149 research outputs found
A Real-Time Capable Software-Defined Receiver Using GPU for Adaptive Anti-Jam GPS Sensors
Due to their weak received signal power, Global Positioning System (GPS) signals are vulnerable to radio frequency interference. Adaptive beam and null steering of the gain pattern of a GPS antenna array can significantly increase the resistance of GPS sensors to signal interference and jamming. Since adaptive array processing requires intensive computational power, beamsteering GPS receivers were usually implemented using hardware such as field-programmable gate arrays (FPGAs). However, a software implementation using general-purpose processors is much more desirable because of its flexibility and cost effectiveness. This paper presents a GPS software-defined radio (SDR) with adaptive beamsteering capability for anti-jam applications. The GPS SDR design is based on an optimized desktop parallel processing architecture using a quad-core Central Processing Unit (CPU) coupled with a new generation Graphics Processing Unit (GPU) having massively parallel processors. This GPS SDR demonstrates sufficient computational capability to support a four-element antenna array and future GPS L5 signal processing in real time. After providing the details of our design and optimization schemes for future GPU-based GPS SDR developments, the jamming resistance of our GPS SDR under synthetic wideband jamming is presented. Since the GPS SDR uses commercial-off-the-shelf hardware and processors, it can be easily adopted in civil GPS applications requiring anti-jam capabilities
UNSW GNSS interference detection device
The radio frequency signals transmitted by Global Navigation Satellite
Systems (GNSS) have very low power and are susceptible to radio frequency
interference. Most GNSS receivers do not measure and quantify any
interference they may be suffering; they just do what they can with the
signals they receive. Interference can lead to poor receiver positioning
performance and, if severe, such as in a jamming environment, complete
positioning failure. Interference monitoring could be beneficial in areas such
as airports where GNSS positioning will soon be more critical and
interference could be present.
This paper outlines the work to date on developing an interference detection
device based around the Namuru GNSS receiver platform developed at the
University of New South Wales (UNSW). The detection device is a
hardware and embedded software realization of detection schemes and
algorithms developed at UNSW. The detection technique is briefly explained
followed by a discussion of the hardware design, software implementation,
testing and results, some conclusions and finally, a discussion of possible
future activities
Sealing efficacy of mineral trioxide aggregate with and without nanosilver for root end filling: an in vitro bacterial leakage study
Various materials have been added to mineral trioxide aggregate to enhance its properties. This study was aimed to compare the sealing efficacy of MTA with and without nanosilver using bacterial leakage approach.
Seventy canine teeth were prepared and obturated. Then, after apical resection, the root-end cavities were prepared by ultrasonic retrotips. Teeth were randomly divided into 4 groups containing two experimental groups (n=30) and two negative and positive controls (n=5). In group 1 and 2, root-end cavities were respectively filled with MTA and MTA with nanosilver (by 1% weight). Leakage assessment was carried out by bacterial leakage apparatus with Enterococcus faecalis species. Leakage comparison between experimental groups was done using Mann-Whitney test by Spss 16 software at significancy level of 0.05.
The median bacterial leakages for MTA and MTA with nanosilver were 19 and 2, respectively. The mean bacterial leakages for MTA and MTA with nanosilver were 30.06±28.67 and 9.66±14.25, respectively. Mann-Whitney test indicated that there was a significant difference in bacterial leakage day between two experimental groups (P=0.002).
Based on the findings of this in-vitro bacterial leakage study, adding nanosilver to MTA decreased its sealing ability
Tropisetron attenuated the anxiogenic effects of social isolation by modulating nitrergic system and mitochondrial function.
Abstract
BACKGROUND:
Early social isolation stress (SIS) is associated with the occurrence of anxiety behaviors. It seems interaction between the nitrergic system and mitochondrial function plays a role in mediating the anxiety-like behaviors. In this study, we aimed to investigate the anxiolytic effects of tropisetron in animal model of SIS and we try to illustrate the possible role of nitrergic system and mitochondrial function.
METHODS:
We applied early social isolation paradigm to male NMRI mice. Animals treated with various doses of tropisetron, nitric oxide agents or their combination and anxiety-like behaviors of animals were assessed using valid behavioral tests including elevated plus maze (EPM), open-field test (OFT) and hole-board test (HBT) in their adulthood. Effects of housing conditions and drug treatments on the mitochondrial function were investigated in the hippocampus by assessing the ATP, GSH, ROS and nitrite levels.
