Abstract: Kigelia africana (Lam.) Benth. (Bignoniaceae) is a
reputed traditional remedy for various human ailments such as skin
diseases, microbial infections, melanoma, stomach troubles,
metabolic disorders, malaria and general pains. In spite of the fruit
being widely used for purposes related to its antibacterial and
antifungal properties, the chemical constituents associated with the
activity have not been fully identified. To elucidate the active
principles, we evaluated the antimicrobial activity of fruit extracts
and purified fractions against Staphylococcus aureus, Enterococcus
faecalis, Moraxella catarrhalis, Escherichia coli, Candida albicans
and Candida tropicalis. Shade-dried fruits were powdered and
extracted with hydroalcoholic (1:1) mixture by soaking at room
temperature for 72 h. The crude extract was further fractionated by
column chromatography, with successive elution using hexane,
dichloromethane, ethyl acetate, acetone and methanol. The
dichloromethane and ethyl acetate fractions were combined and
subjected to column chromatography to furnish a wax and oil from
the eluates of 20% and 40% ethyl acetate in hexane, respectively. The
GC-MS and GC×GC-MS results revealed that linoleic acid, linolenic
acid, palmitic acid, arachidic acid and stearic acid were the major
constituents in both oil and wax. The crude hydroalcoholic extract
exhibited the strongest activity with MICs of 0.125-0.5 mg/mL,
followed by the ethyl acetate (MICs = 0.125-1.0 mg/mL),
dichloromethane (MICs = 0.250-2.0 mg/mL), hexane (MICs = 0.25-
2.0 mg/mL), acetone (MICs = 0.5-2.0 mg/mL) and methanol (MICs =
1.0-2.0 mg/mL), whereas the wax (MICs = 2.0-4.0 mg/mL) and oil
(MICs = 4.0-8.0 mg/mL) showed poor activity. The study concludes
that synergistic interactions of chemical constituents could be
responsible for the antimicrobial activity of K. africana fruits, which
needs a more holistic approach to understand the mechanism of its
antimicrobial activity.
Abstract: The asynchronous discussion forum is one of the most
widely used activities in learning management system environment.
Online forum allows participants to interact, construct knowledge,
and can be used to complement face to face sessions in blended
learning courses. However, to what extent do the students perceive
the benefits or advantages of forum remain to be seen. Through
content and social network analyses, instructors will be able to gauge
the students’ engagement and knowledge construction level. Thus,
this study aims to analyze the students’ level of knowledge
construction and their participation level that occur through online
discussion. It also attempts to investigate the relationship between the
level of knowledge construction and their social interaction patterns.
The sample involves 23 students undertaking a master course in one
public university in Malaysia. The asynchronous discussion forum
was conducted for three weeks as part of the course requirement. The
finding indicates that the level of knowledge construction is quite
low. Also, the density value of 0.11 indicating the overall
communication among the participants in the forum is low. This
study reveals that strong and significant correlations between SNA
measures (in-degree centrality, out-degree centrality) and level of
knowledge construction. Thus, allocating these active students in
different group aids the interactive discussion takes place. Finally,
based upon the findings, some recommendations to increase students’
level of knowledge construction and also for further research are
proposed.
Abstract: Recent concerns about the value of teaching cursive
handwriting in the classroom are based on the belief that cursive
handwriting or penmanship is an outdated and unnecessary skill in
today’s online world. The discussion of this issue begins with a
description of current initiatives to eliminate handwriting instruction
in schools. This is followed by a brief history of cursive writing
through the ages. Next considered is a description of its benefits as a
preliminary process for younger children as compared with
immediate instruction in keyboarding, particularly in the areas of
vision, cognition, motor skills and automatic fluency. Also
considered, is cursive’s companion, paper itself, and the impact of a
paperless, “screen and keyboard” environment. The discussion
concludes with a consideration of the unique contributions of cursive
and keyboarding as written forms of communication, along with their
respective surfaces, paper and screen. Finally, an assessment of the
practical utility of each skill is followed by an informal assessment of
what is lost and what remains as we move from a predominantly
paper and pen world of handwriting to texting and keyboarding in an
environment of screens.
