Pager attacks in Lebanon, and resurrecting ancient seeds
In this edition of The Naked Scientists: what do we know about the pagers and walkie-talkies used to attack Hezbollah fighters in Lebanon? Also the landmark study on the impact of pregnancy on the human brain. And how scientists in Israel have grown a one thousand-year-old seed that might fill in a missing link in the Bible...
In this episode
00:59 - Israel detonate pagers and walkie-talkies in targeted attack
Israel detonate pagers and walkie-talkies in targeted attack
Scott Lucas, University College Dublin
There are reports that Israel's spy agency Mossad is responsible for detonating explosives hidden inside pagers and walkie-talkies used by the Hezbollah militant group in Lebanon. The blasts, which came within a day of each other, have killed more than twenty people and left thousands more injured. The attacks follow the resumption of Hezbollah’s long standing rancour with Israel, with hostilities increasing dramatically since the start of the war in Gaza. So, what do we know about the targeting of these tech devices inside Lebanon? Scott Lucas is at the University College Dublin’s Clinton Institute, and is also the founder and editor of EA Worldview - which is a leading website on international affairs…
Scott - On September 17th, across Lebanon, a text message was sent to thousands of pagers that belonged to members of Hezbollah. When people looked at that text message, in fact, there was a tiny amount of explosive in the pagers that detonated, which meant that at least 12 people were killed, almost 3000 wounded. Many of them suffered hand injuries from holding the pagers or eye injuries, because of course they were looking at the screen. We thought that would be the full story. But then on September 18th, the same type of operation was carried out through walkie-talkies that again, were believed to be used by Hezbollah members. So we are at a point where having abandoned the use of cell phones because they could be tracked, Hezbollah now finds itself vulnerable with almost any form of communication.
Will - I suppose that's important to clarify from the get go, is that these walkie talkies and pages had an extra element added to them, and that people who own these devices outside of Lebanon are not in any danger.
Scott - No. We do need to make clear that this was not a fault of the devices, the pagers, the walkie-talkies, which means that we have a general threat to people outside of Lebanon. We can now piece the story together in terms of why there was a specific threat, in other words this explosive, and that is because the Israelis manufactured the pagers and they probably manufactured the walkie-talkies. What happened is that the Israelis would manufacture the pagers and they would put in a tiny amount, we think about three grams of explosive, in each of them. Now, of course, the Israelis wouldn't send this to Hezbollah and say, 'here you go, use them'. They were sent through a front company that had been set up by the Israelis, but when Hezbollah received them, they simply thought, oh, this is an order that we had placed with this company that we thought was a legitimate company that had no connection with Israel. They would've no reason to think that the pagers had been doctored. We don't know the full details yet on the walkie-talkies, but it looks like that there was a similar operation where the Israelis used a company in the name of Japan's ICOM who has said, 'no, these, these weren't our walkie talkies that exploded, even though our name was on them', that the Israelis actually manufacture these walkie talkies, put the ICOM name on them, and got them into Hezbollah's hands. This was an elaborate operation that would've taken many, many months involving the setting up of at least three front companies, involving setting up a production capability, involving setting up a supply chain, all for one single purpose to make walkie-talkies, to make pagers not for the general market, but to get them into the hands of Hezbollah members and then to wreak havoc when they exploded.
Will - You touched on it before, but why were Hezbollah resorting to using walkie talkies and pages?
Scott - The immediate conflict that we have between Israel and the Lebanese organisation Hezbollah has escalated since last October 7th, alongside Israel's military operations in Gaza. Because Israel has carried out targeted assassinations that have killed leaders of Hezbollah as well as leaders of the Palestinian organisation Hamas, the Hezbollah overall leader, Hassan Nasrallah, ordered Hezbollah members to stop using cell phones because cell phones enable people to track you. When you use a pager, it reduces your communications toolbox, but it also limits the possibility of surveillance. So Hezbollah's leader Hassan Nasrallah had issued that order to stop using cell phones, believing it would increase their security, their operational security. But of course, because the Israelis knew he had issued this order, they immediately started looking at the alternative, which is, can we penetrate the pagers? Can we strike Hezbollah through that?
