Tech

WEST LAFAYETTE, Ind. -- Autonomous underwater vehicles have become versatile tools for exploring the seas. But they can be disruptive to the environment or have trouble traveling through confined spaces.

Purdue University researchers are studying an alternative: highly maneuverable, low-cost underwater gliders that operate silently. Components and sensors of the glider also can be easily swapped out or added according to a wide range of mission specifications.

"Our goal is persistent operation of mobile robots in challenging environments," said Nina Mahmoudian, associate professor of mechanical engineering. "Most underwater robots have limited battery life and must return back after just a few hours. For long-endurance operations, an underwater glider can travel for weeks or months between charges but could benefit from increased deployment opportunities in high-risk areas."

An underwater glider differs from other marine robots because it has no propeller or active propulsion system. It changes its own buoyancy to sink down and rise up, and to propel itself forward. Although this up-and-down approach enables very energy-efficient vehicles, it presents several problems: The vehicles are expensive, slow and not maneuverable, especially in shallow water.

Mahmoudian has developed an agile vehicle called ROUGHIE (Research Oriented Underwater Glider for Hands on Investigative Engineering). Shaped like a torpedo, ROUGHIE is about four feet long and features no outward propulsion or control surfaces other than a static rear wing. A video about the research is available on YouTube at https://youtu.be/_4wuvMjIsrI.

When deployed from shore or from a boat, ROUGHIE pumps water into its ballast tanks to change its buoyancy and provide initial glide path angle. To control its pitch, the vehicle's battery subtly shifts its weight forward and backward, acting as its own control mechanism. To steer, the entire suite of inner components are mounted on a rail that rotates, precisely controlling the vehicle's roll. The design is modular and adaptable for a variety of applications.

"This is a totally unique approach," Mahmoudian said. "Most underwater gliders can only operate in deep oceans and are not agile for confined spaces. ROUGHIE has a turning radius of only about 10 feet, compared to an approximately 33-foot turn radius of other gliders."

ROUGHIE is so maneuverable that Mahmoudian's team has been testing it in the diving well at Purdue's Morgan J. Burke Aquatic Center. By installing a motion capture system of infrared cameras below the water, they can track the vehicle's movements and characterize its maneuvering behavior in three dimensions with millimeter accuracy.

"We program ROUGHIE with flight patterns ahead of time, and it performs those patterns autonomously," Mahmoudian said. "It can do standard sawtooth up-and-down movements to travel in a straight line, but it can also travel in circular patterns or S-shaped patterns, which it would use when patrolling at sea. The fact that it can perform these tasks within the confined environment of a swimming pool using nothing but internal actuation is incredibly impressive."

This maneuverability means that ROUGHIE is able to follow complex paths and can explore real-world areas other underwater gliders can't.

"It can operate in shallow seas and coastal areas, which is so important for biology or climate studies," Mahmoudian said. "And because it's totally quiet, it won't disturb wildlife or disrupt water currents like motorized vehicles do."

ROUGHIE can be fitted with a variety of sensors, gathering temperature, pressure and conductivity data vital to oceanographers. Mahmoudian's team has sent ROUGHIE into small ponds and lakes with a fluorimeter to measure algae bloom. The team also outfitted the vehicle with compact magnetometers, capable of detecting anomalies like shipwrecks and underwater munitions. This research has been published recently in the journal Sensors.

Mahmoudian and her students have been developing ROUGHIE since 2012 when she began the project at Michigan Technological University.

"My students designed and built it from scratch, and they developed the control and navigational algorithms in parallel," Mahmoudian said. "For the price of a current commercial vehicle, we can put 10 of these in the water, monitoring conditions for months at a time. We believe this vehicle has great value to any local community."

Redirection of lymphocytes, via T-cell bispecific antibodies (TCBs) and chimeric antigen receptors (CARs), is already approved to treat some hematologic malignancies. In solid tumors these immune-based strategies continue to fail.

Research led by Joaquín Arribas, co-Program Director of Preclinical and Translational Research at VHIO, has now shown how HER2 breast cancer cells adopt a strategy to resist clearance by redirected lymphocytes. Findings evidence that the disruption of interferon-gamma signaling confers resistance to these immunotherapies and promotes disease progression.

