Novel C. diff structures are required for infection, offer new therapeutic targets

 Iron storage "spheres" inside the bacterium C. diff -- the leading cause of hospital-acquired infections -- could offer new targets for antibacterial drugs to combat the pathogen.

A team of Vanderbilt researchers discovered that C. diff (Clostridioides difficile) produces the spheres, called ferrosomes, and that these structures are important for infection in an animal model. The findings, reported Nov. 15 in the journal Nature, are also a rare demonstration of a membrane-bound structure inside a pathogenic bacterium.

Bacteria have long been thought not to contain organelles (such as a nucleus, mitochondria and other specialized structures) like eukaryotic cells, but that biological dogma appears to be incorrect.

"The emerging idea that bacteria do compartmentalize biochemical processes in a way similar to eukaryotic cells really flips the field of microbiology on its head," said Eric Skaar, PhD, MPH, the Ernest W. Goodpasture Professor of Pathology and director of the Vanderbilt Institute for Infection, Immunology, and Inflammation.

Skaar, co-corresponding author Qiangjun Zhou, PhD, assistant professor of Cell and Developmental Biology, and their colleagues were intrigued by findings reported several years ago that some environmental bacteria produce iron-containing ferrosomes.

They knew that the genes in these bacteria were conserved in C. diff and other anaerobic bacteria (bacteria that die in the presence of oxygen), and they set out to determine if C. diff produces ferrosomes to manage its need for iron. Like all living organisms, C. diff requires iron to survive and grow. Skaar and his team have focused on how pathogens like C. diff acquire iron and other metals, with a goal of finding new pathways that could be exploited to "starve" pathogens of essential nutrients.

C. diff causes about 500,000 infections and more than 29,000 deaths in the United States each year, according to the Centers for Disease Control and Prevention, and treatment options are limited. People taking antibiotics that disrupt the healthy microbes in the gut are at increased risk for C. diff infection, which causes diarrhea and colitis. New strategies for treating this urgent public health threat are needed, Skaar said.

To look for iron inside C. diff, the researchers first drew on expertise and resources in the Vanderbilt Institute of Nanoscale Science and Engineering (VINSE).

"The best way to look for the accumulation of elements in a small space like a cell is with a method called STEM-EDS, which has not commonly been used for biological samples," Skaar said. "We were fortunate to have access to a STEM-EDS instrument and collaborators at VINSE, and we quickly proved that there was an accumulation of iron 'dots' within the bacterium."

Co-first authors Hualiang Pi, PhD, and Rong Sun, PhD, led studies to show that those iron dots represented organelles that were important to C. diff infection.

Pi and Skaar's team found that two genes (fezA and fezB), which are similar to those in environmental bacteria, were required for ferrosome formation. Using C. diff bacteria missing these genes, they showed that ferrosomes are required for C. diff to fully colonize and cause disease in an animal model. They found that ferrosomes were even more important for C. diff infection in a model of inflammatory bowel disease, demonstrating that these iron-containing structures help the bacterium combat "nutritional immunity" -- the host response of producing proteins to bind iron and attempt to starve the pathogen.

Sun and Zhou's team used cryogenic electron microscopy (cryo-EM) and cryo-tomography to show that the ferrosome structures were encased in a membrane, classifying them as organelles.

Skaar noted that "Vanderbilt's unique geography" -- the proximity of experts in engineering, cell biology and the Medical Center -- and specialized tools for STEM-EDS and cryo-EM made the research possible.

The results "establish ferrosome formation and all the factors involved in ferrosome formation as potential targets for new antibacterial drugs against an important infectious disease," Skaar said. "Anytime we find new factors involved in host-pathogen interactions and show that they're important for infection, that opens entirely new opportunities to make classes of antibacterial drugs that have not existed before. That is especially important in the face of rising antimicrobial resistance that we're seeing globally."

In future studies, the researchers plan to explore how ferrosomes are formed, whether other gut pathogens produce ferrosomes, and whether these structures might be shared in the gut as a source of iron. Skaar is also particularly interested in pursuing the emerging area of bacterial organelles.

"We think our study is a rare demonstration of an organelle in a pathogenic bacterium," he said. "Now we want to know if there are other subcellular compartments in bacteria that we're interested in that could teach us about how these cells perform various physiologic processes."

Scientists 3D-print hair follicles in lab-grown skin

 A team led by scientists at Rensselaer Polytechnic Institute has 3D-printed hair follicles in human skin tissue cultured in the lab. This marks the first time researchers have used the technology to generate hair follicles, which play an important role in skin healing and function.

The finding, published in the journal Science Advances, has potential applications in regenerative medicine and drug testing, though engineering skin grafts that grow hair are still several years away.

"Our work is a proof-of-concept that hair follicle structures can be created in a highly precise, reproducible way using 3D-bioprinting. This kind of automated process is needed to make future biomanufacturing of skin possible," said Pankaj Karande, Ph.D., an associate professor of chemical and biological engineering and a member of Rensselaer's Shirley Ann Jackson, Ph.D. Center for Biotechnology and Interdisciplinary Studies, who led the study.

"The reconstruction of hair follicles using human-derived cells has historically been a challenge. Some studies have shown that if these cells are cultured in a three-dimensional environment, they can potentially originate new hair follicles or hair shafts, and our study builds on this work," Karande said.

When it comes to engineering human skin, hair may at first seem superfluous. However, hair follicles are quite important: They produce sweat, helping regulate body temperature, and they contain stem cells that help skin heal.

Hair follicles are also an entry point for topical drugs and cosmetics, making them an important part of dermatological testing. But today, initial safety testing is done on engineered skin tissues that lack hair follicles.

"Right now, contemporary skin models -- the engineered structures that mimic human skin -- are quite simple. Increasing their complexity by adding hair follicles would give us even more information about how skin interacts with topical products," said Carolina Catarino, Ph.D., first author of the study, who earned her doctorate at Rensselaer and is now a researcher developing new skin testing methods at Grupo Boticário, a cosmetics company in her home country of Brazil.

"Dr. Karande's lab is at the forefront of skin tissue engineering. This team has already successfully printed skin with working blood vessels, and this latest research is an exciting next step in developing and testing better treatments for burns and other skin conditions," said Deepak Vashishth, Ph.D., director of the Shirley Ann Jackson, Ph.D. Center for Biotechnology and Interdisciplinary Studies.

