Potentiometric Electronic Tongues for Foodstuff and Biosample Recognition—An Overview

Potentiometric sensors are attractive tools for the fabrication of various electronic tongues that can be used in wide area of applications, ranging from foodstuff recognition to environmental monitoring and medical diagnostics. Their main advantages are the ability to modify their selectivity (including cross-sensitivity effects) and the possibility of miniaturization using appropriate construction methods for the transducer part (e.g., with the use of solid-state technology). In this overview various examples of the design, performance, and applications of potentiometric electronic tongues are presented. The results summarize recent research in the field conducted in the Department of Microbioanalytics, Warsaw University of Technology (WUT)

Expected Policy Gradients

We propose expected policy gradients (EPG), which unify stochastic policy gradients (SPG) and deterministic policy gradients (DPG) for reinforcement learning. Inspired by expected sarsa, EPG integrates across the action when estimating the gradient, instead of relying only on the action in the sampled trajectory. We establish a new general policy gradient theorem, of which the stochastic and deterministic policy gradient theorems are special cases. We also prove that EPG reduces the variance of the gradient estimates without requiring deterministic policies and, for the Gaussian case, with no computational overhead. Finally, we show that it is optimal in a certain sense to explore with a Gaussian policy such that the covariance is proportional to the exponential of the scaled Hessian of the critic with respect to the actions. We present empirical results confirming that this new form of exploration substantially outperforms DPG with the Ornstein-Uhlenbeck heuristic in four challenging MuJoCo domains.Comment: Conference paper, AAAI-18, 12 pages including supplemen

Fourier Policy Gradients

We propose a new way of deriving policy gradient updates for reinforcement learning. Our technique, based on Fourier analysis, recasts integrals that arise with expected policy gradients as convolutions and turns them into multiplications. The obtained analytical solutions allow us to capture the low variance benefits of EPG in a broad range of settings. For the critic, we treat trigonometric and radial basis functions, two function families with the universal approximation property. The choice of policy can be almost arbitrary, including mixtures or hybrid continuous-discrete probability distributions. Moreover, we derive a general family of sample-based estimators for stochastic policy gradients, which unifies existing results on sample-based approximation. We believe that this technique has the potential to shape the next generation of policy gradient approaches, powered by analytical results

Renal ischemic postconditioning in a laparoscopic porcine model

Background: During procedures such as nephron sparing surgery, kidney transplantation and thorocoabdominal aorta aneurysm surgery the kidney is subjected to ischemia and reperfusion injury which may lead to loss of renal function. It has been proposed that an intermittent and brief repeated sequence of ischemia and reperfusion immediately after the main ischemic insult, known as ischemic postconditioning (IPoC) may protect the kidney from ischemic/reperfusion injury. The aim of the study was to evaluate an IPoC protocol in an in vivo porcine model of warm ischemic injury with 75 minutes occlusion of the left renal hilum followed by 48 hours reperfusion. Method: 16 hybrid pigs were randomised to either warm renal ischemia only (control) or warm renal ischemia followed by 6 x 15 seconds IPoC prior to laparoscopic surgery. Following anesthesia, the left kidney hilum was clamped for 75 minutes and the intervention group then received 6 x 15 seconds postconditioning. Serum creatinine and urea was measured following 24 hours and 48 hours respectively. Blood was analysed for neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1) and tumor necrosis factor alpha (TNFα). Just before 48 hours of reperfusion, urine was collected from each kidney separately for 60 minutes and sampled for analysis of NGAL. Urinary biomarker analysis of uNGAL and uKIM-1 was conducted between three groups: sham right kidney, IR left kidney, and IPoC left kidney. Results: Having only IR or IPoC significantly decreased corrected creatinine clearance (corCrCl) compared to not receiving an intervention (p<0.001). The IPoC group (n=4) had a higher corCrCl after 48 hours of reperfusion compared to the IR only group (n=3) (p= 0.04). There was a significant increase in uNGAL in IR group from PreOp to POD 2 (p=0.02). There was a significant effect of IR and IPoC on levels of uNGAL compared to sham right kidney (p=0.001). Having only IR or IPoC significantly increased uNGAL compared to receiving no IR (p=0.003). Conclusion: Preliminary results suggest that ischemic postconditioning attenuates warm ischemia/ reperfusion injury in a laparoscopic double kidney porcine model of warm ischemia

Rare species of field weeds of the south Podlasie Lowland and the neighbouring regions

