What Do You Think About Nanotechnology? Tell Us with Our Quick Survey – Pleeez!

Slate Nanotechnology Survey

Slate has recently published an online survey “Tell Us What You Think About Nanotechnology” (Follow the link above to take that survey).

Which … got us to thinking. “We” (Team GNT) should have our very own Survey on Nanotechnology with more focus on you … OUR READERS!

With over 5 Years of publication, 132,000+ hits on any average reporting cycle, representing Followers in over 50 Countries, and 10,000 plus Followers across Social Media … we are guessing you just might have some very “illuminating” and valuable thoughts, visions and opinions to share with us!

 

So … we are asking you to share your comments with us by answering a few questions and also … leaving us any ‘Open Comments’ you would care to leave. We will gather your responses, share the most interesting ones and let you know what others are “thinking and saying” about Nanotechnology. 

Questions Like

1. What Area or Application of Nanotechnology do you find most interesting? (Examples: Bio-Med, Cancer Treatment-Diagnosis, Electronics, Energy – Energy Storage, Materials, Sensors, Quantum Computing, etc.) Don’t let our suggestions limit your responses!

2. Which Areas or Applications do you think are most promising right now? In the future? that will dramatically change the World we live in?

3. Are you worried about the ‘safety’ of nanomaterials? On a scale of 1 to 10, 10 being MOST WORRIED. Why?

4. Which Nanotechnology Application or Area of Research interests you the most?

We have provided a ‘Response/ Contact Form’ for you below OR … you can Leave Us a Comment in the Comments Section. We are really looking forward to hearing from ALL of you!

Thanks! We are expecting … “Great Things from Small Things”!

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Researchers discover more efficient way to split water, produce hydrogen – U of Houston

llustration shows procedures for growing ternary molybdenum sulfoselenide on the porous foam; b-c, images showing surface roughness of the nickel diselenide foam grown at 600 degrees C; d-e, morphologies of ternary molybdenum sulfoselenide particles on porous foam, grown at 500 degrees C. Credit: University of Houston

Hydrogen is often considered a fuel for the future, in the form of fuel cells to power electric motors or burned in internal combustion engines. But finding a practical, inexpensive and nontoxic way to produce large amounts of hydrogen gas – especially by splitting water into its component parts, hydrogen and oxygen – has been a challenge.

A team of researchers from the University of Houston and the California Institute of Technology has reported a more efficient catalyst, using molybdenum sulfoselenide particles on three-dimensional porous nickel diselenide foam to increase catalytic activity.

The foam, made using commercially available nickel foam, significantly improved catalytic performance because it exposed more edge sites, where catalytic activity is higher than it is on flat surfaces, said Zhifeng Ren, MD Anderson Professor of physics at UH.

Ren is lead author of a paper in Nature Communications describing the discovery. Other researchers involved include Haiqing Zhou, Fang Yu, Jingying Sun, Ran He, Shuo Chen, Jiming Bao and Zhuan Zhu, all of UH, and Yufeng Huang, Robert J. Nielsen and William A. Goddard III of the California Institute of Technology.

“With the massive consumption of fossil fuels and its detrimental impact on the environment, methods of generating clean power are urgent,” the researchers wrote. “Hydrogen is an ideal carrier for renewable energy; however, hydrogen generation is inefficient because of the lack of robust catalysts that are substantially cheaper than platinum.”

Platinum catalysts have the highest efficiency rate for hydrogen evolution, said Ren, who also is a principal investigator at the Texas Center for Superconductivity. But platinum is rare, difficult to extract and too expensive for practical use, he said, and researchers continue to seek less expensive ways to split water into its component parts.
Currently, most hydrogen is produced through steam methane reforming and coal gasification; those methods raise the fuel’s carbon footprint despite the fact that it burns cleanly.

Molybdenum sulfoselenide and similar layered compounds have shown promise as catalysts, but so far no one has boosted their performance to viable levels in bulk form. The researchers say most active catalysis on those layered compounds, known as layered transition-metal dichalcogenides, or LTMDs, takes place at the edges, making the idea of a substrate with a large number of exposed edges more desirable. 
Also, they wrote, “arranging two different materials into hybrids might lead to synergistic effects that utilize the best properties of each component.”

Their hybrid catalyst is composed of molybdenum sulfoselenide particles with vertically aligned layers on a 3-D porous conductive nickel diselenide scaffold.
Testing determined that the hybrid catalyst required 69 millivolts from an external energy source to achieve a current density of 10 milliamps per square centimeter, which the researchers said is much better than many previously reported tests. 
In this case, the current “splits” the water, converting it to hydrogen at the cathode. Achieving the necessary current density with lower voltage improves energy conversion efficiency and reduces preparation costs.

A platinum catalyst required 32 millivolts in the testing, but Ren said ongoing testing has reduced the hybrid catalyst requirements to about 40 millivolts, close to the platinum requirements.

Equally important, he said, was the ability to increase current output at a faster rate than the increase in required energy input. The catalyst remained stable after 1,000 cycles at a constant current.

The work will continue as researchers focus on reducing required voltage.

