923 research outputs found
Thermal Conductivity, Thermopower, and Figure of Merit of La_{1-x}Sr_xCoO_3
We present a study of the thermal conductivity k and the thermopower S of
single crystals of La_{1-x}Sr_xCoO_3 with 0<= x <= 0.3. For all Sr
concentrations La_{1-x}Sr_xCoO_3 has rather low k values, whereas S strongly
changes as a function of x. We discuss the influence of the temperature- and
the doping-induced spin-state transitions of the Co ions on both, S and k. From
S, k, and the electrical resistivity rho we derive the thermoelectric figure of
merit Z=S^2/(k*rho). For intermediate Sr concentrations we find notably large
values of Z indicating that Co-based materials could be promising candidates
for thermoelectric cooling.Comment: 7 pages, 5 figures included, submitted to Phys. Rev.
Advances in pre-treatment evaluation of pancreatic ductal adenocarcinoma: a narrative review
Background and Objective: Despite advances in the multidisciplinary management of pancreatic cancer, overall prognosis remains poor, due to early progression of the disease. There is a need to also take action in staging, to make it increasingly accurate and complete, to define the setting of the therapeutic strategy. This review was planned to update the current status of pre-treatment evaluation for pancreatic cancer. Methods: We conducted an extensive review, including relevant articles dealing with traditional imaging, functional imaging and minimally invasive surgical procedures before treatment for pancreatic cancer. We searched articles written in English only. Data in the PubMed database, published in the period between January 2000 and January 2022, were retrieved. Prospective observational studies, retrospective analyses and meta-analyses were reviewed and analysed. Key Content and Findings: Each imaging modality (endoscopic ultrasonography, endoscopic retrograde staging laparoscopy) has its own diagnostic advantages and limitations. The sensitivity, specificity and accuracy for each image set are reported. Data that support the increasing role of neoadjuvant therapy (radiotherapy and chemotherapy) and the meaning of a patient-tailored treatment selection, based on tumour staging, are also discussed. Conclusions: A multimodal pre-treatment workup should be searched as it improves staging accuracy, orienting patients with resectable tumors towards surgery, optimizing patient selection with locally advanced tumors to neoadjuvant or definite therapy and avoiding surgical resection or curative radiotherapy in those with metastatic disease
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
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
Gut microbiota-derived propionate reduces cancer cell proliferation in the liver
Peer reviewedPublisher PD
Molecular and phenotypic profiling from base to the crown in maritime pine wood-forming tissue
Researchâą Environmental, developmental and genetic factors affect variation in wood properties
at the chemical, anatomical and physical levels. Here, the phenotypic variation observed
along the tree stem was explored and the hypothesis tested that this variation could be
the result of the differential expression of genes/proteins during wood formation.
âą Differentiating xylem samples of maritime pine (Pinus pinaster) were collected
from the top (crown wood, CW) to the bottom (base wood, BW) of adult trees.
These samples were characterized by Fourier transform infrared spectroscopy (FTIR)
and analytical pyrolysis. Two main groups of samples, corresponding to CW and BW,
could be distinguished from cell wall chemical composition.
âą A genomic approach, combining large-scale production of expressed sequence
tags (ESTs), gene expression profiling and quantitative proteomics analysis, allowed
identification of 262 unigenes (out of 3512) and 231 proteins (out of 1372 spots)
that were differentially expressed along the stem.
âą A good relationship was found between functional categories from transcriptomic
and proteomic data. A good fit between the molecular mechanisms involved in
CWâBW formation and these two types of wood phenotypic differences was also
observed. This work provides a list of candidate genes for wood properties that will
be tested in forward genetic
Critical Dynamics of Magnets
We review our current understanding of the critical dynamics of magnets above
and below the transition temperature with focus on the effects due to the
dipole--dipole interaction present in all real magnets. Significant progress in
our understanding of real ferromagnets in the vicinity of the critical point
has been made in the last decade through improved experimental techniques and
theoretical advances in taking into account realistic spin-spin interactions.
We start our review with a discussion of the theoretical results for the
critical dynamics based on recent renormalization group, mode coupling and spin
wave theories. A detailed comparison is made of the theory with experimental
results obtained by different measuring techniques, such as neutron scattering,
hyperfine interaction, muon--spin--resonance, electron--spin--resonance, and
magnetic relaxation, in various materials. Furthermore we discuss the effects
of dipolar interaction on the critical dynamics of three--dimensional isotropic
antiferromagnets and uniaxial ferromagnets. Special attention is also paid to a
discussion of the consequences of dipolar anisotropies on the existence of
magnetic order and the spin--wave spectrum in two--dimensional ferromagnets and
antiferromagnets. We close our review with a formulation of critical dynamics
in terms of nonlinear Langevin equations.Comment: Review article (154 pages, figures included
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