Abstract: This study was designed for assessment of 3 types of Cysteine protease inhibitors (CPIs) fluromethylketone (FMK), vinyl sulfone (VS) and sodium nitro prussid (SNP), to define which of them is the best for curing S. mansoni infection in mice? In vitro, treated S. mansoni adult worms recorded a mortality rate after 1 hr of exposure to 500 ppm of FMK, VS and SNP as 75, 70 and 60%, respectively. FMK+PZQ treatment recorded the maximum reduction in worm burden (97.2% at 5 wk PI). VS treatment alone or combined with PZQ increases IgM, total IgG, IgG2 and IgG4 levels. In EM study, the completely implanted spines were reported in the degenerated tegument of adult worms in all groups treated with CPIs. VS+PZQ Treatment increased Igs levels but, its effect was different on worm reduction. So, it is not enough to eliminate the infection and FMK+PZQ considered the antischistosomicidal drug of choice.
Abstract: This paper deals with the modified wireless power transmission system for biomedical implanted devices. The system consists of efficient class-E power amplifier and inductive power links based on spiral circular transmitter and receiver coils. The model of the class-E power amplifier operated with 13.56 MHz is designed, discussed and analyzed in which it is achieved 87.2% of efficiency. The inductive coupling method is used to achieve link efficiency up to 73% depending on the electronic remote system resistance. The improved system powered with 3.3 DC supply and the voltage across the transmitter side is 40 V whereas, cross the receiver side is 12 V which is rectified to meet the implanted micro-system circuit requirements. The system designed and simulated by NI MULTISIM 11.02.
Abstract: Chitosan (CH) material reinforced by bioactive glass (46S6) was fabricated. 46S6 containing 17% wt% CH was studied in vitro and in vivo. Physicochemical techniques, such as Fourier transform infrared spectroscopy (FT-IR), coupled plasma optical emission spectrometry (ICP-OES) analysis were used. The behavior of 46S6CH17 was studied by measuring the in situ pH in a SBF solution. The 46S6CH17 was implanted in the rat femoral condyl. In vitro 46S6CH17 gave an FTIR - spectrum in which three absorption bands with the maxima at 565, 603 and 1039cm-1 after 3 days of soaking in physiological solution. They are assigned to stretching vibrations of PO4^3- group in phosphate crystalline. Moreover, the pH measurement was decreased in the SBF solution. The stability of the calcium phosphate precipitation depended on the pH value. In vivo, a rise in the Ca and phosphate P ions concentrations in the implanted microenvironment was determined.
Abstract: The tribological outcomes of micro dent are found to be outstanding in many engineering and natural surfaces. Ceramic (Al2O3) is considered one of the most potential material to bearing surfaces particularly, artificial hip or knee implant. A well-defined micro dent on alumina oxide interface could further decrease friction and wear rate, thus increase their stability and durability. In this study we fabricated circular micro dent surface profiles (Dia: 400µm, Depth 20µm, P: 1.5mm; Dia: 400µm, Depth 20µm, P: 2mm) on pure Al2O3 (99.6%) substrate by using a micro tool machines. A preliminary tribological experiment was carried out to compare friction coefficient of these fabricated dent surfaces with that of non-textured surfaces. The experiment was carried on well know pin-on-disk specimens while other experimental parameters such as hertz pressure, speed, lubrication, and temperature were maintained to standard of simulated hip joints condition. The experiment results revealed that micro dent surface texture reduced 15%, 8% and 4% friction coefficient under 0.132,0.162, 0.187 GPa contact pressure respectively. Since this is a preliminary tribological study, we will pursue further experiments considering higher ranges of dent profiles and longer run experiments. However, the preliminary results confirmed the suitability of fabricating dent profile to ceramic surfaces by using micro tooling, and also their improved tribological performance in simulated hip joints.
Abstract: In biomedical implant field, a new formula is given
for the study of Radio Frequency power attenuation by simultaneous
effects of side and angular misalignment of the supply/data transfer
coils. A confrontation with the practical measurements done into a
Faraday cage, allowed a checking of the obtained theoretical results.
