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Science Experiments / Getting creative with a rolling pin

« on: 25/10/2013 18:03:01 »

Hit someone over the head with it
Use it as a zip wire
Store toilet paper rolls on it
Burn it for heat
Use it as a rounders bat

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Question of the Week / Re: Discuss: Will my skin soak up the calories in skin cream?

« on: 16/04/2012 15:51:35 »

I spoke with Prof Richard Guy at Bath University about this and he comments:

"Babies born prematurely have two important characteristics: (a) they are pretty small and, as you say, they have a high surface area to volume ratio, and (b) they have incompletely formed stratum corneum - that is, their skin barrier is not fully developed.  The reason for the latter is self-evident: in the womb, the baby is basically submerged in a water bath and is in no need of a barrier to water loss.  As the gestational period comes to its conclusion, however, and the foetus prepares for birth, the differentiation of the epidermis steps up a gear to generate a proper stratum corneum such that, on "popping out", the newborn has a skin barrier that's not much different from that of a healthy adult.

It's well-established in the literature and in clinical practice that premature babies have to be carefully monitored and maintained in well-controlled conditions, in particular, to stop excessive water loss across their skin.  Once has to be careful too with exposure to exogenous substances which may easily cross the less-than-fully-developed skin and cause potentially harmful effects.  The observation that rubbing oil on premature neonatal skin results in the appearance of some constituents in the blood is not too surprising therefore.  It's probable that the oil is also enhancing the weak skin barrier function in these babies and this will, in turn, improve their well-being.

Normal skin turnover means that we lose, on average, about one cell layer a day and that we always have a final layer of cells about to fall off the body.  However, with the exception of certain disease states where these layers of finally desquamating cells are not shed correctly, we do not build up large amounts of dead cells on the surface.  Further, when we apply lotions or creams, etc., the massaging in of the formulation almost certainly rubs off those soon-to-be-lost dead cells and they pose no really effective barrier to the uptake of material, therefore.

The skin and gut have completely different functions, of course.  The gut has evolved to be a an efficient mechanism by which we absorb nutrients from food and the pH, enzyme content, structure, and so on are highly developed to make this work.  This includes the absorption of fat which, at least in days gone by, was rather important in keeping Homo Sapiens alive.  In contrast, the skin has evolved to be a barrier, as described in my original response, and has no absorptive role in terms of keeping the organism alive.  As a result, it does not possess all those things which makes the gut so good at turning food into the building blocks that we need for life.

As an aside, though, it's fun to point out that the external skin and the gut (and by gut I would mean from the mouth to the anus) form a continuous, essentially uninterrupted surface, the functions of which are really distinct depending on where you are!

Hope that helps.  Best wishes,  R"

Thanks for your comments all!, Hannah

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Physiology & Medicine / Re: Does sleep make bad memories worse?

« on: 04/04/2012 11:07:37 »

A listener got in touch after hearing this story saying:

Hello ,
 
In the news section of the 22nd Jan 2012 podcast , there is an article that talks about sleep and emotions or memories .
 
http://www.thenakedscientists.com/HTML/content/news-archive/news/2470/
 
But I have previously read an article on a website about the same subject
 
http://sciencenetlinks.com/science-news/science-updates/dreams-emotions/
 
and I’m really confused .
 
I’m sorry , I’m not an expert or something . I did not understand the whole thing
 
and I just thought you might help me .
 
 By the way , I’m new to The Naked Scientists podcast and I like it very much
 
I would be grateful if you could respond to my message .
 
Thanks
4-3-2012

We asked Rebecca Spencer, lead author of the study and she replied:

Hi Hannah,

The simplest answer is that we measure something totally different.  We're most interested in how sleep changes emotion on a negative to neutral to positive scale, in other words, how emotionally negative is it.  The type if emotion (neg, pos, neutral) is ignored in Walker's work instead the rate just "intensity" regardless of emotion type.  Note that Walker also did not measure the relationship with memory either even though his model makes predictions regarding the interaction of memory and emotionality changes.

The perhaps more complicated part of the answer is that in addition to measuring subjective valence (negative->neutral) we measured arousal.  We saw no sleep effects on arousal yet this measure should most closely match Walker's measure if "intensity".  If it's the case that these capture the same construct, then I would turn to analytical or methodological differences across our studies.  They analyzed their data in an much different......way too.  For this reason, you will see a link to supplementary materials at the end of our paper.  In these materials, we plot our data using their approach and we still don't agree.  So then you could turn to methodological differences.  If I remember right (I don't have the Walker paper with me) they combine negative and positive images and we know how you process a negative item in a positive context will be different than if just paired with neutrals  They also use stimuli of a much different range of valence and arousal (if I remember right, much more mild than ours). 

All in all, it's up to both of our labs to continue to sort this out and I do believe we will! 

I hope this helps!

Rebecca

So they are measuring different things, hence they get different results. The relationship between sleep, emotion and memory is an area of great interest to neuroscientists, mainly because it is such a puzzle, something that they are trying to understand more about.

Looking at differences in results from studies employing different paradigms will, hopefully, help to tease out our eventual full understanding of the area.

Hannah

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Radio Show & Podcast Feedback / Re: Discuss: What happens when we screw with our sleep patterns?

« on: 23/03/2012 11:44:37 »

Hi Airthumbs, I just spoke with Dr Michael Hastings about this and he agrees with Chris, saying:

"The rule of thumb is that for every one hour change in time zone / shift pattern, it takes 1 day to adjust.  So flying from London to New York = 5 hours difference, it takes 5 days in New York to get back into synch.  Then return journey will be another 5 days once back in London to get to London time.  Obviously people vary, but most find going west/ moving to a later shift, is easier than the opposite".

So, essentially a shift of one hour per night is ok.