150 research outputs found

    Internal Flow Physics of a Fluidic Oscillator in the Transition Regime

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    An experimental investigation of the underlying flow physics of a dual jet interaction fluidic oscillator has been conducted in the transition regime for a Reynolds number of 1680. The transition regime is defined as a narrow range of flow rates between two other operating modes of the fluidic oscillator. Particle image velocimetry (PIV) was used with refractive index matching sodium iodide solution to minimize reflections from the actuator geometry and obtain detailed internal velocity fields. PIV results showed that the inter-action of the two internal jets and the resultant vortices are responsible for the oscillation mechanism in the transition regime. Two side vortices sustain their existence throughout the oscillation period by altering their size, shape and strength, and a dome vortex is created twice each oscillation period (once from each jet). The dome vortex plays a key role in the kinetic energy transfer mechanism inside the oscillator by means of jet bifurcations. The primary oscillation mechanism in the transition regime is that each internal jet’s connection with the exiting jet is cut completely by the dome vortex in every period. This is in contrast to the low flow rate oscillation mechanism in which the oscillations are created by continuous collisions of the jets. Furthermore, the internal jets were observed to energize the side vortex on the opposite side of the chamber – a phenomenon which was not observed in the low flow rate regimeDFG, 200291049, SFB 1029: TurbIn - Signifikante Wirkungsgradsteigerung durch gezielte, interagierende Verbrennungs- und Strömungsinstationaritäten in Gasturbine

    Effect of Geometry Modifications on the Vectoring Performance of a Controlled Jet

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    Jet vectoring performances of ten different designs with various depths and geometrical outlines were quantified through constant temperature anemometry measurements for a Reynolds number range from 10,000 to 30,000 by using passive and active flow control methods at cold flow. The reference design was based on NASA’s double throat nozzle concept and a self-injection double throat nozzle design that uses similar flow control concept as the reference design, were also tested for performance comparison. Furthermore, jet vectoring performance of a single throat design, utilizing Coanda effect for jet vectoring, was also quantified. Results indicated jet vectoring angles starting from 2° up to 47° for a control jet flow rate range from 1% up to 10% with respect to the primary jet flow rate in the investigated Re range. Maximum jet vectoring angle was achieved with a single throat design which incorporates small step geometry before the Coanda surface for more effective flow attachment and these results were compared with the vectoring performance of the double throat nozzle designs

    Research on the effectiveness and tolerability of vaginal administration of probiotic Lactobacillus acidophilus in women with symptoms of colpitis

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    Probiotici su živi mikroorganizmi koji primijenjeni u dostatnoj količini mijenjaju sastav i metaboličku aktivnost mikroflore ili utječu na imunološki sustav što djeluje povoljno na zdravlje čovjeka. Lactobacillus acidophilus je najbolje proučena acidofilna bakterija koju prirodno nalazimo u jogurtu i acidofilnom mlijeku. Cilj ovog ispitivanja je bio istražiti djelotvornost i podnošljivost vaginalne primjene probiotika Lactobacillus acidophilus u bolesnica sa simptomima kolpitisa. U ovom prospektivnom ispitivanju djelotvornosti i podnošljivosti sedmodnevne primjene Lactobacillus acidophilus solucije za vaginalnu primjenu u žena s kolpitisom – probiotik Lactobacillus acidophilus se pokazao djelotvoran s obzirom da je 42 od ukupno 50 liječenih žena bilo klinički izliječeno. Klinički uspjeh bio je češći u žena iznad 50 godina starosti, te u žena koje su imale simptome iritacije i svrbeža. Lactobacillus acidophilus solucija za vaginalnu primjenu se pokazala izrazito podnošljiva s obzirom da niti jedna od 50 liječenih žena nije imala nuspojave liječenja.Probiotics are live microorganisms which, when administered in adequate amounts, change the structure and metabolic activity of human microflora or affect the immune system in a way beneficial for human health. Lactobacillus acidophilus is the most studied acidophilus bacteria that is naturally found in yogurt and acidophilus milk. The aim of this research was to investigate the effectiveness and tolerability of vaginal administration of probiotic Lactobacillus acidophilus in patients with symptoms of colpitis. In this prospective research on the efficacy and tolerability of Lactobacillus acidophilus vaginal solution used for 7 days in women with colpitis – probiotic Lactobacillus acidophilus has proved effective in 42 out of 50 treated women. Clinical success was more common in women over 50 years of age and in women with symptoms of irritation and pruritis. Lactobacillus acidophilus vaginal solution has proved especially tolerable since not one among 50 treated women experienced treatmant side effects

    The Child and Adolescent Psychiatry: Study of Training in Europe (CAP-STATE)

