Abatement of the ecotoxicological risk of landfill leachate by heterogeneous Fenton-like oxidation

Landfill leachates are highly contaminated liquid waste, and their treatment and detoxification are a challenging task. The current system of ecotoxicological risk assessment is complex and time-consuming. It is of fundamental importance to develop simpler and faster tools for the evaluation of the treated liquid waste and for an easier preliminary screening of the most active catalytic formulation/reaction conditions of the Fenton-like process. Here, several analytical techniques have been used for the assessment of the reduction of toxicity of the landfill leachate after Fenton process over copper-zirconia catalyst (ZrCu). Ultraviolet-visible (UV-vis) spectroscopy and absorbable organic halogens (AOX) analysis have been coupled to achieve further insight into the degradation of contaminants. In addition, for the first time, the qualitative abatement of organic compounds is monitored through proton nuclear magnetic resonance (¹H NMR) analysis, providing a new method for evaluating the effectiveness of the treatment. Spectroscopic techniques reveal that the Fenton process induces a significant abatement of the aromatic and halogen compounds (51%) in the landfill leachate with a reduction of the toxicity that has been confirmed by ecotoxicological test with algae. These results validate the investigated tool for a simple rapid preliminary evaluation of the detoxification efficacy.

Imprinting Pentaphyrin on Conductive Electropolymerized Dipyrromethane Films: A New Strategy towards the Synthesis of Photokilling Materials

We report herein the synthesis and photoinduced bactericidal activity of two new polymeric materials, obtained by imprinting the photosensitizer 20-(4-carboxyphenyl)-2,13-dimethyl-3,12-diethyl-[22]pentaphyrin (PCox, 1) into suitable electropolymerized dipyrromethane films. 5-Phenyl-dipyrromethane (5-ph-DP) and 5-(4-pyridyl)dipyrromethane (5-py-DP) have been selected as the monomers for the synthesis of the materials in order to assess the correlation between the substituent in C5 and the capability in Pcox uptake. Both films have been tested in their photokilling ability toward Staphylococcus aureus by using a multi-LED blue lamp at a fluence rate of 40 W/m² . Poly-5-py-DP/PCox, with a PCox load of 10^-8  mol/cm² , achieved a 4-log reduction in microbial viability after 60 min of irradiation. The polymeric films proved to be stable over time and under oxidation conditions; in addition, no loss of photosensitizer was observed during the experiments, thus demonstrating that the bactericidal action was effectively brought by the ROS generated by PCox immobilized in the material. After use, the films were recharged with PCox, with almost complete recovery of their photodynamic efficiency.

CNN pincer ruthenium complexes for efficient transfer hydrogenation of biomass-derived carbonyl compounds

The ligand HCNNOMe (6-(4-methoxyphenyl)-2-aminomethylpyridine) is easily prepared from the commercially available 6-(4-methoxyphenyl)pyridine-2-carbaldehyde by the reaction of hydroxylamine and hydrogenation (H2, 1 atm) with Pd/C. The pincer complexes cis-[RuCl(CNNOMe)(PPh3)2] (1) and [RuCl(CNNOMe)(PP)] (PP = dppb, 2; and dppf, 3) are synthesized from [RuCl2(PPh3)3], HCNNOMe and PP (for 2 and 3) in 2-propanol with NEt3 at reflux and are isolated in 85-93% yield. Carbonylation of 1 (CO, 1 atm) gives [RuCl(CNNOMe)(CO)(PPh3)] (4) (79% yield) which cleanly reacts with Na[BArf4] and PCy3, affording the cationic trans-[Ru(CNNOMe)(CO)(PCy3)(PPh3)][BArf4] (5) (92% yield). These robust pincer complexes display remarkably high catalytic activity in the transfer hydrogenation (TH) of lignocellulosic biomass carbonyl compounds, using 2-propanol at reflux in a basic medium (NaOiPr or K2CO3). Thus, furfural, 5-(hydroxymethyl)furfural and Cyrene are reduced to the corresponding alcohols with 2 and 3, at S/C in the range of 10 000-100 000, within minutes or hours (TOF up to 1 500 000 h-1). The monocarbonyl complex 5 was found to be extremely active in the TH of cinnamaldehyde, vanillin derivatives and ethyl levulinate at S/C in the range of 10 000-50 000. Vanillyl alcohol is also obtained by the TH of vanillin with 5 (S/C = 500) in 2-propanol in the presence of K2CO3.