"Dr. Karande's work is a great example of advances being made by RPI researchers at the interface of engineering and life sciences with impact on human health," said Shekhar Garde, Ph.D., dean of Rensselaer's School of Engineering. "Bringing multichannel 3-D printing to biological realm is opening exciting opportunities that would have been hard to imagine in the past."

The researchers created their follicle-bearing skin with 3D-printing techniques adapted for printing at the cellular level.

The scientists begin by allowing samples of skin and follicle cells to divide and multiply in the lab until there are enough printable cells. Next, the researchers mix each type of cell with proteins and other materials to create the "bio-ink" used by the printer. Using an extremely thin needle to deposit the bio-ink, the printer builds the skin layer by layer, while also creating channels for depositing the hair cells. Over time, the skin cells migrate to these channels surrounding the hair cells, mirroring the follicle structures present in real skin.

Right now, these tissues have a lifespan of two to three weeks, which is not enough time for hair shafts to develop. The research team's future work aims to extend that period, allowing the hair follicle to mature further and paving the way for their use in drug testing and skin grafts.

Realistic talking faces created from only an audio clip and a person's photo

 A team of researchers from Nanyang Technological University, Singapore (NTU Singapore) has developed a computer program that creates realistic videos that reflect the facial expressions and head movements of the person speaking, only requiring an audio clip and a face photo.

DIverse yet Realistic Facial Animations, or DIRFA, is an artificial intelligence-based program that takes audio and a photo and produces a 3D video showing the person demonstrating realistic and consistent facial animations synchronised with the spoken audio (see videos).

The NTU-developed program improves on existing approaches, which struggle with pose variations and emotional control.

To accomplish this, the team trained DIRFA on over one million audiovisual clips from over 6,000 people derived from an open-source database called The VoxCeleb2 Dataset to predict cues from speech and associate them with facial expressions and head movements.

The researchers said DIRFA could lead to new applications across various industries and domains, including healthcare, as it could enable more sophisticated and realistic virtual assistants and chatbots, improving user experiences. It could also serve as a powerful tool for individuals with speech or facial disabilities, helping them to convey their thoughts and emotions through expressive avatars or digital representations, enhancing their ability to communicate.

Corresponding author Associate Professor Lu Shijian, from the School of Computer Science and Engineering (SCSE) at NTU Singapore, who led the study, said: "The impact of our study could be profound and far-reaching, as it revolutionises the realm of multimedia communication by enabling the creation of highly realistic videos of individuals speaking, combining techniques such as AI and machine learning. Our program also builds on previous studies and represents an advancement in the technology, as videos created with our program are complete with accurate lip movements, vivid facial expressions and natural head poses, using only their audio recordings and static images."

First author Dr Wu Rongliang, a PhD graduate from NTU's SCSE, said: "Speech exhibits a multitude of variations. Individuals pronounce the same words differently in diverse contexts, encompassing variations in duration, amplitude, tone, and more. Furthermore, beyond its linguistic content, speech conveys rich information about the speaker's emotional state and identity factors such as gender, age, ethnicity, and even personality traits. Our approach represents a pioneering effort in enhancing performance from the perspective of audio representation learning in AI and machine learning." Dr Wu is a Research Scientist at the Institute for Infocomm Research, Agency for Science, Technology and Research (A*STAR), Singapore.

The findings were published in the scientific journal Pattern Recognition in August.

Speaking volumes: Turning audio into action with animated accuracy

The researchers say that creating lifelike facial expressions driven by audio poses a complex challenge. For a given audio signal, there can be numerous possible facial expressions that would make sense, and these possibilities can multiply when dealing with a sequence of audio signals over time.

Since audio typically has strong associations with lip movements but weaker connections with facial expressions and head positions, the team aimed to create talking faces that exhibit precise lip synchronisation, rich facial expressions, and natural head movements corresponding to the provided audio.

To address this, the team first designed their AI model, DIRFA, to capture the intricate relationships between audio signals and facial animations. The team trained their model on more than one million audio and video clips of over 6,000 people, derived from a publicly available database.

Assoc Prof Lu added: "Specifically, DIRFA modelled the likelihood of a facial animation, such as a raised eyebrow or wrinkled nose, based on the input audio. This modelling enabled the program to transform the audio input into diverse yet highly lifelike sequences of facial animations to guide the generation of talking faces."

Dr Wu added: "Extensive experiments show that DIRFA can generate talking faces with accurate lip movements, vivid facial expressions and natural head poses. However, we are working to improve the program's interface, allowing certain outputs to be controlled. For example, DIRFA does not allow users to adjust a certain expression, such as changing a frown to a smile."

Besides adding more options and improvements to DIRFA's interface, the NTU researchers will be finetuning its facial expressions with a wider range of datasets that include more varied facial expressions and voice audio clips.

New compound outperforms pain drug by indirectly targeting calcium channels

 A compound -- one of 27 million screened in a library of potential new drugs -- reversed four types of chronic pain in animal studies, according to new research led by NYU College of Dentistry's Pain Research Center and published in the Proceedings of the National Academy of Sciences (PNAS).

The small molecule, which binds to an inner region of a calcium channel to indirectly regulate it, outperformed gabapentin without troublesome side effects, providing a promising candidate for treating pain.

Calcium channels play a central role in pain signaling, in part through the release of neurotransmitters such as glutamate and GABA -- "the currency of the pain signal," according to Rajesh Khanna, director of the NYU Pain Research Center and professor of molecular pathobiology at NYU Dentistry. The Cav2.2 (or N-type) calcium channel is the target for three clinically available drugs, including gabapentin (sold under brand names including Neurontin) and pregabalin (Lyrica), which are widely used to treat nerve pain and epilepsy.

Gabapentin mitigates pain by binding to the outside of the Cav2.2 calcium channel, affecting the channel's activity. However, like many pain medications, gabapentin use often comes with side effects.

"Developing effective pain management with minimal side effects is crucial, but creating new therapies has been challenging," said Khanna, the senior author of the PNAS study. "Rather than directly going after known targets for pain relief, our lab is focused on indirectly targeting proteins that are involved in pain."