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    There is great cultural diversity across Europe. This is reflected in the organisation of child and adolescent mental health (CAMH) services and the training of the respective professionals in different countries in Europe. Patients and their parents will want a high quality, knowledgeable, and skillful service from child and adolescent psychiatrists (CAPs) wherever they see them in Europe. A European comparison of training programs allows all stakeholders in different European countries to assess the diversity and to initiate discussions as to the introduction of improvements within national training programs. Major issues to be addressed in comparing child and adolescent psychiatric training programs across Europe include: (1) formal organisation and content of training programs and the relationship to adult psychiatry and paediatrics; (2) flexibility of training, given different trainee interests and that many trainees will have young families; (3) quality of governance of training systems; (4) access to research; and (5) networking. The Child and Adolescent Psychiatry-Study of Training in Europe (CAP-State) is a survey of training for child and adolescent psychiatrists (CAPs) across European countries. It aims to revisit and extend the survey carried out in 2006 by Karabekiroglu and colleagues. The current article is embedded in a special issue of European Child + Adolescent Psychiatry attempting to for the first time address training in CAP at the European and global levels. Structured information was sought from each of 38 European and neighboring countries (subsequently loosely referred to as Europe) and obtained from 31. The information was provided by a senior trainee or recently qualified specialist and their information was checked and supplemented by information from a senior child and adolescent psychiatry trainer. Results showed that there is a very wide range of provision of training in child and adolescent psychiatry in different countries in Europe. There remains very substantial diversity in training across Europe and in the degree to which it is subject to national oversight and governance. Some possible reasons for this variation are discussed and some recommendations made.info:eu-repo/semantics/publishedVersio

    NMDA Receptors on Non-Dopaminergic Neurons in the VTA Support Cocaine Sensitization

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    The initiation of behavioral sensitization to cocaine and other psychomotor stimulants is thought to reflect N-methyl-D-aspartate receptor (NMDAR)-mediated synaptic plasticity in the mesolimbic dopamine (DA) circuitry. The importance of drug induced NMDAR mediated adaptations in ventral tegmental area (VTA) DA neurons, and its association with drug seeking behaviors, has recently been evaluated in Cre-loxp mice lacking functional NMDARs in DA neurons expressing Cre recombinase under the control of the endogenous dopamine transporter gene (NR1(DATCre) mice).Using an additional NR1(DATCre) mouse transgenic model, we demonstrate that while the selective inactivation of NMDARs in DA neurons eliminates the induction of molecular changes leading to synaptic strengthening, behavioral measures such as cocaine induced locomotor sensitization and conditioned place preference remain intact in NR1(DATCre) mice. Since VTA DA neurons projecting to the prefrontal cortex and amygdala express little or no detectable levels of the dopamine transporter, it has been speculated that NMDA receptors in DA neurons projecting to these brain areas may have been spared in NR1(DATCre) mice. Here we demonstrate that the NMDA receptor gene is ablated in the majority of VTA DA neurons, including those exhibiting undetectable DAT expression levels in our NR1(DATCre) transgenic model, and that application of an NMDAR antagonist within the VTA of NR1(DATCre) animals still blocks sensitization to cocaine.These results eliminate the possibility of NMDAR mediated neuroplasticity in the different DA neuronal subpopulations in our NR1(DATCre) mouse model and therefore suggest that NMDARs on non-DA neurons within the VTA must play a major role in cocaine-related addictive behavior

    Mutation and deletion analysis of GFRα-1, encoding the co-receptor for the GDNF/RET complex, in human brain tumours

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    Glial cell line-derived neurotrophic factor (GDNF) plays a key role in the control of vertebrate neuron survival and differentiation in both the central and peripheral nervous systems. GDNF preferentially binds to GFRα-1 which then interacts with the receptor tyrosine kinase RET. We investigated a panel of 36 independent cases of mainly advanced sporadic brain tumours for the presence of mutations in GDNF and GFRα-1. No mutations were found in the coding region of GDNF. We identified six previously described GFRα-1 polymorphisms, two of which lead to an amino acid change. In 15 of 36 brain tumours, all polymorphic variants appeared to be homozygous. Of these 15 tumours, one also had a rare, apparently homozygous, sequence variant at codon 361. Because of the rarity of the combination of homozygous sequence variants, analysis for hemizygous deletion was pursued in the 15 samples and loss of heterozygosity was found in 11 tumours. Our data suggest that intragenic point mutations of GDNF or GFRα-1 are not a common aetiologic event in brain tumours. However, either deletion of GFRα-1 and/or nearby genes may contribute to the pathogenesis of these tumours

    Selective Deletion of PTEN in Dopamine Neurons Leads to Trophic Effects and Adaptation of Striatal Medium Spiny Projecting Neurons

