Abstract: The combination of the properties of graphene oxide
(OG) and PVDF homopolymer makes their combined composite
materials as multifunctional systems with great potential. Knowledge
of the molecular structure is essential for better use. In this work, the
degradation of PVDF polymer exposed to gamma irradiation in
oxygen atmosphere in high dose rate has been studied and compared
to degradation of PVDF/OG composites. The samples were irradiated
with a Co-60 source at constant dose rate, with doses ranging from
100 kGy to 1,000 kGy. In FTIR data shown that the formation of
oxidation products was at the both samples with formation of
carbonyl and hydroxyl groups amongst the most prevalent products
in the pure PVDF samples. In the other hand, the composites samples
exhibit less presence of degradation products with predominant
formation of carbonyl groups, these results also seen in the UV-Vis
analysis. The results show that the samples of composites may have
greater resistance to the irradiation process, since they have less
degradation products than pure PVDF samples seen by spectroscopic
techniques.
Abstract: The irradiation of polymeric materials has received
much attention because it can produce diverse changes in chemical
structure and physical properties. Thus, studying the chemical and
structural changes of polymers is important in practice to achieve
optimal conditions for the modification of polymers. The effect of
gamma irradiation on the crystalline structure of poly(vinylidene
fluoride) (PVDF) has been investigated using differential scanning
calorimetry (DSC) and X-ray diffraction techniques (XRD). Gamma
irradiation was carried out in atmosphere air with doses between 100
kGy at 3,000 kGy with a Co-60 source. In the melting thermogram of
the samples irradiated can be seen a bimodal melting endotherm is
detected with two melting temperature. The lower melting
temperature is attributed to melting of crystals originally present and
the higher melting peak due to melting of crystals reorganized upon
heat treatment. These results are consistent with those obtained by
XRD technique showing increasing crystallinity with increasing
irradiation dose, although the melting latent heat is decreasing.
Abstract: Fading noise degrades the performance of cellular
communication, most notably in femto- and pico-cells in 3G and 4G
systems. When the wireless channel consists of a small number of
scattering paths, the statistics of fading noise is not analytically
tractable and poses a serious challenge to developing closed
canonical forms that can be analysed and used in the design of
efficient and optimal receivers. In this context, noise is multiplicative
and is referred to as stochastically local fading. In many analytical
investigation of multiplicative noise, the exponential or Gamma
statistics are invoked. More recent advances by the author of this
paper utilized a Poisson modulated-weighted generalized Laguerre
polynomials with controlling parameters and uncorrelated noise
assumptions. In this paper, we investigate the statistics of multidiversity
stochastically local area fading channel when the channel
consists of randomly distributed Rayleigh and Rician scattering
centers with a coherent Nakagami-distributed line of sight component
and an underlying doubly stochastic Poisson process driven by a
lognormal intensity. These combined statistics form a unifying triply
stochastic filtered marked Poisson point process model.
Abstract: Abstract—[Tris (1,10-phenanthroline) lanthanum(III)]
trithiocyanate is a new compound that has shown high ability for
stopping the synthesis of DNA and also acting as a photosensitizer.
Nowadays, the radiation dose assessment resource (RADAR) method
is known as the most common method for absorbed dose calculation.
177Lu was produced by (n, gamma) reaction in a research reactor.
177Lu-PL3 was prepared in the optimized condition. The
radiochemical yield was checked by ITLC method. The
biodistribution of the complex was investigated by intravenously
injection to wild-type rats via their tail veins. In this study, the
absorbed dose of 177Lu-PL3 to human organs was estimated by
RADAR method. 177Lu was prepared with a specific activity of 2.6-3
GBq.mg-1 and radionuclide purity of 99.98 %. Final preparation of
the radiolabelled complex showed high radiochemical purity of >
99%. The results show that liver and spleen have received the highest
absorbed dose of 1.051 and 0.441 mSv/MBq, respectively. The
absorbed dose values for these two dose-limiting tissues suggest
more biological studies special in tumor-bearing animals.
Abstract: This article presents the main results of a numerical
investigation on the uncertainty of dynamic response of structures
with statistically correlated random damping Gamma distributed. A
computational method based on a Linear Statistical Model (LSM) is
implemented to predict second order statistics for the response of a
typical industrial building structure. The significance of random
damping with correlated parameters and its implications on the
sensitivity of structural peak response in the neighborhood of a
resonant frequency are discussed in light of considerable ranges of
damping uncertainties and correlation coefficients. The results are
compared to those generated using Monte Carlo simulation
techniques. The numerical results obtained show the importance of
damping uncertainty and statistical correlation of damping
coefficients when obtaining accurate probabilistic estimates of
dynamic response of structures. Furthermore, the effectiveness of the
LSM model to efficiently predict uncertainty propagation for
structural dynamic problems with correlated damping parameters is
demonstrated.
