The Gist of Science Reporter: January + February 2013

The Gist of Science Reporter: January + February 2013











A Century of X-ray Diffraction

The discovery of X-ray diffraction was a central event in modern science. While
the technique of X-ray diffraction (XRD) began by identifying the symmetries in
the crystals of minerals, it eventually evolved into a unique and powerful
method of finding even the molecular structures in chemistry and biology. The
observation of X-ray diffraction by Friedrich, Knipping and Laue is one of the
most important discoveries in the history of science, and one with monumental
consequences, It opened the path for the development of modern solid-state
physics and materials science, including mineralogy, chemistry and molecular
biology. In fact, all the science describing the material world around us has
use for XRD and there is hardly any field in basic or applied research that has
not employed XRD for achieving its ends. It continues to widen its net even
Though the mysterious radiation discovered by Roentgen was named ‘X-ray’ the
debate was on for a few years whether they were waves or corpuscles (i.e.
particles). A wave is expected to provide diffraction. Roentgen worked hard to
get such an effect but could not.


When a wave hits an object, they cannot reach the region immediately behind that
object. Shadows are formed due to this. Since the waves of light are blocked,
the region immediately behind the object is darker.
But shadows are sharper close to an object than they are further from it. This
is due to diffraction. Waves that pass the object change their direction of
travel slightly. The wave that just missed the object spreads in a circle or
sphere. into the space behind the object. This is why shadows become more
blurred further away from the object that casts them. Eventually the spherically
spreading waves from each edge of the obstacle may even meet up.

Bragg Diffraction

To understand Braggs’ equation. let us look at an imaginary lattice array with
atoms as shown in the figure here. Let a narrow beam of monoenergetic X­-rays
fall on this array of atoms. Monoenergetic signifies that the beam has only one
wavelength e, unlike the experiments of Lane where the X-ray beam was a mixture
of rays of various wavelengths. This can be obtained by appropriate filters. For
X-rays, wavelength and energy are related; thus a single energy beam also means
a single wavelength beam.

Diffraction is a two-step process: first a scattering and then interference of
the scattered waves, either constructively or destructively. The single ray AO
hits an atom and gets scattered in the direction OB; the ray A’O’ goes in OW
direction. Notice the small cut marks on these waves which indicate location of
a crest of the wave; the distance between two consecutive marks is wavelength a
of the x-rays. The way marks placed on AO and A’O’ show that both the rays are
in phase – their crests occur at the same time along the journey. Scattered
waves OB and OW are also in phase. This is because the delay MO’ + O N is equal
to one or more integer multiple of a wavelength. So the phase of the scattered
ray is not disturbed and being at same phase OB and OW add the intensities on
the way ahead. That gives a dark spot on the X-ray film or a peak in intensity
of X-rays in a meter.

Applications in other Fields

This new and ingenious method of crystallography found favour with scientists in
other disciplines also. From the results of the work a realization was growing
about the connection between the structure of materials and their properties as
well as reactions. This was true for metallurgy and chemistry; somewhat later
biology also joined the pursuit.

Cellulose structure was seen in 1920. The first organic structure determined was
Hexamethylene Tetramine in 1923 (by Dickinson and Raymond). The nature of bonds
in molecules could be understood from diffraction studies. The Benzene structure
was understood in 1928 by Kathleen Lonsdale. C.G. Darwin (grandson of the famous
Charles Darwin) gave a method to determine valency from the crystal structure.
Later, a separate branch in chemistry called structural chemistry evolved.

Metallurgy has derived maximum benefits from the application of XRD. Alloys
could be better understood if the crystal structures were known. Graphical
representations of alloy compositions at different temperatures are called phase
diagrams; they are highly valuable tools to understand an alloy’s behavior.
These could be generated with the help from the XRD. The modern XRD units
facilitate dynamic study of structures by observing the changes in metallic
phases in real time with changing temperatures. Even creating new alloys of
desired properties is possible with the help of XRD and electron microscopes. If
the material or a component is under stress – applied or left over after
fabrication sequence – the lattice gets distorted. This results in a change in
parameter ‘d’ and can be detected easily by XRD. This is a popular application
of XRD in residual stress measurement in engineering.