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    The widespread distribution of the tumor suppressor PTEN in the nervous system suggests a role in a broad range of brain functions. PTEN negatively regulates the signaling pathways initiated by protein kinase B (Akt) thereby regulating signals for growth, proliferation and cell survival. Pten deletion in the mouse brain has revealed its role in controlling cell size and number. In this study, we used Cre-loxP technology to specifically inactivate Pten in dopamine (DA) neurons (Pten KO mice). The resulting mutant mice showed neuronal hypertrophy, and an increased number of dopaminergic neurons and fibers in the ventral mesencephalon. Interestingly, quantitative microdialysis studies in Pten KO mice revealed no alterations in basal DA extracellular levels or evoked DA release in the dorsal striatum, despite a significant increase in total DA tissue levels. Striatal dopamine receptor D1 (DRD1) and prodynorphin (PDyn) mRNA levels were significantly elevated in KO animals, suggesting an enhancement in neuronal activity associated with the striatonigral projection pathway, while dopamine receptor D2 (DRD2) and preproenkephalin (PPE) mRNA levels remained unchanged. In addition, PTEN inactivation protected DA neurons and significantly enhanced DA-dependent behavioral functions in KO mice after a progressive 6OHDA lesion. These results provide further evidence about the role of PTEN in the brain and suggest that manipulation of the PTEN/Akt signaling pathway during development may alter the basal state of dopaminergic neurotransmission and could provide a therapeutic strategy for the treatment of Parkinson's disease, and other neurodegenerative disorders

    Real-Space Mesh Techniques in Density Functional Theory

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    This review discusses progress in efficient solvers which have as their foundation a representation in real space, either through finite-difference or finite-element formulations. The relationship of real-space approaches to linear-scaling electrostatics and electronic structure methods is first discussed. Then the basic aspects of real-space representations are presented. Multigrid techniques for solving the discretized problems are covered; these numerical schemes allow for highly efficient solution of the grid-based equations. Applications to problems in electrostatics are discussed, in particular numerical solutions of Poisson and Poisson-Boltzmann equations. Next, methods for solving self-consistent eigenvalue problems in real space are presented; these techniques have been extensively applied to solutions of the Hartree-Fock and Kohn-Sham equations of electronic structure, and to eigenvalue problems arising in semiconductor and polymer physics. Finally, real-space methods have found recent application in computations of optical response and excited states in time-dependent density functional theory, and these computational developments are summarized. Multiscale solvers are competitive with the most efficient available plane-wave techniques in terms of the number of self-consistency steps required to reach the ground state, and they require less work in each self-consistency update on a uniform grid. Besides excellent efficiencies, the decided advantages of the real-space multiscale approach are 1) the near-locality of each function update, 2) the ability to handle global eigenfunction constraints and potential updates on coarse levels, and 3) the ability to incorporate adaptive local mesh refinements without loss of optimal multigrid efficiencies.Comment: 70 pages, 11 figures. To be published in Reviews of Modern Physic

    Methamphetamine Preconditioning Alters Midbrain Transcriptional Responses to Methamphetamine-Induced Injury in the Rat Striatum

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    Methamphetamine (METH) is an illicit drug which is neurotoxic to the mammalian brain. Numerous studies have revealed significant decreases in dopamine and serotonin levels in the brains of animals exposed to moderate-to-large METH doses given within short intervals of time. In contrast, repeated injections of small nontoxic doses of the drug followed by a challenge with toxic METH doses afford significant protection against monoamine depletion. The present study was undertaken to test the possibility that repeated injections of the drug might be accompanied by transcriptional changes involved in rendering the nigrostriatal dopaminergic system refractory to METH toxicity. Our results confirm that METH preconditioning can provide significant protection against METH-induced striatal dopamine depletion. In addition, the presence and absence of METH preconditioning were associated with substantial differences in the identity of the genes whose expression was affected by a toxic METH challenge. Quantitative PCR confirmed METH-induced changes in genes of interest and identified additional genes that were differentially impacted by the toxic METH challenge in the presence of METH preconditioning. These genes include small heat shock 27 kD 27 protein 2 (HspB2), thyrotropin-releasing hormone (TRH), brain derived neurotrophic factor (BDNF), c-fos, and some encoding antioxidant proteins including CuZn superoxide dismutase (CuZnSOD), glutathione peroxidase (GPx)-1, and heme oxygenase-1 (Hmox-1). These observations are consistent, in part, with the transcriptional alterations reported in models of lethal ischemic injuries which are preceded by ischemic or pharmacological preconditioning. Our findings suggest that multiple molecular pathways might work in tandem to protect the nigrostriatal dopaminergic pathway against the deleterious effects of the toxic psychostimulant. Further analysis of the molecular and cellular pathways regulated by these genes should help to provide some insight into the neuroadaptive potentials of the brain when repeatedly exposed to drugs of abuse
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