Abstract: This study was aimed to measure effective transverse
relaxation rates (R2*) in the liver and muscle of normal New Zealand
White (NZW) rabbits. R2* relaxation rate has been widely used in
various hepatic diseases for iron overload by quantifying iron contents
in liver. R2* relaxation rate is defined as the reciprocal of T2*
relaxation time and mainly depends on the constituents of tissue.
Different tissues would have different R2* relaxation rates. The signal
intensity decay in Magnetic resonance imaging (MRI) may be
characterized by R2* relaxation rates. In this study, a 1.5T GE Signa
HDxt whole body MR scanner equipped with an 8-channel high
resolution knee coil was used to observe R2* values in NZW rabbit’s
liver and muscle. Eight healthy NZW rabbits weighted 2 ~ 2.5 kg were
recruited. After anesthesia using Zoletil 50 and Rompun 2% mixture,
the abdomen of rabbit was landmarked at the center of knee coil to
perform 3-plane localizer scan using fast spoiled gradient echo
(FSPGR) pulse sequence. Afterwards, multi-planar fast gradient echo
(MFGR) scans were performed with 8 various echo times (TEs) to
acquire images for R2* measurements. Regions of interest (ROIs) at
liver and muscle were measured using Advantage workstation.
Finally, the R2* was obtained by a linear regression of ln(sı) on TE.
The results showed that the longer the echo time, the smaller the signal
intensity. The R2* values of liver and muscle were 44.8 ± 10.9 s-1 and
37.4 ± 9.5 s-1, respectively. It implies that the iron concentration of
liver is higher than that of muscle. In conclusion, the more the iron
contents in tissue, the higher the R2*. The correlations between R2*
and iron content in NZW rabbits might be valuable for further
exploration.
Abstract: Introduction: Whole-Body Vibration (WBV) uses
high frequency mechanical stimuli generated by a vibration plate and
transmitted through bone, muscle and connective tissues to the whole
body. Research has shown that long-term vibration-plate training
improves neuromuscular facilitation, especially in afferent neural
pathways, responsible for the conduction of vibration and
proprioceptive stimuli, muscle function, balance and proprioception.
Some researchers suggest that the vibration stimulus briefly inhibits
the conduction of afferent signals from proprioceptors and can
interfere with the maintenance of body balance. The aim of this study
was to evaluate the influence of a single set of exercises associated
with whole-body vibration on the joint position sense and body
balance. Material and methods: The study enrolled 55 people aged
19-24 years. These individuals were randomly divided into a test
group (30 persons) and a control group (25 persons). Both groups
performed the same set of exercises on a vibration plate. The
following vibration parameters: frequency of 20Hz and amplitude of
3mm, were used in the test group. The control group performed
exercises on the vibration plate while it was off. All participants were
instructed to perform six dynamic exercises lasting 30 seconds each
with a 60-second period of rest between them. The exercises involved
large muscle groups of the trunk, pelvis and lower limbs.
Measurements were carried out before and immediately after
exercise. Joint position sense (JPS) was measured in the knee joint
for the starting position at 45° in an open kinematic chain. JPS error
was measured using a digital inclinometer. Balance was assessed in a
standing position with both feet on the ground with the eyes open and
closed (each test lasting 30 sec). Balance was assessed using Matscan
with FootMat 7.0 SAM software. The surface of the ellipse of
confidence and front-back as well as right-left swing were measured
to assess balance. Statistical analysis was performed using Statistica
10.0 PL software. Results: There were no significant differences
between the groups, both before and after the exercise (p> 0.05). JPS
did not change in both the test (10.7° vs. 8.4°) and control groups
(9.0° vs. 8.4°). No significant differences were shown in any of the
test parameters during balance tests with the eyes open or closed in
both the test and control groups (p> 0.05). Conclusions: 1.
Deterioration in proprioception or balance was not observed
immediately after the vibration stimulus. This suggests that vibrationinduced
blockage of proprioceptive stimuli conduction can have only
a short-lasting effect that occurs only as long as a vibration stimulus
is present. 2. Short-term use of vibration in treatment does not impair
proprioception and seems to be safe for patients with proprioceptive
impairment. 3. These results need to be supplemented with an
assessment of proprioception during the application of vibration
stimuli. Additionally, the impact of vibration parameters used in the
exercises should be evaluated.
