From Selection to Instruction and Back: Competing Conformational Selection and Induced Fit Pathways in Abiotic Hosts.

Two limiting cases of molecular recognition, induced fit (IF) and conformational selection (CS), play a central role in allosteric regulation of natural systems. The IF paradigm states that a substrate "instructs" the host to change its shape after complexation, while CS asserts that a guest "selects" the optimal fit from an ensemble of preexisting host conformations. With no studies that quantitatively address the interplay of two limiting pathways in abiotic systems, we herein and for the first time describe the way by which twisted capsule M-1, encompassing two conformers M-1(+) and M-1(-), trap CX4 (X=Cl, Br) to give CX4 ⊂M-1(+) and CX4 ⊂M-1(-), with all four states being in thermal equilibrium. With the assistance of 2D EXSY, we found that CBr4 would, at its lower concentrations, bind M-1 via a M-1(+)→M-1(-)→CBr4 ⊂M-1(-) pathway corresponding to conformational selection. For M-1 complexing CCl4 though, data from 2D EXSY measurements and 1D NMR line-shape analysis suggested that lower CCl4 concentrations would favor CS while the IF pathway prevailed at higher proportions of the guest. Since CS and IF are not mutually exclusive, we reason that our work sets the stage for characterizing the dynamics of a wide range of already existing hosts to broaden our fundamental understanding of their action. The objective is to master the way in which encapsulation takes place for designing novel and allosteric sequestering agents, catalysts and chemosensors akin to those found in nature.

Hepatoprotective Activity of Linalool in Rats Against Liver Injury Induced by Carbon Tetrachloride.

This study aimed to investigate and compare hepatoprotective activity of Coriandrum sativum (Cs) and it is major component linalool (Ln) against experimentally induced hepatotoxicity in rats. Essential oil of Cs was isolated by hydrodistillation method and chemical composition was determined by GS-MS analysis. 42 male Wistar Albino rats were divited into 7 groups each containing 6. The experimental groups were designed as: Normal control group, 1 ml/kg CCl4 administirated group, 25 mg/kg Silymarin and CCl4 administirated group, 100 and 200 mg/kg Cs and CCl4 administirated groups, 100 and 200 mg/kg Ln and CCl4 administered groups. The protective activities were determined according to the results of liver biomarkers (AST, ALT, ALP), antioxidant parameters (GSH, GPx, CAT), lipid peroxidation (MDA) and histopathological examination. Linalool percentage of Cs was 81.6%. The groups treated with linalool (100 and 200 mg/kg) (p < 0.01) and coriander (200 mg/kg) (p < 0.05) had significantly reduced AST (262-375) and ALT (101-290) levels (U/L) compared to the CCl4 (600-622) group. The levels (nmol/g protein) of MDA (11-12) were significantly lower (p < 0.01), the levels of GSH (11-12) and the activities of CAT (23-24) were significantly higher (p < 0.01) in linalool groups (100 and 200 mg/kg) compared to the CCl4 (18-5-10 respectively) group. These results were also supported by histopathological findings and indicate that Cs and Ln shows hepatoprotective activity against liver damage. In this regard, evaluation of activities of major components are needed to compare to medicinal plants in experimental diseases models.

Hepatoprotective effects of Psidium guajava on mitochondrial enzymes and inflammatory markers in carbon tetrachloride-induced hepatotoxicity.

OBJECTIVE: The present investigation was aimed to evaluate the hepatoprotective potential of ethanolic extract of Psidium guajava (P. guajva) and its isolated quercetin fraction on carbon tetrachloride (CCl4)-induced hepatotoxicity. MATERIALS AND METHODS: The rats were divided into 6 groups and each group contained 6 rats. CCl4 (1.5 ml/kg b.w.) was used to induce the hepatotoxicity. Ethanolic extract of P. guajava (300 mg/kg b.w.), isolated quercetin fraction (20 mg/kg b.w.) were used as a treatment and silymarin (25 mg/kg b.w.) was used as a standard drug. After the study period, the liver tissues were collected and evaluate the levels of liver functional markers, mitochondrial enzymes, histopathological analysis and the expressions of inflammatory markers. RESULTS: The levels of liver functional markers were increased and protein, albumin and A/G ratio levels were decreased and the decreased levels of mitochondrial enzymes were noted in CCl4-induced rats and the levels were restored near to normal significantly when the administration ethanolic extract of P. guajava, isolated quercetin fraction and silymarin. The normal architecture of liver tissues were altered and the mRNA expressions were up-regulated in CCl4-induced rats and the liver tissues were normalized and the mRNA and protein expressions were down-regulated near to normal significantly when the administration of ethanolic extract of P. guajava, isolated quercetin fraction and silymarin. CONCLUSION: From these results, the isolated quercetin fractions have better activity than that of the ethanolic extract of P. guajava leaves. Hence, the isolated quercetin may be used as the safest drug for hepatotoxicity in future.