Will - Do we know what the effect on the communications network is going to be in Lebanon? Because obviously people are going to be shying away from pagers and walkie-talkies for the time being. But there are places like hospitals for which those devices are pretty essential.
Scott - I mean, there was a clear signal just after the pager explosions took place of this widespread effect. And how this is an attack that doesn't just simply target Hezbollah. It affects communications inside a country which is economically crippled, uh, and faces security threats. The United Nations told its staff, staff who are there to assist people in Lebanon in the midst of an economic emergency, a social emergency. That's it. Don't use your phones. Other organisations have done the same thing. You know, the Israelis are trying to reduce Hezbollah to an early 20th century state by removing the modern means of communications upon which we rely.
06:47 - How pregnancy affects the mother's brain
How pregnancy affects the mother's brain
Laura Pritschet, University of Pennsylvania
Detailed brain scans of a mother before, during and after pregnancy have revealed stark changes in the size and connectivity of many brain regions, particularly those related to socialisng and emotional processing. The study - which has been published in Nature Neuroscience - claims to be one of the first comprehensive maps of the brain during the 9 month gestation period, and with some 85% of women falling pregnant at some point in their lives, some say proper research in this area is long overdue. Scientists suspect the changes relate to a pruning down of connections within the brain, perhaps optimising the way some brain areas communicate with one another, possibly facilitating mother-baby bonding or caregiving. Here to tell us more is lead author Laura Pritschet, post doctoral fellow in the department of psychiatry at the University of Pennsylvania.
Laura - What we know thus far in the existing literature is based on experiments that have done sort of a snapshot approach where we have taken women before they're going to try to become pregnant and scan their brain looking at a bunch of details of their grey matter, their white matter, fluid in their brain. And then we will bring them back and scan them again early postpartum when they've just delivered. And that is really interesting and it provides the strongest evidence to date that neural changes are happening from that time where they're trying to become pregnant to delivering a baby. There are these grey matter reductions from pre to post pregnancy and those reductions can persist up to six years postpartum. And that includes cortical grey matter volume, it includes the thickness of the cortical sheet, which is that outer layer of the brain. But the outstanding question was, what does that pace of change, what does that time course of those reductions, look like?
Chris - Indeed. And is it uniform across pregnancy or are there surges in cortical loss, and then it settles down? So how did you actually go about doing this and who did you study?
Laura - What we've done in the last decade or so is really put that spotlight back on the individual asking, are we representative of ourselves at a single time point? And in fact, that temporal flow, those fluctuations in our day-to-day life could be reflected in the brain. And that's not something we're capturing. And so they've turned to this sort of precision imaging dense sampling approach where now we're bringing in fewer samples of people, but scanning them and studying them over long periods of time and getting a lot of phenotypic data on them. Meaning we can study their mood, we could get their blood, we can ask them a tonne of questions and get a lot of information on the individual. And we thought that is the perfect model to explore some of these hormone related questions we have for the brain because the brain itself is a dynamical system. It's not static. It's ebbing and flowing. And so are hormones. And at that time, we had a colleague of ours come to us and say, look, I'm going to be family planning soon. And what if we took that approach and scanned myself throughout this whole journey? So we had a volunteer, she's the co-senior author on this paper, Liz Chrastil, she's a professor at the University of California Irvine. And we scanned her brain three weeks before she began IVF all the way through two years postpartum.
Chris - Was this with MRI? Magnetic resonance imaging?
Laura - Yes. A 30 to 45 minute brain scan with MRI.
Chris - And this enabled you to get the gross anatomy? What did that show you? Was there any particular hotspot in pregnancy when things changed or was it just a gradual change? And if you map that onto what's happening to her hormones, is there a correlation?
