the latest headlines from bbc news: the second impeachment trial has begun in the senate. the leading democrat says the case against mr trump is clear and his life say it is about freedom of speech. scientists investigating the origin of the coronavirus do not believe the virus escaped from a lab cannot say exactly where it had come from. some suggest it may have come imported by frozen food. and entering the orbit of mars. hope is the first from the arab world. only four others have made a successful trip to the red planet.

it is now time for click. this week, bioprinting cells, talking to strangers, and perfecting your posture. welcome to click — hope you are doing ok. you probably don't want to hear this, but we are now almost coming up on a year of video calls, zoom meetings, and teams chats. in that respect, at least, i think the world has adapted quite well. unsurprisingly, a lot of innovators have lept

to the chance to invent a whole range of video call accessories. and my good friend lara lewington is wearing one now. can you spot it? what could it possibly be? these are the periphery smart earrings. not only do they help you get your top half dressed up for a video call, but they also provide sound directly into your ear just behind the earring, and there is a microphone just here, as well. it means you can make phone calls or video calls and communicate through these. i'm no expert — i would say they are a little on the big side, but they do match your frock. almost, and they come in different designs. but, as you say, they are chunky and could do with being made smaller. but the idea is not bad. and talking about not—bad ideas, how about this? what's that? this went viral a month or two ago. it turns out one of the most awkward parts of a video meeting is trying to leave it. i don't know if you have been there, but everybody waves,

and with their other hand they hit the leave meeting button, then it turns out that you haven't really left the meeting, and then you need to click the confirm button that you want to leave. this inspired one creative technologist to create the zoomout. to leave a meeting, i pull this... he's gone. you know when you're talking to somebody and you say goodbye in person, and then you end up walking in the same direction? i hate that. exactly. it's like that, but every hour, when you're doing calls all day, you are trying to leave and you say goodbye, and you're fumbling for the leave button. this is brian moore, who created the zoomout. of course we had to make our own. so stephen beckett downloaded the plans that brian put on github, got handy

with the printer, and here is the result. here you go. a pull cord connected to a circuit board that sends a message to your computer to end the call. simple and effective. it's a race. one, two, three, go. you don'tjust have to make these things for yourself, you can share them with the world on the internet so you can go viral with these things. i feel really good comedians, they make a joke about something that everybody thinks isjust something that they experience, but then because they laugh at it because, well, everybody experiences it. the same thing goes with this. i didn't think that many people would — this is certainly something that i experience. it turns out that millions of people who watched this felt the same way. i never know — i'll make

something and put it out in the world, and one person will see it, and say that's dumb then sometimes, i will make it, and put it on the web, see what happens, and suddenly blows up and i'm like "wow, i can't believe it." it just struck a chord, no pun intended. what are some of the other crazy things that you have built? i have built a scooter that is powered by screaming. it's powered by anger. it was for angry birds. it's a scooter with a microphone on it. it didn't work unless you screamed. the lourder you screamed, the faster it went. something i am working on that i have not mentioned is this a polaroid. when you take a photo of somebody, it actually prints out a reverse image recognition photo of them off the internet, which is terrifying. it's a really scary thing. i tried taking a photo of my wife and i printed out a photo i had taken of her seven years ago, because it was on the internet somewhere. brian, can you keep these dumb

projects coming, please? they are brilliant. i can try. with covid, all i'm doing is sitting at home and making these things. good, you're back. yes, iam. now we're going to talk about stem cells. stem cells grow from one type of cell into any type of cell in the human body. for researchers, controlling that process is proving difficult. but now one company in cambridge claims to be able to reprogram stem cells to produce any other type of human cell in large quantities. it is part of a growing trend to bioprint elements of the body. the ability to repair damaged cells and tissue in the body is the focus of the field of regenerative medicine. over the years, we have seen bioink to print tissue,

3d printed body parts and bones being grown from a person's own stem cells. innovations around stem cells, the building blocks of our bodies, offer exciting potential. typically, these cells are extracted from a blood or skin sample in small amounts, but one company is working on producing any type of human cell in industrial quantities. hello, how are you? thank you for having us in your lab. this is one of our molecular biology labs, and here we create what is called gene cassettes, and we create — engineer cells, essentially. here at bit.bio an interdisciplinary team has created a new technology. it enables the precise reprogramming of entire cultures of stem cells into any cell type on a vast scale. founder and neurosurgeon mark kotter is combining coding and biology to create a deeper understanding of the genetic engineering a result.

