Two 3D Fractal-Based Approaches for Topographical Characterization: Richardson Patchwork versus Sdr.

Various methods exist for multiscale characterization of surface topographies, each offering unique insights and applications. The study focuses on fractal-based approaches, distinguishing themselves by leveraging fractals to analyze surface complexity. Specifically, the Richardson Patchwork method, used in the ASME B46.

Geolocalization of water-waves origin within water distribution networks using time reversal of first event detection.

Drinking water distribution networks in urban areas are daily subject to fast propagating pressure waves resulting from routine operations. These water-hammer waves lead to structural aging and facility damages, the origin of which is not easy to find but are sometimes of high managerial interest. In this contribution, we demonstrate that using a reasonable number of high-frequency pressure detectors distributed within the network combined with a proper post-processing method permits a close geolocalization of the damaging wave origin.

CHICKN: extraction of peptide chromatographic elution profiles from large scale mass spectrometry data by means of Wasserstein compressive hierarchical cluster analysis.

Background: The clustering of data produced by liquid chromatography coupled to mass spectrometry analyses (LC-MS data) has recently gained interest to extract meaningful chemical or biological patterns. However, recent instrumental pipelines deliver data which size, dimensionality and expected number of clusters are too large to be processed by classical machine learning algorithms, so that most of the state-of-the-art relies on single pass linkage-based algorithms.

Results: We propose a clustering algorithm that solves the powerful but computationally demanding kernel k-means objective function in a scalable way.

Digital Cultural Heritage Preservation in Art Painting: A Surface Roughness Approach to the Brush Strokes.

There is a growing interest in cultural heritage preservation. The notion of HyperHeritage highlights the creation of new means of communication for the perception and data processing in cultural heritage. This article presents the Digital Surface HyperHeritage approach, an academic project to identify the topography of art painting surfaces at the scale at which the elementary information of sensorial rendering is contained.

Numerical Simulation of Solid Combustion in Microporous Particles.

In the present study, direct numerical simulations for smoldering in simplified geometries are performed for multicomponent and dilatable flows. The reactant gas is passing inside an array of permeable and microporous cylinders. The chemical reaction takes place within the grains.

A reduced-order modeling for efficient design study of artificial valve in enlarged ventricular outflow tracts.

A computational approach is proposed for efficient design study of a reducer stent to be percutaneously implanted in enlarged right ventricular outflow tracts (RVOT). The need for such a device is driven by the absence of bovine or artificial valves which could be implanted in these RVOT to replace the absent or incompetent native valve, as is often the case over time after Tetralogy of Fallot repair. Hemodynamics are simulated in the stented RVOT via a reduce order model based on proper orthogonal decomposition, while the artificial valve is modeled as a thin resistive surface.

Blood Flow Simulations for the Design of Stented Valve Reducer in Enlarged Ventricular Outflow Tracts.

Tetralogy of Fallot is a congenital heart disease characterized over time, after the initial repair, by the absence of a functioning pulmonary valve, which causes regurgitation, and by progressive enlargement of the right ventricle outflow tract (RVOT). Due to this pathological anatomy, available transcatheter valves are usually too small to be deployed there. To avoid surgical valve replacement, an alternative consists in implanting a reducer prior to or in combination with the valve.

Group-wise construction of reduced models for understanding and characterization of pulmonary blood flows from medical images.

3D computational fluid dynamics (CFD) in patient-specific geometries provides complementary insights to clinical imaging, to better understand how heart disease, and the side effects of treating heart disease, affect and are affected by hemodynamics. This information can be useful in treatment planning for designing artificial devices that are subject to stress and pressure from blood flow. Yet, these simulations remain relatively costly within a clinical context.

On the normalization of cerebral blood flow.

Cerebral blood flow (CBF) is the most common parameter for the quantification of brain's function. Literature data indicate a widespread dispersion of values that might be related to some differences in the measurement conditions that are not properly taken into account in CBF evaluation. Using recent high-resolution imaging of the complete cortical microvasculature of primate brain, we perform extensive numerical evaluation of the cerebral perfusion.

Coupling and robustness of intra-cortical vascular territories.

Vascular domains have been described as being coupled to neuronal functional units enabling dynamic blood supply to the cerebral cyto-architecture. Recent experiments have shown that penetrating arterioles of the grey matter are the building blocks for such units. Nevertheless, vascular territories are still poorly known, as the collection and analysis of large three-dimensional micro-vascular networks are difficult.

Evaluation of mouthrinse and dentifrice regimens in an in situ erosion remineralisation model.

Objectives: To compare the effectiveness of dentifrice/mouthrinse regimens in a clinical in situ erosion remineralisation model.

Methods: Thirty-six subjects completed a randomised single-blind cross-over trial of five treatment regimens. R1: Dentifrice A [1450 ppm fluoride as the sodium salt (NaF), 50000 ppm potassium nitrate (KNO(3))] plus 450 ppm fluoride (NaF) rinse; R2: Dentifrice A plus sterile water rinse; R3: Dentifrice B (fluoride-free Dentifrice A) plus sterile water rinse; R4: Dentifrice B plus 450 ppm fluoride (NaF) rinse; R5: Dentifrice C (1000 ppm fluorine as sodium monofluorophosphate, 450 ppm fluoride as NaF) plus sterile water rinse.

Cerebral blood flow modeling in primate cortex.

