protonation yielding benzyl type radical. In air saturated 0.5 mmol dm^?3 solution using 15 kGy dose most part of acetovanillone is degraded, for complete mineralisation five times higher dose is required. The experiments clearly show that acetovanillone can be efficiently removed from water by applying irradiation technology.     

Kinetic and mechanistic studies on the reaction of thiosemicarbazide with [(H<Subscript>2</Subscript>O)(tap)<Subscript>2</Subscript>RuORu(tap)<Subscript>2</Subscript>(H<Subscript>2</Subscript>O)]<Superscript>2+</Superscript> {tap = 2-(m-tolylazo)pyridine}

The interaction of thiosemicarbazide with the title complex has been studied spectrophotometrically in aqueous medium as a function of [complex], [thiosemicarbazide], pH and temperature at constant ionic strength. At pH 7.4, the reaction shows two distinct paths; both of which are [thiosemicarbazide] dependent. A parallel reaction scheme fits well with the experimental findings. An associative interchange mechanism is proposed for both the paths; the activation parameters calculated from Eyring plots are ΔH₁^≠ = 14.2 ± 0.8 kJ mol⁻¹, ΔS₁^≠ = −241 ± 2 JK⁻¹ mol⁻¹, ΔH₂^≠ = 30.8 ± 1.4 kJ mol⁻¹ and ΔS₂^≠ = −236 ± 4 JK⁻¹ mol⁻¹. From the temperature dependence of the outer sphere association complex equilibrium constants, the thermodynamic parameters calculated are ΔH₁^° = 34.25 ± 1.9 kJ mol⁻¹, ΔS₁^° = 146 ± 6 J K⁻¹ mol⁻¹ and ΔH₂^° = 9.4 ± 1.1 kJ mol⁻¹, ΔS₂^° = 71 ± 3 JK⁻¹ mol⁻¹, which gives a negative ΔG° at all temperatures studied, supporting the spontaneous formation of an outer sphere association complex.     

Application of ethyl chloroformate derivatization for solid-phase microextraction–gas chromatography–mass spectrometric determination of bisphenol-A in water and milk samples

A simple and rapid analytical method based on in-matrix ethyl chloroformate (ECF) derivatization has been developed for the quantitative determination of bisphenol-A (BPA) in milk and water samples. The samples containing BPA were derivatised with ECF in the presence of pyridine for 20 s at room temperature, and the non-polar derivative thus formed was extracted using polydimethylsiloxane solid-phase microextraction (SPME) fibres with thicknesses of 100 μm followed by analysis using gas chromatography–mass spectrometry. Three alkyl chloroformates (methyl, ethyl and isobutyl chloroformate) were tested for optimum derivatisation yields, and ECF has been found to be optimum for the derivatisation of BPA. Several parameters such as amount of ECF, pyridine and reaction time as well as SPME parameters were studied and optimised in the present work. The limit of detection for BPA in milk and water samples was found to be 0.1 and 0.01 μg L⁻¹, respectively, with a signal-to-noise ratio of 3:1. The limit of quantitation for BPA in milk and water was found to be 0.38 and 0.052 μg L⁻¹, respectively, with a signal-to-noise ratio of 10:1. In conclusion, the method developed was found to be rapid, reliable and cost-effective in comparison to silylation and highly suitable for the routine analysis of BPA by various food and environmental laboratories.     

Studies of the reaction of the hydroxyl radical with the oxalate ion in an acidic aqueous solution by pulse radiolysis

The reaction of the · OH radical with the oxalate ion in an acidic aqueous solution was studied by pulse radiolysis. The rate constant for the reaction of formation of the radical HOOC-COO·(λ_max = 250 nm, ɛ = 1800 L mol⁻¹ cm⁻¹) is (5.0±0.5)·107 L mol⁻¹ s⁻¹. In the reaction with the hydrogen ion (k = 1.1·10⁷ L mol⁻¹ s⁻¹), the radical HOOC-COO· is transformed into a nonidentified radical designated arbitrarily as H⁺(HOOC-COO)· (λ_max = 260 nm, ɛ = 4000 L mol⁻¹ cm⁻¹). Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1165–1167, June, 2008.     