Preparation of monocarbonyl ruthenium complexes bearing bidentate nitrogen and phosphine ligands and their catalytic activity in carbonyl compound reduction

A series of novel monocarbonyl ruthenium catalysts containing bidentate dinitrogen or/and diphosphine ligands are easily obtained through a general and straightforward approach.

Biological evaluation of a Porphyrin-SPION nanoconjugate as an antimicrobial magnetic photosensitizer

The present work describes the use of a magnetic porphyin (5-(4-carboxy-phenyl)-10,15,20-triphenyl-21H, 23H-porphyrin TPP) nanoconjugate (SPION-TPP) for destroying pathogenic bacteria followed by the recovery of the magnetic photosensitizer. SPION-TPP was tested for its activity against two different gram-positive bacterial strains (Staphylococcus aureus and Steptoccoccus mutans). It is observed that SPION-TPP at a very low concentration of 0.5 [Formula: see text]M is effective in destroying gram-positive bacteria (10[Formula: see text]–10[Formula: see text] CFU ml[Formula: see text] S. aureus with several orders reduction and few orders in S. mutans. The aim of this work is to combine photoactivity against microorganisms imparted by the photosensitizer with the possibility of recovering the nanoconstruct with magnets for disposal/reuse.

5-Phenyl-dipyrromethane and 5-(4-pyridyl)-dipyrromethane as modular building blocks for bio-inspired conductive molecularly imprinted polymer (cMIP). An electrochemical and piezoelectric investigation

5-Phenyl-dipyrromethane (5-ph-DP) and 5-(4-pyridyl)dipyrromethane (5-py-DP) are proposed, for the first time, as electroactive building blocks for the preparation of sensors based on molecularly imprinted conductive polymers (cMIP).

SOLVERSTAT: a new utility for multipurpose analysis. An application to the investigation of dioxygenated Co(II) complex formation in dimethylsulfoxide solution

A new utility for multipurpose analysis, SOLVERSTAT, taking advantage of the versatility of spreadsheets is here described. By means of this tool advanced statistical tests have introduced in Microsoft Excel Solver thus allowing regression diagnostic and discrimination between different models. The utility is here applied to the determination, by UV-Vis spectroscopy, of the stability constant for the uptake of molecular dioxygen by the 1:2 complex of Co(II) with N,N'-dimethylethylenediamine (dmen) in the aprotic solvent dimethylsulfoxide (dmso) at 298 K and in a medium adjusted to 0.1 mol dm(-3) with Et(4)NClO(4). The reliability of the model and parameters obtained are discussed and the results compared with those obtained by Dynafit, a different software package, and by independent voltammetric measurements. The validity of SOLVERSTAT has been also examined applying it to the discrimination between different models already discussed in the literature.

The photodynamic inactivation of Staphylococcus aureus in water using visible light with a new expanded porphyrin

In this work, the results of the application of organic expanded porphyrins in the disinfection of water by the photodynamic inactivation (PDI) technique are presented. The photoinactivation properties of a novel, expanded porphyrin, namely 20-(4-carboxyphenyl)-2,13-dimethyl-3,12-diethyl-(22π) pentaphyrin (PCCox), were tested in the disinfection of water using Staphylococcus aureus as a Gram-positive bacteria model. The data showed that PCCox was effective against S. aureus bacteria at nanomolar concentrations. The variation with irradiation time and concentration was studied using both a multi-LED monochromatic light (λ = 470 nm) and an incandescent light bulb with a wide emission spectrum. A PCCox dosage of 5 μM was sufficient to achieve a 99.997% abatement of S. aureus within 1 h of 40 W/m(2) irradiation with monochromatic light (λ = 470 nm), whereas under the same conditions using irradiation with white light, the abatement was 99.9997%.

