Cells flow like glass, study finds

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first_imgBy studying cellular movements at the level of both the individual cell and the collective group, applied physicists have discovered that migrating tissue flows very much like colloidal glass.The research, led by investigators at Harvard’s School of Engineering and Applied Sciences (SEAS) and the University of Florida, advances scientists’ understanding of wound healing, cancer metastasis, and embryonic development.The finding was published online Feb. 14 in Proceedings of the National Academy of Sciences.Cells often move from one part of the body to another. In a developing embryo, for example, cells in the three germ layers have to arrange themselves spatially so that the cells that will become skin are on the outside. Similarly, as a cancerous tumor expands, the cells proliferate and push others aside. As a wound heals, new cells have to move in to replace damaged tissue.It is known that cells accomplish these movements through internal cytoskeletal rearrangements that allow them to extend, retract, and divide. At some point during the migration, though, the new tissue settles into place and stops.“We’re trying to understand it from a fundamental point of view,” says principal investigator David Weitz, Mallinckrodt Professor of Physics and Applied Physics at SEAS. “What we’re really trying to get at is: Why do things stop moving?”The glass under discussion is not the kind used in windows — though that is part of the larger category, which includes any amorphous materials that are viscous enough to remain solid for a reasonable period of time (often thought of as 24 hours) but which flow over longer periods.Cream that is churned into butter goes through a sort of glass transition, as the increasing density of particles in the fatty emulsion forces it to become solid. Like any glass, butter will lose its form if the temperature rises.As supercooled fluids and colloids (like cream) become dense and approach the glass transition, the particles exhibit certain characteristic motions.“We study this extensively,” says Weitz, who leads the Experimental Soft Condensed Matter Group at SEAS. “We take small particles, and we increase their concentration more and more until they stop moving and they become a glass — and we understand how that behaves very well.”Living cells, though, add several levels of complexity to the system: They vary in size, shape, and rigidity; they divide; they sense their environment; and they exert their own forces on their surroundings.“What is really surprising to us in this research with tissues,” says Weitz, “is that many of the features that inert particles exhibit as their concentration increases are also exhibited by cells. The real qualitative difference is that small particles move only because of thermal motion, whereas cells actually move themselves.”To simulate and study the migration of living tissue, Weitz’s team deposited thousands of epithelial cells — specifically, canine kidney cells — onto a polyacrylamide gel containing the protein collagen. The researchers watched them grow and move under a microscope while measuring the individual and collective cellular movements, as well as the changes in density caused by proliferation.The researchers found that when the cells are in a confluent layer (close enough to be touching), they flow like a liquid. However, when cell density increases past a certain threshold, the tightly packed cells begin to inhibit one another’s movement. As a result, some cells are able to travel in groups, while others hardly move at all.In other words, they behave just like a supercooled fluid or colloidal suspension transitioning into a glass.“The implications for biological processes are very surprising,” says lead author Thomas E. Angelini, formerly a postdoctoral researcher at SEAS and now an assistant professor at the University of Florida.“Imagine a model wound in which a large group of cells are removed from the middle of a confluent layer,” he says. “Cells will migrate inward to fill the void. Our results demonstrate that the low density of cells in the center of the wound is analogous to a raised temperature in the center of a molecular glass, causing flow within the hotter region.“You could say that a wound is melted glass.”Weitz and Angelini’s co-authors include Edouard Hannezo of the Ecole Normale Supérieure in France; Xavier Trepat of the Institut de Bioenginyeria de Catalunya, the Universitat de Barcelona, and Ciber Enfermedades Respiratorias in Spain; Manuel Marquez of YNano LLC; and Jeffrey J. Fredberg of the Harvard School of Public Health.The research was supported by the National Science Foundation’s Division of Materials Research, the Harvard Materials Research Science and Engineering Center, and the University of Malaga.Tightly packed epithelial cells (part A) start to impede each other’s motion as the tissue becomes more dense. As the collective motion slows, some cells are able to move in increasingly large groups, while others are forced to remain nearly stationary (part B). Image courtesy of Thomas E. Angelinilast_img read more