we have taken a slightly different angle on biology. when we look back over the last 30 years, it seems like you can look at biology a little bit like a software. and that means that there is a possibility to, you know, reprogram, reboot a cell with a new programme. and our technology allows us to do this extremely efficiently. and that has really opened a completely new way of thinking about manufacturing and precision engineering of cells. we keep them in incubators here, as all other cells that are grown outside the body. they need certain oxygen

level, carbon dioxide, and temperature. and when — once we make the — design the cell type, and when — once we make the — desired the cell type, we can actually freeze them in small test tubes, in tubes, and you can send them to the customer in a frozen format. these cells could then be used for patient therapies, but also to study rare diseases or discover new medicines. the golden standard in the field is to use primary cells, which are isolated from human organs. but, as you can imagine, the difficulty there is that the donors are very scarce, so it is very difficult to get these primary cell types. bit.bio aims to bring a new gold standard to the field. we can create more true cell types that behave like primary human cells that you would find in the body. using these mature cell types for drug testing could yield much better results and eliminate the need

to test on animals. every disease, every condition, starts with a problem at the cell level. it is the cells that actually go wrong. if you want to create medication, drugs, then you need to understand what is happening in order to be able to design the right drugs. and i willjust pull out an example. for example, alzheimer's disease, you know, there has been a lot of effort to create drugs. they haven't been very successful. traditional drug discovery, would use animal models and cells to model, you know, a condition like alzheimer's. but the problem is that mice don't get alzheimer's, so you have to do something to the mice so that they then present with something that looks like alzheimer's. then you create a drug to treat the thing that you have created. and so this is where

we bring a unique solution. we can create human brain cells that actually are affected by alzheimer's. what this allows you to do is then to use, you know, target your research and drug discovery against the actual condition. having access to millions of high—quality human cells could help advance other technologies. a team in south korea have developed this bioprinter that could help heal diabetic foot ulcers. a photo of the ulcer is uploaded to the machine which matches the size of the ulcer with biomaterials. this helps with the healing of ulcers and wound closure which could lead to amputation if untreated. these could be aided with the manufacture of human

cells on an industrial scale and could revolutionize the capabilities of regenerative medicine. hello and welcome to the week in tech. it was the week amazon founder jeff bezos announced he was stepping down as chief executive. he will become executive chairman, and will be replaced by new ceo andy jassy. and the latest rocket prototype from elon musk�*s spacex had an explosive landing. engineers said the test flight provided valuable data. and call of duty: warzone has banned more than 60,000 accounts in one day for cheating. publisher activision says it is improving its own anti—cheat software. and ai—powered traffic cameras in australia could soon get an upgrade. existing smart cameras detect offences like mobile phone use. now, instead of being hit with a fine, drivers will be warned by a roadside display. continuing the road theme, swiss researchers have

developed a computer vision system to allow motorcyclists to take bends more safely. using cameras and a display, it calculates the optimal trajectory and speed through a curve. and finally, everybody�*s favourite and/or terrifying robot dog now has an arm. spot, developed by boston dynamics, can now perform tasks like tidying up, opening doors, and writing massive messages in chalk. it can now also be operated remotely. good boy. i've been working from home now for almost a year, and i've done a lot of slouching. and i started getting worried i might be doing myself some harm. i've also been bombarded with instagram ads for this gadget that makes you sit up straight, so i thought i'd give it a go. this is the upright go 2, and you wear it at the top of your back.

it comes with sticky pads so that you can stick it to your skin, or you can wear it on a neckband. i prefer the glue. once it's in place, you tap the button twice to calibrate. then, if you lean forward, it will vibrate, reminding you to sit up straight. that's all there is to it. the app records how long you've been slouching, and how long you have been upright. in my first experiment, i turned it the vibration off so it would just record a passive reading. that was hard to do, because once you're conscious you're wearing it, you tend to sit more upright, anyway. but, in my first two—hour stint, i was uprightjust 5% of the time. for the other days, when i was sat at my desk working, i had the vibration switched on. as you would expect, if i leaned forward, it would buzz. after a few seconds, it would buzz. there were times where this got a bit annoying, because there are lots of times where you lean forward, even if you're resting on your elbows with a straight back, or you get up to make a coffee, and you're leaning over the kettle.

