365 research outputs found

    Small bialgebras with a projection

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    AbstractLet A be a bialgebra with an H-bilinear coalgebra projection over an arbitrary subbialgebra H with antipode. In characteristic zero, we completely describe the bialgebra structure of A whenever H is either f.d. or cosemisimple and the H-coinvariant part R of A is connected with one-dimensional space of primitive elements

    Ergonomics and Workflow Evaluation of Automatic Doppler Angle Technology Implemented in a Diagnostic Ultrasound System

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    AbstractCommonly available Pulsed Wave Doppler (PW) flow velocity measurements for Ultrasound (US) investigation require the operator to manually set the direction of the flow velocity vector along the blood vessel axis on the US image, in order to determine the Doppler angle and then to estimate the real flow velocity. The present work investigates the possibility to implement on a commercially available US system an innovative Automatic Doppler Angle (ADA) Technology by analyzing the best workflow in terms of higher execution speed, lower keystrokes/adjustments helping in the prevention of Work-related Musculoskeletal Disorders (WRMSD) and a Doppler angle correction precision, comparable to the one obtained manually by expert sonographer. Ergonomics and workflow tests, then accuracy and repeatability evaluations of the Doppler velocity measurement, were performed on a portable US system (MyLabAlpha, Esaote S.p.A., Florence, Italy) by an expert sonographer. Ergonomics and workflow Tests were performed to analyze the potential of ADA in terms of reduction of muscular activation applied (by SEMG), number of activations (by cameras optoelectronic system) and time needed using ADA, in comparison to manual procedure. Accuracy and intra-operator repeatability tests of the velocity measurement were performed to evaluate the precision of the obtained PW trace velocity measurements with ADA technology, compared to manual ones. Results provided evidence that ADA tool allowed: a reduction of muscular activation (from 12% for trapezius descendens, to 25% for deltoideus anterior) a lower total number of keystrokes and a reduction of the US scan time of about 56%. The maximal variation between PW Doppler trace velocity measurement set automatically by ADA and set manually by sonographer was 11%. ADA technology can provide a Doppler angle correction precision comparable to the manual one, while decreasing the risk of WRMSD

    Calcium-activated chloride currents in olfactory sensory neurons from mice lacking bestrophin-2

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    none8noOlfactory sensory neurons use a chloride-based signal amplification mechanism to detect odorants. The binding of odorants to receptors in the cilia of olfactory sensory neurons activates a transduction cascade that involves the opening of cyclic nucleotide-gated channels and the entry of Ca2+ into the cilia. Ca2+ activates a Cl- current that produces an efflux of Cl- ions and amplifies the depolarization. The molecular identity of Ca2+-activated Cl- channels is still elusive, although some bestrophins have been shown to function as Ca2+ -activated Cl- channels when expressed in heterologous systems. In the olfactory epithelium, bestrophin-2 (Best2) has been indicated as a candidate for being a molecular component of the olfactory Ca2+-activated Cl- channel. In this study, we have analysed mice lacking Best2. We compared the electrophysiological responses of the olfactory epithelium to odorant stimulation, as well as the properties of Ca2+-activated Cl- currents in wild-type (WT) and knockout (KO) mice for Best2. Our results confirm that Best2 is expressed in the cilia of olfactory sensory neurons, while odorant responses and Ca2+ -activated Cl- currents were not significantly different between WT and KO mice. Thus, Best2 does not appear to be the main molecular component of the olfactory channel. Further studies are required to determine the function of Best2 in the cilia of olfactory sensory neurons. © 2009 The Authors. Journal compilation © 2009 The Physiological Society.openPifferi S.; Dibattista M.; Sagheddu C.; Boccaccio A.; Al Qteishat A.; Ghirardi F.; Tirindelli R.; Menini A.Pifferi, S.; Dibattista, M.; Sagheddu, C.; Boccaccio, A.; Al Qteishat, A.; Ghirardi, F.; Tirindelli, R.; Menini, A

    Spatio-Temporal Vegetation Pixel Classification by Using Convolutional Networks

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    Plant phenology studies rely on long-term monitoring of life cycles of plants. High-resolution unmanned aerial vehicles (UAVs) and near-surface technologies have been used for plant monitoring, demanding the creation of methods capable of locating, and identifying plant species through time and space. However, this is a challenging task given the high volume of data, the constant data missing from temporal dataset, the heterogeneity of temporal profiles, the variety of plant visual patterns, and the unclear definition of individuals' boundaries in plant communities. In this letter, we propose a novel method, suitable for phenological monitoring, based on convolutional networks (ConvNets) to perform spatio-temporal vegetation pixel classification on high-resolution images. We conducted a systematic evaluation using high-resolution vegetation image datasets associated with the Brazilian Cerrado biome. Experimental results show that the proposed approach is effective, overcoming other spatio-temporal pixel-classification strategies

    Diabetes promotes invasive pancreatic cancer by increasing systemic and tumour carbonyl stress in Kras G12D/+mice

