“We’re at the tipping point,” said electrical and computer engineering professor Daniel Blumenthal.

In an invited article that was also selected for the cover of Optica Quantum, Blumenthal, along with graduate student researcher Andrei Isichenko and postdoctoral researcher Nitesh Chauhan, lays out the latest developments and future directions for trapping and cooling the atoms that are fundamental to these experiments — and that will bring them to devices that fit in the palm of your hand.

Cold atoms are atoms that have been cooled to very low temperatures, below 1 mK, reducing their motion to a very low energy regime where quantum effects emerge. This makes them sensitive to some of the faintest electromagnetic signals and fundamental particles, as well as ideal timekeeping, navigation devices and quantum “qubits” for computing.

In order to capitalize on these properties, many researchers currently work with highly sensitive laboratory-scale atomic optical systems to confine, trap and cool the atoms. Conventionally, these systems use free-space lasers and optics, generating beams that are guided, directed and manipulated by lenses, mirrors and modulators. These optical systems are combined with magnetic coils and atoms in a vacuum to create cold atoms using the ubiquitous 3-dimensional magneto-optical trap (3D-MOT). The challenge that researchers face is how to replicate the laser and optics functions onto a small, durable device that could be deployed outside of the highly controlled environment of the lab, for applications such as gravitational sensing, precision timekeeping and metrology, and quantum computing

The Optica Quantum review article covers recent and rapid advancements in the realm of miniaturizing complex cold-atom experiments via applications of compact optics and integrated photonics. The authors reference photonics achievements across a variety of sub-fields, ranging from telecommunications to sensors, and map the technology development to cold atom science.

“There’s been a lot of really great work miniaturizing beam delivery,” said Isichenko, “but it’s been done with components that are still considered free-space optics — smaller mirrors or smaller gratings — but you still couldn’t integrate multiple functionalities onto a chip.”

Enter the researchers’ photonic integrated 3D-MOT, a miniaturized version of equipment used widely in experiments to deliver beams of light to laser cool the atoms. Embedded into a low-loss silicon nitride waveguide integration platform, it’s the part of a photonic system that generates, routes, expands and manipulates all the beams necessary to trap and cool the atoms. The review article highlights the photonic integrated 3D-MOT — or “PICMOT” demonstrated by the UC Santa Barbara team as a major milestone for the field.

“With photonics, we can make lasers on chip, modulators on chip and now large-area grating emitters, which is what we use to get light on and off the chip,” Isichenko added.

Of particular interest is the atomic cell, a vacuum chamber where the atoms are trapped and cooled. One feat the researchers accomplished was to route the input light from an optical fiber, which is less than the width of a hair, via waveguides to three grating emitters that generate three collimated free-space intersecting beams 3.5 mm wide. Each beam is reflected back on itself for a total of six intersecting beams that trap a million atoms from the vapor inside the cell and, in combination with magnetic fields, cool the atoms to a temperature of just 250 uK. The larger the beams the more atoms can be trapped into a cloud and interrogated, Blumenthal noted, and the more precise an instrument can be.

“We created cold atoms with integrated photonics for the first time,” said Blumenthal.

The implications of the researchers’ innovations are far-reaching. With planned improvements to durability and functionality, future chip-scale MOT designs can take advantage of a menu of photonic components, including recent results with chip-scale lasers. This can be used to optimize technology for applications as diverse as measuring volcanic activity to the effects of sea level rise and glacier movement by sensing the gradient of gravity on and around the Earth.

Integration of the 3D-MOT can give quantum scientists and time keepers new ways to send today’s earthbound instruments into space and conduct new fundamental science, and enable measurements not possible on Earth. Additionally, the devices could advance research projects by decreasing the time and effort spent establishing and fine tuning optical setups. They can also open the door to accessible quantum research projects for future physicists.

The study, published in Hypertension and supported by the National Institutes of Health, investigated whether mothers who reported higher perceived stress and depressive symptoms during pregnancy, developed higher blood pressure in the four-year period after birth. The findings showed higher stress and depressive symptoms during pregnancy were associated with greater blood pressure during the first year postpartum, but associations diminished thereafter.

“Pregnancy is a complex time where women experience different physiological changes,” says Noelle Pardo, the lead author of the study and third year doctoral student in the Department of Population and Public Health Sciences at Keck School of Medicine. “This study is building on maternal health research to understand how stressors impact women’s lives and their health after pregnancy.”