Kinetics of reduction of hexavalent neptunium by nitrous acid in solutions of nitric acid

Nitrous acid is a key redox controlling factor, affecting the speciation of neptunium in the reprocessing of used nuclear fuel by solvent extraction. The kinetics of the reduction of neptunium(VI) by nitrous acid in solutions of nitric acid was investigated spectrophotometrically by the method of initial rates. The reaction is of first order with respect to Np(VI) while the order with respect to HNO₂ is 1.20 ± 0.04. The reaction rate is almost inversely proportional to the hydrogen ion concentration (reaction order −0.92 ± 0.06), indicating that the reaction proceeds primarily through the reaction of neptunium(VI) with the nitrate anion. The experimental value of the rate constant k for the rate law −d[Np(VI)]/dt = k·[Np(VI)]·[HNO₂]^1.2/[H⁺] is of (0.159 ± 0.014) M^−0.2 s⁻¹ in I = 4 M and at 20 °C. The activation energy is (−57.3 ± 1.6) kJ/mol, which is in agreement with previous data on this reaction in perchloric acid.     

Effect of electron-withdrawing power of the substituted group on?OH radical reaction with substituted aryl sulphides: A pulse radiolysis study

In neutral aqueous solution of (phenylthio)acetic acid, hydroxyl radical is observed to react with a bimolecular rate constant of 7.2 × 10^-1 dm³ mol⁻s⁻ and the transient absorption bands are assigned to^•OH radical addition to benzene and sulphur with a rough estimated values of 50 and 40% respectively. The reaction of the^•OH radical with diphenyl sulphide (k = 4.3 × 10⁸ dm³ mol⁻¹ s⁻¹) is observed to take place with formation of solute radical cation, OH-adduct at sulphur and benzene with estimated values of about 12, 28 and 60% respectively. The transient absorption bands observed on reaction of^•OH radical, in neutral aqueous solution of 4-(methylthio)phenyl acetic acid, are assigned to solute radical cation (λ_max = 550 and 730 nm), OH-adduct at sulphur (λ_max = 360 nm) and addition at benzene ring (λ_max = 320 nm). The fraction of^•OH radical reacting to form solute radical cation is observed to depend on the electron-withdrawing power of substituted group. In acidic solutions, depending on the concentration of acid and electron-withdrawing power, solute radical cation is the only transient species formed on reaction of^•OH radical with the sulphides studied.     

Photoinduced electron transfer reactions in the 10-methylacridinium cation–benzyltrimethylsilane system: steady-state and flash photolysis studies

The mechanism of the photoinduced reaction of the lowest excited singlet state of the 10-methylacridinium (AcrMe⁺) cation with benzyltrimethylsilane (BTMSi) in acetonitrile has been investigated by means of steady-state and time-resolved methods. A variety of stable products was found after irradiation (365 nm) of the reaction mixture under aerobic and oxygen-free conditions. The stable products were identified and analyzed using UV–Vis spectrophotometry, high performance liquid chromatography (HPLC), and mass spectrometry (MS). Based on Stern–Volmer plots of the AcrMe⁺ fluorescence quenching by BTMSi (using fluorescence intensity and lifetime measurements), the rate constants were determined to be k _q = 1.24 (± 0.02) × 10¹⁰ M⁻¹ s⁻¹ and k _q = 1.23 (± 0.02) × 10¹⁰ M⁻¹ s⁻¹, i.e., close to the diffusion-controlled limit in acetonitrile, indicating the dynamic quenching mechanism. The quenching process was shown to occur via an electron-transfer reaction leading to the formation of acridinyl radicals (AcrMe^•) and C₆H₅CH₂Si(CH₃)₃ ^•+ radical cations. Based on stationary and flash photolysis experiments, a detailed mechanism of the secondary reactions is proposed and discussed. The AcrMe^• radical was shown to decay by two processes. The fast decay, observed on the nanosecond timescale, was attributed to the back-electron transfer occurring within the initial radical ion pair. The slow decay on the microsecond timescale was explained by recombination reactions of radicals which escaped from the radical pair, including benzyl radicals formed via C–Si bond cleavage in the C₆H₅CH₂Si(CH₃)₃ ^•+ radical cation.     

