HUMAN CLONING

HUMAN CLONING

Although genes are recognized as influencing behavior and cognition, "genetically identical" does not mean altogether identical; identical twins, despite being natural human clones with identical DNA, are separate people, with separate experiences and not altogether overlapping personalities. The relationship between an "original" and a clone is rather like that between identical twins raised apart; they share all the same DNA, but little of the same environment. A lively scientific debate on this topic occurred in the journal Nature in 1997.Ultimately, the question of how similar an original and a clone would be boils down to how much of personality is determined by genetics, an area still under active scientific investigation.

TECHNIQUES

The most successful common cloning technique in non-human mammals is the process which produced Dolly the sheep. It is also the technique used by Advanced Cell Technology, the first company to successfully clone a human embryo (see research section below). The process is as follows: an egg cell taken from a donor has its nucleus removed. Another cell with the genetic material to be cloned is fused with the original egg cell. In theory, this process, known as somatic cell nuclear transfer, could be applied to human beings.

In principle, another way of cloning would be by parthenogenesis, where an unfertilized egg cell is induced to divide and grow as if it were fertilized. Even if it were practical with mammals, this technique could work only with females. Discussion of human cloning generally assumes the use of somatic cell nuclear transfer, rather than parthenogenesis.

Claims of success in human cloning beyond the embryo stage

In 1978 David Rorvik claimed in his book In His Image: The Cloning of a Man that he had personal knowledge of the creation of a human clone. A court case followed. He failed to produce corroborating evidence to back up his claims; now regarded as a hoax.

Severino Antinori made claims in November, 2002 that a project to clone human beings had succeeded, with the first human clone due to be born [in January 2003.] His claims were received with skepticism from many observers.

In December 2002, Clonaid, the medical arm of a religion called Raëlism, who believe that aliens introduced human life on Earth, claimed to have successfully cloned a human being. They claim that aliens taught them how to perform cloning, even though the company has no record of having successfully cloned any previous animal. A spokesperson said an independent agency would prove that the baby, named Evá, is in fact an exact copy of her mother. Shortly thereafter, the testing was cancelled, with the spokesperson claiming the decision would ultimately be left up to Evá's parents.

In December 2004 Dr. Brigitte Boisselier, claimed in a letter to the UN that Clonaid has successfully cloned 13 children, however their identities cannot be revealed to the public in order to protect them.

On October 9, 2003, newspaper Le journal de Montréal published an article accusing Clonaid and the Raelian religion of maintaining an outright hoax in its claims regarding cloning a human baby.

In 2004 a group of scientists led by Hwang Woo-Suk of Seoul National University in South Korea claimed to have grown 30 cloned human embryos to the one-week stage, and then successfully harvested stem cells from them. The results of their experiment were published in the peer-reviewed journal Science.

On May 30, 2005, Hwang's team announced the creation of 11 lines of human stem cells, using a different technique (Hwang et al. 2005). The journal Science later retracted Hwang's publications when investigations into the matter revealed that the claims were fraudulent.

Possible advantages

Human cloning might produce many benefits. Human therapeutic cloning could provide genetically identical cells for regenerative medicine, and tissues and organs for transplantation.Such cells, tissues, and organs would neither trigger an immune response nor require the use of immunosuppressive drugs.[citation needed] Both basic research and therapeutic development for serious diseases such as cancer, heart disease, and diabetes, as well as improvements in burn treatment and reconstructive and cosmetic surgery, are areas that might benefit from such new technology.

Human reproductive cloning also might produce benefits. Antinori and Zavos hope to create a fertility treatment that allows parents who are both infertile to have children with at least some of their DNA in their offspring.

Some scientists, including Dr. Richard Seed, suggest that human cloning might obviate the human aging processHow this might work is not entirely clear since the brain or identity would have to be transferred to a cloned body. Dr. Preston Estep has suggested the terms "replacement cloning" to describe the generation of a clone of a previously living person, and "persistence cloning" to describe the production of a cloned body for the purpose of obviating aging, although he maintains that such procedures currently should be considered science fiction

The current law on human cloning

U.N.

On December 12, 2001 the United Nations General Assembly began elaborating an international convention against the reproductive cloning of human beings. Lawrence S. B. Goldstein, college professor of cellular and molecular medicine at the University of California at San Diego, claims that the United States, unable to pass a national law, forced Costa Rica to start this debate in the UN over the international cloning ban. Unable to reach a consensus on a binding convention, in February 2005 a vaguely worded and non-binding United Nations Declaration on Human Cloning was finally adopted

U.K.

