Water Pollution

Water is one of the most important natural resources for all living organisms. It is essential for the survival of any form of life in the biosphere. Water covers about three-fourths (75%) of the earth’s surface. But freshwater constitutes only about 1.998% of the earth’s total water supply. The quality of water is of vital concern for mankind, since it is directly linked with human welfare. Water pollution disturbs the normal uses of water for irrigation, agriculture, industries, public water supply and aquatic life. The word pollution is derived from the Latin word ‘pollutionem’ meaning ‘to make dirty’. Pollution is an undesirable change in the physical, chemical and biological characteristics of the environment. Water pollution is the deterioration in physical, chemical and biological properties of water brought about mainly by human activities and natural sources.

Types of water pollution

·         Surface water  pollution - pollution of lakes, rivers and oceans

·         Groundwater pollution - pollution of aquifers below soil.

·         Microbial   pollution – pollution by bacteria, viruses, protozoa and parasitic worms.

·         Oxygen depletion pollution – pollution by biodegradable organics.

·         Nutrient pollution – pollution by plant nutrients (nitrates, phosphates)

·         Suspended matter pollution – pollution by soil, silt

·         Chemical pollution -  pollution by pesticides, fertilizers, industrial solvents, oil

·         Thermal pollution- pollution by warm water, waste heat

Sources of water pollutants

Point Sources
A single definable source of the pollution, e.g. a factory, a sewage plant, etc.- pollution is easy to monitor and control.

Non-point sources 
No one single source, but a wide range of sources, e.g. runoff from urban areas, or farmland. Pollution is more difficult to monitor and control.

Non-persistent (degradable) water pollutants

Some wastes can be broken down by natural chemical reactions or by natural bacteria into simple, non-polluting substances such as carbon dioxide and nitrogen. e.g. wood, paper, biological wastes. More pollution load can lead to low oxygen levels and eutrophication.This damage is reversible.

Persistent Water pollutants

This is the most rapidly growing type of pollution. Organic chemical  substances that degrade very slowly or cannot be broken down at all; They  may remain in the aquatic environment for  longer periods of time. The damage  is  irreversible.

·         Pesticides - DDT, dieldrin

·         Leachate components from landfill sites (municipal, industrial)

·         Petroleum  and petroleum products

·         PCBs, dioxins, polycyclic aromatic hydrocarbons (PAHs)

·         Radioactive  materials- strontium-90, cesium-137, radium-226, and uranium

·         Metals  - lead, mercury, cadmium

kinds of  Water pollutants

·         Pathogens - bacteria, viruses, parasites.

·         Oxygen demanding wastes – animal manure, human wastes, plant residues.

·         Water soluble inorganic chemicals- acids, salts, toxic metal compounds like mercury and lead.

·         Inorganic plant nutrients – water soluble phosphates, nitrates, ammonium.

·         Organic chemicals - petrochemicals, plastics, pesticides, cleaning  solvents, detergents and industrial wastes. 

·         Sediment & Suspended Matter – dirt, soil, silt . –reduce water clarity.

·         Radioactive materials- uranium, thorium,  iodine and radon.

·         Thermal Water – heat From power plants, industrial cooling.

·         Alien Species - Zebra Mussels, Asiatic Catfish, Sea Lamprey, etc. 

Impact of  Microbial water pollution

The number of people lack access to safe drinking water is over 1 billion. The number of people lack adequate sanitation is 2.6 billion . This has led to widespread microbial contamination of drinking water. Deaths due to water-associated infectious diseases may go up to 3.2 million people per year. (approx. 6% of all deaths globally). Deaths due to diseases caused by inadequate water, sanitation, and hygiene are 1.8 million people.

Eutrophication (nutrient pollution)

Excessive amounts of plant nutrients like P,N,C cause excessive growth or ‘blooms of algae’. Algal blooms leads to oxygen depletion. Hypoxia leads to mass fish kills, degradation of water and habitat quality.

Oceans - A global dumping ground  

Around 50% of the world’s population lives on or within 160 miles of shore. Fourteen billion pounds of garbage, mostly plastic, is dumped into the ocean every year. For every 1 million tons of oil that is shipped, about 1 ton is spilled. More oil is seeped into the ocean each year as a result of leaking cars and other non-point sources.

River pollution

Asian rivers are the most polluted in the world. River Ganges in India is one of the most polluted rivers in the world. Approximately 46% of the lakes in America are too polluted for fishing, aquatic life, or swimming.

      Plastic waste in water

The amount of plastic waste has been increasing about 10% each year for the past 20 years. Over 1 million seabirds are killed by plastic waste per year. Over 100,000 sea mammals and countless fish are killed per year due to pollution.

Health impacts of dissolved chemicals in water

·         Pesticides  - damage nervous system and also cause cancer.

·         Lead – affects central nervous system .

·         Fluorides – damage teeth and the skeleton.

·         Nitrates – cause blue – baby syndrome in infants.

·         Petrochemicals – cause cancer.

·         Arsenic – damage liver and nervous system, skin cancer.

·         Heavy metals – damage nervous system and kidneys.

Air Pollution

The quality of human life is directly related to the quality of the environment. Air pollution is a major environmental health problem affecting everyone. Air pollution is defined as the unwanted introduction of particulates, gases and aerosols into the lower atmosphere. Air pollution is generally most widespread and some air pollutants are poisonous. Air pollution increases the risk of respiratory and heart disease in the population.

Sources of air pollution

Natural sources - volcanoes, fumaroles and hot springs, decay from marshes, bogs

Stationary sources - those that are fixed in location.