Salt-assisted thermal desorption of mercury from contaminated dredging sludge

In this study, we tested a new procedure for the decontamination of mercury-polluted dredging sludge (Marano-Grado Lagoon, northeastern Italy) based on cationic exchange associated with thermal desorption at a low temperature. Four mercury-polluted sludge slurries were treated using thermal desorption at 393 K for 2h. Three different salts, NaCl (sodium chloride), (CH(3))(4)NCl (tetramethylammonium chloride) and (C(4)H(9))(4)NCl (tetrabutylammonium chloride) were used as exchangers. The selected salts have a monovalent cationic part that progressively increases in molecular weight. The results show that the association of cationic exchange with thermal treatment leads to a significant improvement in the removal of mercury from the contaminated material at a low temperature compared to samples that were not treated with salt. The highest levels of decontamination were attained were obtained when the slurries, which had mercury pollution ranging from 20 to 200 ppm, were treated with a 15% solution of (C(4)H(9))(4)NCl. The efficiency of the removal at 393 K (from 24% up to 60%) depended on the nature of the sample. When the samples were treated at a similar temperature without the salt, no remediation of mercury was detected. Our results show that the thermal decontamination temperature can be significantly lowered by this remediation approach, which is the first example based on cationic exchange of the pollutant with an appropriate salt.

Safety of conversion from twice-daily tacrolimus (Prograf) to once-daily prolonged-release tacrolimus (Advagraf) in stable liver transplant recipients

Nonadherence to immunosuppressive regimens among solid organ transplantation to range has been estimated from 15% to 55%. This problem has been identified as a leading cause of preventable graft loss. Tacrolimus once daily Advagraf has been developed to provide a more convenient dosing regimen to improve adherence. The aim of this study was to analyze the safety of a 1:1 dose conversion from twice-daily tacrolimus (Prograf) to Advagraf in 36 stable liver transplant recipients. The tacrolimus whole blood trough level at T0 was 6.7 +/- 2.9 ng/mL with a daily dose of 3.7 +/- 1.8 mg. The mean tacrolimus blood trough levels at T1 (7 days) and T2 (14 days) were 5.8 +/- 2.5 and 5.8 +/- 1.8 ng/mL with mean daily doses of 3.9 +/- 1.9 and 4.1 +/- 1.8 mg, respectively. There was no significant difference between T0, T1, and T2, either for tacrolimus blood trough levels or for tacrolimus daily dosages. Liver and renal function tests remained stable; no episodes of acute rejection were encountered after the conversion. A switching policy using a dose ratio of 1:1 from twice-daily tacrolimus to once-daily prolonged-release tacrolimus was safely applied to stable liver transplant recipients.

Bench-scale tests on ultrasound-assisted acid washing and thermal desorption of mercury from dredging sludge and other solid matrices

A series of ultrasonic assisted acid washing and thermal desorption tests were performed on sludge and other solid matrices with the aim to assay these removal technologies and to determine if the application of low frequency ultrasound was effective to enhance mercury removal. Unpolluted dredging sludge, 820 K calcinated dredging sludge, silica and alumina were characterized, polluted with a known concentration of mercury and treated both by acid washing and thermal desorption with and without low frequency ultrasound application. The acid washing was carried out by a 4% HNO(3) acid solution and the thermal desorption was performed in a 370-620K range. X-ray semi-quantitative analysis of dredging sludge before and after acid washing and granulometric curves of the matrices after the ultrasonic treatment were considered in order to evidence chemical or physical changes during these treatments. Total residual mercury measurements were carried out before and after sonication. Results showed not measurable acid washing extraction from polluted dredging sludge, a little (3%) extraction from 820K heat-treated sludge and a significant (10-20%) extraction from alumina and silica within 120 min of treatment. The ultrasound application gave generally poor improvement of the mercury removal. On the contrary thermal desorption of mercury was somewhat effective for alumina, silica and heat-treated dredging sludge samples in which mercury removal was 30-40% at 370 K and 90-99% at 570 K. Likewise ultrasound application did not improve desorption. Instead, the thermal treatment of dredging sludge had a negligible amount of mercury desorption at 370 K but it reached 95% at 570 K. The application of ultrasound improved the thermal extraction of 25% in the 470-520 K range of temperature.