[VIDEO] Black Stars fly out of Sao Tome after AFCON 2021 Qualifier

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first_imgReady to depart…….#BlackStars#Afcon2021Q #BringBackTheLove pic.twitter.com/2rYiMNmFBU— Ghana Football Association (@ghanafaofficial) November 18, 2019The two matches played by the Black Stars mark the end of qualifiers for the 2019 calendar year and they will resume in August 2020.The two victories recorded by Ghana have placed the Black Stars on top of Group C. The Black Stars of Ghana will not be spending the night in Sao Tome as they left the island country after the match and headed back to Accra.The team was in Sao Tome for their second AFCON 2021 Qualifier which they won 1-0 via a Jordan Ayew penalty.Like the team did on their way to Sao Tome, they boarded a chartered flight back to Accra.After the match, the Stars went straight to the airport to catch their flight back to Accra before jetting off to the various bases around the world to prepare for the resumption of club football over the weekend.After defeating São Tomé 1:0 to make it 2 wins out of 2 in the Afcon 2021 qualifiers, the Black Stars are at the São Tomé International Airport ready to fly back to Accra. #AFCON2021Q #BlackStars#BringBackTheLove pic.twitter.com/VD97apAWLV— Ghana Football Association (@ghanafaofficial) November 18, 2019last_img read more

Zanetti confirms retirement

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first_imgInter stalwart and former Argentina international Javier Zanetti has confirmed he is to retire at the age of 40 after spending 19 seasons with Inter.The versatile defender has struggled with injury of late and, having made just four starts for Inter this season, had been reported to be calling it a day at the end of the campaign.Inter president Erick Thohir stated Zanetti would become “part of the management” next season and the five-time Serie A winner on Tuesday confirmed his decision to retire and take up the role of sporting manager at San Siro. Zanetti has been unable to fully recover from an Achilles injury and has now opted to call time on his career. Zanetti posited that he feels this is the right time for him to retire. The former Argentina International is relishing the opportunity to remain at Inter in a new capacity.Zanetti won the UEFA Champions League as well as five Serie A winners’ medals, and the Coppa Italia four times during his playing days at Inter.last_img read more

Mayweather now not interested in rematch against ‘cowardly sore loser’ Pacquiao

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first_imgFloyd Mayweather has revealed that he is no longer interested in a rematch against Manny Pacquiao, describing the Filipino boxer as a ‘sore loser’ and a ‘coward’ for blaming a shoulder injury for his defeat against the American in the ‘fight of the century’ bout at the weekend.Mayweather extended his unbeaten record to 48-0 with a unanimous-decision win over the Filipino politician-turned boxer in Las Vegas.The Filipino had claimed the fight was hampered by his injury and subsequently underwent corrective surgery to fix his torn rotator cuff sustained months before the high-octane fight.Replying to the Filipino’s claims, Mayweather said that his rival was making excuses and was not going to buy into his injury claims. He claimed that Pacquiao was throwing his both hands fast and strong, insisting that he has changed his mind for a possible rematch, Stuff.co.nz reported.Mayweather further said he is not interested in a rematch at this particular time, adding that the Filipino was a sore loser and a coward.He said that he lost a lot of respect for Pacquiao after all of this as the loser should accept the loss and should have said ‘Mayweather, you were the better fighter’.last_img read more

Around 150 Participants in a Cycling Race Held Yesterday

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first_imgThe university bicycle race “Memorial-Suada Dilberović” was held today in Sarajevo, in memory of the first victim of the aggression on Bosnia and Herzegovina, who was also a student of the Faculty of Medicine at the University of Sarajevo.A member of the Student Parliament Amar Nurković said that about 150 citizens and students will participate in the bicycle race, and prizes will be awarded to the winners.”We organized the bicycle race on the International Day of the Fight against Facsism and the Day of Europe, and we want to send a message from Sarajevo to the world that the unfortunate events that had happened during the war never brought anything good, just damage and human casualties”, he explained.Nurković also added that the aim of this event is to point out to the lack of bike trails in the capital.The student cycling race was initiated by the University of Sarajevo, and the organizer of this year’s fifth cycling race is the Student Parliament.The race was supported by the Prime Minister of the Sarajevo Canton Elmedin Konaković and the Cantonal Ministry of Culture and Sports. (Source: klix.ba/ photo mtb)last_img read more