Point sources -e.g. smoke stacks, 14% air pollution from plants generating electricity;

Fugitive sources -e.g. construction sites, exposed areas;

Area sources- e.g. dense urban community or agricultural area

Mobile sources - those that move while polluting, e.g. trucks, cars, buses etc. 60% of air pollution from motor vehicles. 80-88% in major cities.

Kinds of air pollutants

Primary pollutants  - Pollutants that are emitted directly from identifiable sources –produced by both natural events or human activities e.g. sulfur dioxide (SO2), carbon monoxide (CO), nitric oxide (NO), nitrogen dioxide (NO2)

Secondary Pollutants: those that form as a result of a chemical reaction of the primary pollutant with a natural component of the environment.; e.g. some ozone, sulfuric and nitric acids.

Air pollution reduces visual range and atmospheric clarity, less contrast, less visibility. Air pollutants  damage  vegetation, including leaves, needles, fruit, growth rate, reproduction, hardiness. Air pollution  is responsible for decline in net primary productivity NPP. There is degradation of human health, from mild problems e.g. eye irritation, to severe e.g. respiratory disease asthma, bronchitis, emphysema, cancer. CO, carbon monoxide combines with hemoglobin and reduces bloods ability to carry oxygen. 150,000-350,000 deaths/yr.  Air pollution degrades  animal health with impacts on respiration, bones, teeth, reproduction; increase lake acidity, decline in NPP. When air pollutants settle, they cause  degradation of soil and water. Air pollution cause deterioration of man-made structures, break down car paint, roofing; acid rain chemically dissolves marble statues and other building materials

Human –induced greenhouse effect and global warming

Greenhouse gases  (GHGs)
Some greenhouse gases occur naturally in the atmosphere, while others result from human activities. Naturally occuring greenhouse gases include water vapor, carbon dioxide, methane, nitrous oxide, and ozone. Carbon dioxide is a product of burning fossil fuels and wood. Nitrous oxide (NO2), produced by fertilizer use and released from decomposition of animal wastes. Methane (CH4) is produced by bacteria from sediments, swamps, and in flooded rice paddies.Chlorofluorocarbons (CFCs), Freon (a refrigerant) deplete the ozone layer in the upper atmosphere. Halons, such as halocarbons), are released from fire extinguishers. Water vapor in clouds reradiate heat back to Earth.
Carbon dioxide and other gases allow light to pass, but trap heat in the atmosphere much like glass in a greenhouse traps heat. This greenhouse effect is thought to be responsible for global warming. Carbon dioxide contributes to only 56% of greenhouse heating. The average surface temperature of Earth is about 15°C (59°F). Global Warming is increase in the average temperature of the atmosphere, oceans, and landmasses of Earth. Global temperatures may increase by 3oC-4oC by the end of the next century .

Impact of Global warming

n  Temperature extremes 

n  Rise in sea level, and change in precipitation

n  Injuries from storms, coastal flooding 

n  Interruption of power supply, contamination of drinking water 

n  Drought 

n  Food shortages due to shift in agricultural food production 

n  Air pollution ( made worse by warming) 

n  Asthma, bronchitis, emphysema complications 

n  Strain on public health systems 

n  Increased need due to population migrations 

n  Unable to contain spread of infectious diseases 

The Ozone Layer

Earth's atmosphere consists of a number of different layers. The troposphere is the lower atmospheric layer. The stratosphere is often referred to as the upper atmosphere. The stratosphere contains the ozone shield, a layer of ozone (O3) in the stratosphere, 50 km above the ground. Ozone (Greek ozein, “to smell”), pale blue, highly poisonous gas with a strong odor. Ozone is considered a pollutant at ground level. Breathing O3 affects both the respiratory and nervous systems, resulting in respiratory distress, headache, and exhaustion. Ozone is damaging to plants, resulting in leaf mottling and reduced growth.

Health effects of Ozone depletion

Each 1% drop in ozone is thought to increase human skin cancer rates by 4-6%. The United Nations Environment Program predicts a 26 percent rise in cataracts and non-melanoma skin cancers for every 10% drop in ozone. This translates to 1.75 million cases of cataracts and 300,000 more cases of skin cancer every year.

Ozone Hole  above Antarctica

During the 1980s scientists discovered a "hole" in the ozone over Antarctica. The Antarctic ozone hole is an area of the Antarctic stratosphere in which the recent ozone levels have dropped to as low as 33% of their pre-1975 values. By the 1990s atmospheric scientists had detected an annual loss of 40-50% of the ozone above Antarctica, which produced an ozone hole every spring. One CFC molecule can destroy 100,000 ozone molecules.

Acid precipitation  (acid rain)

The term "acid rain" is commonly used to mean the deposition of acidic components in rain, snow, fog, dew, or dry particles. The more accurate term is "acid precipitation.“ "Clean" or unpolluted rain is slightly acidic, its pH being about 5.6, because carbon dioxide and water in the air react together to form carbonic acid, a weak acid.

H₂O  + CO₂  → H₂CO₃ (aq)

The extra acidity in rain comes from the reaction of primary air pollutants, primarily sulfur oxides and nitrogen oxides, with water in the air to form strong acids (like sulfuric and nitric acid). The main sources of these pollutants are vehicles and industrial and power-generating plants. Nitric oxide & sulfur dioxide released primarily from electric power plants & motor vehicles

SO₂ + water vapor + ozone ---> H₂SO₄

NO + sunlight + O₂ ---> NO₂ + various atmospheric gases ---> HNO₃

Environmental Impact of Acid deposition

n  Sterilization of lakes and forests.

n  Reducing the populations of small invertebrates and decomposers.

n  Reducing agricultural yields.

n  Causing extensive structural damage by corroding marble, metal, and stonework.

n  Degrading water supplies by leaching heavy metals from the soil into drinking-water supplies.

n  Increases in lung cancer and colon cancer.