The study included data from 225 mothers from the MADRES pregnancy cohort which primarily consists of Hispanic women, and low-income participants living in Los Angeles. Hispanic women have a high burden of cardiovascular risk, and there is growing evidence linking psychosocial stressors to poor cardiovascular health, which is a leading cause of death among women in the US.

In addition to prenatal psychosocial stress, Pardo explored whether prenatal neighborhood social cohesion was a protective factor for postpartum hypertension risk — a first investigation of its kind. This refers to the sense of connection and trust a pregnant woman experiences in her community. According to her findings, social structures that promoted cohesion may have had a positive influence throughout pregnancy into the postpartum period and were associated with lower blood pressure.

“We chose social cohesion as a variable to understand how connected the participants felt to their community. Right now, there aren’t many programs or policies that help foster cohesion, yet such interventions may serve as a novel protective factor,” she says.

According to Pardo, maternal health research has mostly focused on pregnancy outcomes, with limited studies investigating the mother’s health after birth. Yet, her results have shown how crucial this research is in identifying conditions rooted in pregnancy.

The real-world application of this study calls for the identification of vulnerable individuals in the pregnant population, offering interventions to reduce stress and depressive symptoms. Similarly, it emphasizes the importance of monitoring women’s health after birth, through the provision of additional hypertension screenings among mothers who experience higher prenatal stress.

“Pregnancy may be important in determining a woman’s long term cardiovascular health. Similarly, more research is needed to determine how different exposures during pregnancy can convey future cardiovascular risk to women,” she concludes.

A critical nutrient for life, most phosphorus in the soil is organic — from remains of plants, microbes or animals. But plants need inorganic phosphorus — the type found in fertilizers — for food. While researchers traditionally thought only enzymes from microbes and plants could convert organic phosphorus into the inorganic form, Northwestern scientists previously discovered iron oxides in natural soils and sediments can drive the conversion.

Now, in a new study, the same research team found iron oxides don’t generate just a negligible amount of the precious resource. In fact, iron oxides are incredibly efficient catalysts — capable of driving the conversion at rates comparable to the reactions of enzymes. The discovery could help researchers and industry experts better understand the phosphorus cycle and optimize its use, especially in agricultural soils.

The study was published today (March 4) in the journal Environmental Science & Technology.

“Phosphorus is essential to all forms of life,” said Northwestern’s Ludmilla Aristilde, who led the study. “The backbone of DNA contains phosphate. So, all life on Earth, including humans, depends on phosphorus to thrive. That’s why we need fertilizers to increase phosphorus in soils. Otherwise, the crops we need to feed our planet will not grow. There is a profound interest in understanding the fate of phosphorus in the environment.”

An expert in the dynamics of organics in environmental processes, Aristilde is an associate professor of environmental engineering at Northwestern’s McCormick School of Engineering. She also is a member of the Center for Synthetic Biology, International Institute for Nanotechnology and Paula M. Trienens Institute for Sustainability and Energy. Jade Basinski, a Ph.D. student in Aristilde’s laboratory, is the paper’s first author. Other Ph.D. students and postdoctoral researchers in Aristilde’s team contributed to the work.

Paths to accessing phosphorus

For centuries, farmers have added phosphorus to their fields to improve crop yields. Not only does it improve crop quality, phosphorus also promotes the formation of roots and seeds. Plants literally cannot survive without it.

But there’s a catch. Plants have evolved to use phosphorus in its simplest, most readily available form: inorganic phosphorus. Inorganic phosphorus is like a ready-to-use molecule that plants can easily consume and incorporate into their metabolism. Most phosphorus in the environment, however, is organic, meaning it’s bound to carbon atoms. To access this phosphorus, plants rely on their own secreted enzymes or enzymes secreted by microbes to break bonds in organic phosphorus and release the usable inorganic form.

In previous work, Aristilde’s team found that enzymes are not the only vehicles that can perform this essential conversion. Naturally occurring in soils and sediments, iron oxides, too, can perform the reaction that transforms organic phosphorus to generate the inorganic form.

How much and how fast?

After proving that iron oxides offer another pathway for plants to access phosphorus, Aristilde and her team sought to understand the rates and efficiency of this catalytic conversion.

