Tuesday, January 8, 2008

Panasonic Shows 150-inch Plasma Screen

The Panasonic prototype stretches 11 feet across and may be the largest in the world.

Plasma screens just keep getting bigger, with Panasonic today showing the prototype of a new 150-inch plasma display, which the company says is the largest flat-panel display in the world.

Announcing giant screens is almost a full-time hobby at shows like CES, however.

Measuring 11 feet wide, the Panasonic Life Screen is the size of nine 50-inch plasma screens, said Toshihiro Sakamoto, president of Panasonic AVC Networks Co., during a Monday keynote at the International Consumer Electronics Show in Las Vegas.

It displays images at a resolution of 2160 by 4096 pixels, four times the resolution of Panasonic's current high-definition plasma screens, which display images at a 1080-by-1920 pixel resolution, Sakamoto said.

The 150-inch panel is designed for digital cinema and promotional installations. Sakamoto did not say when the screen would be delivered. In developing the product, Panasonic was encouraged by the sales of 3,000 units of 103-inch plasma TVs, more than the company expected, Sakamoto said.

Other Prototype TVs

The executive also showed off a prototype 50-inch plasma high-definition, thin TV. The display is 24.7 millimeters (0.97 inches) thick and weighs around 22 kilograms (48 pounds), half the weight of current high-definition TV models in similar sizes, Sakamoto said. This makes for easier installation and wall-mounting of the screen.

No shipping date for the 50-inch screen was announced.

Panasonic is making an effort to reduce the power consumption of plasma displays, Sakamoto said, and the new designs include new circuitry and designs that cut energy consumption by up to half.

The International Consumer Electronics Show runs through Jan.10.

Read more coverage of the 2008 CES on PC World.com.


LG Goes Super-Skinny with 60-inch Flat-Panel TV

New at CES: the 45-millimeter LG60 LCD, an ultramobile PC, and mobile broadcasting device.

LAS VEGAS -- South Korea's LG Electronics will later this year launch a 60-inch flat-panel TV that is just 45 millimeters thick, the company is due to announce Sunday at the International Consumer Electronics Show here.

The LG60 LCD is one of a number of thin flat-panel TVs due to be unveiled at CES, which starts officially on Monday. Thin is in this year in the competitive area of the TV market.

Japan's JVC has already announced it will launch LCD TVs in the middle of this year that are 39 millimeters thin and both Hitachi and Sharp are due to show prototype thin sets. Sony and Samsung are also expected to show even thinner TVs based on OLED (organic light emitting display) technology.

Equipped with a number of features including 120Hz scanning, which makes fast moving images appear smoother, and a lighting sensor that automatically adjusts brightness according to the ambient environment, the 60-inch LCD TV also consumes 50 percent less power than current models, LG said in a statement. The company is also planning to unveil a new 60-inch PDP (plasma display panel) TV set that offers a high contrast ratio of 30,000:1.

LG has also updated its 70-inch LCD and PDP sets to include Full HD wireless data streaming.

Also New: Mobile Gear

In addition to the new TVs, LG will also be showing a slider-type Ultra Mobile PC (UMPC). The machine is based on Intel's Menlow platform and comes with 1GB of memory, a 40GB hard disk drive, touchscreen, Bluetooth, WiFi, HSDPA cellular data and a QWERTY keyboard.

On Monday the company is scheduled to demonstrate a new digital TV broadcasting system for mobile and handheld devices. The Mobile Pedestrian Handheld (MPH) system was developed by LG with Zenith and Harris Corp. and is based on existing TV broadcast standards. Unlike the competing DMB, DVB or MediaFlo technologies it does not require TV stations to buy extra frequency spectrum.

The system, which was first shown at the National Association of Broadcasters' convention in April, was tested by several U.S. TV stations last year and will be demonstrated at CES with MPH-enabled cell phones, laptop PCs, portable navigators and in-car TVs.

LG said it anticipates the mobile TV market growing from US$200 million in 2006 to US$4.1 billion in 2010.