More information: Haiqing Zhou et al. Efficient hydrogen evolution by ternary molybdenum sulfoselenide particles on self-standing porous nickel diselenide foam, Nature Communications (2016). DOI: 10.1038/ncomms12765
Provided by: University of Houston
Explore further
New catalyst for hydrogen production
Jul 27, 2016
With the aid of platinum catalysts, it is possible to efficiently produce hydrogen. However, this metal is rare and expensive. Researchers have discovered an alternative that is just as good, but less costly.

Quantum teleportation of a particle of light six kilometers – ‘Captain Kirk to Enterprise – Beam Us Up’

Distance record set for teleporting a photon over a fiber network

A group of physicists led by Wolfgang Tittel have successfully demonstrated teleportation of a photon, an elementary particle of light, over a straight-line distance of six kilometres.

Credit: Riley Brandt, University of Calgary

What if you could behave like the crew on the Starship Enterprise and teleport yourself home or anywhere else in the world? As a human, you’re probably not going to realize this any time soon; if you’re a photon, you might want to keep reading.

Through a collaboration between the University of Calgary, The City of Calgary and researchers in the United States, a group of physicists led by Wolfgang Tittel, professor in the Department of Physics and Astronomy at the University of Calgary have successfully demonstrated teleportation of a photon (an elementary particle of light) over a straight-line distance of six kilometres using The City of Calgary’s fibre optic cable infrastructure. The project began with an Urban Alliance seed grant in 2014.

This accomplishment, which set a new record for distance of transferring a quantum state by teleportation, has landed the researchers a spot in the journal Nature Photonics. The finding was published back-to-back with a similar demonstration by a group of Chinese researchers.

“Such a network will enable secure communication without having to worry about eavesdropping, and allow distant quantum computers to connect,” says Tittel.

Experiment draws on ‘spooky action at a distance’

The experiment is based on the entanglement property of quantum mechanics, also known as “spooky action at a distance” — a property so mysterious that not even Einstein could come to terms with it.

“Being entangled means that the two photons that form an entangled pair have properties that are linked regardless of how far the two are separated,” explains Tittel. “When one of the photons was sent over to City Hall, it remained entangled with the photon that stayed at the University of Calgary.” 

Next, the photon whose state was teleported to the university was generated in a third location in Calgary and then also travelled to City Hall where it met the photon that was part of the entangled pair.

“What happened is the instantaneous and disembodied transfer of the photon’s quantum state onto the remaining photon of the entangled pair, which is the one that remained six kilometres away at the university,” says Tittel.

City’s accessible dark fibre makes research possible

The research could not be possible without access to the proper technology. One of the critical pieces of infrastructure that support quantum networking is accessible dark fibre. Dark fibre, so named because of its composition — a single optical cable with no electronics or network equipment on the alignment — doesn’t interfere with quantum technology.

The City of Calgary is building and provisioning dark fibre to enable next-generation municipal services today and for the future.

“By opening The City’s dark fibre infrastructure to the private and public sector, non-profit companies, and academia, we help enable the development of projects like quantum encryption and create opportunities for further research, innovation and economic growth in Calgary,” said Tyler Andruschak, project manager with Innovation and Collaboration at The City of Calgary.

“The university receives secure access to a small portion of our fibre optic infrastructure and The City may benefit in the future by leveraging the secure encryption keys generated out of the lab’s research to protect our critical infrastructure,” said Andruschak. In order to deliver next-generation services to Calgarians, The City has been increasing its fibre optic footprint, connecting all City buildings, facilities and assets.

Timed to within one millionth of one millionth of a second

As if teleporting a photon wasn’t challenging enough, Tittel and his team encountered a number of other roadblocks along the way.

Due to changes in the outdoor temperature, the transmission time of photons from their creation point to City Hall varied over the course of a day — the time it took the researchers to gather sufficient data to support their claim. This change meant that the two photons would not meet at City Hall.

“The challenge was to keep the photons’ arrival time synchronized to within 10 pico-seconds,” says Tittel. “That is one trillionth, or one millionth of one millionth of a second.”

Secondly, parts of their lab had to be moved to two locations in the city, which as Tittel explains was particularly tricky for the measurement station at City Hall which included state-of-the-art superconducting single-photon detectors developed by the National Institute for Standards and Technology, and NASA’s Jet Propulsion Laboratory.

“Since these detectors only work at temperatures less than one degree above absolute zero the equipment also included a compact cryostat,” said Tittel.

Milestone towards a global quantum Internet

This demonstration is arguably one of the most striking manifestations of a puzzling prediction of quantum mechanics, but it also opens the path to building a future quantum internet, the long-term goal of the Tittel group.

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Story Source:

Materials provided by University of Calgary. Original written by Drew Scherban, University Relations. Note: Content may be edited for style and length.

