Multi-Scale Vector-Ridge-Detection for Perceptual Organization Without Edges

We present a novel ridge detector that finds ridges on vector fields. It is designed to automatically find the right scale of a ridge even in the presence of noise, multiple steps and narrow valleys. One of the key features of such ridge detector is that it has a zero response at discontinuities. The ridge detector can be applied to scalar and vector quantities such as color. We also present a parallel perceptual organization scheme based on such ridge detector that works without edges; in addition to perceptual groups, the scheme computes potential focus of attention points at which to direct future processing. The relation to human perception and several theoretical findings supporting the scheme are presented. We also show results of a Connection Machine implementation of the scheme for perceptual organization (without edges) using color

Categorization of Thermoacoustic Modes in an Ideal Resonator with Phasor Diagrams

A recent study (Yong, Silva, and Polifke, Combust. Flame 228 (2021)) proposed the use of phasor diagrams to categorize marginally stable modes in an ideal resonator with a compact, velocity-sensitive flame. Modes with velocity phasors that reverse direction across the flame were categorized as ITA modes. The present study extends this concept to growing and decaying modes. In other words, with the method proposed, it is possible to distinguish whether a given thermoacoustic mode -- regardless of its stability -- should be categorized as acoustic or ITA. The method proposed does not rely on any parametric sweep, but on the angle relating the velocity phasors across the flame. This method of categorization reveals distinct regions in the complex plane where acoustic and ITA eigenfrequencies are localized. Additionally, we analyze the medium oscillation at the flame location to construct a physically intuitive understanding of the proposed categorization method.Comment: to be published in Combustion and Flam

Complementary and alternative medicine use in oncology: A questionnaire survey of patients and health care professionals

<p>Abstract</p> <p>Background</p> <p>We aimed to investigate the prevalence and predictors of Complementary and Alternative Medicine (CAM) use among cancer patients and non-cancer volunteers, and to assess the knowledge of and attitudes toward CAM use in oncology among health care professionals.</p> <p>Methods</p> <p>This is a cross-sectional questionnaire survey conducted in a single institution in Ireland. Survey was performed in outpatient and inpatient settings involving cancer patients and non-cancer volunteers. Clinicians and allied health care professionals were asked to complete a different questionnaire.</p> <p>Results</p> <p>In 676 participants including 219 cancer patients; 301 non-cancer volunteers and 156 health care professionals, the overall prevalence of CAM use was 32.5% (29.1%, 30.9% and 39.7% respectively in the three study cohorts). Female gender (p < 0.001), younger age (p = 0.004), higher educational background (p < 0.001), higher annual household income (p = 0.001), private health insurance (p = 0.001) and non-Christian (p < 0.001) were factors associated with more likely CAM use. Multivariate analysis identified female gender (p < 0.001), non-Christian (p = 0.001) and private health insurance (p = 0.015) as independent predictors of CAM use. Most health care professionals thought they did not have adequate knowledge (58.8%) nor were up to date with the best evidence (79.2%) on CAM use in oncology. Health care professionals who used CAM were more likely to recommend it to patients (p < 0.001).</p> <p>Conclusions</p> <p>This study demonstrates a similarly high prevalence of CAM use among oncology health care professionals, cancer and non cancer patients. Patients are more likely to disclose CAM usage if they are specifically asked. Health care professionals are interested to learn more about various CAM therapies and have poor evidence-based knowledge on specific oncology treatments. There is a need for further training to meet to the escalation of CAM use among patients and to raise awareness of potential benefits and risks associated with these therapies.</p

Bi-allelic variants in the mitochondrial RNase P subunit PRORP cause mitochondrial tRNA processing defects and pleiotropic multisystem presentations

Human mitochondrial RNase P (mt-RNase P) is responsible for 5' end processing of mitochondrial precursor tRNAs, a vital step in mitochondrial RNA maturation, and is comprised of three protein subunits: TRMT10C, SDR5C1 (HSD10), and PRORP. Pathogenic variants in TRMT10C and SDR5C1 are associated with distinct recessive or x-linked infantile onset disorders, resulting from defects in mitochondrial RNA processing. We report four unrelated families with multisystem disease associated with bi-allelic variants in PRORP, the metallonuclease subunit of mt-RNase P. Affected individuals presented with variable phenotypes comprising sensorineural hearing loss, primary ovarian insufficiency, developmental delay, and brain white matter changes. Fibroblasts from affected individuals in two families demonstrated decreased steady state levels of PRORP, an accumulation of unprocessed mitochondrial transcripts, and decreased steady state levels of mitochondrial-encoded proteins, which were rescued by introduction of the wild-type PRORP cDNA. In mt-tRNA processing assays performed with recombinant mt-RNase P proteins, the disease-associated variants resulted in diminished mitochondrial tRNA processing. Identification of disease-causing variants in PRORP indicates that pathogenic variants in all three subunits of mt-RNase P can cause mitochondrial dysfunction, each with distinct pleiotropic clinical presentations.Peer reviewe