A kinetic investigation of the oxidation of <Emphasis Type="SmallCaps">dl</Emphasis>-pipecolinate by bis(hydrogenperiodato)argentate(III) complex anion

Kinetics of oxidation of dl-pipecolinate by bis(hydrogenperiodato)argentate(III) complex anion, [Ag(HIO₆)₂]⁵⁻, has been studied in aqueous alkaline medium in the temperature range of 25–40 °C. The oxidation kinetics is first order in the silver(III) and pipecolinate concentrations. The observed second-order rate constant, decreasing with increasing [periodate] is virtually independent of [OH⁻]. α-Aminoadipate as the major oxidation product of pipecolinate has been identified by chromatographic analysis. A reaction mechanism is proposed that involves a pre-equilibrium between [Ag(HIO₆)₂]⁵⁻ and [Ag(HIO₆)(H₂O)(OH)]²⁻, a mono-periodate coordinated silver(III) complex. Both Ag(III) complexes are reduced in parallel by pipecolinate in rate-determining steps (described by k ₁ for the former Ag(III) species and k ₂ for the latter). The determined rate constants and their associated activation parameters are k ₁ (25 °C) = 0.40 ± 0.02 M⁻¹ s⁻¹, ∆H ₁^≠ = 53 ± 2 kJ mol⁻¹, ∆S ₁^≠ = −74 ± 5 J K⁻¹ mol⁻¹ and k ₂ (25 °C) = 0.64 ± 0.02 M⁻¹ s⁻¹, ∆H ₂^≠ = 41 ± 2 kJ mol⁻¹, ∆S ₂^≠ = −110 ± 5 J K⁻¹ mol⁻¹. The time-resolved spectra, a positive dependence of the rate constants on ionic strength of the reaction medium, and the consistency of pre-equilibrium constants derived from different reaction systems support the proposed reaction mechanism.     

Determination of dissociation energies of N-H bond in the 4-anilinodiphenylaminyl radical and O-H bond in the 2,5-dichloro-4-hydroxyphenoxyl radical from the equilibrium constants of chain reactions in quinoneimine-hydroquinone systems

The temperature dependences of the equilibrium constants of two chain reversible reactions in quinonediimine (quinonemonoimine)—2,5-dichlorohydroquinone systems in chlorobenzene were studied. The enthalpy of equilibrium of the reversible reaction of quinonediimine with 4-hydroxydiphenylamine was estimated from these data (ΔH = − 14.4±1.6 kJ mol⁻¹) and a more accurate value of the N-H bond dissociation energy in the 4-anilinodiphenylaminyl radical was determined (D _NH = 278.6±3.0 kJ mol⁻¹). A chain mechanism was proposed for the reaction between quinonediimine and 2,5-dichlorohydroquinone, and the chain length was estimated (ν = 300 units) at room temperature. Processing of published data on the rate constant of the reaction of styrylperoxy radicals with 2,5-dichlorohydroquinone in the framework of the intersecting parabolas method gave the O-H bond dissociation energy in 2,5-dichlorohydroquinone: D _OH = 362.4±0.9 kJ mol⁻¹. Taking into account these data, the O-H bond dissociation energy in the 2,5-dichlorosemiquinone radical was found: D _OH = 253.6±1.9 kJ mol⁻¹. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1661–1666, October, 2006.     

Determination of enzyme activity inhibition by FTIR spectroscopy on the example of fructose bisphosphatase

A mid-infrared enzymatic assay for label-free monitoring of the enzymatic reaction of fructose-1,6-bisphosphatase with fructose 1,6-bisphosphate has been proposed. The whole procedure was done in an automated way operating in the stopped flow mode by incorporating a temperature-controlled flow cell in a sequential injection manifold. Fourier transform infrared difference spectra were evaluated for kinetic parameters, like the Michaelis–Menten constant (K _M) of the enzyme and V _max of the reaction. The obtained K _M of the reaction was 14 ± 3 g L⁻¹ (41 μM). Furthermore, inhibition by adenosine 5′-monophosphate (AMP) was evaluated, and the K _M^App value was determined to be 12 ± 2 g L⁻¹ (35 μM) for 7.5 and 15 μM AMP, respectively, with V _max decreasing from 0.1 ± 0.03 to 0.05 ± 0.01 g L⁻¹ min⁻¹. Therefore, AMP exerted a non-competitive inhibition.     