Applications in Biology

Bioscientists were the last to get on board the XRD train. This is because XRD
and crystallography were synonymous in those days. No biological substance,
except bone, appeared to be crystalline, though later it came to be known that
the X-ray techniques could be used for amorphous materials also, But biologists
entered through a different route. They worked on crystallizing the proteins to
study them. J.D. Bernal in England was the first to get X-ray photos of proteins
in 1934, published in Nature (Vol. 133, p 794). Several biochemicals in our body
are actually proteins: enzymes, hormones, haemoglobin or antibodies.

They are large molecules and finding their structure was challenging. Sometimes
it took five to seven years after obtaining the X-ray pictures to determine the
exact structure in three dimensions.

After Bernal, his colleague Dorothy Crowfoot Hodgkin pursued this field of
biomolecules throughout her life, deciphering Cholesterol, Penicillin and
Vitamin B-12 etc. Her decoding of insulin came after she won the Nobel Prize in
1964. Credit for solving haemoglobin goes to John Kendrew and Max Perutz, whose
efforts were aided by improved instrumentation and evolved mathematics.

In this chain of workers came Rosalind Franklin at the King’s College London, as
well as James Watson and Francis Crick at Cavendish Lab at Cambridge. The latter
two gave the model of the hereditary material DNA (deoxyribonucleic acid). The
molecular model was built up based on X-ray photos taken by Rosalind and Maurice
Wilkins, though Watson and Crick did not acknowledge this fact till Rosalind was
alive. It is an old and lively debate in the history of science. It is really a
tribute to the long career of W.L. Bragg that he was the Head of Cavendish Lab
when this most important molecule was reconstructed using the technique he
invented 40 years earlier!!

The major impact of XRD work on human life has come through the achievements in
biological science more than any other branch of science. The functioning of
various proteins in the body depends on their shape; they connect to other
chemicals at the open ends of the molecule to give effect to many a biological
process. Thus, knowing their structure helps us to understand many processes and
enables intervention.

Take for instance drug design. Knowing the physiological basis of any ailment,
one can construct a drug that has a molecular structure of one’s choice to go
and nullify the malfunctioning molecule. Scientists at Squibb Institute of
Medical Research were the first to collaborate with crystallographers for drug
development, by targeting an enzyme for intentional latching. The first drug to
come out this way was Captopril in 1975, used to alleviate hypertension. A
branch of science called structural biology opened up to determine target
structures responsible for morbidity, including enzymes, protein receptors,
zones of DNA, RNA etc. These days, many drugs are designed in this way rather
than invented by an accident or iterative trials. This became feasible because
of better instrumentation for XRD technique, mathematical tools such as Fourier
analysis and, above all, the progress in computer technology that permitted
scientists to avail of the new theoretical concepts in a shorter time span.
While Vitamin B-12 (C63 H 88N14 014P Co) with 181 atoms took eight years to
resolve, today molecules comprising thousands of atoms can be resolved in a
matter of months, thanks to help from computers.

News Briefs

  • A team led by a physician-scientist and a chemist – from
    the fields of dermatology and nanotechnology – is the first to demonstrate
    the use of commercial moisturizers to deliver gene regulation technology
    that has great potential for life-saving therapies for skin cancers. Applied
    directly to the skin, the drug penetrates all of the skins layers and can
    selectively target disease­causing genes while sparing normal genes. Once in
    cells, the drug simply flips the switch of the troublesome genes to “off.”

  • Latest research has found that people who consume fast food
    even once a week increase their risk of dying from coronary heart disease by 20%
    in comparison to people who avoid fast food. For people eating_ fast food
    two-three times each week, the risk increases by 50% and the risk climbs to
    nearly 80% for people who consume last food items four or more times each week.
    A diet heavy in fast food increases the risk of developing Type­2 diabetes and
    coronary heart disease.