Abstract: NiFe2O4 (nickel ferrite), ZnFe2O4 (zinc ferrite) and
Ni0.5Zn0.5Fe2O4 (nickel-zinc ferrite) were prepared by
mechanochemical route in a planetary ball mill starting from mixture
of the appropriate quantities of the Ni(OH)2/Fe(OH)3,
Zn(OH)2/Fe(OH)3 and Ni(OH)2/Zn(OH)2/Fe(OH)3 hydroxide
powders. In order to monitor the progress of chemical reaction and
confirm phase formation, powder samples obtained after 25 h, 18 h
and 10 h of milling were characterized by X-ray diffraction (XRD),
transmission electron microscopy (TEM), IR, Raman and Mössbauer
spectroscopy. It is shown that the soft mechanochemical method, i.e.
mechanochemical activation of hydroxides, produces high quality
single phase ferrite samples in much more efficient way. From the IR
spectroscopy of single phase samples it is obvious that energy of
modes depends on the ratio of cations. It is obvious that all samples
have more than 5 Raman active modes predicted by group theory in
the normal spinel structure. Deconvolution of measured spectra
allows one to conclude that all complex bands in the spectra are made
of individual peaks with the intensities that vary from spectrum to
spectrum. The deconvolution of Raman spectra allows to separate
contributions of different cations to a particular type of vibration and
to estimate the degree of inversion.
Abstract: Obturator Foramen is a specific structure in Pelvic
bone images and recognition of it is a new concept in medical image
processing. Moreover, segmentation of bone structures such as
Obturator Foramen plays an essential role for clinical research in
orthopedics. In this paper, we present a novel method to analyze the
similarity between the substructures of the imaged region and a hand
drawn template as a preprocessing step for computation of Pelvic
bone rotation on hip radiographs. This method consists of integrated
usage of Marker-controlled Watershed segmentation and Zernike
moment feature descriptor and it is used to detect Obturator Foramen
accurately. Marker-controlled Watershed segmentation is applied to
separate Obturator Foramen from the background effectively. Then,
Zernike moment feature descriptor is used to provide matching
between binary template image and the segmented binary image for
final extraction of Obturator Foramens. Finally, Pelvic bone rotation
rate calculation for each hip radiograph is performed automatically to
select and eliminate hip radiographs for further studies which depend
on Pelvic bone angle measurements. The proposed method is tested
on randomly selected 100 hip radiographs. The experimental results
demonstrated that the proposed method is able to segment Obturator
Foramen with 96% accuracy.
Abstract: Background: To compare the thinning patterns of the
ganglion cell-inner plexiform layer (GCIPL) and peripapillary retinal
nerve fiber layer (pRNFL) as measured using Cirrus high-definition
optical coherence tomography (HD-OCT) in patients with visual field
(VF) defects that respect the vertical meridian. Methods: Twenty eyes of eleven patients with VF defects that
respect the vertical meridian were enrolled retrospectively. The
thicknesses of the macular GCIPL and pRNFL were measured using
Cirrus HD-OCT. The 5% and 1% thinning area index (TAI) was
calculated as the proportion of abnormally thin sectors at the 5% and
1% probability level within the area corresponding to the affected VF.
The 5% and 1% TAI were compared between the GCIPL and pRNFL
measurements. Results: The color-coded GCIPL deviation map showed a
characteristic vertical thinning pattern of the GCIPL, which is also
seen in the VF of patients with brain lesions. The 5% and 1% TAI
were significantly higher in the GCIPL measurements than in the
pRNFL measurements (all P < 0.01). Conclusions: Macular GCIPL analysis clearly visualized a
characteristic topographic pattern of retinal ganglion cell (RGC) loss
in patients with VF defects that respect the vertical meridian, unlike
pRNFL measurements. Macular GCIPL measurements provide more
valuable information than pRNFL measurements for detecting the
loss of RGCs in patients with retrograde degeneration of the optic
nerve fibers.
Abstract: This paper develops a multiple channel assignment
model, which allows to take advantage of spectrum opportunities in
cognitive radio networks in the most efficient way. The developed
scheme allows making several assignments of available and
frequency adjacent channel, which require a bigger bandwidth, under
an equality environment. The hybrid assignment model it is made by
two algorithms, one that makes the ranking and selects available
frequency channels and the other one in charge of establishing the
Max-Min Fairness for not restrict the spectrum opportunities for all
the other secondary users, who also claim to make transmissions.
Measurements made were done for average bandwidth, average
delay, as well as fairness computation for several channel
assignments. Reached results were evaluated with experimental
spectrum occupational data from captured GSM frequency band. The
developed model shows evidence of improvement in spectrum
opportunity use and a wider average transmission bandwidth for each
secondary user, maintaining equality criteria in channel assignment.