at those times, it would be vibrating, telling you you are slouching. for that reason, i did not wear it all day every day. but if i knew i was going to do an hour or two stint at my desk — perhaps editing a video — i would put it on. i did get used to it, and there were times where i completely forgot i was wearing it. at least once i showered with it on. thankfully, it still works. after using it a few times, those stints where i was wearing it, i was managing to get 80—90% of the time upright. i'm lucky i have never had serious neck or back pain, but i wonder if there are health benefits to this. the company makes no health claims on its ads on instagram, but it does make health related comments on its website. so, i spoke to ashleyjames from the uk's charter society of physiotherapy to ask if there is anything wrong with slouching. absolutely not. there is nothing wrong with slouching in moderation, just as the same there is nothing wrong with sitting up perfectly straight.

what we know is there is no right or wrong position to sit in. there are only positions that are held for too long. i've seen those posts on social media that say if you use your phone too much or you sit badly in a chair, you are permanently changing the shape of your necks and spine, is that true? yeah, no, there is no good evidence that sitting in any one position will permanently change the position of your spine. the key thing is movement and not to be sat in any one position for too long. what i am hearing is it is fine for me to work in bed all day? everything in moderation, i wouldn't suggest working from the sofa or the bed all day, not because it is inherently bad, but because it would reduce our ability to move regularly, and that might lead to some pain and discomfort. the company told me it doesn't make health claims for its products but its research shows that people do sit up more when they use it.

no surprise there because it buzzes every time you slouch. one thing i notice is it doesn't buzz if you lean backwards. positions like this are not ok but you can sit really badly backwards in a chair and it will never vibrate. purely from a cosmetic point of view i have enjoyed wearing this, i see in the shops with the mirrors, i see myself slouching over. but i can imagine, when the pandemic is over and i get to go to some posh events, i might wear this to remind myself to sit up straight and keep my shoulders back. that was chris. and this is chris. watching it made me want to sit up straight. it does seem it is more about movement than posture? that was certainly the view from the physiotherapist. as long as you're not spending all day sitting in one position and moving around a bit more, then that may be more comfortable for you. that makes sense, i've never been someone who suffers back pain but the time

i have had a sore back, a sore coccyx has been when i have been on a flight, and haven't realised i had been sitting in the one position. it makes me want to carry on moving. i think that is good advice. maybe do some desk yoga, some dance routines. one tip is rather than spending maybe £100 on a posture trainer like this, if you already have a smartwatch or fitness tracker, they usually tell you once an hour, you can set it to buzz, to remind you to get up and move around. i feel that is the same thing. to stand up every hour for a number of minutes. another good thing to do as well, it you moving. chris, thank you for sitting up and paying attention. now, one of the things we missed in lockdown, some of us probably missing more than others is meeting new people.

now, i don't mean dating, ijust mean for a chat with somebody different, because many of us have been speaking to the same person or people for the last year. i am saying nothing. well, i've tried platforms that aim to change the conversation. meet marguerite, who lives in surrey. i have six grown—up children and 18 grandchildren and 15 great—grandchildren. some of them live far away, others are working old day and they cannot always come and visit me. but life can be isolating, especially in these days of lockdown or restrictions. so, one of marguerite�*s daughters went looking for a professional companion for her. now, meet sue, a freelance script writer who lives close to marguerite. it was marguerite�*s name that kind of caught my attention. i asked her about her name and she started telling me her history and mentioned that she had once upon a time been a professional ballroom dancer.

yeah, i was very interested in her life and she was interested in what i was saying to her. the app was originally launched to provide face—to—face short spells of company from pre—vetted companions for an agreed fee. it may have been the start of a beautiful friendship, though? during lockdown times, many like sue and marguerite have chosen to switch to the apps online meeting space. one of my hobbies is writing. so, hearing stories is fascinating for me. i love it. and one thing i like about the whole sort of companions app is the structure. if you go around to help somebody, and then they say could you just, and can you just, with the app, you are able to have boundaries, i think, and that's quite important. sometimes you can open up to people and not tell your family certain things, which i think is very

enlightening. with the lockdown, life is very boring and there are lots of people here where i live, they are very lonely, lots of them. it has given me a lift in life. which i was stagnating a bit, ithink. the matching up process sounds like online dating? yeah, yeah! it is all that. lisa, who used to be an advertising exec for amazon uk thought up the idea after a skiing accident. we wanted to create something that is going to be for us. we need this, we need to look after our parents when we are older. we started to break it down, what technology do we need? what competitors are out there? what do they have, what don't they have? how do we make it a seamless journey for everybody? companions is not the only platform that can help you meet

people for a bit of conversation at the moment. quarantine chat launched last year and the idea is that it randomly puts two people together from anywhere in the world for a i—to—i phone chat. we are about to connect you to someone else, hello? hi. how's it going? i am doing pretty well. i'm a filmmaker and there was a big film festival two weeks ago, and a lot of my friends went... now restaurants, can be at 25% capacity. . i'm craving wide space at the moment, so, big mountains, and so on... i found somebody was at the party who had just tested positive... putting it to the test, a few of the the calls i signed up for did not happen, but i did manage to make a friend in japan. what has been the greatest high for you? mostlyjust reading books.