RESULTS:
Anxiogenic effects of early SIS were assessed in the EPM, OFT, and HBT. Also, SIS disrupted mitochondrial function and caused oxidative stress in the hippocampus of stressed animals. Tropisetron showed an anxiolytic effect in the stressed mice. Also, these effects were mediated by nitrergic system by affecting mitochondrial function and modulating the oxidative stress. L-arginine, a nitric oxide precursor, abolished the anxiolytic effects of tropisetron in the behavioral tasks and blocked the protective effects of it against mitochondrial and oxidative challenge.
CONCLUSIONS AND GENERAL SIGNIFICANCE:
Our results demonstrated tropisetron attenuated the anxiogenic effects of SIS by mitigation of the negative effects of nitric oxide on mitochondrial functio
Anxiety- and Depressive-Like Behaviors are Associated with Altered Hippocampal Energy and Inflammatory Status in a Mouse Model of Crohn’s Disease
Abstract—Depression and anxiety are common comorbid disorders observed in patients with inflammatory bowel
disease (IBD). Increasing line of evidence indicates that immune-inflammatory responses are involved in cooccurrence
of mood disorders and IBD. However, the mechanisms through which immune-inflammatory pathways
modulate this comorbidity are not yet understood. This study investigated the role of innate immunity in
the development of behavioral abnormalities associated with an animal model of Crohn’s disease (CD). To do this,
we induced colitis in male adult mice by intrarectal (i.r.) injection of DNBS (Dinitrobenzene sulfonic acid). After 3
days, we performed behavioral tests for anxiety- and depressive-like behaviors as well as tissue collection. Our
results showed that DNBS-induced colonic inflammatory responses were accompanied by infiltration of inflammatory
cells, and increased expression of genes involved in toll-like receptor signaling pathway in intestinal tissue.
Furthermore, the DNBS-treated mice showed depressive- and anxiety-like behaviors which were associated
with increased expression of the inflammatory genes and abnormal mitochondrial function in the hippocampus.
These results suggest that peripheral inflammation is able to increase the transcriptional level of the genes in tolllike
receptor pathway, induces abnormal mitochondrial function in the hippocampus, and these negative effects
may be involved in the co-occurrence of anxiety and depression in early stages of CD. � 2017 IBRO. Published by
Elsevier Ltd. All rights reserved
Loss of prostatic acid phosphatase and α-synuclein cause motor circuit degeneration without altering cerebellar patterning
Prostatic acid phosphatase (PAP), which is secreted by prostate, increases in some diseases such as prostate cancer. PAP is also present in the central nervous system. In this study we reveal that α-synuclein (Snca) gene is co-deleted/mutated in PAP null mouse. It is indicated that mice deficient in transmembrane PAP display neurological alterations. By using immunohistochemistry, cerebellar cortical neurons and zone and stripes pattern were studied in Pap-/- ;Snca-/- mouse cerebellum. We show that the Pap-/- ;Snca-/- cerebellar cortex development appears to be normal. Compartmentation genes expression such as zebrin II, HSP25, and P75NTR show the zone and stripe phenotype characteristic of the normal cerebellum. These data indicate that although aggregation of PAP and SNCA causes severe neurodegenerative diseases, PAP -/- with absence of the Snca does not appear to interrupt the cerebellar architecture development and zone and stripe pattern formation. These findings question the physiological and pathological role of SNCA and PAP during cerebellar development or suggest existence of the possible compensatory mechanisms in the absence of these genes.Peer reviewe
Lithium attenuated the depressant and anxiogenic effect of juvenile social stress through mitigating the negative impact of interlukin-1β and nitric oxide on hypothala...
Abstract—The neuroimmune-endocrine dysfunction has
been accepted as one of fundamental mechanisms contributing
to the pathophysiology of psychiatric disorders
including depression and anxiety. In this study, we aimed
to evaluate the involvement of hypothalamic–pituitary–adre
nal (HPA) axis, interleukin-1b, and nitrergic system in mediating
the negative behavioral impacts of juvenile social isolation
stress (SIS) in male mice. We also investigated the
possible protective effects of lithium on behavioral and neurochemical
changes in socially isolated animals. Results
showed that experiencing 4-weeks of juvenile SIS provoked
depressive and anxiety-like behaviors that were associated
with hyper responsiveness of HPA axis, upregulation of
interleukin-1b, and nitric oxide (NO) overproduction in the
pre-frontal cortex and hippocampus. Administration of
lithium (10 mg/kg) significantly attenuated the depressant
and anxiogenic effects of SIS in behavioral tests. Lithium
also restored the negative effects of SIS on cortical and hippocampal
interleukin-1b and NO as well as HPA axis deregulation.