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Journal References:

1. Raju Valivarthi, Marcel.li Grimau Puigibert, Qiang Zhou, Gabriel H. Aguilar, Varun B. Verma, Francesco Marsili, Matthew D. Shaw, Sae Woo Nam, Daniel Oblak, Wolfgang Tittel. Quantum teleportation across a metropolitan fibre network. Nature Photonics, 2016; DOI:10.1038/nphoton.2016.180
2. Qi-Chao Sun, Ya-Li Mao, Si-Jing Chen, Wei Zhang, Yang-Fan Jiang, Yan-Bao Zhang, Wei-Jun Zhang, Shigehito Miki, Taro Yamashita, Hirotaka Terai, Xiao Jiang, Teng-Yun Chen, Li-Xing You, Xian-Feng Chen, Zhen Wang, Jing-Yun Fan, Qiang Zhang, Jian-Wei Pan. Quantum teleportation with independent sources and prior entanglement distribution over a network. Nature Photonics, 2016; DOI:10.1038/nphoton.2016.179

Stanford U. – Iron nanoparticles make immune cells attack cancer

A mouse study found that ferumoxytol prompts immune cells called tumor-associated macrophages to destroy tumor cells. Credit: Amy Thomas

Stanford researchers accidentally discovered that iron nanoparticles invented for anemia treatment have another use: triggering the immune system’s ability to destroy tumor cells.

Iron nanoparticles can activate the immune system to attack cancer cells, according to a study led by researchers at the Stanford University School of Medicine.

The nanoparticles, which are commercially available as the injectable iron supplement ferumoxytol, are approved by the Food and Drug Administration to treat iron deficiency anemia.

The mouse study found that ferumoxytol prompts immune cells called tumor-associated macrophages to destroy cancer cells, suggesting that the nanoparticles could complement existing cancer treatments. The discovery, described in a paper published online Sept. 26 in Nature Nanotechnology, was made by accident while testing whether the nanoparticles could serve as Trojan horses by sneaking chemotherapy into tumors in mice.

“It was really surprising to us that the nanoparticles activated macrophages so that they started to attack cancer cells in mice,” said Heike Daldrup-Link, MD, who is the study’s senior author and an associate professor of radiology at the School of Medicine. “We think this concept should hold in human patients, too.”

Daldrup-Link’s team conducted an experiment that used three groups of mice: an experimental group that got nanoparticles loaded with chemo, a control group that got nanoparticles without chemo and a control group that got neither. The researchers made the unexpected observation that the growth of the tumors in control animals that got nanoparticles only was suppressed compared with the other controls.

Getting macrophages back on track

The researchers conducted a series of follow-up tests to characterize what was happening. Experimenting with cells in a dish, they showed that immune cells called tumor-associated macrophages were required for the nanoparticles’ anti-cancer activity; in cell cultures without macrophages, the iron nanoparticles had no effect against cancer cells.

Before this study was done, it was already known that in healthy people, tumor-associated macrophages detect and eat individual tumor cells. However, large tumors can hijack the tumor-associated macrophages, causing them to stop attacking and instead begin secreting factors that promote the cancer’s growth.

The study showed that the iron nanoparticles switch the macrophages back to their cancer-attacking state, as evidenced by tracking the products of the macrophages’ metabolism and examining their patterns of gene expression.

Furthermore, in a mouse model of breast cancer, the researchers demonstrated that the ferumoxytol inhibited tumor growth when given in doses, adjusted for body weight, similar to those approved by the FDA for anemia treatment. Prior studies had shown that the nanoparticles are metabolized over a period of about six weeks, and the new study showed that the anti-cancer effect of a single dose of nanoparticles declined over about three weeks.

The scientists also tested whether the nanoparticles could stop cancer from spreading. In a mouse model of small-cell lung cancer, the nanoparticles reduced tumor formation in the liver, a common site of metastasis in both mice and humans. In a separate model of liver metastasis, pretreatment with nanoparticles before tumor cells were introduced greatly reduced the volume of liver tumors.

Potential clinical applications

The study’s results suggest several possible applications to test in human trials, Daldrup-Link said. For instance, after surgery to remove a potentially metastatic tumor, patients often need chemotherapy but must wait until they recover from the operation to tolerate the severe side effects of conventional chemo. The iron nanoparticles lack the toxic side effects of chemotherapy, suggesting they might be given to patients during the surgical recovery period.

“We think this could bridge the time when the patient is quite sick after surgery, and help keep the cancer from spreading until they are able to receive chemotherapy,” said Daldrup-Link.

The nanoparticles may also help cancer patients whose tumors can’t be completely removed. “If there are some tumor cells left after surgery, the situation that cancer surgeons call positive margins, we think it might work to inject iron nanoparticles there, and the smaller tumor seeds could potentially be taken care of by our immune system,” Daldrup-Link said.

The fact that the nanoparticles are already FDA-approved speeds the ability to test these applications in humans, she added.

The new findings will also help cancer researchers conduct more accurate evaluations of nanoparticle-drug combinations, Daldrup-Link said. “In many studies, researchers just consider nanoparticles as drug vehicles,” she said. “But they may have hidden intrinsic effects that we won’t appreciate unless we look at the nanoparticles themselves.”

Explore further: Nanoparticles target and kill cancer stem cells that drive tumor growth

More information: Iron oxide nanoparticles inhibit tumour growth by inducing pro-inflammatory macrophage polarization in tumour tissues, Nature Nanotechnology, nature.com/articles/doi:10.1038/nnano.2016.168

Journal reference: Nature Nanotechnology

Provided by: Stanford University Medical Center

 

Nanoparticles called C dots show ability to induce cell death in tumors

Credit: Cornell University

Nanoparticles known as Cornell dots, or C dots, have shown great promise as a therapeutic tool in the detection and treatment of cancer.