Inside the channel

Khanna has long been interested in a protein called CRMP2, a key regulator of the Cav2.2 calcium channel that binds to the channel from the inside. He and his colleagues previously discovered a peptide (a small region of amino acids) derived from CRMP2 that could uncouple CRMP2 from the calcium channel. When this peptide -- dubbed the calcium channel-binding domain 3, or CBD3 -- was delivered to cells, it acted as a decoy, blocking CRMP2 from binding to the inside of the calcium channel. This resulted in less calcium entering the calcium channel and less neurotransmitter release, which translated to less pain in animal studies.

Peptides are difficult to synthesize as drugs because they are short-acting and easily degrade in the stomach, so the researchers sought to create a small molecule drug based on CBD3. Starting with the 15 amino acids that make up the CBD3 peptide, they honed in on two amino acids that studies showed were responsible for inhibiting calcium influx and mitigating pain.

"At that point, we realized that these two amino acids could be the building blocks for designing a small molecule," said Khanna.

From 27 million to one

In collaboration with colleagues at the University of Pittsburgh, the researchers ran a computer simulation that screened a library of 27 million compounds to look for a small molecule that would "match" the CBD3 amino acids.

The simulation narrowed the library down to 77 compounds, which the researchers experimentally tested to see if they lessened the amount of calcium influx. This further pared the pool down to nine compounds, which were assessed using electrophysiology to measure decreases in electrical currents through the calcium channels.

One compound, which the researchers named CBD3063, emerged as the most promising candidate for treating pain. Biochemical tests revealed that CBD3063 disrupted the interaction between the CaV2.2 calcium channel and CRMP2 protein, reduced calcium entering the channel, and lessened the release of neurotransmitters.

"Many scientists have screened the same library of compounds, but have been trying to block the calcium channel from the outside. Our target, these two amino acids from CRMP2, is on the inside of the cell, and this indirect approach may be the key to our success," said Khanna.

Four labs, four types of pain

Khanna's lab then tested CBD3063 with mouse models for pain related to injury. The compound was effective in alleviating pain in both male and female mice -- and notably, in a head-to-head test with the drug gabapentin, the researchers needed to use far less CBD3063 (1 to 10 mg) than gabapentin (30 mg) to reduce pain.

To explore whether CBD3063 helped with different types of chronic pain, Khanna partnered with researchers at Virginia Commonwealth University, Michigan State University, and Rutgers University. Collaborators ran similar studies administering CBD3063 to treat animal models of chemotherapy-induced neuropathy, inflammatory pain, and trigeminal nerve pain -- all successfully reversing pain, similar to gabapentin.

But unlike gabapentin, the use of CBD3063 did not come with side effects, including sedation, changes to cognition such as memory and learning, or changes to heart rate and breathing.

What's next

The researchers are continuing to study CBD3063, refining its chemical composition and running additional tests to study the compound's safety and assess if tolerance develops.

Long-term, they hope to bring a CBD3063-derived drug to clinical trials in an effort to offer new options for safe and effective pain relief.

"Identifying this first-in-class small molecule has been the culmination of more than 15 years of research. Though our research journey continues, we aspire to present a superior successor to gabapentin for the effective management of chronic pain," said Khanna.

Additional authors include Kimberly Gomez, Tyler Nelson, Heather Allen, Aida Calderon-Rivera, Sara Hestehave, Erick Rodríguez Palma, Paz Duran, Santiago Loya-Lopez, Samantha Perez-Miller, and May Khanna of NYU Dentistry's Pain Research Center; Elaine Zhu and Jing Wang of NYU Grossman School of Medicine; Handoko and Paramjit Arora of NYU's Department of Chemistry; Ulises Santiago and Carlos Camacho of the University of Pittsburgh; Yuan Zhou, Angie Dorame, and Aude Chefdeville of the University of Arizona; Upasana Kumar, Rory Shields, Wanhong Zuo, Huijuan Hu, and Olga Korczeniewska of Rutgers University; Eda Koseli, Bryan McKiver, and M. Imad Damaj of Virginia Commonwealth University; Denise Giuvelis and Tamara King of the University of New England; Kufreobong Inyang and Geoffroy Laumet of Michigan State University; Dongzhi Ran, Yi Lu, and Xia Liu of Chongqing Medical University; Marcel Patek of Bright Rock Path LLC; and Aubin Moutal of St. Louis University.

This 3D printer can watch itself fabricate objects

 With 3D inkjet printing systems, engineers can fabricate hybrid structures that have soft and rigid components, like robotic grippers that are strong enough to grasp heavy objects but soft enough to interact safely with humans.

These multimaterial 3D printing systems utilize thousands of nozzles to deposit tiny droplets of resin, which are smoothed with a scraper or roller and cured with UV light. But the smoothing process could squish or smear resins that cure slowly, limiting the types of materials that can be used.

Researchers from MIT, the MIT spinout Inkbit, and ETH Zurich have developed a new 3D inkjet printing system that works with a much wider range of materials. Their printer utilizes computer vision to automatically scan the 3D printing surface and adjust the amount of resin each nozzle deposits in real time to ensure no areas have too much or too little material.

Since it does not require mechanical parts to smooth the resin, this contactless system works with materials that cure more slowly than the acrylates which are traditionally used in 3D printing. Some slower-curing material chemistries can offer improved performance over acrylates, such as greater elasticity, durability, or longevity.

In addition, the automatic system makes adjustments without stopping or slowing the printing process, making this production-grade printer about 660 times faster than a comparable 3D inkjet printing system.

The researchers used this printer to create complex, robotic devices that combine soft and rigid materials. For example, they made a completely 3D-printed robotic gripper shaped like a human hand and controlled by a set of reinforced, yet flexible, tendons.

"Our key insight here was to develop a machine vision system and completely active feedback loop. This is almost like endowing a printer with a set of eyes and a brain, where the eyes observe what is being printed, and then the brain of the machine directs it as to what should be printed next," says co-corresponding author Wojciech Matusik, a professor of electrical engineering and computer science at MIT who leads the Computational Design and Fabrication Group within the MIT Computer Science and Artificial Intelligence Laboratory (CSAIL).

He is joined on the paper by lead author Thomas Buchner, a doctoral student at ETH Zurich, co-corresponding author Robert Katzschmann, PhD '18, assistant professor of robotics who leads the Soft Robotics Laboratory at ETH Zurich; as well as others at ETH Zurich and Inkbit. The research will appear in Nature.