CCl4-Enhanced Ultrasonic Irradiation for Ciprofloxacin Degradation and Antibiotic Activity.

In this study, an ultrasound/CCl4 system was used to degrade the fluoroquinolone antibiotic, ciprofloxacin, in aqueous solution. The effect of CCl4 concentration and initial solution pH on ciprofloxacin degradation were investigated. The results showed that ciprofloxacin degraded effectively under an ultrasound/CCl4 system, with degradation efficiency increasing from 0.51% to 50.92%, when the CCl4 concentration ranged from 0.0 to 41.4 mmol/L in 40 min. Radical scavenging experiments certified that both •OH and chlorine-containing radicals contributed to ciprofloxacin degradation. Eight intermediates were detected using ultra high-performance liquid chromatography-mass spectrometry (UHPLC-MS) method, including three chloro-intermediates. Based on these results, the possible degradation pathways of ciprofloxacin are proposed. Agar diffusion tests with E. coli and S. aureus showed that ciprofloxacin's antibacterial activity was completely removed in 40 min. This study indicates that an ultrasound/CCl4 system can degrade ciprofloxacin and remove its antibacterial activity, and thus is a promising process for treating fluoroquinolone antibiotics in wastewater.

KOtBu as a Single Electron Donor? Revisiting the Halogenation of Alkanes with CBr4 and CCl4.

The search for reactions where KOtBu and other tert-alkoxides might behave as single electron donors led us to explore their reactions with tetrahalomethanes, CX4, in the presence of adamantane. We recently reported the halogenation of adamantane under these conditions. These reactions appeared to mirror the analogous known reaction of NaOH with CBr4 under phase-transfer conditions, where initiation features single electron transfer from a hydroxide ion to CBr4. We now report evidence from experimental and computational studies that KOtBu and other alkoxide reagents do not go through an analogous electron transfer. Rather, the alkoxides form hypohalites upon reacting with CBr4 or CCl4, and homolytic decomposition of appropriate hypohalites initiates the halogenation of adamantane.

Extracorporeal Barbotage Detoxification of the Blood Plasma.

We studied the efficiency of bubbling air as a method of detoxification of the blood plasma and its mixtures with plasma substitutes from CCl4. The efficiency of detoxification depended on the characteristics of the obtained foams: foam forming ability, frequency rate, dispersion, stability of a foam skeleton, syneresis, etc. A hardware-software complex for extracorporeal blood plasma detoxification was developed and the programs for the control and regulation of this process were tested. Physical and mathematical models of toxicant excretion from the body during extracorporal blood detoxification were proposed. Verification of the mathematical model demonstrates high correspondence between the theoretical and experimental data.

Amino Acid-Assisted Dehalogenation of Carbon Tetrachloride by Green Rust: Inhibition of Chloroform Production.

Layered FeII-FeIII hydroxides (green rusts, GRs) are promising reactants for reductive dechlorination of chlorinated solvents due to high reaction rates and the opportunity to inject reactive slurries of the compounds into contaminant plumes. However, it is necessary to develop strategies that reduce the formation of toxic byproducts such as chloroform (CF). In this study, carbon tetrachloride (CT) dehalogenation by the chloride form of GR (GRCl) was tested in the presence of glycine (GLY) and other selected amino acids. GLY, alanine (ALA), and serine (SER) all resulted in remarkable suppression of CF formation with only ∼10% of CF recovery while sarcosine (SAR) showed insignificant effects. For two nonamino acid buffers, TRIS had little effect while HEPES resulted in a 40 times lower rate constant compared to experiments in which no buffer was added. The FeII complexing properties of the amino acids and buffers caused variable extents of GRCl dissolution which was linearly correlated with CF suppression and dehalogenation rate. We hypothesize that the CF suppression seen for amino acids is caused by stabilization of carbene intermediates via the carbonyl group. Different effects on CF suppression and CT dehalogenation rate were expected because of the different structural and chemical properties of the amino acids.

Fabrication of bimetallic Ag/Fe immobilized on modified biochar for removal of carbon tetrachloride.