Comparison of Two Techniques of Arterial Anastomosis During Adult Cadaveric Liver Transplantation

Arterial complications are a major source of morbidity and mortality after orthotopic liver transplantation (OLT). The incidence of hepatic artery thrombosis (HAT) ranges from 1.6% to 8%, with a mortality rate that ranges from 11% to 35%. We have described herein a technique of arterial anastomosis aiming to perform the anastomosis as straight as possible to avoid any kinking, redundancy, or malposition of the artery when the liver is released in its final position. We compared this technique with the traditional technique of arterial anastomosis using an aortic Carrel patch, namely, 198 OLT (group A) with the traditional technique and 117 OLT (group B) with the modified technique. An aorto-hepatic bypass was necessary in 25% of the cases in group A and in 21% of the cases in group B (P = .33). Vascular anomalies were present in 20% of cases in group A and in 27.5% in group B (P = .14). Fourteen cases (7%) of HAT developed in group A versus 0 cases in group B (P = .003). In group B, we experienced 2 (1.7%) late arterial stenoses that were successfully treated using percutaneous transluminal angioplasty. The 14 cases of HAT occurring in group A were successfully managed using immediate surgical revascularization with graft salvage in 6 cases (43%), whereas the remaining 8 cases needed urgent retransplantation. We suggest that a technique of arterial anastomosis aimed at avoiding kinking, redundancy, or malposition of the artery may be a viable option to reduce the risk of HAT after OLT.

Selective Bilirubin Removal by Plasma Treatment With Plasorba BR-350 for Early Cholestatic Graft Dysfunction

Early cholestatic graft dysfunction is a frequent cause of morbidity after orthotopic liver transplantation (OLT). We analyze the role of selective bilirubin plasma absorption (PAP) using Plasorba BR-350 in 4 OLT patients who had experienced early severe cholestatic graft dysfunction within 15 days after transplantation. Patients were treated with 3 consecutive cycles of PAP with Plasorba BR-350. The median amount of plasma treated was 7500 mL. Median treatment duration was 231 minutes. The average plasma bilirubin level was 37 +/- 1 mg/dL before PAP and decreased to 15 +/- 0.2 mg/dL at the end of the third cycle of PAP; 3 of 4 cases had progressive bilirubin normalization after PAP. The average amount of bilirubin removed from the plasma of the patients during each PAP treatment was 143 +/- 24 mg. At the beginning of each cycle of PAP, the Plasorba BR-350 was able to remove >90% of the total plasma bilirubin, a percentage that decreased to 60%, 50%, and 40% after 2 L, 4 L, and 7 L of plasma were treated, respectively. Liver biopsies performed after the third treatment showed reduced cholestasis when compared with the pretreatment biopsy specimen. The preliminary data suggested that PAP selective for bilirubin removal may not only reduce the bilirubin level, but may also improve the histological pattern of the graft in terms of reduced cholestatic signs.

Long-Range-Distance NMR Effects in a Protein Labeled with a Lanthanide–DOTA Chelate

A two-thiol reactive lanthanide-DOTA (1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid) chelate, CLaNP-3 (CLaNP=caged lanthanide NMR probe), was synthesized for the rigid attachment to cysteine groups on a protein surface, and used to obtain long-range-distance information from the {15N,1H} HSQC spectra of the protein-lanthanide complex. The DOTA ring exhibits several isomers that are in exchange; however, single resonances were observed for most amide groups in the protein, allowing determination of a single, apparent magnetic-susceptibility tensor. Pseudocontact shifts caused by Yb-containing CLaNP-3 were observed for atoms at 15-35 A from the metal. By using Gd-containing CLaNP-3, relaxation effects were observed, allowing distances up to 30 A from the paramagnetic center to be determined accurately. Similar results were obtained with a Gd-DTPA (diethylene-triaminepentaacetic acid) chelate, CLaNP-1, bound in the same bidentate manner to the protein. This study demonstrates that bidentate attachment of a paramagnetic probe enables determination of long-range distances.