  • Signals from natural intestinal bacteria are necessary for an
    effective immune response to various viral or bacterial germs. Trillions of
    bacteria residing in the intestines of healthy humans contribute to digestion
    and metabolism of vitamins and are of critical importance for the host organism.
    Research has shown that the intestinal flora also plays an important role in the
    formation of the immune system in the intestines and that changes to it can
    increase the risk of food allergies or chronic inflammatory intestinal diseases.

  • The first images of an upward surge of the Sun’s gases into
    quiescent coronal-P loops have been identified by scientists. The discovery is
    one more step towards understanding the origins of extreme space storms. which
    can destroy satellite communications and damage power grids on Earth. The
    observation will help to understand how solar structures are heated and
    maintained in the upper solar atmosphere. Extreme solar activity can lead to
    severe space storms that interfere with satellite communications and damage
    electric power transmission grids on Earth.

  • Scientists foresee a time when medical monitoring devices
    would he integrated seamlessly into the huma body to track a patient’s vita
    signs and transmit them t/ his doctors. With current technology, electronics are
    able to stretch a small amount, but many potential applications require a device
    to stretch like a rubber band. Researchers at the McCormick School of
    Engineering have recently developed a design that allows electronics to bend and
    stretch to more than 200% their original size, four times greater than is
    possible with today’s technology. The key is a combination of a porous polymer
    and liquid metal.

  • Most people are fascinated by the colourful and exotic coral
    reefs but human civilization is the top danger to these fragile ecosystems
    through climate change, oxygen depletion and ocean acidification. Now scientists
    have investigated how and why the corals die when exposed to sedimentation.
    According to their findings, oxygen depletion, together with an acidification of
    the environment, creates a chain reaction that leads to coral death.

India’s First Indigenous AEW&C System Developed by Drdocabs

“The world is watching this programme with bated breadth. Its success will put
our country into the elite group that can develop and deliver such complex
state-of-the-art systems,” said Dr. Vijay Kumar Saraswat, Scientific Adviser to
the Raksha Mantri, Secretary Defence R&D and DG DRDO. He was speaking at a
function organized to commemorate the formal receipt of the Airbrone Early
Warning & Control (AEW&C) aircraft by Centre for Airborne System (CABS), the
DRDO laboratory spearheading the AEW&C programme. “The programme involves
installation of system on the aircraft, integration of these systems and make
the system perform to their fullest capability”.

Ozone Levels Around Delhi Prompt New Collaborative Research Project with India

Researchers from the University of Birmingham and TERI University are working
together to identify which emissions might best be controlled in order to
reduceharmful ozone production in New Delhi.

Ozone is a major air pollution problem in the Delhi area, where levels exceed
World Health Organisation guidelines for around 50 days per year. It leads to
significant reductions in regional crop yields and consequently has direct
economic impact. Ozone is also harmful to health, but as it is a secondary
pollutant the control of ozone levels is not straightforward. Understanding the
factors controlling ozone, and therefore identifying the optimum emissions
reductions to reduce ozone exposure, remains a key environmental challenge.

The Birmingham and TERI University researchers will deploy a newly developed
instrument to directly measure the local atmospheric ozone production rate in
Delhi. This will enable better understanding of the ozone production rate and
control regime. It will also begin to determine the extent to which local ozone
arises from local emissions at all – compared with, for example, ozone being
blown into the area from elsewhere. Both factors are critical for development of
local and regional policy measures to improve air quality.

Dr William Bloss, Reader in Atmospheric Science at the University of Birmingham,
said: “As Delhi grapples with air pollution, we feel this joint research project
with TERI University will provide critical insight into one aspect of the
problem, regional ozone production. While this project is limited to initially
exploring the potential to provide guidance for policy makers, it will provide
the proof-of-concept data necessary to justify future, larger-scale
measurements, which would have significant evidential weight for policy.”

Dr Nandini Kumar, Associate Professor at TERI University, added: “Ozone exposure
leads to significant reductions in crop yields across northern India, so
improved understanding of air pollution and the factors controlling ozone
formation in this region is really important. This project will help identify
which of thesefactors are emissions potentially within our control, to improve
future air quality.