As an effective conventional absorbent, biochar exhibited limited adsorption ability toward small hydrophobic molecules. To enhance the adsorption capacity, a novel adsorbent was prepared by immobilizing nanoscale zero-valent iron onto modified biochar (MB) and then the elemental silver was attached to the surface of iron (Ag/Fe/MB). It's noted that spherical Ag/Fe nanoparticles with diameter of 51nm were highly dispersed on the surface of MB. As the typical hydrophobic contaminant, carbon tetrachloride was selected for examining the removal efficiency of the adsorbent. The removal efficiencies of carbon tetrachloride by original biochar (OB), Ag/Fe, Ag/Fe/OB and Ag/Fe/MB were fully investigated. It's found that Ag/Fe/MB showed higher carbon tetrachloride removal efficiency, which is about 5.5 times higher than that of the OB sample due to utilizing the merits of high adsorption and reduction. Thermodynamic parameters revealed that the removal of carbon tetrachloride by Ag/Fe/MB was a spontaneous and exothermic process, which was affected by solution pH, initial carbon tetrachloride concentration and temperature. The novel Ag/Fe/MB composites provided a promising material for carbon tetrachloride removal from effluent.

Assessment of liver fibrosis in rats by MRI with apparent diffusion coefficient and T1 relaxation time in the rotating frame.

PURPOSE: To explore the value of T1 relaxation times in the rotating frame (T1 ρ or T1 rho) for evaluating liver fibrosis stage, compared to apparent diffusion coefficients (ADCs). MATERIALS AND METHODS: Liver fibrosis in model rats (n = 50) was produced by carbon tetrachloride (CCl4 ) injection. Five rats died during the experiment. Surviving model rats (n = 45) and controls (n = 15) were subjected to 3.0T MRI and the ADCs (b-values: 0, 800 s/mm(2) ) and T1 ρ values were determined. Liver fibrosis stage (F0-F4) was defined based on METAVIR scoring. Nonparametric statistical methods and receiver operating characteristic (ROC) curve analyses were employed to determine diagnostic accuracy. RESULTS: Mean ADC and T1 ρ associated negatively (r = -0.732 P < 0.001) and positively (r = 0.863 P < 0.001), respectively, with severity of fibrosis stage. Analysis of ROC curves for fibrosis staging showed that the area under the curve (AUC) for T1 ρ (stage F0 vs. F1-F4 = 0.976, stage F0-F1 vs. F2-F4 = 0.920, stage F0-F2 vs. F3-F4 = 0.938, and stage F0-F3 vs. F4 = 0.931) was larger than that for ADCs (0.917, 0.924, 0.842, and 0.781, respectively). CONCLUSION: ADC and T1 ρ values correlate with liver fibrosis stage. The performance of the T1 ρ parameter was superior to that of the ADC parameter in the differentiation of liver fibrosis stages in a CCl4 rat model.

Assessment of liver fibrosis by variable flip angle T1 mapping at 3.0T.

PURPOSE: To evaluate the possibility of using a variable flip angle (VFA) T1 mapping technique to diagnose liver fibrosis. MATERIALS AND METHODS: Liver fibrosis was induced in rabbits by repetitive administration of carbon tetrachloride (CCl4 ). T1 -weighted magnetic resonance imaging (MRI) was performed in 29 animals (liver fibrosis, n = 18; control, n = 11) using a series of nonenhanced liver acquisition volume acceleration (LAVA) with VFAs at 3.0T. Hepatic T1 relaxation times were measured via regions of interest, which were correlated with subsequent histologic confirmation. The results of T1 mapping in assessment of liver fibrosis were compared with that of apparent diffusion coefficient (ADC) values. RESULTS: The mean T1 relaxation time of the control group was the lowest (250.07 ± 88.12 msec), followed by the nonadvanced fibrosis group (387.83 ± 166.58 msec) and the advanced fibrosis group (496.90 ± 291.24 msec). T1 relaxation time measurements differed significantly between the liver fibrosis group and control group (P < 0.05), with a trend of increased mean T1 relaxation times as the fibrotic stage increased. Statistically significant differences were observed between the control group and the nonadvanced fibrosis group (P < 0.05), however with much overlap between the less severe stages. In discriminating between the control group and liver fibrosis group, stage F0-1 (control and stage F1) and stage F2-3, stage F0-2 (control and stage F1-2) and stage F3, area under the receiver operating characteristic (ROC) curves were 0.803 (cutoff value 273.01 msec), 0.712 (cutoff value 371.54 msec), and 0.696 (cutoff value 276.99 msec), respectively. No difference was found between T1 relaxation times and ADC values in assessment of liver fibrosis in our study. CONCLUSION: VFA T1 mapping may become a noninvasive imaging tool for the diagnosis of liver fibrosis.

