Particle resuspension: challenges and perspectives for future models

International audienceUsing what has become a celebrated catchphrase, Philip W. Anderson once wrote that "more is different" (Science, Vol. 177, Issue 4047, pp. 393-396, 1972). First formulated in the context of condensed matter, this statement carries far beyond the sole limits of solid-state physics. It emphasizes that collective behavior can be more than the mere sum of what happens for elementary constituents or the mere collation of the evolution of each degree of freedom. Said otherwise, complex phenomena can arise out of the interplay between multiple sub-phenomena each of which can be relatively simple. The process of particle resuspension, in which discrete particles adhering on a surface are pulled off and carried away by a fluid flow, is another example involving a web of phenomena pertaining to fluid mechanics, particle dynamics and interface chemistry whose crosseffects create an intricate topic. The purpose of this review is to analyze the physics at play in particle resuspension in order to bring insights into the rich complexity of this common but challenging concern. Following the more-is-different vision, this is performed by starting from a range of practical observations and experimental data. We then work our way through the investigation of the key mechanisms which play a role in the overall process. In turn, these mechanisms reveal an array of fundamental interactions, such as particle-fluid, particle-particle and particle-surface, whose combined effects create the tapestry of current applications. At the core of this analysis are descriptions of these physical phenomena and the different ways through which they are intertwined to build up various models used to provide quantitative assessment of particle resuspension. The physics of particle resuspension implies to hold together processes occurring at extremely different space and time scales and models are key in providing a single vehicle to lead us through such multiscale journeys. This raises questions on what makes up a model and one objective of the present work is to clarify the essence of a modeling approach. In spite of its ubiquitous nature, particle resuspension is still at the early stages of developments. Many extensions need to be worked out and revisiting the art of modeling is not a moot point. The need to consider more complex objects than small and spherical particles and, moreover, to come up with unified descriptions of mono-and multilayer resuspension put the emphasis on solid model foundations if we are to go beyond current limits. This is very much modeling in the making and new ideas are proposed to stimulate interest into this everyday but challenging issue in physics

Evaluation of chronic lymphocytic leukemia by oligonucleotide-based microarray analysis uncovers novel aberrations not detected by FISH or cytogenetic analysis

<p>Abstract</p> <p>Background</p> <p>Cytogenetic evaluation is a key component of the diagnosis and prognosis of chronic lymphocytic leukemia (CLL). We performed oligonucleotide-based comparative genomic hybridization microarray analysis on 34 samples with CLL and known abnormal karyotypes previously determined by cytogenetics and/or fluorescence <it>in situ </it>hybridization (FISH).</p> <p>Results</p> <p>Using a custom designed microarray that targets >1800 genes involved in hematologic disease and other malignancies, we identified additional cryptic aberrations and novel findings in 59% of cases. These included gains and losses of genes associated with cell cycle regulation, apoptosis and susceptibility loci on 3p21.31, 5q35.2q35.3, 10q23.31q23.33, 11q22.3, and 22q11.23.</p> <p>Conclusions</p> <p>Our results show that microarray analysis will detect known aberrations, including microscopic and cryptic alterations. In addition, novel genomic changes will be uncovered that may become important prognostic predictors or treatment targets for CLL in the future.</p

Racial differences in systemic sclerosis disease presentation: a European Scleroderma Trials and Research group study

Objectives. Racial factors play a significant role in SSc. We evaluated differences in SSc presentations between white patients (WP), Asian patients (AP) and black patients (BP) and analysed the effects of geographical locations.Methods. SSc characteristics of patients from the EUSTAR cohort were cross-sectionally compared across racial groups using survival and multiple logistic regression analyses.Results. The study included 9162 WP, 341 AP and 181 BP. AP developed the first non-RP feature faster than WP but slower than BP. AP were less frequently anti-centromere (ACA; odds ratio (OR) = 0.4, P &lt; 0.001) and more frequently anti-topoisomerase-I autoantibodies (ATA) positive (OR = 1.2, P = 0.068), while BP were less likely to be ACA and ATA positive than were WP [OR(ACA) = 0.3, P &lt; 0.001; OR(ATA) = 0.5, P = 0.020]. AP had less often (OR = 0.7, P = 0.06) and BP more often (OR = 2.7, P &lt; 0.001) diffuse skin involvement than had WP.AP and BP were more likely to have pulmonary hypertension [OR(AP) = 2.6, P &lt; 0.001; OR(BP) = 2.7, P = 0.03 vs WP] and a reduced forced vital capacity [OR(AP) = 2.5, P &lt; 0.001; OR(BP) = 2.4, P &lt; 0.004] than were WP. AP more often had an impaired diffusing capacity of the lung than had BP and WP [OR(AP vs BP) = 1.9, P = 0.038; OR(AP vs WP) = 2.4, P &lt; 0.001]. After RP onset, AP and BP had a higher hazard to die than had WP [hazard ratio (HR) (AP) = 1.6, P = 0.011; HR(BP) = 2.1, P &lt; 0.001].Conclusion. Compared with WP, and mostly independent of geographical location, AP have a faster and earlier disease onset with high prevalences of ATA, pulmonary hypertension and forced vital capacity impairment and higher mortality. BP had the fastest disease onset, a high prevalence of diffuse skin involvement and nominally the highest mortality