Now, the ultrasmall particles – developed more than a dozen years ago by Ulrich Wiesner, the Spencer T. Olin Professor of Engineering – have shown they can do something even better: kill cancer cells without attaching a cytotoxic drug.

A study led by Michelle Bradbury, director of intraoperative imaging at Memorial Sloan Kettering Cancer Center and associate professor of radiology at Weill Cornell Medicine, and Michael Overholtzer, cell biologist at MSKCC, in collaboration with Wiesner has thrown a surprising twist into the decadelong quest to bring C dots out of the lab and into use as a clinical therapy.

Their paper, “Ultrasmall Nanoparticles Induce Ferroptosis of Nutrient-Deprived Cancer Cells and Suppress Tumor Growth,” was published Sept. 26 in Nature Nanotechnology. The work details how C dots, administered in large doses and with the tumors in a state of nutrient deprivation, trigger a type of cell death called ferroptosis.

“If you had to design a nanoparticle for killing cancer, this would be exactly the way you would do it,” Wiesner said. “The particle is well tolerated in normally healthy tissue, but as soon as you have a tumor, and under very specific conditions, these particles become killers.”

“In fact,” Bradbury said, “this is the first time we have shown that the particle has intrinsic therapeutic properties.”

Wiesner’s fluorescent silica particles, as small as 5 nanometers in diameter, were originally designed to be used as diagnostic tools, attaching to cancer cells and lighting up to show a surgeon where the tumor cells are. Potential uses also included drug delivery and environmental sensing. A first-in-human clinical trial by the Food and Drug Administration, led by Bradbury, deemed the particles safe for humans.

In further testing of the particles over the last five years – including the last 13 months as a member of the Centers of Cancer Nanotechnology Excellence, a National Cancer Institute initiative established in August 2015 – Bradbury, Overholtzer, Wiesner and their collaborators made this major, unexpected finding.

When incubated with cancer cells at high doses – and, importantly, with cancer cells in a state of nutrient deprivation – Wiesner’s peptide-coated C dots show the ability to adsorb iron from the environment and deliver this into cancer cells. The peptide, called alpha-MSH, was developed by Thomas Quinn, professor of biochemistry at the University of Missouri.

This process triggers ferroptosis, a necrotic form of cell death involving plasma membrane rupture – different from the typical cell fragmentation found during a more commonly observed form of cell death called apoptosis.

“The original purpose for studying the dots in cells was to see how well larger concentrations would be tolerated without altering cellular function,” Overholtzer said. “While high concentrations were well-tolerated under normal conditions, we wanted to also know how cancer cells under stress might respond.”

To the group’s surprise, in 24 to 48 hours after the cancer cells were exposed to the dots, there was a “wave of destruction” throughout the entire cell culture, Wiesner said. Tumors also shrank when mice were administered multiple high dose injections without any adverse reactions, said Bradbury, co-director with Wiesner of the MSKCC-Cornell Center for Translation of Cancer Nanomedicines.

In the ongoing fight against a disease that kills millions worldwide annually – cancer has taken several in Wiesner’s family, making this also a personal crusade for him. Having another weapon can only help, Wiesner said.

“We’ve found another tool that people have not thought about at all so far,” he said. “This has changed our way of thinking about nanoparticles and what they could potentially do.”

Future work will focus on utilizing these particles in combination with other standard therapies for a given tumor type, Bradbury said, with the hope of further enhancing efficacy before testing in humans.

Researchers will also look to tailor the particle to target specific cancers. “It’s a matter of designing the particles with different attachments on them, so they’ll bind to the particular cancer we’re after,” Overholtzer said.

Explore further: Camera system aids cancer clinical trial (w/ Video)

More information: Sung Eun Kim et al. Ultrasmall nanoparticles induce ferroptosis in nutrient-deprived cancer cells and suppress tumour growth,Nature Nanotechnology (2016). DOI: 10.1038/nnano.2016.164

Journal reference: Nature Nanotechnology

 

 

MIT: Nanosensors could help determine tumors’ ability to remodel tissue – Nanosensors that can ‘profile’ tumors

MIT researchers have designed nanosensors that can profile tumors and may yield insight into how they will respond to certain therapies. Credit: Christine Daniloff/MIT

MIT researchers have designed nanosensors that can profile tumors and may yield insight into how they will respond to certain therapies. The system is based on levels of enzymes called proteases, which cancer cells use to remodel their surroundings.

Once adapted for humans, this type of sensor could be used to determine how aggressive a tumor is and help doctors choose the best treatment, says Sangeeta Bhatia, the John and Dorothy Wilson Professor of Health Sciences and Technology and Electrical Engineering and Computer Science and a member of MIT’s Koch Institute for Integrative Cancer Research.

“This approach is exciting because people are developing therapies that are protease-activated,” Bhatia says. “Ideally you’d like to be able to stratify patients based on their protease activity and identify which ones would be good candidates for these therapies.”

Once injected into the tumor site, the nanosensors are activated by a magnetic field that is harmless to healthy tissue. After interacting with and being modified by the target tumor proteins, the sensors are secreted in the urine, where they can be easily detected in less than an hour.