Iron-Sulfide-Associated Products Formed during Reductive Dechlorination of Carbon Tetrachloride.

This paper investigated the mackinawite (FeS)-associated products formed during reaction between FeS and carbon tetrachloride (CT) at pH 7 and 8. At pH 8, reaction of FeS with CT led to formation of abundant spherical particles with diameters between 50 and 400 nm on the FeS surface and in solution; far fewer such particles were observed at pH 7. Analysis of the FeS surface by energy dispersive X-ray spectroscopy after reaction with CT at pH 8 showed decreased sulfur and elevated oxygen compared to unreacted FeS. The spherical particles that formed upon FeS reaction with CT were mostly amorphous with localized areas of poorly crystalline two-line ferrihydrite. X-ray photoelectron spectroscopy indicated that the predominant Fe surface species after reaction with CT at pH 8 was Fe(III)-O, consistent with ferrihydrite and other amorphous iron (hydr)oxides as major products. Powder X-ray diffraction analysis suggested formation of greigite upon reaction of FeS with CT at pH 7. Both ferrihydrite and Fe(2+), which is a product of greigite dissolution, can react with dissolved HS(-) to form FeS, suggesting that, after oxidation by chlorinated aliphatics, FeS can be regenerated by addition or microbial generation of sulfide.

Chemical Reactivity Probes for Assessing Abiotic Natural Attenuation by Reducing Iron Minerals.

Increasing recognition that abiotic natural attenuation (NA) of chlorinated solvents can be important has created demand for improved methods to characterize the redox properties of the aquifer materials that are responsible for abiotic NA. This study explores one promising approach: using chemical reactivity probes (CRPs) to characterize the thermodynamic and kinetic aspects of contaminant reduction by reducing iron minerals. Assays of thermodynamic CRPs were developed to determine the reduction potentials (ECRP) of suspended minerals by spectrophotometric determination of equilibrium CRP speciation and calculations using the Nernst equation. ECRP varied as expected with mineral type, mineral loading, and Fe(II) concentration. Comparison of ECRP with reduction potentials measured potentiometrically using a Pt electrode (EPt) showed that ECRP was 100-150 mV more negative than EPt. When EPt was measured with small additions of CRPs, the systematic difference between EPt and ECRP was eliminated, suggesting that these CRPs are effective mediators of electron transfer between mineral and electrode surfaces. Model contaminants (4-chloronitrobenzene, 2-chloroacetophenone, and carbon tetrachloride) were used as kinetic CRPs. The reduction rate constants of kinetic CRPs correlated well with the ECRP for mineral suspensions. Using the rate constants compiled from literature for contaminants and relative mineral reduction potentials based on ECRP measurements, qualitatively consistent trends were obtained, suggesting that CRP-based assays may be useful for estimating abiotic NA rates of contaminants in groundwater.

Vibrational circular dichroism and theoretical study of the conformational equilibrium in (-)-S-nicotine.

We report an extensive study of the molecular and electronic structure of (-)-S-nicotine, to deduce the phenomenon that controls its conformational equilibrium and to solve its solution-state conformer population. Density functional theory, ab initio, and molecular mechanics calculations were used together with vibrational circular dichroism (VCD) and Fourier transform infrared spectroscopies. Calculations and experiments in solution show that the structure and the conformational energy profile of (-)-S-nicotine are not strongly dependent on the medium, thus suggesting that the conformational equilibrium is dominated by hyperconjugative interactions rather than repulsive electronic effects. The analysis of the first recorded VCD spectra of (-)-S-nicotine confirmed the presence of two main conformers at room temperature. Our results provide further evidence of the hypersensitivity of vibrational optical activity spectroscopies to the three-dimensional structure of chiral samples and prove their suitability for the elucidation of solution-state conformer distribution.

The use of alkaline hydrolysis as a novel strategy for chloroform remediation: the feasibility of using construction wastes and evaluation of carbon isotopic fractionation.