These results, reported today in Nature Communications*, could help to potentiate future immune-based strategies and more precisely identify those patients who would be most likely to benefit from them.

Immunotherapy continues to show exciting promise in more effectively combating several tumor types. Many current strategies focus on ensuring the efficient delivery of active cytotoxic cells directly to tumors. It is thought that once the lymphocytes engage to cancer cells they will unfailingly destroy them, provided that inhibitory mechanisms are in check.

Results from a study published in Nature Communications*, now reveal how cancer cells escape death by lymphocytes through the disruption of interferon-gamma signaling. Co-first authored by Enrique J. Arenas and Alex Martínez-Sabadell, Post-doctoral Fellow and Graduate Student, respectively, of Joaquín Arribas' Growth Factors Group at VHIO, their findings show promise in potentiating future immune-based therapies against solid tumors.

Global research efforts centering on T cell-engaging therapies T-cell bispecific antibodies (TCBs) and chimeric antigen receptors (CARs), are heightening expectations for the more effective treatment of cancer.

"While these immune-based approaches have already been approved for the treatment of some hematologic malignancies, they fail to show efficacy in clinical studies with solid tumors. This failure has previously been associated with the incapacity of T-cells to successfully target cancer cells directly. Up until now, little has been reported on the mechanisms adopted by tumors which enable them to resist T-cell attack. This has been the focus of our present research," said Joaquín Arribas, co-Program Director of Preclinical and Translational Research at VHIO, ICREA Professor, CIBERONC Investigator, Director of the Hospital del Mar Medical Research Institute (IMIM), and Corresponding Author of this study.

He continued, "Several different strategies are now being implemented by the cancer research community to overcome these mechanisms of resistance. We aimed to go one step further by establishing whether more mechanisms exist that enable cancer cells to overcome the onslaught of targeted lymphocytes."

Using HER2-driven cell lines and PDXs, and a TCB and CAR targeting HER2, the investigators have now unmasked a novel mechanism of resistance to redirected T-cells. Specifically, they have discovered that even when active cytotoxic cells are successfully delivered to tumor cells, the latter adopt a strategy to avoid their elimination by lymphocytes. Findings suggest that the disruption of interferon-gamma signaling confers resistance and therefore promotes disease progression.

Interferon?gamma (IFN?γ) is a cytokine that assumes an important role in inducing and modulating an array of immune responses. "It acts as an interrupter that controls cell death. Certain cancer cells learn to switch off this pathway and thus survive the attack of lymphocytes. At present, there is no easy way of applying this discovery in clinical practice. Namely, to effectively identify those patients who have this pathway turned off. This represents a next step in our research; to develop a simple method to be able to do so," noted co-First Author, Enrique J. Arenas.

Previous research led by Joaquín Arribas published in Science Translational Medicine (2018) **, showed that the p95HER2-T-cell bispecific antibody can successfully guide lymphocytes directly to cancer cells for their targeted killing. This direct delivery was achieved thanks to the p95HER2 protein, which is only located in tumor cells. Representing a new therapeutic avenue and fresh hope for patients who have ceased to respond to current therapies, this novel immune-based approach can be used to tackle certain HER2+ breast cancers through its exclusive targeting of cancerous cells.

Building on these findings, the investigators hope to launch a new clinical trial in 2024-25 to further advance CAR-T targeting in breast cancer. "Driven by our discoveries, we aim to more precisely screen patients for enrollment in this clinical study, better predict when resistance will occur, and develop strategies to overcome the mechanisms that govern this resistance," concluded Joaquín Arribas.

This present research published today in Nature Communications also counted on the expertise and collaboration of investigators belonging to the VHIO-BBVA Foundation's Comprehensive Program of Cancer Immunotherapy & Immunology (CAIMI), and was supported through funding received from the Spanish Association against Cancer (Asociación Española contra el Cáncer - AECC), Breast Cancer Research Foundation (BCRF), and the Carlos III Health Institute (Instituto de Salud Carlos III - ISCIII).

