Abstract: The purpose of this work is measurement of the
system presampling MTF of a variable resolution x-ray (VRX) CT
scanner. In this paper, we used the parameters of an actual VRX CT
scanner for simulation and study of effect of different focal spot sizes
on system presampling MTF by Monte Carlo method (GATE
simulation software). Focal spot size of 0.6 mm limited the spatial
resolution of the system to 5.5 cy/mm at incident angles of below 17º
for cell#1. By focal spot size of 0.3 mm the spatial resolution
increased up to 11 cy/mm and the limiting effect of focal spot size
appeared at incident angles of below 9º. The focal spot size of 0.3
mm could improve the spatial resolution to some extent but because
of magnification non-uniformity, there is a 10 cy/mm difference
between spatial resolution of cell#1 and cell#256. The focal spot size
of 0.1 mm acted as an ideal point source for this system. The spatial
resolution increased to more than 35 cy/mm and at all incident angles
the spatial resolution was a function of incident angle. By the way
focal spot size of 0.1 mm minimized the effect of magnification nonuniformity.
Abstract: Infrared focal plane arrays (IRFPA) sensors, due to
their high sensitivity, high frame frequency and simple structure, have
become the most prominently used detectors in military applications.
However, they suffer from a common problem called the fixed pattern
noise (FPN), which severely degrades image quality and limits the
infrared imaging applications. Therefore, it is necessary to perform
non-uniformity correction (NUC) on IR image. The algorithms of
non-uniformity correction are classified into two main categories, the
calibration-based and scene-based algorithms. There exist some
shortcomings in both algorithms, hence a novel non-uniformity
correction algorithm based on non-linear fit is proposed, which
combines the advantages of the two algorithms. Experimental results
show that the proposed algorithm acquires a good effect of NUC with
a lower non-uniformity ratio.
Abstract: The focal spot of a high intensity focused ultrasound
transducer is small. To heat a large target volume, multiple treatment spots are required. If the power of each treatment spot is fixed, it could
results in insufficient heating of initial spots and over-heating of later ones, which is caused by the thermal diffusion. Hence, to produce a
uniform heated volume, the delivered energy of each treatment spot
should be properly adjusted. In this study, we proposed an iterative, extrapolation technique to adjust the required ultrasound energy of
each treatment spot. Three different scanning pathways were used to evaluate the performance of this technique. Results indicate that by using the proposed technique, uniform heating volume could be obtained.
Abstract: As more people from non-technical backgrounds
are becoming directly involved with large-scale ontology
development, the focal point of ontology research has shifted
from the more theoretical ontology issues to problems
associated with the actual use of ontologies in real-world,
large-scale collaborative applications. Recently the National
Science Foundation funded a large collaborative ontology
development project for which a new formal ontology model,
the Ontology Abstract Machine (OAM), was developed to
satisfy some unique functional and data representation
requirements. This paper introduces the OAM model and the
related algorithms that enable maintenance of an ontology that
supports node-based user access. The successful software
implementation of the OAM model and its subsequent
acceptance by a large research community proves its validity
and its real-world application value.
Abstract: This study investigates a voltage-controllable liquid crystals lens with a Fresnel zone electrode. When applying a proper voltage on the liquid crystal cell, a Fresnel-zone-distributed electric field is induced to direct liquid crystals aligned in a concentric structure. Owing to the concentrically aligned liquid crystals, a Fresnel lens is formed. We probe the Fresnel liquid crystal lens using a polarized incident beam with a wavelength of 632.8 nm, finding that the diffraction efficiency depends on the applying voltage. A remarkable diffraction efficiency of ~39.5 % is measured at the voltage of 0.9V. Additionally, a dual focus lens is fabricated by attaching a plane-convex lens to the Fresnel liquid crystals cell. The Fresnel LC lens and the dual focus lens may be applied for DVD/CD pick-up head, confocal microscopy system, or electrically-controlling optical systems.