Photosystem III for Efficient Photosynthesis

The develop biomass-based renewable and sustainable energy sources,
photosynthtic organisms, photosynthetic organisms need to be further researched
vis-a-vis increasing their photosynthsis efficiency. Photosynthetic organisms
like plant and algae have a well-develop solar energy harvesting system commonly
known as Photosystem I (PSI) and Photosystem II (PSII). However, these
photosystems have certain levels of limitation in trapping lilght energy because
of specificity in colour sensitivity, which is responsible for low
photosynthetic efficienty of these organisms.

Global Dimming: Contrasting Global Warming?

The Indian subcontinent witnessed about a month’s delayed arrival of monsoon in
2012. During the first decade of this twenty first century all the species of
this globe are suffering from extreme climatic impacts (heat wave, coldest
winter, drought, flood, water scarcity etc.). Scientists are explaining these
effects as a result of Global Warming caused due uncontrolled burning of fossil
fuels. But all the environmental phenomena cannot be explained only by Global
Warming. Some of these events can be accounted for by Global Dimming too. In
1985, an English scientist Gerald Stanhill working in the Agricultural Research
Organisation, Israel had noticed about 22% drop in sunlight in Israel compared
to that in 1950. This made Stanhill coin the term ‘Global Dimming’, which
contrasts interestingly with the term ‘Global Warming’.

The amount of average solar energy reaching the earth’s surface has been
observed to have dropped by more than 10% in the last six decades due to
blockage by suspended air particulate materials. The effect of Global Dimming
varies from place to place; for example, 9% in Antarctica, 10% in the USA, 16%
in parts of British Isles, 30% in Russia (formerly Soviet Union) and 37% in Hong
Kong from 1950 to 1990.

Solar radiation is measured in different weather stations throughout the globe
using units watt per square metre. Calculations by different groups of
scientists showed 7-14 watts per square metre (4-8%) drop in solar power from
1961 to 1990.

The reasons for Global Dimming are air pollution, particle-seeded water vapour
present in the cloud, contrails (vapour produced by aeroplanes), smog formation,
volcanic eruption, meteorite hitting etc. Clouds and suspended nanoparticles in
the air block a portion of solar energy before reaching the earth’s surface.

Scientists observed no heat reflection during the aftermath of the U.S. 9/11
attacks, when all the aeroplanes were grounded for three days. This suggests
that contrails are responsible for Global Dimming. Temperature rose by about one
degree Celsius during those three days. It is to be noted that the visible and
infrared radiations seem to be more affected than ultraviolet radiation.

Presence of excess air particulate materials due to pollution causes formation
of smaller number of water droplets resulting in reflecting back more sunlight
into space (since same amount of water is spread over more drops) and
simultaneously less rainfall (due to reduced coalescence of smaller droplets).

A 3% reduction of solar energy every year might cause complete darkness in about
330 years. Global Dimming is now being considered responsible for the droughts
in sub-Saharan Africa during the 1970s and 1980s. Darkness due to meteorite
impact on earth even caused the extinction of dinosaurs. Ripening of crops may
be affected in the cloudy areas and an equal percentage of drop in productivity
may take place with the percentage drop of solar radiation. Oceans get shielded
from getting full energy from sun and that might affect on the global rainfall

Global Dimming is a surface and near surface phenomena while Global Warming is
an entirely atmospheric phenomenon. Investigations reveal that the effect of
Global Dimming is half as large as that of Global Warming. In the year 2005, it
was reported by the Department of Applied Physics and Mathematics of Columbia
University, New York that the apparently opposing effects of Global Warming and
Global Dimming can occur simultaneously. One form of air pollution due to Green
House gases is responsible for Global Warming while another form of air
pollution due to air borne particles causes Global Dimming. Thus, Global Dimming
may be the effect of Global Warming and vice versa.