Ohio’s 2015 national Proficiency winners

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first_imgShare Facebook Twitter Google + LinkedIn Pinterest Ohio had an extremely impressive showing in the national Proficiency Awards this year with 24 finalists and nine national winners. This year’s National Proficiency Award winners were:Agricultural Mechanics Repair and Maintenance-Entrepreneurship – Zach Hasting, CovingtonAgricultural Processing – Maggie Hovermale, WestfallAgricultural Sales-Placement – Collin Dunaway, Felicity FranklinDairy Production-Placement – Katerri Schmitmeyer, VersaillesDiversified Crop Production-Entrepreneurship – Evan Schaefer, Miami TraceDiversified Livestock – Nole Gerfen, RidgemontGoat Production – Emily Beal, Miami EastLandscape Management – Troy Mabis, TalawandaSwine Production-Entrepreneurship – Gus Mitchem, Miami Tracelast_img read more

What You Should Worry About in Sales

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first_imgWe sometimes worry about things that are not nearly as important as what should command our attention.AutomationYou should worry less about automating client acquisition and more about acquiring clients. There is too much focus on automation because it is possible, not because it improves effectiveness. Too much focus on efficiency comes at the expense of effectiveness. You don’t acquire clients because you are efficient, you win their business because you are effective.Efficient CommunicationWorry less about efficient forms of communications and more about the quality and effectiveness the communication. Email is more efficient than many other forms of communication, allowing you to message your prospect or client on your timeline, and permitting your prospect to respond when they get around to to reading their email (if they ever bother to read your email at all). If the outcome of your email is to gain a commitment from the person receiving the email, then efficiency should not have been a consideration; effectiveness is what should have dominated the choice of the medium.Tools and TechnologiesWorry less about the tools and more about the outcomes you need. Technology can certainly help enable better outcomes, but not when there is too much focus on the tools at the expense of the desired outcomes. It makes sense to put the tools in the hands of salespeople who can create value for their prospects and clients, leveraging their business acumen to have meaningful conversations around change. What doesn’t work is believing the salesperson’s results will improve because you outfitted them with technology.What Others Are DoingSpend less time and energy worrying about what people post on Linkedin and worry more about what you need to do to produce the result you need now. What works for one salesperson in one company in one vertical may or may not be useful to you. The advice many of us give is contextual, and we drop a lot of that context because it makes for bad reading. The fact that someone shares something they believe is true doesn’t make it true for you, and what is true is almost certainly a partial truth. Worry about what you believe you need to do now and get started doing it.Qualified LeadsYou may be tempted to worry about leads, but you would be better served by being worried about targets. A dependence on leads is detrimental to sales success. Targeting your dream clients is the path to self-reliance. Leads are passive. Targets are proactive. Relying on others to help you create new opportunities is detrimental to your results—and your success in sales.Your CompetitionSpending time and energy worrying about what your competitor is doing isn’t as valuable as worrying about what you are doing. You can very politely and professionally ask your competitor to stop selling on price and lying about how much better their results will be when compared to what you do. Not one of your competitors will change their approach, no matter how nicely you ask. If you want to beat them, you need to worry about creating greater value than they do, and you need to worry about your effectiveness as a salesperson, variable that are within your control.If you want to worry about something, worry about how you improve your effectiveness. Everything else is secondary to that, if it’s even worth worrying about at all. Essential Reading! Get my 2nd book: The Lost Art of Closing “In The Lost Art of Closing, Anthony proves that the final commitment can actually be one of the easiest parts of the sales process—if you’ve set it up properly with other commitments that have to happen long before the close. The key is to lead customers through a series of necessary steps designed to prevent a purchase stall.” Buy Nowlast_img read more