Mixed plastics waste valorization through tandem chemical oxidation and biological funneling

Mixed plastics waste represents an abundant and largely untapped feedstock for the production of valuable products. The chemical diversity and complexity of these materials, however, present major barriers to realizing this opportunity. In this work, we show that metal-catalyzed autoxidation depolymerizes comingled polymers into a mixture of oxygenated small molecules that are advantaged substrates for biological conversion. We engineer a robust soil bacterium, Pseudomonas putida, to funnel these oxygenated compounds into a single exemplary chemical product, either β-ketoadipate or polyhydroxyalkanoates. This hybrid process establishes a strategy for the selective conversion of mixed plastics waste into useful chemical products.

177Lu-DOTATATE molecular radiotherapy for childhood neuroblastoma

This study tested the principle that (68)Ga-DOTATATE PET/CT may be used to select children with primary refractory or relapsed high-risk neuroblastoma for treatment with (177)Lu-DOTATATE and evaluated whether this is a viable therapeutic option for those children.

METHODS

Between 2008 and 2010, 8 children with relapsed or refractory high-risk neuroblastoma were studied with (68)Ga-DOTATATE PET/CT. The criterion of eligibility for (177)Lu-DOTATATE therapy was uptake on the diagnostic scan equal to or higher than that of the liver.

RESULTS

Of the 8 children imaged, 6 had abnormally high uptake on the (68)Ga-DOTATATE PET/CT scan and proceeded to treatment. Patients received 2 or 3 administrations of (177)Lu-DOTATATE at a median interval of 9 wk and a median administered activity of 7.3 GBq. Of the 6 children treated, 5 had stable disease by the response evaluation criteria in solid tumors (RECIST). Of these 5 children, 2 had an initial metabolic response and reduction in the size of their lesions, and 1 patient had a persistent partial metabolic response and reduction in size of the lesions on CT, although the disease was stable by RECIST. One had progressive disease. Three children had grade 3 and 1 child had grade 4 thrombocytopenia. No significant renal toxicity has been seen.

CONCLUSION

(68)Ga-DOTATATE can be used to image children with neuroblastoma and identify those suitable for molecular radiotherapy with (177)Lu-DOTATATE. We have shown, for what is to our knowledge the first time, that treatment with (177)Lu-DOTATATE is safe and feasible in children with relapsed or primary refractory high-risk neuroblastoma. We plan to evaluate this approach formally in a phase I-II clinical trial.

Polyoxometalate-based gelating networks for entrapment and catalytic decontamination

A polyoxometalate-based polymer with multifunctional capabilities including rapid gelation and catalytic decontamination of toxic or odorous compounds is realized.

Electrochemical Lignin Conversion

Lignin is the largest source of renewable aromatic compounds, making the recovery of aromatic compounds from this material a significant scientific goal. Recently, many studies have reported on lignin depolymerization and upgrading strategies. Electrochemical approaches are considered to be low cost, reagent free, and environmentally friendly, and can be carried out under mild reaction conditions. In this Review, different electrochemical lignin conversion strategies, including electrooxidation, electroreduction, hybrid electro-oxidation and reduction, and combinations of electrochemical and other processes (e. g., biological, solar) for lignin depolymerization and upgrading are discussed in detail. In addition to lignin conversion, electrochemical lignin fractionation from biomass and black liquor is also briefly discussed. Finally, the outlook and challenges for electrochemical lignin conversion are presented.

Transcatheter gelfoam embolization of posttraumatic bleeding pseudoaneurysms

Diagnostic angiography combined with transcatheter therapeutic embolization is a simple and effective means of treating complex clinical situations associated with posttraumatic hemorrhage. Bleeding pseudoaneurysms, even when large, can be readily managed by this combined modality with resultant decrease in morbidity and hospital stay. Five patients with posttraumatic pseudoaneurysms are presented. All five were treated by transcatheter therapeutic embolization with Gelfoam. Of these five cases, three involved extremities, one involved the retroperitoneal space, and the last was of renal origin. Two of the five cases still required surgical intervention after initial successful therapeutic embolization, one for recurrent bleeding from collaterals and the other for evacuation of a massive pseudoaneurysm which was causing distraction of fracture fragments. The early use of angiography in suspected cases of posttraumatic hemorrhage, together with careful evaluation of potential collateral supply, is stressed. The use of transcatheter therapeutic embolization in the extremities as presented here is yet another example of the ever-broadening applicability of this technique.

