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Biological Safety Cabinet (BSC): How it Works to Protect You

This video shows you how biosafety closets can protect you provide protection for laboratory staffs makes and the environmental issues, At the same time reduce the risk of exposure. Have an in-depth understanding of how the biological safety locker operates, and at the same time follow the established laboratory refuge running project, It can prevent your work from being polluted and protect you at the same time. If you use the correct one, a installed correctly and showed biological refuge locker will be implemented by biological materials in you, Including virulent pathogens and recombinant DNA process to provide personnel, environment and concoction shelter. This video describes a free-standing Class II type A2 biological refuge closet or BSC. BSC includes: HEPA filter for exhaust and quantity aura. acting desk. Window on the countertop. airfoil. Front and back into the style grid. Static influence chest. BSC’s air filtration organization can thwart potentially contaminated breeze from returning to the staff. The breath flows from the window into the front air intake frame, transfers through the static persuade casket, and then spurts into the HEPA filter. 30% of the filtered aura will be exhausted. The remaining 70%, after being filtered by HEPA filter, is recycled back to the work area. In order to ensure maximum protection when using biological security closets, here are some necessary tips. 1. Before starting your work, if the safety cabinet is closed, you must turn it on and wait at least 15 times. Second, establishing the internal working seat from “clean to dirty”, and effort from one direction to the other to prevent cross-contamination. 3. In your work area, neighbourhood the chair at a cozy elevation and in the middle of the manipulate province. To ensure that you can reach everything you need in the cabinet without feeling uncomfortable. Please keep in mind that you must operate at least ten centimeters in the biological security cabinet. In order to better to ensure that the airflow is not agitated, too many pieces should not be placed in the biological security board. Too numerous entries in the biological security locker may block the air grille. The airflow may also be disturbed by sudden or cleaning actions. Slow, direct flows work best. Too many walkers can also cause problems and should be minimise as far as is possible. If this really is unavoidable, delight continue pedestrians at least one rhythm away from the biological safety board. At the same time, satisfy check the surrounding entrances and shows are responsible for ensuring that they will not disturb the airflow of the safety cabinet. When you finish your work, any reusable parts must be erased with a disinfectant before they can be removed from the biosafety arrangement. Take it out of the whole cabinet. Then, the inside of the biological safety board should be sanitized according to the recommended contact time of the appropriate disinfectant. To ensure thorough disinfection, a second disinfection method can be adopted. In short, the use of biological refuge closets should comply with a number of best rehearsal principles. Tells discuss it one last-place meter. The labor sphere is at least 10 cm in cabinet ministers Do not block the front and rear grilles Too numerous items in the cabinet will disturb the airflow Arrange the cultivate country in order from clean to dirty Keep your pushes illuminated and straight Minimize walkers within one meter of the safety cabinet Placing the biosafety closet away from doorways and shows facilitates maintain airflow Thanks for watching, please be safe! National Biosafety and Bioprotection Training Program Sara A. Koupu, Ph.D. Altea Kapoor, Ph.D. National Association of Health U.S. Department of Health and Human Services Deborah E. Wilson, Department of Occupational Health and Safety, Research Service, Doctor of Public Health, Certified Biosafety Expert Herbert B. Jacobi National Organization of Health U.S. Department of Health and Human Service In the medical land, Kedan Mammersting, Ethan M. Taylor, Ernie Branson, Joey Jackson, Farah Michael Blaney, Northwestern University, Ph.D. Andre Hull, Ph.D. Actor Adam Smirian Sears Altea Kapoor, Ph.D.( Still photo) Assistant screenwriter Serast Crenshaw Narrated: Altea Kapoor, Ph.D. Video produced by Sheila Smith Music: Instances, safety measures and recommendations shown by Jonathan Klein in this video It does not involve all potential health and safety issues associated with the use of biological security lockers. The biosafety closet in your laboratory may be different from the pose shown in this video. Please take the time to understand your biosafety cabinet, its design and correct operation. Ever wear appropriate personal protective rig( such as eye protection, lab coatings and suited mitts) 65 00:04: 57,297 –> 00:00: 00,000 so that you can use, handle or supermarket bio-hazardous products in the laboratory.

