Biochar increases nitrogen retention and lowers greenhouse gas emissions when added to composting poultry litter.

Biochar has intrinsic and nascent structural and sorption properties that may alter the physical and chemical properties of a composting mixture thus influencing the production of greenhouse gases [GHGs; nitrous oxide (N2O) and methane (CH4)]. In this study, contrasting biochars produced from greenwaste (GWB) or poultry litter (PLB) were incorporated into a composting mixture containing poultry litter and straw, and GHG emissions were measured in situ during composting using Fourier Transform Infrared Spectroscopy (FTIR). Emissions of N2O from the biochar-amended composting mixtures decreased significantly (P<0.05) soon after commencement of the composting process compared with the non-amended control. The cumulative emissions of N2O over 8weeks in the GWB composting mixture (GWBC), PLB composting mixture (PLBC) and control (no biochar) were 4.2, 5.0 and 14.0gN2O-Nkg-1 of total nitrogen (TN) in composting mixture, respectively (P<0.05). The CH4 emissions were significantly (P<0.05) lower in the GWBC and PLBC treatments than the control during the period from day 8 to day 36, when anaerobic conditions likely prevailed. The cumulative CH4 emissions were 12, 18 and 80mg CH4-Ckg-1 of total carbon (TC) for the GWBC, PLBC and control treatments, respectively, though due to wide variation between replicates this difference was not statistically significant. The cumulative N2O and CH4 emissions were similar between the GWBC and PLBC despite differences in properties of the two biochars. X-ray Photoelectron Spectroscopy (XPS) analysis and SEM imaging of the composted biochars indicated the presence of iron oxide compounds and amine-NH3 on the surface and pores of the biochars (PLB>GWB). The change in nitrogen (N) functional groups on the biochar surface after composting is evidence for sorption and/or reaction with N from labile organic N, mineral N, and gaseous N (e.g. N2O). The concentration of NH4+ increased during the thermophilic phase and then decreased during the maturation phase, while NO3- accumulated during the maturation phase. Total N retained was significantly (P<0.05) higher in the PLBC (740g) and the GWBC (660g) relative to the control (530g). The TC retained was significantly higher in the GWBC (10.0kg) and the PLBC (8.5kg) cf. the control (6.0kg). Total GHG emissions across the composting period were 50, 63 and 183kg CO2-eqt-1 of initial mass of GWBC, PLBC and control (dry weight basis) respectively. These results support the co-composting of biochar to lower net emissions of GHGs while increasing N retention (and fertiliser N value) in the mature compost.

Video-assisted thoracic surgery systematic mediastinal nodal dissection and stage migration: impact on clinical pathway.

OBJECTIVES: The aim of this study is to investigate the role of routine systematic mediastinal nodal dissection (SND) performed during video-assisted thoracic surgery (VATS) major pulmonary resections (VMPRs) as a staging strategy for non-small-cell lung cancer (NSCLC), compared with preoperative staging by conventional positron emission tomography (PET) and computed tomography (CT) imaging. METHODS: All patients suspected of having early lung cancer (T1-2, N0-1 and M0) were staged preoperatively by CT/PET. During VMPR, all lymph nodes on the right side at stations 2-4, 7, 8, 9, 10 and 11 and on the left stations 4-6, 7, 8, 9, 10, 11 and 3 when indicated were dissected en bloc. Histology was provided on the paraffin-embedded nodes, and patients staged accordingly. Preoperative and postoperative stagings were compared. Stage migration and impact on clinical pathway were noted. Stage IIa and higher were referred for adjuvant chemotherapy. RESULTS: Between April 2007 and January 2011, 106 consecutive patients with suspected primary NSCLC proceeded to VMPR+SND. Histology confirmed NSCLC in 96 patients. Forty-five were men and 51 women. Median age was 68.6 (range 42.8-84.7) years. As many as 91 (94.8%) patients underwent lobectomy, three (3.1%) bilobectomy and two (2.1%) pneumonectomy. PET accurately correlated with SND histological diagnosis in 42 (43.8%) patients. The unexpected N2 disease in cN0-1 was 9/86 (10.5%). SND resulted in 25 stage migrations, upstaged 16 (16.6%) and down-staged nine (9.4%) patients. All upstagings were adenocarcinoma. Four (4.2%) PET-negative patients had multi-station N2 disease. SND resulted in changing the clinical pathway for 19 (20%) patients. Fourteen (14.6%) patients upstaged to qualify for chemotherapy, and 5/9 (5.2%) down-staged patients were saved the chemotherapy. There was no morbidity or mortality attributable to this added procedure. CONCLUSIONS: SND during VMPR is safe and should be routinely performed even when nodal metastases is considered unlikely. VATS-SND is more accurate than PET in staging the mediastinum for NSCLC. PET sensitivity is significantly reduced in adenocarcinoma and might result in stage migration. Adjuvant multidisciplinary treatment should be based on SND staging.