Science and technology

LG Optimus Pad

noreply@blogger.com (prem) — Thu, 03 Mar 2011 13:30:00 +0000

LG steps into the tablet game with the 3D-recording Optimus Pad.

LG Optimus Pad

Until this year's MWC, tablets came in two basic sizes: iPad-size (around ten inches) and "ultraportable" (around seven inches), a la Samsung Galaxy Tab and the still unreleased BlackBerry PlayBook). LG, however, has opted for something right in the middle, and so the screen on their new LG Optimus Pad is a comfortable 8.9-inch display, which LG reckon is perfectly balanced for watching movies and holding with one hand.

The design of the Optimus Pad is very familiar, with the standard black bezel surrounding the display. Beneath the glossy black shell lurks a dual-core processor and 1GB of RAM.

For those not familiar with what this device has to offer here is a quick recap of its specs, this 8.9inch device offers a 1280×768 display with WXGA resolution, runs on Android 3.0 Honeycomb, has both front and rear facing cameras-with the ability to shoot 3D video, runs super fast due to its 1GHz NVIDIA Tegra 2 processor and packs a whopping 32GB of internal storage.

Apple ipods

noreply@blogger.com (prem) — Sun, 03 Oct 2010 06:13:00 +0000

Apple ipods

The iPod was a portable media player first designed and marketed by Apple and launched on October 23, 2001. The product line-up currently consists of the hard drive-based the iPod Nano, iPod Classic, the touchscreen iPod Touch and the compact iPod Shuffle. The iPod Classic models store media on its internal hard drive, while all other models use flash memory.The iPods can also serve as external data storage devices like other digital music players. Storage capacity ranges from 2 GB for the iPod Shuffle to 160 GB for the iPod Classic. All of the models have been redesigned multiple times since their introduction. The most recent iPod redesigns were introduced on September 1, 2010.

The iTunes software by Apple can be used to transfer music to the devices from computers using certain versions of Microsoft Windows operating system and Apple Macintosh.There are several open source alternatives are available for the iPod to users who choose not to use iTunes or whose computers cannot run iTunes. iTunes and its alternatives can be used to transfer videos, games, contact information, photos, e-mail settings, Web bookmarks, and calendars to iPod models that support those features.

The iPod branding is used for the media player applications included with the iPhone and iPad; the iPhone version is essentially a combination of the Music and Videos apps on the iPod Touch therefore function as iPods, but they are generally treated as separate products.
The name iPod was proposed by Vinnie Chieco, a freelance copywriter, who was called by Apple to figure out how to introduce the new player to the public. A Space Odyssey and the phrase "Open the pod bay door, Hal!", which refers to the white EVA Pods of the Discovery One spaceship. Apple researched the trademark and found that it was already in use. Joseph N. Grasso of New Jersey had originally listed an "iPod" trademark with the U.S. Patent and Trademark Office (USPTO) in July 2000 for Internet kiosks. The first iPod kiosks had been demonstrated to the public in New Jersey in March 1998, and commercial use began in January 2000, but had apparently been discontinued by 2001. The trademark was registered by the USPTO in November 2003, and Grasso assigned it to Apple Computer, Inc. in 2005.
All of the models have been redesigned multiple times since their introduction. The most recent iPod redesigns were introduced on September 1, 2010.

Motorcycle-The Bike

noreply@blogger.com (prem) — Sat, 02 Oct 2010 04:12:00 +0000

Motorcycle-The Bike
A motorcycle is a two-wheeled,engine-powered,a single-track motor vehicle. Motorcycles vary considerably depending on the task as they are designed, such as navigating congested urban traffic,long distance travel,cruising, sport and racing, or off-road conditions.

They are one of the most common,most affordable forms of motorized transport in the world and,for most of the world's population.There are around 200 million motorcycles (including mopeds, motor scooters and other powered two and three-wheelers) used worldwide,or about 33 motorcycles per 1000 people.Most of the motorcycles,about 58%, are in the developing countries of Asia—Southern and Eastern Asia and the Asia Pacific countries, excluding Japan.But 33% of the cars (195 million) are concentrated only in the United States and Japan. As of 2002 data, India with an estimated 37 million motorcycles/mopeds was home to the largest number of motorized two wheelers in the world while China came a close second with 34 million motorcycles/mopeds.

Motorcycle is the engineering,manufacturing,and assembly of components and systems for a motorcycle that results in the performance,aesthetics and cost desired by the designer. The construction of motorcycles has standardized on a steel or aluminum frame, telescopic forks that folds the front wheel,and disc brakes. Some other body parts, designed for either aesthetic or performance reasons may be added. A petrol powered engine typically consisting of between one and four cylinders coupled to a manual five- or six-speed sequential transmission drives the swing arm-mounted rear wheel by a chain, drive shaft or belt.

The fuel economy varies greatly with engine displacement and riding style, ranging from a low of 29 mpg-US (8.1 L/100 km; 35 mpg-imp) reported by a Honda VTR1000F rider, to 107 mpg-US (2.20 L/100 km; 129 mpg-imp) reported for the Verucci Nitro 50 cc Scooter.But a specially designed Matzu Matsuzawa Honda XL125 achieved 470 mpg-US (0.50 L/100 km; 560 mpg-imp) "on real highways - in real conditions." Due to lower engine displacements (100 cc–200 cc), motorcycles in developing countries offer good fuel economy. In the Indian market, the second best selling company, Bajaj, offers two models with superior fuel economy: XCD 125 and Platina with 125 cc. The motorbikes with a company-claimed fuel economy of 256 mpg-US (0.919 L/100 km; 307 mpg-imp) and 261 mpg-US (0.901 L/100 km; 313 mpg-imp),respectively.

Electric motorcycles with Very high fuel economy are nearly silent, zero-emission electric motor-driven vehicles.Fuel cells and petroleum-electric hybrids are also under development to extend the range and improve performance of the electric motors where operating range and top speed suffer due to limitations of battery technology.

Acid Rain and its damages

noreply@blogger.com (prem) — Sun, 26 Sep 2010 11:07:00 +0000

Acid Rain and its damages
Acid rain is a form of air pollution in which acids produced by electric utility plants and other sources fall to earth in distant regions. The acid rain causes widespread damage to the environment due to its corrosive nature. The main causes of acid rain is the production of sulfur dioxide and nitrogen dioxides from the burning of fossil fuels, such as coal, natural gas,oil, etc. These sulfur dioxides and nitrogen oxides react with water and other chemicals in the air to form sulfuric acid, nitric acid, and other pollutants which reach high into the atmosphere and eventually return to the ground by way of rain, snow or fog and as invisible "dry" forms.
Acid pollutants also occur as dry particles and gases, which may reach the ground without the help of water. When these "dry" acids are washed from ground surfaces by rain, they add to the acids in the rain itself to produce a still more corrosive solution. The combination of acid rain and dry acids is known as acid deposition.

The damage of acid rain has been widespread in eastern North America and throughout Europe, and i Japan, China, and Southeast Asia.the acid rain leaches nutrients from soils, slows the growth if trees, and makes lake uninhabitable for fish and other wildlife. In cities acid pollutants corrode almost everything they touch, accelerating natural wear and tear in structures such as buildings and statues. Acids combine with other chemicals to form urban smog, which attacks the lungs, causing illness and premature deaths.

What Is Rainbow?

noreply@blogger.com (prem) — Fri, 24 Sep 2010 13:10:00 +0000

What Is Rainbow?
Rainbow is an arch of light exhibiting the spectrum colors in their order, caused by drops of water falling through the air. It is seen usually in the sky opposite to the sun at the close of a shower and also in spray of waterfalls in the brightest or primary bow, often the only one seen, the colors are arranged with the red outside. Above the prefect bow, in which the colors are arranged in reverse order;this bow is dimmer, because of a double reflection within the drops.
When the sunlight enters a raindrop it is refracted, or bent, by and reflected from the drop in such a way that the light appears as a spectrum of colors. The colors can be seen,however, only when the angle of reflection between the sun, the drop of water, and the observer's line of vision is between 40 and 42 degree.

When the sun is low in the sky the rainbow appears relatively high;as the sun rises higher, the rainbow appears lower in the sky, maintaining the critical 40 to 42 degree angle. When the sun is more than 42 degree above the horizon no rainbow can be seen because the required angle passes over the head of the observer.

Carbon-14 Method of Dating

noreply@blogger.com (prem) — Fri, 24 Sep 2010 12:36:00 +0000

Carbon-14 Method of Dating
Radiocarbon dating techniques was first developed by the american chemist willard F. Libby and his associates at the University of Chicago in 1947. This techniques are frequently useful in deciphering time-related problems in anthropology, pedology, oceanology, archeology, climatology and geology, etc.

Through metabolic activity, the level of carbon-14 in a living organism remains in constant balance with the level in the atmosphere or some other portion of the earth's dynamic reservoir, such as the ocean. upon the dead organism carbon-14 begins to disintegrate at a known rate, and no further replacement of carbon from atmospheric carbon dioxide can take place. The rapid disintegration of carbon-14 generally limits the dating period to approximately 50,000 years, although the method is sometimes extended to 70,000 years. Uncertainty in measurement increases with the age of the sample.