In a new study led by Yale Cancer Center, researchers demonstrate sex hormones and insulin growth factors are associated with recurrence risk of endometrial cancer. The findings suggest endocrine-targeted therapies and an assessment of biomarkers in hormone and insulin signaling pathways may be useful in the prevention and treatment of endometrial cancer recurrence. The study is a collaboration with researchers at the University of Hawaii and The International Agency for Research on Cancer (IARC) and is published online today in the journal Cancer Epidemiology Biomarkers and Prevention.

"These findings are very encouraging," said Gloria Huang, MD, Associate Professor of Obstetrics, Gynecology & Reproductive Sciences at Yale School of Medicine, gynecologic oncologist at the Smilow Cancer Hospital Care Center in Greenwich, CT, and co-senior author of the study. "Women who are diagnosed with more advanced stages of endometrial cancer have a substantially higher risk of recurrence and death."

About 67,000 new cases of endometrial cancer are diagnosed every year in the United States. The disease starts when cells in the endometrium, the inner lining of the uterus, begin to grow out of control.

Researchers analyzed blood serum and endometrial tumor samples from several hundred women who participated in Gynecologic Oncology Group (GOG)-0210, a multi-institutional cooperative group study which prospectively followed women for up to 10 years following their initial surgical treatment for endometrial cancer. The focus was on women with the most common type of endometrial cancer, endometrioid adenocarcinoma, who were at risk for recurrence due to higher stage at presentation (Stages II to IV).

Study results showed a recurrence in 280 patients (34%) during a median of 4.6 years of follow-up. Estrogen-receptor positivity, insulin receptor positivity, and circulating insulin-like growth factor-I were inversely associated with recurrence risk.

Circulating estradiol hormone and positivity for phosphorylated IGF1R/IR (pIGF1R/pIR), the activated form of cellular receptors for insulin-like growth factors and insulin were associated with increased recurrence risk.

"Moving forward, we've begun a multi-center trial, which is currently open and enrolling patients at sites nationwide to evaluate the efficacy of a combination endocrine therapy for treating endometrial cancer recurrence," said Huang. "The therapy combines two oral medications to simultaneously block the endocrine pathways identified in this study. We hope that this research serves as the gateway to more effective and less toxic treatment options for women with advanced stage or recurrent endometrial cancer."

With a survival rate of only five years, the most common and aggressive form of primary brain tumor, glioblastoma multiforme, is notoriously hard to treat using current regimens that rely on surgery, radiation, chemotherapy and their combinations.

"Two of the major challenges in the treatment of gliomas include poor transport of chemotherapeutics across the blood brain barrier and undesired side effects of these therapeutics on healthy tissues," said Sheereen Majd, assistant professor of biomedical engineering at the University of Houston. "To get enough medicine across the blood brain barrier, a high dosage of medication is required, but that introduces more toxicity into the body and can cause more problems."

In an article published and featured on the cover of a January issue of Advanced Healthcare Materials, Majd reports a new glioma-targeted nano-therapeutic that will only address tumor cells offering increased effectiveness and reduced side effects.

An iron chelator known as Dp44mT (Di-2-pyridylketone-4,4-dimethyl-3-thiosemicarbazone) is an effective medication known to inhibit the progression of tumors but had not been used against brain tumors prior to this study. The chelator works to pull out the overabundance of iron needed by cancer cells, thus starving them.

Using clues from the tumors themselves, Majd developed a Dp44mT-loaded nano-carrier that would be drawn to glioma tumors, which present many IL13 (Interluken) receptors. Because the IL13 receptors are abundant, she added IL13 ligands onto her FDA-approved biodegradable polymer carrier (with the Dp44mT inside) so the receptors would lure the ligands, thus receiving the medicine.

Prior to her new carrier, the Dp44mT drug would be administered, but could go anywhere in the body, even places it is not meant to go.

"It's like an envelope with no address on it. It can land anywhere, and with toxins inside it could kill anything. Now, with our targeted delivery, we put an address on the package and it goes directly to the cancer cells," said Majd.

Aggressive brain tumors also develop high levels of multidrug resistance making them nearly impervious to common chemotherapeutics such as temozolomide or doxorubicin.
"There is, hence, an urgent need for more effective therapeutic formulations with the ability to overcome drug resistance in aggressive glioma tumors and to kill these malignant cells without damaging the healthy tissues," reports Majd.