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William Shih (Harvard) Part 1: Nanofabrication via DNA Origami

my name is William Shi I’m an associate professor of biological chemistry in molecular pharmacology at Harvard Medical School Dana Farber Cancer Institute and the beast’ Institute for biologically inspired engineering it’s my pleasure to share with you today some recent technical advances in the field of structural DNA nanotechnology from my laboratory and those of my colleagues we’re all familiar with the biological role of DNA as a information repository principally for coding for protein sequence and for regulation of protein expression and I’m not going to speak about that at all today instead I’ll be talking about using DNA itself as a building material and harnessing that in order for us to construct nanoscale objects for example shown here is an electron micrograph of actin filaments that are about seven nanometers in diameter and below we can see this peculiar pac-man shaped object this is a structure that was built entirely from DNA and we designed it for the purpose of taking bite-sized chunks out of the actin filament well this project hasn’t yet been successful however hopefully this image drives home the complementarity between the dimensions of our design DNA nanostructures and biological macro molecular complexes so I’ve been working on this field for over a decade now and I’m continually surprised by advances in the field I have these preconceived notions of the limitations of DNA and they’re always shattered by the latest new discovery and today I’m going to be sharing with you in the first two sections respectively two recent developments that enable us to design and assemble DNA nanostructures of the size and complexity of this object shown here about 30 nanometers in diameter one of the most important goals for DNA nanotechnology is to self assemble ever-increasing objects of ever-increasing complexity over time for example is it possible that within the next decade or two that we can self-assemble objects that are let’s say a thousand times as complicated that have a thousand times as many unique components as the object shown here a second question is what are these things good for and in the third part of this lecture I’ll be discussing some applications in my laboratory as tools for molecular biophysics and tools for future therapeutics where we think these objects might prove useful we’re inspired from natural systems we know that they can carry out many amazing behaviors they can build they can adapt they can heal they can reproduce and these are capabilities that human technology struggles to reproduce on any kind of length scale but what’s especially remarkable is the ability of life to carry these out on the molecular scale so for example here on the left is a picture of a ribosome and this is of course the machine that’s about 25 nanometers in diameter that takes information encoded in messenger rna’s and then translates that into a specific sequence of amino acids to produce a polypeptide quite amazing machine on the right we have the t4 bacteriophage it’s a bit larger in length scale we can see that the viral capsid itself egg capsid is about 100 nanometers in diameter so it looks like a little nanoscale hypodermic syringe that box onto the surface of its pectoral host and then injects its DNA cargo into the cell against an osmotic pressure gradient of course what makes this all possible is that living systems have invented molecular manufacturing and they’ve come up with a very robust and clever way of doing this they of course synthesize these biopolymers they could be polypeptide chains poly nucleotide chains that end self-assemble into the desired structure now if somebody asked you about ten years ago would it be possible to generate an object of this complexity using some kind of human based technology most people would have been skeptical and yet I’m going to show you a new technology DNA nanotechnology developed in the last especially with advances from the last ten years that now make it possible for us to self assemble the program boy structures of the same kind of complexity as you see here not yet of the functional complexity but nevertheless we think this is a encouraging first step because there along the pathway to this kind of we first need to master structural complexity we’re going to be using DNA as their building material and we know that DNA very similar to proteins and other macromolecules from life are very complicated molecules there’s many different atoms but it turns out the key point for DNA nanotechnology is that the robust base pairing properties of DNA allow us to abstract away those chemical details which is going to make the act of designing the now structures much simpler in fact there’s only three characteristics of the DNA that we need to remember for the purpose of DNA nano construction one is that it’s a ladder with antiparallel strands secondly there’s a right-handed twist for B DNA and we need to know that the twist is around ten and a half base pairs per turn turns out we can switch that around a little bit and finally we need to know that a pairs with T C pairs with G and anytime you deviate from that pairing you’re going to destabilize the structure and it’s because the propensity of DNA to form this very regular structure enforced very strictly according to this watson-crick base pairing that gives us its power in being able to generate these large structures with very little design work the father of the field of DNA nanotechnology is Ned Seeman and NYU he invented this field about 30 years ago his training is as a crystallographer and the way he came up with the idea is as follows he was sitting in the campus pub one day just drinking his beer and suddenly what popped into his head was this woodcut from MC Escher he