Abstract: The Greater Athens Area (GAA) faces photochemical
and particulate pollution episodes as a result of the combined effects
of local pollutant emissions, regional pollution transport, synoptic
circulation and topographic characteristics. The area has undergone
significant changes since the Athens 2004 Olympic Games because
of large scale infrastructure works that lead to the shift of population
to areas previously characterized as rural, the increase of the traffic
fleet and the operation of highways. However, few recent modelling
studies have been performed due to the lack of an accurate, updated
emission inventory. The photochemical modelling system
MM5/CAMx was applied in order to study the photochemical and
particulate pollution characteristics above the GAA for two distinct
ten-day periods in the summer of 2006 and 2010, where air pollution
episodes occurred. A new updated emission inventory was used
based on official data. Comparison of modeled results with
measurements revealed the importance and accuracy of the new
Athens emission inventory as compared to previous modeling
studies. The model managed to reproduce the local meteorological
conditions, the daily ozone and particulates fluctuations at different
locations across the GAA. Higher ozone levels were found at
suburban and rural areas as well as over the sea at the south of the
basin. Concerning PM10, high concentrations were computed at the
city centre and the southeastern suburbs in agreement with measured
data. Source apportionment analysis showed that different sources
contribute to the ozone levels, the local sources (traffic, port
activities) affecting its formation.
Abstract: The present study deals with the characterization of
CrSiN coatings obtained by PVD magnetron sputtering systems.
CrSiN films were deposited with different Si contents, in order to
check the effect of at.% variation on the different properties of the
Cr–N system. Coatings were characterized by scanning electron
microscopy (SEM) for thickness measurements, X-ray diffraction.
Surface morphology and the roughness characteristics were explored
using AFM, Mechanicals properties, elastic and plastic deformation
resistance of thin films were investigated using nanoindentation test. We observed that the Si addition improved the hardness and the
Young’s modulus of the Cr–N system. Indeed, the hardness value is
18,56 GPa for CrSiN coatings. Besides, the Young’s modulus value
is 224,22 GPa for CrSiN coatings for Si content of 1.2 at.%.
Abstract: The advancements in technology allow the
development of a new system that can continuously measure surface
soil erosion. Continuous soil erosion measurements are required in
order to comprehend the erosional processes and propose effective
and efficient conservation measures to mitigate surface erosion.
Mitigating soil erosion, especially in Mediterranean countries such as
Greece, is essential in order to maintain environmental and
agricultural sustainability. In this paper, we present the Automated
Soil Erosion Monitoring System (ASEMS) that measures surface soil
erosion along with other factors that impact erosional process.
Specifically, this system measures ground level changes (surface soil
erosion), rainfall, air temperature, soil temperature, and soil moisture.
Another important innovation is that the data will be collected by
remote communication. In addition, stakeholder’s awareness is a key
factor to help reduce any environmental problem. The different
dissemination activities that were utilized are described. The overall
outcomes were the development of a new innovative system that can
measure erosion very accurately. These data from the system help
study the process of erosion and find the best possible methods to
reduce erosion. The dissemination activities enhance the stakeholders
and public's awareness on surface soil erosion problems and will lead
to the adoption of more effective soil erosion conservation practices
in Greece.
Abstract: This study presents a kinematic positioning approach
that uses a global positioning system (GPS) buoy for precise ocean
surface monitoring. The GPS buoy data from the two experiments are
processed using an accurate, medium-range differential kinematic
technique. In each case, the data from a nearby coastal site are
collected at a high rate (1 Hz) for more than 24 hours, and
measurements are conducted in neighboring tidal stations to verify
the estimated sea surface heights. The GPS buoy kinematic
coordinates are estimated using epoch-wise pre-elimination and a
backward substitution algorithm. Test results show that centimeterlevel
accuracy can be successfully achieved in determining sea
surface height using the proposed technique. The centimeter-level
agreement between the two methods also suggests the possibility of
using this inexpensive and more flexible GPS buoy equipment to
enhance (or even replace) current tidal gauge stations.
Abstract: Wicking and evaporation of water in porous knitted fabrics is investigated by combining experimental and analytical approaches: The standard wicking model from Lucas and Washburn is enhanced to account for evaporation and gravity effects. The goal is to model the effect of gravity and evaporation on wicking using simple analytical expressions and investigate the influence of fabrics geometrical parameters, such as porosity and thickness on evaporation impact on maximum reachable height values. The results show that fabric properties have a significant influence on evaporation effect. In this paper, an experimental study of determining water kinetics from different knitted fabrics were gravimetrically investigated permitting the measure of the mass and the height of liquid rising in fabrics in various atmospheric conditions. From these measurements, characteristic pore parameters (capillary radius and permeability) can be determined.