See PC World's ongoing coverage of the Consumer Electronics Show at our CES InfoCenter.


Samsung Shows OLED and Quad-HD TVs at CES

Announcements include ultrathin 14- and 31-inch OLED TVs and a prototype with four times the definition of most HD sets.

LAS VEGAS -- Samsung Electronics is unveiling here today two ultrathin TVs and a prototype LCD TV with four times the definition of today's most advanced high-definition sets.

The ultrathin TVs are based on OLED (organic light emitting diode) technology and boast 14-inch and 31-inch screen sizes, the company said in a statement distributed in South Korea. The announcement is part of a preview for the Consumer Electronics Show here.

OLED technology is being fiercely developed by many TV makers because it offers a brighter, more vivid picture than today's LCD panels. And because OLED pixels emit their own light, a backlight isn't required, meaning OLED TVs use less power and are also much thinner.

That thinness was a big contributor to the success of the world's first consumer OLED TV, Sony's XEL-1 set that went on sale in Japan in December and promptly sold-out despite a relatively expensive ¥200,000 (US$1,834) price tag. The Sony set is just 3 millimeters thick, which is less than a tenth that of current LCD TVs.

Samsung previously demonstrated its 14-inch OLED prototype last year but the 31-inch is new. It's also the largest OLED TV panel yet shown by a TV maker so promises to be a star of the International Consumer Electronics Show.

At the show Samsung will also unveil a prototype LCD TV that boasts a resolution of 3,840 pixels by 2,160 pixels -- that's double the vertical and horizontal resolution of a current "Full HD" TV set.

The display is therefore expected to offer a crisper, clearer picture than is possible with today's TVs but could take a while to be commercialized because no broadcasters have concrete plans to launch higher resolution services.

Japan's public broadcaster, NHK, is one of a number of organizations researching next-generation HDTV and has demonstrated many times a "Super Hi-Vision" service that offers an even higher resolution than the Samsung prototype TV. The service has 7,680 pixels by 4,320 pixels and isn't expected to launch commercially until sometime in the next decade.

See PC World's ongoing coverage of the Consumer Electronics Show at the CES InfoCenter.




The importance of mitosis is the maintenance of the chromosomal set; each cell formed receives chromosomes that are alike in composition and equal in number to the chromosomes of the parent cell. Transcription is generally believed to cease during mitosis, but epigenetic mechanisms such as bookmarking function during this stage of the cell cycle to ensure that the "memory" of which genes were active prior to entry into mitosis are transmitted to the daughter cells.[17]

Consequences of errors

Although errors in mitosis are rare, the process may go wrong, especially during early cellular divisions in the zygote. Mitotic errors can be especially dangerous to the organism because future offspring from this parent cell will carry the same disorder.

In non-disjunction, a chromosome may fail to separate during anaphase. One daughter cell will receive both sister chromosomes and the other will receive none. This results in the former cell having three chromosomes coding for the same thing (two sisters and a homologue), a condition known as trisomy, and the latter cell having only one chromosome (the homologous chromosome), a condition known as monosomy. These cells are considered aneuploidic cells and these abnormal cells can cause cancer.[18]

Mitosis is a traumatic process. The cell goes through dramatic changes in ultrastructure, its organelles disintegrate and reform in a matter of hours, and chromosomes are jostled constantly by probing microtubules. Occasionally, chromosomes may become damaged. An arm of the chromosome may be broken and the fragment lost, causing deletion. The fragment may incorrectly reattach to another, non-homologous chromosome, causing translocation. It may reattach to the original chromosome, but in reverse orientation, causing inversion. Or, it may be treated erroneously as a separate chromosome, causing chromosomal duplication. The effect of these genetic abnormalities depend on the specific nature of the error. It may range from no noticeable effect, cancer induction, or organism death.