Results of a quality assurance review of external beam radiation therapy in the International Society of Paediatric Oncology (Europe) Neuroblastoma Group's High-risk Neuroblastoma Trial: a SIOPEN study

PURPOSE

Radiation therapy is important for local control in neuroblastoma. This study reviewed the compliance of plans with the radiation therapy guidelines of the International Society of Paediatric Oncology (Europe) Neuroblastoma Group (SIOPEN) High-Risk Trial protocol.

METHODS AND MATERIALS

The SIOPEN trial central electronic database has sections to record diagnostic imaging and radiation therapy planning data. Individual centers may upload data remotely, but not all centers involved in the trial chose to use this system. A quality scoring system was devised based on how well the radiation therapy plan matched the protocol guidelines, to what extent deviations were justified, and whether adverse effects may result. Central review of radiation therapy planning was undertaken retrospectively in 100 patients for whom complete diagnostic and treatment sets were available. Data were reviewed and compared against protocol guidelines by an international team of radiation oncologists and radiologists. For each patient in the sample, the central review team assigned a quality assurance score.

RESULTS

It was found that in 48% of patients there was full compliance with protocol requirements. In 29%, there were deviations for justifiable reasons with no likely long-term adverse effects resulting. In 5%, deviations had occurred for justifiable reasons, but that might result in adverse effects. In 1%, there was a deviation with no discernible justification, which would not lead to long-term adverse events. In 17%, unjustified deviations were noted, with a risk of an adverse outcome resulting.

CONCLUSIONS

Owing to concern over the proportion of patients in whom unjustified deviations were observed, a protocol amendment has been issued. This offers the opportunity for central review of radiation therapy plans before the start of treatment and the treating clinician a chance to modify plans.

Radiation exposure to comforters and carers during paediatric molecular radiotherapy

BACKGROUND

To show whether the incidental radiation exposure received by comforters and carers of children undergoing molecular radiotherapy was kept as low as reasonably achievable and was within English national dose constraints.

PROCEDURE

The radiation exposure of adult comforters and carers was routinely monitored with a whole body personal dose meter while the child was in hospital. Data were collected on iodine-131 meta-iodobenzylguanidine (¹³¹ I-mIBG), lutetium-177 DOTATATE (¹⁷⁷ Lu-DOTATATE), and iodine-131 sodium iodide (¹³¹ I-NaI) treatments.

RESULTS

Data were available for 50 treatments with high-administered activity double-infusion ¹³¹ I-mIBG and 12 single administrations; 15 ¹⁷⁷ Lu-DOTATATE treatments and 28 ¹³¹ I-NaI administrations. The median age was 7 years (1-18). The median administered activity of: ¹³¹ I-mIBG was 16.2 GBq (6.8-59 GBq) for double infusion patients and 8.1 GBq (5.26-16.25 GBq) for single administrations; ¹⁷⁷ Lu-DOTATATE was 7.2 GBq (2.5-7.5 GBq); and ¹³¹ I-NaI was 3 GBq for thyroid remnant ablation and 5.5 GBq for cancer therapy. The median number of comforters and carers for all administrations was 2 (range 1-9). The median exposure values for comforters and carers for high-administered activity ¹³¹ I-mIBG administrations was 302 µSv (0-5282 µSv); for single fraction ¹³¹ I-mIBG 163 µSv (3-3104 µSv); ¹⁷⁷ Lu-DOTATATE 6 µSv (1-79 µSv); and ¹³¹ I-NaI 37 µSv (0-274 µSv). Only one of the comforters and carers exceeded the dose constraint of 5 mSv.

CONCLUSIONS

Doses to comforters and carers were in all but one case within the dose constraint nationally recommended by the Health Protection Agency, now part of Public Health England. New evidence is presented which show that comforter and carer radiation exposure levels from paediatric molecular radiotherapy in routine clinical practice are acceptably low. Pediatr Blood Cancer 2015;62:235-239. © 2014 Wiley Periodicals, Inc.

Multi-Tasking POM Systems

Polyoxometalate (POM)-based materials of current interest are summarized, and specific types of POM-containing systems are described in which material facilitates multiple complex interactions or catalytic processes. We specifically highlight POM-containing multi-hydrogen-bonding polymers that form gels upon exposure to select organic liquids and simultaneously catalyze hydrolytic or oxidative decontamination, as well as water oxidation catalysts (WOCs) that can be interfaced with light-absorbing photoelectrode materials for photoelectrocatalytic water splitting.