had been collaborating with some of his friends on DNA Holliday junctions and he had a Sarika moment why not replace the flying fish with DNA Holliday junctions the notion was that if he could rationally design a porous crystal out of DNA and then he could take the target protein he’s interested and then dock that into each unit cell in history of stereotyped orientation then he able to be able to impose that crystalline order on the target protein and therefore make the x-ray crystallography ER for these large macromolecule that are otherwise difficult to crystallize he’s been working on this problem for over 30 years it’s an important goal and he’s made some interesting progress I’ll have more to say about that in the third segment but in the meantime he’s had some interesting landmark successes the first really noteworthy advance that he reported came out in 1992 or so in nature this is a DNA cube where each edge of the wireframe cube is two terms of a double helix each face is a circular strand of DNA and the entire object has dimensions of about ten nanometers so the first time I think people saw this they thought well this is really cool but that doesn’t look like biology to me and what I hope to convince you today is that this is in fact an extremely powerful technology yes it’s fun but it’s actually potentially very useful as well for many different applications of course if we’re building from DNA strands and we’re just making double helix season that’s boring the power of DNA nanotechnology is that we can build with branched junctions with the previous example the cube each one of those vertices is the 3 branch Junction but it turns out the most powerful motif so far in structural DNA nanotechnology has been a 4 branch Junction a Holliday Junction so on the upper left here we have a schematic using simple letter notation of the strands so you can see the science strand starts v prime c cg g goes to its 3 prime end and if you look closely at this you can see that there’s four different sequences and they have the proper sequence complementarity in order to generate a Holliday Junction that actually is a mobile it can’t branch migrate due to its sequence and we know from structural studies that this object likes to stack into two double helix E’s that are connected at a joint and it turns out this is really the building block that’s been the most fruitful for DNA nanotechnology so the idea is as follows if you only have one Holliday Junction now you have two HeLa C’s that can wobble around in order to fix those two HeLa C’s to make a rigid building block we do is we simply introduce a second holiday Junction down the stream and now when we fix that those two double helixes with two Holliday junctions we have that rigid building block that we want now with four sticky ends the next step is to build two versions of this building block in this example we have a red one we have a blue one and we design the sticky ends with following complementarity in this example so let’s say we make the sticky end on the upper right-hand side of the red block and we make that compatible with the lower left-hand side of the blue block and so on and so forth in order to create this kind of checkerboard fashion hopefully you can see that we would be able to self-assemble these two bricks into an infinite two dimensional lattice as shown below I don’t have the experimental images for this but it suffice to say that this method actually worked it’s quite amazing you can design a two dimensional crystal the step after this would be to say well instead of just two bricks two tiles what if I had ten tiles or what if I had 100 tiles can I now make non-periodic structures that are highly complex just with self-assembly tiles and unfortunately nobody has really demonstrated this method extending this particular method to hundreds of tiles although what I’ll show you shortly is one method DNA origami that can achieve this kind of complexity and in the second segment something called single-stranded bricks that can do something very similar to what I just described the method of DNA origami is a particular flavor of structural DNA nanotechnology it was developed by paul rodman at Caltech he published this in 2006 and the basic idea is as follows so imagine you have a long single strand of DNA the seven thousand base genome of the m13 bacteriophage that’s the gray strand in this animation we note the sequences and based on that known sequence we chemically synthesize hundreds of short oolagah nucleotides that are 20 to 60 bases long that a program by Watson Crick complementarity to pinch that long strand into a parallel array of HeLa C’s after heating everything up to about 65 degrees centigrade and then cooling down to room temperature over the course of an hour at the end of the assembly you end up with this parallel array of double helixes where adjacent double helixes are held together by these Holliday Junction crossovers that I described to you a couple slides ago so this is a half crossover and then here we have a full DNA crossover importantly what you just saw was an animation not a simulation in fact we have a very poor understanding of the order of events of folding these objects we just know that if we program them in a way where all of the scaffold ends up base pair de staple strands then we have an extremely high probability of forming the desired structure so it’s a very active area of research for us to try to understand better the mechanism of folding and we we hope that will actually help us to design more complex structures in the future so paul rodman use this method in 2006 to make structures such as this disc with three holes it has dimensions about 100 nanometers by 100 nanometers by two nanometers this is atomic force micro graph the example in the upper left hand corner represents in size just part of the