“Iron oxides trap phosphorus because they have different charges,” Aristilde said. “Iron oxides are positively charged, and phosphorus is negatively charged. Because of this, anywhere you find phosphorus, you will find it linked with iron oxides. In our previous study, we showed iron oxides can serve as a catalyst to cleave the phosphorus. Next, we wanted to know how much they can cleave and how fast.”

To explore this question, the researchers investigated three common types of iron oxides: goethite, hematite and ferrihydrite. Using advanced analytical techniques, Aristilde and her team studied the interactions between these iron oxides and various structures of ribonucleotides, which are the building blocks of RNA and DNA. In their multiple experiments, Aristilde’s team looked for inorganic phosphorus both in the surrounding solution and on the surface of the iron oxides. By running experiments over a specific period of time and with different concentrations of ribonucleotides, the team determined the reaction’s rates and efficiency.

“We concluded that iron oxides are ‘catalytic traps’ because they catalyze the reaction to remove phosphate from organic compounds but trap the phosphate product on the mineral surface,” Aristilde said. “Enzymes don’t trap the product; they make everything available. We found goethite was the only mineral that didn’t trap all the phosphorus after the reaction.”

The team discovered that each type of iron oxide exhibited varying degrees of catalytic activity for cleaving phosphorus from the ribonucleotides. While goethite was more efficient with ribonucleotides containing three phosphorus, hematite was more efficient with ribonucleotides containing one phosphorus. Hematite is found in the midwestern part of United States, while goethite is commonly found in soils in the southern United States and South America.

What’s next

Next, Aristilde’s team will seek to understand why different iron oxides have different efficiency for the catalysis process and how goethite is able to release the phosphate but ferrihydrite and hematite trap all the produced phosphate. While the researchers initially hypothesized that the phosphorus compounds’ surface structure would play a role, they did not find a clear trend. Now, they think the chemistry of the mineral itself might be the secret behind its success.

Because phosphorus is a finite resource — mined from phosphate rock found only in the United States, Morocco and China — its supply is dwindling. Farmers and researchers worry phosphorus eventually will become so expensive that it will increase overall food costs, making basic staples unaffordable.

Finding new ways to convert trapped organic phosphorus into bioavailable inorganic phosphorus, therefore, is vital for the global food supply.

“Our work is providing a steppingstone for designing and engineering a synthetic catalyst as a way to recycle phosphorus,” Aristilde said. “We uncovered a reaction that’s happening naturally. The dream will be to leverage our findings as a way to make catalysts to contribute to the production of fertilizers for our food security.”

A team of researchers at Kyoto University recently set out to understand the mechanisms behind which two-hit stress contributes to brain dysfunction and mental disorders. They conducted a comprehensive investigation of the social and cognitive behaviors of mice that have been exposed to such stress, paying particular attention to anxiety-like behaviors.

Previously, this team demonstrated that acute inflammation in the cerebellum caused by a bacterial infection induces neural plasticity, which in turn may lead to hyper-excitability in the brain and the onset of depressive and autism-like symptoms. Yet exactly how two-hit stress contributes to changes in the brain had remained unclear.

Subject mice in the current investigation were allowed to freely explore, revealing extensive behavioral differences in two-hit mice, correlating with abnormalities in the cerebellum. In particular, the researchers observed a significant increase in the number and turnover of microglia, the primary immune cells found in the central nervous system. The study also revealed neuronal loss in the cerebellum, a reduction in the action potential firing of remaining cerebellar neurons, and a decrease in brain-wide functional connectivity.

“These results indicate cerebellar cognitive dysfunctions in animals exposed to two-hit stress,” says team member Momoka Hikosaka. The exposure to such stress altered the microglial reactivity in the cerebella of both male and female mice, leading to cerebellar dysfunction and behaviors resembling psychiatric disorders.

But it’s not all bad news. To rescue the exposed mice, the researchers used microglia replacement to ameliorate the effects of two-hit stress. Suppressing microglia can also be effective, but systemic depletion of microglia typically weakens immunity, making the body more susceptible to infections.

“To address this limitation, our team performed cerebellum-specific microglia replacement, which worked remarkably well,” says corresponding author Gen Ohtsuki, adding, “We were impressed to observe that the female mice showed notably higher stress resilience.”

This suggests that in some animals, sex differences in response to chronic inflammatory stress emerge in the cerebellum under certain conditions. Consequently, personalized medicine for mental health may require considering sex differences as an important factor, which could also be applied to neurodegenerative diseases and aging treatment.