Abstract: One- and two-dimensional carbon nanostructures with
sp2 hybridization of carbon atoms (single walled carbon nanotubes
and graphene) are promising materials in future electronic and
spintronics devices due to specific character of their electronic
structure. In this paper we present a comparative study of graphene
and single-wall carbon nanotubes by Raman spectro-microscopy in
strong magnetic field. This unique method allows to study changes in
electronic band structure of the two types of carbon nanostructures
induced by a strong magnetic field.
Abstract: Metal-enhanced Luminescence of silicon nanocrystals
(SiNCs) was determined using two different particle sizes of silver
nanoparticles (AgNPs). SiNCs have been characterized by scanning
electron microscopy (SEM), high resolution transmission electron
microscopy (HRTEM), Fourier transform infrared spectroscopy
(FTIR) and X-ray photoelectron spectroscopy (XPS). It is found that
the SiNCs are crystalline with an average diameter of 65 nm and FCC
lattice. AgNPs were synthesized using photochemical reduction of
AgNO3 with sodium dodecyl sulphate (SDS). The enhanced
luminescence of SiNCs by AgNPs was evaluated by confocal Raman
microspectroscopy. Enhancement up to x9 and x3 times were
observed for SiNCs that mixed with AgNPs which have an average
particle size of 100 nm and 30 nm, respectively. Silver NPs-enhanced
luminescence of SiNCs occurs as a result of the coupling between the
excitation laser light and the plasmon bands of AgNPs; thus this
intense field at AgNPs surface couples strongly to SiNCs.
Abstract: Ficus deltoidea from the Moraceae family is a popular
medicinal herb in Malaysia. It possesses strong antioxidant and antiinflammatory
properties. In the present study, the anti-inflammatory
effects of F. deltoidea extract on UVB-irradiated HaCaT
Keratinocytes were investigated. HaCaT Keratinocytes were UVBirradiated
(12.5 mJ/cm3) and were treated with 0.05, 0.08 or 0.1% of
F. deltoidea extract. Cell viability following UVB irradiation was
significantly higher in the groups treated with the F. deltoidea extract
at doses of 0.05, 0.08 or 0.1% than in control group with UVB
irradiation only. Tumor necrosis factor-α (TNF-α), interleukin-1α
(IL-1α), interleukin-6 (IL-6) and cyclooxygenase (COX-2) play
primary roles in the inflammation process upon UV irradiation and
are known to be stimulated by UVB irradiation. Treatment with the
F. deltoidea extract dramatically inhibited the UV-induced TNF-α,
IL-1α, IL-6, and COX-2 expression. These results suggest that the F.
deltoidea extract inhibits the production of pro-inflammatory
cytokines and may be an effective protective agent for the treatment
of skin diseases.
Abstract: In the 13th Malaysia’s General Elections held in 2013,
it was observed that large numbers of urban constituencies saw
strongly decisive young voters (between 21-39 age group) determine
the outcome in their favour. Also, the Elections Commission had
approximated that 70% of some 4.2 million unregistered voters at the
time were citizens aged between 21 and 40 years old. If they are not
already considered an important form of political leverage, 450,000
young Malaysians turn 21 years old each year. Further compounding
this fact were the 2.4 million new voters registered in 2012, which at
the time constituted almost 30% of the entire voting population. This
article discusses the importance of issues for the youth, with
reference to the university students in Malaysia in their decision
making on polling day.
