630 research outputs found

    Tallimustine in advanced previously untreated colorectal cancer, a phase II study.

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    Tallimustine is a novel benzoyl mustard derivative from distamycin A with a unique mode of action. It is a DNA minor groove binder and produces highly sequence-specific alkylations. Previous studies have shown significant anti-tumour effects in animal models. We performed a phase II study in previously untreated patients with advanced colorectal cancer, using a schedule of i.v. bolus infusions of 900 microgram m-2 once every 4 weeks. Seventeen patients were enrolled, and no responses were documented in 14 evaluable patients. Toxicity mainly consisted a highly selective neutropenia, which warrants further investigation of this agent in combination with myeloid growth factors

    Microbial soil quality indicators under different crop rotations and tillage management.

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    An experiment was carried out under field conditions to assess the effects of soil management (no-tillage- NT and conventional tillage- CT) and crop rotation systems on microbial biomass-C (Cmic), basal soil respiration (BSR), metabolic quotient (qCO2), soil organic carbon content (Corg) and microbial carbon to organic carbon ratio (Cmic/Corg). Soil samples were collected on an area cultivated with wheat as winter crop and soybean as summer crop, both in rotation with vetch, maize and oats. Samples were also collected in a secondary forest used as reference. Data of each management system (NT and CT) were compared to forest area by ?t? test (p<0.05) and crop rotations were compared by Tukey test (p<0.05). All data were submitted to multivariate analysis (Principal Component Analysis - PCA). There were observed significant differences (?t? test; p<0.05) for Cmic, BSR, qCO2 and Cmic/Corg between NT and CT, by which NT values resemble those for forest area. For crop rotations significant differences (Tukey test; p<0.05) were found only for BSR and qCO2. The sum of the two first principal components on the PCA explained about 75% of the data variation. PCA showed NT closest to forest area than CT, especially treatments with soybean and vetch as consecutive crops. The forest area-NT clustering was mostly due to Cmic and Cmic/Corg relationship. Results indicate that the NT system is more sustainable than the CT system and can contribute for the accumulation a greater quantity of carbon in soil

    A Study of the Formation of Single- and Double-Walled Carbon Nanotubes by a CVD Method

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    The reduction in H2/CH4 atmosphere of aluminum-iron oxides produces metal particles small enough to catalyze the formation of single-walled carbon nanotubes. Several experiments have been made using the same temperature profile and changing only the maximum temperature (800-1070 °C). Characterizations of the catalyst materials are performed using notably 57Fe Mo¨ssbauer spectroscopy. Electron microscopy and a macroscopical method are used to characterize the nanotubes. The nature of the iron species (Fe3+, R-Fe, ç-Fe-C, Fe3C) is correlated to their location in the material. The nature of the particles responsible for the high-temperature formation of the nanotubes is probably an Fe-C alloy which is, however, found as Fe3C by postreaction analysis. Increasing the reduction temperature increases the reduction yield and thus favors the formation of surface-metal particles, thus producing more nanotubes. The obtained carbon nanotubes are mostly single-walled and double-walled with an average diameter close to 2.5 nm. Several formation mechanisms are thought to be active. In particular, it is shown that the second wall can grow inside the first one but that subsequent ones are formed outside. It is also possible that under given experimental conditions, the smallest (<2 nm) catalyst particles preferentially produce double-walled rather than single-walled carbon nanotubes

