Film-makers in search
of Divya look-alike
v Page 28
Steroids can kill: Dark
side of body building
v Page 27
SQU team takes part in
Eco-Marathon Asia 2012
v Page 26
Hathaway’s pixie cut
left her in tears
v Page 28
Making a mark with
Northwest cuisine
v Page 27
Fea ures
Sunday, July 15, 2012
PMNs of neonatal
lambs and adults
P
olymorphonuclear leukocytes (PMNs)
serve as the first line of the immunological defence
of ruminants. However, despite the high morbidity and
mortality of neonatal lambs to a wide range of infections
there have been no definitive studies undertaken to
ascertain whether there might be functional differences
in PMN from neonatal lambs when compared to those
from adult sheep.
A pilot study at the College of Agricultural and Marine
Sciences has provided the first evidence that PMN from
neonatal lambs exhibit a significantly depressed intracel-
Solar energy is a renewable
source that can be utilised
effectively in many applications
in Oman such as: water heating,
cooling application (solar
refrigeration) and cooking
Students test new solar device
T
he demand for energy
is increasing all the time
and the environmental
and safety impacts of the use
of the conventional energy resources such as the oil and the
nuclear energy are huge and
unpredictable. The scientists
around the world are urged to
explore and find alternative
energy resources. A promising
alternative source of energy is
the solar energy which fits the
requirements of being environmentally clean and safe. Solar
energy has been the subject
of a study by an SQU team at
the Department of Mechanical and Industrial Engineering.
The aim is to investigate the
viability of using such energy
for cooking purposes.
Dr Mahmoud Tahat and
Dr Abdullah al Shabibi have
designed and tested a simple
solar oven under various conditions. As part of the testing
procedure,
thermo-couples
were used to measure the temperature at various places inside the cooking chamber. The
solar oven thermal efficiency
was calculated using the obtained experimental results.
Then, the cooker was tested
for real applications such as
boiling eggs and steaming
rice. The device proved to be
reliable, trouble-free and efficient. All kinds of food were
cooked, including meat, chicken, rice, peas, beans, potatoes,
soup, eggs and cakes. A good
meal for a family of four was
cooked in 3-4 hours. It was established that better heat transfer occurred when the cooking
pot was covered with an airtight plastic transparent cover
rather than using an ordinary
metallic cover.
The challenge: The researchers have said that the
demand as well as the unit cost
of conventional energy are
increasing every year, which
makes it imperative to look for
alternative sources of energy.
Solar energy is a renewable
source that can be utilised effectively in many applications
in Oman such as: water heating, cooling application (solar
refrigeration) and cooking.
Cooking accounts for a major
share of energy consumption
in developing countries. Most
of the cooking energy requirement is met by conventional
and non-conventional fuels
such as firewood, agricultural
waste and animal dung cake in
rural areas.
Oman has large deserts
and remote regions, where
Bedouins live without electricity and gas. A Bedouin living
in the remote places in the
desert depends largely on dung
(animals waste) and wood for
cooking. Usually the women
spend most of their time collecting wood and dung which
can be used for cooking. This
job can be risky for a lot of
women. Solar cooker can be
an excellent alternative to this
hard work and it can be used
very effectively in most parts
of Oman for cooking. Solar
energy is very abundant, clean
and environmentally friendly.
In addition, these deserts are
very hot in summer and the
ambient temperature can reach
up to a maximum of 47°C.
The climatic zone of the
Sultanate is dry and tropical,
characterised by extreme heat
in the summer around June
and coolness in the winter
around January. The Sultanate
receives a high degree of solar
radiation throughout the year.
Therefore, the researchers suggest that the country use solar
energy which is renewable and
readily available. Oman has
an average 9.49 hours of sunshine per day with a standard
deviation of 1.78 hours. The
average number of sunshine
hours ranges from 7.88 hours
in Salalah to 10.24 hours in
Buraimi. The solar radiation
averaged 18.71MJ/m2/a day
with standard deviation of 4
MJ/m2/day for Oman over the
period.
Theory of solar oven: The
basic principle of operation
of the hot box is based on the
principle of the greenhouse
effect, the academics explain.
As the direct and indirect short
wave radiation from the sun
pass through the hot box glass
cover, the short wave radiation will heat up the cooking
pot and collect the short wave
radiation heat absorbed partly
by the food, as a result of letting the sunlight pass through
a clear glass plate into a well-
insulated enclosure.
The light 'trapped' in the
box turns into heat when it is
absorbed by the black cooking
pot. The secret of a good solar box cooker is to have good
insulation with no air gaps and
a good lid reflector to get the
most light into the box.
The solar radiation energy
that is absorbed by dark pots
and the dark absorber plate underneath the pots is converted
into longer wavelength heat
energy and radiates from the
interior materials.