Unlike the neutralizing effects of L-arginine (NO
precursor), administration of L-NAME (3 mg/kg) and
aminoguanidine (20 mg/kg) potentiated the positive effects
of lithium on the behavioral and neurochemical profile of
isolated mice. In conclusion, our results revealed that juvenile
SIS-induced behavioral deficits are associated with
abnormalities in HPA-immune function. Also, we suggest
that alleviating effects of lithium on behavioral profile
of isolated mice may be partly mediated by mitigating
the negative impact of NO on HPA-immune function.
� 2015 IBRO. Published by Elsevier Ltd. All rights reserve
Morphine modulates the effects of histamine H1 and H3 receptors on seizure susceptibility in pentylenetetrazole-induced seizure model of mice
Histamine regulates release of neurotransmitters such as dopamine, serotonin, gamma-aminobutyric
acid (GABA), glutamate and also is involved in several functions in central nervous system (CNS). It has
been shown that histamine participates in disorders like seizure. It has been well documented that
morphine dose-dependently induces anti or proconvulsant effects. In the current study, we firstly
showed that morphine (1 mg/kg) exerts anticonvulsant effects which significantly reversed by naltrexone
administration. Secondly, we determined seizure threshold for H1 and H3 receptors agonists and
antagonists in mouse model of pentylenetetrazole (PTZ)-induced clonic seizures. Our results showed that
activation of H1 receptors by 2-(2-Pyridyl)-ethylamine exerts anticonvulsant properties while inhibition
of H1 receptors by pyrilamine maleate induced proconvulsant effects. Furthermore, we showed that
immepip dihydrobromide, a H3 receptor agonist, increased seizure susceptibility to PTZ whereas thioperamide,
a H3 receptor antagonist increased seizure threshold. We also revealed that pretreatment with
morphine potently reversed the effects of histaminergic system on seizure threshold suggesting the
involvement of opioid system in alteration of seizure threshold by histaminergic drug
NMDA RECEPTORS ARE INVOLVED IN THE ANTIDEPRESSANT-LIKE EFFECTS OF CAPSAICIN FOLLOWING AMPHETAMINE WITHDRAWAL IN MALE MICE
Abstract—Amphetamine withdrawal (AW) is accompanied
by diminished pleasure and depression which plays a key
role in drug relapse and addictive behaviors. There is no effi-
cient treatment for AW-induced depression and underpinning
mechanisms were not well determined. Considering
both transient receptor potential cation channel, subfamily
V, member 1 (TRPV1) and N-Methyl-D-aspartate (NMDA)
receptors contribute to pathophysiology of mood and addictive
disorders, in this study, we investigated the role of
TRPV1 and NMDA receptors in mediating depressive-like
behaviors following AW in male mice. Results revealed that
administration of capsaicin, TRPV1 agonist, (100 lg/mouse,
i.c.v.) and MK-801, NMDA receptor antagonist (0.005 mg/kg,
i.p.) reversed AW-induced depressive-like behaviors in
forced swimming test (FST) and splash test with no effect
on animals’ locomotion. Co-administration of sub-effective
doses of MK-801 (0.001 mg/kg, i.p.) and capsaicin
(10 lg/mouse, i.c.v) exerted antidepressant-like effects in
behavioral tests. Capsazepine, TRPV1 antagonist,
(100 lg/mouse, i.c.v) and NMDA, NMDA receptor agonist
(7.5 mg/kg, i.p.) abolished the effects of capsaicin and MK801,
respectively. None of aforementioned treatments had
any effect on behavior of control animals. Collectively, our
findings showed that activation of TRPV1 and blockade of
NMDA receptors produced antidepressant-like effects in
male mice following AW, and these receptors are involved
in AW-induced depressive-like behaviors. Further, we found
that rapid antidepressant-like effects of capsaicin in FST and
splash test are partly mediated by NMDA receptors. � 2016
Published by Elsevier Ltd on behalf of IBRO
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