Online Fault Classification in HPC Systems through Machine Learning

As High-Performance Computing (HPC) systems strive towards the exascale goal, studies suggest that they will experience excessive failure rates. For this reason, detecting and classifying faults in HPC systems as they occur and initiating corrective actions before they can transform into failures will be essential for continued operation. In this paper, we propose a fault classification method for HPC systems based on machine learning that has been designed specifically to operate with live streamed data. We cast the problem and its solution within realistic operating constraints of online use. Our results show that almost perfect classification accuracy can be reached for different fault types with low computational overhead and minimal delay. We have based our study on a local dataset, which we make publicly available, that was acquired by injecting faults to an in-house experimental HPC system.Comment: Accepted for publication at the Euro-Par 2019 conferenc

Ghrelin regulates proliferation and differentiation of osteoblastic cells

Abstract It has previously been reported that growth hormone secretagogues (GHS) may have a role in the regulation of bone metabolism in animals and humans. In this study we evaluated the effect of ghrelin, the endogenous ligand of GHS receptors, on the proliferation rate and on osteoblast activity in primary cultures of rat calvaria osteoblasts. In the same experiments, we compared the effects of ghrelin with those of hexarelin (HEXA) and EP-40737, two synthetic GHS with different characteristics. Both ghrelin and HEXA (10(-11)-10(-8) M) significantly stimulated osteoblast proliferation at low concentrations (10(-10) M). Surprisingly, EP-40737 demonstrated an antiproliferative effect at 10(-9)-10(-8) M, whereas lower concentrations had no effect on cell proliferation. Ghrelin and HEXA significantly increased alkaline phosphatase (ALP) and osteocalcin (OC) production. At variance with these peptides, EP-40737 did not significantly stimulate ALP and OC. The mRNA for GHS-R1a receptors and the corresponding protein were detected in calvarial osteoblasts by RT-PCR and Western blot respectively, indicating that ghrelin and GHS may bind and activate this specific receptor. We conclude that endogenous ghrelin and synthetic GHS modulate proliferation and differentiation of rat osteoblasts, probably by acting on their specific receptor

Flow chamber analysis of size effects in the adhesion of spherical particles

The non-specific adhesion of spherical micro- and nano-particles to a cell substrate is investigated in a parallel plate flow chamber. Differently from prior in-vitro analyses, the total volume of the particles injected into the flow chamber is kept fixed whilst the particle diameter is changed in the range 0.5–10 μm. It is shown that: (i) the absolute number of particles adherent to the cell layer per unit surface decreases with the size of the particle as d−1.7; (ii) the volume of the particles adherent per unit surface increases with the size of the particles as d+1.3. From these results and considering solely non-specific particles, the following hypothesis are generated (i) use the smallest possible particles in biomedical imaging and (ii) use the largest possible particles in drug delivery

Elastin-like-recombinamers multilayered nanofibrous scaffolds for cardiovascular applications

Producción CientíficaCoronary angioplasty is the most widely used technique for removing atherosclerotic plaques in blood vessels. The regeneration of the damaged intima layer after this treatment is still one of the major challenges in the field of cardiovascular tissue engineering. Different polymers have been used in scaffold manufacturing in order to improve tissue regeneration. Elastin-mimetic polymers are a new class of molecules that have been synthesized and used to obtain small diameter fibers with specific morphological characteristics. Elastin-like polymers produced by recombinant techniques and called elastin-like recombinamers (ELRs) are particularly promising due to their high degree of functionalization. Generally speaking, ELRs can show more complex molecular designs and a tighter control of their sequence than other chemically synthetized polymers Rodriguez Cabello et al (2009 Polymer 50 5159–69, 2011 Nanomedicine 6 111–22). For the fabrication of small diameter fibers, different ELRs were dissolved in 2,2,2-fluoroethanol (TFE). Dynamic light scattering was used to identify the transition temperature and get a deep characterization of the transition behavior of the recombinamers. In this work, we describe the use of electrospinning technique for the manufacturing of an elastic fibrous scaffold; the obtained fibers were characterized and their cytocompatibility was tested in vitro. A thorough study of the influence of voltage, flow rate and distance was carried out in order to determine the appropriate parameters to obtain fibrous mats without beads and defects. Moreover, using a rotating mandrel, we fabricated a tubular scaffold in which ELRs containing different cell adhesion sequences (mainly REDV and RGD) were collected. The stability of the scaffold was improved by using genipin as a crosslinking agent. Genipin-ELRs crosslinked scaffolds show a good stability and fiber morphology. Human umbilical vein endothelial cells were used to assess the in vitro bioactivity of the cell adhesion domains within the backbone of the ELRs.2018-08-0

