Hybrid RANS/LES simulations of bluff-body flows

A new hybrid RANS/LES approach is proposed. The key feature of this approach is a blending between two eddy-viscosities, one given by the k-epsilon RANS model and the other by the Smagorinsky VMS-LES (variational multiscale LES) closure. The blending is set by a parameter teta: VMS-LES mode is active when teta=0, RANS mode if teta=1, a hybrid mode for 0<theta<1. The proposed hybrid model has been applied to the numerical simulation of the flow around a square cylinder at Re_L=22000. Three different parameters (based on viscosity ratio, time ratio and length ratio) are tested. The results obtained with this new hybrid approach are compared with those obtained using the LNS approach for two different grid resolutions; comparisons with experimental data in the litterature are also provided. The sensitivity of the model to some setting parameters (the inflow value of the turbulent kinetic energy, k_0 and the parameter delta in the approximate wall treatment) is also analysed. The hybrid model has been also applied to the simulation of the flow around a circular cylinder at Re_D=140000.The results are compared with those obtained using the DES approach. Also for this case, comparisons with experimental data in the litterature are provided

Cardiovascular Risk and Mild Thyroid Hormone Deficiency: Are there some Differences in the Elderly?

Subclinical hypothyroidism (sHT) is a clinical condition defined as serum TSH concentration above the upper limit of the reference range in the face of normal free T4 (FT4) and free T3 (FT3) levels. Subclinical hypothyroidism, the prevalence of which increases with age, especially among women, up to almost 20%, encompasses several pathological entities, mainly represented by chronic autoimmune thyroiditis [1,2]. sHT is often associated to symptoms that resembles those of overt hypothyroidism, although to a lesser extent thus, the expression ‘mild thyroid impairment’ or ‘mild thyroid hormone deficiency’ would be more appropriate for defining such a condition [1]. Nonetheless, the term sHT is recognized worldwide and will be utilized in the present editorial. Since 90s, a relationship between sHT and increased cardio-vascular (CV) risk (both heart failure and coronary heart disease events) has been reported, although some experiences suggest that the risk may depend on the degree of TSH elevation [1,3-5]. Moreover, several reports from elderly population (>65 years old) showed that this relationship seems no longer evident in such individuals especially in the oldest old (>85 years old) [6-9]

Strategies for RANS/VMS-LES coupling

A new hybrid RANS/LES approach is proposed. The key feature of this approach is a blending between two eddy-viscosities, one given by the $k-\varepsilon$ RANS model and the other by the Smagorinsky VMS-LES (variational multiscale LES) closure. The blending is set by a parameter $\theta$: VMS-LES mode is active when $\theta=0$, RANS mode if $\theta=1$, a hybrid mode for $0<\theta<1$. The proposed hybrid model has been applied to the numerical simulation of the flow around a square cylinder at $Re_L=22000$. Three different parameters (based on viscosity ratio, time ratio and length ratio) are tested. The results obtained with this new hybrid approach are compared with those obtained using the LNS approach for two different grid resolutions; comparisons with experimental data in the litterature are also provided. The sensitivity of the model to some setting parameters (the inflow value of the turbulent kinetic energy, $k_0$ and the parameter $\delta$ in the approximate wall treatment) is also analysed

Expression of vascular endothelial growth factor (VEGF) in equine sarcoid

Background: Sarcoids are the mostcommon skin tumors in horses, ch aracterized by rare regression, invasiveness and high recurrence following surgical intervention and Delta Papillomaviruses are widely recognized as the causative agents of the disease. In order to gain new insights into equine sarco id development, we have evaluated, in 25 equine sarcoids, by immunohistochemistry and western blotting analysis, the expression levels of VEGF, Ki67 and bcl-2. Moreover, we have measured microvessel density an d specific vessel parameters. Results: All sarcoid samples showed a strong and finely granular cytoplasmatic staining for VEGF in the majority (90%) of keratinocytes, sarcoid fibroblasts and endothelial cells. Numerous small blood vessels, immunostained with Von Willebrand factor, often appeared irregular in shape and without a distinct lumen, with mean values of microvessel area and perimeter lower than normal. Moreover, in all sarcoid samples, Ki67 immunoreactivity was moderately positive in 5 – 10% of dermal sarcoid fibroblasts, while Bcl2 immunoreactivity was detected in 52% of the sarcoid samples, with a weak staining in 20 – 50% of dermal sarcoid fibroblasts. Biochemical analysis was consistent with immunohistochemical results. Conclusions: This study has provided evidence that in equine sarcoid: VEGF was strongly expressed; the increased number of vessels was not associated with their complete maturation, probably leading to a hypoxic condition, which could increase VEGF synthesis; the levels of sarcoid fibroblasts proliferation were very low. Concluding, VEGF may have a role in equine sarcoid development, not only through the increase of angiogenesis, but also through the control of sarcoid fibroblast activity

Identifying prodromal symptoms at high specificity for Parkinson’s disease

IntroductionTo test drugs with the potential to prevent the onset of Parkinson’s disease (PD), it is key to identify individuals in the general population at high risk of developing PD. This is often difficult because most of the clinical markers are non-specific, common in PD but also common in older adults (e.g., sleep problems).ObjectiveWe aimed to identify the clinical markers at high specificity for developing PD by comparing individuals with PD or prodromal PD to healthy controls.MethodsWe investigated motor and non-motor symptoms (Movement Disorder Society Unified Parkinson’s Disease Rating Scale Part 1 and 2 items) in 64 prodromal PD and 422 PD individuals calculating the odds ratios, adjusting for age and gender, for PD and prodromal PD versus 195 healthy controls. Symptoms at high specificity were defined as having an adjusted odds ratio ≥ 6.ResultsConstipation had an adjusted odds ratio, 6.14 [95% CI: 2.94–12.80] showing high specificity for prodromal PD, and speech difficulties had an adjusted odds ratio, 9.61 [95% CI: 7.88–48.81] showing high specificity for PD. The proportion of participants showing these specific markers was moderate (e.g., prevalence of constipation was 43.75% in prodromal PD, and speech difficulties was 33.89% in PD), suggesting these symptoms may make robust predictors of prodromal PD and PD, respectively.DiscussionClinical markers at high specificity for developing PD could be used as tools in the screening of general populations to identify individuals at higher risk of developing PD

