912 research outputs found
Evidence for orbital ordering in LaCoO3
We present powder and single crystal X-ray diffraction data as evidence for a
monoclinic distortion in the low spin (S=0) and intermediate spin state (S=1)
of LaCoO3. The alternation of short and long bonds in the ab plane indicates
the presence of eg orbital ordering induced by a cooperative Jahn-Teller
distortion. We observe an increase of the Jahn-Teller distortion with
temperature in agreement with a thermally activated behavior of the Co3+ ions
from a low-spin ground state to an intermediate-spin excited state.Comment: Accepted to Phys. Rev.
Bevacizumab in association with de Gramont 5-fluorouracil/folinic acid in patients with oxaliplatin-, irinotecan-, and cetuximab-refractory colorectal cancer: a single-center phase 2 trial.
BACKGROUND: The aim of the current study was the investigation of the value of bevacizumab+5-fluorouracil(5-FU)/folinic acid in patients with advanced colorectal cancers who have exhausted standard chemotherapy options. METHODS: The authors included 48 heavily pretreated patients (colon:rectum, 33:15; men:women, 23:25; median age, 63 years; range, 27-79 years) whose disease had progressed during or within an oxaliplatin-based first-line chemotherapy, an irinotecan-based second-line regimen, and a third-line treatment with cetuximab plus weekly irinotecan. Bevacizumab was given at a dose of 5 mg/kg. 5-FU/folinic acid was administered according to the de Gramont schedule. RESULTS: The response rate was 6.25%, and 30.4% of patients demonstrated stable disease as the best response. The median time to disease progression was 3.5 months (95% confidence interval [95% CI], 2.3-6.9 months), and the median survival time was 7.7 months (95% CI, 3.9-11.9 months). The most common grade 3 to 4 side toxicities (graded according to the National Cancer Institute Common Toxicity Criteria [version 2.0]) were: diarrhea (20.8%), fatigue (14.5%), and stomatitis (12.5%). Grade 3 to 4 hemorrhage occurred in 8 patients (16.6%), including 4 cases of bleeding in the gastrointestinal tract. Other relatively common adverse events such as hypertension, thrombosis, and bowel perforation were reported in 50%, 18.7%, and 4.16%, of patients respectively. CONCLUSIONS: The data from the current study suggest a modest but significant clinical benefit of bevacizumab+de Gramont schedule in heavily pretreated colorectal cancer patients. Copyright (c) 2009 American Cancer Society
Early magnesium reduction in advanced colorectal cancer patients treated with cetuximab plus irinotecan as predictive factor of efficacy and outcome
Introduction: Magnesium plays a role in a large number of cellular metabolic reactions.
Cetuximab is able to induce hypomagnesemia by interfering with magnesium (Mg2+) transport
in the kidney.We designed this trial to investigate if Mg2+ serum level modifications may be related
with clinical response andoutcome in advancedcolorectal cancer patients during treatment with
cetuximab plus irinotecan.
Experimental Design: Sixty-eight heavily pretreatedmetastatic colorectal cancer patients were
evaluatedfor Mg2+ serum levels at the following time points: before; 6 hours; and1, 7, 14, 21, 50,
and92 days after the start of treatment.
Results: Basal Mg2+ median levels were significantly decreased just 7 days after the first
anticancer infusion and progressively decreased from the 7th day onward, reaching the highest
significance at the last time point (P < 0.0001).Twenty-five patients showeda reduction in median
Mg2+ circulating levels of at least 20% within the 3rdweek after the first infusion. Patients with
this reduction showed a response rate of 64.0% versus 25.6% in the nonreduced Mg2+ group.
The median time to progression was 6.0 versus 3.6 months in the reduced Mg2+ group andin that
without reduction, respectively (P < 0.0001). Overall survival was longer in patients with Mg2+
reduction than in those without (10.7 versus 8.9 months).