Contact free

This paper builds off a low-cost, multimaterial 3D printer known as MultiFab that the researchers introduced in 2015. By utilizing thousands of nozzles to deposit tiny droplets of resin that are UV-cured, MultiFab enabled high-resolution 3D printing with up to 10 materials at once.

With this new project, the researchers sought a contactless process that would expand the range of materials they could use to fabricate more complex devices.

They developed a technique, known as vision-controlled jetting, which utilizes four high-frame-rate cameras and two lasers that rapidly and continuously scan the print surface. The cameras capture images as thousands of nozzles deposit tiny droplets of resin.

The computer vision system converts the image into a high-resolution depth map, a computation that takes less than a second to perform. It compares the depth map to the CAD (computer-aided design) model of the part being fabricated, and adjusts the amount of resin being deposited to keep the object on target with the final structure.

The automated system can make adjustments to any individual nozzle. Since the printer has 16,000 nozzles, the system can control fine details of the device being fabricated.

"Geometrically, it can print almost anything you want made of multiple materials. There are almost no limitations in terms of what you can send to the printer, and what you get is truly functional and long-lasting," says Katzschmann.

The level of control afforded by the system enables it to print very precisely with wax, which is used as a support material to create cavities or intricate networks of channels inside an object. The wax is printed below the structure as the device is fabricated. After it is complete, the object is heated so the wax melts and drains out, leaving open channels throughout the object.

Because it can automatically and rapidly adjust the amount of material being deposited by each of the nozzles in real time, the system doesn't need to drag a mechanical part across the print surface to keep it level. This enables the printer to use materials that cure more gradually, and would be smeared by a scraper.

Superior materials

The researchers used the system to print with thiol-based materials, which are slower-curing than the traditional acrylic materials used in 3D printing. However, thiol-based materials are more elastic and don't break as easily as acrylates. They also tend to be more stable over a wider range of temperatures and don't degrade as quickly when exposed to sunlight.

"These are very important properties when you want to fabricate robots or systems that need to interact with a real-world environment," says Katzschmann.

The researchers used thiol-based materials and wax to fabricate several complex devices that would otherwise be nearly impossible to make with existing 3D printing systems. For one, they produced a functional, tendon-driven robotic hand that has 19 independently actuatable tendons, soft fingers with sensor pads, and rigid, load-bearing bones.

"We also produced a six-legged walking robot that can sense objects and grasp them, which was possible due to the system's ability to create airtight interfaces of soft and rigid materials, as well as complex channels inside the structure," says Buchner.

The team also showcased the technology through a heart-like pump with integrated ventricles and artificial heart valves, as well as metamaterials that can be programmed to have non-linear material properties.

"This is just the start. There is an amazing number of new types of materials you can add to this technology. This allows us to bring in whole new material families that couldn't be used in 3D printing before," Matusik says.

New deep learning AI tool helps ecologists monitor rare birds through their songs

 Researchers have developed a new deep learning AI tool that generates life-like birdsongs to train bird identification tools, helping ecologists to monitor rare species in the wild. The findings are presented in the British Ecological Society journal, Methods in Ecology and Evolution.

Identifying common bird species through their song has never been easier, with numerous phone apps and software available to both ecologists and the public. But what if the identification software has never heard a particular bird before, or only has a small sample of recordings to reference? This is a problem facing ecologists and conservationists monitoring some of the world's rarest birds.

To overcome this problem, researchers at the University of Moncton, Canada, have developed ECOGEN, a first of its kind deep learning tool, that can generate lifelike bird sounds to enhance the samples of underrepresented species. These can then be used to train audio identification tools used in ecological monitoring, which often have disproportionately more information on common species.

The researchers found that adding artificial birdsong samples generated by ECOGEN to a birdsong identifier improved the bird song classification accuracy by 12% on average.

Dr Nicolas Lecomte, one of the lead researchers, said: "Due to significant global changes in animal populations, there is an urgent need for automated tools, such acoustic monitoring, to track shifts in biodiversity. However, the AI models used to identify species in acoustic monitoring lack comprehensive reference libraries.

"With ECOGEN, you can address this gap by creating new instances of bird sounds to support AI models. Essentially, for species with limited wild recordings, such as those that are rare, elusive, or sensitive, you can expand your sound library without further disrupting the animals or conducting additional fieldwork."

The researchers say that creating synthetic bird songs in this way can contribute to the conservation of endangered bird species and also provide valuable insight into their vocalisations, behaviours and habitat preferences.

The ECOGEN tool has other potential applications. For instance, it could be used to help conserve extremely rare species, like the critically endangered regent honeyeaters, where young individuals are unable to learn their species' songs because there aren't enough adult birds to learn from.

The tool could benefit other types of animal as well. Dr Lecomte added: "While ECOGEN was developed for birds, we're confident that it could be applied to mammals, fish (yes they can produce sounds!), insects and amphibians."

As well as its versatility, a key advantage of the ECOGEN tool is its accessibility, due to it being open source and able to used on even basic computers.

ECOGEN works by converting real recordings of bird songs into spectrograms (visual representations of sounds) and then generating new AI images from these to increase the dataset for rare species with few recordings. These spectrograms are then converted back into audio to train bird sound identifiers. In this study the researchers used a dataset of 23,784 wild bird recordings from around the world, covering 264 species.

Ammonia for fertilizers without the giant carbon footprint

 The production of ammonia for fertilisers -- which has one of the largest carbon footprints among industrial processes -- will soon be possible on farms using low-cost, low-energy and environmentally friendly technology.

This is thanks to researchers at UNSW Sydney and their collaborators who have developed an innovative technique for sustainable ammonia production at scale.

Up until now, the production of ammonia has relied on high-energy processes that leave a massive global carbon footprint -- temperatures of more than 400 oC and pressures exceeding 200 atmospheres that account for 2 per cent of the world's energy and 1.8 per cent of its CO2.

But the researchers have come up with a method that significantly enhances energy efficiency while making environmentally friendly ammonia economically feasible. The new technique eliminates the requirement for high temperatures, high pressure, and extensive infrastructure in ammonia production.

In a paper published recently in the journal Applied Catalysis B: Environmental, the authors show that the process they developed has enabled the large-scale synthesis of green ammonia by increasing its energy efficiency and production rate.