Endomitosis is a variant of mitosis without nuclear or cellular division, resulting in cells with many copies of the same chromosome occupying a single nucleus. This process may also be referred to as endoreduplication and the cells as endoploid.[2] An example of endomitosis would be what occurs in megakaryocytes to generate platelets within its cytoplasm.[19]

Timeline in pictures

Real mitotic cells can be visualized through the microscope by staining them with fluorescent antibodies and dyes. These light micrographs are included below.


Mitosis - Phases


The cell cycle
The cell cycle

The mitotic phase is a relatively short period of the cell cycle. It alternates with the much longer interphase, where the cell prepares itself for cell division. Interphase is divided into three phases, G1 (first gap), S (synthesis), and G2 (second gap). During all three phases, the cell grows by producing proteins and cytoplasmic organelles. However, chromosomes are replicated only during the S phase. Thus, a cell grows (G1), continues to grow as it duplicates its chromosomes (S), grows more and prepares for mitosis (G2), and divides (M).[3]


In plant cells only, prophase is preceded by a pre-prophase stage. In highly vacuolated plant cells, the nucleus has to migrate into the center of the cell before mitosis can begin. This is achieved through the formation of a phragmosome, a transverse sheet of cytoplasm that bisects the cell along the future plane of cell division. In addition to phragmosome formation, preprophase is characterized by the formation of a ring of microtubules and actin filaments (called preprophase band) underneath the plasmamembrane around the equatorial plane of the future mitotic spindle and predicting the position of cell plate fusion during telophase. The cells of higher plants (such as the flowering plants) lack centrioles. Instead, spindle microtubules aggregate on the surface of the nuclear envelope during prophase. The preprophase band disappears during nuclear envelope disassembly and spindle formation in prometaphase.[6]


Prophase: The two round objects above the nucleus are the centrosomes. Note the condensed chromatin.
Prophase: The two round objects above the nucleus are the centrosomes. Note the condensed chromatin.

Normally, the genetic material in the nucleus is in a loosely bundled coil called chromatin. At the onset of prophase, chromatin condenses together into a highly ordered structure called a chromosome. Since the genetic material has already been duplicated earlier in S phase, the replicated chromosomes have two sister chromatids, bound together at the centromere by the cohesion complex. Chromosomes are visible at high magnification through a light microscope.

Close to the nucleus are two centrosomes. Each centrosome, which was replicated earlier independent of mitosis, acts as a coordinating center for the cell's microtubules. The two centrosomes nucleate microtubules (which may be thought of as cellular ropes or poles) by polymerizing soluble tubulin present in the cytoplasm. Molecular motor proteins create repulsive forces that will push the centrosomes to opposite side of the nucleus. The centrosomes are only present in animals. In plants the microtubules form independently.

Some centrosomes contain a pair of centrioles that may help organize microtubule assembly, but they are not essential to formation of the mitotic spindle.[7]


Prometaphase: The nuclear membrane has degraded, and microtubules have invaded the nuclear space. These microtubules can attach to kinetochores or they can interact with opposing microtubules.
Prometaphase: The nuclear membrane has degraded, and microtubules have invaded the nuclear space. These microtubules can attach to kinetochores or they can interact with opposing microtubules.

The nuclear envelope disassembles and microtubules invade the nuclear space. This is called open mitosis, and it occurs in most multicellular organisms. Fungi and some protists, such as algae or trichomonads, undergo a variation called closed mitosis where the spindle forms inside the nucleus or its microtubules are able to penetrate an intact nuclear envelope.[8][9]

Each chromosome forms two kinetochores at the centromere, one attached at each chromatid. A kinetochore is a complex protein structure that is analogous to a ring for the microtubule hook; it is the point where microtubules attach themselves to the chromosome.[10] Although the kinetochore structure and function are not fully understood, it is known that it contains some form of molecular motor.[11] When a microtubule connects with the kinetochore, the motor activates, using energy from ATP to "crawl" up the tube toward the originating centrosome. This motor activity, coupled with polymerisation and depolymerisation of microtubules, provides the pulling force necessary to later separate the chromosome's two chromatids.[11]

When the spindle grows to sufficient length, kinetochore microtubules begin searching for kinetochores to attach to. A number of nonkinetochore microtubules find and interact with corresponding nonkinetochore microtubules from the opposite centrosome to form the mitotic spindle.[12] Prometaphase is sometimes considered part of prophase.


