1,127 research outputs found
Roughness and multiscaling of planar crack fronts
We consider numerically the roughness of a planar crack front within the
long-range elastic string model, with a tunable disorder correlation length
. The problem is shown to have two important length scales, and the
Larkin length . Multiscaling of the crack front is observed for scales
below , provided that the disorder is strong enough. The asymptotic
scaling with a roughness exponent is recovered for scales
larger than both and . If , these regimes are separated
by a third regime characterized by the Larkin exponent .
We discuss the experimental implications of our results.Comment: 8 pages, two figure
MRI texture analysis in differentiating luminal A and luminal B breast cancer molecular subtypes - a feasibility study
ConclusionsTexture features which measure randomness, heterogeneity or smoothness and homogeneity may either directly or indirectly reflect underlying growth patterns of breast tumours. TA and volumetric analysis may provide a way to evaluate the biologic aggressiveness of breast tumours and provide aid in decisions regarding therapeutic efficacy.</p
Spatial fluctuations in transient creep deformation
We study the spatial fluctuations of transient creep deformation of materials
as a function of time, both by Digital Image Correlation (DIC) measurements of
paper samples and by numerical simulations of a crystal plasticity or discrete
dislocation dynamics model. This model has a jamming or yielding phase
transition, around which power-law or Andrade creep is found. During primary
creep, the relative strength of the strain rate fluctuations increases with
time in both cases - the spatially averaged creep rate obeys the Andrade law
, while the time dependence of the spatial
fluctuations of the local creep rates is given by . A similar scaling for the fluctuations is found in the logarithmic
creep regime that is typically observed for lower applied stresses. We review
briefly some classical theories of Andrade creep from the point of view of such
spatial fluctuations. We consider these phenomenological, time-dependent creep
laws in terms of a description based on a non-equilibrium phase transition
separating evolving and frozen states of the system when the externally applied
load is varied. Such an interpretation is discussed further by the data
collapse of the local deformations in the spirit of absorbing state/depinning
phase transitions, as well as deformation-deformation correlations and the
width of the cumulative strain distributions. The results are also compared
with the order parameter fluctuations observed close to the depinning
transition of the 2 Linear Interface Model or the quenched Edwards-Wilkinson
equation.Comment: 27 pages, 18 figure
Centralized repeated resectability assessment of patients with colorectalliver metastases during first-line treatment : prospective study
Y Background: Metastasectomy is probably underused in metastatic colorectal cancer. The aim of this study was to investigate the effect of centralized repeated assessment on resectability rate of liver metastases. Methods: The prospective RAXO study was a nationwide study in Finland. Patients with treatable metastatic colorectal cancer at any site were eligible. This planned substudy included patients with baseline liver metastases between 2012 and 2018. Resectability was reassessed by the multidisciplinary team at Helsinki tertiary referral centre upfront and twice during first-line systemic therapy. Outcomes were resectability rates, management changes, and survival. Results: Of 812 patients included, 301 (37.1 per cent) had liver-only metastases. Of these, tumours were categorized as upfront resectable in 161 (53.5 per cent), and became amenable to surgery during systemic treatment in 63 (20.9 per cent). Some 207 patients (68.7 per cent) eventually underwent liver resection or ablation. At baseline, a discrepancy in resectability between central and local judgement was noted for 102 patients (33.9 per cent). Median disease-free survival (DFS) after first resection was 20 months and overall survival (OS) 79 months. Median OS after diagnosis of metastatic colorectal cancer was 80, 32, and 21 months in R0-1 resection, R2/ablation, and non-resected groups, and 5-year OS rates were 68, 37, and 9 per cent, respectively. Liver and extrahepatic metastases were present in 511 patients. Of these, tumours in 72 patients (14.1 per cent) were categorized as upfront resectable, and 53 patients (10.4 per cent) became eligible for surgery. Eventually 110 patients (21.5 per cent) underwent liver resection or ablation. At baseline, a discrepancy between local and central resectability was noted for 116 patients (22.7 per cent). Median DFS from first resection was 7 months and median OS 55 months. Median OS after diagnosis of metastatic colorectal cancer was 79, 42, and 17 months in R0-1 resection, R2/ablation, and non-resected groups, with 5-year OS rates of 65, 39, and 2 per cent, respectively. Conclusion: Repeated centralized resectability assessment in patients with colorectal liver metastases improved resection and survival rates.Peer reviewe
