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Green alternative for light-emitting materials in displays uses plant waste and amino acids

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Green alternative for light-emitting materials in displays uses plant waste and amino acids


When excited by UV-light showing the fluorescence effect from ESPT. Credit: Dr Ho-Yin Tse, Center for Green Chemistry and Green Engineering, Yale University

Scientists have devised a way to create a green alternative to the light-emitting materials often used in TV, smartphones and other display technologies.

The research, led by a team at the Center for Green Chemistry and Green Engineering at Yale University in the US and involving Nottingham Trent University, aimed to address the challenge of “photoluminescent” solid-state materials, which often rely on non-renewable resources and toxic metals.

These materials are also often made in multi-step processes that produce a lot of chemical waste which can be hazardous.

The study is published in the journal Chem.

Photoluminescent solid-state materials work by absorbing UV light and re-emitting it as , providing an ability to glow which makes them ideal for a range of applications such as display technologies, lighting, sensors, security inks, biomedical imaging through to glow-in-the-dark toys.

The challenge for researchers has been to develop these materials from sustainable sources that are environmentally-friendly and in a way that is less wasteful and less hazardous.

As part of the study, the team took lignin—a by-product of the wood pulping and and a natural substance found between and in the cell walls of plants and trees—and combined it with histidine, a simple amino acid, finding they could produce a range of that fluoresce under UV light.

  • Scientists develop green alternative for light-emitting materials used in display technologies
    Graphical abstract. Credit: Chem (2025). DOI: 10.1016/j.chempr.2025.102781. Chem (2025). DOI: 10.1016/j.chempr.2025.102781
  • Scientists develop green alternative for light-emitting materials used in display technologies
    Viewed under ambient light. Credit: Dr Ho-Yin Tse, Center for Green Chemistry and Green Engineering, Yale University

In addition to easily tunable photoluminescent material properties, the preparation of the materials only uses green solvents in the form of water and acetone.

The fluorescence, or lighting, effect relies on specific parts of the lignin—”phenolic groups”—which become energized when they absorb the light.

In this energized state, they release protons to the histidine in the solid structure, a process known as “excited state proton transfer” (ESPT).

As the lignin relaxes back to its normal state, it releases light which can shine at room temperature. In some cases, the materials continued to glow very briefly even after the UV light was turned off.

“The concept of ESPT isn’t new, it is well known in pure phenolic molecules,” said first author Dr. Ho-Yin Tse, a researcher from the Center for Green Chemistry and Green Engineering at Yale University.

“But what is interesting is that lignin’s natural phenolic structures—present throughout the macromolecule—can inherently support this kind of photoacid behavior and this effect has rarely been examined in this context.”

“This is an excellent example of green and ,” said study co-author Dr. Darren Lee, a researcher in sustainable chemistry in Nottingham Trent University’s School of Science and Technology.

He said, “Photoluminescent materials are vital for a range of everyday and smart technologies, but most rely on toxic metals and non-renewable resources.

“In this study we not only simplified the synthesis of these materials but also utilized abundant waste streams to produce tunable materials in a safer way.”

“Computational modeling revealed how molecular interactions between and histidine enable this unique light-driven proton transfer,” said Dr. Chi-Shun Yeung, who led the at The University of Hong Kong.

“These mechanistic insights explain how biopolymers can achieve efficient light emission without relying on metals.”

More information:
Ho-Yin Tse et al, Renewably sourced amino-acid- and lignin-based solid-state emitters, Chem (2025). DOI: 10.1016/j.chempr.2025.102781

Journal information:
Chem


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Green alternative for light-emitting materials in displays uses plant waste and amino acids (2025, November 9)
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In Cryptoland, Memecoin Fever Gives Way to a Stablecoin Boom

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In Cryptoland, Memecoin Fever Gives Way to a Stablecoin Boom


When US president Donald Trump launched his own meme cryptocurrency on January 17, days before his return to the White House, I was halfway up a Swiss alp, attending a crypto conference in the town of St. Moritz.

Memecoins, which typically have no purpose beyond financial speculation, were having a moment. The previous year, millions of new memecoins had flooded the market; a few, like Fartcoin, had rocketed to billion-dollar valuations. Pump.Fun, a platform for launching and trading memecoins, had become one of the fastest-growing crypto launchpad businesses ever. Now, the soon-to-be president was getting in on the act.