The foundation of this research, previously published by the same research group, has already been licensed to an Australian industry partner, PlasmaLeap Technologies, through the UNSW Knowledge Exchange program. It is set to be translated into the Australian agriculture industry, with a prototype already scaled up and ready for deployment.

The latest study follows on from the proof-of-concept research performed by the same UNSW research group three years ago with significant advances in energy efficiency and production rate in the process, thus improving commercial profitability.

The research also represents an opportunity to use green ammonia in the hydrogen transport market, as liquid ammonia (NH3) can store more hydrogen in a smaller space than liquefied hydrogen (H2), making the transportation of hydrogen energy more economical.

Net zero objectives

While the conventional process used for ammonia production is notably energy-intensive -- relying heavily on fossil fuels as its primary energy and hydrogen sources -- it has been instrumental in increasing crop yields and sustaining a growing global population.

Dr. Ali Jalili, the study's leader and a former Australian Research Council DECRA Fellow at UNSW, says adopting a sustainable approach to ammonia production is crucial for global net zero objectives.

"Currently, the traditional method of producing ammonia -- known as the Haber-Bosch process -- accounts for 2.4 tonnes of CO2 per tonne of ammonia, equivalent to approximately 2 per cent of global carbon emissions. Additionally, Haber-Bosch is economically viable only in large-scale and centralised facilities. Consequently, the transportation from these facilities to farms will increase the CO2 emission by 50 per cent," he says.

"Ammonia-based fertilisers are in critically short supply due to international supply chain disruptions and geopolitical issues, which impact our food security and production costs.

"This, together with its potential for hydrogen energy storage and transportation, makes ammonia key to Australia's renewable energy initiatives, positioning the country among the leaders in renewable energy exports and utilisation."

As well as addressing economic and logistical challenges associated with intermittent energy sources for cities or farms, Dr Jalili says to fully unlock its potential, it is "essential to establish a decentralised and energy-efficient production method that can effectively use surplus renewable electricity."

Researchers develop gel to deliver cancer drugs for solid tumors

 Intratumoral therapy -- in which cancer drugs are injected directly into tumors -- is a promising treatment option for solid cancers but has shown limited success in clinical trials due to an inability to precisely deliver the drug and because most immunotherapies quickly dissipate from the site of injection. A team of researchers from Mass General Brigham, in collaboration with colleagues at the Koch Institute for Integrative Cancer Research, has developed a gel delivery system that overcomes these challenges. The gel is injectable but solidifies upon delivery; contains an imaging agent for visualization under CT scan; and can hold a high concentration of drug for slow, controlled release.

In a paper published in Advanced Healthcare Materials, the team reports that using gel-delivered imiquimod (an immune stimulating drug) in combination with checkpoint inhibitor therapy induced tumor regression and increased survival in mouse models of colon and breast cancer that are usually resistant to checkpoint inhibitor therapy. The treatment also appeared to train the immune system to detect and attack distant tumors that were not directly treated, suggesting that it might be a helpful therapy for metastatic cancers.

"This gel tackles the two problems with existing attempts at making intratumoral cancer immunotherapy: making the therapy visible and practical so that interventional radiologists can confirm delivery, and making sure the drug actually stays in the region of interest," said Avik Som, MD, PhD, of the Department of Radiology at Massachusetts General Hospital, a founding member of the Mass General Brigham healthcare system. "When we inject this gel into a tumor, we're able to teach the immune system to recognize the cancer and trigger it to attack not only the site where the gel was injected, but also other areas in the body where the same cancer may be hiding."

The research team, which consisted of both engineers and medical professionals, first developed and optimized the gel-delivery system in the lab by tweaking the gel's chemical structure. One key aspect of the gel's design was that it needed to shift from being liquid at room temperature to make it injectable but become solid at body temperature inside the tumor in order to form a drug-releasing depot, while also retaining drug encapsulation and delivery capability, and carrying sufficient imaging agent.

After optimizing the gel in the lab, the team tested its ability to treat mouse models of colon and breast cancer that are usually resistant to immunotherapy. To do this, they used the gel to deliver imiquimod, an FDA-approved immune stimulating drug, in combination with checkpoint inhibitor therapy. Each mouse had two tumors of the same type, but the researchers only treated one tumor per mouse, which allowed them to test the gel's ability to stimulate both local and systemic immunity.

They showed that treating with gel-delivered imiquimod in combination with checkpoint inhibitor therapy improved survival in both cancer models. The treatment resulted in an all-or-nothing response -- mice that responded to the treatment showed complete regression of both the treated tumor and a distantly located tumor (a model for metastasis), while non-responders showed no regression at either site. For the colon cancer model, 46% (6/13) survived when the checkpoint inhibitor therapy was combined with gel-delivered imiquimod. For the breast cancer model, 20% (3/15) survived when treated with the combined therapies.

"These two tumors remain challenging to treat today, even though immunotherapies are transforming how we think about treatment," said co-corresponding author Giovanni Traverso, MB, PhD, MBBCH, Department of Medicine at Brigham and Women's Hospital, a founding member of the Mass General Brigham healthcare system and an associate professor in the Department of Mechanical Engineering at MIT. "The fact that we were able to induce responses in distant tumors in these colon and breast cancer models was a big win."

How human faces can teach androids to smile

 Robots able to display human emotion have long been a mainstay of science fiction stories. Now, Japanese researchers have been studying the mechanical details of real human facial expressions to bring those stories closer to reality.

In a recent study published by the Mechanical Engineering Journal, a multi-institutional research team led by Osaka University have begun mapping out the intricacies of human facial movements. The researchers used 125 tracking markers attached to a person's face to closely examine 44 different, singular facial actions, such as blinking or raising the corner of the mouth.

Every facial expression comes with a variety of local deformation as muscles stretch and compress the skin. Even the simplest motions can be surprisingly complex. Our faces contain a collection of different tissues below the skin, from muscle fibers to fatty adipose, all working in concert to convey how we're feeling. This includes everything from a big smile to a slight raise of the corner of the mouth. This level of detail is what makes facial expressions so subtle and nuanced, in turn making them challenging to replicate artificially. Until now, this has relied on much simpler measurements, of the overall face shape and motion of points chosen on skin before and after movements.