upper lip of the objects this is quite large by macromolecular standards it’s like we have two ribosomes worth of molecular silly putty that we can mash into any desired two-dimensional cookie cutter shape one of the very interesting things that he pioneered was that he developed a way to make this DNA origami where he made each one of the staple strands in two different flavors so one flavor just made the structure as you saw the second flavor had the identical sequence but had a surface feature a dumbbell that’s sticking out of one of its ends and so what that means is anytime he used the original flavor and he added it to the folding mix then you’d get a plain vanilla DNA origami surface at that location but then if he replaced that sequence with the longer sequence the one with the feature now you get that same shape but a bump over that feature and in that way he can see that this rectangular DNA origami could be treated as a molecular breadboard where let’s say it has 200 different positions we can decide at each position whether or not we want to create a bump or have no bomb in the fact we have something that’s like a bitmap and we can create new patterns simply by repipe heading different patterns of the no bump and plus bump strands for each one of the locations so for example here we can see that he’s designing something that will say DNA have a little picture of DNA these structures actually become very sticky at the ends because they have lots of blunt ends and then they’ll make a continuous ribbon that says DNA you can see that he made a map of the Americas he’s a very humble guy so he apologized the rest of the world for stopping at the Americas but DNA’s a little bit expensive so he stopped at the moment maybe by now he’s made the rest of the world and you could you could program them to link up in specific ways and in that way you can self-assemble two-dimensional crystal and objects so what about getting to 3 dimensions as I alluded well we can get our initial inspiration from macro scale paper origami where we know we have were quite familiar that if we fold flat paper in many ways we can get quite intricate three-dimensional shapes so this is the famous crane and if you’re really diabolical like Robert Lang then you might note that if you can fold these papers in very and especially intricate ways then you can make incredibly complicated objects that we we can see some examples of here now nothing I’m going to show you with DNA is as complicated as this but again as I mentioned one of our goals is to scale to ever increasing complexity so we hope that someday we actually can self-assemble DNA into objects of this kind of complexity so that group in Denmark that I’m it just mentioned van der Senor Kim’s hotel they were able to design that m13 to fold into six different sheets and then they program those six sheets to fold up into a 3-dimensional box with a hollow inside they designed a lid that can open in response to some kind of molecular key so this was the first example of three-dimensional hollow in your origami so where my group wanted to contribute was to make solid three-dimensional you’ll be near origami structures and the idea is as follows so first of all we know that we can curl up DNA due to the he licit e of the DNA helixes and i’m going to go through a little thought experiment just to give you a flavor of what this is about so here we have on the far left three double helix e’s that are arranged into a little DNA origami you can see if you look closely they’re connected by those Holliday Junction crossovers to keep the Gila C’s parallel and in this arrangement it’s making a flat sheet of three HeLa C’s so now imagine what would happen if we moved these crossovers on the top two base pairs to the left then that’s going to move that double helix behind the plane of the page and likewise if we move those two crossovers two base pairs to the right that’s going to move that double helix in front to the plane of the page the take-home message here is that simply by shifting around the position of those crossovers with respect to each other we can achieve curvature of these DNA origami sheets along the axis of the double helix C’s so that’s the first key so now let’s extend that and build an actual solid three-dimensional structure so here we have another representation of edenia origami or each one of these cylinders represents one of those double helix e’s so it’s similar to the example in the upper left but now just rotated into this orientation so this would represent the pattern of the scaffold running through those HeLa C’s but for the purpose of this explanation I’m going to leave that invisible it’s there I’m just not going to talk about it that or the staple strands and so what we’re going to do is we’re going to shift around the position of those crossovers so now these HeLa seats no longer prefer to be planar but instead prefer to curl up into some kind of specific geometry and in this example what we’re doing is we’re trying to curl up the structure into a corrugated S shape furthermore anywhere where we have the orange sheet that touches the white sheet touches the blue sheet we’re routing those staple strands through those interfaces so for example we might have a staple strand that starts seven base pairs on this helix then go seven base pairs here seven base pairs seven base pairs seven seven base pairs and then that way if the structure forms the way we intend it to it should be highly cross-linked by the staple strands that are traversing the different Gila Seas so it looks good on paper okay what happens in the test tube when we tried it and perhaps you can say of course when we threw all the strands together and tried to fold the object then it didn’t work we got a pile of molecular spaghetti that we could see under the electron micrograph but we didn’t want to