Biotechnology of cloning

Cloning is the creation of an exact genetic replica of a small segment of DNA, a cell or a whole organism.Cloning is a form of asexual reproduction which is widespread in nature. In single cell organisms and plants, it is an entirely normal process (division, vegetative reproduction),Animals can be cloned by embryo splitting or nuclear transfer. Embryo splitting involves bisecting the multicellular embryo at an early stage of development to generate "twins". This type of cloning occurs naturally and has also been performed in the laboratory with a number of animal species.

Types of cloning

Natural cloning - Identical twins and multiple births are an example of human clones that are created naturally.
Artificial cloning - is created artificially in a laboratory Dolly, the cloned sheep produced in Scotland in 1997 (Nature, 385, 810- 13).

DNA cloning - is also known as recombinant DNA cloning , molecular cloning and gene cloning. DNA cloning refers to the process by which a fragment of DNA is transferred from one organism to a self-replicating genetic element such as a bacterial plasmid or a virus. Plasmids are self-replicating extra-chromosomal circular DNA molecules and can be used to make many copies of the gene. These genetic elements can then be inserted into a host cell of interest and the function of the gene of interest studied. Gene cloning is also important for the development of drugs and treatments such as in pharmacogenetics and gene therapy.

Reproductive cloning - is also called adult DNA cloning. The purpose is to produce a genetic duplicate of an existing or previously existing organism. Reproductive cloning refers to the process by which an animal is created which had the same nuclear DNA as a previously existing animal. This is accomplished by the removal of the DNA containing nucleus of an egg and its replacement by the DNA from another cell. The egg is then stimulated to divide and following a number of divisions it can be transferred into the uterus of a suitable female host until its birth.
Therapeutic cloning, or embryo cloning refers to the production of human embryos for research purposes. The goal of this is not to create cloned babies but to harvest the stem cells of the embryo that have the potential to develop into almost any cell in the body

Artificial cloning procedures

Embryo splitting – the blastomeres must be totipotent at 8-16 cell stage. The cell mass is cut with a glass knife dividing groups of blastomeres. One set of cells put into denuded zona pellucid. Identical twins result from embryo splitting. Embryo splitting changes neither the age nor the (toti-)potency of the cells used. The (two) embryos from the splitting are in the same stage of development, exactly the same age as the undivided embryo would have been and genetically completely identical.

Technique of Nuclear transfer technology

The nucleus transfer technique is the transfer of the genetic program (the cell nucleus with the desired genetic material) from a totipotent blastomere to an unfertilised egg cell whose nucleus has previously been removed. This technique basically offers the possibility of replicating an adult individual and their genetic program.
First, the donor cells are grown under special conditions in culture. The number of cells can be increased by several orders of magnitude. It is also possible to make genetic modifications and to select just those cells in which the desired modification has occurred and multiply these up. These cells are then fused with an unfertilised egg from which the introduced nucleus can lead to the formation of an embryo. The embryos are then transplanted into sheep and lambs are born naturally. This technology could allow the production of genetically identical groups of animals which possess a desirable genetic trait.

Cloning technology of sheep

The unfertilised eggs are flushed out of a sheep which has been induced to produce a larger than normal number of eggs. Previously a sample of tissue was from the udder of a six year old ewe was taken and cultured in a dish (Dolly 1). The cultured cells are starved to send them into a resting or quiescent state. A cell is placed beside the egg and an electric current used to fuse the couplet. The reconstructed embryo is put into culture and grows for seven days. Embryos which grow successfully are taken and transferred to a sheep which is at the the same stage of the oestrus cycle as the egg. The sheep becomes pregnant and produces a lamb after 21 weeks (Dolly).

Transgenic Technology

An animal whose genetic composition has been altered to include selected genes from other animals or species by methods other than those used in traditional breeding.

Methods of Producing Transgenics

Superovulation – The donor animals are treated with pregnant Mare Serum Gonadotropin (PMSG)/follicle stimulating hormone-like to increase number of developing follicles. They are also administered with human chorionic gonadotropin (hCG)/ luteinizing Hormone-like to induce ovulation.Ovulation occurs every 21 days ( Cow, horse) and 16 days (sheep, goat).In well managed domestic cattles, 8 – 10 eggs are superovulated. Antral ( graffian follicles) are collected by laproscopic surgery. Recovered follicles are allowed to grow in vitro. Slaughterhouse ovaries also often used in livestock.
In vitro fertilization - IVF is carried out in micro droplets of culture medium. Each micro droplet contain 10 oocytes and 1 million sperms per ml (one dose).
Insertion of Recombinant DNA into Embryo – recombinant DNA is inserted into embryos using the techniques of Calcium phosphate precipitation or microinjection or retroviral infection or particle gun delivery or electrophoration
In vitro oocyte maturation (IVM) – the embryos are grown in the culture medium from cleavage stage to morula stage.
Embryo Transfer Technology - Recipients are estrus synchronized with donor during the previous estrous cycle. Prostaglandin F2-alpha is commonly used to cause luteolysis. Surgical and non-surgical means are used in the transfers.
Gestation and Parturtion - In normal reproduction an animal produces about 4-5 offsprings in a lifetime. IVF technology can produce 50-80 offsprings in a lifetime.

Applications 

“Gene pharming", i.e. the use of transgenic animals to manufacture (human) proteins with therapeutic use, e.g. in their milk. The active ingredients from biogenetic manufacturing processes (such as insulin, blood factors or other human bodily substances) can be obtained in much purer form. Production of active ingredients can be on a large scale and relatively cheap. Hazards to people (pathogens) can be avoided as far as possible by careful testing of drugs.