"Our faces are so familiar to us that we don't notice the fine details," explains Hisashi Ishihara, main author of the study. "But from an engineering perspective, they are amazing information display devices. By looking at people's facial expressions, we can tell when a smile is hiding sadness, or whether someone's feeling tired or nervous."

Information gathered by this study can help researchers working with artificial faces, both created digitally on screens and, ultimately, the physical faces of android robots. Precise measurements of human faces, to understand all the tensions and compressions in facial structure, will allow these artificial expressions to appear both more accurate and natural.

"The facial structure beneath our skin is complex," says Akihiro Nakatani, senior author. "The deformation analysis in this study could explain how sophisticated expressions, which comprise both stretched and compressed skin, can result from deceivingly simple facial actions."

This work has applications beyond robotics as well, for example, improved facial recognition or medical diagnoses, the latter of which currently relies on doctor intuition to notice abnormalities in facial movement.

So far, this study has only examined the face of one person, but the researchers hope to use their work as a jumping off point to gain a fuller understanding of human facial motions. As well as helping robots to both recognize and convey emotion, this research could also help to improve facial movements in computer graphics, like those used in movies and video games, helping to avoid the dreaded 'uncanny valley' effect.

New drug-like molecule extends lifespan, ameliorates pathology in worms and boosts function in mammalian muscle cells

 Having healthy mitochondria, the organelles that produce energy in all our cells, usually portends a long healthy life whether in humans or in C. elegans, a tiny, short-lived nematode worm often used to study the aging process. Researchers at the Buck Institute have identified a new drug-like molecule that keeps mitochondria healthy via mitophagy, a process that removes and recycles damaged mitochondria in multicellular organisms. The compound, dubbed MIC, is a natural compound that extended lifespan in C. elegans, ameliorated pathology in neurodegenerative disease models of C. elegans, and improved mitochondrial function in mouse muscle cells. Results are published in the November 13, 2023, edition of Nature Aging.

The impact of mitochondrial dysfunction in age-related disease

Defective mitophagy is implicated in many age-related diseases. It's tied to neurodegenerative disorders such as Parkinson's and Alzheimer's; it plays a role in cardiovascular diseases including heart failure; it influences metabolic disorders including obesity and type 2 diabetes; it is implicated in muscle wasting and sarcopenia and has a complex relationship with cancer progression. Even though interventions that restore mitophagy and facilitate the elimination of damaged mitochondria hold great promise for addressing these conditions, not one treatment has been approved for human use despite advances in the field.

What's MIC?

MIC (Mitophagy-Inducing Compound) is a coumarin, which are naturally bioactive compounds that have anticoagulant, antibacterial, antifungal, antiviral, anticancer, and antihyperglycemic properties (among others) as well as being an antioxidant with neuroprotective effects. Coumarin is found in many plants and is found in high concentrations in certain types of cinnamon, which is one of the most frequent sources for human exposure to the substance.

A new mechanism of action in mitophagy

The project started in a mouse model of Parkinson's disease where researchers in the laboratory of Julie Andersen, PhD, a senior author of the paper, were looking at known enhancers of mitophagy, including rapamycin. "Co-author Shankar Chinta, PhD, started screening natural compounds in neuronal cells and MIC came up as a major hit," she said. "Rather than taking MIC immediately into a mouse model we wanted to understand its impact on overall aging and identify its mechanism of action, so we took the work into the worm where we found that MIC is in a different class of molecules that enhance the expression of a key protein, TFEB."

In an effort spearheaded by Andersen and research scientist Manish Chamoli, PhD, lead author of the study, researchers found that MIC enhanced the activity of transcription factor TFEB, which is a master regulator of genes involved in autophagy and lysosomal functions. Autophagy is the intracellular recycling process whereby cells clean up damaged proteins; it derives its abilities from the lysosome. Researchers found that MIC robustly increased the lifespan of C. elegans while also preventing mitochondrial dysfunction in mammalian cells.

"This paper helps support the overall notion of TFEB being a key autophagy regulator that extends lifespan, "said Buck professor and Chief Scientific Officer Malene Hansen, PhD, who collaborated on the paper. She added, "Mitophagy is a selective and very significant form of autophagy. The field has recognized TFEB as a player when it comes to quality control in mitochondria. This study provides a possible translational route to induce mitophagy in a TFEB-dependent fashion."

A link to the brain/gut connection

Mechanistically MIC works upstream of TFEB by inhibiting ligand-induced activation of the nuclear hormone receptor DAF-12 (in worms)/FXR (in humans), which in turn induces mitophagy and extends lifespan. FXR is best known for its ability to act in the liver and gut to maintain lipid homeostasis, where it acts to regulate levels of TFEB as part of a feed-fast cycle, but recently TFEB was shown to also be present in brain neurons. This provided Andersen with the clue needed to piece together MIC's potential mechanism of action in the latter. "This study provides another piece of the puzzle when it comes to understanding the brain/gut connection in terms of health and disease," said Andersen

FXR is regulated by bile salts which are formed in the gut microbiome. "The gut microbiome impacts the body's use of bile acids. Aging impacts our microbiome," said Chamoli. "If levels of bile acids aren't correct it hinders mitophagy. That's how FXR can impact neuronal health. Neurons have a lot of mitochondria which makes mitophagy important in terms of neurodegeneration," he said, noting that experiments are underway to explore neuronal FXR as a therapeutic target for Alzheimer's disease as part of a jointly funded grant shared by the Andersen and Lithgow labs.

MIC as a general geroprotective therapeutic

"There's a bottleneck in efforts to develop potential therapeutics in the field of geroscience, and the bottleneck is that we don't have enough molecules in the pipeline," said Gordon Lithgow, PhD, Buck Professor and Vice President of Academic Affairs and senior co-author. "MIC is a great candidate to bring forward given its therapeutic effect across multiple models and the fact that it is a naturally occurring molecule."

Chamoli highlighted the direct links between mitophagy and aging, suggesting that drugs enhancing this process could offer treatment well beyond neurodegeneration or muscle wasting. He added, "All these possibilities can be explored at the Buck where the research environment supports such endeavors."

Antiviral treatment is largely underused in children with influenza, study findings show

 Despite national medical guidelines supporting the use of antiviral medications in young children diagnosed with influenza, a new study reports an underuse of the treatment.