Abstract: Transcription factor p53 has a powerful tumor
suppressing function that is associated with many cancers. However,
p53 of the molecular weight was higher make the limitation across to
skin or cell membrane. Thymidine dinucleotide (pTT), an
oligonucleotide, can activate the p53 transcription factor. pTT is a
hydrophilic and negative charge oligonucleotide, which delivery in to
cell membrane need an appropriate carrier. The aim of this study was
to improve the bioavailability of the nucleotide fragment, thymidine
dinucleotide (pTT), using elasic liposome carriers to deliver the drug
into the skin. The study demonstrate that dioleoylphosphocholine
(DOPC) incorporated with sodium cholate at molar ratio 1:1 can
archived the particle size about 220 nm. This elastic liposome could
penetration through skin from stratum corneum to whole epidermis by
confocal laser scanning microscopy (CLSM). Moreover, we observed
the the slight increase in generation of p53 by western blot.
Abstract: Mechanical interaction between endothelial cells (ECs) and the extracellular matrix (or collagen gel) is known to influence the sprouting response of endothelial cells during angiogenesis. This influence is believed to impact on the capability of endothelial cells to sense soluble chemical cues. Quantitative analysis of endothelial-cell-mediated displacement of the collagen gel provides a means to explore this mechanical interaction. Existing analysis in this context is generally limited to 2D settings. In this paper, we investigate the mechanical interaction between endothelial cells and the extracellular matrix in terms of the endothelial-cellmediated displacement of the collagen gel in both 2D and 3D. Digital image correlation and Digital volume correlation are applied on confocal reflectance image stacks to analyze cell-mediated displacement of the gel. The skeleton of the sprout is extracted from phase contrast images and superimposed on the displacement field to further investigate the link between the development of the sprout and the displacement of the gel.
Abstract: Topical photodynamic therapy (PDT) with
5-aminolevulinic acid (ALA) is an alternative therapy for treating
superficial cancer, especially for skin or oral cancer. ALA, a precursor
of the photosensitizer protoporphyrin IX (PpIX), is present as
zwitterions and hydrophilic property which make the low permeability
through the cell membrane. Collagen is a traditional carrier; its
molecular composed various amino acids which bear positive charge
and negative charge. In order to utilize the ion-pairs with ALA and
collagen, the study employed various pH values adjusting the net
charge. The aim of this study was to compare a series collagen form,
including solution, gel and sponge to investigate the topical delivery
behavior of ALA. The in vivo confocal laser scanning microscopy
(CLSM) study demonstrated that PpIX generation ability was different
pattern after apply for 6 h. Gel type could generate high PpIX, and
archived more deep of skin depth.
Abstract: This study adopts a qualitative approach, which
engages in the dialectical discussion on two levels of dyad opposite
views. The first level of the dyad opposite views is the Western
strategic perspective and the Eastern Tai-Chi thinking. The second
level of the dyad opposite views is resource-based view and resource
dependence theory. This study concludes the resource-oriented actions
for competitive advantage as the metaphor of Tai-Chi consisted of yin
and yang. This study argues that the focal firm should adopt bridging
strategy during the core competence development period because its
core competence development is likely to meet its competitor’s needs
of exploring strategy during the competitor’s external resource
development stage. In addition, the focal firm should adopt buffering
strategy during the external resource development period to prevent its
competitor’s the exploiting strategy from attack during the
competitor’s core competence development stage. Consequently, this
study takes a significant first step toward a novel contextualize
understanding of resource development based on strategic perspective
and Tai-Chi thinking providing more fully sustainable strategy for
competitive advantage.
Abstract: Titanium alloys like the modern alloy Ti 6Al 2Sn 4Zr 6Mo (Ti-6246) combine excellent specific mechanical properties and corrosion resistance. On the other hand,due to their material characteristics, machining of these alloys is difficult to perform. The aim of the current study is the analyses of wear mechanisms of coated cemented carbide tools applied in orthogonal cutting experiments of Ti-6246 alloy. Round bars were machined with standard coated tools in dry conditions on a CNC latheusing a wide range of cutting speeds and cutting depths. Tool wear mechanisms were afterwards investigated by means of stereo microscopy, optical microscopy, confocal microscopy and scanning electron microscopy. Wear mechanisms included fracture of the tool tip (total failure) and abrasion. Specific wear features like crater wear, micro cracks and built-up edgeformation appeared depending of the mechanical and thermal conditions generated in the workpiece surface by the cutting action.