Cloning could be used in producing transgenic animals as animal models for human diseases. Animal models are used to study the biochemical and physiological processes, human diseases and possible therapies. New drugs can be tested in animal models for their toxicity and pharmacological effect on humans. 

Xenotransplantation is transplanting animal organs into humans. Cloning of "donor animals",are made with the desired genetic modifications using nucleus transfer. The alien animal organ will perform its function in the human recipient.

Animal cloning will increase the genetic knowledge of productive animals. Animal cloning technologies will make the "production" of transgenic animals with modified (agricultural) characteristics. The goals for gene transfer in livestock breeding in combination with cloning are: quality enhancement, gene pharming, boosting resistance to disease, and cost reduction.

Benefits of human cloning

By gene cloning, it is possible to reverse the aging process. It is possible to treat heart attack victims by cloning their healthy heart cells and injecting them into the areas of the heart that have been damaged. Embryonic stem cells can be grown to produce organs or tissues to repair or replace damaged ones. Skin for burn victims, brain cells for the brain damaged, spinal cord cells for quadriplegics and paraplegics, hearts, lungs, livers, and kidneys could be produced.The conditions such as Alzheimer's disease, Parkinson's disease, diabetes, heart failure, degenerative joint disease, and other problems may be made curable. Human cloning could make it possible for infertile couples to have children . In plastic, reconstructive, and cosmetic surgery, instead of using materials foreign to the body for such procedures, doctors will be able to manufacture bone, fat, connective tissue, or cartilage that matches the patient’s tissues exactly. It is possible to inactivate defective genes. Women at high risk for Down's syndrome can avoid that risk by cloning. The autosomal recessive genetic disorder, Tay-Sachs disease could be prevented by using cloning. It is possible to clone livers for liver transplants. It is possible to clone kidneys for kidney transplants. It is possible to clone the bone marrow for children and adults suffering from leukemia. It is possible to switch cells on and off through cloning and thus be able to cure cancer. It is possible to produce effective genetic therapy against cystic fibrosis. It is possible to grow nerves or the spinal cord back again when they are injured. Cloning technology can be used to test for and perhaps cure genetic diseases.

Human impact on the Natural Environment

The term "environment" means the surroundings of a living creature. It is an immediate surrounding which helps to sustains life. An ecosystem is according to the Millennium Report (2003) defined as “a dynamic complex of plants, animals and microorganism communities and the nonliving environment, interacting as a functional unit. Humans are an integral part of ecosystems.” Ecosystems are the planet’s life-support systems - for the human species and for all other forms of life. Humans have become powerful agents of global environmental change. It is obvious that changes in any single component of the earth’s system may affect the entire system.Environmental threats now violate national boundaries. Wind currents, rain patterns, rivers and streams carry pollutants hundreds or even thousands of kilometers from their source. The global environmental problems like climate change, ozone depletion, deforestation, loss of biodiversity threatens all nations. Ecological issues have become a central feature of international relations.

                 

Human induced environmental changes

• Pollution of atmosphere, hydrosphere, and geosphere
• Global warming
• Deforestation
• Loss of ecosystems
• Reduced biodiversity and more.
• Each change triggers another.

Human population growth

It is the number one threat to the world's environment. Each person requires energy, space and resources to survive, which results in environmental losses. Currently, the world human population stands at just over 6 billion people and is increasing at a rate of 1.6% per year. The world’s population presently grows by about 250,000 people per day. Given the current rate of growth, the world’s population will reach 7 billion by 2010 and nearly 8.4 billion by 2025.Human population is rapidly rising beyond the earth's ability to regenerate and sustain with a reasonable quality of life. We are exceeding the carrying capacity of our planet. Over-population leads to: resource depletion, resource degradation, pollution and loss of biodiversity

Modernization of agriculture 

It has a greater harmful effect on the air, soil, water and biodiversity. Pesticides have several characteristics that cause extensive damage to ecosystems: high stability, high mobility and biological magnification. Bioaccumulation increases the concentration of a pollutant from the environment to the first organism in a food chain. Biomagnification increases the effects of pollutants in the environment through food chains. Salinization and water logging of soil is caused due to heavy irrigation practices. Too much of water used to irrigate only 18% of world’s cropland. Intensive agriculture practices leads to pollution from pesticide use, fertilizer run-off, nitrate buildup, salts and phosphates ( from livestock wastes, commercial inorganic fertilizers). Clearing of grasslands & deforestation to support grazing and urbanization lose wildlife and destroy habitats and decrease biodiversity.

Deforestation

Forests around the world being destroyed for lumber, for fuel and for agriculture. (e.g. "slash-and-burn" agriculture). Tropical rainforests are disappearing at an alarming rate. Destruction of forest impacts on all organisms that live there- increasing extinction rates. Soils become nutrient poor. Soil erosion results in soil loss and increased sediments in rivers, lakes and estuaries.

Desertification 

Overgrazing results in removal of vegetation and exposing of soil to wind and water erosion. Grasslands become unusable desert. High rates of topsoil erosion occur due to overgrazing.

Air pollution 

Pollution of air results from human activities such as burning fossil fuels (oil, coal, and gasoline) to create electricity and power automobiles, and manufacture industrial products such as chemicals and plastic. These human activities release waste products such as particulates, HC, CO2, CO, NO, NO2, SO3 -- source may be industrial, autos, etc. The increased carbon dioxide in the atmosphere contributes to the warming of the global climate, the so-called "greenhouse effect." In 1850, atmospheric carbon dioxide was about 280 parts per million (ppm). Today, it is about 350 ppm. Elevated CO2 means an increase in global temperature. Global Warming is increase in the average temperature of the atmosphere, oceans, and landmasses of Earth. Another human impact on the atmosphere has been depletion of the stratospheric ozone. Chlorofluoro-carbons used as coolants in air conditioners and refrigeration units destroy ozone when released into the atmosphere. Each 1% drop in stratospheric ozone is thought to increase human skin cancer rates by 4-6%. The United Nations Environment Program predicts a 26 percent rise in cataracts and non-melanoma skin cancers for every 10% drop in ozone. This translates to 1.75 million cases of cataracts and 300,000 more cases of skin cancer every year. Ozone is considered a pollutant at ground level. Breathing O3 affects both the respiratory and nervous systems, resulting in respiratory distress, headache, and exhaustion. The extra acidity in rain (acid rain) comes from the reaction of primary air pollutants, primarily sulfur oxides and nitrogen oxides, with water in the air to form strong acids (like sulfuric and nitric acid). The main sources of these pollutants are vehicles and industrial and power-generating plants.