Although the method is suited to a variety of organic materials, accuracy depends on the half-life to be used, variations in levels of atmospheric carbon-14, and contamination. The half-life of radiocarbon was redefined in 1962, so some dates determined earlier required adjustment; and due to radioactivity more recently introduced into the atmosphere, radiocarbon dates are calculated from 1950AD. The radiocarbon time scale contains other uncertainties, as well, and errors as great as 2000 to 5000 years may occur. Postdepositional contamination, which is the most serious problem, may be caused by incorporation of older or younger carbon,percolating groundwater and contamination in the field or laboratory.

Interesting Facts about Mount Everest

noreply@blogger.com (prem) — Sat, 18 Sep 2010 13:19:00 +0000

Interesting Facts about Mount Everest:

Mount Everest is known by many different names; In Tibet it is well known as Chomolungma Or Qomolangma. The Chinese translated this as ShengmO Fcng whereas it is named as Deodungha in Darjeeling that means holy mountain.
Mount Everest is rising from 3 to 6 millimeters a year.
The time to climb Mount Everest is in early May before the monsoon season.
The usual climbing routes Of Mount Everest is The Southeast Ridge from Nepal,called the South Col Route and the Northeast Ridge or the North Col Route from Tibet.
The largest expedition to climb Mount Everest was a 410 climber Chinese team in 1975.
The safest year on Mount Everest was 1993 when 129 climbers were able to reach the summit and only 8 died.
The least safe year on Mount Everest was 1996 when 98 climbers submitted and 15 died. Babu Chiri Sherpa had stayed 21 hours and 30 minutes on the summit of Mount Everest.
The country with most death on Mount Everest is Nepal with 47 (as of 2009).
Though Mount Everest is known as the highest mountain above sea level, records also show other tall mountains on earth. But when measured from the base, Mauna Kea in Hawaii is considered to be tallest mountain-10,200m from base.
A jumping spider lives upto 22,000 feet on Mount Everest.

Vipers

noreply@blogger.com (prem) — Fri, 17 Sep 2010 11:31:00 +0000

Vipers
Viper is a common name for snakes in a family of venomous snakes, characterized by a pair of long, hollow fangs, usually with reserve fangs beside them, in the front of upper jaw. The fangs fold back against the palate when not in use and quickly swing forward to strike, injecting deadly venom to kill its prey and also serve as defense. The viper generally has a broad, triangular head, and the eyes have vertical pupils. Most vipers give birth to living young from eggs hatched inside their mother’s body.

Vipers are distributed throughout most temperate and tropical regions of the world, except Australia. They occur from lowlands to elevations of more than 4500m, from deserts to rain forests, and even in arctic regions.

Vipers are usually divided into two groups: the true vipers, the horned and Gaboon vipers of Africa and the Indian vipers-and the pit vipers, which have a distinctive heat-sensitive pit between the eye and nostril, and which include the rattlesnakes, copperhead, and cottonmouth.

King Cobra, the venomous snake
The aptly named king cobra is the largest venomous snake in the world which is about 5 meters in length. They are aggressive if harassed, and their bite is deadly. When disturbed, it raises its hooded head to get a better view or to strike. Large individual can raise themselves to a height of about 1 meter. They prey on other snakes and frequent bamboo thickets, mangrove swamps, and other densely vegetated habitats. Females may construct a nest chamber in which eggs are laid- the only snake known to do so.

DNA As Genetic materials

noreply@blogger.com (prem) — Sun, 08 Aug 2010 06:29:00 +0000

DNA As Genetic materials

Genetic materials are the substance which can controls the inheritance of trails from one generation to the next and are also able to express its effect through the formation and functioning of the trails. Replication and expression are the two basic characteristics of genetic materials. The genetic material consists of a number of genes.

Functions and requirements of Genetic material

Genetic material must be able to replicate itself.
The genetic material and its genes must contain the hereditary information in the coded form.
The structural elements of the genetic materials must be ubiquitous in their distribution.
It should be present in all the cells.
There should be transformation of replicated genetic material from a cell to its daughter and from one generation to the next.
It should be able to express itself through formation of specific biochemical.
Different parts of an organism are able to have specific size, structure and functions due to the presence of intrinsic control system for different functioning of genetic material or its genes.
The sorts of biological clock in the expression of genetic material govern developments of embryo, juvenile state, mature state, sexual maturation and ageing.
There is an occasional, permanent and inheritable change in the structure and functioning of its genes. It is called mutation.

DNA as Genetic material

The various evidence of DNA being genetic material are as follows:
It occurs in all the cells and is capable of replication.
DNA copies are precisely the same as the original DNA.
It is able to control the cell structure and cell functions through transcription and translation.
DNA replicates prior to cell division and is equitably distributed in the daughter cells.

Death by Thphoid

noreply@blogger.com (prem) — Sun, 01 Aug 2010 09:10:00 +0000

Death by Thphoid

Typhoid is known as enteric fever. It is an acute infection of the intestine. It is characterized by persistent fever, slow pulse, and abdominal tenderness. It is the most common in Kathmandu and other rural parts of the country. It is highly communicable disease. The people suffer from heavy loss of manpower.

Causative organism

This illness is caused by bacterium named Salmonella typhi. It is a rod shaped motile, gram-negative bacillus bacterium. It measures 1.0 to 1.5 μm in length. This bacterium affects human intestine.

Mode of infection

Typhoid is transmitted through contaminated food and water. It is also spread by intestinal discharges. Any person carrying Salmonella typhi in his intestinal tract can also spread the disease to others even though the person himself may not be suffering from the disease. These are healthy carriers. Flies also play role in transmitting bacteria.

Incubation period

The incubation period is 2 weeks on an average.

Symptoms

It is characterized by following symptoms:

Persistent high fever (104⁰F) that lasts for 2-3 weeks and then slowly declines onwards.
Intestine shows lesions, hemorrhage and ulceration.
Other symptoms are slow pulse, abdominal tenderness rose colored eruptions.
Death may occur due to haemorrhage or puncturing of the intestine.

Classically, the course of untreated typhoid fever is divided into four individual stages, each lasting approximately 1 week.

First week:

In the first week, there is slowly rising temperature with relative Bradycardia, malaisc, headache and cough. Epitaxis is seen in a quarter of cases and abdominal pain is also possible. There is Leukopenia with Eosinypenia and relative Lymphocytosis, a positive diazo reaction and blood cultures are positive for Salmonella typhi or paratyphi. The classic widal test is negative in the first week.

Second week:

In the second week of the infection, the patient lies prostrated with high fever in plateau around 40⁰C and bradycardia (Sphygmo-thermic dissociation), classically with a dicrotic pulse wave. Delirium is frequent, frequently calm, but sometimes agitated. This delirium gives to typhoid the nickname of “nervous fever”. Rose spots appear on the lowest chest and abdomen in around 1/3 patients. There are rhonchi in lung bases. The abdomen is distended and painful in the right lower quardant where sound can be heard. Diarrhea can occur in this stage: six to eight in a day, green with a characteristic smell, comparable to pea-soup. However, constipation is also frequent. The spleen and liver are enlarged (hepatosplenomegaly) and tender and there is elevant of licer transa minases. The Widal reaction is strongly positive with antiO and antiH antibobies. Blood cultures are sometimes still positive at this stage.

Third week:

In the third week of typhoid fever a number of complications can occur:

• Intestinal hemorrhage due to bleeding in congested peyer patches; this can be very serious but is usually non-fatal.

• Intestinal perforation in distal ileum: this is a very serious complication and is frequently fatal. It may occur without alarming symptoms until septicaemia or diffuse peritonitis sets in.

The fever is still very high and oscillates very little over 24 hours. Dehydration ensues and the patient is delirious (typhoid state). By the end of third week defervescence commences that prolongs itself in the fourth week.

Control

Antibiotics effective in enteric fever are:

Chloromycetin-drug of choice
Cotrimoxazole
Amoxycillin
Chloramphenicol

Preventive measures

i. Proper sanitation (Health education)

ii. Personnel cleanliness

iii. Sanitary disposal of human excreta

iv. Protection and purification of water

v. Immunization against typhoid (TAB) vaccine.

Some famous person who suffered this disease

•William Wallace Lincoln, third son of President Abraham Lincoln and Mary Todd Lincoln

• President John Adams’s wife Abigail Adams

• Alexander the Great (Typhoid is one of many possibilities of his cause of death)

Smoking Hazard

noreply@blogger.com (prem) — Thu, 29 Jul 2010 08:49:00 +0000

Smoking Hazard

The regular consumption of the tobacco in the form of either cigarettes, or chewing causes dependency on tobacco is called Smoking. The prolonged use of tobacco may lead to the dependency of the body on them is called tobacco addiction. Tobacco is the one of the most abused substances in the world which is made up from the leaves of tobacco plants (Nicotiana tobaccum and N. Rustica).