Ethanol affects vascular endothelial growth factor and its receptors in coronary microvascular endothelial cells

Background and Purpose: Cardiovascular disease is the leading cause of death in the United States. Moderate alcohol consumption has a cardiovascular protective effect, part of which is mediated by positive effects on high density lipoproteins (HDL). However, these effects only account for about 50% of the cardiovascular protective effects of ethanol. The endothelium is a key player in development of atherosclerosis, and many endothelial functions are controlled by vascular endothelial growth factor (VEGF). Ethanol increases VEGF and its receptors in some systems, but the effects of ethanol on the VEGF system in endothelial cells are not known. Accordingly, the purpose of the study is to examine the influence of ethanol on the expression of VEGF and VEGF receptors (VEGFR) in porcine coronary microvascular endothelial cells (PCMEC). Methods: PCMEC were exposed to one of two ethanol concentrations or no ethanol as a control (0, 10, or 25 mM) and four durations (0.5, 2, 4, or 8 h). VEGF and VEGFR proteins were analyzed quantitatively with ELISA and Western Blot techniques, respectively. VEGFR proteins were also analyzed qualitatively with scanning laser confocal microscopy. Results: With increasing ethanol concentrations, protein levels of VEGF (p=0.006) and VEGFR-1 (p=0.0007) increased significantly, whereas VEGFR-2 decreased significantly (p=0.0492). Increasing duration of ethanol exposure caused VEGF protein levels to increase (p< 0.0001), but had no effect on either VEGFR-1 or VEGFR-2 (p=0.564 and p=0.475, respectively). Discussion: We conclude that ethanol at physiologically relevant concentrations can increase VEGF and VEGFR-1 in PCMEC. VEGF and VEGFR-1 are involved in endothelial maintenance and repair, which can attenuate the atherosclerotic process, and may be involved in the cardiovascular protective effects of moderate alcohol consumption

Particle resuspension: challenges and perspectives for future models

International audienceUsing what has become a celebrated catchphrase, Philip W. Anderson once wrote that "more is different" (Science, Vol. 177, Issue 4047, pp. 393-396, 1972). First formulated in the context of condensed matter, this statement carries far beyond the sole limits of solid-state physics. It emphasizes that collective behavior can be more than the mere sum of what happens for elementary constituents or the mere collation of the evolution of each degree of freedom. Said otherwise, complex phenomena can arise out of the interplay between multiple sub-phenomena each of which can be relatively simple. The process of particle resuspension, in which discrete particles adhering on a surface are pulled off and carried away by a fluid flow, is another example involving a web of phenomena pertaining to fluid mechanics, particle dynamics and interface chemistry whose crosseffects create an intricate topic. The purpose of this review is to analyze the physics at play in particle resuspension in order to bring insights into the rich complexity of this common but challenging concern. Following the more-is-different vision, this is performed by starting from a range of practical observations and experimental data. We then work our way through the investigation of the key mechanisms which play a role in the overall process. In turn, these mechanisms reveal an array of fundamental interactions, such as particle-fluid, particle-particle and particle-surface, whose combined effects create the tapestry of current applications. At the core of this analysis are descriptions of these physical phenomena and the different ways through which they are intertwined to build up various models used to provide quantitative assessment of particle resuspension. The physics of particle resuspension implies to hold together processes occurring at extremely different space and time scales and models are key in providing a single vehicle to lead us through such multiscale journeys. This raises questions on what makes up a model and one objective of the present work is to clarify the essence of a modeling approach. In spite of its ubiquitous nature, particle resuspension is still at the early stages of developments. Many extensions need to be worked out and revisiting the art of modeling is not a moot point. The need to consider more complex objects than small and spherical particles and, moreover, to come up with unified descriptions of mono-and multilayer resuspension put the emphasis on solid model foundations if we are to go beyond current limits. This is very much modeling in the making and new ideas are proposed to stimulate interest into this everyday but challenging issue in physics

Development of a high-density pericentromeric region BAC clone set for the detection and characterization of small supernumerary marker chromosomes by array CGH