Bhatia and Polina Anikeeva, the Class of 1942 Associate Professor of Materials Science and Engineering, are the senior authors of the paper, which appears in the journal Nano Letters. The paper’s lead authors are Koch Institute postdoc Simone Schurle and graduate student Jaideep Dudani.

Heat and release

Tumors, especially aggressive ones, often have elevated protease levels. These enzymes help tumors spread by cleaving proteins that compose the extracellular matrix, which normally surrounds cells and holds them in place.

In 2014, Bhatia and colleagues reported using nanoparticles that interact with a type of protease known as matrix metalloproteinases (MMPs) to diagnose cancer. In that study, the researchers delivered nanoparticles carrying peptides, or short protein fragments, designed to be cleaved by the MMPs. If MMPs were present, hundreds of cleaved peptides would be excreted in the urine, where they could be detected with a simple paper test similar to a pregnancy test.

In the new study, the researchers wanted to adapt the sensors so that they could report on the traits of tumors in a known location. To do that, they needed to ensure that the sensors were only producing a signal from the target organ, unaffected by background signals that might be produced in the bloodstream. They first designed sensors that could be activated with light once they reached their target. That required the use of ultraviolet light, however, which doesn’t penetrate very far into tissue.

“We started thinking about what kinds of energy we might use that could penetrate further into the body,” says Bhatia, who is also a member of MIT’s Institute for Medical Engineering and Science.

To achieve that, Bhatia teamed up with Anikeeva, who specializes in using magnetic fields to remotely activate materials. The researchers decided to encapsulate Bhatia’s protease-sensing nanoparticles along with magnetic particles that heat up when exposed to an alternating magnetic field. The field is produced by a small magnetic coil that changes polarity some half million times per second.

The heat-sensitive material that encapsulates the particles disintegrates as the magnetic particles heat up, allowing the protease sensors to be released. However, the particles do not produce enough heat to damage nearby tissue.

“It has been challenging to examine tumor-specific protease activities from patients’ biofluids because these proteases are also present in blood and other organs,” says Ji Ho (Joe) Park, an associate professor of bio and brain engineering at the Korea Advanced Institute of Science and Technology.

“The strength of this work is the magnetothermally responsive protease nanosensors with spatiotemporal controllability,” says Park, who was not involved in the research. “With these nanosensors, the MIT researchers could assay protease activities involved more in tumor progression by reducing off-target activation significantly.”

Choosing treatments

In a study of mice, the researchers showed that they could use these particles to correctly profile different types of colon tumors based on how much protease they produce.

Cancer treatments based on proteases, now in clinical trials, consist of antibodies that target a tumor protein but have “veils” that prevent them from being activated before reaching the tumor. The veils are cleaved by proteases, so this therapy would be most effective for patients with high protease levels.

The MIT team is also exploring using this type of sensor to image cancerous lesions that spread to the liver from other organs. Surgically removing such lesions works best if there are fewer than four, so measuring them could help doctors choose the best treatment.

Bhatia says this type of sensor could be adapted to other tumors as well, because the magnetic field can penetrate deep into the body. This approach could also be expanded to make diagnoses based on detecting other kinds of enzymes, including those that cut sugar chains or lipids.

Explore further: Nanoparticles amplify tumor signals, making them much easier to detect in the urine

More information: Simone Schuerle et al. Magnetically Actuated Protease Sensors for in Vivo Tumor Profiling, Nano Letters (2016). DOI: 10.1021/acs.nanolett.6b02670

Journal reference: Nano Letters

Provided by: Massachusetts Institute of Technology

 

 

Ontario government scraps plan for $3.8 billion in renewable energy projects – Is this a harbinger of things to come?

The move will keep $2.45 from going on the average homeowner’s monthly hydro bill.

Ontario is blowing off plans for more wind and solar power as it feels the heat over high electricity bills less than two years before a provincial election.

In its latest effort to curb prices, Premier Kathleen Wynne’s government is axing plans to sign another $3.8 billion in renewable energy contracts, Energy Minister Glenn Thibeault said Tuesday.

The move — which the Progressive Conservatives have demanded for years — will prevent $2.45 from being added to the average homeowner’s monthly hydro bill in the coming years.

Thibeault called it a “common sense” decision after the province’s electricity planning agency recently advised there is no “urgent need” for additional supply given Ontario’s surplus of generating capacity.

“I’ve been tasked to find ways to bring bills down,” said Thibeault, who was appointed minister last June. “When our experts said we didn’t need it, that’s when I acted.”

There may be more measures to come, Thibeault hinted in a speech prepared for the Ontario Energy Association on Tuesday night.

He pledged to “take a prudent look at every policy decision that has been made and determine if there is work we can do to reduce costs to Ontarians.”

The projects scrapped Tuesday would have created up to 1,000 megawatts of power, just under one-third of the 3,500 megawatts the four-unit Darlington nuclear power station produces near Oshawa.

 

Progressive Conservative Leader Patrick Brown called the suspension “too little, too late” while former Liberal energy minister George Smitherman and environmentalists suggested the government should have taken aim at costly nuclear refurbishments.

“Ontario had a choice to look forward but it chose to look backwards,” Smitherman said in a statement.

