Kinetics and mechanism of gas-phase thermolysis using headspace-gas chromatographic analysis

Headspace gas chromatography is employed in order to study the thermal decomposition reaction of gaseous di-tert-butyl peroxide (DTBP) in the 130°C to 160°C temperature range and in the presence of n-hexane as the internal standard and nitrogen as the carrier gas. The reaction exclusively yields acetone and ethane as products. First-order kinetics are observed, including when the surface-to-volume ratio (S/V) of the Pyrex 20-mL vial employed as the reactor is increased by packing it with silanized glass wool. However, a small increase in the rate constant values is observed at each temperature, which supports a heterogeneous surface process in DTBP decomposition. The rate constant's dependence on the homogeneous unimolecular decomposition reaction corresponds to the O-O bond rupture of the DTBP molecule in a stepwise three-stage mechanism. Thus, the relevant question of the participation of a surface catalytic effect in the DTBP gas-phase thermolysis can easily be assessed through the procedure described in this work. In general, this is advantageous for the rapid investigation of the reaction kinetics of volatile compounds at different temperatures.Laboratorio de Estudio de Compuestos Orgánico

Kinetics and mechanism of gas-phase thermolysis using headspace-gas chromatographic analysis

Headspace gas chromatography is employed in order to study the thermal decomposition reaction of gaseous di-tert-butyl peroxide (DTBP) in the 130°C to 160°C temperature range and in the presence of n-hexane as the internal standard and nitrogen as the carrier gas. The reaction exclusively yields acetone and ethane as products. First-order kinetics are observed, including when the surface-to-volume ratio (S/V) of the Pyrex 20-mL vial employed as the reactor is increased by packing it with silanized glass wool. However, a small increase in the rate constant values is observed at each temperature, which supports a heterogeneous surface process in DTBP decomposition. The rate constant's dependence on the homogeneous unimolecular decomposition reaction corresponds to the O-O bond rupture of the DTBP molecule in a stepwise three-stage mechanism. Thus, the relevant question of the participation of a surface catalytic effect in the DTBP gas-phase thermolysis can easily be assessed through the procedure described in this work. In general, this is advantageous for the rapid investigation of the reaction kinetics of volatile compounds at different temperatures.Laboratorio de Estudio de Compuestos Orgánico

Cortinas de álamo

Un recurso forestal con futuro en la PatagoniaEn la actualidad, existen aproximadamente 11.324 km de cortinas forestales de álamos en la región Patagónica. En el Alto Valle de Río Negro y Neuquén, donde se concentra la mayoría de los álamos en Patagonia, constituyen un importante recurso forestal. Los usos de su madera son muy variados y se encuentran en continua evolución, desarraigándose la idea de que son maderas de baja calidad. Actualmente se proyecta en la región un importante desarrollo en la industria maderera, lo que posiciona a estos árboles como un recurso forestal potencial. Docentes y estudiantes de la Universidad Nacional del Comahue estudian su madera con el fin de generar información necesaria para abrir aún más el abanico de sus posibilidades de uso. Los resultados obtenidos la ubican en posición competitiva con otras maderas utilizadas con fines estructurales

Carboplatin plus paclitaxel in extensive small cell lung cancer: a multicentre phase 2 study

A multicentre phase 2 trial (single-stage design) was undertaken to test the efficacy and toxicity of carboplatin (AUC 6 according to Calvert) plus paclitaxel (175 mg/m23-h infusion) every 4 weeks in the first line treatment of patients affected by extensive small cell lung cancer. The primary end-point of the trial was the objective response rate. 31 objective responses among 50 patients were considered necessary to proceed to a phase 3 trial. 48 patients were enrolled (median age 59 years). Treatment was very well tolerated. 3 patients (6.2%) had a complete response and 23 (47.9%) a partial response, for an overall response rate of 54.2% (95% CI: 39.2–68.6) Median time to progression was 5.7 months (95% CI: 5.2–6.2). Median survival was 9.6 months (95% CI: 7.2–14.6), with a median follow-up time of alive patients of 12 months. At 1 year, the probability of being progression-free or alive was 0.16 and 0.43, respectively. In conclusion, carboplatin plus paclitaxel as given in the present study is very well tolerated but not sufficiently active to warrant phase 3 comparison with standard chemotherapy regimens. © 2001 Cancer Research Campaign http://www.bjcancer.co

Propiedades mecánicas de la madera de álamos de cortinas forestales de Río Negro, Patagonia, Argentina