Most of this radiant energy
is of a longer wavelength and
cannot pass back out through
the glass and is therefore
trapped within the enclosed
space.
The reflected light is either
absorbed by other materials
within the space or, because
it doesn't change wavelength,
passes back out through the
glass. Critical to solar cooker
performance is the heat that
is collected by the dark metal
absorber plate and pots which
is conducted through those
materials to heat and cook the
food.
Experimental rig: The
hot solar box, made of wood,
was insulated from all sides
using glass wool in order to
minimise the heat loss to the
surroundings. The insulating
material was mounted to the
inner and outer box walls using glue and aluminium tape.
Aluminium and stainless steel
pots were painted black.
Thermo-couples were connected to a Multi-Point Data
Recorder to measure the ambient temperature, reflective
aluminium temperature, air
temperature inside the cooking
chamber and pot temperature.
The data was recorded every
10 minutes, over ten days, and
during the sunshine hours.
Observations: Temperature variations were observed
during the cooking tests. The
average ambient temperature
throughout the testing periods
was 40°C.
During the boiling test of
the eggs, which started at 9:50,
the eggs were well cooked at
11:40.
The maximum oven air
temperature achieved during
the test was 82.7°C at 10:50
and this value was maintained
until 12:10.
The maximum pot temperature reached was 103.9°C
at 12:40 pm. To investigate
the effect of using pots made
of different materials, two
tests were carried out to cook
0.2153 kg of rice with 0.3293
kg of water using stainless
steel and aluminium pots.
The test was conducted between 11:10 am and 2 pm. The
maximum stainless steel pot
temperature was 98°C after
150 minutes and the rice was
very well cooked after 130
minutes, whereas, the maximum temperature achieved by
the aluminium pot was 92°C
with the rice cooked after 150
minutes.
This shows that the stainless steel pot outperforms the
aluminium one.
The researchers concluded
their remarks by saying that
it would be feasible and economically viable to design and
construct hot box solar cooker
to be used in Oman, especially
in rural areas. The solar oven
is being examined by students
at SQU.
lular oxidative respiratory burst during the phagocytosis
of opsonised zymosan than their respective dams. This
observation was found to occur from the first week of life
and continuing for two months thereafter and is the first
published evidence that PMNs from neonatal lambs do
not phagocytise as efficiently as those from adult sheep.
Measurements were made using a chemiluminescence
(CL) assay optimised in the college’s lab.
As CL mirrors the ability of PMN to efficiently phagocytize and kill pathogens, these findings suggested that
PMN of neonatal lambs during the first two months are
less capable of defending them from pathogenic organisms.
Professor Eugene Johnson, at the Department of
Animal and Veterinary Sciences, SQU, has set plans to
expand on these preliminary findings. The ultrastructure
of PMNs of neonatal lambs will be compared with that
of adults and levels of stress hormones which might be
present at birth and potentially affect phagocytic function
are ascertained.
Flow cytometric analysis and CL assays will be conducted to determine if there are measurable differences
in PMN phagocytosis (oxygen independent) and both extracellular and intracellular respiratory burst activity. The
researcher hopes that, ultimately, some means to enhance
phagoctyic activity of PMN from newborns might be a
plausible therapeutic intervention.
Autism under scrutiny
A
n SQU researcher is investigating a connection
between autism, inflammation and energy
manipulation as a consequence of oxidative stress in the
deterioration that accompanied autism. Dr Mohammed
Issa Mustafa will also examine the roles of monoamine
oxidases and heat shock proteins in autism spectrum
disorders (ASD). It is hoped that the study could give a
lead to the finding of
novel biomarkers
for early detection
of autism in Oman.
Autism is a severe neurodevelopmental disorder
with onset prior to
three years of age.
Several
factors
have been implicated in the etiology of
autism, including genetic, environmental, autoimmune
and inflammatory factors. According to the Centres for
Disease Control and Prevention, prevalence of ASD in
USA, UK, Europe and Asia is one in 110 and the numbers
are increasing throughout the world, including Oman.
This will have enormous future public implications and
has stimulated intense research into potential etiologic
factors.
Dr Mustafa says that the identification of specific
biomarker correlates of autism might increase the reliability of the behavioural diagnosis of this disorder. Increasing evidence suggests the role of oxidative stress in
the development and clinical manifestation of autism. It
is suggested that autism may result from an interaction
between genetic, environmental, immunological factors
and localised inflammation of the central nervous system,
with oxidative stress as a mechanism linking these risk
factors.
The etiology of the autism is still unknown and no
reliable biomarkers have yet been identified as characteristic of ASD. Energy metabolism is usually manipulated in many neurodegenerative diseases and abnormal
monoamine oxidase A activity has been implicated in
autism and other neuropsychiatric disorders. Heat shock
protein antibodies have also been found in autism.