Abstract: Objectives: To determine the nutritional status and
risk factors associated with women practicing geophagia in QwaQwa,
South Africa. Materials and Methods: An observational epidemiological study
design was adopted which included an exposed (geophagia) and nonexposed
(control) group. A food frequency questionnaire, anthropometric measurements and blood sampling were applied to
determine nutritional status of participants. Logistic regression
analysis was performed in order to identify factors that were likely to
be associated with the practice of geophagia. Results: The mean total energy intake for the geophagia group (G)
and control group (C) were 10324.31 ± 2755.00 kJ and 10763.94 ±
2556.30 kJ respectively. Both groups fell within the overweight
category according to the mean Body Mass Index (BMI) of each
group (G= 25.59 kg/m2; C= 25.14 kg/m2). The mean serum iron
levels of the geophagia group (6.929 μmol/l) were significantly lower
than that of the control group (13.75 μmol/l) (p = 0.000). Serum
transferrin (G=3.23g/l; C=2.7054g/l) and serum transferrin saturation
(G=8.05%; C=18.74%) levels also differed significantly between
groups (p=0.00). Factors that were associated with the practice of
geophagia included haemoglobin (Odds ratio (OR):14.50), serumiron
(OR: 9.80), serum-ferritin (OR: 3.75), serum-transferrin (OR:
6.92) and transferrin saturation (OR: 14.50). A significant negative
association (p=0.014) was found between women who were wageearners
and those who were not wage-earners and the practice of
geophagia (OR: 0.143; CI: 0.027; 0.755). These findings seem to
indicate that a permanent income may decrease the likelihood of
practising geophagia. Key Findings: Geophagia was confirmed to be a risk factor for
iron deficiency in this community. The significantly strong
association between geophagia and iron deficiency emphasizes the
importance of identifying the practice of geophagia in women,
especially during their child bearing years.
Abstract: An industrial system for the production of white
liquor of a paper industry, Klabin Paraná Papéis, formed by ten
reactors was modeled, simulated, and analyzed. The developed model
considered possible water losses by evaporation and reaction, in
addition to variations in volumetric flow of lime mud across the
reactors due to composition variations. The model predictions agreed
well with the process measurements at the plant and the results
showed that the slaking reaction is nearly complete at the third
causticizing reactor, while causticizing ends by the seventh reactor.
Water loss due to slaking reaction and evaporation occurs more
pronouncedly in the slaking reaction than in the final causticizing
reactors; nevertheless, the lime mud flow remains nearly constant
across the reactors.
Abstract: An experimental study with four different types of bed
conditions was carried out to understand the effect of roughness in
open channel flow at two different Reynolds numbers. The bed
conditions include a smooth surface and three different roughness
conditions, which were generated using sand grains with a median
diameter of 2.46 mm. The three rough conditions include a surface
with distributed roughness, a surface with continuously distributed
roughness and a sand bed with a permeable interface. A commercial
two-component fibre-optic LDA system was used to conduct the
velocity measurements. The variables of interest include the mean
velocity, turbulence intensity, correlation between the streamwise and
the wall normal turbulence, Reynolds shear stress and velocity triple
products. Quadrant decomposition was used to extract the magnitude
of the Reynolds shear stress of the turbulent bursting events. The
effect of roughness was evident throughout the flow depth. The
results show that distributed roughness has the greatest roughness
effect followed by the sand bed and the continuous roughness.
Compared to the smooth bed, the streamwise turbulence intensity
reduces but the vertical turbulence intensity increases at a location
very close to the bed due to the introduction of roughness. Although
the same sand grain is used to create the three different rough bed
conditions, the difference in the turbulence intensity is an indication
that the specific geometry of the roughness has an influence on
turbulence structure.
Abstract: Heart is the most important part in the body of living
organisms. It affects and is affected by any factor in the body.