Ischemic heart disease pathophysiology paradigms overview. from plaque activation to microvascular dysfunction

Ischemic heart disease still represents a large burden on individuals and health care resources worldwide. By conventions, it is equated with atherosclerotic plaque due to flow-limiting obstruction in large–medium sized coronary arteries. However, clinical, angiographic and autoptic findings suggest a multifaceted pathophysiology for ischemic heart disease and just some cases are caused by severe or complicated atherosclerotic plaques. Currently there is no well-defined assessment of ischemic heart disease pathophysiology that satisfies all the observations and sometimes the underlying mechanism to everyday ischemic heart disease ward cases is misleading. In order to better examine this complicated disease and to provide future perspectives, it is important to know and analyze the pathophysiological mechanisms that underline it, because ischemic heart disease is not always determined by atherosclerotic plaque complication. Therefore, in order to have a more complete comprehension of ischemic heart disease we propose an overview of the available pathophysiological paradigms, from plaque activation to microvascular dysfunction

Prevention of cardiovascular disease. screening for magnesium deficiency

Magnesium is an essential mineral naturally present in the human body, where it acts as cofactor in several enzymatic reactions. Magnesium is a key cardiovascular regulator, which maintains electrical, metabolic, and vascular homeostasis. Moreover, magnesium participates in inflammation and oxidative processes. In fact, magnesium deficiency is involved in the pathophysiology of arterial hypertension, diabetes mellitus, dyslipidemia, metabolic syndrome, endothelial dysfunction, coronary artery disease, cardiac arrhythmias, and sudden cardiac death. In consideration of the great public-health impact of cardiovascular disease, the recognition of the negative effects of magnesium deficiency suggests the possible role of hypomagnesaemia as cardiovascular risk factor and the use of serum magnesium level for the screening and prevention of cardiovascular risk factors and cardiovascular diseases. Moreover, it might help with the identification of new therapeutical strategies for the management of cardiovascular disease through magnesium supplementation

Local/topical antibiotics for peri-implantitis treatment: a systematic review

Most studies indicate that the mechanical removal of the bacterial biofilm from the implant surface is the central goal of peri-implantitis therapy. However, controversial results in the treatment of peri-implantitis have led to the consideration of additional strategies that include surgical approaches and chemical adjuvants. Local/topical antibiotics, such as minocycline, azithromycin, tetracycline, amoxicillin, doxycycline, and metronidazole, may improve the efficacy of the definitive treatment of the disease, but the lack of conclusive findings prevents their use in clinical practice. This systematic review aimed to evaluate the effect of local/topical antibiotics for peri-implantitis treatment. Randomised controlled studies (RCT) on patients with peri-implantitis and comparing the efficacy of local/topical antibiotics vs. placebo or mechanical debridement were included. A systematic search strategy was carried out using three registered databases (PubMed, Web of Science, and Scopus). RoB2 was used to assess risk of bias. Five RCTs were identified (n = 250 patients and 333 implants). Contrast results emerged among the included studies, and a high heterogeneity level was observed. Risk of bias revealed some concerns for three studies out of five, while one study was judged at high risk. Only one study analysed the limitations of its findings. Overall, local antibiotic use can be considered a valid approach in the treatment of peri-implantitis. Therefore, future long-term clinical trials with standardised protocols and antibiotics with similar biological activity profiles should be tested to achieve a valid and definitive conclusion