    Clinical Relevance of Dissolution Testing in Quality by Design

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    Quality by design (QbD) has recently been introduced in pharmaceutical product development in a regulatory context and the process of implementing such concepts in the drug approval process is presently on-going. This has the potential to allow for a more flexible regulatory approach based on understanding and optimisation of how design of a product and its manufacturing process may affect product quality. Thus, adding restrictions to manufacturing beyond what can be motivated by clinical quality brings no benefits but only additional costs. This leads to a challenge for biopharmaceutical scientists to link clinical product performance to critical manufacturing attributes. In vitro dissolution testing is clearly a key tool for this purpose and the present bioequivalence guidelines and biopharmaceutical classification system (BCS) provides a platform for regulatory applications of in vitro dissolution as a marker for consistency in clinical outcomes. However, the application of these concepts might need to be further developed in the context of QbD to take advantage of the higher level of understanding that is implied and displayed in regulatory documentation utilising QbD concepts. Aspects that should be considered include identification of rate limiting steps in the absorption process that can be linked to pharmacokinetic variables and used for prediction of bioavailability variables, in vivo relevance of in vitro dissolution test conditions and performance/interpretation of specific bioavailability studies on critical formulation/process variables. This article will give some examples and suggestions how clinical relevance of dissolution testing can be achieved in the context of QbD derived from a specific case study for a BCS II compound

    ARTIFICIAL INTELLIGENCE FOR REAL-TIME MONITORING OF LOGS ON THE MADEIRA RIVER: A CASE STUDY ON JIRAU HYDROELECTRIC PLANT

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    The Jirau and Santo Antônio hydroelectric plants in Rondônia implemented a methodology using high-range cameras and artificial intelligence technology to address the challenge of managing logs transported by the river during floods. By applying machine learning techniques and neural networks, the system automatically monitors log transport and accumulation. Python 3, along with libraries like OpenCV, PIL, Numpy, and Pytorch, was utilized for efficient implementation. The methodology includes frame selection, log and debris segmentation, perspective correction, and log counting. Training was conducted using annotated images, and the detection process involved color segmentation, noise removal, and morphological operations. The calculated log and debris occupancy results were stored in a SQL database and presented on Power BI dashboards. The system aims to improve log management, ensuring power generation and ecological order are safeguarded

    Espectroscopia infravermelha para a determinação de carbono do solo: perspectiva de um método economicamente viável e ambientalmente seguro.

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    O objetivo deste trabalho foi apresentar a utilidade das técnicas DRIFTS e NIRS na determinação quantitativa de carbono total (CT) determinado por combustão via seca e carbono orgânico (CORG) determinado por oxidação com dicromato de potássio, usando uma série heterogênea e representativa de solos do Brasil. Calibrações foram feitas para o número total das amostras e para as sub-populações de amostras com base no teor de C, classe de solo e grupo textural.bitstream/CNPAF/25440/1/comt_126.pd

    Estudo de variáveis de solo, vegetação e condicionamento de amostras de solo sobre a biomassa microbiana do solo no Estado do Rio de Janeiro.

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    Umidade da amostra. Pré-condicionamento da amostra. A influência da profundidade e tipo de cobertura. Tipos de solos.bitstream/CNPAB-2010/27315/1/doc090.pd

    A large geometric distortion in the first photointermediate of rhodopsin, determined by double-quantum solid-state NMR

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    Double-quantum magic-angle-spinning NMR experiments were performed on 11,12-C-13(2)-retinylidene-rhodopsin under illumination at low temperature, in order to characterize torsional angle changes at the C11-C12 photoisomerization site. The sample was illuminated in the NMR rotor at low temperature (similar to 120 K) in order to trap the primary photointermediate, bathorhodopsin. The NMR data are consistent with a strong torsional twist of the HCCH moiety at the isomerization site. Although the HCCH torsional twist was determined to be at least 40A degrees, it was not possible to quantify it more closely. The presence of a strong twist is in agreement with previous Raman observations. The energetic implications of this geometric distortion are discussed

    Photoproduction of phi(1020) mesons on the proton at large momentum transfer

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    The cross section for ϕ\phi meson photoproduction on the proton has been measured for the first time up to a four-momentum transfer -t = 4 GeV^2, using the CLAS detector at the Thomas Jefferson National Accelerator Facility. At low four-momentum transfer, the differential cross section is well described by Pomeron exchange. At large four-momentum transfer, above -t = 1.8 GeV^2, the data support a model where the Pomeron is resolved into its simplest component, two gluons, which may couple to any quark in the proton and in the ϕ\phi.Comment: 5 pages; 7 figure
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