Abstract: Clinically, chickens showed progressively developed
clinical signs represented by sever cyanosis of the comb and wattles
with hemorrhage at the shanks, depression, and ruffling feathers with
loss of appetite and high daily mortalities. The ducks showed severe
neurological signs as torticollus, seizures and inability to stand with
mild signs of diarrhea and depression. Grossly, chickens showed
hemorrhages and congestion in most of the organs particularly lung,
liver, spleen, trachea and kidney. The examined ducks showed
multiple petechial hemorrhages, multifocal hemorrhagic necrosis in
the pancreas, pulmonary edema, congestion and hemorrhage in
meninges and congestion in the skeletal muscles. Histopathology
revealed severe congestion and hemorrhages in most of the organs
particularly lung, liver and kidney. Microscopic erosive tracheitis,
sever pulmonary congestion and perivascular oedema and lymphogranulocytic
pneumonia were constant. The liver showed hepatocyts
necrosis and lympho-granulocytic infiltration. The kidney showed
renal tubular necrosis and diffuse congestion. Multifocal, neuronal
necrosis, hemorrhages, multifocal glial nodules, lympho- histiocytic
perivascular cuffing, and occasional neuronophagia were observed in
the cerebrum. Other organs showed moderate changes.
Abstract: The paper presents a part of the results obtained in a
complex research project on Romanian Grey Steppe breed, owner of
some remarkable qualities such as hardiness, longevity, adaptability,
special resistance to ban weather and diseases and included in the
genetic fund (G.D. no. 822/2008.) from Romania.
Following the researches effectuated, we identified alleles of six
loci, codifying the six types of major milk proteins: alpha-casein S1
(α S1-cz); beta-casein (β-cz); kappa-casein (K-cz); beta-lactoglobulin
(β-lg); alpha-lactalbumin (α-la) and alpha-casein S2 (α S2-cz). In
system αS1-cz allele αs1-Cn B has the highest frequency (0.700), in
system β-cz allele β-Cn A2 ( 0.550 ), in system K-cz allele k-CnA2 (
0.583 ) and heterozygote genotype AB ( 0.416 ) and BB (0.375), in
system β-lg allele β-lgA1 has the highest frequency (0.542 ) and
heterozygote genotype AB ( 0.500 ), in system α-la there is
monomorphism for allele α-la B and similarly in system αS2-cz for
allele αs2-Cn A.
The milk analysis by the isoelectric focalization technique (I.E.F.)
allowed the identification of a new allele for locus αS1-casein, for two
of the individuals under analysis, namely allele called αS1-casein
IRV. When experiments were repeated, we noticed that this is not a
proteolysis band and it really was a new allele that has not been
registered in the specialized literature so far. We identified two
heterozygote individuals, carriers of this allele, namely: BIRV and
CIRV. This discovery is extremely important if focus is laid on the
national genetic patrimony.
Abstract: Recent trends in building constructions in Libya are
more toward tall (high-rise) building projects. As a consequence, a
better estimation of the lateral loading in the design process is
becoming the focal of a safe and cost effective building industry. Byin-
large, Libya is not considered a potential earthquake prone zone,
making wind is the dominant design lateral loads. Current design
practice in the country estimates wind speeds on a mere random
bases by considering certain factor of safety to the chosen wind
speed. Therefore, a need for a more accurate estimation of wind
speeds in Libya was the motivation behind this study. Records of
wind speed data were collected from 22 metrological stations in
Libya, and were statistically analysed. The analysis of more than four
decades of wind speed records suggests that the country can be
divided into four zones of distinct wind speeds. A computer “survey"
program was manipulated to draw design wind speeds contour map
for the state of Libya.
The paper presents the statistical analysis of Libya-s recorded
wind speed data and proposes design wind speed values for a 50-year
return period that covers the entire country.