Majd's study, which tested the nano-therapeutic both in vivo and in vitro, is the first report on targeted delivery of Dp44mT to malignant tumors.

Using the symmetries of the systems, people can define various topological invariants to describe different topological states. The topological materials can be accurately discovered by calculating the topological invariants. Recently, researchers found that irreducible representations and compatibility relationships can be used to determine whether a material is topological nontrivial/trivial insulator (satisfying the compatibility relations) or topological semimetal (violating the compatibility relations), which leads to a large number of topological materials predicted by theoretical calculations. However, Weyl semimetals go beyond this paradigm because the existence of Weyl fermions does not need any symmetry protections (except for lattice translation symmetries). At present, people usually take a very dense grid in the three dimensional Brillouin zone to search for Weyl fermions with zero band gap. Due to the large amount of computation required, this method is very inefficient. Therefore, it cannot be used to high-throughput search for Wey fermions. Considering the huge potential applications of Weyl semimetals, it is urgent to design a new algorithm or define a new topological invariant to search Weyl fermions accurately and quickly.

In a recent work published in Science Bulletin, Gao et al. proposed a new topological invariant χ in systems with S4 symmetry, which can be used to diagnose the existence of Weyl fermions effectively. χ is defined as the integral of Berry curvature on the orange plane (Surface S) in Fig. 1, and can be calculated simply by using the one dimensional Wilson-loop method. In addition, for magnetic systems, the nonzero χ can be revealed by the irreducible representations of occupied states on S4 invariant k-points. Thus it greatly reduces the calculation cost for searching for Weyl fermions. It is worth noting that this new invariant χ works for both magnetic and nonmagnetic systems.

By applying this method to high-throughput screening in the first-principles calculations, the authors predicted a lot of new magnetic and nonmagnetic Weyl semimetals. The experimental observations have shown that these newly discovered Weyl semimetals possess many unique properties, such as magnetoresistance, superconductivity, and spin glassy states etc. These materials provide realistic platforms for future experimental study of the interplay between Weyl fermions and other exotic states.

A new research study out of the University of Nevada, Reno's School of Community Health Sciences has just been published by the American Journal of Public Health and addresses state preemption of local sugar-sweetened beverage (SSB) taxes, issuing an emerging public health threat. Assistant Professor Eric Crosbie examines commercial determinants of health and public health policy, specifically in industries like tobacco and food and beverage.

"The beverage industry is aggressively attempting to preempt sugar-sweetened beverage taxes at the state level to prevent the diffusion of progressive policies at the local level throughout the United States," Crosbie, an affiliate of the University's Ozmen Institute for Global Studies, said. "Once preemption laws are enacted, they create a chilling effect that severely cripples local progress and are challenging to repeal."

Sugar-sweetened beverages, which include calorically sweetened sodas, energy and sports drinks, coffees, teas and fruit drinks, are the primary source of added sugars in the U.S. diet, increasing the risk of cardiometabolic diseases.

Between 2014 and 2017, excise taxes on SSBs were enacted by the Navajo Nation and seven U.S. cities (Albany, California; Berkeley, California; Boulder, Colorado; Oakland, California; Philadelphia, Pennsylvania; San Francisco, California; and Seattle, Washington). Washington D.C. enacted an SSB sales tax, but since 2017, political momentum has stalled due to beverage industry opposition.

Central to beverage industry opposition is the strategy of state preemption, which occurs when a higher level of government - like the state - limits the authority of lower levels - like municipalities - to enact laws.

Crosbie's research, supported by the University, shows that since 2017, Arizona, California, Michigan and Washington states have passed laws preempting local SSB tax policies, and in three of these states, it took an average of only 29 days from the policy's introduction to its passage: Arizona (46 days), California (5 days), and Michigan (37 days). Since 2017, four states - Illinois, New Mexico, Oregon and Pennsylvania - had policymakers withdraw preemption proposals or had them rejected by voters but only after strong opposition.

"The beverage industry has aggressively financed marketing campaigns, ballot initiatives and political representatives to secure preemption," Crosbie said. "Between 2016 and 2018, the beverage industry has spent at least $50 million on state preemption attempts in eight states."

While the beverage industry's use of state preemption to halt diffusion in local soda taxes is still in its early stages, the beverage industry uses time-tested strategies cultivated by the tobacco industry.