Laboratory and field-scale pilot experiments were performed to evaluate the feasibility of chloroform degradation by alkaline hydrolysis and the potential of δ(13)C values to assess this induced reaction process at contaminated sites. In batch experiments, alkaline conditions were induced by adding crushed concrete (pH 12.33 ± 0.07), a filtered concrete solution (pH 12.27 ± 0.04), a filtered cement solution (pH 12.66 ± 0.02) and a pH 12 buffer solution (pH 11.92 ± 0.11). The resulting chloroform degradation after 28 days was 94, 96, 99, and 72%, respectively. The experimental data were described using a pseudo-first-order kinetic model, resulting in pseudo-first-order rate constant values of 0.10, 0.12, 0.20, and 0.05 d(-1), respectively. Furthermore, the significant chloroform carbon isotopic fractionation associated with alkaline hydrolysis of chloroform (-53 ± 3‰) and its independence from pH in the admittedly limited tested pH range imply a great potential for the use of δ(13)C values for in situ monitoring of the efficacy of remediation approaches based on alkaline hydrolysis. The carbon isotopic fractionation obtained at the lab scale allowed the calculation of the percentage of chloroform degradation in field-scale pilot experiments where alkaline conditions were induced in two recharge water interception trenches filled with concrete-based construction wastes. A maximum of approximately 30-40% of chloroform degradation was achieved during the two studied recharge periods. Although further research is required, the treatment of chloroform in groundwater through the use of concrete-based construction wastes is proposed. This strategy would also imply the recycling of construction and demolition wastes for use in value-added applications to increase economic and environmental benefits.

Influence of riboflavin on nanoscale zero-valent iron reactivity during the degradation of carbon tetrachloride.

Experiments were conducted to investigate the effect of riboflavin on the reactivity of nanoscale zerovalent iron (NZVI) during three reaction cycles of carbon tetrachloride (CT) degradation. The degradation kinetics of CT by NZVI without riboflavin (0.556 ± 0.044 h(-1)) was 1.5 times higher than that with riboflavin (0.370 ± 0.012 h(-1)) in the first cycle. Riboflavin was rapidly reduced (65.0 ± 7.0 h(-1)) by NZVI during CT degradation, resulting in the slow degradation kinetics of CT in the first cycle due to competition for electrons from NZVI between riboflavin and CT. These results indicate that riboflavin is not effective as an electron shuttle for reduction of CT by NZVI. On the other hand, the degradation kinetics of CT by NZVI without riboflavin decreased to 0.122 ± 0.033 h(-1) in the third cycle, while that with riboflavin was significantly enhanced (0.663 ± 0.005 h(-1)). The results from X-ray analyses and transmission electron microscopy suggest that the decline in reactivity of NZVI without riboflavin in the third cycle resulted from continuous Fe(0) oxidation to iron oxides on the NZVI surface. In contrast, riboflavin enhanced the reactivity of NZVI by reductive dissolution of passive iron oxides on NZVI surface by reduced riboflavin. The experimental results suggest that riboflavin can play a pivotal role in the prolongation of NZVI reactivity in long-term in situ and ex situ applications of NZVI.

Density functional theory study of the oligomerization of carboxylic acids.

We present a density functional theory [M06-2X/6-31+G(d,p)] study of the structures and free energies of formation of oligomers of four carboxylic acids (formic acid, acetic acid, tetrolic acid, and benzoic acid) in water, chloroform, and carbon tetrachloride. Solvation effects were treated using the SMD continuum solvation model. The low-lying energy structures of molecular complexes were located by adopting an efficient search procedure to probe the potential energy surfaces of the oligomers of carboxylic acids (CA)n (n = 2-6). The free energies of the isomers of (CA)n in solution were determined as the sum of the electronic energy, vibrational-rotational-translational gas-phase contribution, and solvation free energy. The assessment of the computational protocol adopted in this study with respect to the dimerization of acetic acid, (AA)2, and formic acid, (FA)2, located new isomers of (AA)2 and (FA)2 and gave dimerization constants in good agreement with the experimental values. The calculation of the self-association of acetic acid, tetrolic acid, and benzoic acid shows the following: (i) Classic carboxylic dimers are the most stable isomer of (CA)2 in both the gas phase and solution. (ii) Trimers of carboxylic acid are stable in apolar aprotic solvents. (iii) Molecular clusters consisting of two interacting classic carboxylic dimers (CA)4,(D+D) are the most stable type of tetramers, but their formation from the self-association of classic carboxylic dimers is highly unfavorable. (iv) For acetic acid and tetrolic acid the reactions (CA)2 + 2CA → (CA)4,(D+D) and (CA)3 + CA → (CA)4,(D+D) are exoergonic, but these aggregation pathways go through unstable clusters that could hinder the formation of tetrameric species. (v) For tetrolic acid the prenucleation species that are more likely to form in solution are dimeric and trimeric structures that have encoded structural motifs resembling the α and ß solid forms of tetrolic acid. (vi) Stable tetramers of benzoic acid could form in carbon tetrachloride from the aggregation of trimers and monomers. (vii) Higher order clusters such as acetic acid pentamers and tetrolic acid hexamers are highly unstable in all solvation environments.