En la provincia de Río Negro, Argentina, existen en la actualidad 6000 km de longitud lineal de cortinas cortavientos de álamo. Su función principal es la protección de cultivos frutihortícolas, pero son además un recurso forestal real y potencial. El objetivo de este trabajo es conocer algunas propiedades mecánicas de la madera estos álamos, información no existente y esencial para optimizar su aprovechamiento y maximizar su valor en diferentes usos. Se apearon 15 ejemplares de los álamos más representados en cortinas forestales (álamo chileno, conti 12 y boleana) de chacras de la localidad de Allen. De cada árbol se extrajo una troza de 1,5 m de largo desde la cual se obtuvieron probetas para ensayos de propiedades mecánicas de resistencia estática de flexión, compresión (Norma ASTM D-143), resistencia al aplastamiento (Norma ASTM D-5764-97) y dureza (Norma IRAM-9570). Por un lado, los resultados obtenidos fueron del orden de los reportados para madera de otros álamos cultivados en diferentes zonas de nuestro país, algunas de ellas habilitadas para uso estructural. Por otro lado, los valores obtenidos fueron del rango de los reportados para pino ponderosa, madera ampliamente utilizada en Patagonia en la construcción de cabreadas, estructuras portantes (tirantes, vigas, columnas, etc.) y bastidores de entramados en paneles estructurales. La madera de boleana y conti 12 presentó mayores valores de resistencia a la flexión, a la compresión y al desgaste que la del álamo chileno (MOR flexión: 66,7 Mpa, MOE flexión: 8562,15 Mpa, MOR compresión: 31,22 Mpa, MOE compresión: 8270,52 Mpa, dureza radial: 1,63 kN/cm2). La resistencia al aplastamiento no presentó variaciones significativas entre ellos (conti 12: 29,42 Mpa, boleana: 30,08 Mpa y chileno: 29,65 Mpa). Estos resultados resaltan el potencial que presenta la madera de los álamos de cortinas forestales de los valles irrigados de Río Negro para ampliar sus posibilidades de uso.In Río Negro province, Argentina, there are currently 6000 km of linear length of poplar windbreaks. Its main function is the protection of fruit and vegetable crops but they are also a real and potential forest resource. The objective of this work is to know the mechanical properties of the wood these poplars, nonexistent and essential information to optimize their use and maximize their value in different uses. Fifteen specimens of the most represented poplars in forest curtains (chileno, conti 12 and boleana) of farms in Allen were cutted. From each tree a 1.5 m long log was extracted to obtain wood for mechanical properties tests of static resistance of bending, compression (ASTM D-143), dowel bearing strenght (ASTM D-5764-97) and hardness (IRAM-9570). The results obtained were of the order of those reported for wood from other poplars grown in different areas of our country, some of them accepted for structural use. On the other hand, the values obtained were from the range of those reported for ponderosa pine, wood widely used in Patagonia in the construction, load-bearing structures (beams, columns, etc.) and frames of trusses in structural panels. The wood of boleana and conti 12 presented higher values of resistance to flexion, compression and hardness than chilean poplar (MOR flexion: 66.7 Mpa, MOE flexion: 8562.15 Mpa, MOR compression: 31.22 Mpa, MOE compression: 8270.52 MPa, radial hardness: 1.63 kN / cm2). The dowel bearing strenght did not show significant variations among them (conti 12: 29.42 MPa, boleana: 30.08 MPa and chilean: 29.65 MPa). These conclusions highlight the potential of poplar wood from Río Negro forest windbreaks to expand their possibilities of use.Fil: Medina, A.A. Universidad Nacional del Comahue, Asentamiento Universitario San Martín de los Andes; ArgentinaFil: Manzione, Pablo. Universidad Nacional del Comahue. Facultad de Ingeniería. Departamento de Mecánica Aplicada. Grupo de Estudio de Polímeros Sintéticos y Naturales; ArgentinaFil: Baucis, Agustín. Universidad Nacional del Comahue, Asentamiento Universitario San Martín de los Andes; ArgentinaFil: Catalán, Mariano. Universidad Nacional del Comahue, Asentamiento Universitario San Martín de los Andes; ArgentinaFil: Laffitte, Lorena. Universidad Nacional del Comahue, Asentamiento Universitario San Martín de los Andes; ArgentinaFil: Andía, Ismael R. Universidad Nacional del Comahue, Asentamiento Universitario San Martín de los Andes; Argentin

Weekly paclitaxel as first-line chemotherapy in elderly advanced breast cancer patients: a phase II study of the Gruppo Italiano di Oncologia Geriatrica (GIOGer)

Background: First-line chemotherapy regimens suitable for elderly advanced breast cancer patients are still not defined. Patients and methods: Women with stage III or IV breast cancer aged >_70 years were enrolled in a phase II study aimed to evaluate both activity and toxicity of weekly paclitaxel. Among 46 planned patients, at least 18 responses and not more than seven unacceptable toxic events are required for a favourable conclusion. Paclitaxel 80 mg/m2 was administered weekly for 3 weeks every 28 days. Results: Unacceptable toxicity occurred in seven out of 46 patients evaluated for toxicity [15.2%; exact 95% confidence interval (CI) 7.6% to 28.2%] and was represented by one case of febrile neutropenia, one case of severe allergic reaction and five cases of cardiac toxicity. Among 41 patients evaluated for response, a complete response occurred in two (4.9%) patients and a partial response in 20 (48.8%), with an overall response rate of 53.7% (exact 95% CI 38.7% to 67.9%). The median progression-free survival was 9.7 months (95% CI 8.5\u201318.7) and median survival was 35.8 months (95% CI 19\u2013not defined). Conclusions: Weekly paclitaxel is highly active in elderly advanced breast cancer patients. Data on cardiovascular complications, however, indicate the need for a careful monitoring of cardiac function before and during chemotherap

Tutorial do pacote Agriwater para modelagem espacial da evapotranspiração no software R.

