Photograph courtesy of the Exploratorium via Creative Commons.
When viewed from the Earth, a solar eclipse happens when the Moon passes between the Sun and Earth so the Moon blocks the Sun. If the Moon only blocks part of the Sun, then it is a partial solar eclipse. If the Sun is fully obscured by the Moon, then it is a total solar eclipse. Total eclipses are rare at any one location, because the Moon fully blocks the Sun along only a narrow path on the Earth’s surface traced by the Moon’s shadow.
According to the National Aeronautics and Space Administration (NASA), a partial solar eclipse will occur on May 20, 2012. This is the first solar eclipse to happen in the United States since 1994. In San Francisco, this eclipse will begin at 5:15 pm and end at 7:40 pm. The maximum eclipse will occur at 6:32 pm when 85% of the sun will be obscured. This partial eclipse will look the like the Moon has a ring of fire surrounding it.
Although it is tempting, you shouldn’t view a solar eclipse with the naked eye. Your eye-lens will concentrate the sun’s light onto your retina, and this can cause permanent eye damage. You can safely view a solar eclipse wearing inexpensive solar glasses (with a “CE” label), which have filters that block out 99.99% of the sun’s light and 100% of the harmful ultraviolet rays. Don’t have solar glasses? You can also safely view a solar eclipse by indirect projection – projecting the image of the sun onto a white piece of paper using a pinhole camera. The San Francisco Exploratorium has directions on how to make a pinhole camera.
The Field Trip Podcast icon, courtesy of Kara Platoni.
Looking back, the only school field trip that I remember was our trip to the San Francisco Exploratorium. I enjoyed the fun interactive science exhibits, but what I remember best is the tactile dome. I entered into total darkness and spent the next hour feeling, crawling and sliding my way through a 3-D maze. The purpose of the tactile room is to explore a disorienting world in which you can only rely on touch. For a kid, the challenge is to do that as quickly as possible.
However, that field trip is tame compared to what Kara Platoni, Eric Simons, and Casey Miner have in mind. They’ve launched a new podcast, The Field Trip, that broadcasts their real world science adventures. To add a little more intellectual rigor, they also interview an expert guest in their radio studio for each episode. Beginning on May 14, a new episode will air weekly each Monday through June 4.
For more information on the podcast series, check out my KQED Quest blog.
Photograph courtesy of Euromagic via Creative Commons.
My nephew is one of the 6 million children in the United States with food allergies. He has a severe nut allergy, requiring an EpiPen (adrenaline) injection and immediate trip to the emergency room after contact with someone whose touched or eaten nuts. His rapid onset of life-threatening symptoms includes swelling of the throat, difficulty breathing, and hives. He isn’t alone. The number of children with peanut allergies has tripled in the last decade. Every three minutes a food allergy reaction sends someone to the emergency room and every 6 minutes the reaction is one of life-threatening anaphylaxis.
However, the 15 million people with food allergies now have hope. New clinical trials show promise for three experimental treatments: oral immunotherapy, sublingual immunotherapy and food allergy herbal formula-2. Scientists are also trying to understand how food allergies develop to help prevent them.
For more information on food allergies, check out my KQED Quest blog.
University College Hospital in London. Courtesy of Steve Parkinson via Creative Commons.
Standard prostate cancer treatments, such as prostatectomy surgery or radiotherapy, often lead to substantial side effects. These include erectile dysfunction (affecting 30-70%) and urinary incontinence (affecting 5-20%). However, these unwanted side effects could be reduced, if prostate cancer treatments could target just the cancer tumors while harming less of their surrounding healthy tissue.
A promising “proof of concept” research study has just demonstrated that a new technique to treat localized prostate cancer may significantly reduce side effects compared to standard treatments. This study was carried out by researchers from University College London and the results were just published in the peer-reviewed medical journal The Lancet Oncology.
This new treatment uses high-intensity focused ultrasound (HIFU) to target and destroy prostate tumors, while causing minimal damage to their surrounding nerves and muscles. A small ultrasound probe is placed close to the prostate through the patient’s rectum. This probe emits a narrow beam of intense sound waves that heat the targeted cells to 80 C for one second, killing a targeted area about the size of a grain of rice. The probe is then moved to focus and destroy additional cancerous areas. The procedure is performed in the hospital under general anesthesia and most patients are back home within 24 hours.
Surgeon Hashim Ahmed from University College Hospital in London demonstrates in a BBC News short video how this probe heats only a small target area.
The “proof of concept” HIFU study was primarily focused on assessing the frequency and extent of side effects, rather than the success of the prostate cancer treatment. Forty-one men participated in the study, ranging in age from 45 to 80 years old. All participants had localized prostate cancer ranging from low to high risk, where 30 men (73%) had intermediate to high-risk disease. They also had a prostate volume of 40 mL or less in order to avoid an excessively long procedure. They had received no previous prostate treatment.
The prostate cancer tumor locations were identified using multiparametric MRI (magnetic resonance imaging) and a template-prostate-mapping biopsy. The identified tumors were then targeted by the HIFU treatment. The men were followed up at one, three, six, nine and twelve months after the HIFU procedure. Each follow-up included: (1) a PSA blood test to measure the levels of prostate specific antigen protein being produced by the prostate, since PSA is generally elevated for men with prostate cancer; and (2) questionnaires that evaluated side effects. In addition, the MRI and biopsy tests were repeated as part of the 6 months follow-up and an additional MRI was performed after a year.
Researchers found that a year after the HIFU treatment, 89% of the men still had erectile function and all were still continent. In addition, there was a significant decrease in PSA levels compared to baseline and 95% of the men showed no evidence of disease on the final MRI scan.
Clearly this HIFU pilot study has demonstrated a promising reduction in treatment side effects. However, it was a small observational study of 41 men and followed them for only a year. The results need to be confirmed by much larger clinical trials that assess both the effectiveness and safety of HIFU compared with standard therapies. As a result, the researchers at University College London have started recruiting patients for a larger phase 2 trial that will follow patients for 3 years.
Scientists Talk Funny 