Wydano przy pomocy finansowej Uniwersytetu Łódzkiego oraz Komitetu Badań NaukowychThe paper presents results of a study on the occurrence and localization of 30 field weed species in middle-eastern Poland. The species are considered to be regionally and overregionally rare and most of them grow on fertile soil (rendsine, alluvial soil). They include naturally rare species or species occurring on the border of geographical ranges (Anagallis arvensis var. azurea, Aphanes arvensis, Nigella arvensis) as well as species which are close to extinction (Bromus secatinus, Digitaria sanguinalis, Lolium remotum, Sherardia arvensis, Silene noctíflora). A group of important role are also expansive species talcing possession of habitats they have never grown in before (Asperugo procumhens, Falcaría vulgaris, Lathyrus tuberosus, Vicia grandiflora). Besides the list of localities (by provinces) general characteristics of distribution of each species and abundance and dynamic tolerance of localities are given.Zadanie pt. „Digitalizacja i udostępnienie w Cyfrowym Repozytorium Uniwersytetu Łódzkiego kolekcji czasopism naukowych wydawanych przez Uniwersytet Łódzki” nr 885/P-DUN/2014 zostało dofinansowane ze środków MNiSW w ramach działalności upowszechniającej naukę

Galanin modulates oxytocin release from rat hypothalamo-neurohypophysial explant in vitro &#8212; the role of acute or prolonged osmotic stimulus

Wstęp: Galanina (Gal) jako neuromodulator różnych procesów w ośrodkowym układzie nerwowym może być zaangażowana w regulacji funkcji części nerwowej przysadki. Celem obecnych doświadczeń było zbadanie wpływu Gal na uwalnianie oksytocyny (OT) in vitro: zastosowano ostry lub przewlekły bodziec osmotyczny jako czynnik pobudzający. Materiał i metody: Badania zostały przeprowadzone na 3-miesięcznych szczurach samcach, od których pobierano podwzgórze (Hth), część nerwową przysadki (NH) lub układ podwzgórzowo-przysadkowy (Hth-NH). Wpływ Gal na uwalnianie OT był badany w warunkach braku pobudzenia osmotycznego &#8212; stymulacja jonami K+ (seria 1), podczas ostrego pobudzenia osmotycznego wywołanego jonami Na+ zawartymi w płynie inkubacyjnym (seria 2) lub w trakcie stymulacji osmotycznej o charakterze pośrednim, kiedy tkanki nerwowe pobierano od zwierząt otrzymujących do picia 2% roztwór NaCl (stan przewodnienia hipertonicznego) (seria 3). Zawartość OT oznaczano metodą radioimmunologiczną. Wyniki: Seria 1: Galanina obecna w medium inkubacyjnym hamowała podstawowe uwalnianie OT z NH i układu Hth-NH, natomiast pobudzała podstawowe i stymulowane jonami K+ uwalnianie OT z Hth. Seria 2: Gal nie wywierała żadnego wpływu na sekrecję OT indukowaną jonami Na+ zawartymi w płynie inkubacyjnym. Seria 3: Gal była przyczyną wzrostu podstawowego uwalniania OT z NH oraz stymulowanego jonami potasu uwalniania OT z Hth oraz układu Hth-NH pobranych od szczurów w stanie przewodnienia hipertonicznego. Wnioski: Na podstawie obecnych badań in vitro można przyjąć, że: 1. Gal pełni funkcję neuromodulatora hamującego uwalnianie OT z części nerwowej przysadki, natomiast wywiera efekt przeciwny na poziomie podwzgórza. 2. Gal działa jako neuromodulator pobudzający uwalnianie OT w odpowiedzi na stan przewlekłego pobudzenia osmotycznego; ostry bodziec osmotyczny blokuje wrażliwość neuronów OT-ergicznych na działanie galaniny. (Endokrynol Pol 2013; 64 (2): 139&#8211;148)Introduction: Galanin (Gal) may be involved as the neuromodulator of different processes in the central nervous system in the regulation of neurohypophysial function. The aim of the present study was to examine the influence of Gal on oxytocin (OT) release in vitro: an acute or prolonged osmotic stimulus was used as the stimulatory agent. Material and methods: Experiments were carried out on three-month old male rats which acted as donors of isolated rat hypothalamus (Hth), neurohypophysis (NH) or hypothalamo-neurohypophysial explants (Hth-NH). The effect of Gal on OT secretion was studied under conditions of non-osmotic (i.e. K+-evoked) (series 1), direct osmotic (i.e. Na+-evoked) (series 2) or indirect osmotic stimulation (series 3; neural tissues were obtained from animals drinking 2% NaCl). OT content was determined by radioimmunoassay. Results: Galanin added into incubative media caused the inhibition of basal OT release from NH and Hth-NH explants prepared from euhydrated rats but stimulated basal and K+-stimulated OT release from the Hth tissue. Gal did not exert any influence on Na+-evoked OT secretion. We observed increased basal OT secretion from NH and K+-evoked respective OT release from Hth and Hth-NH explants taken from osmotically challenged rats under the influence of Gal. Conclusions: Present experiments in vitro show that: 1. Galanin plays the role of an inhibitory neuromodulator of OT release from the neurohypophysis; its effect is opposite at the hypothalamic level. 2. Galanin acts as the stimulatory neuromodulator of OT release in response to prolonged osmotic stimulus; an acute osmotic stimulus blocks OT-ergic neurons susceptible to Gal. (Endokrynol Pol 2013; 64 (2): 139&#8211;148