Translation of MT-ATP6 pathogenic variants reveals distinct regulatory consequences from the co-translational quality control of mitochondrial protein synthesis

ddab314Pathogenic variants that disrupt human mitochondrial protein synthesis are associated with a clinically heterogeneous group of diseases. Despite an impairment in oxidative phosphorylation being a common phenotype, the underlying molecular pathogenesis is more complex than simply a bioenergetic deficiency. Currently, we have limited mechanistic understanding on the scope by which a primary defect in mitochondrial protein synthesis contributes to organelle dysfunction. Since the proteins encoded in the mitochondrial genome are hydrophobic and need co-translational insertion into a lipid bilayer, responsive quality control mechanisms are required to resolve aberrations that arise with the synthesis of truncated and misfolded proteins. Here, we show that defects in the OXA1L-mediated insertion of MT-ATP6 nascent chains into the mitochondrial inner membrane are rapidly resolved by the AFG3L2 protease complex. Using pathogenic MT-ATP6 variants, we then reveal discrete steps in this quality control mechanism and the differential functional consequences to mitochondrial gene expression. The inherent ability of a given cell type to recognize and resolve impairments in mitochondrial protein synthesis may in part contribute at the molecular level to the wide clinical spectrum of these disorders.Peer reviewe

Angiotensin receptor blockers and risk of dementia: cohort study in UK Clinical Practice Research Datalink.

AIMS: This was a cohort study to evaluate whether individuals exposed to angiotensin receptor blockers have a reduced risk of dementia compared with those exposed to angiotensin-converting enzyme inhibitors. METHODS: The study included new users of angiotensin receptor blockers or angiotensin-converting enzyme inhibitors (from 1995 to 2010) from UK primary care practices contributing to the Clinical Research Practice Datalink. The association between exposure to angiotensin receptor blockers and the risk of incident dementia was analysed using a Cox model, adjusting for age, sex, body mass index, diabetes, hypertension, heart failure, statin use, socioeconomic status, alcohol, smoking, number of consultations and calendar year. RESULTS: A total of 426 089 persons were included in the primary analysis, with 45 541 persons exposed to angiotensin receptor blockers and the remainder to angiotensin-converting enzyme inhibitors. The total number of new diagnoses of dementia was 6517. There was weak evidence of a decreased risk of dementia with exposure to angiotensin receptor blockers, with follow-up beginning at 1 year after the start of treatment (adjusted hazard ratio 0.92, 95% confidence interval 0.85-1.00). An analysis restricted to the first 12 months after the index date showed a larger effect on dementia risk (adjusted hazard ratio 0.60, 95% confidence interval 0.50-0.72). CONCLUSIONS: A small reduction in dementia risk was seen with angiotensin receptor blockers in comparison to angiotensin-converting enzyme inhibitors. However, the strongest association was seen in early follow-up, suggesting that the inverse association is unlikely to be causal, but instead reflects other important but unmeasured differences between angiotensin receptor blocker and angiotensin-converting enzyme inhibitor users

A scaling law for distinct electrocaloric cooling performance in low-dimensional organic, relaxor and anti-ferroelectrics.

Electrocaloric (EC) materials show promise in eco-friendly solid-state refrigeration and integrable on-chip thermal management. While direct measurement of EC thin-films still remains challenging, a generic theoretical framework for quantifying the cooling properties of rich EC materials including normal-, relaxor-, organic- and anti-ferroelectrics is imperative for exploiting new flexible and room-temperature cooling alternatives. Here, we present a versatile theory that combines Master equation with Maxwell relations and analytically relates the macroscopic cooling responses in EC materials with the intrinsic diffuseness of phase transitions and correlation characteristics. Under increased electric fields, both EC entropy and adiabatic temperature changes increase quadratically initially, followed by further linear growth and eventual gradual saturation. The upper bound of entropy change (∆Smax) is limited by distinct correlation volumes (V cr ) and transition diffuseness. The linearity between V cr and the transition diffuseness is emphasized, while ∆Smax = 300 kJ/(K.m3) is obtained for Pb0.8Ba0.2ZrO3. The ∆Smax in antiferroelectric Pb0.95Zr0.05TiO3, Pb0.8Ba0.2ZrO3 and polymeric ferroelectrics scales proportionally with V cr-2.2, owing to the one-dimensional structural constraint on lattice-scale depolarization dynamics; whereas ∆Smax in relaxor and normal ferroelectrics scales as ∆Smax ~ V cr-0.37, which tallies with a dipolar interaction exponent of 2/3 in EC materials and the well-proven fractional dimensionality of 2.5 for ferroelectric domain walls