Ab initio study on alkyl radical decomposition and alkyl radical addition to olefins

The β bond dissociation of alkyl radicals and their reverse reactions, the addition of alkyl radicals to olefins were studied by G3MP2 level of theory to obtain a consistent kinetic data set. Both reaction families can be classified depending on the type of radical formed by β bond scission, namely the CH₃, primary, secondary tertiary radical formed. The kinetics of the reaction classes were described by only a limited number of Arrhenius parameters. The unified A factor of 10^13.7 s⁻¹ was found for all β bond dissociations. The Arrhenius activation energies are 125, 121, 113 and 103 kJ mol⁻¹, for methyl, primary, secondary, and tertiary radicals, respectively. The activation energies of 32, 25 and 18 kJ mol⁻¹ are calculated for the terminal addition of primary (including methyl), secondary, and tertiary radicals to olefins, respectively. The biologically important nonterminal radical additions to olefins have higher barriers of 37, 31 and 35 kJ mol⁻¹, respectively. At room temperature both strongly exothermic additions can compete with H-atom abstraction. New groups for Benson’s group additivity rules were defined to describe activation parameters for the β bond dissociation reactions. The group values were calculated by using the ab initio heats of formation of transition state structures.     

Study of natural radionuclides in Karun river region

In this study the concentration of natural radionuclides has been investigated in soil and water of Karun river by using a high resolution (HPGe detector, n-type) γ-spectrometry. The concentrations range in water sample was 47.6 ± 5.6–130.8 ± 6.3, 0.0–23.4 ± 0.5 and 0–6.4 ± 2.0 Bq L⁻¹ for ⁴⁰K, ²³²Th and ²²⁶Ra respectively. For soil samples the concentration range of 275.7 ± 8.6–458.6 ± 6.8, 19.2 ± 5.35–41.1 ± 3.95 and 29.9 ± 1.53–50 ± 1.54 Bq kg⁻¹ was obtained respectively for ⁴⁰K, ²³²Th and ²³⁸U. ¹³⁷Cs was also detected in some part of the region in soil samples. The mean concentration of ¹³⁷Cs was 5.5 ± 0.6 Bq kg⁻¹. The origin of this activity is unknown. The average absorbed dose rate in outdoor air at a height of 1 m above the ground was found to be 54.3 ± 3.7 nGy h⁻¹. The results of this study indicate that the area has standard background radiation level.     

Ultra low level deep water <Superscript>137</Superscript>Cs activity in the South Pacific Ocean

We determined ¹³⁷Cs concentrations in deep water samples of the subtropical gyre in the South Pacific collected during the BEAGLE2003 cruise. This was done at an underground facility to achieve extremely low background γ-spectrometry, and we, therefore, obtained reliable values of ¹³⁷Cs activity in the deeper layers. ¹³⁷Cs activity in the layers between 2000 and 4500 m ranged from 7 ± 4 mBq m⁻³ to 25 ± 11 mBq m⁻³. The inventory of ¹³⁷Cs in the water column from 2000 m to the sea bottom was estimated to be 20 ± 8 Bq m⁻² to 94 ± 41 Bq m⁻² in this region.     

Application of inductively coupled plasma–mass spectrometry (ICP–MS) and quality assurance to study the incorporation of strontium into bone,bone marrow,and teeth of dogs after one month of treatment with strontium malonate

The strontium content of serum, bone, marrow, and teeth was determined by inductively-coupled plasma mass spectrometry (ICP–MS). Significant correlations were obtained after the data were subjected to quality assurance (QA) performed according to validated procedures. After four weeks of treatment with strontium malonate, strontium levels increased from 76 ± 9 μg g⁻¹ in placebo-treated dogs to levels of 7.2 ± 1.7 mg g⁻¹, 9.5 ± 2.7 mg g⁻¹, and 9.8 ± 2.7 mg g⁻¹ in groups treated with 300, 1000, and 3000 mg kg⁻¹ day⁻¹, respectively. Strontium induced a highly significant increase in the bone formation marker, bone-specific alkaline phosphatase (BSAP), and an excellent correlation was found with the bone-strontium content. In females, the placebo-treated group showed a decrease in BSAP of 53%, whereas the three strontium malonate-treated groups showed an increase of 60, 276, and 278% for the groups treated with 300, 1000, and 3000 mg kg⁻¹ day⁻¹, respectively. For males the corresponding values were −44%, +142%, +194%, and +247% increases in BSAP in the placebo, 300, 1000, and 3000 mg kg⁻¹ day⁻¹ groups respectively.