Smoking is the major cause of death in the world today. According to a report issued by WHO, smoking is currently responsible for the death of about 5 million deaths world wide each year. The report further estimates if current smoking patterns continue, it will cause 10 million deaths each year by 2020.

Smoking harms nearly every organ of the body, causing many diseases and affecting the health of smokers in general. Smoking and consumption of tobacco products in Nepal is a major health problem. Approximately 15,000 people are estimated to die to tobacco consumption every year, according to Nepal Cancer Relief Society report. Furthermore, smoking is the most common risk factor for diseases. According to health reports, tobacco smoke contains more than 4,000 chemical compounds, including at least 43 cancer causing compound.

Causes of Smoking

1. Imitation and pressure of parents and friends

2. To reduce tension and to get relief from pain

3. As a fashion and for personal pleasure

4. Ceremonial and ritualized smoking

5. As an aid to contemplation

Types of Smoking

1. Nicotine

Nicotine is an addictive toxic alkaloid chemical. It is present in cigar; if injected intravenously, can kill a human being. Its regular use causes multiple ill effects.

2. Hemp Plant

There are two species of himp plants; Cannabis Indica and C. Sativa. Their dry leaves and flowers yield various drugs. The drugs prepared by Cannabis in Nepal are as follows:

a) Charas b) Bhang c) Marijuana (Gan

Effects of Smoking

Anesthetized and Senselessness
Confusion and Fears
It causes premature deaths from diseases like cancer, lung problems.
It affects in blood vessels cause chronic pains in the legs.
It reduces women’s fertility.
It delays healing of peptic ulcers of the stomach and duodenum.

Control of Smoking

1. By providing health education and information about the evils of smoking

2. Smoking should be discouraged by community.

3. Strict implementation of law to discourage smoking.

4. Treatment and hospitalization of sick people.

5. Smokers may be suggested for substitutes like chewing gum, cannatas etc.

Drug abuse and Prevention

noreply@blogger.com (prem) — Wed, 28 Jul 2010 10:07:00 +0000

Drug abuse and Prevention

Drug is defined as any chemical substance that alters the physiological state of a living organism. It is any substance that when taken into living organism, may modify one or more of its functions. So drugs are widely used in medicine for the prevention, diagnosis and treatment of disease. They include analgesics, antibiotics, anesthetics, antihistamines and anticoagulants. Those substances work on the nervous system and act either as stimulants to excite it or as depressants which slow down the activity of brain. Some may act as sedative and other cause hallucination.Drug abuse indicates the misuse of drugs. It may be defined as the use of any substance in an illegal and un-medical way that alters the ability of the individual. Self-administration of a drug for non-medical reasons, in quantities and frequencies which may impair with individuals ability to function effectively and which may result in social, physical or emotional harm.

Drug Addiction:

Drugs belonging to the third category are often used by the persons regularly. Their body becomes accustomed to them and may even become dependent. The addicts then feel an intense urge for them, and are physically ill and distressed when deprived of them. Prolonged use of such drugs may lead to the dependence of the body on them. This condition of feeling compelled to take certain drugs is known as drug addiction.

Causes of Drug Addiction

1. A person may experiment because his or her friends suggest it.

2. To satisfy his own curiosity.

3. For the feeling of relaxation.

4. In search of a more satisfying life.

5. To escape from a difficult or unpleasant situation.

6. To increase their working capacity.

7. Students usually take drugs to study all night during examination.

Control measures for Drug Addiction

1. Treatment and hospitalization of sick or addict persons

2. Rehabilitation for the addict persons

3. Psychological treatment

4. Banning of illegal activities like production and selling of drugs that increase anti-social activities. Smuggling of drugs should be prohibited.

5. Enforcement of laws, rules and regulations for the control and supply of drugs.

6. The youth should be motivated to be involved in the fight against drug abuse.

Types of drugs and their effects

Class	Drugs	Particulars	Effects
Depressant and Hypnotics	a. Barbiturates or Downess	Nembutal, Second Tuinal, Amytal	Depress brain activity and produce feelings of calmness, relaxation, drowsiness and deep steep
Depressant and Hypnotics	b. Benzodiazephines	Valium
Stimulants	a. Caffeine	Obtained from Tea, Coffee plants and Cocoa	Affects nervous system, Alertness, Restlessness
	b. Nicotine	Obtained from Tobacco	Affects nervous impulse, musculature relaxation, BP and hear beat
	c. Cocaine	Obtained from Cocoa	Lack of sleep and appetite
Opiate Narcotics	a. Opium	Extracted from unripe capsules of poppy plant	Reduce respiratory and cardiovascular activity, causes nausea and vomiting
	b. Morphine	Extracted from Opium	Suppress brain activity, provide relief from intense pain
	c. Heroin	Synthetic compound from Morphine	Anxiety, fever, chills, painful gastrointestinal disruption
Hallucinogens	a. Lysergenic Acid Diethylamide (LSD)	Synthesized from lysergic acid produced by Argot fungus	Causes chronic psychosis and sever damage to CNS leading to suicide
	b. Mascaline	Obtained from crushed leaves, flowers and stem of Cannabis Sativa	Eye pupils dilate, blood sugar level rises, urination increases, anxiety, psychosis
	c. Hashish
	d. Bhang, Charas, Ganga
Antipsychotics	Chlorpromazine	Synthetic	Act as antipsychosis

“Say No To Drugs”

LEISHMANIA DONOVANI (KALAZAR)

noreply@blogger.com (prem) — Mon, 26 Jul 2010 05:04:00 +0000

LEISHMANIA DONOVANI (KALAZAR)

Leishmania is a major pathogenic flagellate protozoan parasite found in reticulo- endothelial system (liver, spleen, bone marrow) of human. It causes a serious disease called visceral leishmsaniasis, commonly known as kala-azar or dum dum fever.

History

It is named after the discoverers, Leishman and Donovan, both of them reported the organism simultaneously; Leishman from London in May 1903 and Donovan from Madras of India in July 1903. Sir William Leishman in 1900 observed the parasite in spleen smear of a soldier who died of "Dum dum fever" or kala-azar contracted at Dum Dum, Calcutta. Leishman reported this finding from London in 1903. Donovan also reported the same parasite in spleen smear of patient in Madras.

Distribution

It is endemic in many places in China, India, Africa, Southern Europe, South America and Russia. It is also reported from Nepal.

Habitat

The natural habitat of L. Donovani in man reticulo-endothelial system such internal organs especially spleen, liver, bone marrow, lymphnodes. The parasite may be found in endothelial cells of the kidney, suprarenal capsules, lungs, meninges and cerebrospinal fluid. It is transmitted through biting of sand fly.

Lifecycle of Leishmania in man

L.donovani is transmitted by the sand fly (Phlebotomus argentipes). When an infected sandfly bites a healthy person, promagstigote forms of parasites are introduced in blood.

These promagstigote forms develop into amagstigote forms which reach to the cells of reticulo-endothelial system and multiply by binary fission. Multiplication goes on continuously till the cell becomes packed with the parasites. The reticulo-endothelial cells enlarge and enventually ruptured. The parasites liberated as a result of the rupture into the blood circulation are again either taken up by sandfly or invade fresh cells and the cycle is repeated. In this way the entire reticulo-endothelial system becomes progressively infected.

Method of transmission
The transmission of L.donovani from one person to the other person is carried out by a species of sand fly of the genera Phelebotomus argentipes through biting.

Incubation period
Incubation is long, from 3 to 6 months, and symptoms may appear even after 2 years.

Pathogenesis
It causes a dreadful disease visceral leishmaniasis or kalazar or black fever. Early symptoms of kala-azar include swelling and enlargement of spleen and liver. It is followed by high fever, general weakness, emaciation, anaemia due to reduction in number of blood cells, and a peculiar darkening of skin. The word "kala-azar" has been derived from two Indian words, kala and azar, meaning "black sickness". The clinical illness begins with fever, which may be continuous, remittent or irregular. The spleen is the organ most affected. The enlargement of spleen (splenomegaly) starts early and is progressive and massive.

Diagnosis
Kala-azar can be diagnosed by microscopical examination of blood film or biopsy material taken from spleen or bone marrow of patient, for the presence of amastigote forms of L. donovani. Examination of W.B.C. count shows decrease of neutrophils but increase of lymphocytes and monocytes. Number of erythrocytes (R.B.C.) is also decreased.

Treatment
Pentavalent antimony compounds are the drugs used for the treatment of Kala-azar. Antimony compounds are stibamine, aminostiburea, neostibosan, neostam, and sodium-antimony-gluconate. However, antimony resistance has become a serious problem. The aminoglycoside antibiotic aminosidine (Paromomycin) is useful.

Preventive measures

- Treat all human cases harbouring L. donovani adequately with antimony.

- Eradiction of sandfly by periodic fumigation and spray of insecticides.