Laura - Yes. All great questions. And actually, the answer differs when you think about different metrics of brain anatomy. So with respect to starting with grey matter volume, the brain metric that has been studied the most, this is where the cell bodies live, the neurons, we found this sort of linear decline. Grey matter volume was reducing as gestational week was advancing and sex hormones were rising. That was pretty widespread. 80% of the brain regions we looked at showed that sort of relationship. There wasn't any sort of big inflection point. And then in postpartum, those grey matter volume reductions bounced back a little bit, but they did not return to baseline levels. And we see the same pattern for cortical thickness. So you've got the actual volume, the area within those regions, and you have the thickness of the cortex itself. Those are really tied metrics to each other. However, at the same time, you can think of this as, well, if a tissue in my brain is reducing, something's got to fill that space <laugh>. We are not walking around with these sort of holes in our brain. And that's what we saw. We saw cerebral spinal fluid increase over pregnancy. We saw lateral ventricles expand during pregnancy. And it just shows this beautiful choreographed dance of what's changing over this period. Now, one of the most interesting, and I would argue novel findings here, is that we also had our subject do what we call as a diffusion imaging scan, which allows us to capture information on white matter tracts in the brain, which is the myelinated axons that are facilitating communication between neuron A and neuron B. And what we found is that the integrity of that white matter was increasing over pregnancy and it peaked in the second trimester. So it showed sort of a non-linear rise over pregnancy. And again, there are some caveats to us talking about those inflection points and pace when we're speaking about only a single subject. But that is very interesting to us because, of the articles that have looked pre to post pregnancy and done those same sorts of metrics looking at white matter microstructure, they didn't find any differences. And that could be due to us not capturing that big metamorphosis in the brain because we didn't look within gestation itself.
Chris - Does this give us any clues then as to what might be going on for the fraction of women who, after they've had a baby, can develop really profound mood disorders like the baby blues, for example, or even some psychiatric conditions which are much more likely to manifest in that period?
Laura - Yeah, this is the million dollar question. I think what we're trying to do right now is say, okay, right now we're going to tackle this. It's a basic science question. Let's bring a lot of people in. Let's create this normalised map like brain charting over pregnancy to establish what that pace looks like across a demographically enriched cohort of people. Then we can go in and say, okay, well do deviations from that pace itself lead to these sorts of divergent brain outcomes. And then additionally, we need to find markers, biomarkers, of the subsample of women who are at highest risk for perinatal and postpartum depression. We know that some women are really sensitive to those hormonal fluctuations, others are not. And what I find to be some of the most interesting takeaways from our work in the existing literature is that areas of the brain that show the biggest amount of change pre to post pregnancy overlap with depression circuitry. Now, that doesn't mean everyone goes on to have depression in the postpartum period, but that means that that's a sensitive circuit to hormones. And let's start to model this with, did they have exposure to IVF? Did they have a history of reproductive related psychiatric issues? And how is their brain responding to these hormonal changes during pregnancy? And I think those are some of the most pressing questions in human health.
15:05 - Fungal sugar used to track aspergillus infection
Fungal sugar used to track aspergillus infection
Dima Hammoud, NIH Clinical Center
Researchers in the United States have developed an imaging agent which can track down deposits in the body of the relatively common fungal infection called aspergillosis, which can spell disaster for patients with compromised immune systems. The study - which was carried out on mice - has recently been published in the journal Science Translational Medicine, and it hinges on using a small radioactively-labelled sugar molecule that the fungus can take up and digest but which our own tissues cannot use. As such, it concentrates at the fungal infection site, producing a “hot spot” that a PET scanner can see. Dima Hammoud is the brain behind the breakthrough and she’s at the NIH Clinical Center…
Dima - Aspergillus is actually found everywhere in the environment. We do inhale it every day, but because we have a competent immune system, we are able to eliminate that microbe immediately before it starts germinating and growing. But when those patients with weak immune systems inhale Aspergillus, the spores are not efficiently eliminated and then they start growing and they start invading and become deadly infections. So it's very important in those situations to actually diagnose fungal infections really early on because you want to start them on treatment very fast as soon as possible and that will give you the best results.
