ABSTRACT
Fuel treatments and other forest restoration thinning practices aim to reduce wildfire risk while building forest resilience to drought, insects, and diseases and increasing aboveground carbon (C) sequestration. However, fuel treatments generate large amounts of unmerchantable woody biomass residues that are often burned in open piles, releasing significant quantities of greenhouse gases and particulates, and potentially damaging the soil beneath the pile. Air curtain burners offer a solution to mitigate these issues, helping to reduce smoke and particulates from burning operations, more fully burn biomass residues compared to pile burning, and eliminate the direct and intense fire contact that can harm soil beneath the slash pile. In an air curtain burner, burning takes place in a controlled environment. Smoke is contained and recirculated by the air curtain, and therefore burning can be conducted under a variety of climatic conditions (e.g., wind, rain, snow), lengthening the burning season for disposal of slash material. The mobile pyrolysis unit that continuously creates biochar was specifically designed to dispose of residual woody biomass at log landings, green wood at landfills, or salvaged logged materials and create biochar in the process. This high-carbon biochar output can be used to enhance soil resilience by improving its chemical, physical, and biological properties and has potential applications in remediating contaminated soils, including those at abandoned mine sites. Here, we describe the general use of this equipment, appropriate siting, loading methods, quenching requirements, and lessons learned about operating this new technology.
Subject(s)
Charcoal , Wood , Wood/chemistry , Charcoal/chemistry , Pyrolysis , Forestry/methodsABSTRACT
A highly enantio- and diastereoselective dynamic kinetic resolution (DKR) of configurationally labile 3-aryl indole-2-carbaldehydes is described. The DKR proceeds via a Rh-catalyzed intermolecular asymmetric reductive aldol reaction with acrylate esters, with simultaneous generation of three stereogenic elements. The strategy relies on the labilization of the stereogenic axis that takes place thanks to a transient Lewis acid-base interaction (LABI) between the formyl group and a thioether moiety strategically located at the ortho' position. The atropisomeric indole products present a high degree of functionalization and can be further converted to a series of axially chiral derivatives, thereby expanding their potential application in drug discovery and asymmetric catalysis.
ABSTRACT
This tutorial review provides a systematic overview of the available methodologies for the atroposelective transformation of (heterobiaryl)biaryl precursors toward the synthesis of enantiomerically enriched products and the conceptual aspects associated to each type of transformation. Depending on the presence or absence of symmetry in the starting material and the participation of racemization or dynamization events along the process, several strategies have been developed, including desymmetrization, classical kinetic resolution (KR), dynamic kinetic resolution (DKR) and dynamic kinetic asymmetric transformation (DYKAT). Seminal contributions and a handful of selected examples are discussed to illustrate the potential of these synthetic tools.
ABSTRACT
BACKGROUND: The results of CHOP-21 (cyclophosphamide, doxorubicin, vincristine and prednisone given every 21 days) for the treatment of aggressive B-cell lymphoma have recently been improved by the addition of rituximab and by increasing the dose density. R-CHOP-14 combines these two approaches. PATIENTS AND METHODS: We present our experience with R-CHOP-14 in a retrospective single-centre review of 50 patients consecutively treated for aggressive B-cell lymphoma. RESULTS: The median age was 59 years and 48% of patients were >60 years. Stage III-IV was present in 62% of the patients and international prognostic index was high-to-intermediate risk or high risk in 32% of the patients. Toxicity was mainly haematological, with grade 3-4 neutropenia observed in 32% and febrile neutropenia in 18%. Other relevant toxicities were peripheral neuropathy in 45% (grade 3 in 4%) and cardiac dysfunction grade 3 in 7.5%. After therapy, 82% of the patients achieved complete response or unproved complete response. With a median follow-up of 30 months, 3-year event-free survival and overall survival were 67% and 82% respectively. CONCLUSIONS: In our experience the combination of RCHOP- 14 is highly effective in patients with aggressive B-cell lymphoma. However special attention must be paid to the control of early and late toxicities.