- Avoiding bite of sandfly by using mosquito nets.

- Avoid houses surrounded by dense vegetation.

Other related species of Leishmania

· L. tropica – found central and south America, cause muco-cutaneous leishmaniasis.

· L. brasilensis – found in Arabia, Syberia, shores of Mediterranean, cause cutaneous leishmaniasis or oriental sore.

STATUS OF HIV AND AIDS IN NEPAL

noreply@blogger.com (prem) — Sat, 24 Jul 2010 10:31:00 +0000

STATUS OF HIV AND AIDS IN NEPAL

AIDS (Acquired Immune Deficiency Syndrome) is one of the most serious communicable diseases of present day, caused by a HIV (Human Immune deficiency Virus). It affects the immune system and makes the patients unable to defend against any type of infections.

The Red ribbon is a symbol for solidarity with HIV-positive people and those living with AIDS.

T4 lymphocytes are the cells that are responsible for development of immune system in human. AIDS is a disorder which impairs the body’s T4 lymphocytes cells’ immune system. Thus, these T4 lymphocytes cell can no longer help to induce other T cells, called Killers. The body’s immune system breaks down leaving the patient exposed to a variety of diseases. Hence, AIDS is considered as a very dangerous and fatal disease.

Origin of AIDS

AIDS is thought to have originated somewhere in Central Africa, possibly sharing an ancestor with a virus found in several species of African monkey. The virus then appears to have migrated to Haiti and then to USA, and has subsequently been identified from almost all countries throughout the world. It has already infected an estimated in million people. In Nepal, first case was diagnosed in 1988. Now, approximately 50,000 people are suffering from AIDS in Nepal.

AIDS was first reported on June 5, 1981 when the UD centers for Disease Control and Prevention recorded a cluster of Pneumocystis Carinii Pneumonia (now still classified as PCP but known to be caused by Pneumocystis Jirovecii) in five homosexual men in Los Angeles.

Three of the earliest known instances of HIV infection are:

A plasma sample taken in 1959 from an adult male, living in what is now the Democratic Republic of Congo.
HIV found in tissue samples from the 15 years old African-American teenagers who died in St. Louis in 1969.
HIV found in tissue samples from a Norwegian sailor who died around 1976.

Two species of HIV infect humans: HIV-1 and HIV-2. HIV-1 is more virulent and more easily transmitted, originated from the Central Common Chimpanzee (Pan Troglodytes Troglodytes) found in Southern Cameroon. HIV-2 is not as easily transmitted and is largely confined to West Africa, originated from the Sooty Mangabey (Cercocebusatyn), an old world monkey of Guinea Bissau, Gibbon, and Cameroon.

Causative Agent

AIDS was first recognized in the USA in 1981. Doctors reported a number of deaths which were associated with a breakdown of the body’s immune system.

HIV Virus

In 1983, a French physician Dr. Luc Montagnier identified the virus in the lymph nodes of a male homosexual. He termed the virus Lymphadenopathy Virus or LAV. In Britain, Abraham Karpas working at Cambridge University also isolated the virus (C-LAV) from an AIDS patient.

Shortly after-wards Dr. Robert Gallo, National Cancer Research Institute of USA isolated an almost identical virus which he called ‘Human T cell Lymphotropic Virus’ or HTLV-III.

These viruses are all essentially the same, and now the virus is internationally known as the ‘Human Immune deficiency Virus’, symbol being HIV. It is an RNA virus.

Infection by HIV

AIDS is the most severe acceleration of infection with HIV. HIV is a retrovirus that primarily infects vital organs of the human immune system such as CD4+T cells (a subset of T cells), macrophages and dendritic cells. It directly and indirectly destroys CD4+T cells. CD4+T cells are required for the proper functioning of the immune system. When HIV kills CD4+T cells so that there are fewer than 200 CD4+T cells per microliter (µL) of blood, cellular immunity is lost, leading to the condition known as AIDS. Acute HIV infection progresses over time to clinical latent HIV infection and then to early symptomatic HIV infection and later to AIDS, which is identified on the basis of the amount of CD4+1 cells in the blood and the presence of certain infections. In absence of antiretroviral therapy, the median time of progression from HIV infection to AIDS is nine to ten years, and the median survival time after developing AIDS is only 9.2 months. However, the rate of clinical disease progression varies widely between individuals, from two weeks up to 20 years. Many factors affect the rate progression. These include factors that influence the body’s ability to defend against HIV such as the infected person’s general immune function. Older people have weaker immune systems, and therefore have a greater risk of rapid disease progression than younger people. Poor access to health care and the existence of coexisting infections such as tuberculosis also may be predispose people to faster disease progression. The infected person’s genetic inheritance plays an important role and some people are resistant to certain strains of HIV. An example of this is people with CCR5-32 mutation are resistant to infection with certain strains of HIV. HIV is genetically variable and exists as different strains, which cause different rates of clinical disease progression. The use of highly active antiretroviral therapy prolongs both the median time of progression to AIDS and the median survival time.

According to WHO, the infection of HIV has following steps:

Stage I : HIV infection is asymptomatic and not categorized as AIDS.

Stage II : includes minor mucocutaneous manifestations and recurrent upper respiratory tract infections.

Stage III : includes unexplained chronic diarrhea for longer than a month, severe bacterial infections and pulmonary tuberculosis.

Stage IV : includes toxoplasmasis of the brain, candidiasis of the oesophagus, trachea, bronchi or lungs and kaposi’s sarcoma; these diseases are indicators of AIDS.

Transmission

According to WHO, the major transmitting agents are as following and the data alongside is of the number of people per (20000):

Blood Transfusion 9,000

Childbirth 2,500

Needle-sharing injection drug use 67

Receptive anal intercourse 50

Percutaneous needle stick 30

Receptive penile-vagical intercourse 10

Insertive anal intercourse 6.5

Insertive penile-vaginal intercourse 5

Receptive oral intercourse 1

Insertive oral intercourse 0.5

As the above data states, the three main transmission routes of HIV are sexual contact, exposure to infected body fluids or tissues, and from mother to foetus or child during perinatal period. It is possible to find HIV in the saliva, tears, and urine of infected individuals, but there are no recorded cases of infection by these secretions, and the risk of infection is negligible.

1. Intimate sexual contact

The majority of HIV infections are acquired through unprotected sexual relations between partners, one of whom was HIV. Heterosexual intercourse is the primary mode of HIV infection worldwide. Sexual transmission occurs with the contact between sexual secretions of one partner with the rectal, genital or oval mucous membranes of another. Unprotected receptive sexual acts are riskier than unprotective insertive sexual acts, with the risk for transmitting HIV from an infected partner to an uninfected partner through unprotected anal intercourse greater than the risk for transmission through vaginal intercourse or oral sex. Oral sex is not without its risk as HIV is transmissible through both insertive and receptive oral sex. The risk of HIV transmission from exposure to saliva is considerably smaller than the risk from exposure to semen; contrary to popular belief, one would have to swallow gallons of saliva from a carrier to seen a significant risk of becoming infected.

Approximately 30% of women in ten countries representing “diverse cultural, geographical and urban/rural setting” report that their first sexual experience was forced or coerced, making sexual violence a key driver of the HIV/AIDS pandemic. Sexual assault greatly increases the risk of HIV transmission as protection is rarely employed and physical trauma to the vaginal cavity frequently occurs which facilitates the transmission of HIV.

2. Infected blood entering the bloodstream

a) AIDS can also be contracted by intravenous drug users practicing self-injection by means of unsterilized needles and syringes. HIV has spread rapidly amongst intravenous drug users.

b) Transfusion or donating blood infected with HIV can also infect the recipient.

c) Close contact between infected and non-infected people through cuts and open wounds has also been known to pass on the virus.

d) An infected pregnant woman can pass on the virus to her baby through the placenta, at birth or through breast milk during sucking, called MTCT (Mother-To-Child-Transmission). Chance of infection being transmitted from mother to her baby is estimated to be 25.20%.

Incubation Period

Incubation period varies from few months to 6 years or more.

Symptoms (ARC – AIDS Related Complex)

A person with AIDS Related Complex has illness caused by damage to the immune system, but without the opportunistic infections and cancer associated with AIDS. They exhibit one or more of the following clinical features:

i> Unexplained diarrhea for more than a month

ii> Malaise, fatigue, fever for more than a month and night sweats

iii> Weight loss of more than 10% of the body weight

iv> Lymphadenopathy (lymph node enlargement) and splenomegaly (Spleen Swelling)

v> Septicaemia (Blood Poisoning)

AIDS is the end stage of HIV infection. Death is due to uncontrolled or untreatable infection. The severe form of features described under ARC:

i> Kaposi Sarcoma – a type of tumor of skin and mucous membranes

ii> Cytomegalovirus Retinitis – inflammation of retina may lead to blindness

iii> Pneumonia and hairy leukoplakia

iv> Cryptococcal Meningitis

v> Preeritic Desmatitis and Recurrent skin infections

Test for the disease

Blood test is used to tell whether or not a person has been infected by AIDS virus. Blood of a person can be tested with HIV proteins which have been commercially prepared.

