The kinetic modeling of soot precursors in ethylene flames

A comprehensive, semidetailed kinetic scheme describing hydrocarbon oxidation is applied to the simulation of premixed, rich, sooting, ethylene laminar flames. The main goal of this work is to investigate the soot precursor and aromatic pathways under different operative conditions in terms of temperatures and feed composition. The modeling computations are in good agreement with the experimental data and are also comparable with predictions of different kinetic schemes present in the literature. The recombination reactions of resonantly stabilized radicals (such as propargyl) and C2H2 addition on linear dehydrogenated molecules (C4Hx) are taken into account to explain formation of the first aromatic ring. Two major channels of benzene and polycyclic aromatic hydrocarbon (PAH) formation are observed in the conditions under analysis. The former, which is not included in previous literature schemes, is faster and occurs first (where the conversion is still low). It is governed by ethylene and vinyl radical, which, through butadiene and butenyl radicals, explain the formation of cyclopentadiene and through further successive additions give rise to benzene and styrene. This mechanism should be the starting point for the initial formation of heavy highly hydrogenated compounds. Acetylene and resonantly stabilized radicals are mainly responsible for the successive aromatic growth. The study of such pathways is also important for the analysis of low NOx burners and new process alternatives, such as recirculating flue gases, where pollutant emission reductions are pursued by the use of low-temperature flames. The comparisons with experimental data for pure ethylene pyrolysis at lower temperatures (1100 K) confirms the validity of the assumed mechanism

Partial oxidation of hydrocarbons: an experimental and kinetic modeling study

Partial oxidation offers an attractive alternative route to form olefins from alkanes in simple and low cost reactors. Using Pt catalyst on alpha-alumina support in a reactor with a contact time of a few milliseconds, olefin selectivities of up to 70% have been achieved at large alkane and O-2 conversion without catalyst fouling and deactivation. Under suitable conditions, cyclohexane oxidative dehydrogenation to form cyclohexene prevails over the decomposition reactions toward butadiene and smaller olefins. A general and extensive pyrolysis and oxidation reaction scheme, involving about 150 species and 3000 reactions, has been used to verify the importance of homogeneous reaction paths in explaining the experimental results of oxidative pyrolysis of alkanes from propane up to hexanes. For higher alkanes, relevant cracking occurs even at short contact times and considerable ethylene and propylene yields are obtained. Comparisons between model predictions and experiments at different temperatures (1000-1300 K), residence times (1-5 ms), and alkane to oxygen ratios (0.5-1.2) suggest that surface reaction steps play a significant role in this process especially for the smaller alkanes and at the lower temperatures (higher alkane to oxygen ratios). In these conditions, catalyst activity promotes the reactivity of the system and improves CO2 formation as well as oxidative dehydrogenation. Few simplified catalytic steps coupled with the homogeneous reaction scheme allow us to explain the experimental data. This model is a useful tool for investigating and optimizing operating conditions and reactor configurations

A Phase II study of Bendamustine in Combination With Rituximab as Initial Treatment for Patients With Indolent non-follicular non-Hodgkin's Lymphoma

The purpose of this phase 2 study was to determine the activity and safety of 6 cycles of bendamustine and 8 rituximab (RB) as first-line treatment of adult patients with advanced stage non-follicular indolent non-Hodgkin lymphomas (INFL). The primary endpoint was the complete response rate (CRR) with expected CRR of 75%. Sixty-nine patients were enrolled; median age was 65 years (45-75), 65% were male, 93% of patients had stage IV disease. Complete and overall response rates were 48% (95% IC 35.6-60.2), and 86% (IC 75.0-92.8). The most common grade 3/4 adverse events were neutropenia (43%), thrombocytopenia (7%), anemia (4%); whereas the rate of febrile neutropenia was very low (3%). At a median follow up of 22 months (1-43 months), 2-year progression free survival was 89% (IC: 79-95), and 2-year overall survival was 96% (IC: 87-99). RB combination is active and well tolerated in patients with advanced stage previously untreated INFL

Epidemiology and treatment approaches in management of invasive fungal infections in hematological malignancies: Results from a single-centre study.