Biochemical Approaches Shed Insight of Receptor Biology

The Nobel Prize in Chemistry this year has gone to Dr. Robert Lefkowitz and Dr.
Brian Kobilka for studies of G-protein-coupled receptors. This selection of the
Nobel Committee is unusual in two respects. One, it is the first time that a
Chemistry prize has been awarded to two researchers who have trained as
physician-scientists (MD/PhD degree holders). Two, as it may have struck you, it
has been awarded to a research field in the biological sciences – a class of
cell surface receptors that have been studied extensively over the last forty

What explains this Nobel Prize selection? The interface between chemistry and
biology may be a very small part of any full biological process, but it advances
the understanding of these processes as well as therapeutic interventions aimed
at them. The research contributions of Lefkowitz and Kobilka have been
significantly aided by novel biochemical experimental approaches that did not
traditionally come from the biological sciences, but have revolutionized our
understanding of how a Ubiquitous class of biological receptors work. This
understanding has led to the development of many medicines aimed at G Protein
coupled receptors to cure ailments.
The G Protein coupled receptors (GPCR) are an important class of receptors, of
which there are 200 receptors whose function is well understood and 600
receptors whose function is yet to be understood. Many sensory, hormonal and
neuronal receptors belong to this category of receptors. G Protein coupled
receptors comprise of a protein chain that spans the cell membrane seven times,
and are connected to a ‘G Protein’. Various downstream cellular effects of
molecules binding to the cell’s surface derive from a contortion in the GPCR
when an external molecule binds to it, This contortion activates the G Protein,
orchestrating a sequential transfer of chemical messages and energy to obtain
specific intracellular effects in various cells, The Nobel Prize in Physiology
or Medicine 1994 was awarded to Alfred Gilman and Martin Rodbell for their
discovery of G Proteins and their role in signal transduction in cells.

Srinivasam Ramanujan

RAMANUJAN was born on 22 December 1887 to a poor family, at a place in Tamil
Nadu called Fu rte (In his maternal grandmother’s home), He was destined to be a
source of inspiration and a role model for many mathematicians who followed him,
According to Ramoseshan, ‘his life reads like a fairy tale, as melodramatic as a
bad Indian film’. His interest in mathematics became evident very early. As a
child, he was said to be curious about the distance and shape of stars and
calculated the length of equator all by himself. There is no record of how he
did this. When Pamanujan was a year and a half old, his mother gave birth to a
son named Sadagopan, who died less than three months later. In December 1889,
Ramanujan had smallpox and recovered, unlike thousands in the Thanjavur District
who died from the disease that year. He moved with his mother to her parents’
house in Kanchipuram, near Madras (now Chennai). In November 1891, and again in
1894, his mother gave birth to two children, but both children died in infancy.
Some of Ramanujan’s class mates and close relatives made some curious
observation about how the young boy set about making simple discoveries in
mathematics even at a tender age. It is said that he was often seen lying on his
stomach on a mat with a pillow under his chest, writing on a slate (a writing
pad which acted like a scratch pad memory for poor students). He had a peculiar
mannerism of rubbing out his calculations with his elbow. He was often seen
smiling and shaking his head. He would talk to himself, and if convinced that he
had made some discovery, would enter his results into a notebook. Thus, even at
a tender age, he recognized the importance of his discovery and the need to
preserve them. He was also very friendly and gregarious, ever punning on Thamizh
and English words. P.C. Mahalanobis, the well-known statistician who established
the Indian Statistical Institute in Calcutta, shared his room with Ramanujan
while they were in London. He one day shared a problem with Ramanujan (about ‘n’
houses in a row with natural numbers) and remarked that he was finding it
difficult to arrive at a solution. Ramanujan immediately gave the solution in a
totally unconventional way – in terms of continued fractions! When asked how he
arrived at the solution, he answered- “It is simple. The minute I heard the
problem, I knew that the answer was a continued fraction. Which continued
fraction, I asked myself. Then the answer come to my mind.”