The DC supply systems without material connection and the data
transmitters used in the case of biomedical implants, can be well
dimensioned by taking into account the possibility of power
attenuation by misalignment of transfer coils
Abstract: Retinal prostheses have been successful in eliciting
visual responses in implanted subjects. As these prostheses progress,
one of their major limitations is the need for increased resolution. As
an alternative to increasing the number of electrodes, virtual
electrodes may be used to increase the effective resolution of current
electrode arrays. This paper presents a virtual electrode technique
based upon time-offsets between stimuli. Two adjacent electrodes are
stimulated with identical pulses with too short of pulse widths to
activate a neuron, but one has a time offset of one pulse width. A
virtual electrode of twice the pulse width was then shown to appear in
the center, with a total width capable of activating a neuron. This can
be used in retinal implants by stimulating electrodes with pulse
widths short enough to not elicit responses in neurons, but with their
combined pulse width adequate to activate a neuron in between them.
Abstract: In mammalian reproductive tract, the oviduct secretes
huge number of growth factors and cytokines that create an optimal
micro-environment for the initial stages of preimplantation embryos.
Secretion of these growth factors is stage-specific. Among them,
VEGF is a potent mitogen for vascular endothelium and stimulates
vascular permeability. Apart from angiogenesis, VEGF in the oviduct
may be involved in regulating the oocyte maturation and subsequent
developmental process during embryo production in vitro. In
experiment 1, to evaluate the effect of VEGF during IVM of porcine
COC and subsequent developmental ability after PA and SCNT. The
results from these experiments indicated that maturation rates among
the different VEGF concentrations were not significant different. In
experiment 2, total intracellular GSH concentrations of oocytes
matured with VEGF (5-50 ng/ml) were increased significantly
compared to a control and VEGF group (500 ng/ml). In experiment 3,
the blastocyst formation rates and total cell number per blastocyst
after parthenogenesis of oocytes matured with VEGF (5-50 ng/ml)
were increased significantly compared to a control and VEGF group
(500 ng/ml). Similarly, in experiment 4, the blastocyst formation rate
and total cell number per blastocyst after SCNT and IVF of oocytes
matured with VEGF (5 ng/ml) were significantly higher than that of
oocytes matured without VEGF group. In experiment 5, at 10 hour
after the onset of IVF, pronuclear formation rate was evaluated.
Monospermy was significantly higher in VEGF-matured oocytes than
in the control, and polyspermy and sperm penetration per oocyte
were significantly higher in the control group than in the VEGFmatured
oocytes. Supplementation with VEGF during IVM
significantly improved male pronuclear formation as compared with
the control. In experiment 6, type III cortical granule distribution in
oocytes was more common in VEGF-matured oocytes than in the
control. In conclusion, the present study suggested that
supplementation of VEGF during IVM may enhance the
developmental potential of porcine in vitro embryos through increase
of the intracellular GSH level, higher MPN formation and increased
fertilization rate as a consequence of an improved cytoplasmic
maturation.
Abstract: This paper presents a novel method for inferring the
odor based on neural activities observed from rats- main olfactory
bulbs. Multi-channel extra-cellular single unit recordings were done
by micro-wire electrodes (tungsten, 50μm, 32 channels) implanted in
the mitral/tufted cell layers of the main olfactory bulb of anesthetized
rats to obtain neural responses to various odors. Neural response
as a key feature was measured by substraction of neural firing rate
before stimulus from after. For odor inference, we have developed a
decoding method based on the maximum likelihood (ML) estimation.
The results have shown that the average decoding accuracy is about
100.0%, 96.0%, 84.0%, and 100.0% with four rats, respectively. This
work has profound implications for a novel brain-machine interface
system for odor inference.
Abstract: Human heart valves diseased by congenital heart
defects, rheumatic fever, bacterial infection, cancer may cause stenosis
or insufficiency in the valves. Treatment may be with medication but
often involves valve repair or replacement (insertion of an artificial
heart valve). Bileaflet mechanical heart valves (BMHVs) are widely
implanted to replace the diseased heart valves, but still suffer from
complications such as hemolysis, platelet activation, tissue
overgrowth and device failure. These complications are closely related
to both flow characteristics through the valves and leaflet dynamics. In
this study, the physiological flow interacting with the moving leaflets
in a bileaflet mechanical heart valve (BMHV) is simulated with a
strongly coupled implicit fluid-structure interaction (FSI) method
which is newly organized based on the Arbitrary-Lagrangian-Eulerian
(ALE) approach and the dynamic mesh method (remeshing) of
FLUENT. The simulated results are in good agreement with previous
experimental studies. This study shows the applicability of the present
FSI model to the complicated physics interacting between fluid flow
and moving boundary.