We report new results on blood flow modeling over large volumes of cortical gray matter of primate brain. We propose a network method for computing the blood flow, which handles realistic boundary conditions, complex vessel shapes, and complex nonlinear blood rheology. From a detailed comparison of the available models for the blood flow rheology and the phase separation effect, we are able to derive important new results on the impact of network structure on blood pressure, hematocrit, and flow distributions.

The effect of brushing time and dentifrice quantity on fluoride delivery in vivo and enamel surface microhardness in situ.

While the clinical anticaries efficacy of fluoride toothpaste is now without question, our understanding of the relation of fluoride efficacy to brushing time and dentifrice quantity is limited. The aim of this in situ study was to determine how differences in brushing time and dentifrice quantity influence (i) fluoride distribution immediately after brushing, (ii) clearance of fluoride in saliva, (iii) enamel fluoride uptake (EFU) and (iv) enamel strengthening, via the increase in surface microhardness. The study compared brushing times of 30, 45, 60, 120 and 180 s with 1.

Patients' anxiety and expectations: how they influence family physicians' decisions to order cancer screening tests.

Objective: To compare the influence of physicians' recommendations and patients' anxiety or expectations on the decision to order four cancer screening tests in clinical situations where guidelines were equivocal: screening for prostate cancer with prostate-specific antigen for men older than 50; breast cancer screening with mammography for women 40 to 49; colorectal cancer screening with fecal occult blood testing; and colorectal cancer screening with colonoscopy for patients older than 40.

Design: Cross-sectional mailed survey with clinical vignettes.

Setting: British Columbia, Alberta, Ontario, Quebec, and Prince Edward Island.

Predictors of self-reported noncompliance with antihypertensive drug treatment: a prospective cohort study.

Background: Persistence and compliance are different aspects of the broader concept of adherence to drug treatment. In a prior study, determinants of nonpersistence in a group of patients newly prescribed antihypertensive medications were examined.

Objective: To determine noncompliance among those who were persistent with therapy.

What influences family physicians' cancer screening decisions when practice guidelines are unclear or conflicting?

Objectives: To determine (a) the respondents' perceptions of 4 unclear or conflicting cancer screening guidelines: prostate-specific antigen (PSA) for men over 50, mammography for women 40-49, colorectal screening by fecal occult blood testing (FOBT), and colonoscopy for patients over 40; and (b) the influence of various factors on the decision to order these tests.

Study Design: National Canadian mail survey of randomly selected family physicians.

Population: Family physicians in active practice (n=565) selected from rural and urban family medicine sites in 5 provinces representing the main regions in Canada.

Determinants of discontinuation of new courses of antihypertensive medications.

Discontinuation of medication use constitutes a major barrier to adequate control of high blood pressure. We examined the effect of an array of potential predisposing, enabling and reinforcing factors on the discontinuation of newly prescribed antihypertensive medications. We conducted a prospective cohort study through a network of 173 pharmacies across Canada where were identified individuals newly prescribed an antihypertensive monotherapy.

Making decisions about cancer screening when the guidelines are unclear or conflicting.

Objective: Our purpose was to determine the factors involved in the cancer screening decisions of family physicians in situations where the clinical practice guidelines are unclear or conflicting as opposed to when they are clear and uncontroversial.

Study Design: We analyzed discussions with focus groups using a constant comparative approach.

Population: A total of 73 family physicians in active practice participated in 10 focus groups (1 urban group and 1 rural group in each of 5 Canadian provinces).

Tolerability of antihypertensive drugs in a community-based setting.

Background: Outside the experimental environment of clinical trials, the tolerability of angiotensin-converting enzyme inhibitors (ACEIs), calcium channel blockers (CCBs), and the angiotensin II antagonist losartan has not been compared.

Objectives: The purpose of this study was to estimate, in current clinical practice, the 3-month cumulative incidence of side effects among first-time users of losartan, ACEIs, and CCBs for hypertension.

Methods: We conducted a prospective cohort study through a network of 173 pharmacies across Canada to identify patients with hypertension who were newly prescribed monotherapy with losartan, an ACEI, or a CCB.

What factors determine whether individuals found to have hypercholesterolaemia at mass screening accept advice to visit their physician.

Objective: This study aims to identify the determinants of compliance with the recommendation to visit a physician for advice which was given to individuals whose cholesterolemia was > 6.2 mmol/l at mass screening for risk factors of cardiovascular diseases.

Methods: Data were collected from 1144 adults found to be hypercholesterolemic during a screening programme in 54 work sites and 29 public areas and contacted by phone two to six months later.

Communication between family physicians and oncologists: qualitative results of an exploratory study.

Objective: To study communication between family physicians (FPs) and oncologists, and to look at the factors that may influence FP involvement in cancer care.

Design: This survey design uses a qualitative methodology, where the data are analyzed using a modified grounded theory approach.

Setting: This was a multisite study using 14 focus groups of FPs, followed by structured telephone interviews with 116 FPs in 6 different Canadian provinces.

The concept mapping method. An alternative to focus group inquiry in general practice.

Background: The concept mapping rationale and process are explained step by step. The concept mapping method produces a two dimensional conceptual map of ideas produced by the group which can be analysed at the level of individual statements, clusters of statements, and groups of similar clusters. An example of concept mapping conducted with four general practitioner (GP) groups from different practice types and demographic locations is provided.

Medical conditions and the risk of motor vehicle crashes in men.

Objective: To determine whether men aged 45 to 70 years with any medical condition are at an increased risk of involvement as drivers in police-reported motor vehicle crashes.

Design: Case-control study.

Setting: Province-wide population-based sampling.