Ramanujan’s Attempted Suicide

It is now a confirmed fact that in a fit of depression (we will come to the
reason later), Ramanujan attempted to commit suicide by throwing himself on the
railroad track of a London underground station. But by a ‘series of miracles’,
like the switch being turned off by a guardsman and the train coming to a stop
just a few feet away from him, he was saved. Ramanujan sustained only
superficial injuries in his legs. But since attempted suicide was a criminal
offence, the Scotland Yard promptly arrested him. Ramanujan called Hardy for
help and through a series of manipulations, Hardy bailed him out.

The story on Ramanujan’s attempted suicide became known in India when Chandra
mentioned it in a lecture in Delhi. Chandra had to face a lot of public wrath
including much rebuke from his paternal uncle, Sir C.V. Roman. Roman accused
Chandra of defaming Ramanujan by publicly narrating this episode which was
closely guarded by Hardy. On his part Chandra declared that there was nothing so
bad about the incident, except that t illustrated that even intellectuals like
Ramanujan can go through bouts of depression.

Methods of Algaculture

Ways of culturing algae range from closely controlled methods on the laboratory
bench top with a few litres of algae to less predictable methods in outdoor
tanks, containing thousand litres in which production relies on natural
conditions. The rate of growth and division varies with different types of algae
and also depends on how well the various culture conditions necessary for growth
have been met, There are three types of culture methods generally followed;

1. Batch Culture: A batch culture is used for small volumes of cultivation
space, usually upto ten litres. It is a system where the total culture is
harvested and used as a food.
2. Semi-Continuous culture: A semi­continuous culture is a system where part of
the culture is harvested and used as food and the amount taken is replaced with
fresh culture medium. After allowing 2-3 days for the remaining cells to grow
and divide, the process is repeated. Semi­continuous cultures may be operated
for 7 to 8 weeks.
3. Continuous Culture; A continuous culture is more long term, and is maintained
by monitoring and keeping some factor constant, In a turbidostat continuous
culture, the number of algal cells in the culture is monitored. As the cells
divide and grow, an automatic system keeps the culture density at a pre-set
level diluting the culture with fresh medium. In a chemostat continuous culture,
a flow of fresh medium is introduced into the culture at a steady predetermined

Environments for Algaculture Cultivation of Algae in Open Ponds

Open ponds can be categorized into natural waters (lakes, lagoons, ponds) and
artifical ponds or containers. The most commonly used systems include shallow
big ponds, tanks, circular ponds and raceway ponds. The ponds in which the algae
are cultivated are usually what are called the “raceway ponds”, as the algae,
water and nutrients circulate around a racetrack in these ponds. With
paddlewheels providing the flow, algae are kept supended in the water, and are
circulated back to the surface on a regular frequenc. The ponds are usually kept
shallow because the algae need to be exposed to sunlight, and sunlight can only
penetrate the pond water to a limited depth. The ponds are operated in a
continuous manner, with carbon dioxide and nutrients being constantly fed to the
ponds, while algae-containing water is removed at the other end, The biggest
advantage of these open ponds is their simplicity, easy construction (especially
compared to closed systems), low production and operating costs.

Cultivation of Algae in Closed Ponds

As a variation of the open pond system, the idea behind the closed pond is to
close it off, to cover a pond or pool with a greenhouse, While this usually
results in a smaller system, it does take care of many of the problems
associated with an open system particularly better control over the environment,
Closed Pond systems cost more than the open ponds, and considerably less than
photo bioreactors for similar areas of operation,
It allows more species to be grown, allows the species that are being grown to
stay dominant, and extends the growing season, only slightly if unheated, and if
heated it can produce year round, It is also possible to increase the amount of
carbon dioxide in these quasi-closed systems, thus again increasing the rate of
growth of algae, Closed ponds are used in Spirulina cultivation,

Cultivation of Algae in Photobioreactor

A photobioreactor is a closed equipment that provides a controlled environment
and enables high productivity of algae, As it is a closed system, all growth
requirements of algae are introduced into the system and controlled according to
the requirements, Photobioreactors facilitate better control of culture
environment such as carbon dioxide, water supply, optimal temperature, efficient
exposure to light, culture density, pH levels, gas supply rate, mixing regime,