"Public health opposition to SSB tax preemption to date generally uses tactics that mirror those successfully pioneered by tobacco control advocates," Crosbie said. "Findings from this research point to the need for a robust national network of advocates, supported by national panels of legal experts, that can shift from a reactive to a proactive approach that halts the spread of preemption and begins the task of overturning existing statues."

Since 2000, state preemption limits local plastic bag laws, LGBTQ+ rights, minimum wage and local efforts to control the spread of COVID19 (e.g., through business closures).

Crosbie has both local and international experience collaborating with health organizations and health advocates to educate and disseminate academic research findings to policymakers, including publishing research in Spanish to reach wider audiences. Overall, his research is multi-disciplinary combining elements of public health, political science, international relations, economics, law and business to examine public health policy both locally and globally.

Learn more about an online Master of Public Health degree from the University of Nevada, Reno, helping graduates gain the knowledge needed to help benefit the public health community.

Isn't it convenient when office building windows adaptively darken according to the intensity of sunlight? Or when standard glasses turn into sunglasses under the sun and switch back as you enter a building? Such feats are possible thanks to photochromic materials, whose optical (and other) properties change radically when irradiated by visible or ultraviolet light.

Today, virtually all fast-switching photochromic materials are made using organic compounds. Unfortunately, this makes them considerably expensive and complex to synthesize, requiring multi-step processes that are difficult to scale up for mass production. So, despite the myriad of potential applications these materials could enable, their commercial application has been limited. Finding fast-switching inorganic photochromic materials, which could make those potential applications widely commercially possible, has proven challenging. However, a new study published in the Journal of the American Chemical Society brings new hope in this field.

In this study, a team of scientists from Ritsumeikan University, Japan, led by Associate Professor Yoichi Kobayashi, discovered that zinc sulfide (ZnS) nanocrystals doped with copper (Cu) ions have peculiar photochromic properties. When irradiated by ultraviolet and visible (UV-Vis) light, these crystals turn from creamy white to dark grey. What's especially interesting is that when the radiation source is turned off, it takes around a full minute for the material to revert to its original creamy white color in air, but it does so in the scale of microseconds when submerged in aqueous solutions. The team proceeded to theoretically and experimentally analyze this material, determined to clarify the intricacies of its never-seen-before photochromatic behavior.

But why do Cu-doped ZnS nanocrystals change color when irradiated by light, and why can it take long for them to return to their original color? The answer, as the scientists proved, has much to do with the dynamics of photoexcited charge carriers. When a photon hits a material, the collision can energize electrons and cause them to leave their otherwise stable positions in their molecular orbitals. The absence of the electron leaves a localized positive charge that, in solid-state physics, is referred to as a 'hole.'

In most materials, the electron-hole pair exists for a very short time before cancelling each other out, re-emitting a fraction of the energy that the electron originally obtained. However, in Cu-doped ZnS, the picture is very different. Holes are effectively trapped by Cu ions while photoexcited electrons can freely hop to other molecules, and these effects delay the recombination process. As the team demonstrated, the long-lived holes alter the optical properties of the material, causing the observed photochromatic effect.

The discovery of the first inorganic nanocrystal to exhibit fast-switching photochromism represents much needed progress in this field, especially for practical applications. "Zinc sulfide is relatively non-toxic and can be easily synthesized at low cost," comments Kobayashi. "We believe our research will lead to the widespread use of fast-response photochromic materials in society." Examples of notable applications for such photochromic materials include 3D television, smart glasses, windows for vehicles and houses, and even high-speed holographic storage. They could also be used as advanced anti-counterfeiting agents for important brands and medicines.

In addition, this study has implications for researchers who are willing to dig deeper into other areas of applied optical physics. In this regard, Kobayashi remarks: "We have demonstrated that the photochromic reaction of nanomaterials can be tuned by controlling the lifetime of photoexcited carriers. Exploring novel nanomaterials with ultralong-lived excited carriers is important not only for photochromic materials, but also for various advanced photofunctional materials, such as luminescent materials and photocatalysts."

Let us hope this study paves the way for photochromism to reach our daily lives and help make our futures (adaptively) brighter!