“The cancellation of the Large Renewable Procurement (LRP II) program makes it a scapegoat for pricing when the real culprit for oversupply is the aging Pickering nuclear plant.”

Ontario is planning to keep Pickering open until 2024 to provide electricity while it spends $12.8 billion refurbishing Darlington.

Green Party Leader Mike Schreiner said “the Liberals have chosen the wrong target,” echoing comments from the David Suzuki Foundation and Environmental Defence that the renewable cancellation is “short-sighted.”

“If you’re concerned about cost, you do more renewables and less nuclear,” said Gideon Forman from the foundation, noting the suspension will cost jobs in the green energy sector.

The Canadian Wind Energy Association warned cancelling the renewables will make it harder for Ontario to meet its greenhouse gas reduction targets in the battle against climate change.

Thibeault insisted the government is not “backtracking” on green energy because previously signed renewable contracts will go ahead in the province, eventually providing 18,000 megawatts of green energy. He said 90 per cent of generation, including nuclear, is emissions-free.

Sixteen projects — five wind, seven solar and four hydroelectric — approved last winter are proceeding and expected to create 455 megawatts of generating capacity.

That means ratepayers will still be on the hook for “energy we don’t need,” said Brown.

“They’ve made a huge mistake on the energy file . . . bills are still going to go up.”

NDP Leader Andrea Horwath blamed increasing privatization of the electricity system for steadily rising prices in the last decade, leaving Ontarians “paying the freight.”

The Liberal government, lagging in the polls, announced in its throne speech two weeks ago that the 8 per cent provincial tax on electricity will come off bills starting in January.

Many rural homeowners who face high delivery charges for hydro will also see 20 per cent savings, and 1,000 more companies will be able to take advantage of a program that allows them to shift hydro use away from periods of peak demand in return for lower prices.

That’s in addition to a hydro subsidy plan for low-income residents called the Ontario Electricity Support Program already in place.

Wynne and her MPPs were shadowed by wind farm protesters last week at the International Plowing Match and booed over hydro prices by some in attendance.

Thibeault downplayed the hostile reception.

“I was booed as a politician before. It’s something that comes with the job, right? My previous experience as a hockey referee helped me with the boos,” Thibeault told reporters Tuesday.

Also Tuesday, the provincial Financial Accountability Office released a report that found households in Toronto and Niagara typically spend the least on home energy costs and confirmed that northern Ontario residents spend the most, with low-income families facing the highest burden.

We want to know what YOU think. Is a “practical” decision like this, based on “which way the political wind is blowing” (pardon the pun) make sense in the short term? Long term? Leave us your Comments. We always like hearing from you! – Team GNT

St. Mary’s College Maryland: New research puts us closer to DIY Spray-on Solar Cell Technology

This Technology Announcement appeared in our Blog One Year ago. Find out where they are today. – Team GNT

Follow This Link: https://sites.google.com/a/smcm.edu/townsend-research-group/

Genesis Nanotechnologyo and l o

A new study out of St. Mary’s College of Maryland puts us closer to do-it-yourself spray-on solar cell technology — promising third-generation solar cells utilizing a nanocrystal ink deposition that could make traditional expensive silicon-based solar panels a thing of the past.

In a 2014 study, published in the journal Physical Chemistry Chemical Physics, St. Mary’s College of Maryland energy expert Professor Troy Townsend introduced the first fully solution-processed all-inorganic photovoltaic technology.

While progress on organic thin-film photovoltaics is rapidly growing, inorganic devices still hold the record for highest efficiencies which is in part due to their broad spectral absorption and excellent electronic properties. Considering the recorded higher efficiencies and lower cost per watt compared to organic devices, combined with the enhanced thermal and photo stability of bulk-scale inorganic materials, Townsend, in his 2014 study, focused on an all-inorganic based structure for fabrication of a top to bottom fully…

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(Cadmium) Telluride Promising Alternative to Silicon: Crystalline fault lines provide pathway for solar cell current (w/video) [U Conn and Brookhaven NL]

** From Brookhaven National Laboratory & Nanowerk   A team of scientists studying solar cells made from cadmium telluride, a promising alternative to silicon, has discovered that microscopic “fault lines” within and between crystals of the material act as conductive pathways that ease the flow of electric current. This research—conducted at the University of Connecticut and the U.S. Department of Energy’s Brookhaven National Laboratory, and described in the journal Nature Energy (“Charge transport in CdTe solar cells revealed by conductive tomographic atomic force microscopy”), may help explain how a common processing technique turns cadmium telluride into an excellent material for transforming sunlight into electricity, and suggests a strategy for engineering more efficient solar devices that surpass the performance of silicon.

“If you look at semiconductors like silicon, defects in the crystals are usually bad,” said co-author Eric Stach, a physicist at Brookhaven Lab’s Center for Functional Nanomaterials (CFN). As Stach explained, misplaced atoms or slight shifts in their alignment often act as traps for the particles that carry electric current—negatively charged electrons or the positively charged “holes” left behind when electrons are knocked loose by photons of sunlight, making them more mobile. The idea behind solar cells is to separate the positive and negative charges and run them through a circuit so the current can be used to power houses, satellites, or even cities. Defects interrupt this flow of charges and keep the solar cell from being as efficient as it could be.