Small supernumerary marker chromosomes are centric chromosomal segments that, by definition, cannot be characterized unambiguously by conventional chromosome banding. Marker chromosomes are of particular interest in clinical cytogenetics because they are nearly 10 times more frequent in individuals with mental retardation (0.426%) than in the normal population (0.043%). However, they are often found in only a small percentage of cells, making them difficult to detect and characterize in a diagnostic setting. We designed, constructed, and employed a bacterial artificial chromosome (BAC)-based microarray to demonstrate the utility of array-based comparative genomic hybridization (array CGH) for detecting and characterizing marker chromosomes in clinical diagnostic specimens. We constructed a high-density microarray using 974 BAC clones that were mapped by fluorescence in situ hybridization and cover approximately 5 Mb of the most proximal unique sequence adjacent to the centromere on all 43 unique pericentromeric regions of the human genome (excluding the acrocentric short arms). This array was used to further characterize 20 previously identified marker chromosomes that were originally found with either conventional chromosome analysis or a targeted microarray. The enhanced coverage of this pericentromeric array not only identified the chromosomal origin of each marker in 15 cases, it also distinguished between the involvement of the short arm and/or the long arm of each chromosome, defined the sizes of many of the markers, and revealed complex rearrangements or multiple markers in single individuals. However, in five cases, the markers could not be identified by this assay, most likely because of very low levels of mosaicism and/or their small size and lack of detectable euchromatin. The expanded coverage of the pericentromeric regions represented on the array was adequate to refine the breakpoints in two-thirds of all cases in which a marker chromosome was identified by this assay. This study demonstrates the utility of array CGH in the detection and characterization of mosaic marker chromosomes. Because approximately one-third of the markers characterized in this study involved more unique sequence than that represented on this array, additional pericentromeric coverage may be even more valuable. We anticipate that this will allow detailed characterization of small supernumerary marker chromosomes that will greatly facilitate phenotype/genotype correlations and play a valuable role in the diagnosis and medical management of both pre- and postnatal cases in which marker chromosomes have been identified

Contamination du bassin versant de l'ORGE par les micropolluants et effets toxiques associés

Depuis 2007, le bassin versant (BV) de l'Orge a été retenu comme site atelier par le PIREN Seine. Ce BV périurbain est, en effet, soumis à une pression anthropique importante, notamment dans sa partie aval fortement urbanisée. L'objectif de ces travaux était de poursuivre létude initiée en 2007, qui visait à caractériser la contamination du BV par différentes familles de micropolluants métalliques et organiques (dont plusieurs composés classés comme substances prioritaires par la DCE)

Incidence and risk factors for gangrene in patients with systemic sclerosis from the EUSTAR cohort

Objective: In patients with SSc, peripheral vasculopathy can promote critical ischaemia and gangrene. The aim of this study was to investigate the prevalence, incidence and risk factors for gangrene in the EUSTAR cohort. Methods: We included patients from the EUSTAR database fulfilling the ACR 1980 or the ACR/EULAR 2013 classification criteria for SSc, with at least one visit recording data on gangrene. Centres were asked for supplementary data on traditional cardiovascular risk factors. We analysed the cross-sectional relationship between gangrene and its potential risk factors by univariable and multivariable logistic regression. Longitudinal data were analysed by Cox proportional hazards regression. Results: 1757 patients were analysed (age 55.9 [14.5] years, disease duration 7.9 [10.3] years, male sex 16.7%, 24.6% diffuse cutaneous subset [dcSSc]). At inclusion, 8.9% of patients had current or previous digital gangrene, 16.1% had current digital ulcers (DUs) and 42.7% had ever had DUs (current or previous). Older age, DUs ever and dcSSc were statistically significant risk factors for gangrene in the cross-sectional multivariable model. During a median follow-up of 13.1 months, 16/771 (0.9%) patients developed gangrene. All 16 patients who developed gangrene had previously had DUs and gangrene. Further risk factors for incident gangrene were the dcSSc subset and longer disease duration. Conclusion: In unselected SSc patients, gangrene occurs in about 9% of SSc patients. DUs ever and, to a lesser extent, the dcSSc subset are strongly and independently associated with gangrene, while traditional cardiovascular risk factors could not be identified as risk factors

More Than 50 Percent Reduction in LDL Cholesterol in Patients With Target LDL <70 mg/dL After a Stroke

International audienceBACKGROUND: Whether a strategy to target an LDL (low-density lipoprotein) cholesterol 50% from baseline rather than 50% LDL cholesterol reduction from baseline during the trial had a higher baseline LDL cholesterol and a lower LDL cholesterol achieved as compared to patients who had 50% LDL reduction had a significant reduction in the primary outcome as compared to the higher target group (hazard ratio, 0.61 [95% CI, 0.43–0.88]; P =0.007) and patients with <50% LDL reduction from baseline had little reduction (hazard ratio, 0.96 [95% CI, 0.73–1.26]; P =0.75). CONCLUSIONS: In this post hoc analysis of the TST trial, targeting an LDL cholesterol of <70 mg/dL reduced the risk of primary outcome compared with 100±10 mg/dL provided LDL cholesterol reduction from baseline was superior to 50%, thereby suggesting that the magnitude of LDL cholesterol reduction was as important to consider as the target level to achieve. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT01252875. URL: https://clinicaltrialsregister.eu ; Unique identifier: EUDRACT2009-A01280-57.gov; Unique identifier: NCT01252875. URL: https://clinicaltrialsregister.eu; Unique identifier: EUDRACT2009-A01280-57.URL: https://www