"Trends in Outpatient Influenza Antiviral Use Among Children and Adolescents in the United States" was published in Pediatrics, a peer-reviewed journal of the American Academy of Pediatrics.

"Antiviral treatment, when used early, improves health outcomes with influenza," said lead author and principal investigator James Antoon, MD, PhD, MPH, assistant professor of Pediatrics and Hospital Medicine at Monroe Carell Jr. Children's Hospital at Vanderbilt.

Antoon and colleagues collaborated with researchers from the University of Illinois at Chicago on a large study examining outpatient and emergency department prescription claims for patients younger than 18 from all 50 states over a nine-year period.

Oseltamivir, also known at Tamiflu, is the only oral antiviral medication approved for use in children younger than 5 years old.

"We found that young children, less than 5 years old and especially those 2 years old and younger, are undertreated for influenza," said Antoon. "We noted that about 40% of children were treated with an antiviral, when guidelines recommend all of them be treated. It's important to note that we found low rates of antiviral use in all age groups."

The study also found wide geographic variation in the use of influenza antivirals -- there was a threefold to twentyfold difference in the rate of antiviral use based on geographic region that was not explained by differences in the incidence of flu, said Antoon.

"These findings highlight opportunities for improvement in the prevention and treatment of influenza, especially in the most vulnerable children," he added.

Potential reasons for underprescribing in children include a wide range of perceptions about efficacy, differences in interpretation of testing, a misunderstanding of the national guidelines and concern for adverse drug events associated with oseltamivir in children.

A previous 2023 study, led by Antoon, explored how often children diagnosed with influenza experience serious neuropsychiatric side effects.

In that study, Antoon and his team were able to quantify the number of pediatric neuropsychiatric events, describe which children are more likely to experience the events and showed that these relatively infrequent events occur in both those children treated and not treated with an antiviral.

"Treatment of children in the outpatient setting has been reported to decrease symptom duration, household transmission, antibiotic use and influenza- associated complications like ear infections," said Antoon.

The low rate of antiviral use in young children captured in the study along with recent evidence of low guideline-concordant antiviral treatment in children at high risk for influenza complications highlight the need for improved flu management in the most vulnerable children in the U.S., according to the study.

The study was funded by grants K23AI168496 from the National Institute of Allergy and Infectious Diseases (NIAID), which is part of the National Institutes of Health, an American Pediatrics Association Young Investigator Award and the Vanderbilt University Medical Center Turner Hazinski Research Award. Carlos Grijalva, MD, MPH, professor of Health Policy and Biomedical Informatics at Vanderbilt University Medical Center (K24AI148459) and Derek Williams, MD, MPH, chief of the Division of Hospital Medicine at Monroe Carell (RO1AI125642) both supported by the NIAID.

Are consumers ready for robots to show up at their doorstep?

 With Amazon aiming to make 10,000 deliveries with drones in Europe this year and Walmart planning to expand its drone delivery services to an additional 60,000 homes this year in the states, companies are investing more research and development funding into drone delivery, But are consumers ready to accept this change as the new normal?

Northwestern University's Mobility and Behavior Lab, led by Amanda Stathopoulos, an associate professor of civil and environmental engineering, wanted to know if consumers were ready for robots to replace delivery drivers, in the form of automated vehicles, drones and robots. The team found that societally, there's work to do to shift public perceptions of the near-future technology.

"We need to think really carefully about the effect of these new technologies on people and communities, and to tune in to what they think about these changes," Stathopoulos, the study's senior author, said.

The study, titled "Robots at your doorstep: Acceptance of near-future technologies for automated parcel delivery," published last week in the journal Scientific Reports. Researchers noted a "complex and multifaceted" relationship between behavior and acceptance of near-future technologies for automated parcel delivery.

While people were generally more willing to accept an automated vehicle as a substitute for a delivery person -- perhaps because there already is familiarity with self-driving cars -- people disliked drones and robots as options. However, as delivery speed increased and price decreased, likelihood to accept the technology increased.

They also found that tech-savvy consumers were more accepting of the near-future technologies than populations less familiar with the technology.

Stathopoulos is the William Patterson Junior professor of civil and environmental engineering at Northwestern's McCormick School of Engineering, where she studies the human aspects of new systems of mobility. She also is a faculty affiliate of Northwestern's Transportation Center. She said especially after the pandemic, people have come to expect efficient delivery from e-commerce purchases as they increasingly work from home.

Maher Said, a graduate of Stathopoulos's lab, is the study's lead author.

"There's a paradox: We're having a hard time reconciling the convenience and the benefit of getting speedy, efficient delivery with its consequences, like poor labor conditions in warehouses, air pollution and congested streets," Stathopoulos said. "We don't really see that other role that we play as citizens or as users of the city. And one role is directly affecting the other role, and we are both. With automated delivery, we could reduce some of these issues."

The team designed a survey to assess preferences of 692 U.S. respondents, asking questions about different delivery options and variables like delivery speed, package handling and general perceptions.

Stathopoulos said that while new modes of delivery present an exciting opportunity, societally, "we're not there just yet." As companies ramp up drone deliveries due in part to labor shortages and in part because existing systems cannot satisfy the sheer volume of e-commerce deliveries, the researchers caution that these innovations may fail because of a lack of public acceptance.

"On the planning side, we need to make sure that we embrace the fact that the massive amount of deliveries is going to shape our cities," Stathopoulos said. "Collaboration, coordination, and information sharing between companies has been a running challenge -- but it's not going to work if everyone has their own technology. It just destroys the purpose and builds redundant and overlapping systems."

However, by listening to and conducting more frequent assessments of user acceptance of technologies, Stathopoulos argues that policy makers and companies can prepare for the future and work to overcome anxiety and reluctance to accept new technologies.

The study was supported by the National Science Foundation Career program.

Shark fear: Just when you thought it was safe to get back in the water...

 It's one of the most famous taglines in film history, immortalising sharks as ruthless predators. But beyond the horror generated by Spielberg's Jaws series, a persistent fear of sharks remains, with consequences that extend into reality.

Following human-shark interactions in South Australia, this fear has prompted the Education Department's ban on school-based sea activities for at least the remainder of the term. And while safety is at the core of such decisions, we should be cautious of scaremongering, says UniSA shark expert Dr Brianna Le Busque.