Beyond Jacobian-based tasks: Extended set-based tasks for multi-task execution and prioritization

The ability of executing multiple tasks simultaneously is an important feature of redundant robotic systems. As a matter of fact, complex behaviors can often be obtained as a result of the execution of several tasks. Moreover, in safety-critical applications, tasks designed to ensure the safety of the robot and its surroundings have to be executed along with other nominal tasks. In such cases, it is also important to prioritize the former over the latter. In this paper, we formalize the definition of extended set-based tasks, i.e., tasks which can be executed by rendering subsets of the task space asymptotically stable or forward invariant. We propose a mathematical representation of such tasks that allows for the execution of more complex and time-varying prioritized stacks of tasks using kinematic and dynamic robot models alike. We present and analyze an optimization-based framework which is computationally efficient, accounts for input bounds, and allows for the stable execution of time-varying prioritized stacks of extended set-based tasks. The proposed framework is validated using extensive simulations and experiments with robotic manipulators

Undertreatment of breast cancer in the elderly

AIMS: The effect of undertreatment with adjuvant hormonal therapy, chemotherapy or radiation was studied in elderly women with breast cancer. METHODS: A prospectively maintained database was used to identify women undergoing potentially curative surgery between 1997 and 2011. The presentation, pathologic findings, treatment and outcomes of 449 women over 65 were compared to the findings in 1049 younger patients. Moreover, conventionally treated and undertreated elderly patients were identified and their characteristics and outcomes were compared. RESULTS: Both young and old patients presented most frequently with mammographic findings, but older patients presented more frequently with mammographic masses while younger patients presented more frequently with mammographic calcifications. Cancers of older patients were signicantly more favorable than cancers in younger patients with more infiltrating lobular, fewer ductal carcinoma in situ and more frequently estrogen receptor positive and fewer were poorly differentiated. Elderly patients had less axillary surgery, less adjuvant radiation therapy and more hormonal therapy. Fourty-six percent of the 449 elderly patients were undertreated by conventional criteria. Undertreated patients were more frequently in situ, better differentiated, smaller, and more often estrogen receptor positive. Forty-four percent of the undertreated patients died during follow-up without disease recurrence. CONCLUSIONS: Despite undertreatment, local and distant disease-free survival was comparable to patients who were not undertreated

Breast cancer surgery in elderly patients: postoperative complications and survival

AIMS AND BACKGROUND: Old age is associated with comorbidity and decreased functioning which influences treatment decisions in elderly breast cancer patients. The purpose of this study was to identify risk factors for complications after breast cancer surgery in elderly patients, and to assess mortality in patients with postoperative complications. METHODS: We retrospectively considered all female patients aged 65 years and older with invasive and in situ breast cancer who were diagnosed and treated between 1997 and 2012 in the Department of General and Geriatric Surgery of the University of Naples "Federico II". RESULTS AND CONCLUSION: 449 patients received surgery, of whom 18,2% (n = 82) developed one or more postoperative complications. The odds ratio of having postoperative complications show an increase with age, reaching statistical significance only for patients older than 85 [OR 5,75 (95% confidence interval 2,38-14,04); p < 0,001]. Number of concomitant diseases [OR 2,51 (95% CI 1,17 - 5,45); p = 0,01 for 3 or more concomitant diseases] and polypharmacy [OR 16,7 (95% CI 9,12 - 30,58); p < 0,0001) are associated to an increased risk of postoperative complications. Overall survival was worse in patients with postoperative complications [HR 2,06 (95% CI 1,52-2,70), p < 0,001]. This increased risk of mortality is probably due to geriatric parameters such as comorbidity or poor physical function, more than to higher complication rates

Evolution shapes the responsiveness of the D-box enhancer element to light and reactive oxygen species in vertebrates

The circadian clock is a highly conserved cell-autonomous mechanism that directs daily rhythms in most aspects of biology. Daily entrainment by environmental signals, notably light, is essential for its function. However, our understanding of the mechanisms and the evolution of photic entrainment remains incomplete. Fish represent attractive models for exploring how light regulates the circadian clock due to the direct light sensitivity of their peripheral clocks. Central to this property is the light induced expression of clock genes that is mediated by D-box enhancer elements. Here, using zebrafish cells, we reveal that the light responsive D-box enhancer serves as a nuclear target for reactive oxygen species (ROS). We demonstrate that exposure to short wavelengths of visible light triggers increases in ROS levels via NADPH oxidase activity. Elevated ROS activates the JNK and p38 MAP kinases and in turn, induces clock gene expression via the D-box. In blind cavefish and mammals, where peripheral clocks are no longer entrained by direct illumination, ROS levels are still increased upon light exposure. However, in these species ROS no longer induces D-box driven clock gene transcription. Thus, during evolution, alterations in ROS-responsive signal transduction pathways underlie fundamental changes in peripheral clock photoentrainment.Universidad de Ferrara | Ref. FAR2014–201