Synthesis and biological evaluation of new pentaphyrin macrocycles for photodynamic therapy

This paper describes the synthesis and in-depth characterization of two new porphyrogenic macrocycles 1 and 2, and provides an evaluation of these molecules as photosensitizer agents. By tuning the reaction conditions and starting from readily available 1,9-diformyl-5-phenyldipyrromethane (4) and tripyrrane dicarboxylic acid (3), both the nonaromatic isopentaphyrin 1, composed of a 24 pi-electron macrocycle, and the aromatic pentaphyrin 2, composed of a 22 pi-electron macrocycle, were obtained in good yield and purity. Confocal laser microscopy and cytofluorimetry studies showed that the newly synthesized pentaphyrins penetrate the cell membranes and localize mainly in the cytoplasm. In the absence of light, 1 and 2 exhibit a nonsignificant cytotoxic effect at concentrations up to 3 mug/mL. In contrast, the synthesized pentaphyrins, when delivered to cells at 1.5 or 3 microg/mL and irradiated with white light (8 mW/cm(2)), promoted a strong and dose-dependent phototoxic effect in four different cell lines. FACS and caspase-3/7 activation assays demonstrated that the pentaphyrins cause cell death by apoptosis.

Cobalt(II) Dioxygen Carriers Based on Simple Diamino Ligands: Kinetic and ab Initio Studies

The kinetics of the oxygenation reaction of CoL2(2+) complexes (L=ethylenediamine (en), N,N'-dimethylethylenediamnine (dmen)) have been investigated in dimethyl sulfoxide (dmso) at 298 K and in a medium adjusted to 0.1 mol dm(-3) with Et4NClO4 by means of a UV-vis spectrophotometric technique. The reaction mechanisms are consistent with the fast formation of superoxo 1:1 initial CoL2-O2 species (L=en, dmen), whereas the dimeric mu-peroxo (CoL2)2O2 adduct is formed only when L=en, in the rate determining step. The kinetic results are discussed taking into account the effects of ligand/solvent substitution. EPR results give information on the electronic structure and the coordination geometry of the Co(II) complexes and further confirm the stoichiometry of the species formed. Ab initio calculations provide insights on the geometrical parameters of all the complexes investigated and allow us to draw some hypotheses about the influence of H.H nonbonded interactions in the eventual formation of the dimeric mu-peroxo (CoL2)2O2 complexes. Solvational effects are also considered. The formation of the (CoL3)2O2 adduct is also proved when L=en by means of O2 volumetric absorption.

Thermodynamic stability and kinetic inertness of MS-325, a new blood pool agent for magnetic resonance imaging

Stability constants were measured for complexes formed between a modified DTPA ligand and the metal ions Gd(III), Eu(III), Fe(III), Ca(II), Cu(II), and Zn(II) at 25 degrees C in 0.1 M NaClO4. The gadolinium complex of this ligand is MS-325, a novel blood pool contrast agent for magnetic resonance imaging currently undergoing clinical trials. Stability constants were determined by 4 different methods: direct pH titration, pH titration with competition by EDTA, competition with DTPA using an HPLC-MS detection system, and competition with Eu(III) by monitoring equilibrium by luminescence spectroscopy. The 1:1 stability constants, log beta101, are the following: Gd, 22.06 (23.2 in 0.1 M Me4NCl); Eu, 22.21; Fe, 26.66; Ca, 10.45; Cu, 21.3; Zn, 17.82. The exchange kinetics of the Gd complex, MS-325, with the radioactive tracer (152,154)Eu were studied at 25 degrees C in 0.1 M NaClO4. The exchange reaction has acid-dependent and acid-independent terms. The rate expression is given by the following: R = k(a)[GdL][H]2 + kb[GdL][Gd][H] + kc[GdL][Gd]. The rate constants were determined to be the following: k(a) = 1.84 x 10(6) M(-2) x min(-1), kb = 2.87 x 10(3) M(-2) x min(-1), kc = 3.72 x 10(-3) M(-1) x min(-1). MS-325 is 2-3 times more stable than GdDTPA at pH 7.4 and is 10-100 times more kinetically inert.