If there are anti-HIV antibodies in the blood sample, they will bind to the viral protein. This union of antibody to HIV protein indicates that the blood is from infected person who is then designated HIV+. However, if the test proves negative that person may still be infected. Sophisticated technique being used for detection of anti-HIV antibodies in human blood is ELISA (Enzyme Linked Immuno- Sorvbent Assay).

Control

Enormous international efforts are being made to devise methods of treating and preventing the disease. There are two lines of research, one into developing drugs and another into developing a vaccine. Azidothymidine (AZT) or Zidovudine, Ribavarian, Sumarin, and antiparasitic drug are used to treat other viral infection which has been found to suppress the AIDS virus under laboratory conditions and slow progression of the disease.

Other antiviral agents like Didonosine (DDS) and Zalcitabine are used to prolong life and to increase the quality of life.

HIV/AIDS in Nepal

Nepal is facing increases in HIV prevalence among high risk groups such as sex workers, injecting drug users, men who have sex with men, and migrants. In addition, injecting drug use appears to significantly overlap with commercial sex. There is an urgent need to scale up effective interventions, especially among IDUs. The first case of AIDS in Nepal was reported in 1988. Since then the numbers have risen among the country’s 27 million people. By the end of 2005, more than 950 cases of AIDS and over 5,800 cases of HIV infection were officially reported, with three times as many men reported to be infected as women. However, given the limitations of Nepal’s public health surveillance system, the actual number of infections is expected to be much higher. UN AIDS estimates that 75,000 people were living with HIV at the end of 2005.

Present Status of AIDS in Nepal

Number of children with HIV : 75,000 (2005)

Rate of infected adults (15-49) : 0.5% (2005)

Number of women infected from HIV (15+) : 16,000 (2005)

Deaths due to HIV/AIDS : 19 (2005)

(per 100,000 populations per year)

Deaths due to tuberculosis among HIV+ people : 1 (2005)

Deaths among children under five years of age : 0.2 (2000)

due to HIV/AIDS (%)

Deaths due to HIV in adult and children : 5100 (2005)

HIV in injecting drug users : 50% (2002)

HIV in female sex workers : 2% (2005)

As we can see from the above data that the number of infection and death in Nepal due to HIV is also high and it is increasing. So, all of us should be aware of it.

Prevention

i> Sex education

ii> Screening before blood transfusion

iii> Use of condoms

iv> Rehabilitation of drug addicts

v> Early diagnosis and treatment of other sexually transmitted diseases

Many other preventive measures can be used but the main thing is the awareness.

AIDS do not transmit by

1. Kissing

2. Hugging

3. Shaking hands

4. Using the same thing (towel, toilet)

5. Eating in same place

Control of Alcoholism

noreply@blogger.com (prem) — Thu, 22 Jul 2010 08:12:00 +0000

Control of AlcoholismThe term alcohol generally refers to Ethyl Alcohol (C2H5O6). It is commonly consumed and is obtained through the fermentation of various food particles (e.g. potato, molasses, grains, fruit juices) by organisms like yeast and some fungi. It is the drug found in beer, wine, liquor and in certain other beverages.

The stage where an individual tends to continue excessive or compulsive use of alcoholic drinks and becomes an addict to alcohol is called Alcoholism. It impairs psychological, physiological and socio-economic conditions of the addict. Therefore, alcoholic addiction is considered a sort of disease. Alcohol abuse is not alcoholism but people who abuse alcohol negatively affect themselves and their close ones because of their drinking.

Causes of Alcoholism

A genetically inherited predisposition for alcoholism
As a part of religious or social traditions
Relief from pain
Social pressure
Depression, Anxiety, Stress, etc.
Curiosity
Desire of excitements

Symptoms of Alcoholism

Visual problems like blurred vision, double vision and improper of distance.
Feeling of relaxation and warmth.
Decreased reaction time, Lack of judgment.
Increases the blood pressure and lowers the sugar level.
In women, it particularly affects the ovulation and menstrual cycle.

Effects of Alcoholic drink

1. Effects on the user

It causes anesthetic effect on nervous system.
Prolonged, heavy use of alcohol causes increased secretion of gastric juices that cause inflammation of gastric mucosa leading to gastritis.
It can lead to permanent damage to vital organs viz, the brain and lives.
It lowers the blood sugar level.
It interferes the normal functions of nephrons of kidney.
Alcoholic fats are deposited on the walls of the blood vessels and thus increase the blood pressure and adversely affect the functions of heart.
Infants of the women who drink during pregnancy may suffer from Fetal Alcohol Syndromes (FAS), causing physical and mental disabilities.

2. Effects on family

Loss of money spends on expensive alcohol leading to economic crisis or poverty.
Alcoholism causes domestic problems including divorce.
Children suffer from frustration, anxiety and insecurity.
The prestige of the family will decrease.

3. Effects on community

Increase in road and industrial accidents, crimes like corruption, rapes etc.
Loss of social reputations and personality.
Loss of manpower due to injuries from falls, fights, burns and immature death.

Control of Alcoholism

Early detection and proper treatment of sick persons.
Productions and selling of alcohol should be prohibited.
Strictly implementation of law against anti-social elements and activities.
Providing school education, community and health education.
Rehabilitation.
Psychological treatments.

According to recent data, about 750,000 teens are alcoholic. Moreover, more than 200,000 people die of alcohol related diseases each year. So,

“Alcoholism has these any bad effects so why to drink alcohol, better use the money in other works than in Alcohol.”

“STOP ALCOHOLISM”

Treatment of Ascariasis

noreply@blogger.com (prem) — Wed, 21 Jul 2010 09:41:00 +0000

Treatment of Ascariasis

Ascariasis (as-kuh-Ri-uh-sis) is a type of roundworm infection. Roundworms are parasites that use your body as a host to stay alive and reproduce, maturing from eggs to adult worms inside your body. Eggs of the ascaris roundworm are microscopic, but adult worms are the largest of the intestinal roundworms, reaching lengths up to 16 inches (41 centimeters).

Ascariasis is one of the most common roundworm infections in humans, infecting approximately 25 percent of the world’s population. The highest rate of ascariasis infection occurs in places in which sanitation and hygiene are poor. In the United States, ascariasis is the most common in rural areas with warm climates.

Most of the time, ascariasis causes no symptoms or only mild digestive problems but when your body is infested with hundreds of worms, more serious symptoms and complications can occur.

Ascariasis is an intestinal communicable disease caused by an intestinal parasite known as Ascaris lumbricoides. The adult worm lives in the lumen of the small intestine (jejunum) of man.

Mode of infection

Mode of transmission is feco-oral. Embryonated egg is the infective stage. Infection is effected by swallowing of matured embryonated eggs along with raw vegetables. Infection may occur by drinking contaminated water. Dirty or contaminated fingers may be a possible source of infection.

Incubation period

The incubation period is quite variable from few weeks to months.

Pathogenicity (symptoms)

The disease caused by the infection of A. Lumbricoides in man is known ascariasis. Symptoms caused by Ascaris infection are:

1. Indigestion, abdominal discomfort

2. Acute colic pain

3. Appendicitis, gastric ulcers

4. Diarrhea and vomiting and mild temperature

5. Loss of weight

6. Person becomes weak and anemic

Pathogenicity (symptoms)

The disease caused by the infection of A. Lumbricoides in man is known ascariasis. Symptoms caused by Ascaris infection are:

1. Indigestion, abdominal discomfort

2. Acute colic pain

3. Appendicitis, gastric ulcers

4. Diarrhea and vomiting and mild temperature

5. Loss of weight

6. Person becomes weak and anemic

Treatment

It is treated with anti-helminth drugs such as piperazine, Mebendazole, Albendazole, etc.

Prophylaxis (Prevention)

1. Proper disposal of human faeces

2. Avoid using raw materials and contaminated water

3. Treatment of parasitized individuals and

4. Education of children in schools on sanitary laws and hygiene

5. It is treated with anti-helminth drugs such as piperazine, Mebendazole, Albendazole, etc.

Catfish -The nocturnal scavengers

noreply@blogger.com (prem) — Sun, 18 Jul 2010 06:05:00 +0000

Catfish -The nocturnal scavengers

Catfish is a common name for about 2200 species of fishes, out of which about 1200 are South American. Among them, two families are primarily marine and rest are fresh water. Catfishes are mostly nocturnal scavengers, living near the bottom in swallow waters.

The name catfish is derived from the feelers, or barbels, that extend from each side of the upper jaw of the fish and, in some species, from the lower jaw also, suggesting the whiskers of a cat. The dorsal and pectoral fins are often edged with sharp spines, in some cases poisonous ,that are used in defense and can inflict severe wounds.Members of several catfish families in South America are covered with bony plates. A European species, the sheatfish, or wels, is the largest catfish, reportedly reaching a weight of 290 kg and a length of almost 4m.

