Best of both worlds vacuum -channel transistors

Vacuum tubes have almost completely disappeared from the electronics scene. Semiconductor, the cheaper, lighter, more efficient, and easier to manufacture of the two technologies replaced the old, energy guzzling, bulky cathode ray tubes.
But vacuum tubes have its own virtues. They are more robust in high-radiation environments such as outer space. And since electrons travel faster in a vacuum than through a semiconductor, vacuum tubes are an intrinsically better medium for electricity.
An international team of researchers from NASA's Ames Research Center in Moffett Field, Calif., and the National Nanofab Center in Korea have combined the best traits of both technologies by making a tiny version of vacuum tubes that could be incorporated into circuits. Their prototype, a vacuum channel transistor, is just 150 nanometers long and was made using conventional semiconductor fabrication methods. Its small size allows it to operate at fewer than 10 volts, much less than a retro vacuum tube requires; with further work, the device could be made to use about 1 volt, which would make it competitive with modern semiconductor technology.
In a paper to bw published in the American Institute of Physics' (AIP) journal Applied Physics Letters, the authors write that such a transistor could be useful for applications in hazardous chemical sensing, noninvasive medical diagnostics, and high-speed telecommunications, as well as in so-called "extreme environment" applications for military and space.

###

Please lookArticle: "Vacuum nanoelectronics: back to the future? – gate insulated nanoscale vacuum channel transistor," is accepted to Applied Physics Letters.
Authors: Jin-Woo Han (1), Jae Sub Oh (2), and M. Meyya

16 percent of cancers worldwide are are largely preventable or treatable

 
The researchers from the International Agency for Research on Cancer (IARC) used  data from a number of sources including GLOBOCAN statistics on incidence estimates for 27 cancers in 184 countries and  calculated that around 16% of all cancers worldwide in 2008 were infection-related, with the fraction of cancers related to infection about three times higher in developing than in developed countries (22.9% vs 7.4%).

According to the new estimates published in the online First  The Lancet Oncology.,of the 7.5 million deaths from cancer worldwide in 2008, an estimated 1.5 million were due to potentially preventable or treatable infections. 80% of these occur in less developed regions.

"Infections with certain viruses, bacteria, and parasites are one of the biggest and preventable causes of cancer worldwide…Application of existing public-health methods for infection prevention, such as vaccination, safer injection practice, or antimicrobial treatments, could have a substantial effect on future burden of cancer worldwide", explain Catherine de Martel and Martyn Plummer from the IARC France, lead authors of the study.
 
de Martel and colleagues did a systemic analysis to estimate the proportion of cancers that could be attributed to infection globally and in eight regions by calculating the population attributable fractions (PAF)—the proportion of new cancer cases in a population that could have been prevented by an intervention on a specific exposure.

The fraction of infection-related cancers varied widely between regions, from 3.3% in Australia and New Zealand to 32.7% in sub-Saharan Africa.

"Many infection-related cancers are preventable, particularly those associated with human papillomaviruses (HPV), Helicobacter pylori, and hepatitis B (HBV) and C viruses (HCV),", say the authors, adding that these four main infections are together estimated to be responsible for 1.9 million cases, most of which are gastric, liver, and cervical cancers.

Cervical cancer accounted for around half of the infection-related burden of cancer in women, and in men liver and gastric cancers accounted for more than 80%.

The 2011 UN high-level meeting on non-communicable diseases highlighted the growing global agenda for prevention and control of non-communicable diseases. [But] although cancer is considered a major non-communicable disease, a sizable proportion of its causation is infectious and simple non-communicable disease paradigms will not be sufficient.", the researchers concluded.

In an accompanying Comment, Goodarz Danaei from Harvard School of Public Medicine, Boston, USA says: "Their estimates show the potential for preventive and therapeutic programmes in less developed countries to significantly reduce the global burden of cancer and the vast disparities across regions and countries."

"Since effective and relatively low-cost vaccines for HPV and HBV are available, increasing coverage should be a priority for health systems in high-burden countries.", he added



                                                            xxxxxxx

Low Dose CT useful in staging myeloma

Computed tomography scans get lot of  publicity often because they are used at times indiscriminately. It is a unique diagnostic tool when used in clinically needed examinations. Recently,  researchers have shown that low dose whole body CT is nearly four times better than radiographic skeletal survey, the standard of care in the U.S., for determining the extent of disease in patients with multiple myeloma.

The study, conducted at the University of Maryland in Baltimore, included 51 patients who had both a radiographic skeletal survey as well as a low dose whole body CT examination. The total number of lesions detected in these patients with low dose whole body CT was 968 versus 248 detected by radiographic skeletal survey, said Kelechi Princewill, MD, the lead author of the study.

The study was presented on May 2 at the American Roentgen Ray Society annual meeting in Vancouver, Canada.

 "The stage of disease determines treatment, and the study found that in 31 patients, the stage of disease would have been different with low dose whole body CT. Thirteen patients would have been upstaged from stage I to stage II; nine patients would have been upstaged from stage I to stage III and nine patients would have been upstaged from stage II to III based on additional lesions detected on the low dose whole body CT," said Dr. Princewill.

Low dose whole body CT was significantly better than radiographic skeletal survey in detecting lesions in the spine, ribs, sternum and flat bones, added Dr. Princewill.

In Europe, the use of low dose whole body CT is accepted as an accurate alternative to radiographic skeletal survey for detecting bone lesions in these patients, said Dr. Princewill.

A concern about radiation dose may be one of the reasons why it is not widely accepted in the U.S., he said. "Our study employed a low dose protocol, with an average recorded CT dose of 4.1 mSv. That compares to 1.8 mSv for the radiographic skeletal survey. Using modified protocols and exposure parameters, we were able to significantly reduce the radiation doses to our patients without significantly compromising the image quality required to detect myeloma lesions.

The average CT dose used in our study was approximately nine times lower than doses used in the acquisition of standard body CT studies," Dr. Princewill said.

Radiologists rank themselves as less than competent on health policy issues

 

Radiologists classify themselves as less competent than other physicians regarding knowledge of patient imaging costs and patient safety, a new study shows.The study conducted at Thomas Jefferson University in Philadelphia and Northwestern University in Chicago compared 711 radiologists to 2,685 non-radiology physicians. "On a scale of one to five, with five being highly competent, understanding of patient safety was rated as 3.1 by radiologists and 3.33 by non-radiologists," said Rajni Natesan, MD, an author of the study from Northwestern University. Patient imaging c

 You may access the news item at:
http://www.eurekalert.org/pub_releases/2012-04/arrs-rrt041912.php >