"When we hear about shark "attacks," it definitely puts people on edge, especially when interactions and sightings are sensationalised by the media," Dr Le Busque says.

"As most people do not have personal interactions with sharks, most of what we know about sharks comes from what we see on TV or in movies. Movies such as Jaws, The Meg or The Shallows depict sharks as purposely hunting and attacking humans, which not only creates excessive fear but strengthens any negative views people may already hold.

"This is called the 'The Jaws Effect' -- a known phenomenon where people are excessively and irrationally scared of sharks -- today, nearly 50 years after the first Jaws movie, it still influences people's perceptions of sharks, impacts conservation efforts, and affects policy decisions.

"That's what we've seen with the current bans on sea-based water activities. And the problem is that it could have negative impacts on children's ideas of water and beach safety."

In a new UniSA world first study, Dr Le Busque shows how over-represented sharks are in the realm of 'creature features' -- a subgenre of science fiction, horror, or action films where the creatures are the villain in the plot.

"Sharks are commonplace in 'creature feature' films -- they overrepresented, being the most common animal in this film category. Further, of all films that depict sharks (in various genres) 96% overtly portrayed shark-human interactions as threatening."

In the past 50 years, oceanic sharks have declined by more than 70%, with one in three species now threatened by extinction.

Dr Le Busque says while she believes the bans on school activities are currently unwarranted, she welcomes the early deployment of aerial shark patrols.

"Earlier shark monitoring is a good move to protect beachgoers, but we need a balance between people's safety and access to the ocean," Dr Le Busque says.

"No one wants a shark attack to occur, but these bans are just creating the same fear as generated on the ill-fated Amity Island in Jaws. It's just not the right way to go."

CEO Surf Life Saving SA, Damien Marangon, says the ban on beach-based aquatic programs, without consultation or understanding facts and broader impact, was disappointing.

"Whilst the shark attack is incredibly unfortunate, it's also important to remember that tragically, far more people sadly drown every year in South Australian waters, than there are shark attacks," Marangon says.

"Over the past 20 years, we've averaged just over one instance per year. Despite the incidents over the last month or so, our data shows that we have not seen an increase in shark numbers.

"We were concerned about the impact this would have on the 3,899 students, from 47 schools who were enrolled in that program for the remainder of this term, who would not have had the opportunity to learn vital water safety skills, jeopardising their future safety in and around the water.

"Decisions like this, made in isolation, also unfortunately promote a fear of the ocean, which could have wide ranging and long-lasting impacts on our communities, local traders, family businesses, and the travel industry, by unnecessarily exacerbating a fear of our ocean, and will impact visitors to our beaches and our State.

"We're actively working with the Water Safety Unit within the Department for Education on strategies to continue to ensure that all participants can complete these aquatic education programs at the beach safely, and continue to make informed decisions based on data, research and stakeholder engagement."

When keeping secrets could brighten your day

 Though people often want to share good news as soon as they learn it, a study published by the American Psychological Association has found that keeping good news a secret before telling someone else could make people feel more energized and alive.

"Decades of research on secrecy suggest it is bad for our well-being, but this work has only examined keeping secrets that have negative implications for our lives. Is secrecy inherently bad for our well-being or do the negative effects of secrecy tend to stem from keeping negative secrets?" asked lead author Michael Slepian, PhD, an associate professor of business at Columbia University. "While negative secrets are far more common than positive secrets, some of life's most joyful occasions begin as secrets, including secret marriage proposals, pregnancies, surprise gifts and exciting news."

The research was published in the Journal of Personality and Social Psychology.

A pre-study survey of 500 people found that 76% said the first thing they would do upon learning good news is share it with someone. But there are many positive life events that people may choose to keep secret, such as a marriage proposal, a desired pregnancy or splurging on a luxury purchase.

Researchers conducted five experiments with more than 2,500 participants to understand what motivates people to keep positive secrets, and how keeping a positive secret may affect someone compared with a secret they keep because they consider it to be unpleasant or embarrassing.

In one experiment, participants were shown a list of nearly 40 common types of good news, which included items such as saving up money, buying a gift for oneself or reducing a debt. The participants then indicated which pieces of good news they currently had and which they had kept secret. Some participants were asked to reflect on the good news they kept secret, while others reflected on good news that was not secret, and then rated how energized the news made them feel and whether they intended to share the news with someone else.

The researchers found that people held on average 14 to 15 pieces of good news, with an average of five to six that were kept secret. The participants who reflected on their positive secrets reported feeling more energized than the participants who thought about their good news that was not secret. People who reported that they intended to share their news with others also reported feeling more energized, whether the news was secret or not.

"Positive secrets that people choose to keep should make them feel good, and positive emotion is a known predictor of feeling energized," said Slepian. But the researchers found across four follow-up studies that positive secrets make people feel energized for another reason too.

One of those experiments showed participants the list of common types of good news and asked them to select the piece of news that was most likely to happen to them in the near future. One group of participants then imagined that they kept the good news secret until they told their partner later that day while another group imagined that they were currently unable to reach their partner and so were not able to tell them until later in the day. When participants imagined wanting to hold the information back to make the revelation surprising, they were more energized than when they were unable to reveal the information.

Another experiment asked participants to recall a current positive secret (a secret they felt good about), a current negative secret (a secret they felt bad about) or simply a current secret. The researchers found that people keep positive secrets in particular for internal or personal reasons, rather than because they felt forced by outside pressures to keep the information secret.

In contrast to negative or embarrassing secrets, which are often governed by external pressures or fears, positive secrets made people feel enlivened when they could choose to keep the information secret, according to Slepian.

"People will often keep positive secrets for their own enjoyment, or to make a surprise more exciting. Rather than based in external pressures, positive secrets are more often chosen due to personal desires and internal motives," he said. "When we feel that our actions arise from our own desires rather than external pressures, we also feel ready to take on whatever lies ahead."

The researchers also found that keeping good news a secret can make people feel energized and alive, regardless of whether they intend to share that information later with someone or not.

"People sometimes go to great lengths to orchestrate revealing a positive secret to make it all the more exciting. This kind of surprise can be intensely enjoyable, but surprise is the most fleeting of our emotions," Slepian said. "Having extra time -- days, weeks or even longer -- to imagine the joyful surprise on another person's face allows us more time with this exciting moment, even if only in our own minds."