Chris - And where does your work fit into that?
Dima - I am a radiologist and my research is in PET imaging, which is short for positron emission tomography. And the reason we were first interested in this is because fungal infections are very difficult to diagnose. So if you do a CT scan or MRI, you might not be able to differentiate a fungus from a bacterium and then you don't really know what to treat them with. Also, you might need biopsies or you need to be really invasive to get those. So that's what kind of prompted us to think of a non-invasive study, like an imaging method that will tell us specifically if there are fungal infections in those patients. And if there are, we can start treatment really rapidly and get better results.
Chris - So almost like a marker that will flag up where they are if they're there and make them go on like a bright red warning light to you, the radiologist.
Dima - Yeah. So a lot of people, especially cancer patients, are very familiar with PET imaging because they get something called FDG PET. And FDG is essentially a molecule. It's a glucose molecule that somebody added a radioactive tag to. And what happens in cancer patients, you inject FDG and then you do the scanning and then you detect where it went because it has a radioactive signal. So what we wanted to do is to develop something similar to FDG, but that thing, instead of detecting tumours, it'll actually go after fungi, like Aspergillus, as I said. because it's one of the worst fungi to infect immunosuppressed patients.
Chris - So how do you target it in that way? What have you exploited about the fungus that means you can do that?
Dima - We looked very carefully at what fungi eat. Fungi are everywhere in the environment and they have to survive. It's not always easy to find food. So as a result, they evolved to be able to use sugars other than glucose, especially those found in plants. And those are really very complex sugars called cellulose, which are like sheets of sugars. So fungi actually dissolve those sugars, by using special enzymes, into smaller pieces. And smaller, smaller, smaller. The last sugar in this reaction is one called cellobiose. So when we started looking at Aspergillus, we thought cellobiose might be a good idea because essentially it's made of two glucose molecules that are very strongly tied together. So much so that humans and other microbes like bacteria cannot break the bond between the two glucose molecules. Only certain fungi, on the other hand, like Aspergillus, can break cellobiose into two glucose molecules because they have those enzymes. So we thought if we actually can take this molecule cellobiose and attach a radioactive tag to it and then inject it in mice that have fungal infections, we should be able to see if it's broken into glucose and FDG by using a PET scanner. The PET scanner we use is actually a small kind of a miniature scanner from the human one. It's only for mice and rats. So what we do is we infect the mice and then we image them after we inject our molecule. And then we had another group of mice that were infected with bacteria, different types of bacteria, and then another group of mice that had inflammation, which is non-infectious. So we injected our molecule, the cellobiose molecule, which has a radioactive tag on it in those animals, and we imaged them and we found that only the animals with fungal infection are the ones that had radioactivity. All the other animals just injected that thing in and it went immediately out. There was no accumulation. So that confirmed our theory that only fungi, specifically Aspergillus in this case, are capable of breaking cellobiose. And that's why you get this accumulation of radioactivity.
Chris - And you're comfortable that that is not harmful when you inject that. It's not going to cause some kind of side reaction or problem for the person who ultimately might end up having it injected into them.
Dima - This is the basis of PET imaging. Anything we inject, including FDG, has to be in very, very small amounts. It's so small that it can never affect any organ or anything happening, any process either in the animals or in patients. FDG for example, it's injected in very, very tiny amounts. And that's the same case with cellobiose.
Chris - So is the basis of this that if you have a deposit of fungi somewhere, because they are capable of metabolising this stuff, they're going to accumulate it. So you inject it, it goes all around the body, but where the fungi are, they're going to grab it, hold onto it, and start to break it down. And that's why you get a hot spot on your PET scan where they are.
Dima - When we inject it, it's in the blood, so it goes everywhere, but wherever it runs into Aspergillus, into a fungus, the fungus notices it and then starts producing that enzyme, breaks it and then takes it in. And that's why it accumulates while bacteria, they see it, but they can't do anything about it. So it just goes away.