Therefore, it is a good detector for all conditions in the body. Heart
signal is a non-stationary signal; thus, it is utmost important to study
the variability of heart signal. The Heart Rate Variability (HRV) has
attracted considerable attention in psychology, medicine and has
become important dependent measure in psychophysiology and
behavioral medicine. The standards of measurements, physiological
interpretation and clinical use for HRV that are most often used were
described in many researcher papers, however, remain complex
issues are fraught with pitfalls. This paper presents one of the nonlinear
techniques to analyze HRV. It discusses many points like, what
Poincaré plot is and how Poincaré plot works; also, Poincaré plot's
merits especially in HRV. Besides, it discusses the limitation of
Poincaré cause of standard deviation SD1, SD2 and how to overcome
this limitation by using complex correlation measure (CCM). The
CCM is most sensitive to changes in temporal structure of the
Poincaré plot as compared toSD1 and SD2.
Abstract: The current-voltage (I-V) characteristics of Pd/n-GaN Schottky barrier were studied at temperatures over room temperature (300-470K). The values of ideality factor (n), zero-bias barrier height (φB0), flat barrier height (φBF) and series resistance (Rs) obtained from I-V-T measurements were found to be strongly temperature dependent while (φBo) increase, (n), (φBF) and (Rs) decrease with increasing temperature. The apparent Richardson constant was found to be 2.1x10-9 Acm-2K-2 and mean barrier height of 0.19 eV. After barrier height inhomogeneities correction, by assuming a Gaussian distribution (GD) of the barrier heights, the Richardson constant and the mean barrier height were obtained as 23 Acm-2K-2 and 1.78eV, respectively. The corrected Richardson constant was very closer to theoretical value of 26 Acm-2K-2.
Abstract: The apportionment method is used by many countries, to calculate the distribution of seats in political bodies. For example, this method is used in the United States (U.S.) to distribute house seats proportionally based on the population of the electoral district. Famous apportionment methods include the divisor methods called the Adams Method, Dean Method, Hill Method, Jefferson Method and Webster Method. Sometimes the results from the implementation of these divisor methods are unfair and include errors. Therefore, it is important to examine the optimization of this method by using a bias measurement to figure out precise and fair results. In this research we investigate the bias of divisor methods in the U.S. Houses of Representatives toward large and small states by applying the Stolarsky Mean Method. We compare the bias of the apportionment method by using two famous bias measurements: the Balinski and Young measurement and the Ernst measurement. Both measurements have a formula for large and small states. The Third measurement however, which was created by the researchers, did not factor in the element of large and small states into the formula. All three measurements are compared and the results show that our measurement produces similar results to the other two famous measurements.
Abstract: Due to the interference effects, the intrinsic
aerodynamic parameters obtained from the individual component
testing are always fundamentally different than those obtained for
complete model testing. Consideration and limitation for such testing
need to be taken into account in any design work related to the
component buildup method. In this paper, the scaled model of a
straight rectangular canard of a hybrid buoyant aircraft is tested at 50
m/s in IIUM-LSWT (Low Speed Wind Tunnel). Model and its
attachment with the balance are kept rigid to have results free from
the aeroelastic distortion. Based on the velocity profile of the test
section’s floor; the height of the model is kept equal to the
corresponding boundary layer displacement. Balance measurements
provide valuable but limited information of overall aerodynamic
behavior of the model. Zero lift coefficient is obtained at -2.2o and
the corresponding drag coefficient was found to be less than that at
zero angle of attack. As a part of the validation of low fidelity tool,
plot of lift coefficient plot was verified by the experimental data and
except the value of zero lift coefficients, the overall trend has under
predicted the lift coefficient. Based on this comparative study, a
correction factor of 1.36 is proposed for lift curve slope obtained
from the panel method.
Abstract: In this paper we present the design of an optical
device based on a Herriott multi-pass cell fabricated on a small sized
acrylic slab for heat flux measurements using the deflection of a laser
beam propagating inside the cell. The beam deflection is produced by
the heat flux conducted to the acrylic slab due to a gradient in the
refractive index. The use of a long path cell as the sensitive element
in this measurement device, gives the possibility of high sensitivity
within a small size device. We present the optical design as well as
some experimental results in order to validate the device’s operation
principle.
Abstract: High temperature Fischer-Tropsch synthesis process
use fixed fluidized bed as a reactor. In order to understand the flow
behavior in the fluidized bed better, the research of how the radial
velocity affects the entire flow field is necessary. Laser Doppler
Velocimetry (LDV) was used to study the radial velocity distribution
along the diameter direction of the cross-section of the particle in a
fixed fluidized bed. The velocity in the cross-section is fluctuating
within a small range. The direction of the speed is a random
phenomenon. In addition to r/R is 1, the axial velocity are more than 6
times of the radial velocity, the radial velocity has little impact on the
axial velocity in a fixed fluidized bed.