Invasive fungal infections (IFIs) are a leading cause of morbidity and attributable mortality in oncohematologic patients. Timely diagnosis is essential but challenging. Herein we retrospectively describe 221 cases of antifungal treatments (AFT) administered in a monocentric real-life cohort of hematological malignancies. Between January 2010 and July 2017, 196 oncohematologic patients were treated with AFT at our Hematology Department. Diagnosis of IFIs was carried out according to EORTC/MSG-2008 guidelines.The most represented disease was acute myeloid leukemia (104 patients). Median age was 61 years; at fever onset 177 (80%) patients had a neutrophil count<0.5x109/L. Twenty-nine (13%) patients were receiving antifungal prophylaxis (26 posaconazole, 2 fluconazole, 1 itraconazole). The incidence of AFT was 13%. Serum galactomannan antigen (GM) was positive in 20% of the tested cases, while 85% of the patients had a CT scan suggestive for IFI. Twenty-one percent of these cases had a GM positive. Sixty-five out of 196 patients (33%) showed positive culture results, in particular Candida spp. were identified in 45 isolates, while Aspergillus spp. in 16 cases. Fourteen patients presented multiple positivity. Twenty-two (10%) cases were classified as proven IFIs, 61 (28%) as probable and 81 (37%) as possible, but 57 (26%) cases could not be classified. Fifty-nine percent of the patients received single agent AFT, 37% sequential AFT, 8% a combination regimen. Liposomal-amphotericin-B was the most used AFT. IFIs attributable mortality was 20%. This epidemiologic survey underlined a persistent significant use of AFT and a high mortality rate of IFIs. We suggest that further powerful diagnostic approaches should be investigated to improve the diagnostic accuracy and potential therapeutic implication

Fludarabine, cyclophosphamide, and rituximab in patients with advanced, untreated, indolent B-cell nonfollicular lymphomas: Phase 2 study of the Italian Lymphoma Foundation

BACKGROUND: Indolent nonfollicular non-Hodgkin B-cell lymphomas (INFLs) are clonal mature B-cell proliferations for which treatment has not been defined to date. METHODS: In this phase 2 study of patients with advanced INFL, the authors evaluated the efficacy and safety of first-line rituximab, fludarabine, and cyclophosphamide (FCR) as induction immunochemotherapy (rituximab 375 mg/m 2 intravenously on day 1 of each cycle and on days 1 and 14 of cycles 4 and 5; fludarabine 25 mg/m 2 intravenously on days 2-4, cyclophosphamide 250 mg/m 2 intravenously on Days 2-4) every 28 days for 6 cycles followed by a maintenance phase with 4 infusions of rituximab (375 mg/m 2 intravenously on day 1) every 2 months for responders. RESULTS: Forty-seven patients were enrolled. Among 46 evaluable patients (28 men; median age, 59 years), 19 were diagnosed with lymphoplasmacytic lymphoma, 21 were diagnosed with small lymphocytic lymphoma, and 6 were diagnosed with nodal marginal zone lymphoma. The overall response rate after maintenance was 89.1% with a 67.4% complete remission (CR) rate (CR/unconfirmed CR) and a 21.7% partial response rate. After a median follow-up of 40.9 months, the failure-free survival and progression-free survival rates both were 90.1%, and the overall survival rate was 97.4%. The main toxicity was hematologic, and related grade 3 and 4 neutropenia was observed in 55.3% of patients. CONCLUSIONS: FCR induction therapy followed by a short maintenance phase is a highly effective regimen with acceptable toxicity. Cancer 2012. © 2011 American Cancer Society. Indolent nonfollicular non-Hodgkin B-cell lymphomas are clonal mature B-cell proliferations for which treatment has not been defined to date. The combination of rituximab, fludarabine, and cyclophosphamide as induction immunochemotherapy followed by a short maintenance phase with rituximab is a highly effective regimen with acceptable toxicity in this subset of lymphomas. Copyright © 2011 American Cancer Society