give up and eventually Android eats in the group came up with a key insight which is it’s not that these three-dimensional objects now are unstable thermodynamically simply they’re more difficult to achieve kinetically and so what we found is that we can only get appreciable yields of these objects if we folded them instead of for an hour going from 65 room temperature if we folded them for more like a week then we could start to get appreciable yields of the objects ranging from 10 to 50 percent yield so we can see here one of the objects that was built by Shawn Douglas instead of three layers it was with ten layers and then we have the electron micrographs below we can see that we get a close resemblance between what we observe in the electron micrograph and the projection orientations of our design structure this is work that we published back in 2009 in the meantime our group and others have been hard at work trying to improve the method so the important thing here was that we we could get something to fold it all and now we’re trying to get better yields improve the folding times so there’s been a couple of important discoveries since then one has come from Hendrik deetzes lab in Munich where they’ve discovered that these structures tend to have a favored temperature which they film faster than the other temperatures so instead of spending the same amount of time at 65 degrees down to room temperature for example the structure maybe folds faster at 50 degrees centigrade so what they found is if they do most their folding at 50 degrees centigrade then they can get it to fold maybe an order of magnitude faster which makes a lot of improvement for a lot our lives as a scientist designing them they also suffer less thermal damage with a slower folding ramp we’ve also learned some details about how to design the strands the crossovers the breakpoints that I don’t have time to go into in this presentation but I encourage you to look at some of our publications if you want to see the latest discoveries on how to make this process work better so now I’m going to go through a panel a gallery of different objects built using this method by our laboratory to give you a flavor of the generality of the method so the example on the top is what I just showed you we call it the model if it was built by Shawn Douglas you might say that it looks a little bit like a nano scale crystal honeycomb or a crystal but it’s important to keep in mind that every element of the object is associated with a unique sequence and therefore is independently addressable this is quite different from most nanoparticles that we see in synthetic nanotechnology today the example on the bottom was built by Francisco Gulf we called the genie bottle we called it that because in one version not shown here we only folded part of the m13 scaffold and the rest of it was coming out of the lip of the object kind of like wisps of smoke these are all 20 nanometer scale bars so here again 29 meter scale bars on the left is an object built by Shawn Douglas we called the square nut it has a 7 nanometer hole in the middle it has a front end and a back end and if we make the sticky ends on the front and compatible the sticky ends on the back end then we can self-assemble filaments that are somewhat reminiscent of actin filaments or microtubules although in this case they don’t yet demonstrate any dynamics they’re just equilibrium formation of these long polymers on the right is the object built by Tim little we call it the rail bridge again every cylinder is one double helix and we can see as we go through cross-sections of the object we have a different arrangement of double helixes and we can understand from this example that it is kind of analogous to sculpture that you could imagine the sculptor begins with a solid block of marble in our case these parallel rays of double helixes and in design space we’re chipping away at that solid block until we achieve whatever three-dimensional structure we actually want in relief once we have our final design then we what we’re doing is we’re compiling that three-dimensional structure into a series of DNA strands that are going to self assemble with the m13 scaffold into that object here’s an object built by during hug burg when here’s in the group we call the slotted cross I’ll have more to say about this object in the next slide this is another cross object we call the stacked cross built by Hendrick Dietz again these are all 20 nanometer scale bars this one looks a little bit like stacked molecular celery we even designed a little molecular cavity on the top where we initially imagined we could host protein guests on the inside of that cavity so let’s take a closer look at that slotted cross from yarn harbor so here what he’s done is he’s generated animation where he stylized the routing of the scaffold strand through the structure it’s designed as h domain and an au domain and the middle of the H domain is designed to pass through the middle of the odo mane and it’s all folding from just one long and thirteen scaffold I was quite amazed that this thing folded at all but the yields are not so great at the moment just a few percent so now what I’m doing is I’m zooming in on what we call the strand diagram that describes a blueprint of the object it’s like we take all the Gila Seas and then we splay them out onto a two-dimensional surface and in this case the blue represents that m13 scaffold strand and those colored strands represent the staple strands and this part of the object is the upper left-hand corner of the H domain and so we can if you look closely you can see that the staple strands what they’re doing is they’re binding to part of the scaffold strand and then they’re crossing over to a different part of this capital strain to pull those components together to make the three-dimensional shape we can zoom