21:43 - 'Biblical' tree brought back from the dead
'Biblical' tree brought back from the dead
Sarah Sallon, Hadassah University Medical Center
Have you ever wondered whether science could allow us to bring an ancient species back from the dead? Well, Sarah Sallon and her colleagues in Israel have been doing precisely that. The evidence speaks for itself in the form of a long forgotten plant with Biblical roots. Chris Smith first met Sarah twenty years ago when she had been working on growing ancient date stones - dating back thousands of years - collected from Middle Eastern archaeological digs. Well now, with another ancient seed she found in a university collection from another archaeological dig, she’s “branched out” into a different part of the plant family tree, the one that includes myrrh and frankincense, and grown something else extraordinary…
Sarah - The seed that was discovered was not a date seed like the last time. It was another seed, but we didn't know what it was. No one could identify it. So it was popped in the earth by my colleague Elaine. And up came something that really was very surprising and we didn't know what it was. We sent pictures all over the world and one very clever botanist from Arizona Botanical Garden said, 'Hey, that's a Commiphora'. And I said, 'what?' He said, 'you know, Commiphora, the family of frankincense and myrrh.' I said, oh, that Commiphora. So that's how it began.
Chris - Did the people who dug up the seed realise what it was? And why on earth would it end up in your hands and then going in a pot to grow?
Sarah - The seed was discovered around 40 years ago when archaeologists from the Hebrew University were exploring caves in the Judean Desert. And when you explore caves in the Judean Desert, you often find what they call botanical material, lots of seeds. And the archaeologists sort of take them, put them in little boxes and store them at the university and they don't really bother to identify them. So that seed was in a little box at Hebrew University and I asked the archaeologist if I could have a look at his boxes and he said, sure, take whatever you want. So I went through the boxes and when I was doing it, I found some very nice date seeds and I found this seed that was in beautiful condition. I didn't know how old it was, but it was in the cave. And I took that and I gave it to Elaine and she planted them. So the date story, we already know a few of those came up and this other unknown seed came up too.
Chris - How do you know how old it is? And indeed how old is it?
Sarah - As it was pushing out of the seed, the stalk if you like, it pushed off the seed cap. It was like a little cap on it, it's called the operculum. And she very cleverly took that little seed cap and put it in a little paper bag and gave it to me. And I sent it off to the radiocarbon testing lab in Switzerland in Zurich. Professor Markus Egli whose lab does that. And they came back with a date of about a thousand years ago.
Chris - Wow. And this seed has remained viable in the cave for all that time.
Sarah - Yeah, yeah. But you know, our date seed was much older. Our date seeds were 2000 years old and there's been a publication from Russia where they took seeds from permafrost in the Siberian region of Russia. And those seeds were 30,000 years old and they also came up. So our seeds and really by comparison are not that old. It's just that not many people have been trying to germinate them.
Chris - What does it look like? Is it a tree that's come up and how old? How old is it now? Because you did this a little while ago because obviously you are reporting on what you have now done.
Sarah - It's a tree, yeah. The family of frankincense, and they're called Burseraceae, And the Commiphora, which is a kind of myrrh, is one of that family. But there's actually 200 types of Commiphora, myrrh is just one. So what we did is we took leaves and we tested them to see what kind of Commiphora it was. Was it a myrrh? Was it something else? And the Commiphora are very different. Some of them are quite tall trees, some of them are more like shrubby bushes. They really differ. There's maybe 200 members in what we call that genus. We sent them to Professor Andrea Weeks at George Mason University in the US and she is probably the world's expert on Commiphora. The name Commiphora means giving resin. And she said, well I've got about 109 specimens of this Commiphora from different types, including myrrh. But your one isn't like any of them.
Chris - Is that because she's got what we call extant species things you'd find in the world today. And yours is one that's gone extinct, or isn't grown anywhere anymore. So she just hasn't come across that. Is that one possible explanation?