Abstract: Current study established for EEG signal analysis in
patients with language disorder. Language disorder can be defined as
meaningful delay in the use or understanding of spoken or written
language. The disorder can include the content or meaning of
language, its form, or its use. Here we applied Z-score, power
spectrum, and coherence methods to discriminate the language
disorder data from healthy ones. Power spectrum of each channel in
alpha, beta, gamma, delta, and theta frequency bands was measured.
In addition, intra hemispheric Z-score obtained by scoring algorithm.
Obtained results showed high Z-score and power spectrum in
posterior regions. Therefore, we can conclude that peoples with
language disorder have high brain activity in frontal region of brain
in comparison with healthy peoples. Results showed that high coherence correlates with irregularities
in the ERP and is often found during complex task, whereas low
coherence is often found in pathological conditions. The results of the
Z-score analysis of the brain dynamics showed higher Z-score peak
frequency in delta, theta and beta sub bands of Language Disorder
patients. In this analysis there were activity signs in both hemispheres
and the left-dominant hemisphere was more active than the right.
Abstract: Effects of nicotine on pre-partum body weight and
preimplantation embryonic development has been reported
previously. Present study was conducted to determine the effects of
annatto (Bixa orellana)-derived delta-tocotrienol (TCT) (with
presence of 10% gamma-TCT isomer) on the nicotine-induced
reduction in body weight and 8-cell embryonic growth in mice.
Twenty-four 6-8 weeks old (23-25g) female balb/c mice were
randomly divided into four groups (G1-G4; n=6). Those groups were
subjected to the following treatments for 7 consecutive days: G1
(control) were gavaged with 0.1 ml tocopherol stripped corn oil. G2
was subcutaneously (s.c.) injected with 3 mg/kg/day of nicotine. G3
received concurrent treatment of nicotine (3 mg/kg/day) and 60
mg/kg/day of δ-TCT mixture (contains 90% delta & 10% gamma
isomers) and G4 was given 60 mg/kg/day of δ-TCT mixture alone.
Body weights were recorded daily during the treatment. On Day 8,
females were superovulated with 5 IU Pregnant Mare’s Serum
Gonadotropin (PMSG) for 48 hours followed with 5 IU human
Chorionic Gonadotropin (hCG) before mated with males at the ratio
of 1:1. Females were sacrificed by cervical dislocation for embryo
collection 48 hours post-coitum. Collected embryos were cultured in
vitro. Results showed that throughout Day 1 to Day 7, the body
weight of nicotine treated group (G2) was significantly lower
(p
Abstract: Several embryonic cellular mechanism including cell
cycle, growth and apoptosis are regulated by phosphatidylinositol-3-
kinase (PI3K)/Akt signaling pathway. The goal of present study is to
determine the effects of annatto (Bixa orellana)-derived δ-tocotrienol
(δ-TCT) on the regulations of PI3K/Akt genes in murine morula.
Twenty four 6-8 week old (23-25g) female balb/c mice were
randomly divided into four groups (G1-G4; n=6). Those groups were
subjected to the following treatments for 7 consecutive days: G1
(control) received tocopherol stripped corn oil, G2 was given 60
mg/kg/day of δ-TCT mixture (contains 90% delta & 10% gamma
isomers), G3 was given 60 mg/kg/day of pure δ-TCT (>98% purity)
and G4 received 60 mg/kg/day α-TOC. On Day 8, females were
superovulated with 5 IU Pregnant Mare’s Serum Gonadotropin
(PMSG) for 48 hours followed with 5 IU human Chorionic
Gonadotropin (hCG) before mated with males at the ratio of 1:1.