Cultivation of Algae in Desert

Algae can be grown cheaply in saltwater ponds in the desert or even more
efficiently in proprietary photobloreoctors. It is conceivable that the
photobioreactors could be placed in a desert environment, although one of the
challenges for growing algae is to keep the water at a very consistent
temperature of around 70 degrees Fahrenheit so that it will likely also
influence optimal placement of the photoblorecctors. Growing algae is best
accomplished closer to the desert, where seasonal sunlight levels and
temperatures don’t vary as much as they do further away from the equator.
Another possible strategy to maintain temperature is to put the photobioreactors
near a conventional coal-burning electric plant and harvest the significant
amounts of carbon dioxide generated by the plant. Attractive as this sounds, the
production of biodiesel should not depend on a coal plant operating
indefinitely, Algae strains suitable for desert cultivation include,
Haematococcus pluvialis Microco/eus vaginatus, Chlamydomonas perigranulata and

Cultivation of Algae in Sewage and Wastewater Treatment Plant

Using algae for wastewater treatment offers some interesting advantages over
conventional wastewater treatment including cost effective treatment; low energy
requirement; reduction in sludge formation and production of algal biomass,
Algae can be used to treat both municipal and industrial wastewater, Algae play
a major role in aerobic treatment of waste in the secondary treatment process,
Algae-based municipal wastewater treatment systems are mainly used for nutrient
removal (removal of nitrogen and phosphorous), Algae have the ability to
accumulate the heavy metals and thereby remove toxic compounds from the
wastewater, In some cases, algae also play a role in the removal of pathogens in
the tertiary treatment stage.

Cultivation of Algae in Marine Environment

Salt water is more economical than fresh water for growing algae as the main
nutrients needed for algal growth are already present in seawater. Macro-algae
are cultivated at sea mainly by tying them to anchored floating lines, Seaweeds
do not require soil, and are already provided with all the water they need,
which is a major advantage over land production of biofuels since water is the
most limiting factor for most agricultural expansion [especially with climate
change), Aquaculture systems based jointly on microalgae and their animal
consumers, which can be considered as an indirect use of microalgae in human
food, have so far been much more successful. The uptake of microalgal biomass by
commercially important filter feeders is very promising from the energetic
standpoint. Microalgae are indeed the biological starting point for energy flow
through most aquatic ecosystems and as such are the basis of the food chain in
many aquaculture operations. Flocculation is an essential step in the
concentration and harvesting of microalgae from aquatic media. Salinity of
brackish water and seawater requires high flocculant dosages and renders
flocculation less effective than in freshwater algal media.

Glass Translator

This gadget translator has a video recorder, memory card, and can save all the
data inside the glass translator. It can translate all [tit languages.
Conversation is with the press of a button, record it and send to a remote
server where it is analyzed and translated. The server then sends the
translation to the receiving users who can read the word in their own language
on the display unit. With this gadget you don’t have to think about having to
translate your own words.

Digital Protractor

Do you have a great love for mathematics, and have an extreme partiality to
measuring angles? Well, no longer do you need to make a guess for an angle ever
again. This nifty little device is said to be able to measure angles with more
accuracy compared to the plastic, clear half circle that one would normally use.
The stainless steel rulers are extremely durable and can lock at any angle, and
professionals need not worry about it breaking. Those at school, too, are able
to make use of the Digital Protractor for their work. In addition, the Digital
Protractor works miracles as it can lock down at any angle you require, allowing
you to draw lines at the exact angle of your choice.

E-Ball Concept Pc

The E-Ball concept PC is a sphere-shaped computer, which is the smallest design
among all the laptops and desktops. This computer has all the features like
keyboard, mouse, DVD recorder, large screen display etc. E-Ball PC is placed on
two stands, opened by pressing and holding the two buttons located on each side
of the E-Ball PC. This pc is the latest concept technology. It has a laser
keyboard that is visible when the PC is working and also has an optical wireless
mouse that works very smoothly in any direction. E-Ball concept PC doesn’t have
any external display unit.

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