Land Degradation 

It refers to loss of quality and productive capacity of soil. It includes the loss of organic matter, the reduction of vegetative cover and biodiversity, a general decline in soil life and fertility. Soil degradation results in compaction, erosion, a reduction in water holding capacity and increased salinization. Soil is getting thinner, “tired” and “worn out”. About 22%of all cropland degraded since 1945. One quarter of the world’s agricultural land has been severely degraded.

‘Soil is a living system’. A fertile soil is a living soil containing billions of living organisms in every cubic centimetre. Earth is not just our home. It is our mother provider and protector. A clean earth is the best inheritance, we can give our future generations.

Water Pollution 

Pollutants in water include a wide spectrum of chemicals   and pathogens. Many of the chemical substances are toxic. Pathogens can produce  waterborne diseases in either human or animal hosts. Alteration of water's physical chemistry include acidity, electrical conductivity , temperature, and eutrophication. Eutrophication is the  fertilization of  surface water by nutrients. Water-associated infectious diseases claim up to 3.2 million lives each year, approximately 6% of all deaths globally. The burden of disease from inadequate water, sanitation, and hygiene totals 1.8 million deaths.

Water is essential for life. There can be no life without water. ‘Water is life, do not waste it’

Threats to Biodiversity

Habitat loss and destruction is usually a direct result of human activity and population growth. It is a driving force in the loss of species, populations, and ecosystems. When the habitats become smaller, less food and shelter are available. As a result, species living in these habitats compete with each other and with humans for limited resources.

Alterations in ecosystem composition cause the loss or decline of a species. Introduction of exotic (non-native) species affect native species by eating them, infecting them, competing with them, or mating with them. Over-exploitation (over-hunting, over-fishing, or over-collecting) of a species or population can lead to its demise. Human-generated pollution and contamination can affect all levels of biodiversity. Global climate change can alter the adaptation of species and populations.

“Man has lost the capacity to foresee and to forestall. He will

end by destroying the Earth” - -Albert Schweitzer, quoted by Rachel Carson, in her Book  “Silent Spring”, (1962)

Stem Cell Technology

A stem cell is a "blank" cell/ precursor cell that can give rise to multiple tissue types such as a skin, muscle, or nerve cell. A stem cell is essentially the building block of the human body.

Properties of stem Cells

Stem Cells are very unique cells. Stem Cells have the amazing ability to develop into several distinct cell types in the body. Stem Cells can be used as a repair system for the body. Stem Cells can theoretically divide without limit in a living organism in order to replenish various types of cells. When a stem cell divides, each new cell has the potential to either remain a stem cell or become another type of cell with a more specialized function (i.e. a muscle cell, a red blood cell, a brain cell, etc.).

Unique properties of stem cells

Stem cells are capable of dividing and renewing themselves for long periods; They are “unspecialized” and they can give rise to specialized cell types. A stem cell is "uncommitted," until it receives a signal to develop into a specialized cell.
Asymmetric division of stem cells - Stem cells have the ability to divide asymmetrically . One portion of the cell division becomes a differentiated cell while the other becomes another stem cell.
Stem cells are unspecialized - A stem cell does not have any tissue-specific structures that allow it to perform specialized functions. A stem cell cannot work with its neighbors to pump blood through the body (like a heart muscle cell); It cannot carry molecules of oxygen through the bloodstream (like a red blood cell); and it cannot fire electrochemical signals to other cells that allow the body to move (like a nerve cell).
Stem cells are capable of dividing and renewing themselves for long periods - Stem cells may replicate many times. When cells replicate themselves many times it is called proliferation. The stem cells that proliferate for many months in the laboratory can yield millions of cells. Stem cells are capable of long-term self-renewal.
Stem cells can give rise to specialized cells - When unspecialized stem cells give rise to specialized cells, the process is called differentiation. There are signals inside and outside cells that trigger stem cell differentiation. The internal signals are controlled by a cell's genes. The external signals include chemicals secreted by other cells, physical contact with neighboring cells, and certain molecules in the microenvironment.
Stem cells exist in both embryos and adults - In embryos, stem cells function to generate new organs and tissues. In adults, they function to replace cells during the natural course of cell turnover.
Distinguishing Features of Progenitor/Precursor Cells and Stem Cells - A stem cell is an unspecialized cell that develops into a variety of specialized cell types. A stem cell divides and gives rise to one additional stem cell and a specialized cell. Example: a hematopoietic stem cell produces a second generation stem cell and a neuron.
A progenitor cell (a precursor cell) is unspecialized that is capable of undergoing cell division and yielding two specialized cells. Example: a myeloid progenitor/precursor cell undergoing cell division to yield two specialized cells (a neutrophil and a red blood cell).