Endothelial dysfunction and renal fibrosis in endotoxemia-induced oliguric kidney injury: possible role of LPS binding protein

The pathophysiology of endotoxemia-induced acute kidney injury (AKI) is characterized by an intense activation of the host immune system and renal resident cells by lipopolysaccharide (LPS) and derived proinflammatory products. However, the occurrence of renal fibrosis in this setting has been poorly investigated. The aim of the present study was to investigate the possible association between endothelial dysfunction and acute development of tissue fibrosis in a swine model of LPS-induced AKI. Moreover, we studied the possible effects of coupled plasma filtration adsorption (CPFA) in this setting

Design, structural and functional characterization of a Temporin-1b analog active against Gram-negative bacteria

Background Temporins are small antimicrobial peptides secreted by the Rana temporaria showing mainly activity against Gram-positive bacteria. However, different members of the temporin family, such as Temporin B, act in synergy also against Gram-negative bacteria. With the aim to develop a peptide with a wide spectrum of antimicrobial activity we designed and analyzed a series of Temporin B analogs. Methods Peptides were initially obtained by Ala scanning on Temporin B sequence; antimicrobial activity tests allowed to identify the TB-G6A sequence, which was further optimized by increasing the peptide positive charge (TB-KKG6A). Interactions of this active peptide with the LPS of E. coli were investigated by CD, fluorescence and NMR. Results TB-KKG6A is active against Gram-positive and Gram-negative bacteria at low concentrations. The peptide strongly interacts with the LPS of Gram-negative bacteria and folds upon interaction into a kinked helix. Conclusion Our results show that it is possible to widen the activity spectrum of an antimicrobial peptide by subtle changes of the primary structure. TB-KKG6A, having a simple composition, a broad spectrum of antimicrobial activity and a very low hemolytic activity, is a promising candidate for the design of novel antimicrobial peptides. General significance The activity of antimicrobial peptides is strongly related to the ability of the peptide to interact and break the bacterial membrane. Our studies on TB-KKG6A indicate that efficient interactions with LPS can be achieved when the peptide is not perfectly amphipathic, since this feature seems to help the toroidal pore formation process

Numerical Modeling of Fluid Flow in Solid Tumors

A mathematical model of interstitial fluid flow is developed, based on the application of the governing equations for fluid flow, i.e., the conservation laws for mass and momentum, to physiological systems containing solid tumors. The discretized form of the governing equations, with appropriate boundary conditions, is developed for a predefined tumor geometry. The interstitial fluid pressure and velocity are calculated using a numerical method, element based finite volume. Simulations of interstitial fluid transport in a homogeneous solid tumor demonstrate that, in a uniformly perfused tumor, i.e., one with no necrotic region, because of the interstitial pressure distribution, the distribution of drug particles is non-uniform. Pressure distribution for different values of necrotic radii is examined and two new parameters, the critical tumor radius and critical necrotic radius, are defined. Simulation results show that: 1) tumor radii have a critical size. Below this size, the maximum interstitial fluid pressure is less than what is generally considered to be effective pressure (a parameter determined by vascular pressure, plasma osmotic pressure, and interstitial osmotic pressure). Above this size, the maximum interstitial fluid pressure is equal to effective pressure. As a consequence, drugs transport to the center of smaller tumors is much easier than transport to the center of a tumor whose radius is greater than the critical tumor radius; 2) there is a critical necrotic radius, below which the interstitial fluid pressure at the tumor center is at its maximum value. If the tumor radius is greater than the critical tumor radius, this maximum pressure is equal to effective pressure. Above this critical necrotic radius, the interstitial fluid pressure at the tumor center is below effective pressure. In specific ranges of these critical sizes, drug amount and therefore therapeutic effects are higher because the opposing force, interstitial fluid pressure, is low in these ranges