Science

Magazine Overview

Title: Science
Issue Date: 15 December 1967
Publisher: American Association for the Advancement of Science
Country: USA
Language: English
Price: $1

This issue of Science magazine features articles and letters addressing scientific skepticism, health concerns related to radiation, and advancements in biochemical separation techniques.

Student Skeptics Study UFO's

Thornton Page, from the Astronomy Department at Wesleyan University, writes about his experience teaching a course on "Flying Saucers." He explains how he uses student interest in UFO reports to teach fundamentals of astronomy and physics. The course aims to help students understand the scientific principles behind UFO sightings. Page notes that the "Establishment" is often opposed by young people and suggests that this tendency can be exploited to teach science effectively. He wishes for statistics and analysis from the Condon panel to aid in teaching, believing students will avidly seek loopholes and learn science in the process.

Are Dental X-Rays Dangerous?

Fred M. Medwedeff, from Nashville, Tennessee, challenges the arguments presented by Albert Richards of the American Dental Association regarding radiation hazards from dental X-rays. Richards had pointed to studies suggesting dentists live longer and die less frequently from blood diseases. Medwedeff refutes this by stating:

1. Shielding: Blood-forming organs are deep within the body and shielded by bone and tissue, receiving only low-kilovolt-peak scattered radiation, not the primary beam.
2. Statistical Validity: The incidence of leukemia is low (less than 15,000 cases per year in the US), making it difficult to draw statistically significant conclusions from the data, especially when comparing it to the large population of dentists.
3. Time Frame: Widespread use of X-rays in dentistry is a recent phenomenon (last 20 years), meaning many older dentists did not have extensive exposure, and many have delegated the procedure to assistants.

Medwedeff suggests that Richards' figures are not realistic because leukemia deaths often occur in children, whereas dentists are typically adults. He proposes that skin cancer, a potential result of low-kilovolt radiation, would be a more appropriate comparison, noting that many dentists are aware of colleagues who have contracted skin cancer from their X-ray machines.

A response clarifies that the age-at-death figures cited by Medwedeff are from a 1955-1960 study by the American Dental Association. It notes that leukemia and aleukemia were classified under "neoplasms," not "diseases of the blood-forming organs," as Medwedeff implied.

Thin-layer gel filtration with Sephadex SUPERFINE

This section introduces Sephadex Superfine, a product that combines the benefits of Sephadex gel filtration and thin-layer chromatography. It is presented as an important tool for analytical methods, especially when dealing with small sample quantities.

Advantages and Applications:

• Experimental Optimization: Useful for determining the optimal conditions for column experiments.
• High Resolution: Can be used in place of normal Sephadex in gel filtration columns when very high resolution is required.
• Supporting Medium: Serves as a supporting medium in column electrophoresis and partition chromatography.

The article includes a graph showing the correlation between the molecular weight of nine proteins and their migration rate in thin-layer gel filtration on Sephadex Superfine G-100. The data for this graph was correlated by expression on a common basis of 6 cm migration by cytochrome c, referencing a study by P. Andrews.

Availability:

Six types of Sephadex (G-25 to G-200) are available in the SUPERFINE grade. The small particle size (10-40 microns) allows for the preparation of thin layers, even with more porous gels.

Fractionation Ranges: The table lists the approximate fractionation ranges for polysaccharides and proteins for each Sephadex type (G-25, G-50, G-75, G-100, G-150, G-200).

Technical Information: For further details, including a booklet on Thin-Layer Gel Filtration, readers are directed to Pharmacia Fine Chemicals Inc. in Piscataway, New Jersey, or Pharmacia (Canada) Ltd. in Montreal. Inquiries from outside the US and Canada should be sent to Pharmacia Fine Chemicals in Uppsala, Sweden.

Recurring Themes and Editorial Stance

The issue reflects a commitment to scientific rigor and critical inquiry. The letters section showcases debates on scientific claims, such as the dangers of dental X-rays, encouraging a skeptical approach to data and methodology. The technical article on Sephadex Superfine highlights the advancement of biochemical techniques, emphasizing precision and analytical capabilities. The overall stance appears to be one that values empirical evidence, statistical validity, and the application of scientific principles to diverse fields, including education and health.