Females were sacrificed by cervical dislocation for embryo collection
48 hours post-coitum. About fifty morulas from each group were
used in the gene expression analyses using Affymetrix QuantiGene
Plex 2.0 Assay. Present data showed a significant increase (p
Abstract: This study aimed to determine the possible protective effects of L‐carnitine against gentamicin‐induced nephrotoxicity. Forty male albino rats were divided into 4 groups (10 rats each); Group 1: normal control, group 2: induced nephrotoxicity (gentamicin 50 mg/kg/day S.C; 8 days), group 3: treated with L‐ carnitine (40 mg/kg/d SC for 12 days) and group 4: treated with L‐ carnitine 4 days before and for 8 days in concomitant with gentamicin. Gentamicin‐induced nephrotoxicity (group 2): caused significant increase in serum urea, creatinine, urinary N‐acetyl‐B‐D‐ glucosaminidase (NAG), gamma glutamyl transpeptidase (GGT), urinary total protein and kidney tissue malondialdehyde (MDA) with significant decrease in serum superoxide dismutase (SOD), serum catalase and creatinine clearance and marked tubular necrosis in the proximal convoluted tubules with interruption in the basement membrane around the necrotic tubule compared to the normal control group. L‐carnitine 4 days before and for 8 days in concomitant with gentamicin (group 4) offered marked decrease in serum urea, serum creatinine, urinary NAG, urinary GGT, urinary proteins and kidney tissue MDA, with marked increase in serum SOD, serum catalase and creatinine clearance with marked improvement in the tubular damage compared to gentamicin‐induced nephrotoxicity group. L‐carnitine administered for 12 days produced no change in the parameters mentioned above as compared to the normal control group. In conclusion: L‐carnitine could reduce most of the biochemical parameters and also improve the histopathological features of kidney asscociated with gentamicin induced‐nephrotoxicity.
Abstract: Many industrial materials like magnets need to be
tested for the radiation environment expected at linear colliders (LC)
where the accelerator and detectors will be subjected to large
influences of beta, neutron and gamma’s over their life Gamma
irradiation of the permanent sample magnets using a 60Co source was
investigated up to an absorbed dose of 700Mrad shows a negligible
effect on some magnetic properties of Nd-Fe-B. In this work it has
been tried to investigate the change of some important properties of
Barium hexa ferrite. Results showed little decreases of magnetic
properties at doses rang of 0.5 to 2.5 Mrad. But at the gamma
irradiation dose up to 10 Mrad it is showed a few increase of
properties. Also study of gamma irradiation of Nd-Fe-B showed
considerably increase of magnetic properties.
Abstract: A simple adaptive voice activity detector (VAD) is
implemented using Gabor and gammatone atomic decomposition of
speech for high Gaussian noise environments. Matching pursuit is
used for atomic decomposition, and is shown to achieve optimal
speech detection capability at high data compression rates for low
signal to noise ratios. The most active dictionary elements found by
matching pursuit are used for the signal reconstruction so that the
algorithm adapts to the individual speakers dominant time-frequency
characteristics. Speech has a high peak to average ratio enabling
matching pursuit greedy heuristic of highest inner products to isolate
high energy speech components in high noise environments. Gabor
and gammatone atoms are both investigated with identical
logarithmically spaced center frequencies, and similar bandwidths.
The algorithm performs equally well for both Gabor and gammatone
atoms with no significant statistical differences. The algorithm
achieves 70% accuracy at a 0 dB SNR, 90% accuracy at a 5 dB SNR
and 98% accuracy at a 20dB SNR using 30d B SNR as a reference
for voice activity.
Abstract: The changes of the optical and structural properties of
Bismuth-Boro-Tellurite glasses pre and post gamma irradiation were
studied. Six glass samples, with different composition [(TeO2)0.7
(B2O3)0.3]1-x (Bi2O3)x prepared by melt quenching method were
irradiated with 25kGy gamma radiation at room temperature. The
Fourier Transform Infrared Spectroscopy (FTIR) was used to explore
the structural bonding in the prepared glass samples due to exposure,
while UV-VIS Spectrophotometer was used to evaluate the changes
in the optical properties before and after irradiation. Gamma
irradiation causes profound changes in the peak intensity as shown by
FTIR spectra which is due to the breaking of the network bonding.
Before gamma irradiation, the optical band gap, Eg value decreased
from 2.44 eV to 2.15 eV with the addition of Bismuth content. The
value kept decreasing (from 2.18 eV to 2.00 eV) following exposure
to gamma radiation due to the increase of non-bridging oxygen
(NBO) and the increase of defect in the glass. In conclusion, the glass
with high content of Bi2O3 (0.30Bi) give smallest Eg and show less
changes in FTIR spectra after gamma irradiation which indicate that
this glass is more resistant to gamma radiation compared to other
glasses.