Embryonic Stem Cells

Embryonic Stem Cells are derived from embryos that develop from eggs that have been fertilized in vitro. Embryonic Stem Cells are never derived from eggs fertilized inside of a woman's body. The embryos from which Human Embryonic Stem Cells are derived are typically four or five days old and are a hollow microscopic ball of cells called the blastocyst.
They are capable of undergoing an unlimited number of symmetrical divisions without differentiating (long-term self-renewal). They exhibit and maintain a stable, full (diploid), normal complement of chromosomes (karyotype). Pluripotent ES cells can give rise to differentiated cell types that are derived from all three primary germ layers of the embryo (endoderm, mesoderm, and ectoderm).

Adult type stem cells

Adult stem cells are undifferentiated cells. They are found in small numbers in most adult tissues. They can also be extracted from umbilical cord blood. They are also called “somatic stem cells.”They are multipotent in nature. They give rise to a closely related family of cells within the tissue. An example is hematopoietic stem cells, which form all the various cells in the blood.
Sources of adult stem cells
Umbilical Cords, Placentas and Amniotic Fluid - Adult type stem cells can be derived from various pregnancy-related tissues.
Adult Tissues - In adults, stem cells are present within the bone marrow, liver, epidermis, retina, skeletal muscle, intestine, brain, dental pulp and elsewhere.
Cadavers - Neural stem cells have been removed from specific areas in post-mortem human brains as late as 20 hours following death.

Comparison of embryonic and adult stem cells

Advantages of Embryonic Stem Cell 

1. Flexible - appear to have the potential to make any cell.

2. Immortal - one embryonic stem cell line can potentially provide an endless supply of cells with defined characteristics.
3. Availability - embryos from in vitro fertilization clinics.
Disadvantages of Embryonic Stem Cell
Difficult to differentiate uniformly and homogeneously into a target tissue.
Immunogenic - embryonic stem cells from a random embryo donor are likely to be rejected after transplantation
Tumorigenic - capable of forming tumors or promoting tumor formation.
Destruction of developing human life.

Advantages of Adult Stem Cell

Adult stem cells from bone marrow and umbilical cords appear to be as flexible as the embryonic type

• Somewhat specialized - inducement may be simpler. 
• Not immunogenic - recipients who receive the products of their own stem cells will not experience immune rejection. 
• Relative ease of procurement - some adult stem cells are easy to harvest (skin, muscle, marrow, fat) 
• Non-tumorigenic-tend not to form tumors. 
• No harm done to the donor.

Disadvantages of Adult stem cells

1.Limited quantity - can sometimes be difficult to obtain in large numbers.
2. Finite - may not live as long as embryonic stem cells in culture.
3. Less flexible - may be more difficult to reprogram to form other tissue types

Potential sources of stem cells

Fetal tissue that becomes available after an abortion. Excess embryos from assisted reproductive technologies such as commonly used in fertility clinics. Embryos created through in vitro fertilization specifically for research purpose, and embryos created asexually as a result of the transfer of a human somatic cell nucleus to an egg with its own nucleus removed. Other sources of stem cells are those from umbilical cord blood, and bone marrow. In addition, neural stem cells, haematopoetic stem cells and mesenchymal stem cells can be harvested from fetal blood and fetal tissue.

Classification of stem cells based on level of differentiation

Totipotent stem cells - The fertilized egg is said to be totipotent from the Latin totus, meaning “entire”. It has the potential to generate all the cells and tissues that make up an embryo. It supports embryonic development in utero.

Pluripotent stem cells - are descendants of the totipotent stem cells of the embryo. These cells develop about four days after fertilization. They can differentiate into any cell type, except for totipotent stem cells and the cells of the placenta. “Pluri” is derived from the Latin plures means several or many. Thus, pluripotent cells have the potential to give rise to any type of cell.

  Multipotent stem cells - are descendents of pluripotent stem cells and antecedents of specialized cells in particular tissues. For example, hematopoietic stem cells, which are found primarily in the bone marrow, give rise to all of the cells found in the blood, including red blood cells, white blood cells, and platelets.

Unipotent stem cells - a term that is usually applied to a cell in adult organisms, means that the cells in question are capable of differentiating along only one lineage. "Uni" is derived from the Latin word unus, which means one.

Umbilical cord stem cells - Blood from the placenta and umbilical cord that are left over after birth is a rich source of hematopoietic stem cells. These so-called umbilical cord stem cells have been shown to be able to differentiate into bone cells and neurons, as well as the cells lining the inside of blood vessels. Cord blood stem cells have been used to treat 70 different diseases, including leukemia, lymphoma, and inherited diseases (of red blood cells, the immune system, and certain metabolic abnormalities). Cord blood collection is a safe, simple procedure that poses no risk to the mother or newborn baby.

Stem Cell therapy.

• Treatment of neural diseases such as Parkinson's disease, Huntington’s disease and Alzheimer's disease. 
• Stem cells could be used to repair or replace damaged neurons.
• Repair of damaged organs such as the liver and pancreas. 
• Treatments for AIDS. 

Stem cell transplantation (SCT) is the term now used in preference to bone marrow transplantation (BMT). When a patient's bone marrow fails to produce new blood cells, for whatever reason, he or she will develop anaemia, be prone to frequent, persistent infections and may develop serious bleeding problems. In order to restore blood cell production a patient may be given healthy stem cells.
Intense chemotherapy in cancer patients damages a person’s bone marrow, where the stem cells for blood reside. Depleted of a fresh supply of blood cells, the patient is left vulnerable to infection, anemia and bleeding. These side effects of chemotherapy are often treated with a bone marrow transplant.

Digital tools in teaching - learning

Technology integration is the use of technology resources (computers, Internet etc.) in daily classroom practices, and in the management of a College. Computer based education refers to any kind of computer in educational settings. Computer technology is becoming increasingly important for education at every level. The computers make it possible to access, represent, process and communicate information in new ways. The computers make it possible to search and organize information, analyse data, represent ideas, simulate complex systems and communicate with others. They also enable new ways of teaching – learning , new activities, new products and new types of learning. Computers are cognitive tools; Computers are performance support systems (PSSs). Computers offer multi-media ways for obtaining large amounts of information, e.g., CD-ROMs and web sites.

