Commuting with Cavafy

first_img Facebook Twitter: @NeosKosmos Instagram Eighty years after his death, C.P. Cavafy has been given a new lease on life – in the streets of Athens. Celebrating its acquisition of the Cavafy archives, the Onassis Cultural Centre has covered buses, trams, suburban trains and metro stations in Athens with lines of Cavafy poetry and stencilled portraits of the famous Alexandrian. Coinciding with the 150th anniversary of the poet’s birth, the event is symbolic of the Onassis Centre’s decision to make the contents of the Cavafy archives available to wider audiences. The initiative “marks our stance on Cavafy’s work and on how we want the archive contents to be made public,” said Afroditi Panagiotakou, the executive director of the Centre. “As they circulate in the city on mass transportation, the verses can prove to the public that doesn’t know his work how familiar he really is, and how well he expresses the spirit of our times.” Source: ekathimerinilast_img read more

Of wrinkles and wires Capillarityinduced skin folding spontaneously forms aligned DNA nanowire

first_img , Nanotechnology Fig. 2. Capillarity-induced skin folding. (A) Optical microscope image of an array of wrinkles and folds around the boundary of a water droplet placed on a wrinkled surface (t = 20 min, ε ≈ −0.03). The blue arrow indicates a water filament. (B) Schematic illustrations of the wrinkle-to-fold transition of the skin due to surface tension forces of water. Representative AFM images and the line profiles are shown below the illustrations. (C) Schematic illustrations and optical microscope images showing the evolution of localized folds with increasing ε (t = 10 min). A water droplet was placed on the surface before compression; the blue arrow and red triangles indicate the formation of a water filament and localized folds, respectively. (D and E) The peak-to-peak distance of wrinkles (LW) and folds (LF) and the length (l) and spacing (s) of the folds as a function of t. (E, Inset) Schematic illustration showing the top view of an array of folds at the boundary. (F) LW and LF as a function of |ε| (t = 3 min). (F, Inset) Line profiles of the folds for |ε| ≈ 0.02, 0.08, and 0.17. (Scale bars: A, 10 μm; B, 5 μm; and C, 50 μm.). Credit: Nagashimaa S, Haa HD, Kima DH, Košmrljb A, Stone HA, Moon M-W (2017) Spontaneous formation of aligned DNA nanowires by capillarity-induced skin folding. Proc Natl Acad Sci USA 114:24 6233-6237. Journal information: Proceedings of the National Academy of Sciences “This phenomenon can be considered a lithography-free method that allows for ready fabrication of arrays of nanomaterials, where their size, length, and periodicity could robustly be tuned,” he continues. “Moreover, not only water but other liquids could be used to carry nanomaterials and to induce the wrinkle-to-fold transition.”Moon describes several examples of potential de novo fabrication and analysis techniques, including nanoscale lithography, nanoimprint, growth by chemical vapor deposition, and chemical reaction. “Our method can potentially be used for the fabrication of 1-dimensional nanowires or nanoarrays for application to DNA analysis with very dilute or small amounts of DNA; DNA templates as new metal or ceramic nanostructures; and DNA treatment devices for healing modified DNA. In addition, one can adopt this technique to handle protein, blood, or nanoparticles at nanoscale.”Košmrlj and Stone tell Phys.org that one area of planned research is focused on nonlinear analysis and modeling for improved quantitative understanding of the capillarity-induced wrinkle-to-fold transition. “Since our system is composed of the mechanical behavior of the fold transition triggered by liquid surface tension, the wrinkle-to-fold transition that we’ve found is associated with large deformations where conventional linear elasticity theory does not apply. While the basic mechanisms can be explained within the linear theory, quantitative comparison with experiments can only be achieved by taking into account geometrical and material nonlinearities. We are therefore performing numerical simulations by coupling liquid surface tension and solid deformation, as well as performing analysis with perturbation series, where nonlinearities of elastic structures can be studied systematically.””I also think that the challenges ahead are to find how to achieve larger areas for DNA pattern formation,” Moon says. “In fact, our latest results—obtained after this PNAS article was accepted—shows some impressive progress for the region with wrinkle-to-fold transition in larger areas, such as the entire area underneath a water droplet. Another area to be studied, Moon continues, concerns the fact that biological morphogenesis of skin–substrate systems are ubiquitous in organisms where water is a major