But in the case of cadmium telluride, the scientists found that boundaries between individual crystals and “planar defects”—fault-like misalignments in the arrangement of atoms—create pathways for conductivity, not traps.

These CTAFM images show a cadmium telluride solar cell from the top (above) and side profile (bottom) with bright spots representing areas of higher electron conductivity. The images reveal that the conductive pathways coincide with crystal grain boundaries. (Image: University of Connecticut)

Members of Bryan Huey’s group at the Institute of Materials Science at the University of Connecticut were the first to notice the surprising connection. In an effort to understand the effects of a chloride solution treatment that greatly enhances cadmium telluride’s conductive properties, Justin Luria and Yasemin Kutes studied solar cells before and after treatment. But they did so in a unique way.

Several groups around the world had looked at the surfaces of such solar cells before, often with a tool known as a conducting atomic force microscope. The microscope has a fine probe many times sharper than the head of a pin that scans across the material’s surface to track the topographic features—the hills and valleys of the surface structure—while simultaneously measuring location-specific conductivity. Scientists use this technique to explore how the surface features relate to solar cell performance at the nanoscale.

But no one had devised a way to make measurements beneath the surface, the most important part of the solar cell. This is where the UConn team made an important breakthrough. They used an approach developed and perfected by Kutes and Luria over the last two years to acquire hundreds of sequential images, each time intentionally removing a nanoscale layer of the material, so they could scan through the entire thickness of the sample. They then used these layer-by-layer images to build up a three-dimensional, high-resolution ‘tomographic’ map of the solar cell—somewhat like a computed tomography (CT) brain scan.

Assembling the layer-by-layer CTAFM scans into a side-profile video file reveals the relationship between conductivity and planar defects throughout the entire thickness of the cadmium telluride crystal, including how the defects appear to line up to form continuous pathways of conductivity. (Video: University of Connecticut)

“Everyone using these microscopes basically takes pictures of the ‘ground,’ and interprets what is beneath,” Huey said. “It may look like there’s a cave, or a rock shelf, or a building foundation down there. But we can only really know once we carefully dig, like archeologists, keeping track of exactly what we find every step of the way—though, of course, at a much, much smaller scale.”

The resulting CT-AFM maps uniquely revealed current flowing most freely along the crystal boundaries and fault-like defects in the cadmium telluride solar cells. The samples that had been treated with the chloride solution had more defects overall, a higher density of these defects, and what appeared to be a high degree of connectivity among them, while the untreated samples had few defects, no evidence of connectivity, and much lower conductivity.

Huey’s team suspected that the defects were so-called planar defects, usually caused by shifts in atomic alignments or stacking arrangements within the crystals. But the CTAFM system is not designed to reveal such atomic-scale structural details. To get that information, the UConn team turned to Stach, head of the electron microscopy group at the CFN, a DOE Office of Science User Facility.

“Having previously shared ideas with Eric, it was a natural extension of our discovery to work with his group,” Huey said.

Said Stach, “This is the exact type of problem the CFN is set up to handle, providing expertise and equipment that university researchers may not have to help drive science from hypothesis to discovery.”

CFN staff physicist Lihua Zhang used a transmission electron microscope (TEM) and UConn’s results as a guide to meticulously study how atomic scale features of chloride-treated cadmium telluride related to the conductivity maps. The TEM images revealed the atomic structure of the defects, confirming that they were due to specific changes in the stacking sequence of atoms in the material. The images also showed clearly that these planar defects connected different grains in the crystal, leading to high-conductivity pathways for the movement of electrons and holes.

“When we looked at the regions with good conductivity, the planar defects linked from one crystal grain to another, forming continuous pathways of conductance through the entire thickness of the material,” said Zhang. “So the regions that had the best conductivity were the ones that had a high degree of connectivity among these defects.”

These transmission electron microscopy images taken at Brookhaven’s CFN reveals how the stacking pattern of individual atoms (bright spots) shifts. The images confirmed that the bright spots of high conductivity observed with CTAFM imaging at UConn occurred at the interfaces between two different atomic alignments (left) and that these “planar defects” were continuous between individual crystals, creating pathways of conductivity (right). The labels WZ and ZB refer to the two atomic stacking sequences “wurtzite” and “zinc blende,” which are the two types of crystal structures cadmium telluride can form. (click on image to enlarge)

The authors say it’s possible that the chloride treatment helps to create the connectivity, not just more defects, but that more research is needed to definitively determine the most significant effects of the chloride solution treatment.

In any case, Stach says that combining the CTAFM technique and electron microscopy, yields a “clear winner” in the search for more efficient, cost-competitive alternatives to silicon solar cells, which have nearly reached their limit for efficiency.

“There is already a billion-dollar-a-year industry making cadmium telluride solar cells, and lots of work exploring other alternatives to silicon. But all of these alternatives, because of their crystal structure, have a higher tendency to form defects,” he said. “This work gives us a systematic method we can use to understand if the defects are good or bad in terms of conductivity. It can also be used to explore the effects of different processing methods or chemicals to control how defects form. In the case of cadmium telluride, we may want to find ways to make more of these defects, or look for other materials in which defects improve performance.”

Source: Brookhaven National Laboratory

 

MIT: Powering up graphene implants without frying cells ~ For the Next Generation of Implants

This computational illustration shows a graphene network structure below a layer of water.