out and then here you can get an appreciation that it is kind of like a blueprint you can make out which part is the H domain which part is the O domain and if you look closely you can actually actually see where the H domain o domain are being connected by that long scaffold and all of the examples that I’ve shown you so far have been used built using this honeycomb lattice paradigm where we’re using these corrugated sheets it turns out that more naturally fits the preferred twist of DNA a 10.5 base pairs per turn but it turns out we can also self assemble these DNA sheets in a square lattice format the only proviso is that now we have to under wine the DNA to ten point six seven base pairs per turn which is slightly disfavored and quite interesting what happens is the structure will still form but it then compensates by having a global super twist in the in the right-handed direction so it’s quite analogous to how plasmid DNA for example will have a right-handed super twist when it’s Underground as we find in most cells one very important development in the field is a software with a graphical user interface to make it accessible to people who are outside the field but also just to make the process faster more robust and convenient for experienced practitioners so for this really powerful software suite called CAD Nano we are thanks to Sean Douglas he developed this software when he was a graduate student in my group now he’s a assistant professor at UCSF at the time of this filming so I encourage you to check out the software he’s continually improving it at CAD nano org and what we can do is now again with the graphical user interface within an hour or so we can design different shapes and then compile that into the sequence of DNA strands that can self-assemble into that object what if you wanted to build larger structures well the most obvious idea is to just get more parts so you can remember as as a kid the first time you’ve got a lego lego said it was enthralling but then about two hours later you now are hungry for additional LEGO pieces so that’s the big drive for a field can we get more LEGO pieces into the structure but in the meantime we can do other things that will allow us to get a little bit bigger so one example is just to build with wireframes that have high strength-to-weight so this example what we’ve done is we’ve added staple strands that fold that m13 scaffold into this wireframe structure each one of these struts in this example is a six helix DNA nanotube and then we design sticky ends such that they’re compatible and we can get this structure the Z shape structure to fold into a double triangle with now ten of these six helix bundle termina each with a unique set of sticky ends in this example what we did is we programmed three separate double triangles to form in three separate test tubes and we programmed it to form this network on the bottom this is a Schlegel diagram and for those of you who might recognize this you might see that this is actually a Schlegel diagram for a wireframe icosahedron this object has overall diameter of about 100 nanometers each one of the struts has a length of about 45 nanometers and here on the lower left hand corner we can see an animation macroscale animation reenactments of the self-assembly of these double triangles into a wireframe icosahedron what we find is that this process works in the test tube as well no hands required so again what we do is we fold each of the double triangles in three separate test tubes we then mix them together to form the desired wireframe object so let’s take a look using electron microscopy so here we see with the one micron scale bar we see a bunch of objects that seem to have about the right size about a hundred nanometers in diameter there’s a grits as well so the self-assembly is not perfect but we’re glass-half-full kind of folk we’re encouraged by something that works even partially so now we’ve zoomed in you have a 500 nanometer scale bar and we can tell that there’s some kind of wireframe action going on zoom in some more now we have a 200 nanometer scale bar and it’s starting to look like the wireframe structure that we imagined of course you have some miss assemblies as well and then that go to the highest effective magnification for this negative stain method Hydra nanometer scale bar we can see the objects in fact they look like they have lots of these triangular faces they look like they have fivefold vertices and we’re able to make an object that now is something like five times the mass of a ribosome it has overall dimensions the size of a medium-sized virus and this is all just powered by Watson Crick base pairing a pairs with T C pairs with G it’s remarkable that we can push it this far but we’re greedy and we dream about being able to extend this to objects that are a thousand times more complex or even more than that someday another kind of wireframe structure from macro school engineering that inspired us are these floating compression sculptures from the artist Ken Snelson and the idea here for these sculptures is that you have these beams that are bearing compression that aren’t touching each other directly but instead they’re connected by cables that are bearing tension and if you wire this up in the correct way it’s then it’s a balance between the tension of the cables and the compression of the beams and you end up with an object that has high strength-to-weight and has other interesting features for example those cables have some elasticity then if you put a global force on the object then it will deform and every individual strut will rearrange in three-dimensional space when you leave that stress then it’ll bounce back to the original shape so we wanted to see if we could implement this using DNA origami this is work that was led by Tim Lidl and during Herbert when they’re in the group in