The blind catfish, found in caverns in eastern Pennsylvania, has atrophied eyes, and the electric catfish of the Nile River and tropical central Africa is capable of giving an electric shock.Another odd catfish, the so-called walking catfish, originally occurred in eastern India and Southeast Asia. In 1968, it was discovered near Boca Raton, Florida, following its import by tropical-fish dealers. Its maximum length is 56cm. In "walking" to areas of deeper water in dry spells, this catfish moves across land by a slithering motion combined with a thrashing of its tail. In addition, a stout spine in each pectoral fin digs into the ground to help balance and propel the fish. It is able to breathe air by means of a modified gill arch that forms an air chamber.

Of the numerous species of North American catfishes, the bullhead is commonly fished for eating . Of greatest commercial importance are fishes in the Mississippi river valley and the Gulf states, some of which weigh as much as 70kg. The blue catfish, or chuckle head, and the canned catfish , the flesh of which is esteemed as equal to that of black bass, form the major part of the harvest.

Ozone layer and its depletion

noreply@blogger.com (prem) — Thu, 15 Jul 2010 05:19:00 +0000

Ozone layer and its depletion

Ozone layer is the layer of ozone gas formed in the stratosphere between 12 to 24 Km from the surface of the earth. Ozone is formed naturally as oxygen molecules absorb the high energy ultra violet rays of the Sun. The u.v. radiation splits oxygen molecules into oxygen atom which then combine with oxygen molecules to form ozone. The ozone formed absorbs the harmful u.v rays of the sun and protects us from its damaging effects.Due to the absorption of ultraviolet rays, stratosphere has more temperature at upper surface. Ozone layer plays a vital role in the balance of weather and temperature on the earth.

Ozone layer depletion is the burning issue of present days.The ozone layer depletion is the thinning of the ozone layer due to the influence of other gases like chlorofluorocarbons, oxides of nitrogen, carbon monoxide, carbon dioxide, etc. In 1985,NASA scientists discovered a hole in the protective ozone layer over Antarctica. It is believed that the ozone layer began to lose its balance from the decade of seventy. When the gases like CFCs,CO, Oxides of nitrogen, etc. reach into stratosphere, they decompose by ultraviolet radiation and form chlorine.

Due to the ozone layer depletion there has been rise of many problems and imbalance in the environment. Some major effects of the ozone layer depletion are as under.

Effects on human beings
Effects on other animals
Effects on plants
Global warming

Effects on human beings

The ozone layer depletion has an adverse effect on the human being. Due to ozone depletion, the ultraviolet rays fall directly on the earth's surface that causes skin infections, inflammation,different types of cancer, cataract, loss of immunity, etc.It may also effect on DNA which may causes mutation.There are many environmental effects on human directly and indirectly due to ozone layer depletion.

Effects on other animals

The ozone layer depletion has also adverse effects on the animals. Larvae and eggs of aquatic animals and amphibians die due to ozone layer depletion.Ultraviolet rays of the sun also effects fertility of animals which effect their population. The ozone layer depletion can also cayse cancer to the animals.

Effects on plants

The ozone layer depletion leads to the environment change due to which it reduces forests and decreases the crop yielding. Many plants and forests are badly affected due to ozone layer depletion because of harmful ultraviolet rays of sun. It also effect the fertility of field and decreases the crop-yielding.

Global warming

The gases which lead to the depletion of ozone layer is the green house gases like CFCs, carbon monoxides, oxides of nitrogen etc. Due to over green house effect, the temperature of the earth increases, which causes global warming.It is believed that if the temperature of earth continues to increase in the present ratio, the day is not so far, when the oceans will engulf number of islands. There are many environmental, health, economical, developmental effects of ozone layer depletion that we should suffer in coming days.Hence, it is very important for us to protect the ozone layer from depletion.

The following methods should be used for the conservation of ozone layer.

The green house gases that are responsible for depletion of ozone layer like CFCs, carbon monoxides, oxides of nitrogen, etc.should be banned to use as far as possible,
Vehicles in the cities conducted by fossils fuels should be replaced by the vehicles conducted by electricity.
Use of nitrogenous fertilizers should be reduced.
Filter of green house gases should be used in vehicles.It controls their mixing in atmosphere.
People should be aware about the consequences of ozone layer depletion.

Characteristic of enzymes

noreply@blogger.com (prem) — Wed, 14 Jul 2010 05:07:00 +0000

Characteristic of enzymes

Enzymes are the complex organic compounds which are produced by living plants and animals.Enzymes are the chemicals catalysts that control all biochemical reactions in every living thing, from viruses to man. Breathing, digestion, heart action, formation of body tissues, movement of all muscles all these and many more depend on enzymes. So without enzymes these is no life.

Enzymes are protein molecules which act as catalysts to speed up organic reactions in living cells. They are non-living complex nitrogenous compounds produced by living organisms. More than 100,000 different types of enzymes have been identified most of which are colorless solids, soluble in water or dilute solutions, but some are blue, green or greenish brown. Some common enzymes and their specific functions are as follows

Amylase hydrolysis starch into glucose.

Maltase hydrolysis maltose into glucose.

Lactase hydrolysis lactose into glucose and galactose.

Invertase hydrolysis sucrose into glucose and fructose.

Pepsin hydrolysis proteins into amino acids.

Zymase converts glucose into ethanol.

Urease hydrolysis urea into ammonia.

Each enzyme is produced in a particular living cell to catalyze a reaction occurring in that cell.They are the globular proteins which can catalyze various biochemical reactions occurring in the living system. Thus, enzymes are the biological catalysts.

Important characteristics of enzyme catalysis:

Most of the enzymes are proteins of high molecular weight which from colloidal solutions in water.
Extremely small amounts of enzymes are able to bring about measurable changes.
Enzymes are associated with every Chemical reaction that occurs in the living system.
Enzymes generally accelerate biochemical reactions by reducing the energy requirement (activation energy)
Enzymes do not alter the amount or nature of the product.
Enzymes do not affect the amount of energy released or absorbed during the reaction.
Enzymes retain their identity at the end of the reaction ,as in the beginning .
Enzymes are highly specific in their action i.e. each enzyme catalyzes only specific type of reaction.
Enzymes can function at moderate temperature and pH range available in the living system . They lose their catalytic activity at high temperature or in strongly acidic or in alkaline medium.
Catalytic activity of enzymes is greatly enhanced by the presence of activations or co enzymes . These co enzymes may be metal ions (Na+, Mn++, Cu2+etc) or some other smaller Organic molecule (Vitamins etc).

The deficiency of enzymes in our body can cause few diseases. For example, diseases albinism is caused due to the deficiency of enzyme tyrosinase Phenylketone Urea is caused due to the deficiency of enzyme Phenyl alanine hydroxylase.

Energy Scenario of Nepal

noreply@blogger.com (prem) — Mon, 12 Jul 2010 05:55:00 +0000

Energy Scenario of Nepal

Nepal is a small country. It is beautiful and rich in hydroelectric energy. Except Brazil, Nepal is second in world to have high potential of hydroelectricity. Besides, hydroelectricity energy ; the energy demand of Nepal is fulfilled by fossil fuels, wood , dung cake , solar energy etc.

The chief source of energy in Nepal is hydroelectricity. Nepal has a capacity of hydroelectric potential of 83000MW and economically feasible potential is 42000MW. The energy demand in Nepal is met from a combination of traditional and commercial sources such as fuel wood, agriculture residues, animal waste , solar power , hydro power , etc. An authorized survey reports (1995/96) that about 92% of the total energy consumption in Nepal is met by wood ,biomass,and dung cake . Out of this wood alone covers 69%, dung cake covers 8% and other biomass covers 15% of the total energy consumption . In addition to the wood, the dung cake and the biomass ,some people in city areas use biogas such as methane for cooking and lighting .
Though hydroelectricity energy is the most potential source of energy in Nepal , it has not been used sufficiently. However , at present time the use of hydro power energy has increased drastically . Out of total population only about 15% has been major source of energy and about 70% of the total population met their energy demand from forest products.

Nepal also depends on imported fossil fuels . Petroleum exploration is continued to identify its good reserve and a few potential sites of natural gas have been identified . For example, Kathmandu valley is known to have a reserve of Nepal natural gases . The solar and wind energy Many villages of Nepal are dependent upon the solar energy for cooking and lighting. However, wind energy has not been yet used commercially .There are about four solar station in Nepal operated in limited scale in Mugu, Humla , Sindhupalchowk and Tanahu districts . Biogas has become an important alternative energy source with potential production about 1-200 million cubic meter annually . It is also used as one of the dependable alternative source of energy in rural areas . Biogas development is promoted by government and NGO sectors . Many biogas plants have been established under the loan investment of Agriculture development bank. Biogas generation and its use is gaining important in Terai and the valleys.