Abstract: High pressure turbine (HPT) blades of DV – 2 jet
engines are made from Ni – based superalloy. This alloy was
originally manufactured in the Soviet Union and referred as ŽS6K.
For improving alloy’s high temperature resistance are blades coated
with Al – Si diffusion layer. A regular operation temperature of HPT
blades vary from 705°C to 750°C depending on jet engine regime.
An overcrossing working temperature range causes degradation of
the protective coating as well as base material which microstructure
is formed by the gamma matrix and strengthening phase gamma
prime (forming small particles in the microstructure). Diffusion
processes inside the material during exposition of the material to high
temperatures causes mainly coarsening of the gamma prime particles,
thus decreasing its strengthening effect. Degradation of the Al – Si
coating caused its thickness growth. All the microstructure changes
and coating layer thickness growth results in decreasing of the turbine
blade operation lifetime.
Abstract: In this study, several crossplots of the P-impedance
with the lithology logs (gamma ray, neutron porosity, deep resistivity,
water saturation and Vp/Vs curves) were made in three available
wells, which were drilled in central part of the Blue Nile basin in
depths varies from 1460m to 1600m. These crossplots were
successful to discriminate between sand and shale when using PImpedance
values, and between the wet sand and the pay sand when
using both P-impedance and Vp/Vs together. Also some impedance
sections were converted to porosity sections using linear formula to
characterize the reservoir in terms of porosity. The used crossplots
were created on log resolution, while the seismic resolution can
identify only the reservoir, unless a 3D seismic angle stacks were
available; then it would be easier to identify the pay sand with great
confidence; through high resolution seismic inversion and
geostatistical approach when using P-impedance and Vp/Vs volumes.
Abstract: Evaluated nuclear decay data for the 217Po nuclide is
presented in the present work. These data include recommended
values for the half-life T1/2, α-, β-- and γ-ray emission energies and
probabilities. Decay data from 221Rn α and 217Bi β—decays are
presented. Q(α) has been updated based on the recent published work
of the Atomic Mass Evaluation AME2012. In addition, the logft
values were calculated using the Logft program from the ENSDF
evaluation package. Moreover, the total internal conversion electrons
and the K-shell to L-shell and L-shell to M-shell and to N-shell
conversion electrons ratios K/L, L/M and L/N have been calculated
using Bricc program. Meanwhile, recommendation values or the
multi-polarities have been assigned based on recently measurement
yield a better intensity balance at the 254 keV and 264 keV gamma
transitions.
Abstract: Macro invertebrates have been used to monitor
organic pollution in rivers and streams. Several biotic indices based
on macro invertebrates have been developed over the years including
the Biological Monitoring Working Party (BMWP). A new biotic
index, the Gammarus:Asellus ratio has been recently proposed as an
index of organic pollution. This study tested the validity of the
Gammarus:Asellus ratio as an index of organic pollution, by
examining the relationship between the Gammarus:Asellus ratio and
physical chemical parameters, and other biotic indices such as
BMWP and, Average Score Per Taxon (ASPT) from lakes and
streams at Markeaton Park, Allestree Park and Kedleston Hall,
Derbyshire. Macro invertebrates were sampled using the standard
five minute kick sampling techniques physical and chemical
environmental variables were obtained based on standard sampling
techniques. Eighteen sites were sampled, six sites from Markeaton
Park (three sites across the stream and three sites across the lake). Six
sites each were also sampled from Allestree Park and Kedleston Hall
lakes. The Gammarus:Asellus ratio showed an opposite significant
positive correlations with parameters indicative of organic pollution
such as the level of nitrates, phosphates, and calcium and also
revealed a negatively significant correlations with other biotic indices
(BMWP/ASPT). The BMWP score correlated positively significantly
with some water quality parameters such as dissolved oxygen and
flow rate, but revealed no correlations with other chemical
environmental variables. The BMWP score was significantly higher
in the stream than the lake in Markeaton Park, also The ASPT scores
appear to be significantly higher in the upper Lakes than the middle
and lower lakes. This study has further strengthened the use of
BMWP/ASPT score as an index of organic pollution. But additional
application is required to validate the use of Gammarus:Asellus as a
rapid bio monitoring tool.
