483 research outputs found
A proof of uniqueness of the Gurarii space
We present a short and elementary proof of isometric uniqueness of the
Gurarii space.Comment: 6 pages, some improvements incorporate
UTJECAJ DEPRESIJE NA PRITOK VODE U BUŠOTINE U KARBONATNIM PODINAMA KARPATSKOGA PREDGORJA NA JUGOISTOKU POLJSKE
This paper presents an analysis of well testing data, performed with a Drill stem test (DST). The carbonate levels of Mesozoic reservoir rocks were investigated in the research area of the Carpathian Foredeep. Based on the results of 17 two-cycle DST reservoir tests, the dependence of the volume of the reservoir water flow rate from the Mesozoic carbonate reservoirs (Upper Jurassic, Lower Cretaceous) to the wells as a function of the mean depression of bottom pressure was researched in the selected oil exploration area in the Carpathian Foredeep basement, SE Poland. Using methods of statistical analysis, a satisfactory correlation between variables for power and the exponential model was found, and a weak correlation for the linear model was found. A decrease in the value of the reservoir water flow rate along with an increase in pressure depression was found for the Mesozoic carbonate reservoirs, which may indicate the occurrence of fractures and micro-fractures shortening under extreme pressure depression and blockage phenomena of fractures and cavernous pores in the perimeter area by solid particles (cuttings, salt, polymers, etc.).U radu je prikazana analiza rezultata testiranja bušotina metodom DST-a (engl. skr. od Drill Stem Testing). Istraživanjem su obuhvaćene razine karbonata u stijenama mezozojskih ležišta u Karpatskome predgorju. Na temelju sedamnaest testova ispitivanja ležišta metodom DST-a, provođenih u dvama ciklusima, istražena je ovisnost volumena protoka vode iz mezozojskih karbonatnih ležišta (gornja jura i donja kreda) u bušotine, a kao funkcija prosječne depresije zbog tlaka na dnu bušotine. Kao objekti istraživanja odabrani su oni smješteni upravo u naftnoj zoni Karpatskoga predgorja, na jugoistoku Poljske. Na temelju statističke analize uočena je zadovoljavajuća korelacija između varijabli potencijskoga i eksponencijalnoga modela te slaba korelacija kod linearnoga modela. Smanjenje pritoka ležišne vode iz mezozojskih karbonatnih ležišta, uz povećanje depresije, potencijalno upućuje na pojavu smanjivanja pukotina i mikropukotina uslijed prevelike depresije te na začepljivanje fraktura i šupljina nastalih otapanjem, do čega dolazi zbog krutih čestica poput krhotina, soli, polimera itd
History and current research in the field of radiochemistry at Maria Curie-Skłodowska University
Activated Notch2 Signaling Inhibits Differentiation of Cerebellar Granule Neuron Precursors by Maintaining Proliferation
AbstractIn the developing cerebellar cortex, granule neuron precursors (GNPs) proliferate and commence differentiation in a superficial zone, the external granule layer (EGL). The molecular basis of the transition from proliferating precursors to immature differentiating neurons remains unknown. Notch signaling is an evolutionarily conserved pathway regulating the differentiation of precursor cells of many lineages. Notch2 is specifically expressed in proliferating GNPs in the EGL. Treatment of GNPs with soluble Notch ligand Jagged1, or overexpression of activated Notch2 or its downstream target HES1, maintains precursor proliferation. The addition of GNP mitogens Jagged1 or Sonic Hedgehog (Shh) upregulates the expression of HES1, suggesting a role for HES1 in maintaining precursor proliferation
Anatomic variability of groin innervation
Inguinal hernia repairs are very common yet fairly complex surgical procedures.Variations in the anatomical course of the inguinal nerves require that diligenceis taken in their proper recognition. Inadvertent surgical injury to these nerves isassociated with long term postoperative pain and complications. The aim of thepresent study was to highlight the complexity and variation in the innervation ofthe inguinal region in order to increase proper nerve identification during surgicalinterventions. Bilateral dissection of the inguinal and posterior abdominal regionsin one human male cadaver revealed an atypical anatomic topography of thegroin innervation. This unusual case was observed at the Jagiellonian UniversityAnatomy Department during routine cadaveric preparations. The left ilioinguinalnerve was absent. The left genital branch of the genitofemoral nerve arose higherthan expected from the lumbar plexus and supplied the groin region, which istypically innervated by the ilioinguinal nerve. Furthermore, the left lateral cutaneousfemoral nerve and the right genital branch of the genitofemoral nerve alsofollowed uncharacteristic courses. Awareness of topographical nerve variationsduring inguinal hernia repair will help surgeons identify and preserve importantnerves, thus decreasing the incidence of chronic postoperative pain