Over lunch on the second day of the conference, beneath the ornate stucco ceiling and golden chandeliers of the venue’s dining hall, I located a table designated for a conversation about memecoins. Whereas other tables were half full, the memecoin workshop was oversubscribed; latecomers pulled up chairs to create two full rows.

The discussion was led by Nagendra Bharatula, founder of investment firm G-20 Group. Bharatula had recently coauthored a paper arguing that memecoins, despite their juvenile spirit, had a place in professional investors’ portfolios. In the six months prior, a basket of 25 “bluechip memecoins”—an oxymoron if ever there was one—had outperformed bitcoin by 150 percent, he pointed out. Some of the attendees murmured their approval.

Since then, the shine has come off the memecoin market. The paper value of Trump’s coin, which climbed to a peak of $14 billion two days after its launch, has cratered to roughly $1 billion. Hundreds of thousands of small investors lost their shirts. Pump.Fun’s daily revenue, a proxy for the overall appetite for memecoin trading, is barely more than a tenth of what it was in January. The memecoin gold rush has spawned a raft of litigation.

Next up: the stablecoin. If memecoins are symbolic of reckless abandon and unflinching profiteering in cryptoland, stablecoins are a symbol of the industry’s search for purpose and respectability. Designed to hold a steady $1 valuation, stablecoins are pitched by proponents as a faster and cheaper way to make everyday payments and international money transfers.

In a year in which the US has declared itself open for crypto business, where previously crypto firms feared regulatory backlash under the Biden administration, stablecoins have supplanted memecoins as the coin à la mode—and punctured the mainstream.

Though stablecoins have been around since 2014, they have predominantly been used by crypto traders as a safe harbor during bouts of market volatility, not by regular people. The concept has also faced resistance from regulators skeptical of a new form of money; Diem, a stablecoin venture incubated at Meta, famously shuttered in 2022 in the face of broad-based opposition.



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Best HelloFresh Coupons and Promo Codes for December 2025

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Best HelloFresh Coupons and Promo Codes for December 2025


Leveraging meal kit coupons is the extreme couponing of our times—a capitalism hack-a-thon right up there with trial yoga classes and attempting to cancel your Adobe subscription. Meal kits like HelloFresh have always been a better deal than they get credit for, even at full price: It’s actually hard to recreate meal kit meals for less than you can get the recipes delivered to your home. But it’s especially worth it when you can find a HelloFresh coupon, promo code, or discount at more than half off.

I’ll admit I wasn’t that sold on HelloFresh when I first tried it most of a decade ago. It was useful, it got me out of my staid routines, but I wasn’t impressed with the selection. It felt a little basic. But lately? Honestly, it’s kinda cosmopolitan these days, after expanding to a dozen countries and absorbing the supply networks from multiple other meal plans. When I last tested the HelloFresh meal kit (7/10, WIRED Recommends), I was surprised to find myself cooking credible home renditions of ramen, ponzu-plum beef stir fry, and Southwest-accented pork roasts. And when I’m able to pick up a HelloFresh discount code, it’s generally less than I’d spend on groceries anyway. So it’s a good moment to try out a lifestyle where the food comes in the mail.

Get 50% Off and up to 10 Free Meals as a New HelloFresh Customer

Right now, new and returning customers can take advantage of a HelloFresh discount code offering 50% off your first meal kit box plus a free item each week. Enter your email as part of the signup process, and you’ll be auto-subscribed to an email with even more offers for both new and existing customers. Plus, new customers can get up to 55% off and extra free breakfasts, desserts, and other items with other secret discounts.

HelloFresh Student and Discount: 55% Off, Free Shipping, Plus Extra 15% Off Education Discounts Available via UNiDAYS

HelloFresh meal kits are pretty amenable to dorm life when ordering the ready-to-eat meals—or just saving time during grad school instead of ordering pizza, by letting the Internet do your shopping and meal planning. But student budgets tend to be tight, of course. And so there are steeply discounted HelloFresh coupon codes specifically for students. Follow the link here for a HelloFresh education promo code offering 55% off your first box, free shipping, and a continuing discount of 15% off for the first year.

Discounts also apply to teachers who’ve never tried HelloFresh. Educators and school employees can get up to 12 free meals spread out across 3 boxes, plus free shipping. Click here for the HelloFresh promo code, or go here for more information about educator discounts.