Statistical Physics of Fracture Surfaces Morphology
Experiments on fracture surface morphologies offer increasing amounts of data
that can be analyzed using methods of statistical physics. One finds scaling
exponents associated with correlation and structure functions, indicating a
rich phenomenology of anomalous scaling. We argue that traditional models of
fracture fail to reproduce this rich phenomenology and new ideas and concepts
are called for. We present some recent models that introduce the effects of
deviations from homogeneous linear elasticity theory on the morphology of
fracture surfaces, succeeding to reproduce the multiscaling phenomenology at
least in 1+1 dimensions. For surfaces in 2+1 dimensions we introduce novel
methods of analysis based on projecting the data on the irreducible
representations of the SO(2) symmetry group. It appears that this approach
organizes effectively the rich scaling properties. We end up with the
proposition of new experiments in which the rotational symmetry is not broken,
such that the scaling properties should be particularly simple.Comment: A review paper submitted to J. Stat. Phy
Mechanism of action of probiotics
The modern diet doesn't provide the required amount of beneficial bacteria. Maintenance of a proper microbial ecology in the host is the main criteria to be met for a healthy growth. Probiotics are one such alternative that are supplemented to the host where by and large species of Lactobacillus, Bifidobacterium and Saccharomyces are considered as main probiotics. The field of probiotics has made stupendous strides though there is no major break through in the identification of their mechanism of action. They exert their activity primarily by strengthening the intestinal barrier and immunomodulation. The main objective of the study was to provide a deep insight into the effect of probiotics against the diseases, their applications and proposed mechanism of action
Treatment response of colorectal cancer liver metastases to neoadjuvant or conversion therapy : a prospective multicentre follow-up study using MRI, diffusion-weighted imaging and H-1-MR spectroscopy compared with histology (subgroup in the RAXO trial)
Background: Colorectal cancer liver metastases respond to chemotherapy and targeted agents not only by shrinking, but also by morphologic and metabolic changes. The aim of this study was to evaluate the value of advanced magnetic resonance imaging (MRI) methods in predicting treatment response and survival. Patients and methods: We investigated contrast-enhanced MRI, apparent diffusion coefficient (ADC) in diffusionweighted imaging and H-1-magnetic resonance spectroscopy (1H-MRS) in detecting early morphologic and metabolic changes in borderline or resectable liver metastases, as a response to first-line neoadjuvant or conversion therapy in a prospective substudy of the RAXO trial (NCT01531621, EudraCT2011-003158-24). MRI findings were compared with histology of resected liver metastases and KaplaneMeier estimates of overall survival (OS). Results: In 2012-2018, 52 patients at four Finnish university hospitals were recruited. Forty-seven patients received neoadjuvant or conversion chemotherapy and 40 liver resections were carried out. Low ADC values (below median) of the representative liver metastases, at baseline and after systemic therapy, were associated with partial response according to RECIST criteria, but not with morphologic MRI changes or histology. Decreasing ADC values following systemic therapy were associated with improved OS compared to unchanged or increasing ADC, both in the liver resected subgroup (5-year OS rate 100% and 34%, respectively, P = 0.022) and systemic therapy subgroup (5-year OS rate 62% and 23%, P = 0.049). H-1-MRS revealed steatohepatosis induced by systemic therapy. Conclusions: Low ADC values at baseline or during systemic therapy were associated with treatment response by RECIST but not with histology, morphologic or detectable metabolic changes. A decreasing ADC during systemic therapy is associated with improved OS both in all patients receiving systemic therapy and in the resected subgroup.Peer reviewe
Treatment response of colorectal cancer liver metastases to neoadjuvant or conversion therapy : a prospective multicentre follow-up study using MRI, diffusion-weighted imaging and H-1-MR spectroscopy compared with histology (subgroup in the RAXO trial)
