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Warmer temperatures are finally upon us here on the East Coast, prompting many of us to get outside into the sunlight and play. To Bruce Parkinson and colleagues at the University of Wyoming, the sun is more than just a welcome sight after a long winter. It could someday provide a real, sustainable alternative to fossil fuels.

 

The finite supplies of fossil fuels, such as coal and gas, are being depleted. And burning them produces the main greenhouse gas carbon dioxide. Alternative ways to generate energy haven’t really caught on yet, though. They can be costly, and in their current forms, they can’t make enough energy to replace even a fraction of the fossil fuels. Many researchers are working on improving solar panels, but even though their efficiencies have improved and their costs have decreased, they can’t produce power when the sun goes down.

 

Enter Parkinson’s team. They and others are placing their bets on a different way of harvesting and storing energy from the sun. They are working on devices that “split” water (H2O) to get hydrogen (H2) and oxygen (O2). The hydrogen would be used as fuel, which can be stored and used at night when it’s dark, as well as for powering cars and trucks. To make the dream a reality, the materials in the device must be efficient, inexpensive, earth-abundant and stable for years. But what materials would work?

 

Parkinson had a thought — a metal oxide semiconductor would fit the bill as a photocatalyst in such a device, especially if the semiconductor were made of a few different metals. But with about 60 metals in the periodic table, the number of combinations he’d have to test was mind-boggling.

 

After his grad student Mike Woodhouse put together an initial ink-jet printer-based protocol to produce and analyze various metal combinations, Parkinson realized that he had a lot of work ahead of him. He remembers thinking that he’d either have to start a company, hire a bunch of engineers to automate the process or outsource the problem. Because the idea seemed simple, outsourcing seemed like the best option.

 

And that’s how the SHArK (Solar Hydrogen Activity Research Kit) project started in 2006. The kits include materials, such as an apparatus based on a Lego Mindstorm® kit, an electrochemical cell, a green laser pointer, an electronics box and fluorine-doped tin oxide plates. The students use the kits to prepare metal oxide films and test them for water-splitting activity.

 

“We started with undergrads, but enthusiastic high school teachers have taken it to high schools for AP Chemistry classes and science projects,” says Parkinson. He and colleagues have now sent more than 70 kits to high school and undergraduate students around the world.

 

In a recent issue of ACS Applied Materials & Interfaces, Parkinson’s team reports that an undergrad named Thanh D. Do, then at Gonzaga University, happened upon a potential winning combination — a semiconducting p-type oxide containing iron, aluminum and chromium. Do is also a co-author on the paper. John Rowley, a postdoc in the Parkinson lab, using more sophisticated research tools, followed up on his discovery and found that it has many promising properties, such as a high photovoltage. Parkinson says his team and other researchers will continue to improve the material to enhance the photocurrent response.

 

The SHArK project was initially funded by the Dreyfus Foundation and is now funded by the National Science Foundation as part of the “Powering the Planet” Center for Chemical Innovation.


 

What do you think of the project? Would you have volunteered to help when you were a student? Are you interested in helping?


 

“Combinatorial Discovery though a Distributed Outreach Program: Investigation of the Photoelectrolysis Activity of p-Type Fe, Cr, Al Oxides” [Free Editors' Choice link]


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Credit: Bruce Parkinson

 

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Avocados are great with a little salad dressing or as the yummiest ingredient in guacamole. But when you get to the half of the fruit with that big brown seed or pit in it, the fun stops abruptly. Using a knife doesn’t work well, and forget about a fork. Luckily the third key utensil is the magic charm: A nice large soup spoon is ideal for scooping out the seed and the fruit.

Unless you plan to grow your own avocado plant, however, you will throw that seed in the trash. But not so fast!

A recent review article in ACS’ Journal of Agricultural and Food Chemistry says that the seeds and other inedible parts of certain tropical fruits in particular may well contain ingredients for a new, natural weight-loss product. We’re talking about the flower, leaf and peel, as well as the seeds.