Overall, these findings provide new pathways for understanding the biological mechanisms behind mental disorders, and have the potential to transform both scientific approaches and societal attitudes toward helping those affected.

Associate Professor Stephen Howie from the University’s Faculty of Medical and Health Sciences (FMHS) was an adviser to the Lancet Global Health Commission on Medical Oxygen Security and co-author of its report Reducing global inequities in medical oxygen access released 18 February.

A key finding shows global access to medical oxygen is highly inequitable. Five billion people, mostly from low and middle-income countries don’t have access to safe, quality, affordable medical oxygen.

Associate Professor Howie, child health researcher and a specialist paediatrician says he hopes further lives will be saved because of this work, and that children and adults will not only survive but thrive.

The Auckland University team are leading the field to improve access to medical oxygen. Howie recently gave a plenary address at the World Lung Health Conference in Bali, spelling out the challenges and opportunities to tackle the global issue.

“I have been working in the area of oxygen treatment for oxygen-starved (hypoxic) illnesses for two decades, particularly in Africa and the Pacific. My first priority was children (naturally, as a paediatrician) but we learnt soon enough that solving the problem has to involve catering for all ages.

“It is such an obvious need. I saw it at the hospitals I worked at in Africa where needless death from diseases like pneumonia happened because oxygen supplies were short, and this hit families and staff very hard. It was at that time that we made it our goal that ‘no child should die for lack of oxygen’ and this applies to adults too.”

Fiji was particularly hard hit when the first waves of the COVID-19 pandemic arrived, at one point it had the highest rate of COVID-19 in the world. A close partnership between the Fiji Ministry of Health, the University of Auckland, Cure Kids and Fiji National University, funded by New Zealand MFAT and other donors, played an important role in supporting the pandemic response says Howie.

A team of researchers from the School of Biological Sciences, The University of Hong Kong (HKU), addressed these questions in a recent paper in the Proceedings of the National Academy of Sciences (PNAS), USA, by compiling information on nearly 15,000 funded projects focused on species conservation. Professor Benoit GUÉNARD, the lead author of the study, noted that, “Our first conclusion is that funding for species conservation research remains extremely limited with only US$ 1.93 billion allocated over 25 years in the projects we assessed.”

The international conservation funding from 37 governments and NGOs represented a mere 0.3% and 0.01% of the annual budget of the NASA or US military, respectively. This stark comparison underscores the urgent need to dramatically increase such funding to slow global biodiversity loss.

The authors also examined the allocation of this funding to specific species or groups of organisms based on their conservation needs as assessed by the International Union for Conservation of Nature (IUCN) Red List, often called the ‘barometer of life’. Professor Guénard explains, “Based on previous literature-based studies, we expected biases towards vertebrates and, whilst this was true, we found the situation much worse than previously estimated. Even within vertebrates, many of the most threatened groups, like amphibians, were largely underfunded with declining funding trends over time.”

Another striking example can be found in reptiles, particularly lizards and snakes, where over a thousand species have been identified as threatened, yet 87% of the funding towards reptile conservation is directed towards the seven species of marine turtles. Professor Guénard states, “This highlights an important mismatch between scientific assessment of conservation and allocation of funding by conservation stakeholders, which appears to rely on the ‘charisma’ of species. This leads to nearly a third of the funding directed to non-threatened species while almost 94% of threatened species have not received any support.”

Some groups, like plants or insects, received a mere 6% each of the funding despite their vast diversity and the number of threatened species they include, while other major groups, such as fungi or algae, received virtually no funding.

Professor Alice HUGHES, a co-author of the study, echoed, “Our traditional view of what is threatened often does not align with species genuinely at threat, leaving many smaller, or ‘less charismatic’ species neglected. We urgently need to reframe this perspective and better allocate funding across taxa if we want any hope of redressing widespread population declines and the continued loss of biodiversity.”

Based on these findings, the researchers are calling for a new approach to conservation funding. Whilst species conservation is in dire need of additional funding, a more rigorous approach to selecting projects and species to receive those limited funds is urgently needed. Professor Guénard emphasises, “Conservation agencies and NGOs need to modify their philosophy towards conservation to protect all species, and not just a subset based on subjective criteria of charisma or beauty.”

In the future, the research team hopes their database can be expanded so information on funding allocation is more transparent and easily accessible. This would help evaluate existing gaps, plan effective future conservation efforts at a global scale, and reduce redundancy in funding for species that already receive the lion’s share of support.