constituent. “We’re trying to find situations where our findings are applicable. Active collaborations with experts in the field would be helpful.” The researchers might also investigate materials other than PDMS. “Yes. other polymers can work if they possess the basic factors to govern the fold transition, these being the thinness of the nano-skin and soft body materials, and surface hydrophilicity to ensure sufficient surface reaction with liquid,” Moon notes. Assistant Professor and lead author So Nagashima, Assistant Professor Andrej Košmrlj, Donald R. Dixon ’69 and Elizabeth W. Dixon Professor Howard A. Stone, and Principal Research Scientist Myoung-Woon Moon discussed the paper they and their co-authors published in Proceedings of the National Academy of Sciences. “I think that the most challenging aspect of devising our method for utilizing a thin skin template that responds to water by dynamically changing its surface morphology was finding the conditions where the wrinkle-to-fold transition occurs,” Moon tells Phys.org. “The critical conditions as a function of the applied strain, initial wrinkle geometries, and thickness of the skin layer determined by oxygen plasma treatment duration were difficult to find.” Moon adds that the observation technique for the dynamic transition was limited to only optical microscopes whose highest optical resolution falls between 100 to 1000 nm in the width of nanowires, this being due to the dynamic transition taking place at the submicron scale.When inducing a template surface wrinkle-to-fold transition by exploiting the capillary forces of water containing DNA molecules, Stone points out, the observation that water changes the wrinkle-to-fold transition is new. “As far as we know, ours is the first study to show this effect, as is demonstrating one use of such folds for the alignment of DNA. Moreover, control of surface tension or resultant capillary forces and the area for fold formation is relatively hard—and by adding DNA molecules to water, it appears that the surface tension is changed, so the fold transition length was shorter.”Template preparation used an oxygen plasma treatment of prestretched polydimethylsiloxane (or PDMS, a polymeric organosilicon compound) substrates for varying durations. “In fact,” Moon explains, “the manipulation of PDMS with prestretching strain is a relatively well-developed method as is the oxygen plasma treatment: both have been discussed in the literature. We can make the samples with various sizes of a few millimeters to a few centimeters, which can be also made on much larger area.” Moon notes that the researchers can also vary polydimethylsiloxane’s mechanical properties—to make it more stretchable, soft or flexible—by changing the ratio of elastomer and cross-linker for PDMS preparation. Fig. 1. Spontaneous formation of aligned DNA nanowires. (A) Schematic illustrations of the spontaneous formation of an array of DNA nanowires by the skin folding induced by water filaments containing DNA molecules. (B) Sequential optical microscope images of a droplet of DNA solution spreading over wrinkles (t = 5 min, ε ≈ −0.03); the wrinkle-to-fold transition occurs at the boundary and propagates with the edge of the droplet. (C) AFM image of an array of DNA nanowires extending from the boundary (t = 2 min, ε ≈ −0.02). The line profiles for each region are shown next to the image. (Scale bars: B, 50 μm and C, 4 μm.). Credit: Nagashimaa S, Haa HD, Kima DH, Košmrljb A, Stone HA, Moon M-W (2017) Spontaneous formation of aligned DNA nanowires by capillarity-induced skin folding. Proc Natl Acad Sci USA 114:24 6233-6237. Citation: Of wrinkles and wires: Capillarity-induced skin folding spontaneously forms aligned DNA nanowire (2017, June 19) retrieved 18 August 2019 from https://phys.org/news/2017-06-wrinkles-wires-capillarity-induced-skin-spontaneously.html Other possible future research interests and additional innovations mentioned by the authors include:- theoretical analysis to elucidate the underlying physics related to the water-induced surface folding- exploit the underlying physics to develop a robust and mass fabrication method for inducing the wrinkle-to-fold transition- find and discuss morphological changes in nature where water is likely a key factor- apply the current study’s results to DNA analysis or DNA drug devices- 2-D/3-D sensors, diagnostic tools, and drug-release systems- templates for fabricating 1-dimensional nanomaterials- methods for local patterning”I believe that this work is beneficial to materials science for nanowire templates, mechanics for fluidic channels, and biology for quantitative analysis of DNA or other biomolecules,” Moon concludes. Explore further , Journal of Biomedicine and Biotechnologycenter_img More information: Spontaneous formation of aligned DNA nanowires by capillarity-induced