Sarah - One possible explanation is that it's extinct and it doesn't grow anywhere. And the other possibility of course is that she hasn't got all of the Commiphora in the world and maybe it's still hiding somewhere away and no one's ever collected it or tested it. Because I said there's about 200 species and she's got, you know, samples of maybe over half of them, but maybe it's the other half that she hasn't got. So we don't know. But until today, nowadays in Israel, there are no species like this that have existed not for hundreds and hundreds of years. We know that.
Chris - Would this have biblical relevance then? Given it's in that family and it's in that part of the world? Is there a potentially religious connection here?
Sarah - Well that's the interesting thing you see because in the Bible, in the book of Genesis, there's something in the book of Genesis which Jacob, you've heard of Jacob, he gives to his sons as a present to Pharaoh when the sons are going back to Egypt. And he says, give them a little what he called 'tsori', in Hebrew. And no one ever really knew what it was in Hebrew. It means to drip something that drips. And it was assumed that this was some very valuable resin material. And we know from other parts of the Bible, particularly from the books of the prophets like Jeremiah and Ezekiel, that this tsori was associated with the land of Gilead, which actually is on the other side of the Jordan and is now in the Hashemite Kingdom of Jordan. So Gilead and tsori were connected. There was something, a tree there that produced a resin and it was very valuable. It was also connected with healing and it's disappeared and no one has really ever decided what it was. And we think that maybe what we grew is that tsori. And one of the reasons we think so is because some very clever chemists in France and in Australia tested the resin and found loads of compounds, which are very medicinal.
Do wind turbines affect the weather?
Will - As we ramp up our usage of renewables and a bit to combat climate change, our construction of wind farms grows ever bigger. Wind turbines can be over 200 feet tall with blades not far behind in size as well. Their presence not only slows wind passing through an area, but also creates kinetic movement of air as the blades rotate. So could this affect weather given that much of the weather is just air moving around in funny ways to find out? I put in a call to the founder of the British Weather Services, and author of 'Weather or Not', Jim Dale.
Jim - There'll always be, on a local basis, some kind of effect a bit like your back garden has different effects for the wind blowing in a certain direction, the sun, et cetera. So this is very similar and I think it's such that, yes, there will be some breath of winds blowing, it will create some local disturbances here or there, but I wouldn't at this moment think that it would take it much further than that. I think if you're sitting under these things, you might actually start to feel something that's going on around you, say on a calm day. But I think in the general play of things, in terms of it affecting the actual weather, I would suggest to you that if it does then it's probably quite, quite minimal, but yet to be fully determined, I think is probably the best sentence I can come up with.
Will - Doing a bit of napkin maths, it seems that the average offshore wind farm is about less than half a square kilometre in size. So I don't know how much of a wide reaching impact that could have.
Jim - Yeah, probably a bit more than a butterfly's wings, if you get my drift. There will be some there just like a propeller of a helicopter. You've got to say that if you are in and around these things then there will be disturbances, but not to the point where you're necessarily, you know, being bowled over by these things and it's adding necessarily to the wind velocity. On a stormy day, for example, I often see wind vanes being blown over broken. I say often, occasionally, when the winds get high enough or when, for example, lightning strikes, that type of thing. So it's not a complete and utter positive and you know, in terms of where they stand and what might happen to them or around them. But at the same time, as I say the positives far, far outweigh the negatives as far as we know at this moment in time. So I think we press on regardless.
Will - Yeah, I think you echo the sentiment of someone on our forum called Bored Chemist who says any direct effect will be tiny. The reduction in CO2 might be significant and I think that trade off to me personally is worth it.
Jim - Yeah, in life generally there's always a trade off between the good, the bad and the ugly. And as long as the good outweighs the bad and definitely the ugly, then you're going in the right direction. And that's what science is about. Good science, positive science is about moving in that direction for the benefits of all. And that's what I think we've got in this case so long may it live.
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