The British government introduced legislation in order to allow licensed therapeutic cloning in a debate in January 2001 after an amendment to the Human Fertilisation & Embryology Act 1990. However on November 15, 2001 a prolife group won a High Court legal challenge that effectively left cloning unregulated in the UK. Their hope was that Parliament would fill this gap by passing prohibitive legislation. The government was quick to pass legislation prohibiting reproductive cloning Human Reproductive Cloning Act 2001. The remaining gap with regard to therapeutic cloning was closed when the appeals courts reversed the previous decision of the High Court. Currently therapeutic cloning is allowed under license from the Human Fertilisation and Embryology Authority. The first licence was granted on August 11, 2004 to researchers at the University of Newcastle to allow them to investigate treatments for diabetes, Parkinson's disease and Alzheimer's disease.

SOURCE: WIKIPEDIA

SPACE SUIT

SPACE SUIT

A space suit is a complex system of garments, equipment and environmental systems designed to keep a person alive and comfortable in the harsh environment of outer space. This applies to extra-vehicular activity (EVA) outside spacecraft orbiting Earth and has applied to walking, and riding the Lunar Rover, on the Moon.

Some of these requirements also apply to pressure suits worn for other specialized tasks, such as high-altitude reconnaissance flight. Above Armstrong's Line (~63,000 ft/~19,000 m), pressurized suits are needed in the sparse atmosphere. Hazmat suits that resemble space suits are also used when dealing with certain types of biological hazard

SPACE SUIT REQUIREMENTS

Several things are needed for the space suit to function properly in space. It must provide:

A stable internal pressure. This can be less than earth's atmosphere, as there is usually no need for the spacesuit to carry nitrogen.

Lower pressure allows for greater mobility, but introduces the requirement of pre-breathing to avoid decompression sickness.

Movement is typically opposed by the pressure of the suit; mobility is achieved by careful joint design.

Breathable oxygen. Circulation of cooled and purified oxygen is controlled by the Primary Life Support System.

Temperature regulation. Heat can only be lost in space by thermal radiation, or conduction with objects in physical contact with the space suit. Since heat is lost very slowly by radiation, temperature is regulated by a Liquid Cooling Garment and heavy insulation on the hands and possibly feet.

Shielding against harmful electromagnetic radiation

Shielding against particle radiation

Protection against micrometeoroids, provided by a Thermal Micrometeoroid Garment, which is the outermost layer of the suit

A communication system

Means to recharge and discharge gases and liquids

Means to maneuver, dock, release, and/or tether onto space craft

Means of collecting and containing solid and liquid waste

OPERATING PRESSURE

Generally, to supply enough oxygen for respiration, a spacesuit using pure oxygen must have a pressure of about 4.7 psi, equal to the 3 psi partial pressure of oxygen in the Earth's atmosphere at sea level, plus 40 torr CO2 and 47 torr water vapor pressure, both of which must be subtracted from the alveolar pressure to get alveolar oxygen partial pressure in 100% oxygen atmospheres, by the alveolar gas equation.The latter two figures add to 87 torr (mm Hg) which is about 1.7 psi, which is why many modern spacesuits don't use 3 psi, but 4.7 psi (this is a slight overcorrection, as alveolar partial pressures at sea level are not a full 3 psi = 155 torr, but a bit less). In spacesuits that use 3 psi, the astronaut gets only 3 - 1.7 = 1.3 psi of oxygen, which is about the alveolar oxygen partial pressure attained at an altitude of 6,100 ft. (1860 m) above sea level. This is about 78% of normal sea level pressure, about the same as pressure in a commercial passenger jet aircraft, and is the realistic lower limit for safe ordinary space suit pressurization which allows reasonable work capacity

REPRESENTATION OF SPACE SUIT WIT IT'S VARIOUS PARTS

COURTESY: WIKIPEDIA

GPRS

General Packet Radio Service(GPRS)

General Packet Radio Service (GPRS) is a Mobile Data Service available to users of Global System for Mobile Communications (GSM) and IS-136 mobile phones. GPRS data transfer is typically charged per megabyte of transferred data, while data communication via traditional circuit switching is billed per minute of connection time, independent of whether the user has actually transferred data or has been in an idle state. GPRS can be used for services such as Wireless Application Protocol (WAP) access, Short Message Service (SMS), Multimedia Messaging Service (MMS), and for Internet communication services such as email and World Wide Web access.