skin folding, PNAS (2017) 114:24 6233-6237, doi:10.1073/pnas.1700003114Related:1DNA nanowire fabrication, Nanotechnology (2006) 17:R14m https://core.ac.uk/download/pdf/1559975.pdf2DNA-Templated Self-Assembly of Protein Arrays and Highly Conductive Nanowires, Science (2003) 301:5641 1882-1884, doi:10.1126/science.10893893Nanowire-Based Sensors for Biological and Medical Applications, IEEE Transactions on NanoBioscience (2016) 15:3 186-199, doi:10.1109/TNB.2016.25282584DNA-Based Applications in Nanobiotechnology, Journal of Biomedicine and Biotechnology (2010) Article ID 715295, doi:10.1155/2010/7152955Nanowire nanosensors, Materials Today (2005) 8:5, doi:10.1016/S1369-7021(05)00791-1 A key aspect of the study was confirming that the new method reliably manipulates DNA nanowire size, geometry, and alignment. “By adjusting the conditions for stretching strain, plasma treatment duration, and post-compression of the stretched PDMS, DNA nanowires can be a half cylinder, a perfect cylinder, or undulated wire shape,” Moon tells Phys.org. “By changing the wrinkle geometries such as the amplitude—which is governed by the strain—one can control the distance between wires in the fold channel.” Wider distances between wires, he continues, can be accomplished by compressing the PDMS less, while compressing the substrate more yields smaller distances.To address these challenges, the scientists discovered a transformation resulting from capillary forces that act at the edge of a water droplet that can, with only 1% compression, transform wrinkles into folds, which in the absence of a liquid drop form only at very high (~30%) compression. In addition, Moon adds, smaller substances such as biomolecules or nanoparticles can follow the water channel to form aligned 1-dimensional nanostructures. “Smaller is better. Less is more. We’ve found that the wrinkle-to-fold transition takes place more easily when the following factors become smaller: compression level, skin thickness, droplet volume, size of the sample surface, and static contact angles of droplets.”Based on their findings, the authors stated that their approach could lead to new ways of fabricating functional materials. “Our key finding is that one can change wrinkles into localized folds by simply exploiting the capillary forces of water on wrinkled surfaces under very small strain of about 1% in compression,” Nagashima tells Phys.org. “Recent studies reported in the literature have demonstrated that such wrinkle-to-fold transitions can help develop systems that dynamically change their properties according to the surface morphology. However, inducing the transition in the absence of water is difficult to achieve in practice because, in general, large compression needs to be applied to the skin-substrate system, which hinders wider applications. Our study reveals that even 1% of compression, which is the critical level for creating wrinkles in our case, is large enough to trigger the transition to folds locally when water is present.” Nagashima notes that while the compression level required to induce the transition might differ according to the skin-film system used, only a small compression level would be necessary in combination with water. Observation of the phase transition of liquid crystal defects for the first time Fig. 3. Tunable DNA nanowires. (A) Bright- and dark-field optical microscope images of DNA nanowires created by the capillarity-induced wrinkle-to-fold transition. After evaporation of the droplet, the strain was adjusted to see the structure inside the folds. (B) Confocal microscope images of an array of DNA nanowires extending from the boundary to the locations indicated by the yellow triangles. (C) AFM images of DNA nanowires obtained using wrinkles prepared with various ε (t = 10 min). After the folds were formed, the strain was adjusted to ε ≈ 0.00. The line profiles of the nanowires indicated by the green dotted lines are shown in the images. (D) Height of the nanowires as a function of t (ε ≈ −0.03). (E) Changes in shape of a DNA nanowire from straight to wrinkled with an increase in tensile strain. (F) The wavelength (black symbols) and amplitude (orange symbols) of the wrinkled DNA nanowires as a function of applied tensile strain. (G and H) The line profiles of the DNA nanowire and the skin surface before and after application of the tensile strain (i.e., ε ≈ −0.02 and 0.05, respectively). The color of the profiles corresponds to that of the dotted lines indicated in the AFM images shown in E. (Scale bars: A and B, 10 μm; C, 2 μm; and E, 1 μm.). Credit: Nagashimaa S, Haa HD, Kima DH, Košmrljb A, Stone HA, Moon M-W (2017) Spontaneous formation of aligned DNA nanowires by capillarity-induced skin folding. Proc Natl Acad Sci USA 114:24 6233-6237. , Science (Phys.org)—Nanowires fashioned from DNA (deoxyribonucleic acid)—one of several type of molecular nanowires incorporating repeating molecular units—are exactly that: Geometrically wire-like DNA-based nanostructures defined variously as having a 1~10 nm (10−9 m) diameter or a length-to-diameter ratio >1000. While nanowires can be made from several organic and inorganic materials, DNA nanowires have been shown to provide a range of valuable applications in programmed self-assembly1,2 of functional materials—including metallic and semiconductor nanowires for use in electronic devices—as well as biological, medical, and genetic analysis applications3,4,5. That being said, DNA nanowire adoption has been limited due to historical limitations in the ability to control their structural parameters—specifically, size, geometry and alignment. Recently, however, scientists at Korea Institute of Science and Technology and Princeton University leveraged the capillary forces of water containing DNA molecules to demonstrate size-controllable straight or undulated aligned DNA nanowires that were spontaneously formed by water entering wrinkled channels of a compressed thin skin on a soft substrate, which subsequently induced a wrinkle-to-fold transition. © 2017 Phys.org This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more

Teenagers less reckless when elderly around

first_imgHowever, a new study suggests that being in a group that includes just one slightly older adult might decrease the teenagers’ propensity to engage in risky behaviour. “Decision making in groups of adolescents and young adults is more prudent when a somewhat older adult is present,” explained Laurence Steinberg, psychological scientist at Temple University in Pennsylvania, US.The study was designed to shed light on the group performance in the context of army combat teams where many soldiers in the front lines are in their late teenage or early 20s. However, the researchers also maintained that the findings are relevant across various settings, including restaurants and retail stores, which employ a relatively high proportion of adolescents.The study, published in Psychological Science, provides guidance to organisations that should decide on the age mix of their work teams, the researchers revealed. Also Read – ‘Playing Jojo was emotionally exhausting’Some of the participants, all 18-20-year-old men, were randomly assigned to complete the experiment alone, while others completed the task in a group of three same-aged peers or two same-aged peers and one slightly older male. The participants then completed a computer-based driving game, in which one group member was tasked with driving a car along a track as quickly as possible while the others watched.At each intersection in the game, the “driver” had to decide whether to stop for a yellow light, which would incur a time penalty, or to continue driving. If the driver ran through the light, he risked hitting another vehicle, which would incur an even greater time penalty. The drivers were offered a monetary incentive for completing the course quickly, and the observers received bonuses based on the driver’s performance. Also Read – Leslie doing new comedy special with NetflixThe researchers measured drivers’ risk taking as the proportion of intersections at which they did not brake for the yellow light. They also measured participants’ preference for relatively small immediate rewards versus larger delayed rewards.The results revealed that drivers who were observed by peers took significantly more risks and showed a stronger preference for immediate rewards than those who completed the task in a group that included a slightly older graduate student.last_img read more

4 Ways Entrepreneurs Can Accelerate Online Business Growth This Quarter

first_imgMarch 24, 2017 The internet is growing at an insanely fast rate, and every future-thinking entrepreneur should rightly invest in making sure their brands are maximizing the internet to its fullest. Nearly all aspects of business are being aggressively pushed online. Filing systems have gone online. Offline advertising, or traditional advertising as we know it, has been overshadowed by online advertising. As far as traditional business processes go, you name it, and chances are, it’s now online.Related: 10 Fundamental Truths That Will Change Your LifeThis all points to the positive way the internet has changed how we do business. If the internet is changing things, how would you tune your business to rightly position yourself for more growth and better widespread promotion? Here are a few strategies to help you on your way.1. Plan for specific growth.Growth isn’t guess work. Every growth goal must be deliberately planned and pinned down before it becomes achieveable. As an entrepreneur, you need to decide which aspect of your business you need growth in.Narrow down your