Conclusions: Our results confirm that cetuximab treatment may induce a reduction of Mg2+
circulating levels andoffer the first evidence that Mg2+ reduction may represent a new predictive
factor of efficacy in advanced colorectal cancer patients treated with cetuximab plus irinoteca
Specific heat and magnetization study on single crystals of a frustrated, quasi one-dimensional oxide: Ca3Co2O6
Specific heat and magnetization measurements have been carried out under a
range of magnetic fields on single crystals of Ca3Co2O6. This compound is
composed of Ising magnetic chains that are arranged on a triangular lattice.
The intrachain and interchain couplings are ferromagnetic and
antiferromagnetic, respectively. This situation gives rise to geometrical
frustration, that bears some similarity to the classical problem of a
two-dimensional Ising triangular antiferromagnet. This paper reports on the
ordering process at low-T and the possibility of one-dimensional features at
high-T.Comment: 7 pages, 6 figures, accepted for publication in PR
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Developing European conservation and mitigation tools for pollination services: approaches of the STEP (Status and Trends of European Pollinators) project
Pollinating insects form a key component of European biodiversity, and provide a vital ecosystem service to crops and wild plants. There is growing evidence of declines in both wild and domesticated pollinators, and parallel declines in plants relying upon them. The STEP project (Status and Trends of European Pollinators, 2010-2015, www.stepproject.net) is documenting critical elements in the nature and extent of these declines, examining key functional traits associated with pollination deficits, and developing a Red List for some European pollinator groups. Together these activities are laying the groundwork for future pollinator monitoring programmes. STEP is also assessing the relative importance of potential drivers of pollinator declines, including climate change, habitat loss and fragmentation, agrochemicals, pathogens, alien species, light pollution, and their interactions. We are measuring the ecological and economic impacts of declining pollinator services and floral resources, including effects on wild plant populations, crop production and human nutrition. STEP is reviewing existing and potential mitigation options, and providing novel tests of their effectiveness across Europe. Our work is building upon existing and newly developed datasets and models, complemented by spatially-replicated campaigns of field research to fill gaps in current knowledge. Findings are being integrated into a policy-relevant framework to create evidence-based decision support tools. STEP is establishing communication links to a wide range of stakeholders across Europe and beyond, including policy makers, beekeepers, farmers, academics and the general public. Taken together, the STEP research programme aims to improve our understanding of the nature, causes, consequences and potential mitigation of declines in pollination services at local, national, continental and global scales
Synchronization of multi-phase oscillators: An Axelrod-inspired model
Inspired by Axelrod's model of culture dissemination, we introduce and
analyze a model for a population of coupled oscillators where different levels
of synchronization can be assimilated to different degrees of cultural
organization. The state of each oscillator is represented by a set of phases,
and the interaction --which occurs between homologous phases-- is weighted by a
decreasing function of the distance between individual states. Both ordered
arrays and random networks are considered. We find that the transition between
synchronization and incoherent behaviour is mediated by a clustering regime
with rich organizational structure, where some of the phases of a given
oscillator can be synchronized to a certain cluster, while its other phases are
synchronized to different clusters.Comment: 6 pages, 5 figure
Исследование теплопереноса при воспламенении типичного лесного горючего материала (ветвь хвойного дерева) при воздействии высокотемпературной среды
Объект исследования – ветвь хвойного дерева. Предмет исследования – моделирование теплопереноса в слоистой структуре ветви хвойного дерева при тепловом воздействии от фронта лесного пожара. Исходные данные – теплофизические характеристики хвойного дерева.The object of study is a branch of a coniferous tree. The subject of the study is the modeling of heat transfer in a layered structure of a branch of a coniferous tree under thermal effects from the front of a forest fire. Baseline data - thermophysical characteristics of coniferous wood
SHREC 2011: robust feature detection and description benchmark
Feature-based approaches have recently become very popular in computer vision
and image analysis applications, and are becoming a promising direction in
shape retrieval. SHREC'11 robust feature detection and description benchmark
simulates the feature detection and description stages of feature-based shape
retrieval algorithms. The benchmark tests the performance of shape feature
detectors and descriptors under a wide variety of transformations. The
benchmark allows evaluating how algorithms cope with certain classes of
transformations and strength of the transformations that can be dealt with. The
present paper is a report of the SHREC'11 robust feature detection and
description benchmark results.Comment: This is a full version of the SHREC'11 report published in 3DO
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