After reviewing more than 80 studies done over a decade, Dawei Zhang and colleagues have concluded that these apparently worthless waste products actually contain high amounts of phytochemicals that could help with losing weight.
Phytochemicals
are non-nutritive plant chemicals that can help protect people from diseases. Among these are polyphenols, which are healthful antioxidants.

As yet, there is no clear evidence on exactly how these phytochemicals work to reduce weight, Zhang says. Researchers haven’t isolated the bioactive compounds or discovered if there is a combination of compounds in the fruits that work to reduce weight. But the point is that the fruit waste does appear to be effective in keeping weight down in lab tests, thus helping prevent development of diabetes, for example.


Besides having great potential as an anti-obesity agent, the study team says the fruit waste has a major advantage over weight-loss drugs: It won’t produce side effects as some synthetic meds do. So what are some of these magical inedibles? They include seeds from nuts and corn in addition to avocados; tangerine, mango and prickly pear peels; pomegranate flowers, and mango, guava, papaya and olive leaves.


While studies document how effective these waste fat-fighters can be, no one has described how to extract and process these compounds from foods. “We need to find the right places and equipment to store these fruit wastes to prevent them from decaying,” said Zhang. “We also need to develop large-scale extraction techniques to take up only the parts that we need.” Also important, he said, is to grow large quantities of crops that contain high amounts of the valuable anti-obesity compounds.

 

“The Hidden Potential of Tropical Fruit Waste Components As Useful Source of Remedy for Obesity”

Click here for the abstract.

*Journalists can request a PDF of the journal article by emailing newsroom@acs.org.

 

 

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Credit:iStock/Thinkstock

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Going under the knife for surgery is a scary enough prospect by itself. But throw in the risk of contracting a bacterial infection, and even a routine procedure can become a nightmare.

 

Now, keep in mind that surgical infections only affect fewer than 3 percent of surgery patients nationwide every year and can often be treated effectively. But when infections grow severe, some patients are left fighting for their lives over something that should not have happened in the first place.


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To spur a faster recovery for patients in such cases and those with other severe bacterial infections, scientists are figuring out for the first time how to create a picture of where the harmful bugs are in the body.

 

Doctors can take pictures of broken bones, some tumors, even brain activity. But when it comes to an invasion of bacteria, Anton Bunschoten, Ph.D., says currently approved imaging options are limited to looking for inflammation. Though a body’s local flare-ups can be a result of a bacterial infection, it’s not the sole possible cause — and discerning the source quickly can save lives.

 

If a patient has a hip replacement, for example, and feels pain and other symptoms after surgery, a minor inflammatory response would require a small intervention, says Bunschoten who’s with the radiology department at Leiden University Medical Center in the Netherlands.

 

“On the other side, when it’s a bacterial infection, the whole prosthetic has to be removed and a serious antibiotic treatment has to follow,” he explains. “So it’s really important to know if the prosthetic is inflamed due to a bacterial infection or another kind of inflammatory response.”

 

To take stock of where bacterial imaging research is, Bunschoten’s team looked at the various parallel studies going on and assessed how far along each has come. He reported his findings in the ACS journal Bioconjugate Chemistry.

 

In his review paper, Bunschoten describes several agents researchers are pursuing for imaging infections: antibiotics, carbohydrates, viruses, enzyme-activated tracers and proteins. He says one set stands out above the rest: antimicrobial peptides, or AMPs. These amino acid chains form a part of the native immune system in all kinds of organisms. They work by sticking to bacteria and busting open their outer walls.

 

Some researchers are taking advantage of this bacteria-seeking behavior and attaching radioactive and fluorescent labels to AMPs to see if the peptides can be used for imaging. They’ve already had some success with one particular kind, called UBI for short. Researchers have even tested UBIs in patients in bone, soft tissue and for prosthetic and diabetic foot infections and in cases of fever of unknown origin.

 

Because some of the labels for imaging are radioactive, the risks of exposing patients have to be weighed against benefits. So this type of technique would not be used to confirm a run-of-the-mill ear infection, for example. But for serious infections that occur post-surgery or cause life-threatening diseases like tuberculosis, this kind of imaging could help transform global healthcare.