Este trabalho apresenta: 1) o pacote Agriwater em ambiente R, implementado para automatizar a utilização de imagens Sentinel-2, Landsat-8 e sensor Modis com o algoritmo Safer, e 2) a primeira aplicação do Safer a imagens Sentinel-2, em uma área do Semiárido nordestino, a imagens Modis, na região do afloramento do Aquífero Guarani no estado de São Paulo, e a imagens Landsat-8 na região central do estado de São Paulo. Também é apresentado um procedimento de conversão de imagens do satélite Sentinel-2 no software QGIS, para adequar os arquivos ao formato pedido pelo pacote Agriwater, que pode ser aplicado aos outros sensores. O enfoque do presente trabalho é a apresentação de um passo a passo compreensível sobre o uso do pacote Agriwater. Uma discussão aprofundada dos resultados obtidos pela modelagem da primeira aplicação está disponível em Silva et al. (2019a), da segunda aplicação, em Silva et al. (2018) e da terceira aplicação, em Silva et al. (2019b).bitstream/item/207129/1/5165.pd

\u201cA randomised factorial trial of sequential doxorubicin and CMF vs CMF and chemotherapy alone vs chemotherapy followed by goserelin plus tamoxifen as adjuvant treatment of node-positive breast cancer\u201d

The sequential doxorubicin \u2192 CMF (CMF = cyclophosphamide, methotrexate, fluorouracil) regimen has never been compared to CMF in a randomised trial. The role of adding goserelin and tamoxifen after chemotherapy is unclear. In all, 466 premenopausal node-positive patients were randomised to: (a) CMF 7 6 cycles (CMF); (b) doxorubicin 7 4 cycles followed by CMF 7 6 cycles (A \u2192 CMF); (c) CMF 7 6 cycles followed by goserelin plus tamoxifen 7 2 years (CMF \u2192 GT); and (d) doxorubicin 7 4 cycles followed by CMF 7 6 cycles followed by goserelin plus tamoxifen 7 2 years (A \u2192 CMF \u2192 GT). The study used a 2 7 2 factorial experimental design to assess: (1) the effect of the chemotherapy regimens (CMF vs A 7 CMF or arms a + c vs b + d) and (2) the effect of adding GT after chemotherapy (arms a + b vs c + d). At a median follow-up of 72 months, A \u2192 CMF as compared to CMF significantly improved disease-free survival (DFS) with a multivariate hazard ratio (HR) = 0.740 (95% confidence interval (CI): 0.556-0.986; P = 0.040) and produced a nonsignificant improvement of overall survival (OS) (HR = 0.764; 95% CI: 0.489-1.193). The addition of GT after chemotherapy significantly improved DFS (HR = 0.74; 95% CI: 0.555-0.987; P = 0.040), with a nonsignificant improvement of OS (HR = 0.84; 95% CI: 0.54-1.32). A \u2192 CMF is superior to CMF. Adding GT after chemotherapy is beneficial for premenopausal node-positive patients. \ua9 2005 Cancer Research UK

Prevalence and management of pain in Italian patients with advanced non-small-cell lung cancer

Pain is a highly distressing symptom for patients with advanced cancer. WHO analgesic ladder is widely accepted as a guideline for its treatment. Our aim was to describe pain prevalence among patients diagnosed with advanced non-small-cell lung cancer (NSCLC), impact of pain on quality of life (QoL) and adequacy of pain management. Data of 1021 Italian patients enrolled in three randomised trials of chemotherapy for NSCLC were pooled. QoL was assessed by EORTC QLQ-C30 and LC-13. Analgesic consumption during the 3 weeks following QoL assessment was recorded. Adequacy of pain management was evaluated by the Pain Management Index (PMI). Some pain was reported by 74% of patients (42% mild, 24% moderate and 7% severe); 50% stated pain was affecting daily activities (30% a little, 16% quite a bit, 3% very much). Bone metastases strongly affected presence of pain. Mean global QoL linearly decreased from 64.9 to 36.4 from patients without pain to those with severe pain (P<0.001). According to PMI, 616 out of 752 patients reporting pain (82%) received inadequate analgesic treatment. Bone metastases were associated with improved adequacy and worst pain with reduced adequacy at multivariate analysis. In conclusion, pain is common in patients with advanced NSCLC, significantly affects QoL, and is frequently undertreated. We recommend that: (i). pain self-assessment should be part of oncological clinical practice; (ii). pain control should be a primary goal in clinical practice and in clinical trials; (iii). physicians should receive more training in pain management; (iv). analgesic treatment deserves greater attention in protocols of anticancer treatment