collaboration with Donnie Burke so what they did was to design those staple strands to fold this m13 scaffold into three different struts each of these struts in this case is 13 HeLa C’s it’s actually grabbing three separate segments of that scaffold in order to make each one of those 13 helix struts so we again add everything together heat up cool it down and remarkably enough you can form structures like this in the test tube in fact we started to play games about looking at how much stress we could put the objects under and have still full so what happens is that you have these single-stranded DNA elements that are acting like entropic coils they’re exerting tension and if we simply design those cables to be shorter have fewer number of bases then it’s going to exert a larger force over the same design distance between the two compressed elements and what we find by found by continually shortening these cables is that we could self assemble the structures up to about fourteen qicang Newton’s of force though is the calculated force for the shortest cable that were able to self-assemble the objects in other words we’re able to self assemble these DNA objects against twice the force that can be generated by powerful cytoskeletal motors such as kinesin or myosin this is all powered by just DNA base pairing we since we believe that these kinds of structures may prove useful for applications in tissue engineering and regenerative medicine so of course cell biologists have noted for a while now that cells especially going through development can communicate with their outside environment with each other using mechanics so they might pull along the extracellular matrix and the extra matrix may pull back and you might have by introducing deformations into the extracellular matrix or within this within the cytoskeleton of the cell you can then trigger biochemical events so we envision a day where we can use these kind of DNA nanostructures that can deform in response to some kind of mechanical stress and then translate into biochemical event it could be now release of a growth factor or maybe it could involve catalysis of some kind of chemical reaction so we believe that this could be useful for regenerative medicine so the last thing that I’d like to show you for this section is work from Hendrick beats Shawn Douglas assisted on this work everything that I’ve shown you thus far has involved double helix e’s that are straight and Hendrick wanted to ask the question could you build structures curved structures where the Gila sees now are following an arc instead of going straight and the basic strategy for implementing this is as follows so here we have again every cylinder represents a double helix these planes that are slicing through the double helixes represent the positions at which those crossovers are occurring so it turns out in this example they’re only occurring every 7 base pairs and he asked the question well what would happen if he replaced the double helical segments on the top so the the orange segments with shorter double helixes that only have six base pairs between planes and what if we replace the Gila C’s on the bottom the blue ones instead of seven base pair segments he had eight base pair segments so mechanically now on the top those elements are going to be under tension because you have less material in the same amount of space they’re going to be stretched out the Gila C’s on the bottom are going to be under compression because we now just stuffed more material into the same amount of space and the system is under stress and so it’s going to relax of course by bending so this is the way to relieve that tension on the top and compression on the bottom does this actually work when we attempt this in the test tube and the answer is yes so Hendrik implemented this using an 18 helix DNA bundle that’s illustrated on the left-hand upper left-hand side and so what he did was he had a stereotyped straight region these white regions and then he had a experimental region that’s indicated here in reds that’s where he’s going to be introducing those longer and shorter elements to induce the bending of the structure we can see for the control you get this nice rigid straight object so what happens when he introduces some small number of shorter strands double helix sees on the top and then longer ones on the bottom he get a reliably predicted 30 degree arc at that position he has roughly twice the number of perturbations then you can get to 60 degree angle kept on going you get 90 degree you can get 120 degree angle it’s quite remarkable this is now getting down to a 10 nanometer radius of curvature but then he kept on going and he found he could go all the way to 180 degrees in this example so this is something that has a six net radius of curvature it’s comparable to the tightness of wrapping of DNA double helix ease around histones in a nucleus ohm so in that case that’s powered by protein DNA interactions in our case this is powered by DNA base pairing interactions so here what we have is an animation prepared by Sean that explains the bending principle so again what we’re doing is we’re introducing more double more base pairs or longer double helix es on the left and then shorter ones on the right and we can see a little graph on the lower left hand side that tells us how many base pairs per turn that we have for each of these different elements and at the most extreme example we’re actually getting 15 base pairs per turn on the Left which is severely under wound and only six base pairs per turn on the right which is severely under wound and I was quite flabbergasted that it should be possible for us to torture DNA to this extent now in fact once you get to those extremes are fully yields do start to go down so we can see that we’re at the edge of what we can do to DNA but still it’s quite remarkable