Abstract: Malathion (ML) is a well known pesticide commonly
used in many agricultural and non-agricultural processes. Its toxicity
has been attributed primarily to the accumulation of acetylcholine
(Ach) at nerve junctions, due to the inhibition of acetylcholinesterase
(AChE). The aim of the current research was to study the protective
effect of the melissa plant extract against reproductive impairment
induced by malathion in 32 male albino rats, and the biological
experiment was divided into four groups (8 in each) that given
malathion (27 mg/kg; 1/50 of the LD50 for an oral dose) and/or
Melissa officinalis (MO) extract (200mg/kg/day) by gavages
technique. The sperm counts, sperm motility, sperm morphology,
FSH, LH, and testosterone levels had been determined in testes
homogenate at the end of the experiment. It is worthy to report that,
rats treated with melissa extract did not show a significant difference
when compared with the control group, while rats given malathion
alone had significantly lower sperm count, sperm motility, and
significantly higher abnormal sperm numbers, than the untreated
control rats as well as having significantly lower serum FSH, LH, and
testosterone levels compared with the control group. Administrations
of melissa extract restore all mentioned histological parameters
towards the control group and the melissa extract had a strong
positive protective effect against malathion toxicity. Results the of
biological parameters were confirmed by the histological
examination of rat testes and indicated that, both control and melissa
groups showing normal seminiferous tubules, while malathion group
testicular tissues had necrosis, edema in the seminiferous tubules and
degeneration of spermatogonial cells lining the seminiferous tubules
with incomplete spermatogenesis. The use of melissa against
malathion improved the histological picture and showing normal
seminiferous tubules with complete spermatogenesis and almost there
was no histopathological changes could be noted.
Abstract: Color Histogram is considered as the oldest method
used by CBIR systems for indexing images. In turn, the global
histograms do not include the spatial information; this is why the
other techniques coming later have attempted to encounter this
limitation by involving the segmentation task as a preprocessing step.
The weak segmentation is employed by the local histograms while
other methods as CCV (Color Coherent Vector) are based on strong
segmentation. The indexation based on local histograms consists of
splitting the image into N overlapping blocks or sub-regions, and
then the histogram of each block is computed. The dissimilarity
between two images is reduced, as consequence, to compute the
distance between the N local histograms of the both images resulting
then in N*N values; generally, the lowest value is taken into account
to rank images, that means that the lowest value is that which helps to
designate which sub-region utilized to index images of the collection
being asked. In this paper, we make under light the local histogram
indexation method in the hope to compare the results obtained against
those given by the global histogram. We address also another
noteworthy issue when Relying on local histograms namely which
value, among N*N values, to trust on when comparing images, in
other words, which sub-region among the N*N sub-regions on which
we base to index images. Based on the results achieved here, it seems
that relying on the local histograms, which needs to pose an extra
overhead on the system by involving another preprocessing step
naming segmentation, does not necessary mean that it produces better
results. In addition to that, we have proposed here some ideas to
select the local histogram on which we rely on to encode the image
rather than relying on the local histogram having lowest distance with
the query histograms.
Abstract: From an organizational perspective, leaders are a
variation of the same talent pool in that they all score a larger than
average value on the bell curve that maps leadership behaviors and
characteristics, namely competence, vision, communication,
confidence, cultural sensibility, stewardship, empowerment,
authenticity, reinforcement, and creativity. The question that remains
unanswered and essentially unresolved is how to explain the irony
that leaders are so much alike yet their organizations diverge so
noticeably in their ability to innovate. Leadership intersects with
innovation at the point where human interactions get exceedingly
complex and where certain paradoxical forces cohabit: conflict with
conciliation, sovereignty with interdependence, and imagination with
realism. Rather than accepting that leadership is without context, we
argue that leaders are specialists of their domain and that those
effective at leading for innovation are distinct within the broader pool
of leaders. Keeping in view the extensive literature on leadership and
innovation, we carried out a quantitative study with data collected
over a five-year period involving 240 participants from across five
dissimilar companies based in the United States. We found that while