The present scenario of energy supply and development in the country depicts an unbalanced picture. On an average annual energy consumption scenario is approximately 92% fuel wood including biomass , 7% fossil fuel and 1% electricity . There are significant differences in the trend of utilization in different sources of energy. Commercial energy consumption has grown in comparison to traditional fuels . Heavy dependence on firewood coupled with the high population growth rate is exerting a continuous pressure on forests. Development of the hydro power within government and the supply. Nowadays , there are establishment of many micro hydroelectric power stations, solar stations, etc. which have help to generate surplus power and will reduce people's dependence on forests . The easy policy of government encouraged Private and Foreign sectors to invest in such huge power stations.

Proteins and denaturation of proteins

noreply@blogger.com (prem) — Wed, 07 Jul 2010 06:08:00 +0000

Proteins and denaturation of proteins

Proteins are the polypeptides. They are the long chain polymer of alpha amino acids. Proteins undergo hydrolysis to give alpha amino acids. Proteins are present in muscles, skin, hair, and other tissue that make up the body's non body structure.

Animal proteins: Meat,fish, eggs, milk, cheese, etc.

Vegetable proteins: Pulses, nuts, bean, wheat, fruits, vegetables, etc.

Proteins are nitrogenous organic compounds of high molecular weights synthesized by plants and animals which on hydrolysis by enzymes give amino acids. Their molecular weights range from 6,000 to 1,000,000. Chemically, proteins are polymeric amides, derived from alpha amino acids.
On the basis of molecular structure, proteins are broadly classified into two categories.
a) Fibrous proteins

b) Globular proteins

Fibrous proteins have either long, coiled threadlike structure or sheet type structure. They are usually insoluble in water. Hair, hoofs, skin, nails, silk, animal tissues and wool are the examples of fibrous proteins.

The globular proteins, on the other hand, have their coils looped, twisted and folded so as to have a sphere like compacts structure. Globular proteins are soluble in water and dilute aqueous solutions of acids, bases and salts. Examples of globular proteins are the white of raw egg, blood serum, haemoglobin. Enzymes are also globular proteins.

Functions of proteins
The important role played by proteins in living cells are as follows.

i) As enzymes, they catalyze biological reactions.
ii) As hormones, they regulate metabolic processes.
iii) They serves as the chief structural material of animal tissues.
iv) In the form of antibodies, some proteins have protective and defensive function.
v) Some proteins serve as transport agents to carry oxygen, metals, fatty acids,hormones in the body, eg: Haemoglobin transports oxygen from lungs to all the parts of the bodies.
vi) Proteins act as a source of amino acid in a growing embryo.

Denaturation of proteins

The most stable state of a protein is called its native state or native form.Under certain conditions the arrangement of polypeptide chains within a protein molecule is changed from native form to a disordered arrangement.

The process which leads to the changes in the physical and biological properties of proteins without affecting its chemical composition is called denaturation of proteins.

Kauzmann, in 1959 proposed the term denaturation of protein. Thus during denaturation, only primary structure of the protein is retained. Physical and chemical properties of such proteins are different than the native proteins and they lose most of their biological activities. During denaturation, the soluble globular proteins are changed into insoluble fibrous proteins.
There are several chemicals which can denature the proteins. Minerals acids and alkalis, acetone, alcohols, salts, such as ammonium sulphate , urea, picric and trichloro acetic acids are common denaturing chemicals. Hydrostatic pressure, ultraviolet and ionizing radiations also cause denaturation.
The most common examples of the denaturation of proteins are:
i) Boiling of egg.
Boiling of an egg involves coagulation of the albumin present in the white of egg.
When an egg is boiled in water, the soluble globular proteins in the white of egg get converted into insoluble fibrous proteins.
ii) Preparation of cheese from milk.
When milk is heated with an acid (lemon juice) formation of cheese takes place. During this denaturation, the globular milk protein, lacto albumin becomes fibrous.

Tuberculosis and its treatment

noreply@blogger.com (prem) — Wed, 07 Jul 2010 05:40:00 +0000

Tuberculosis and its treatment

Tuberculosis (TB) is a contagious, wasting disease characterized by the coughing up of mucus and sputum, fever, weight loss, and chest pain. It is a bacterial infection caused by a germ called Mycobacterium tuberculosis.

It was first isolated in 1882 by a German physician named Robert Koch who received the Nobel prize for this discovery. TB most commonly affects the lungs but also can involve almost any organ of the body like central nervous system, lymphatic system, circulatory system, genitourinary system, joints and bones.

Symptoms

When the disease becomes active, 75% of the cases are pulmonary TB:

The individual may get tired easily, feel slightly feverish or cough frequently .
Chest pain, coughing up blood, and a productive, prolonged cough for more than three weeks .
Systemic symptoms include fever, chills, night sweats, appetite loss, weight loss, pallor, and often a tendency to fatigue very easily Coughing up blood or mucus.
In the other 25% of active cases, the infection moves from the lungs, causing other kinds of TB .
Extrapulmonary infection sites include the pleura, the central nervous system in meningitis, the lymphatic system in scrofula of the neck, the genioturinary system in urogenital tuberculosis, and bones and joints in Pott’s disease of the spine.

Causes

The primary cause of TB, Mycobacterium bacillus, is an aerobic bacterium that divides every 16 to 20 hours.
Tuberculosis spreads by droplet infection when a TB patient exhales, coughs, or sneezes, tiny droplets of fluid containing tubercle bacilli are released into the air .
Only about one in three close contacts of a TB patient, and fewer than 15% of more remote contacts are likely to become infected since it is not that highly contagious.
Unlike many other infections, TB is not passed on by contact with a patient's clothing, bed linens, or dishes and cooking utensils.
The fetus of an infected mother may contract TB by inhaling or swallowing the bacilli in the amniotic fluid.
Tuberculosis is spread through air droplets which are expelled when persons with infectious TB disease cough, sneeze, speak, or sing.

Data and Statistics

Tuberculosis (TB) is one of the world’s deadliest diseases:

One third of the world’s population are infected with TB.
Each year, over 9 million people around the world become sick with TB.
Each year, there are almost 2 million TB-related deaths worldwide.
TB is a leading killer of people who are HIV infected.

Status of Tuberculosis in Nepal

Nepal witnesses 40,000 TB patients additional every year.
Nepal is witnessing 40,000 additional tuberculosis (TB) patients each year, the National News Agency RSS.
According to the report, 5,000 to 7,000 in Nepal are dying of the disease every year, and 45 percent of the total population of Nepal are ailing from the disease.
Tuberculosis is found to have attacked one in every three persons and one in every 10 persons are vulnerable to the disease in the country, the report said.
In the central development region in the country, altogether 3, 963 people, including 1,439 women, were found to have suffered from TB in the current fiscal year 2006/07 ending in mid-July, according to report.

Preventive Measures

Preventive measures includes two parallel approaches, they are identification and treatment

Identification of infections often involves testing high-risk groups for TB.
Children are vaccinated to protect them from TB. (note: vaccines are not available for the adults).
In tropical areas where the levels of other species of mycobacteria are high, exposure to non tuberculous mycobacteria gives some protection against TB .
BCG provides some protection against severe forms of pediatric TB but has been shown to be unreliable against adult pulmonary TB
To use preventive measures as wearing mask before coming in contact to the patient.
In order to encourage further discovery, researchers and policymakers are promoting new economic models of vaccine development including prizes, tax incentives and advance markets commitments.
In addition to these, media can play vital role to eradicate this disease by raising awareness amongst the public.

Hepatitis B and its treatment

noreply@blogger.com (prem) — Wed, 07 Jul 2010 05:18:00 +0000

Hepatitis B and its treatment

Hepatitis B is a disease caused by hepatitis B virus (HBV) which infects the liver of hominoidae, including humans, and causes an inflammation called hepatitis.

Originally known as "serum hepatitis", the disease has caused epidemics in parts of Asia and Africa, and it is endemic in China. About a third of the world's population, more than 2 billion people, have been infected with the hepatitis B virus. This includes 350 million chronic carriers of the virus. Transmission of hepatitis B virus results from exposure to infectious blood or body fluids containing blood.

Symptoms

Incubation period

From 2 weeks to 6 months after viral entry to the liver, during which time a person is extremely contagious
Symptoms disappear over 6-12 months until complete recovery

Hepatitis B symptoms are similar to Hepatitis A but can also include:

Muscle/joint ache
Pain in the abdomen
However, the virus may continue its silent attack on the liver which over a period of years can lead to:
Cirrhosis
scarring of the liver which slows the blood flow through the liver, causing increased pressure in the vein that transports blood from the stomach and the intestines to the liver
Lifelong infection
Varicose veins
esophageal varicies can develop in the stomach and esophagus and these large veins can break without warning, causing a person to vomit blood or have black, tarry stools
Over 5,000 persons die from chronic liver disease caused by the Hepatitis B Virus infection each year including:
Liver cancer
Liver cell damage
Liver failure
Scarring of the liver

Transmission

Hepatitis B is transmitted through:

Blood
Blood sucking arthropods (mainly in the tropics).
Blood transfusions
Contaminated drinking water or ice
Feces
Raw or uncooked shellfish (oysters, clams or mussels)
Saliva
Seminal fluid
Uncooked fruits or vegetables grown with or washed in contaminated water
Urine
Vaginal secretions

Diagnosis

Because of the complexity and the antigenic differences of the virus, there are a number of tests available for Hepatitis B.There are three standard blood tests:

Antigens

HBsAg - presence of the virus
HBcAg - not detected in blood
HBeAg - correlates with the viral replication and infectivity.