Abstract: A major challenge in biomaterials research is the
regulation of protein adsorption which is a key factor for controlling
the subsequent cell adhesion at implant surfaces. The aim of the
present study was to control the adsorption of fibronectin (FN) and
the attachment of MG-63 osteoblasts with an electronic
nanostructure. Shallow doping line lattices with a period of 260 nm
were produced for this purpose by implantation of phosphorous in
silicon wafers. Protein coverage was determined after incubating the
substrate with FN by means of an immunostaining procedure and the
measurement of the fluorescence intensity with a TECAN analyzer.
We observed an increased amount of adsorbed FN on the
nanostructure compared to control substrates. MG-63 osteoblasts
were cultivated for 24h on FN-incubated substrates and their
morphology was assessed by SEM. Preferred orientation and
elongation of the cells in direction of the doping lattice lines was
observed on FN-coated nanostructures.
Abstract: Tumor cells have an invasive and metastatic phenotype
that is the main cause of death for cancer patients. Tumor
establishment and penetration consists of a series of complex
processes involving multiple changes in gene expression. In this study,
intraperitoneal administration of a high concentration of ascorbic acid
inhibited tumor establishment and decreased tumor mass in BALB/C
mice implanted with S-180 sarcoma cancer cells. To identify proteins
involved in the ascorbic acid-mediated inhibition of tumor
progression, changes in the tumor proteome associated with ascorbic
acid treatment of BALB/C mice implanted with S-180 were
investigated using two-dimensional gel electrophoresis and mass
spectrometry. Twenty protein spots were identified whose expression
was different between control and ascorbic acid treatment groups.
Abstract: In a transcutanious inductive coupling of a biomedical
implant, a new formula is given for the study of the Radio Frequency
power attenuation by the biological tissue. The loss of the signal
power is related to its interaction with the biological tissue and the
composition of this one. A confrontation with the practical
measurements done with a synthetic muscle into a Faraday cage,
allowed a checking of the obtained theoretical results. The
supply/data transfer systems used in the case of biomedical implants,
can be well dimensioned by taking in account this type of power
attenuation.
Abstract: Carriers scattering in the inversion channel of n-
MOSFET dominates the drain current. This paper presents an effective
electron mobility model for the pocket implanted nano scale
n-MOSFET. The model is developed by using two linear pocket
profiles at the source and drain edges. The channel is divided into
three regions at source, drain and central part of the channel region.
The total number of inversion layer charges is found for these three
regions by numerical integration from source to drain ends and the
number of depletion layer charges is found by using the effective
doping concentration including pocket doping effects. These two
charges are then used to find the effective normal electric field,
which is used to find the effective mobility model incorporating the
three scattering mechanisms, such as, Coulomb, phonon and surface
roughness scatterings as well as the ballistic phenomena for the
pocket implanted nano-scale n-MOSFET. The simulation results show
that the derived mobility model produces the same results as found
in the literatures.
Abstract: This paper presents the doping profile measurement
and characterization technique for the pocket implanted nano scale
n-MOSFET. Scanning capacitance microscopy and atomic force
microscopy have been used to image the extent of lateral dopant
diffusion in MOS structures. The data are capacitance vs. voltage
measurements made on a nano scale device. The technique is nondestructive
when imaging uncleaved samples. Experimental data from
the published literature are presented here on actual, cleaved device
structures which clearly indicate the two-dimensional dopant profile
in terms of a spatially varying modulated capacitance signal. Firstorder
deconvolution indicates the technique has much promise for
the quantitative characterization of lateral dopant profiles. The pocket
profile is modeled assuming the linear pocket profiles at the source
and drain edges. From the model, the effective doping concentration
is found to use in modeling and simulation results of the various
parameters of the pocket implanted nano scale n-MOSFET. The
potential of the technique to characterize important device related
phenomena on a local scale is also discussed.