Abstract: The purpose of this study is to present a non invasive
method for the marginal adaptation evaluation in class V composite
restorations. Standardized class V cavities, prepared in human
extracted teeth, were filled with Premise (Kerr) composite. The
specimens were thermo cycled. The interfaces were examined by
Optical Coherence Tomography method (OCT) combined with the
confocal microscopy and fluorescence. The optical configuration
uses two single mode directional couplers with a superluminiscent
diode as the source at 1300 nm. The scanning procedure is similar to
that used in any confocal microscope, where the fast scanning is enface
(line rate) and the depth scanning is much slower (at the frame
rate). Gaps at the interfaces as well as inside the composite resin
materials were identified. OCT has numerous advantages which
justify its use in vivo as well as in vitro in comparison with
conventional techniques.
Abstract: Bonding has become a routine procedure in several
dental specialties – from prosthodontics to conservative dentistry and
even orthodontics. In many of these fields it is important to be able to
investigate the bonded interfaces to assess their quality. All currently
employed investigative methods are invasive, meaning that samples
are destroyed in the testing procedure and cannot be used again. We
have investigated the interface between human enamel and bonded
ceramic brackets non-invasively, introducing a combination of new
investigative methods – optical coherence tomography (OCT),
fluorescence OCT and confocal microscopy (CM). Brackets were
conventionally bonded on conditioned buccal surfaces of teeth. The
bonding was assessed using these methods. Three dimensional
reconstructions of the detected material defects were developed using
manual and semi-automatic segmentation. The results clearly prove
that OCT, fluorescence OCT and CM are useful in orthodontic
bonding investigations.
Abstract: The objective of this work is to present a expertise on
flooding hazard analysis and how to reduce the risk. The analysis
concerns the disaster induced by the flood on November 10/11, 2001
in the Bab El Oued district of the city of Algiers.The study begins by
an expertise of damages in related with the urban environment and
the history of the urban growth of the site. After this phase, the work
is focalized on the identification of the existing correlations between
the development of the town and its vulnerability. The final step
consists to elaborate the interpretations on the interactions between
the urban growth, the sewerage network and the vulnerability of the
urban system.In conclusion, several recommendations are formulated
permitting the mitigation of the risk in the future. The principal
recommendations concern the new urban operations and the existing
urbanized sites.
Abstract: METIS is the Multi Element Telescope for Imaging
and Spectroscopy, a Coronagraph aboard the European Space
Agency-s Solar Orbiter Mission aimed at the observation of the solar
corona via both VIS and UV/EUV narrow-band imaging and spectroscopy. METIS, with its multi-wavelength capabilities, will
study in detail the physical processes responsible for the corona heating and the origin and properties of the slow and fast solar wind.
METIS electronics will collect and process scientific data thanks to its detectors proximity electronics, the digital front-end subsystem
electronics and the MPPU, the Main Power and Processing Unit,
hosting a space-qualified processor, memories and some rad-hard
FPGAs acting as digital controllers.This paper reports on the overall
METIS electronics architecture and data processing capabilities
conceived to address all the scientific issues as a trade-off solution between requirements and allocated resources, just before the
Preliminary Design Review as an ESA milestone in April 2012.
Abstract: This study determines the effect of naked and heparinbased
super-paramagnetic iron oxide nanoparticles on the human
cancer cell lines of A2780. Doxorubicin was used as the anticancer
drug, entrapped in the SPIO-NPs. This study aimed to decorate
nanoparticles with heparin, a molecular ligand for 'active' targeting
of cancerous cells and the application of modified-nanoparticles in
cancer treatment. The nanoparticles containing the anticancer drug
DOX were prepared by a solvent evaporation and emulsification
cross-linking method. The physicochemical properties of the
nanoparticles were characterized by various techniques, and uniform
nanoparticles with an average particle size of 110±15 nm with high
encapsulation efficiencies (EE) were obtained. Additionally, a
sustained release of DOX from the SPIO-NPs was successful.
Cytotoxicity tests showed that the SPIO-DOX-HP had higher cell
toxicity than the individual HP and confocal microscopy analysis
confirmed excellent cellular uptake efficiency. These results indicate
that HP based SPIO-NPs have potential uses as anticancer drug
carriers and also have an enhanced anticancer effect.