Background: Colorectal cancer liver metastases respond to chemotherapy and targeted agents not only by shrinking, but also by morphologic and metabolic changes. The aim of this study was to evaluate the value of advanced magnetic resonance imaging (MRI) methods in predicting treatment response and survival. Patients and methods: We investigated contrast-enhanced MRI, apparent diffusion coefficient (ADC) in diffusionweighted imaging and H-1-magnetic resonance spectroscopy (1H-MRS) in detecting early morphologic and metabolic changes in borderline or resectable liver metastases, as a response to first-line neoadjuvant or conversion therapy in a prospective substudy of the RAXO trial (NCT01531621, EudraCT2011-003158-24). MRI findings were compared with histology of resected liver metastases and KaplaneMeier estimates of overall survival (OS). Results: In 2012-2018, 52 patients at four Finnish university hospitals were recruited. Forty-seven patients received neoadjuvant or conversion chemotherapy and 40 liver resections were carried out. Low ADC values (below median) of the representative liver metastases, at baseline and after systemic therapy, were associated with partial response according to RECIST criteria, but not with morphologic MRI changes or histology. Decreasing ADC values following systemic therapy were associated with improved OS compared to unchanged or increasing ADC, both in the liver resected subgroup (5-year OS rate 100% and 34%, respectively, P = 0.022) and systemic therapy subgroup (5-year OS rate 62% and 23%, P = 0.049). H-1-MRS revealed steatohepatosis induced by systemic therapy. Conclusions: Low ADC values at baseline or during systemic therapy were associated with treatment response by RECIST but not with histology, morphologic or detectable metabolic changes. A decreasing ADC during systemic therapy is associated with improved OS both in all patients receiving systemic therapy and in the resected subgroup.Peer reviewe
Transverse-field Ising spin chain with inhomogeneous disorder
We consider the critical and off-critical properties at the boundary of the
random transverse-field Ising spin chain when the distribution of the couplings
and/or transverse fields, at a distance from the surface, deviates from its
uniform bulk value by terms of order with an amplitude . Exact
results are obtained using a correspondence between the surface magnetization
of the model and the surviving probability of a random walk with time-dependent
absorbing boundary conditions. For slow enough decay, , the
inhomogeneity is relevant: Either the surface stays ordered at the bulk
critical point or the average surface magnetization displays an essential
singularity, depending on the sign of . In the marginal situation,
, the average surface magnetization decays as a power law with a
continuously varying, -dependent, critical exponent which is obtained
analytically. The behavior of the critical and off-critical autocorrelation
functions as well as the scaling form of the probability distributions for the
surface magnetization and the first gaps are determined through a
phenomenological scaling theory. In the Griffiths phase, the properties of the
Griffiths-McCoy singularities are not affected by the inhomogeneity. The
various results are checked using numerical methods based on a mapping to free
fermions.Comment: 11 pages (Revtex), 11 figure
EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA); Scientific Opinion on establishing Food-Based Dietary Guidelines
This Opinion of the EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA) provides guidance on the translation of nutrient based dietary advice into guidance, intended for the European population as a whole, on the contribution of different foods or food groups to an overall diet that would help to maintain good health through optimal nutrition (food-based dietary guidelines). The main focus of this Opinion is put on the scientific process of developing food-based dietary guidelines (FBDG) for the diverse European populations, following a stepwise approach which should ideally consist of: 1) Identification of diet-health relationships, 2) Identification of country specific diet-related health problems, 3) Identification of nutrients of public health importance, 4) Identification of foods relevant for FBDG, 5) Identification of food consumption patterns, 6) Testing and optimising FBDG and 7) Graphical representations of FBDG. FBDG should focus on the diet-disease relationships of particular relevance to the specific population and should be developed using a multi-disciplinary approach. The early involvement of stakeholders is recommended to promote the acceptance of the outcome. FBDG should be consistent with other public policies that have an impact on food availability and be integrated with other policies related to health promotion. Once established, FBDG should be implemented and their impact monitored and evaluate
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