innovation and leadership are, in general, strongly interrelated (r =
.89, p = 0.0), there are five qualities that set leaders apart on
innovation. These qualities include a large radius of trust, a restless
curiosity with a low need for acceptance, an honest sense of self and
other, a sense for knowledge and creativity as the yin and yang of
innovation, and an ability to use multiple senses in the engagement
with followers. When these particular behaviors and characteristics
are present in leaders, organizations out-innovate their rivals by a
margin of 29.3 per cent to gain an unassailable edge in a business
environment that is regularly disruptive. A strategic outcome of this
study is a psychometric scale named iLeadership, proposed with the
underlying evidence, limitations, and potential for leadership and
innovation in organizations.c
Abstract: Enzyme activity was evaluated in the intestine of
juvenile dourado (Salminus brasiliensis) fed with diets containing 0,
10 or 20% of lyophilized bovine colostrum (LBC) inclusion for either
30 or 60 days. The intestinal enzymes acid and alkaline phosphatase
(ACP and ALP, respectively), non-specific esterase (NSE), lipase
(LIP), dipeptidyl aminopeptidase IV (DAP IV) and leucine
aminopeptidase (LAP) were studied using histochemistry in four
intestinal segments (S1, S2, S3 and posterior intestine). Weak
proteolitic activity was observed in all intestinal segments for DAP
IV and LAP. The activity of NSE and LIP was also weak in all
intestines, except for the moderate activity of NSE in the S2 of 20%
LBC group after 30 days and in the S1 of 0% LBC group after 60
days. The ACP was detected only in the S2 and S3 of the 10% LBC
group after 30 days. Moderate and strong staining was observed in
the first three intestinal segments for ALP and weak activity in the
posterior intestine. The activity of DAP IV, LAP and ALP were also
present in the cytoplasm of the enterocytes. In the present results,
bovine colostrum feeding did not cause alterations in activity of
intestinal enzymes.
Abstract: Thermal insulation materials based on natural fibers
represent a very promising area of materials based on natural easy
renewable row sources. These materials may be in terms of the
properties of most competing synthetic insulations, but show
somewhat higher moisture sensitivity and thermal insulation
properties are strongly influenced by the density and orientation of
fibers. The paper described the problem of hygrothermal behavior of
thermal insulation materials based on natural plant and animal fibers.
This is especially the dependence of the thermal properties of these
materials on the type of fiber, bulk density, temperature, moisture and
the fiber orientation.
Abstract: Osteoporosis is a common multifactorial disease with
a strong genetic component characterized by reduced bone mass and
increased risk of fractures. Genetic factors play an important role in
the pathogenesis of osteoporosis. The aim of our study was to
identify the genotype and allele distribution of T245G polymorphism
in OPG gene in Slovak postmenopausal women. A total of 200
unrelated Slovak postmenopausal women with diagnosed
osteoporosis and 200 normal controls were genotyped for T245G
(rs3134069) polymorphism of OPG gene. Genotyping was performed
using the Custom Taqman®SNP Genotyping assays. Genotypes and
alleles frequencies showed no significant differences (p=0.5551;
p=0.6022). The results of the present study confirm the importance of
T245G polymorphism in OPG gene in the pathogenesis of
osteoporosis.
Abstract: Control of a semi-batch polymerization reactor using
an adaptive radial basis function (RBF) neural network method is
investigated in this paper. A neural network inverse model is used to
estimate the valve position of the reactor; this method can identify the
controlled system with the RBF neural network identifier. The
weights of the adaptive PID controller are timely adjusted based on
the identification of the plant and self-learning capability of RBFNN.
A PID controller is used in the feedback control to regulate the actual
temperature by compensating the neural network inverse model
output. Simulation results show that the proposed control has strong
adaptability, robustness and satisfactory control performance and the
nonlinear system is achieved.
Abstract: Multi-component data envelopment analysis (MC-DEA) is a popular technique for measuring aggregate performance of the decision making units (DMUs) along with their components. However, the conventional MC-DEA is limited to crisp input and output data which may not always be available in exact form. In real life problems, data may be imprecise or fuzzy. Therefore, in this paper, we propose (i) a fuzzy MC-DEA (FMC-DEA) model in which shared and undesirable fuzzy resources are incorporated, (ii) the proposed FMC-DEA model is transformed into a pair of crisp models using α cut approach, (iii) fuzzy aggregate performance of a DMU and fuzzy efficiencies of components are defined to be fuzzy numbers, and (iv) a numerical example is illustrated to validate the proposed approach.