Differential role of ventral tegmental area acetylcholine and N-methyl-D-aspartate receptors in cocaine-seeking
Exposure to drug-associated cues evokes drug-seeking behavior and is regarded as a major cause of relapse. Cues evoke burst firing of ventral tegmental area (VTA) dopamine (DA) neurons and phasic DA release in the nucleus accumbens (NAc). Cholinergic and glutamatergic input to the VTA is suggested to gate phasic DA activity. However, the role of VTA cholinergic and glutamatergic receptors in regulating phasic dopamine release and cue-induced drug-seeking in cocaine experienced subjects is not known. In male Sprague-Dawley rats, we found that VTA inactivation strongly inhibited, while VTA stimulation promoted, cocaine-seeking behavior during early withdrawal. Blockade of phasic activated D1 receptors in the NAc core also strongly inhibited cue-induced cocaine-seeking--suggesting an important role of phasic DA activity in the VTA to NAc core circuit. Next, we examined the role of VTA acetylcholine receptors (AChRs) and N-methyl-D-aspartate receptors (NMDARs) in regulating both NAc core phasic DA release and cue-induced cocaine-seeking. In cocaine naïve subjects, VTA infusion of the nicotinic acetylcholine receptor (AChR) antagonist mecamylamine, the muscarinic AChR antagonist scopolamine, or the NMDAR antagonist AP-5, led to robust attenuation of phasic DA release in the NAc core. During early cocaine withdrawal, VTA infusion of AP-5 had limited effects on NAc phasic DA release and cue-induced cocaine-seeking while VTA infusion of mecamylamine or scopolamine robustly inhibited both phasic DA release and cocaine-seeking. The results demonstrate that VTA AChRs, but not NMDARs, strongly regulate cue-induced cocaine-seeking and phasic DA release during early cocaine withdrawal
Deliverable 9.1 - Report on mixtures and implementation strategy in Europe – Assessment of chemical mixtures under consideration of current and future regulatory requirements and scientific approaches
This report gives an overview on the regulatory processes and requirements for risk assessment of chemical mixtures, identifies gaps in the European legislation and summarises potential approaches for the health risk assessment of chemical mixtures
Advances in studying phasic dopamine signaling in brain reward mechanisms
The last sixty years of research has provided extraordinary advances of our knowledge of the reward system. Since its discovery as a neurotransmitter by Carlsson and colleagues (1), dopamine (DA) has emerged as an important mediator of reward processing. As a result, a number of electrochemical techniques have been developed to measure DA in the brain. Together, these techniques have begun to elucidate the complex roles of tonic and phasic DA signaling in reward processing and addiction. In this review, we will first provide a guide for the most commonly used electrochemical methods for DA detection and describe their utility in furthering our knowledge about DA's role in reward and addiction. Second, we will review the value of common in vitro and in vivo preparations and describe their ability to address different types of questions. Last, we will review recent data that has provided new mechanistic insight of in vivo phasic DA signaling and its role in reward processing and reward-mediated behavior
Myosin II Motors and F-Actin Dynamics Drive the Coordinated Movement of the Centrosome and Soma during CNS Glial-Guided Neuronal Migration
SummaryLamination of cortical regions of the vertebrate brain depends on glial-guided neuronal migration. The conserved polarity protein Par6α localizes to the centrosome and coordinates forward movement of the centrosome and soma in migrating neurons. The cytoskeletal components that produce this unique form of cell polarity and their relationship to polarity signaling cascades are unknown. We show that F-actin and Myosin II motors are enriched in the neuronal leading process and that Myosin II activity is necessary for leading process actin dynamics. Inhibition of Myosin II decreased the speed of centrosome and somal movement, whereas Myosin II activation increased coordinated movement. Ectopic expression or silencing of Par6α inhibited Myosin II motors by decreasing Myosin light-chain phosphorylation. These findings suggest leading-process Myosin II may function to “pull” the centrosome and soma forward during glial-guided migration by a mechanism involving the conserved polarity protein Par6α
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