Abstract: The State of Rio de Janeiro, Brazil, will hold two important events in the nearby future. In 2014 it will have the final game of the Football World Cup, and in 2016 it will be holding the Olympic Games. Therefore, the public transportation system (mainly buses) is of a major concern to the Rio de Janeiro State authorities-. The main objective of this work is to compare the quality of service of the bus companies operating in the cities of ItaperunaandCampos, both cities situated in the state of Rio de Janeiro, Brazil. The outcome of thiscomparison, based on the opinion of the bus users, has shownthemdispleased with the quality of the service provided by the bus companies operating in both cities. It is urgent the need to find possible practical alternatives to minimize the consequences of the main problems detected in this work. With these practical alternatives available, we will be able to offer to the Rio de Janeiro State authorities- suggestions about possible solutions to the main problems identified in this survey, as well as the time of implantation and costs of these solutions.
Abstract: This paper presents a threshold voltage model of pocket implanted sub-100 nm n-MOSFETs incorporating the drain and substrate bias effects using two linear pocket profiles. Two linear equations are used to simulate the pocket profiles along the channel at the surface from the source and drain edges towards the center of the n-MOSFET. Then the effective doping concentration is derived and is used in the threshold voltage equation that is obtained by solving the Poisson-s equation in the depletion region at the surface. Simulated threshold voltages for various gate lengths fit well with the experimental data already published in the literature. The simulated result is compared with the two other pocket profiles used to derive the threshold voltage models of n-MOSFETs. The comparison shows that the linear model has a simple compact form that can be utilized to study and characterize the pocket implanted advanced ULSI devices.
Abstract: Within dental-guided surgery, there has been a lack
of analytical methods for optimizing the treatment of the
rehabilitation concepts regarding geometrical variation. The purpose
of this study is to find the source of the greatest geometrical variation
contributor and sensitivity contributor with the help of virtual
variation simulation of a dental drill- and implant-guided surgery
process using a methodical approach. It is believed that lower
geometrical variation will lead to better patient security and higher
quality of dental drill- and implant-guided surgeries. It was found
that the origin of the greatest contributor to the most variation, and
hence where the foci should be set, in order to minimize geometrical
variation was in the assembly category (surgery). This was also the
category that was the most sensitive for geometrical variation.
Abstract: Magnesium alloy has been widely investigated as
biodegradable cardiovascular stent and bone implant. Its application
for biodegradable esophageal stenting remains unexplored. This
paper reports the biodegradation behaviors of AZ31 magnesium alloy
in artificial saliva and various types of beverage in vitro. Results
show that the magnesium ion release rate of AZ31 in artificial saliva
for a stent (2cm diameter, 10cm length at 50% stent surface
coverage) is 43 times lower than the daily allowance of human body
magnesium intakes. The degradation rates of AZ31 in different
beverages could also be significantly different. These results suggest
that the esophagus in nature is a less aggressive chemical
environment for degradation of magnesium alloys. The significant
difference in degradation rates of AZ31 in different beverages opens
new opportunities for development of degradation controllable
esophageal stent through customizing ingested beverages.
Abstract: Nowadays, cardiac disease is one of the most common
cause of death. Each year almost one million of angioplasty interventions and stents implantations are made all over the world.
Unfortunately, in 20-30% of cases neointimal proliferations leads to
restenosis occurring within the following period of 3-6 months. Three major factors are believed to contribute mostly to the edge
restenosis: (a) mechanical damage of the artery-s wall caused by the
stent implantation, (b) interaction between the stent and the blood constituents and (c) endothelial growth stimulation by small (lower
that 1.5 Pa) and oscillating wall shear stress. Assuming that this last actor is particularly important, a numerical model of restenosis
basing on wall shear stress distribution in the stented artery was elaborated. A numerical simulations of the development of in-stent
restenosis have been performed and realistic geometric patterns of a
progressing lumen reduction have been obtained
Abstract: The aim of this retrospective study was to evaluate the
parameters of dental implants such as patient gender, number of
implant, failed implant before prosthetic restorations and failed
implant after implantation and failed implant after prosthetic
restorations. 135 male and 99 female patients, total 234 implant
patients which have been treated with 450 implant between 2005-
2009 years in GATA Haydarpasa Training Hospital Dental Service.
Twelve implants were failed before prosthetic restorations. Four
implant were failed after fixed prosthetic restorations. Cumulative
survival rate after prostheses were 97.56 % during 6 years period.