2G cellular systems combined with GPRS is often described as "2.5G", that is, a technology between the second (2G) and third (3G) generations of mobile telephony. It provides moderate speed data transfer, by using unused Time division multiple access (TDMA) channels in for example the GSM system. Originally there was some thought to extend GPRS to cover other standards, but instead those networks are being converted to use the GSM standard, so that GSM is the only kind of network where GPRS is in use. GPRS is integrated into GSM Release 97 and newer releases. It was originally standardized by European Telecommunications Standards Institute (ETSI), but now by the 3rd Generation Partnership Project (3GPP).

Basics

GPRS is packet-switched, which means that multiple users share the same transmission channel, only transmitting when they have data to send. Thus the total available bandwidth can be immediately dedicated to those users who are actually sending at any given moment, providing higher use where users only send or receive data intermittently. Web browsing, receiving e-mails as they arrive and instant messaging are examples of uses that require intermittent data transfers, which benefit from sharing the available bandwidth. By contrast, in the older Circuit Switched Data (CSD) standard included in GSM standards, a connection establishes a circuit, and reserves the full bandwidth of that circuit during the lifetime of the connection.

Usually, GPRS data are billed per kilobyte of information transceived, while circuit-switched data connections are billed per second. The latter is because even when no data are being transferred, the bandwidth is unavailable to other potential users.

The multiple access methods used in GSM with GPRS are based on frequency division duplex (FDD) and FDMA. During a session, a user is assigned to one pair of up-link and down-link frequency channels. This is combined with time domain statistical multiplexing, i.e. packet mode communication, which makes it possible for several users to share the same frequency channel. The packets have constant length, corresponding to a GSM time slot. The down-link uses first-come first-served packet scheduling, while the up-link uses a scheme very similar to reservation ALOHA. This means that slotted Aloha (S-ALOHA) is used for reservation inquiries during a contention phase, and then the actual data is transferred using dynamic TDMA with first-come first-served scheduling.

GPRS originally supported (in theory) Internet Protocol (IP), Point-to-Point Protocol (PPP) and X.25 connections. The last has been typically used for applications like wireless payment terminals, although it has been removed from the standard. X.25 can still be supported over PPP, or even over IP, but doing this requires either a router to perform encapsulation or intelligence built in to the end-device/terminal e.g. UE(User Equipment). In practice, when the mobile built-in browser is used, IPv4 is being utilized. In this mode PPP is often not supported by the mobile phone operator, while IPv6 is not yet popular. But if the mobile is used as a modem to the connected computer, PPP is used to tunnel IP to the phone. This allows DHCP to assign an IP Address and then the use of IPv4 since IP addresses used by mobile equipment tend to be dynamic.

DNA RETROVIRUS

The 3D retrovirus is unique to other viruses in that it carries its genomic information in RNA, not the standard DNA that most do. The retrovirus is somewhat of an oddity in the world of molecular biology. It's name is indicative of why this molecule stands out from other viruses. Most viruses take over their host cells by injecting them with their own viral DNA, which then follows the central dogma of molecular biology to transcribe RNA and translate proteins. What the retrovirus does, however, is inject its own viral RNA into the cell which then encodes the viral DNA to be produced within the host cell. This goes retroactively to the traditional order of DNA to RNA to proteins, hence the name, retrovirus. The retrovirus itself stores its genome on two strands of RNA that eventually injected into the cytosol of the host cell along with enzymes such as reverse transcriptase that initiate the reversed transcription of DNA from the viral RNA. This newly formed DNA is integrated into the genome of the host cell, and is now referred to as a provirus. This reversed transcription lacks "proof-reading" mechanisms otherwise had, and consequently mutations occur frequently in a typical retrovirus. It is for this reason, vaccines against retroviruses-such as HIV-are so difficult to obtain. Not all retroviruses are bad as it may seem. Some insert into human DNA and are passed on to succeeding generations, becoming endogenous retroviruses. These endgenous retrovirus play an important role in protecting the genome against some infections of other harmful retroviruses and even assisting in development during gestation.

COURTESY: 3Dscience.com

A THREE DIMENSIONAL VIEW OF THE HUMAN HEART

COURTESY: 3Dscience.com