I have been reluctant to blog on difficult to read top scientific articles mainly because our distracted lives and brains on the Internet and television has built up the left frontal cortex in our decision making and assessment processes but has seriously harmed our ability to concentrate for longer periods of time discussed thoroughly in the book The Shallows by Carr, a former editor at a large book publishing house who did observe his inability to concentrate on a book for more than 15 minutes.
I have in the past talked about our temporary working or shallow memory which has only a very small capacity and seconds of residence time which explains why skimming or being continually distracted by the Internet hyperlinks, blinking adds, crawls on television news, the seductive googling of everything and then skimming to find what we believe to support our arguments and even interruptions by children or a spouse, we are continually distracted and disrupted to really concentrate and absorb information slowly so the small working memory does not get overwhelmed as I have suggested in the past to really absorb and understand and remember what we read.
The long-term memory brain has close to infinite capacity and it is much more than a storage cabinet. Given enough sleep, the brain reorganizes and collates the information with other stored information to allow us to do deep thinking. That is why most breakthroughs happen to people who are obsessive about learning everything about something they love to do or learn. That is the main role of teachers, I think. Watch your students to see how they react to what you are saying and don't talk facing the blackboard.
Even with engineering juniors who are almost uniformly above average in intelligence, chemistry was not an easy topic for them to really understand. I gave them lots of short tests at the beginning of the hour to assess their weaknesses. Then watch them when I explain concepts and problem solving to see if they get it. Sometimes I explain things in three or four ways. They learned enough to get about half the A's at the end of the semester.
A friend sent me an email copy of the Harvard Health Newsletter June 2010 regarding what causes melanoma. Even though they know better, I assume, they clearly stated that UVB causes melanoma when the science says it is not clear at all and just from common sense, when sunscreens did not contain UVA protection which makes up the predominate sunlight and was not blocked and I also believe that due to lack of common sense, they keep thinking that melanoma is caused because people did not have enough sunblock for UVB!
The easy question we should ask is why did the increase in sunblock SPF not change the progression of melanoma? It is just like what the Republicans keep telling us about the Financial Disaster that made the middleclass and rich much poorer is due to too much Regulations! They want more deregulation!
Jim Kawakami, July 21, 2010, http://jimboguy.blogspot.com
Journal of Investigative Dermatology (2009) 129, 1608–1610. doi:10.1038/jid.2009.116 http://www.nature.com/jid/journal/v129/n7/full/jid2009116a.html
Frances P Noonan1 and Edward C De Fabo1
The authors state no conflict of interest.
1Department of Microbiology, Immunology, and Tropical Medicine, George Washington University Medical Center, Washington, DC, USA
Correspondence: Dr Frances P. Noonan, Department of Microbiology, Immunology, and Tropical Medicine, George Washington University Medical Center, 2300 Eye Street NW, Ross Hall, Room 113, Washington, DC 20037, USA. E-mail: drmfpn@gwumc.edu
UVB and UVA Initiate Different Pathways to p53-Dependent Apoptosis in Melanocytes
Abstract: The incidence of cutaneous malignant melanoma (CMM) has more than doubled in the past 25 years and continues to increase at over 3% per year across all age groups (Linos et al., this issue), and invasive and disseminated melanoma in young women has increased by almost 10% since 1992 (Purdue et al., 2008).
Early detection and excision of CMM can result in successful treatment, but disseminated disease is resistant to current therapies and has a very poor prognosis (Garbe and Eigentler, 2007). Sunlight exposure is a major risk factor for melanoma. In this issue, Waster and llinger investigate the effects of UVB and UVA on melanocytes.
… The molecular mechanisms by which sunlight initiates/promotes melanoma are unclear, and even the UV wavelengths responsible are a matter of controversy. …
UVB mutations in p53 play an important early role (Brash et al., 1996), data on the role of UV radiation in melanoma are conflicting. UVB mutations in p53 have not been found consistently in melanoma, and only a subset of melanoma appears in chronically sunlight exposed skin. … Nature Magazine is a premier scientific publication.
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In an albino HGF mouse model, UVB but not UVA (320–400 nm) initiated melanoma (De Fabo et al., 2004). In contrast, in a model of melanoma in genetically susceptible fish hybrids (Xiphophorus), both UVB and UVA initiated melanoma, but the investigators proposed that UVA was the major carcinogen in sunlight (Wang et al., 2001). Whether this model holds for mammalian melanoma is unknown. …
UVB is directly absorbed by DNA and readily initiates DNA damage, notably cyclobutane pyrimidine dimers and 6-4 photoproducts, which can result in UVB mutations. However, DNA has an absorption spectrum in the UVA region that is several orders of magnitude lower than the peak UVB absorption, so direct absorption of UVA by DNA is minimal. In contrast, UVA exerts its actions indirectly by photosensitization via absorption by a variety of cellular chromophores, which can result in the generation of oxidative stress.
UVB and UVA Initiate Different Pathways to p53-Dependent Apoptosis in Melanocytes
In this issue, an elegant study by Waster and llinger (2009) investigates apoptosis by UVB and UVA in melanocytes. The authors report that in both cases apoptosis was p53 dependent and proceeded via the intrinsic pathway, but that the mechanisms by which p53 initiated the apoptotic process were different. …
The paper by Waster and llinger (2009) clearly points to important wavelength-dependent effects of UV radiation in melanocytes. If both UVA and UVB are carcinogens for melanoma, this would be significant, not only in terms of mechanisms but also for risk assessment and the design of effective prevention strategies. In particular, if UVA is carcinogenic for melanoma in humans, this would be a compelling reason to limit exposure to tanning beds—particularly in young people (Autier and Boyle, 2008). … http://www.nature.com/jid/journal/v129/n7/full/jid2009116a.html
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