Efficient Generation of iPS Cells from Skeletal Muscle Stem Cells

Reprogramming of somatic cells into inducible pluripotent stem cells generally occurs at low efficiency, although what limits reprogramming of particular cell types is poorly understood. Recent data suggest that the differentiation status of the cell targeted for reprogramming may influence its susceptibility to reprogramming as well as the differentiation potential of the induced pluripotent stem (iPS) cells that are derived from it. To assess directly the influence of lineage commitment on iPS cell derivation and differentiation, we evaluated reprogramming in adult stem cell and mature cell populations residing in skeletal muscle. Our data using clonal assays and a second-generation inducible reprogramming system indicate that stem cells found in mouse muscle, including resident satellite cells and mesenchymal progenitors, reprogram with significantly greater efficiency than their more differentiated daughters (myoblasts and fibroblasts). However, in contrast to previous reports, we find no evidence of biased differentiation potential among iPS cells derived from myogenically committed cells. These data support the notion that adult stem cells reprogram more efficiently than terminally differentiated cells, and argue against the suggestion that “epigenetic memory” significantly influences the differentiation potential of iPS cells derived from distinct somatic cell lineages in skeletal muscle

Turbulent Combustion of Polydisperse Evaporating Sprays with Droplet Crossing: Eulerian Modeling and Validation in the Infinite Knudsen Limit

The accurate simulation of the dynamics of polydisperse evaporating sprays in unsteady gaseous flows with large-scale vortical structures is both a crucial issue for industrial applications and a challenge for modeling and scientific computing. The difficulties encountered by the usual Lagrangian approaches make the use of Eulerian models attractive, aiming at a lower cost and an easier coupling with the carrier gaseous phase. Among these models, the multi-fluid model allows for a detailed description of the polydispersity and size-velocity correlations for droplets of various sizes. The purpose of the present study is twofold. First, we extend the multi-fluid model in order to cope with crossing droplet trajectories by using the quadrature method of moments in velocity phase space conditioned by size. We identify the numerical difficulties and provide dedicated numerical schemes in order to preserve the velocity moment space. Second, we conduct a comparison study and demonstrate the capability of such an approach to capture the dynamics of an evaporating polydisperse spray in a 2-D free jet configuration. We evaluate the accuracy and computational cost of Eulerian models and related discretization schemes vs. Lagrangian solvers and show that, even for finite Stokes number, the standard Eulerian multi-fluid model can be accurate at reasonable cost

Ghrelin induces clock gene expression in the liver of goldfish in vitro via protein kinase C and protein kinase A pathways

International audienceThe liver is the most important link between the circadian system and metabolism. As a food-entrainable oscillator, the hepatic clock needs to be entrained by food-related signals. The objective of the present study was to investigate the possible role of ghrelin (an orexigenic peptide mainly synthesized in the gastrointestinal tract) as an endogenous synchronizer of the liver oscillator in teleosts. To achieve this aim, we first examined the presence of ghrelin receptors in the liver of goldfish. Then, the ghrelin regulation of clock gene expression in the goldfish liver was studied. Finally, the possible involvement of the phospholipase C/ protein kinase C (PLC/ PKC) and adenylate cyclase/protein kinase A (AC/PKA) intracellular signalling pathways was investigated. Ghrelin receptor transcripts, ghs-r1a, are present in the majority of goldfish hepatic cells. Ghrelin induced the mRNA expression of the positive (gbmal1a, gclock1a) and negative (gper genes) elements of the main loop of the molecular clock machinery, as well as grev-erba (auxiliary loop) in cultured liver. These effects were blocked, at least in part, by a ghrelin antagonist. Incubation of liver with a PLC inhibitor (U73122), a PKC activator (phorbol 12-myristate 13-acetate) and a PKC inhibitor (chelerythrine chloride) demonstrated that the PLC/ PKC pathway mediates such ghrelin actions. Experiments with an AC activator (forskolin) and a PKA inhibitor (H89) showed that grev-erba regulation could be due to activation of PKA. Taken together, the present results show for the first time in vertebrates a direct action of ghrelin on hepatic clock genes and support a role for this hormone as a temporal messenger in the entrainment of liver circadian functions