A Layered Manganese(IV)-Containing Heteropolyvanadate with a 1:14 Stoichiometry

A novel manganese(IV)-containing symmetrical heteropolyvanadate was prepared by the transformation of K7[MnV13O38]·18H2O (K7MnV13) to K4Li2[MnV14O40]·21H2O (1) at pH 4. The heteropolyanion [MnV14O40](6-) (MnV14) is composed of a MnO6 octahedron surrounded by 14 edge-sharing VO6 octahedra. The simplified representation of MnV14 has a new topology termed jba1 with a total point symbol of {3(10)}2{3(14).4(7)}4{3(18).4(10)}8{3(44).4(46).5}. In the crystal lattice of 1, MnV14 packs with potassium ions, forming a 2D layered K2[MnV14O40](4-) network (ABABAB...). Four K(+) ions cap the four square O4 faces of MnV14, apparently stabilizing the heteropolyanion. Compound 1 catalyzes the t-BuOOH-based oxidation of 2-chloroethyl ethyl sulfide (a mustard gas simulant). The magnetic and catalytic properties of 1 are discussed.

A solvent-free solid catalyst for the selective and color-indicating ambient-air removal of sulfur mustard

Bis(2-chloroethyl) sulfide or sulfur mustard (HD) is one of the highest-tonnage chemical warfare agents and one that is highly persistent in the environment. For decontamination, selective oxidation of HD to the substantially less toxic sulfoxide is crucial. We report here a solvent-free, solid, robust catalyst comprising hydrophobic salts of tribromide and nitrate, copper(II) nitrate hydrate, and a solid acid (Nafion^TM) for selective sulfoxidation using only ambient air at room temperature. This system rapidly removes HD as a neat liquid or a vapor. The mechanisms of these aerobic decontamination reactions are complex, and studies confirm reversible formation of a key intermediate, the bromosulfonium ion, and the role of Cu(II). The latter increases the rate four-fold by increasing the equilibrium concentration of bromosulfonium during turnover. Cu(II) also provides a colorimetric detection capability. Without HD, the solid is green, and with HD, it is brown. Bromine K-edge XANES and EXAFS studies confirm regeneration of tribromide under catalytic conditions. Diffuse reflectance infrared Fourier transform spectroscopy shows absorption of HD vapor and selective conversion to the desired sulfoxide, HDO, at the gas-solid interface.

Autoxidation Catalysis for Carbon-Carbon Bond Cleavage in Lignin

Selective lignin depolymerization is a key step in lignin valorization to value-added products, and there are multiple catalytic methods to cleave labile aryl-ether bonds in lignin. However, the overall aromatic monomer yield is inherently limited by refractory carbon-carbon linkages, which are abundant in lignin and remain intact during most selective lignin deconstruction processes. In this work, we demonstrate that a Co/Mn/Br-based catalytic autoxidation method promotes carbon-carbon bond cleavage in acetylated lignin oligomers produced from reductive catalytic fractionation. The oxidation products include acetyl vanillic acid and acetyl vanillin, which are ideal substrates for bioconversion. Using an engineered strain of Pseudomonas putida, we demonstrate the conversion of these aromatic monomers to cis,cis-muconic acid. Overall, this study demonstrates that autoxidation enables higher yields of bioavailable aromatic monomers, exceeding the limits set by ether-bond cleavage alone.

Catalytic carbon-carbon bond cleavage in lignin via manganese-zirconium-mediated autoxidation

Efforts to produce aromatic monomers through catalytic lignin depolymerization have historically focused on aryl-ether bond cleavage. A large fraction of aromatic monomers in lignin, however, are linked by various carbon-carbon (C-C) bonds that are more challenging to cleave and limit the yields of aromatic monomers from lignin depolymerization. Here, we report a catalytic autoxidation method to cleave C-C bonds in lignin-derived dimers and oligomers from pine and poplar. The method uses manganese and zirconium salts as catalysts in acetic acid and produces aromatic carboxylic acids as primary products. The mixtures of the oxygenated monomers are efficiently converted to cis,cis-muconic acid in an engineered strain of Pseudomonas putida KT2440 that conducts aromatic O-demethylation reactions at the 4-position. This work demonstrates that autoxidation of lignin with Mn and Zr offers a catalytic strategy to increase the yield of valuable aromatic monomers from lignin.

The radiology corner. Bouveret's syndrome

A case of gallstone obturation of the duodenal bulb is presented. The general topic of gallstone ileus is briefly discussed and a review of the reported cases of Bouveret's syndrome is presented. The radiographic criteria for diagnosis of these entities are emphasized.