focus to just an armful of areas. Ask yourself which areas of your business need a thorough makeover in order to bring in more leads? Which areas of your business need to be advertised more? What areas are bringing in the more leads? You cannot answer all these if you don’t monitor your numbers. Every serious-minded entrepreneur knows their numbers. And every entrepreneur should be able to use that data to see loopholes. Growth loopholes, however, are sometimes not easily visible.The best way to know your business growth and numbers throughly is to study your business. Go through each of your online business verticals and jot down how much growth they added in the previous quarters. If you do it well, you’ll have in-depth information about your businesses, ranging from which areas are bringing in the most leads to the areas that should be discontinued. From your final findings, I believe you can plot out a well-defined strategy for promoting your business online.2. Experiment and utilize the right advertisement method.Online promotion won’t work effectively if you don’t understand advertising. Almost all content online is created exclusively for marketing purposes. You would have to do some exploring to know which advertising methods best fit your business. Not every business model will flow with every advertising method. The advertising strategy I used for my freelancing startup wasn’t the same for my cosmetic startup. Niches affect strategies.This is where experimentation is highly needed. When I first started on my journey to make money online, I was skeptical about trying out new stuff. But I soon realized that the only way to reach more customers was to keep on experimenting until I found the winners.It’s from experimentating that I found out that hidden advertisement is hyper-effective for niche product launchings; that Mulpix gives me better insight to Instagram advertising and better use of hash tags than others I have seen; and that having the right personas in business will help you narrow down and get targeted customers.Join the trend and experiment on advertising. Don’t just stop there. Go the extra mile, understand how advertising works, and find out what type of advertising will work best for your type of business. The more you experiment with online advertising, the better understanding you will have about which type of advertising will work for your business and which ones won’t. And the better you grasp this topic, the more promoted your brand will become online.Related: Why Every Marketing Channel Won’t Work For Your Business3. Leverage growth automation.The best growth techniques I know — and sadly I had to learn the hard way — is to automate your online business growth. As a freelancer, I keep coming across companies who are seeking to outsource more work in order to focus on the essentials. To them, it’s better to spend money giving other people time-wasting tasks to manage than to equally focus on the important and time-wasting tasks, and lose out on potential income.According to statistics, businesses are rapidly outsourcing more jobs. Do the same. Automate aspects of your online business that you know next to nothing about. Find ways to make sure you’re only engaged with tasks you can confidently handle and are your areas of strength.Business thrive when there is less noise. Fuzzle out the non-essentials. Look for virtual assistants to help with tasks you can’t handle.There are so many verticals to automate. The more you automate your online business promotion, the more time you have to focus on the company’s growth and getting more clients on board.4. Engage your potential audience.I strongly believe that every business should have a blog (or a vlog). Developing insightful, original and relevant content online positions you as a thought leader within your industry and makes your readers perceive you as a trustworthy voice.Related: #8 Strategies to Create Content Your Audience Will TrustWhen trust enters the scene, you automatically begin to get leads from the people who read your business blog. Without mincing words, Hubspot gets almost all their major leads from their business blog, and they have been able to grow their email list to a gigantic 300,000 vibrant marketers. Now, that’s a lot of potential clients right there.All this happened as a result of providing a solution — which the Hubspot blog was readily doing. When your business starts a blog and focuses on answering every issue a potential visitor will have, you’ve instantly won a customer. 5 min read Opinions expressed by Entrepreneur contributors are their own. Free Webinar | Sept 5: Tips and Tools for Making Progress Toward Important Goals Attend this free webinar and learn how you can maximize efficiency while getting the most critical things done right. Register Now »last_img read more