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    Background: Type 1 and 2 diabetes confer an increased risk of pancreatic cancer (PaC) of similar magnitude, suggesting a common mechanism. The recent finding that PaC incidence increases linearly with increasing fasting glucose levels supports a central role for hyperglycaemia, which is known to cause carbonyl stress and advanced glycation end-product (AGE) accumulation through increased glycolytic activity and non-enzymatic reactions. This study investigated the impact of hyperglycaemia on invasive tumour development and the underlying mechanisms involved. Methods: Pdx1-Cre;LSL-Kras G12D/+ mice were interbred with mitosis luciferase reporter mice, rendered diabetic with streptozotocin and treated or not with carnosinol (FL-926-16), a selective scavenger of reactive carbonyl species (RCS) and, as such, an inhibitor of AGE formation. Mice were monitored for tumour development by in vivo bioluminescence imaging. At the end of the study, pancreatic tissue was collected for histology/immunohistochemistry and molecular analyses. Mechanistic studies were performed in pancreatic ductal adenocarcinoma cell lines challenged with high glucose, glycolysis- and glycoxidation-derived RCS, their protein adducts AGEs and sera from diabetic patients. Results: Cumulative incidence of invasive PaC at 22 weeks of age was 75% in untreated diabetic vs 25% in FL-926-16-gtreated diabetic and 8.3% in non-diabetic mice. FL-926-16 treatment suppressed systemic and pancreatic carbonyl stress, extracellular signal-regulated kinases (ERK) 1/2 activation, and nuclear translocation of Yes-associated protein (YAP) in pancreas. In vitro, RCS scavenging and AGE elimination completely inhibited cell proliferation stimulated by high glucose, and YAP proved essential in mediating the effects of both glucose-derived RCS and their protein adducts AGEs. However, RCS and AGEs induced YAP activity through distinct pathways, causing reduction of Large Tumour Suppressor Kinase 1 and activation of the Epidermal Growth Factor Receptor/ERK signalling pathway, respectively. Conclusions: An RCS scavenger and AGE inhibitor prevented the accelerating effect of diabetes on PainINs progression to invasive PaC, showing that hyperglycaemia promotes PaC mainly through increased carbonyl stress. In vitro experiments demonstrated that both circulating RCS/AGEs and tumour cell-derived carbonyl stress generated by excess glucose metabolism induce proliferation by YAP activation, hence providing a molecular mechanism underlying the link between diabetes and PaC (and cancer in general)

    Asynchronous Code-Division Random Access Using Convex Optimization

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    Many applications in cellular systems and sensor networks involve a random subset of a large number of users asynchronously reporting activity to a base station. This paper examines the problem of multiuser detection (MUD) in random access channels for such applications. Traditional orthogonal signaling ignores the random nature of user activity in this problem and limits the total number of users to be on the order of the number of signal space dimensions. Contention-based schemes, on the other hand, suffer from delays caused by colliding transmissions and the hidden node problem. In contrast, this paper presents a novel pairing of an asynchronous non-orthogonal code-division random access scheme with a convex optimization-based MUD algorithm that overcomes the issues associated with orthogonal signaling and contention-based methods. Two key distinguishing features of the proposed MUD algorithm are that it does not require knowledge of the delay or channel state information of every user and it has polynomial-time computational complexity. The main analytical contribution of this paper is the relationship between the performance of the proposed MUD algorithm in the presence of arbitrary or random delays and two simple metrics of the set of user codewords. The study of these metrics is then focused on two specific sets of codewords, random binary codewords and specially constructed algebraic codewords, for asynchronous random access. The ensuing analysis confirms that the proposed scheme together with either of these two codeword sets significantly outperforms the orthogonal signaling-based random access in terms of the total number of users in the system.Comment: Journal version of work presented at 2010 Allerton Conference on Communication, Control and Computing. Version 2 includes additional analysis of randomly distributed user delays as well as a comparison with a matched filter receive

    Evaluation of polyneuropathy markers in type 1 diabetic kidney transplant patients and effects of islet transplantation: Neurophysiological and skin biopsy longitudinal analysis

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    OBJECTIVE - The purpose of this study was to evaluate whether islet transplantation may stabilize polyneuropathy in uremic type 1 diabetic patients (end-stage renal disease [ESRD] and type 1 diabetes), who received a successful islet-after-kidney transplantation (KI-s). RESEARCH DESIGN AND METHODS - Eighteen KI-s patients underwent electroneurographic tests of sural, peroneal, ulnar, and median nerves: the nerve conduction velocity (NCV) index and amplitudes of both sensory action potentials (SAPs) and compound motor action potentials (CMAPs) were analyzed longitudinally at 2, 4, and 6 years after islet transplantation. Skin content of advanced glycation end products (AGEs) and expression of their specific receptors (RAGE) were also studied at the 4-year follow-up. Nine patients with ESRD and type 1 diabetes who received kidney transplantation alone (KD) served as control subjects. RESULTS - The NCV score improved in the KI-s group up to the 4-year time point (P = 0.01 versus baseline) and stabilized 2 years later, whereas the same parameter did not change significantly in the KD group throughout the follow-up period or when a cross-sectional analysis between groups was performed. Either SAP or CMAP amplitudes recovered in the KI-s group, whereas they continued worsening in KD control subjects. AGE and RAGE levels in perineurium and vasa nervorum of skin biopsies were lower in the KI-s than in the KD group (P < 0.01 for RAGE). CONCLUSIONS - Islet transplantation seems to prevent long-term worsening of polyneuropathy in patients with ESRD and type 1 diabetes who receive islets after kidney transplantation. No statistical differences between the two groups were evident on cross-sectional analysis. A reduction in AGE/RAGE expression in the peripheral nervous system was shown in patients receiving islet transplantation. © 2007 by the American Diabetes Association
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