Metaphase: The chromosomes have aligned at the metaphase plate.
Metaphase: The chromosomes have aligned at the metaphase plate.

As microtubules find and attach to kinetochores in prometaphase, the centromeres of the chromosomes convene along the metaphase plate or equatorial plane, an imaginary line that is equidistant from the two centrosome poles.[12] This even alignment is due to the counterbalance of the pulling powers generated by the opposing kinetochores, analogous to a tug-of-war between equally strong people. In certain types of cells, chromosomes do not line up at the metaphase plate and instead move back and forth between the poles randomly, only roughly lining up along the midline. Metaphase comes from the Greek μετα meaning "after."

Because proper chromosome separation requires that every kinetochore be attached to a bundle of microtubules (spindle fibers) , it is thought that unattached kinetochores generate a signal to prevent premature progression to anaphase[1] without all chromosomes being aligned. The signal creates the mitotic spindle checkpoint.[13]


Early anaphase: Kinetochore microtubules shorten
Early anaphase: Kinetochore microtubules shorten

When every kinetochore is attached to a cluster of microtubules and the chromosomes have lined up along the metaphase plate, the cell proceeds to anaphase (from the Greek ανα meaning “up,” “against,” “back,” or “re-”).

Two events then occur; First, the proteins that bind sister chromatids together are cleaved, allowing them to separate. These sister chromatids turned sister chromosomes are pulled apart by shortening kinetochore microtubules and move toward the respective centrosomes to which they are attached. Next, the nonkinetochore microtubules elongate, pushing the centrosomes (and the set of chromosomes to which they are attached) apart to opposite ends of the cell.

These two stages are sometimes called early and late anaphase. Early anaphase is usually defined as the separation of the sister chromatids, while late anaphase is the elongation of the microtubules and the microtubules being pulled farther apart. At the end of anaphase, the cell has succeeded in separating identical copies of the genetic material into two distinct populations.


Telophase: The decondensing chromosomes are surrounded by nuclear membranes. Note cytokinesis  has already begun, the pinching is known as the cleavage furrow.
Telophase: The decondensing chromosomes are surrounded by nuclear membranes. Note cytokinesis has already begun, the pinching is known as the cleavage furrow.

Telophase (from the Greek τελος meaning "end") is a reversal of prophase and prometaphase events. It "cleans up" the after effects of mitosis. At telophase, the nonkinetochore microtubules continue to lengthen, elongating the cell even more. Corresponding sister chromosomes attach at opposite ends of the cell. A new nuclear envelope, using fragments of the parent cell's nuclear membrane, forms around each set of separated sister chromosomes. Both sets of chromosomes, now surrounded by new nuclei, unfold back into chromatin. Mitosis is complete, but cell division is not yet complete.


Cytokinesis is often mistakenly thought to be the final part of telophase, however cytokinesis is a separate process that begins at the same time as telophase. Cytokinesis is technically not even a phase of mitosis, but rather a separate process, necessary for completing cell division. In animal cells, a cleavage furrow (pinch) containing a contractile ring develops where the metaphase plate used to be, pinching off the separated nuclei.[14] In both animal and plant cells, cell division is also driven by vesicles derived from the Golgi apparatus, which move along microtubules to the middle of the cell. [15] In plants this structure coalesces into a cell plate at the center of the phragmoplast and develops into a cell wall, separating the two nuclei. The phragmoplast is a microtubule structure typical for higher plants, whereas some green algae use a phycoplast microtubule array during cytokinesis.[16] Each daughter cell has a complete copy of the genome of its parent cell. The end of cytokinesis marks the end of the M-phase.