Antibodies

Anti-HBs- antibodies to the surface (antibody to HbsAg)
Positive means you are immune to Hepatitis B (from either having had the disease or from having been given the vaccine)
Anti-HBc
Antibodies to the core can be either IgM (acute) or IgG (chronic)
Anti-HBe
Antibodies to 'e' indicating low infection rate and probable recovery

Treatment

There is no medical treatment but an effective vaccination is available.

There are two medications to treat chronic Hepatitis B Virus:-

Interferon (IFN) .
Lamivudine
Less than 50% of patients with chronic Hepatitis.. B Virus (HBV) are suitable for Interferon therapy.
Initially, 40% of Hepatitis B Virus (HBV) patients who are treated with Interferon (IFN) will respond.
Some will relapse when the treatment is stopped.
About 35% of eligible patients will benefit.

Prevention

All individuals living in the same household with a chronically infected individual should be vaccinated against Hepatitis B.
If exposed to hepatitis B, get a Hepatitis B immune globulin ( HBIG) injection within 14 days following exposure.
Individuals with hepatitis C and other chronic liver diseases should receive the Hepatitis B vaccine.
Practice safety measures as for Hepatitis A.
Those who are chronically infected with Hepatitis B virus should be vaccinated against Hepatitis A as well.

Cancer and its treatment

noreply@blogger.com (prem) — Tue, 06 Jul 2010 05:59:00 +0000

Cancer and its treatment

Cancer is the new growth of tissue resulting from a continuous proliferation of abnormal cells that have the ability to invade and destroy other tissues. It is a disease in which cells divide in uncontrolled way. The cells which divide in such way are known as cancerous cells or malignant neoplasm.

The three major sub-types of cancer are :

The first, sarcomas, arise from connective and supportive tissue, such as bone, cartilage, nerve, blood vessels, muscle, and fat.
The second, carcinomas, which include the most frequently occurring forms of human cancer, arise from epithelial tissue, such as the skin and the lining of the body cavities and organs, and glandular tissue, such as that of the breast and prostate.
The third subtype, leukemias and lymphomas, include the cancers that involve blood-forming tissue and are typified by the enlargement of the lymph nodes, the invasion of the spleen and bone marrow, and the overproduction of immature white blood cells.

CAUSES OF CANCER

About 80% of cancers are potentially preventable. The biggest known cause is smoking, which accounts for 30 per cent of deaths from the disease. Although all the causes of cancer are yet to be ascertained, accumulating evidence about the effects of smoking, diet, radiation, hereditary factors, hormones, chemicals, and certain types of infection shows that these factors may be involved.

Smoking:-Smoking is one of the biggest causes of premature death. It causes 90% of lung cancers. It can also cause cancer in a number of other parts of the body, including the mouth, pharynx, larynx, oesophagus, pancreas, renal pelvis, bladder, and cervix.
Diet:- Diet is probably linked to about 30 -35% of cancers. Many researchers believe that it plays a part in many of the most common cancers, such as those of the breast and bowel. However, as yet, there is no concrete proof of which elements can cause cancer and which help to protect against it.
Alcohols:- Over-consumption of alcohol is responsible for 3% of cancer deaths. Cancers of the mouth, throat, and oesophagus are linked to this, with those most at risk being people who drink excessively and smoke cigarettes.
Infections:- There is growing evidence that some infections are linked to certain cancers. In particular, infections have been found to be involved in cancers of the stomach, liver and cervix and —a rare cancer which occurs in AIDS patients.The bacterium Helicobacter pylori may help to cause many cases of stomach cancer. Studies have shown that people infected with the bacterium are four times more likely to develop this cancer.

SYMPTOMS OF CANCER

Persistent cough or hoarseness in a smoker.
Persistent change in digestive and bowel habits.
Rapid change in the form, appearance and growth of a mole or wart.
A hard area in the breast.
Excessive loss of blood during monthly period in women.
A swelling or sore throat that does not heal easily.
Unexpected loss of weight.

TREATMENT

The traditional means of treating cancer have been surgery, radiation, and chemotherapy. However, revolutionary treatments are now under development and researchers are using laboratory discoveries to design drugs that will exploit specific biological processes in cancer.

Surgery: the principal approach to curing cancer is to remove all the malignant cells by a surgical operation. In the past this meant the removal of all of the involved tissue and as much potentially involved tissue as possible, including adjacent tissues and lymph nodes.
Radiation Therapy: Electromagnetic radiation includes gamma rays, which are emitted by radioactive decay, and X-rays, which are produced when a beam of electrons strikes a heavy-metal target. Particulate radiation includes beams of electrons, protons, neutrons, alpha particles and negative pi. Tumours vary greatly in their sensitivity to radiation. When a tumour is readily accessible—into which a radiation source can be introduced—it may be curable by radiation therapy.
Chemotherapy: It is the use of drugs in the treatment of cancer. Since a drug is distributed throughout the body by the bloodstream, chemotherapy is prescribed for tumours that have spread beyond the area accessible by surgery or radiotherapy. A number of different types of anti-cancer drugs are used, but nearly all work by interfering with DNA synthesis or function. Rapidly dividing cells are therefore more sensitive to chemotherapy.
Hormone Therapy: Many cancers arising from tissues that are hormone-dependent, such as the breast, prostate, endometrium (uterine lining), and thyroid, are responsive to hormone manipulation. This may consist of removing the source of the stimulating hormone or the administration of various hormones, antihormones, and hormone blockers, such as tamoxifen.

Prevention

Smoking habit must be stopped.
Chewing of tobacco, bettle should be stopped.
Over exposure to solar-radiation & X-rays should be avoided.
Canned food should not be taken as it is mixed with several antibacterial preservative chemicals.
Avoid obesity. Too much fats & heavy intake of alcohols should be avoided.
Regular medical check-up of the body is must in present age.
Intake of cruciferous vegetables like cauliflower, cabbage, with other food rich in vitamin A and C is very beneficial.
Balanced diet, pollution free environment, proper sanitation enhance the immune power against any disease
Moderate exercise lessens the chance of cancer.

Mercury poisoning and Minamata Epidemic

noreply@blogger.com (prem) — Mon, 05 Jul 2010 05:27:00 +0000

Mercury poisoning and Minamata Epidemic

Mercury is present in nature in trace amount which has adverse negative impact on environment and living creatures.Mercury and its compounds are highly toxic in nature.

The toxicity of mercury compounds depends their solubility.Mercury compounds which are volatile or soluble are potential hazards for human body. But fortunately most of the compounds of mercury are insoluble so do not cause toxicity. Inorganic salts of mercury are not very toxic if swallowed. Most of the salts are excreted unchanged from the body. But organic salts of mercury are more toxic than inorganic salts. Mercury reacts by replacing the two hydrogen atoms in a (-SH) sulfhydry group. The free -SH groups are essential for enzyme activity. When the bond with mercury is formed enzyme becomes inactive. As a result, biological process in cells are disturbed and symptoms of mercury poisoning are seen.

Naturally during volcanic eruption and burning of coal also dispose of mercury in atmosphere takes place. Combustion of coal releases about 5000 tons of mercury in atmosphere every year.

Mercury vapor is very toxic ,if inhaled it passes into blood stream, the digestive system, lungs and the transported to brain. Exposure to methyl mercury compounds can cause brain damage,loss of vision, madness and even death. The symptoms of mercury poisoning are depression, irritability, shaking of hands and psychotic behavior.

In the 19th century, mercuric nitrate and mercuric chloride were used in the production of felt hats. The dust from this factory was a serious occupational hazard to the workers of this factory.The mercury salt affected the central nervous system of workers. The workers suffered from tremors and a physical disturbance due to the mercury poisoning . This gave rise to the phrase "as mad as s hatter" and consequently it was banned.Besides these, industries producing sodium hydroxide and chlorine by electrolysis of brine, some mercury is lost through waste products into river water causing mercury poisoning.

Two major epidemics due to mercury poisoning took place in Japan due to the industrial release of mercury compounds in the Minamata Bay.The industries which manufactured acetaldehyde and PVC in Minamata were using mercury compounds as catalyst and they released their effluents into Minamata Bay. The mercury compounds present in the effluent were converted to organomercury compounds by anaerobic bacteria in the mud in the seabed. Planktons took it up which was eaten up by fish and mercury was accumulated in the fish. The people of Minamata consumed such fish and suffered from fatal diseases known as "Minamata Epidemic" which killed thousands of people, several were affected and many new babies were born with severe birth defects including brain damage.