A recipe for free-energy functionals of polarizable molecular fluids.

Classical density-functional theory is the most direct approach to equilibrium structures and free energies of inhomogeneous liquids, but requires the construction of an approximate free-energy functional for each liquid of interest. We present a general recipe for constructing functionals for small-molecular liquids based only on bulk experimental properties and ab initio calculations of a single solvent molecule. This recipe combines the exact free energy of the non-interacting system with fundamental measure theory for the repulsive contribution and a weighted density functional for the short-ranged attractive interactions. We add to these ingredients a weighted polarization functional for the long-range correlations in both the rotational and molecular-polarizability contributions to the dielectric response. We also perform molecular dynamics calculations for the free energy of cavity formation and the high-field dielectric response, and show that our free-energy functional adequately describes these properties (which are key for accurate solvation calculations) for all three solvents in our study: water, chloroform, and carbon tetrachloride.

Weighted-density functionals for cavity formation and dispersion energies in continuum solvation models.

Continuum solvation models enable efficient first principles calculations of chemical reactions in solution, but require extensive parametrization and fitting for each solvent and class of solute systems. Here, we examine the assumptions of continuum solvation models in detail and replace empirical terms with physical models in order to construct a minimally-empirical solvation model. Specifically, we derive solvent radii from the nonlocal dielectric response of the solvent from ab initio calculations, construct a closed-form and parameter-free weighted-density approximation for the free energy of the cavity formation, and employ a pair-potential approximation for the dispersion energy. We show that the resulting model with a single solvent-independent parameter: the electron density threshold (nc), and a single solvent-dependent parameter: the dispersion scale factor (s6), reproduces solvation energies of organic molecules in water, chloroform, and carbon tetrachloride with RMS errors of 1.1, 0.6 and 0.5 kcal/mol, respectively. We additionally show that fitting the solvent-dependent s6 parameter to the solvation energy of a single non-polar molecule does not substantially increase these errors. Parametrization of this model for other solvents, therefore, requires minimal effort and is possible without extensive databases of experimental solvation free energies.

Fe(II) coordination transition regulates reductive dechlorination: The overlooked abiotic role of lactate.

The coordination environment of Fe(II) significantly affect the reductive reactivity of Fe(II). Lactate is a common substrate for enhancing microbial dechlorination, but its effect on abiotic Fe(II)-driven reductive dechlorination is largely ignored. In this study, the structure-reactivity relationship of Fe(II) is investigated by regulating the ratio of lactate:Fe(II). This work shows that lactate-Fe(II) complexing enhances the abiotic Fe(II)-driven reductive dechlorination with the optimum lactate:Fe(II) ratio of 10:20. The formed hydrogen bond (Fe-OH∙∙∙∙∙∙O = C-) and Fe-O-C metal-ligand bond result in a reduced Fe(II) coordination number from six to four, which lead to the transition of Fe(II) coordination geometry from octahedron to tetrahedron/square planar. Coordinatively unsaturated Fe(II) results in the highest reductive dechlorination reactivity towards carbon tetrachloride (k1 = 0.26254 min-1). Excessive lactate concentration (> 10 mM) leads to an increased Fe(II) coordination number from four to six with a decreased reductive reactivity. Electrochemical characterization and XPS results show that lactate-Fe(II)-I (C3H5O3-:Fe(II) = 10:20) has the highest electron-donating capacity. This study reveals the abiotic effect of lactate on reductive dechlorination in a subsurface-reducing environment where Fe(II) is usually abundant.

Fullerene crystals with bimodal pore architectures consisting of macropores and mesopores.

A new class of fullerene (C(60)) crystals with bimodal pore architectures consisting of macropores and mesopores was synthesized by using a liquid-liquid interfacial precipitation (LLIP) method involving an interface between isopropyl alcohol (IPA) and a saturated solution of C(60) in a mixture of benzene and carbon tetrachloride (CCl(4)). By varying the mixing fraction of CCl(4) in benzene, the porosity and electrochemically active surface area can be flexibly controlled.