Computers can be used in two ways

1.       The computer as a classroom tool

2.       The computer as a subject of instruction.

Internet and world wide web

The Internet consists of a vast collection of independent computers linked by national and international tele-communication networks.  Each Internet site contains information (text, images, audio, video, links etc.) which are accessible to the individual working from their home computer. Internet sites are increasing in number, sophistication and content.

Internet provides information in text, graphics, audio and video. New programming allows a greater degree of interactivity through real time audiovisual transfers and chat.  Coloured and animated graphics are of much greater educational value than photocopied images

The World Wide Web is a much hyped Internet application which potentially provides great flexibility in the distribution of teaching and learning resources in interesting fashion. Resources such as lecture notes, readings, tutorials and assignments can be delivered to, and received from, students both on and off campus. The learner searches website, collects information and learns the lesson. Web is a viable tool to help students gain education without being on campus. It allows greater autonomy of learning.

e-mail –messages are stored and sent via a computer system, transmitted across networks typically accessible only by the addressee.

E-learning applications

On - line students group: allows students to interact with each other

On - line lecturing: allows faculty to interact with students

On - line counseling: helps students in decision- making

On - line libraries and resource center: providing text, documents, articles for reference.

Multimedia tools

Students who use multimedia tools are active learners. Students reflect these kind of tasks throughout their life. Students work collaboratively, not only with each other, but with researchers and teachers.

Power point Presentation

It provides a platform for incorporating a variety of different kinds of multi-media file types: images, video, audio and animations. It is neat and clean and it allows for portability of materials. It is easy for professors to update, saving them time and energy.

Hypermedia tools

An approach to information storage and retrieval that provides multiple linkages among elements. It allows the user to navigate easily from one piece of information to another. It consists of a database of information structured as nodes or frames. It links between the nodes that allow rapid movement through the information and a user interface. Hypermedia tools are useful for exploring a large database of information, accessing elaborations on core information and promoting a ‘rich’ learning.

Hypertext tools

The linking of information together by highlighted keywords that have been marked up creating paths through related material from different sources such as footnotes and encyclopedias. Hypertext has the ability to connect related documents. Hyperlink is a connection among documents in a hypermedia and hypertext format.

Simulation tools

A computer simulation attempts to reproduce real-life situations. Simulations feature a combination of text and graphics ,using dialogue and inquiry to guide the student through a situation. Simulations also can bring about higher-order synthesis and analysis skills.

           Tutorials 

          They are one of the most common types of computer-assisted instruction. Tutorials are “page- turners” similar to textbooks. The one-to-one tutoring and feedback provided by a tutorial can make it an excellent tool for improving student knowledge. Drill-and-practice programs work well in increasing student knowledge through repetition, usually through cues.Students can repeat sections, helping individualized instruction. Drill-and-practice programs provide automatic feedback to learners.

Interactive video  and video Conferencing  applications

The interactive video refers broadly to software that responds to certain choices and commands by the user. A typical system consists of a combination of a compact disk, computer and video technology. Videodisc systems store video pictures, still pictures, and sound on discs that users can control with a videodisc player. These systems can provide the interactive capabilities of computers and the motion-picture capabilities of videos.
Video Conferencing is a method of performing interactive video communications over a regular high speed internet connection. It is a medium where individuals or groups can meet face-to-face in real time to interact and exchange ideas. It requires a fast speed internet connection, a microphone and a video camera. Since it was introduced, communication technologies have improved exponentially.

A digital library is a collection of textual, numeric, graphic, audio and video data stored in digital form, indexed and logically linked for ease of retrieval. The user can access information from anywhere in the world. Digital library allows ease of search and retrieval of information.

Time Management Skills

Time is a period during which an action, process or condition exists or continues.Time is a scarce resource(‘time is gold’). It is more valuable than money as money can be earned (‘time is money’). Time is fixed and we cannot change it. Every human being on earth has same amount of time -60 seconds in a minute; 60 minutes in an hour; 1,440 minutes in a day and 525,600 minutes in a year. You can't recycle wasted time. Managing time is like managing one's life. Achieving personal success requires efficient and productive use of time. Time management is the method that is used to organize one's time. Crucial to time management is an understanding of the difference between efficiency and effectiveness. Efficiency is doing things right. Effectiveness is doing the right things - in order to produce results.Time management is a skill that can be learned, practiced and mastered with determination and repetition. People who manage their time effectively have learned to structure their lives.Time Management involves knowing our goals, deciding on our priorities, anticipating future needs and making possible changes. It is all about controlling our life by controlling our time. It is about making commitment to be punctual without procrastinating. We must carry out our plans as per our schedule.

Definitions

Time management (TM) can be defined as the ability to prioritize, schedule and execute one’s daily responsibilities to a level of personal satisfaction. 

Time management (TM) is a set of principles, practices, skills, tools and systems working together to get more value out of our time with the aim of improving the quality of our life.

Pickle jar theory of time management 

We need to prioritize our activities and recognize our ‘big rocks’. We need to allot time in accordance with the priority. Big rocks are things of first importance which takes more time. Smaller rocks are urgent things but not so important. Sand goes in on top of the smaller rocks and creeps all around the big rocks i.e., activities thrust upon us from all directions and which cause a lot of upsets.