Image: Zhao Qin

New analysis finds way to safely conduct heat from graphene to biological tissues.

In the future, our health may be monitored and maintained by tiny sensors and drug dispensers, deployed within the body and made from graphene — one of the strongest, lightest materials in the world. Graphene is composed of a single sheet of carbon atoms, linked together like razor-thin chicken wire, and its properties may be tuned in countless ways, making it a versatile material for tiny, next-generation implants.

But graphene is incredibly stiff, whereas biological tissue is soft. Because of this, any power applied to operate a graphene implant could precipitously heat up and fry surrounding cells.

Now, engineers from MIT and Tsinghua University in Beijing have precisely simulated how electrical power may generate heat between a single layer of graphene and a simple cell membrane. While direct contact between the two layers inevitably overheats and kills the cell, the researchers found they could prevent this effect with a very thin, in-between layer of water.

By tuning the thickness of this intermediate water layer, the researchers could carefully control the amount of heat transferred between graphene and biological tissue. They also identified the critical power to apply to the graphene layer, without frying the cell membrane. The results are published today in the journal Nature Communications.

Co-author Zhao Qin, a research scientist in MIT’s Department of Civil and Environmental Engineering (CEE), says the team’s simulations may help guide the development of graphene implants and their optimal power requirements.

“We’ve provided a lot of insight, like what’s the critical power we can accept that will not fry the cell,” Qin says. “But sometimes we might want to intentionally increase the temperature, because for some biomedical applications, we want to kill cells like cancer cells. This work can also be used as guidance [for those efforts.]”

Qin’s co-authors include Markus Buehler, head of CEE and the McAfee Professor of Engineering, along with Yanlei Wang and Zhiping Xu of Tsinghua University.

Sandwich model

Typically, heat travels between two materials via vibrations in each material’s atoms. These atoms are always vibrating, at frequencies that depend on the properties of their materials. As a surface heats up, its atoms vibrate even more, causing collisions with other atoms and transferring heat in the process.

The researchers sought to accurately characterize the way heat travels, at the level of individual atoms, between graphene and biological tissue. To do this, they considered the simplest interface, comprising a small, 500-nanometer-square sheet of graphene and a simple cell membrane, separated by a thin layer of water.

“In the body, water is everywhere, and the outer surface of membranes will always like to interact with water, so you cannot totally remove it,” Qin says. “So we came up with a sandwich model for graphene, water, and membrane, that is a crystal clear system for seeing the thermal conductance between these two materials.”

Qin’s colleagues at Tsinghua University had previously developed a model to precisely simulate the interactions between atoms in graphene and water, using density functional theory — a computational modeling technique that considers the structure of an atom’s electrons in determining how that atom will interact with other atoms.

However, to apply this modeling technique to the group’s sandwich model, which comprised about half a million atoms, would have required an incredible amount of computational power. Instead, Qin and his colleagues used classical molecular dynamics — a mathematical technique based on a “force field” potential function, or a simplified version of the interactions between atoms — that enabled them to efficiently calculate interactions within larger atomic systems.

The researchers then built an atom-level sandwich model of graphene, water, and a cell membrane, based on the group’s simplified force field. They carried out molecular dynamics simulations in which they changed the amount of power applied to the graphene, as well as the thickness of the intermediate water layer, and observed the amount of heat that carried over from the graphene to the cell membrane.

Watery crystals

Because the stiffness of graphene and biological tissue is so different, Qin and his colleagues expected that heat would conduct rather poorly between the two materials, building up steeply in the graphene before flooding and overheating the cell membrane. However, the intermediate water layer helped dissipate this heat, easing its conduction and preventing a temperature spike in the cell membrane.

Looking more closely at the interactions within this interface, the researchers made a surprising discovery: Within the sandwich model, the water, pressed against graphene’s chicken-wire pattern, morphed into a similar crystal-like structure.

“Graphene’s lattice acts like a template to guide the water to form network structures,” Qin explains. “The water acts more like a solid material and makes the stiffness transition from graphene and membrane less abrupt. We think this helps heat to conduct from graphene to the membrane side.”

The group varied the thickness of the intermediate water layer in simulations, and found that a 1-nanometer-wide layer of water helped to dissipate heat very effectively. In terms of the power applied to the system, they calculated that about a megawatt of power per meter squared, applied in tiny, microsecond bursts, was the most power that could be applied to the interface without overheating the cell membrane.

Qin says going forward, implant designers can use the group’s model and simulations to determine the critical power requirements for graphene devices of different dimensions. As for how they might practically control the thickness of the intermediate water layer, he says graphene’s surface may be modified to attract a particular number of water molecules. 

“I think graphene provides a very promising candidate for implantable devices,” Qin says. “Our calculations can provide knowledge for designing these devices in the future, for specific applications, like sensors, monitors, and other biomedical applications.”

This research was supported in part by the MIT International Science and Technology Initiative (MISTI): MIT-China Seed Fund, the National Natural Science Foundation of China, DARPA, the Department of Defense (DoD) Office of Naval Research, the DoD Multidisciplinary Research Initiatives program, the MIT Energy Initiative, and the National Science Foundation.