and i'm interested in people. the app matches you with someone who speaks the same language and who is awake at the time, operating via another app called dial up, no personal information is shared and calls are made using data. it now has 10,000 users globally, and although they are not pre—vetted, there is a feedback system to report anything untoward. the idea for the app had come from one of its co—creators' own experience of being quarantined. there is a lot of benefit to just getting out of your own head and listening to somebody else�*s stories, and having someone listen to you. it is just the two of you on the phone, not a group chat room or anything, it is just the two of you and you both want to talk and you are listening to each other, there is very comforting.

it helps you feel very connected. meanwhile, our original pairing, sue and marguerite are looking ever stronger. got many more stories that i would love to hear, we might even write a book together. i think we are planning on meeting up soon again, are we, marguerite? yes, we are. we can talk about the weather. how interesting. i've always felt awkward talking to strangers, but how was it for you? it's funny, actually. of all the things i have missed over the past year, it had never occurred to me that i would miss meeting people from different places. but actually doing this, it did feel quite refreshing. awkward to start with but then you settle into the chart. something new for every one to try. looks like we have all tried something new this week. that is it from us for now.

and as ever, you can keep up with the team on social media, find us on youtube, instagram, facebook and twitter on @bbcclick. see you soon! bye— bye! bye— bye. hello. the cold snap across the uk continues. and no sign of anything milder for the remainder of this week. very cold nights ahead and some pretty bitterly cold days as well. a subtle change for today is that the wind will be lighter than it has been on monday and tuesday, though perhaps it won't feel quite as raw, but it's still an easterly or northeasterly wind. still some chains of showers being fed in, some making their way a reasonable way westwards. some of the heaviest snow on wednesday possibly

for kent and sussex, the southeast of scotland and the northeast of england. as we move overnight wednesday into thursday, i've got the pressure pattern on behind me, notice how the isobars open up. the wind becomes much lighter. now, as i said, that wind has made it feel very raw through the early part of the week, but for very cold nights, what you need are very light winds, and that is what we will have to take us into thursday morning. and that's important because at the moment, that's indicating signs that for some areas to the south of the uk, these are the temperatures of the towns and cities. we could have the coldest night in around a decade for some of the suburbs of london, for example. thursday, dawn, icy but with a lot of sunshine. there will be quite a bit of fair weather and largely light winds, a few north sea showers. temperatures, well, scraping just above freezing. towards the west, perhaps three degrees for belfast and plymouth. notice a little frontal system trying to push its way in here. this is the first signs of something a bit milder trying to approach from the atlantic. friday, it still

looks like it'll be the high pressure in the east and the cold air, though, that will dominate. we could see some more organised snow showers for a time running into the northeast of scotland. towards the west, i think advancing cloud through the day turning any sunshine hazy, but 4 degrees in belfast, 5 degrees in plymouth. some signs of something milder trying to head in. subzero, though, further east across the uk. and then for the weekend, it's that classic battleground that we so often talk about — high pressure in the east pushing the cold air our way, low pressure trying to come in from the atlantic and bring in something milder. at the moment, it looks like by sunday, we could start to see some significant improvement in our temperatures. but before that, there is the possibility of some further snowfall, but this time pushing into the west as we begin our transition.

a very warm welcome to bbc news my name is mike embley. senators vote to go ahead with the second impeachment trial of donald trump, rejecting suggestions the preceedings are unconstitutional. mr trump's legal team claim the trial is all about freedom of speech and politics. we are really here because the majority in the house of representatives does not want to face donald trump as a political rival in the future. the world health organization investigation concludes coronavirus did not originate from a lab in china but can't say where it did come from. rendezvous with the red planet — the uae�*s historic mission successfully enters orbit around mars. # some day we'll be together, yes we will, yes, will...#

and mary wilson, a founding member of the supremes,