Abstract: Compared with traditional distributed environment, the
net-centric environment brings on more demanding challenges for
information sharing with the characteristics of ultra-large scale and
strong distribution, dynamic, autonomy, heterogeneity, redundancy.
This paper realizes an information sharing model and a series of core
services, through which provides an open, flexible and scalable
information sharing platform.
Abstract: Virtual reality (VR) is a rapidly emerging computer
interface that attempts to immerse the user completely within an
experimental recreation; thereby, greatly enhancing the overall
impact and providing a much more intuitive link between the
computer and the human participants. The main objective of this
study is to design tractor trailer capable of meeting the customers’
requirements and suitable for rough conditions to be used in
combination with a farm tractor in India. The final concept is capable
of providing arrangements for attaching the trailer to the tractor easily
by pickup hitch, stronger and lighter supporting frame, option of
spare tyre etc. Furthermore, the resulting product design can be sent
via the Internet to customers for comments or marketing purposes.
The virtual prototyping (VP) system therefore facilitates advanced
product design and helps reduce product development time and cost
significantly.
Abstract: Photoacoustic imaging (PAI) is a non-invasive and
non-ionizing imaging modality that combines the absorption contrast
of light with ultrasound resolution. Laser is used to deposit optical
energy into a target (i.e., optical fluence). Consequently, the target
temperature rises, and then thermal expansion occurs that leads to
generating a PA signal. In general, most image reconstruction
algorithms for PAI assume uniform fluence within an imaging object.
However, it is known that optical fluence distribution within the
object is non-uniform. This could affect the reconstruction of PA
images. In this study, we have investigated the influence of optical
fluence distribution on PA back-propagation imaging using finite
element method. The uniform fluence was simulated as a triangular
waveform within the object of interest. The non-uniform fluence
distribution was estimated by solving light propagation within a
tissue model via Monte Carlo method. The results show that the PA
signal in the case of non-uniform fluence is wider than the uniform
case by 23%. The frequency spectrum of the PA signal due to the
non-uniform fluence has missed some high frequency components in
comparison to the uniform case. Consequently, the reconstructed
image with the non-uniform fluence exhibits a strong smoothing
effect.
Abstract: This paper presents a neural network based model predictive control (MPC) strategy to control a strongly exothermic reaction with complicated nonlinear kinetics given by Chylla-Haase polymerization reactor that requires a very precise temperature control to maintain product uniformity. In the benchmark scenario, the operation of the reactor must be guaranteed under various disturbing influences, e.g., changing ambient temperatures or impurity of the monomer. Such a process usually controlled by conventional cascade control, it provides a robust operation, but often lacks accuracy concerning the required strict temperature tolerances. The predictive control strategy based on the RBF neural model is applied to solve this problem to achieve set-point tracking of the reactor temperature against disturbances. The result shows that the RBF based model predictive control gives reliable result in the presence of some disturbances and keeps the reactor temperature within a tight tolerance range around the desired reaction temperature.
Abstract: This study presents the numerical simulation of three-dimensional incompressible steady and laminar fluid flow and conjugate heat transfer of a trapezoidal microchannel heat sink using water as a cooling fluid in a silicon substrate. Navier-Stokes equations with conjugate energy equation are discretized by finite-volume method. We perform numerical computations for a range of 50 ≦ Re ≦ 600, 0.05W ≦ P ≦ 0.8W, 20W/cm2 ≦q"≦ 40W/cm2. The present study demonstrates the numerical optimization of a trapezoidal microchannel heat sink design using the response surface methodology (RSM) and the genetic algorithm method (GA). The results show that the average Nusselt number increases with an increase in the Reynolds number or pumping power, and the thermal resistance decreases as the pumping power increases. The thermal resistance of a trapezoidal microchannel is minimized for a constant heat flux and constant pumping power.