The Eisenhower decision matrix

The Eisenhower matrix is one of the simplest prioritization frameworks that categorize tasks either important and/or urgent. This quadrant was proposed by U S president Dwight D.Eisenhower. It is based on the principle of “what is important is seldom urgent and what is urgent is seldom important.” Based on this, a task would end up in one of the four categories measured in two distinct dimensions: Urgent/Not urgent or Important/Not important. Urgent means that a task requires immediate attention. Important tasks are tasks that contribute to our long-term mission, values and goals. Priority 1 tasks are tasks that are both urgent and important. These tasks need to be addressed personally and immediately. Priority 2 tasks are tasks that are important but not urgent. These tasks need to be addressed personally but not immediately so they need to have a planned date. Priority 3 tasks are tasks that are urgent but not important so they require immediate attention, but necessarily by you. Priority 4 tasks are tasks that are neither urgent nor important so they are mostly a waste of time. Always use the Eisenhower method, when adding tasks to your to do list. Always ask yourself whether it is important and whether it is urgent. In general, you can make a goal of spending at least 80% of your time in the ‘Not urgent and important’ quadrant. The other 20% will be divided between ‘Urgent and important’ and ‘urgent and not important.’

The 80/20 rule of time management

Italian Economist Vilfredo Pareto observed in 1906 that 80% of wealth in Italy was controlled by 20% of the Italian population. The 80/20 rule or Pareto principle works everywhere in life.The 80/20 rule says that 80% of what a person achieves is derived from 20% of the time the person expends.Every time more with less is possible, provided that we identify the golden 20%: the people, methods, time and methods that are extremely creative and productive. we devote 20% of our time to activity that is central to our aims and 80% on activity that is of marginal importance.

Elements of good time management

Macan(1994) identified three elements of time management (1) setting goals and priorities (2) mechanics (i.e. making to-do lists and scheduling) and preference for organization(i.e. one’s preference for organization in his/ her work space and approach to tasks or projects).Time management generally involves a five step process: setting priorities, analyzing, filtering, scheduling and executing.

Prioritize your time – Planning better defines the course of action that we propose to undertake. Our current choices actually reflect our responsibilities. We must clarify what is of greatest importance to our work/ life.

ABC priority system - Section A :items that need to be done that day; Section B : items that need completion within the week, and Section C : items that need to be done within a month. B and C items move up to the A or B lists as they become more pertinent.
Analyse your time use – we must find our biological prime  time.  We must defend it ruthlessly and spend it usefully. We must also find our dead time. We must schedule our timings based on our good and bad times.

Organize your time - Time is an equal opportunity resource: everyone gets 168 hours per week. Time is elusive and easy to ignore. Time is a non-renewable resource.Time seems to pass at varying speeds.

Schedule you time – Scheduling activities consists of allocating time to activities. “Failing to plan is planning to fail.” We must plan for each day, each week and each semester. We can always change your plan, but only once you have one! Activities should be grouped by topics.

The three-part scheduling plan 

• The master schedule 
• The weekly schedule 
• The daily schedule

Using a Daily Planner

• Complete a term assignment preview.
• Use a “week at a glance” organizer.
• Enter in due dates and social events as soon as you can.
• Review your calendar daily for the current week and upcoming week
• It just takes a moment to review your calendar and it can help relieve stress.

Executing the plan
Execution is the implementation of an established schedule. Sticking to a schedule provides greater control,saves time, provides freedom and increases flexibility.It makes tasks more manageable and helps us to work at peak efficiency.

Symptoms of Poor Time Management

Poor time management affects every part of our life from work to relationships. Symptoms or signs of poor time management are the following:

• A lack of achievement.
• Always missing deadlines 
• More time spent socializing at work.
• More time on the telephone.
• Indecisiveness leading to delayed work.
• Constantly interrupting others and being interrupted.

Barriers to good time management

Some of the barriers to good time management are the following: keeping too many things in our head; attempting to do “too much”;doing whatever grabs our attention next; not spending enough time on our top priorities; poor Planning; working in a disorganized and distracting environment; always saying “YES”; not managing our inflows and confusing activity with productivity.

Time Management Tips

Two main ways to control time - saving the time and allocating it  as per schedule.

• Learn to say NO assertively.
• Plan for change; it’s inevitable.
• Finish fully; it’s energizing and  motivating.

Time robbers/time stealers

Time robbers are behaviors that steal your valuable time away from responsibilities that really need attention. Time robbers can be persons or things that literally suck the energy out of your life. It includes telephone calls, poor planning, attempting to do too much, drop- in visitors, poor delegation, personal disorganization, lack of self discipline, can’t say ‘no’ and procrastination.

Benefits of good time management

The benefits of effective time management are numerous. With good time management skills one is in control of one’s time, stress and energy levels. One can maintain balance between one’s work and personal life. Good time management improves the quality of one’s life. You will get more time for making progress or enjoying life. Good time management boosts an individual’s self-esteem and self-confidence. Good time management makes an individual punctual and disciplined. Time management is the key to better productivity and job performance. Time management helps an individual less prone to stress and anxiety. With effective time management, you can save your health.

Concluding thoughts

Using Time to our benefit can create a sense of satisfaction and can help us to balance our work. Spending one minute planning saves four or five minutes in getting a task done. It can reduce stress and improve our health and  our career.

Quotes for reflection

"Time is the coin of your life. It is the only coin you have, and 
  only you can determine how it will be spent. 
  Be careful lest you let other people spend it for you."
                                                                         - Carl Sandburg.
"Time is what prevents everything from happening at once." -John Archibald Wheeler.

"Time is the longest distance between two places." - Tennessee Williams.

"Time is at once the most valuable and the most perishable of all our possessions."
  -John Randolph.

"Lost time is never found again." -Proverb.

"To choose time is to save time." -Francis Bacon.

"There is a time for everything, and a season for every activity under heaven." 

  -ECCLESIASTES 3:1