Abstract: Food is widely packaged with plastic materials to
prevent microbial contamination and spoilage. Ionizing radiation is
widely used to sterilize the food-packaging materials. Sterilization by
γ-radiation causes degradation such as embrittlement, stiffening,
softening, discoloration, odour generation, and decrease in molecular
weight. Many antioxidants can prevent γ-degradation but most of
them are toxic. The migration of antioxidants to its environment
gives rise to major concerns in case of food packaging plastics. In
this attempt, we have aimed to utilize synergistic mixtures of
stabilizers which are approved for food-contact applications.
Ethylene-propylene-diene terpolymer has been melt-mixed with
hindered amine stabilizers (HAS), phenolic antioxidants and organophosphites
(hydroperoxide decomposer). Results were discussed by
comparing the stabilizing efficiency of mixtures with and without
phenol system. Among phenol containing systems where we mostly
observed discoloration due to the oxidation of hindered phenol, the
combination of secondary HAS, tertiary HAS, organo-phosphite and
hindered phenol exhibited improved stabilization efficiency than
single or binary additive systems. The mixture of secondary HAS and
tertiary HAS, has shown antagonistic effect of stabilization.
However, the combination of organo-phosphite with secondary HAS,
tertiary HAS and phenol antioxidants have been found to give
synergistic even at higher doses of Gamma-irradiation. The effects
have been explained through the interaction between the stabilizers.
After γ-irradiation, the consumption of oligomeric stabilizer
significantly depends on the components of stabilization mixture. The
effect of the organo-phosphite antioxidant on the overall stability has
been discussed.
Abstract: One of the most important tasks in the risk
management is the correct determination of probability of default
(PD) of particular financial subjects. In this paper a possibility of
determination of financial institution’s PD according to the creditscoring
models is discussed. The paper is divided into the two parts.
The first part is devoted to the estimation of the three different
models (based on the linear discriminant analysis, logit regression
and probit regression) from the sample of almost three hundred US
commercial banks. Afterwards these models are compared and
verified on the control sample with the view to choose the best one.
The second part of the paper is aimed at the application of the chosen
model on the portfolio of three key Czech banks to estimate their
present financial stability. However, it is not less important to be able
to estimate the evolution of PD in the future. For this reason, the
second task in this paper is to estimate the probability distribution of
the future PD for the Czech banks. So, there are sampled randomly
the values of particular indicators and estimated the PDs’ distribution,
while it’s assumed that the indicators are distributed according to the
multidimensional subordinated Lévy model (Variance Gamma model
and Normal Inverse Gaussian model, particularly). Although the
obtained results show that all banks are relatively healthy, there is
still high chance that “a financial crisis” will occur, at least in terms
of probability. This is indicated by estimation of the various quantiles
in the estimated distributions. Finally, it should be noted that the
applicability of the estimated model (with respect to the used data) is
limited to the recessionary phase of the financial market.
Abstract: Different services based on different switching
techniques in wireless networks leads to drastic changes in the
properties of network traffic. Because of these diversities in services,
network traffic is expected to undergo qualitative and quantitative
variations. Hence, assumption of traffic characteristics and the
prediction of network events become more complex for the wireless
networks. In this paper, the traffic characteristics have been studied
by collecting traces from the mobile switching centre (MSC). The
traces include initiation and termination time, originating node, home
station id, foreign station id. Traffic parameters namely, call interarrival
and holding times were estimated statistically. The results
show that call inter-arrival and distribution time in this wireless
network is heavy-tailed and follow gamma distributions. They are
asymptotically long-range dependent. It is also found that the call
holding times are best fitted with lognormal distribution. Based on
these observations, an analytical model for performance estimation is
also proposed.
Abstract: Brain functional networks based on resting-state EEG
data were compared between patients with mild Alzheimer’s disease
(mAD) and matched patients with amnestic subtype of mild cognitive
impairment (aMCI). We integrated the time–frequency cross mutual
information (TFCMI) method to estimate the EEG functional
connectivity between cortical regions and the network analysis based
on graph theory to further investigate the alterations of functional
networks in mAD compared with aMCI group. We aimed at
investigating the changes of network integrity, local clustering,
information processing efficiency, and fault tolerance in mAD brain
networks for different frequency bands based on several topological
properties, including degree, strength, clustering coefficient, shortest
path length, and efficiency. Results showed that the disruptions of
network integrity and reductions of network efficiency in mAD
characterized by lower degree, decreased clustering coefficient, higher
shortest path length, and reduced global and local efficiencies in the
delta, theta, beta2, and gamma bands were evident. The significant
changes in network organization can be used in assisting
discrimination of mAD from aMCI in clinical.