 

UBIs are not quite ready for prime time, but because they’ve already been tested in patients, they could be on track for practical use within five years, Bunschoten estimates.

 

He acknowledges funding from The Netherlands Organisation for Scientific Research.

 

“Development and Prospects of Dedicated Tracers for the Molecular Imaging of Bacterial Infections”

 

Click here for the abstract.

 

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By any account, the Deepwater Horizon explosion and oil spill in the Gulf of Mexico in April 2010 was a disastrous event. Cleaning up required an infusion of cash to the tune of billions of dollars within a few months.

 

Now consider the “dead zone” phenomenon in the same body of water. It’s a disaster in its own right, but a far more subtle one that doesn’t involve fire, smoke, oil slicked water – nor unfortunately, billions of dollars for remediation.

 

And that’s a problem that weaves together clashing interests across multiple states and the fisheries down south.

 

During fall and spring, farmers apply nitrogen-based fertilizers to their crops. The excess nitrates pour invisibly into the Mississippi River and spill into the gulf. It’s a feast for algae, which thrive on the nitrogen compounds. But the decomposition of the massive algal bloom depletes oxygen in the water.


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Animals that can’t escape the area die. Fish swim away, hurting the seafood industry. The annual event generates a few media stories and then fades away until the next year.

 

This is not a new phenomenon. The National Oceanic and Atmospheric Administration has been mapping the zone since 1985. State and federal agencies have implemented programs over the years to stem the flow of nutrients.

 

What is surprising is that years of such efforts have not paid off. In 2013, the dead zone was the size of Connecticut, which was smaller than experts had predicted but three times larger than the goal set by an Environmental Protection Agency task force in 2001.

                                                      

Mark David, who has been studying agriculture and water quality in Illinois for two decades, wanted to know why.

 

After evaluating the situation, he found that while small programs have some effect, larger forces overwhelm local benefits. His report appears in the ACS journal Environmental Science & Technology.

 

“In the big scale of things, we’ve done very little,” says David. “In some ways, we’re going in the opposite direction with more corn and more drainage.”

 

When farmers first settled in the Midwest, David explains, though the land was extremely fertile, it was also extremely wet. Plows would get stuck in soggy ground. To make the land more crop friendly, they buried one-foot long clay pipes, or tiles, to redirect the excess water from the fields. The effect was dramatic. The land yielded bountiful harvests on some of the best agricultural soil in the world.

 

But along with the excess water, the tile system flushes out nitrates from fertilizer. And the drain is the mighty Mississippi.

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With demand high for biofuel, corn pays very well these days, David says. Now, tens of millions of acres from southern Minnesota to Ohio are on tile drainage, contributing a constant flow of nitrates each spring into the river, he adds.

 

“We want clean water, but we’re doing everything possible to maximize corn and soybean production,” David says. “And corn and soybean production on tile-drained land is about as leaky a system as you can have.”

 

To compound the problem, David says, farmers have few incentives to mitigate run-off. Planting specific winter crops, called cover crops, that improve soil quality and retain nitrogen would cost farmers an additional $30 to $40 per acre. Woodchip bioreactors — enclosed beds of woodchips — placed at the end of field drainage pipes remove nitrates but cost around $8,000 each.

 

“I think we know how to reduce nitrates,” David says. “It involves working more closely with farmers. But many practices that reduce nutrients don’t increase profitability. Somewhere we need to figure out how we’re going to pay for the practices that improve water quality but don’t boost yields.”

 

Is it time to boost the level of federal involvement? If so, what role could government play? What non-government actions could be taken?


“Biophysical and Social Barriers Restrict Water Quality Improvements in the Mississippi River Basin”


Click here for the abstract.


*Journalists can request a PDF of the journal article by emailing newsroom@acs.org.


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Image credits: American Chemical Society (top), Jupiterimages/Photos.com/Thinkstock (bottom)