Note that the student and educator discounts don’t combine with any other HelloFresh discounts or promotions.

Special Hero Discount for Military, Veterans, and Healthcare Workers

Military discounts are a long tradition in America. HelloFresh also offers hero discount programs for first responders, health professionals, and military personnel. Heroes also get excellent discounts that include 55% off the first order, free shipping, and 15% off for the first year of HelloFresh delivery boxes.

This program is open to nurses, hospital employees, EMTs, active military, veterans, and first responders. First responders include law enforcement, 911 dispatch, and firefighters. Click here to see if you’re eligible, or follow this link for more information about HelloFresh hero discounts.

Note that the hero discounts don’t combine with any other HelloFresh promo codes.

Give $40, Get $10 With the HelloFresh Referral Program

Already a HelloFresh subscriber? You’re still eligible for discounts if you pass along subscription information to your friends. Here’s how: Send your friends a $40 discount for their own affordable meal kits. Once they sign up using your HelloFresh referral code, you’ll also get a $10 credit on your next delivery.

These discounts stack. So if you sign up multiple friends with your referral code, you get multiple $10 discounts. Check out the HelloFresh meal kit referral program here.

Take Advantage of HelloFresh Come Back Offers

Some of these discounts are only available to new HelloFresh customers. But there’s a hack to getting discounts anyway. After you pause or cancel your subscription, check your inbox after the next few days or weeks. Often, you’ll get HelloFresh coupon codes for discounts.

Typical HelloFresh “come-back” offers after a canceled subscription include: $100 to $180 off (spread out over several meal boxes), free shipping on the first box (after re-subscribing), free items such as dessert, breakfast, or an extra protein per meal, or a free meal box is offered after a break. Typical retention offers, for when customers try to cancel, include: 40% off the next box, if you decide not to cancel, or 25% off the next two meal kits. None of this is failsafe, of course, offers vary for each customer. But as with magazine subscriptions, sometimes canceling, or trying to cancel, will lead to a good discount offer from a company eager to keep your business.

When to Save the Most on HelloFresh Subscriptions

HelloFresh almost always has some sort of deal going, whether to bring in new customers with an especially choice HelloFresh coupon, or bring back previous customers with HelloFresh discount codes and retention offers. But summer tends to be one of the times they offer the steepest discounts, including 10 free meals across several boxes, complimentary appetizers, free ready-made items, or free shipping on select boxes.

The other big times for HelloFresh coupon codes are around Black Friday and the end of the year. HelloFresh often launches limited-edition holiday meal boxes and themed meal kits, not to mention discounts for returning customers looking to cook more at home as part of New Year’s resolutions.



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The Ricoh GR IV, the Cult Favorite Pocket Camera, Just Got Way Better

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The Ricoh GR IV, the Cult Favorite Pocket Camera, Just Got Way Better


When I reviewed the GR III, I wrote about how much I liked snap focus mode, which allows you to set a predetermined focus distance regardless of the aperture. I set up my GR III to use autofocus when I half-pressed the shutter and snap when I quickly pressed, so that snap focus fired off the shot at my predetermined focus distance (usually 1.5 meters).

All that remains, but there is also now a dedicated letter, Sn, on the mode dial that sets the camera in Snap Focus mode, which allows you to dial in not only the distance you want focus at, but also the aperture you want to lock in. You can control the depth of field as well. I rather enjoyed this new mode and found myself shooting with it quite a bit.

Should You Get One?

The GR IV debuted at $1,497, which is significantly more than the GR III’s $999 price at launch. Is it worth the extra money? If you have a GR III and are frustrated by the autofocus, I think you will like the upgrade. It’s significant and, if you have the money, well worth it.

If you have any desire to use your pocket camera for video, this is not the one for you. See our guides to pocket cameras and the best travel cameras for some better, hybrid photo- and video-capable cameras. If you want an APS-C sensor that legitimately fits in your pocket, offers amazing one-handed control, and produces excellent images, the the Ricoh GR IV is for you.

Personally, I am holding out for the GR IVx, which will hopefully, like the GR IIIx, be the same camera with a 40mm-equivalent lens. At the time of writing, Ricoh would not comment on whether there will be a GR IVx.



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