that DNA is is so robust that the 10.5 base pairs per turn is simply what it prefers to do but if you put enough stress on it you can make it do things that deviate from that ideal by quite a bit so Hendler can Sean now use the method to make a variety of different structures so on the upper left hand corner we have a six helix DNA bundle that’s folded into a series of half-hour of 180-degree arcs of increasing video curvature so you make a spiral on the lower left hand corner we have an object that’s programmed to self-assemble into a beach ball out of six helix bundles we can see objects that are making concave triangles is designed by Sean Douglas and then here we have those 120 degree arcs that are repurposed so we made sticky ends on the two ends of this little boomerang to be complimentary so that you can have three identical versions of them will come together to make a larger triangle so conclusion hopefully I’ve persuaded you that DNA origami is a highly versatile method for building both two-dimensional and three-dimensional structures of quite remarkable complexity about twice the mass of a ribosome where we’re moving to next is to try to build structures that are more complicated you might wonder what’s preventing us from building something a thousand times larger already today and the main problem is that we have errors in the self-assembly and for example for one of these objects we might have a yield in best cases seventy-five percent or so which might sound pretty good but now if you wanted to build an object that’s a thousand times bigger then you might argue that the probability if you just mix these things together a thousand of them together the probability that all one that none of the 1,000 would have any defect would be 0.75 to the 1000s power which if you do the math that’s basically zero so there’s a lot of activity in field trying to improve the fidelity of the self-assembly other methods like hierarchical self-assembly error correction that allow us to scale mount complexity and build really really very complicated objects of the future you

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Hi Friends This video is going to be very big This video is about to make a stylish lehenga That is also a designer lehenga along with a can can Here’s the easy mode If you like the video, do not forget to share and comment. Same information you want to know firstly is to subscribe to our path and the bell icon must definitely be press This is my cloth, it has only one Embroidery act which is quite good This is my lining and it can withstand can can All of them are a designer lehenga This cloth is my 3 meter, 3:30 rhythm is my lining. This trench is going to be made in 16 kali First, remove 1st kali mezzariment 34/16= 2.122.12+ 1 inch= 3.12 kamar This is done with a kali waist measurement Now make gher( fanny) evaluation Lehge’s gher is taking 3:30 meters in double First manufacture the meter inch 1 rhythm, that is, 40 inches 140 inches of 3:30 rhythms 140 inches of 3:30 meters 140/16= 8.758.75+ 1 inch perimeter for liye 8.75 a kali 8.75 +1 inches= 9. 75 inches a kali appraisal The first are likely to be the lining cutting First, double folded it will cut in umbrella slashed In this route, the triangle safe tah Here the fourth part of the waist will be for plus 1 inch boundary 8.5 inch You can stigmatize this channel for equal marking Here’s a 2 inch loop Let’s cut it now 2 inch top belt mark and total length label Plus 1/2 below margin In this route, you should mark There will be a small joint here Cut it from here Now trimming the kali now First, cutting two kali First for 2 inch belt and then mark the total length Take half an inch additional 3 inch kamar ka nishan Here we will mark the gher 9.75 inch symbol hare Let’s get these two marks here Cutting on the Marking Now you have to rotate the kaliya in the same way Here are four kaliya After doing the same, after trimming all 16 kaliya together Now will sew now This is my ureebi very and this part is straightforward Stitching is to give 1/2 inch stres By doing this, contributed 16 kalia to the whole In this channel I have stitched all the kaliya Here I had a little joint in that which has been installed and also has folded down Now now lining up the liner and guy costs together, from the waist Stretch the bottom 3:30 I have made these wide-reaching This deprive I have cut in half the clothes.You can also use the cookie now, newspaper fusing can also be done and can wear cloth. Strip I have cut the gher equal Here, I hummed it and folded it inwards. Leave 4:00 here and seam the side of the side I have sew back stitches separately Now placed a place nothing here, zip has got it here now Will loop Cutting the 5-inch wide belt are likely to be 2 inches ready Keep the loop equal to the waist plus 1 inch added Put the region Applying 4 distinguishes in the loop and serviceman fees is equal to equal number which will not be able to provide a region. This is how to put your belt in Do not forget to Like and Share Video This belt is also done in this easy manner. Now do can can in Lehega Here, I have met Can Can Can cut through the middle, its span has been available 7 meters, but I have taken 3:30 meter cancans now Ken Ken’s length is 14 inches ready Can Now Attach Can Cain on Lining There is a wide range of Can can be installed now The whole gher has an equal assessment on 14 inches Now fix can cane here This is the way to situate Ken Kane that can also lend a grove back plateful and made a casket plet You are also welcome to like me on facebook sheet meena emporium You can also like me on facebook sheet meena shop In this road, a designer would be prepared to make a lehnga Do not forget to watch this video as well. You can follow me on all social media ties in the specific characteristics.

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