URBANA, Ill. ¬- In today's global economy, production of goods depends on inputs from many trade partners around the world. Companies and governments need a deeper understanding of the global value chain to reduce costs, maintain a profitable production system, and anticipate ripple effects of disruptions in the supply chain.

Applied economists from the University of Illinois have developed a new model for in-depth analysis of global supply chain linkages across countries and industries, providing a rich tool that delivers valuable insights for businesses and policy makers around the world.

"We live in a time when production processes are very much fragmented. In order to end up with one type of good, a car for example, many inputs are assembled abroad and imported from different places around the world. For instance, a car sold by leading U.S. companies may have anywhere from just 2% to 85% of U.S. and Canadian parts in it," says Sandy Dall'Erba, professor in the Department of Agricultural and Consumer Economics and director of the Regional Economics Applications Laboratory (REAL) at U of I. Dall'Erba is co-author of the study.

"Coordination of the entire supply chain system becomes more and more complicated and sensitive to disruptions at any stage throughout the process. If just one element in your supply chain is missing, it will have a ripple effect on the entire industry," Dall'Erba notes. "An example of this was the global semiconductor shortage that recently forced U.S. automakers to halt production."

The researchers started with a widely used economic growth model called shift-share decomposition and expanded its components to include interregional and inter-sectoral linkages. This allows them to identify, for each industrial sector and each country, if the growth of the sector of interest is due to supply chain linkages at the domestic level versus the international level. The latter can be further split between linkages with trade agreement partners (such as NAFTA for the U.S.) and countries from the rest of the world, highlighting the benefits of trade agreements.

"When we apply our technique to understand the drivers of growth in a particular sector, we not only can say whether it is growing faster or slower than another sector or region, we can also identify other sectors that are important for the growth of this particular sector," says Claudia Montania, the study's lead author. Montania was a visiting scholar in REAL when she conducted the study and is currently a researcher at the United Nations Development Accelerator Lab in Asuncion, Paraguay.

Traditional shift-share decomposition includes information about changes in the industry mix and in region-specific features such as taxes, regulations, or characteristics of the labor force. But it does not include connections among different regions or different industry sectors.

"The information provided by the traditional shift-share model is not enough," Dall'Erba notes. "For example, it would be a mistake to study only the food manufacturing sector in order to know what is happening in that sector, because it obviously depends on grain and livestock production which, in turn, depends on water and fertilizers among other inputs.

"In addition, grains are not always used for food manufacturing but they may end up as fuel. The supply chain of any sector is intertwined with that of many other sectors," he adds.

In the paper, Dall'Erba and Montania apply their model to country-sector linkages in the European Union, allowing them to compare three levels of connections - domestic, within the EU, and with the rest of the world, and to identify which ones matter most for each sector. The analysis included 35 industrial sectors in 15 countries from 1995 to 2006.

Overall, the researchers found the most important linkages were among EU trade partners; the second-most important were domestic ties; and the least important linkages were with the rest of the world. They emphasize the results vary across sectors and countries. For example, the supply-chain linkages in place to manufacture a French car are different from those that exist for a German car. Their multi-dynamic model can provide detailed, specific information for each country-sector combination as needed for preemptive and tailored planning and policy making.

"Knowing which type of linkages are the most important for your product or your sector can be very useful for local governments, for companies, and for producers, because you can make better plans to achieve the expected growth for your sector," Montania states. "You can also promote trade and diplomatic relationships in regions where you have strong sectoral linkages."

Dall'Erba points out this information can help countries and industries protect against supply chain disruptions. Those can occur in many forms, ranging from natural disasters such as drought or earthquake to political upheaval, trade wars, and even the global pandemic. For instance, the extreme disruption airline companies have experienced as demand for air travel dropped in 2020 means both Boeing and Airbus have significantly reduced their production and so have the multiple companies manufacturing airplane components from fuselage to seat belts.

"COVID-19 has pushed several governments to consider bringing back some industries in order to get better control over all the supply chain links. However, it is not necessarily a viable option as many companies have already de-located their unskilled labor-intensive production to low-wage countries while maintaining high-skilled workers at home," Dall'Erba concludes.

The development of low-energy-consumption and user-friendly electronic displays has become a long-term goal for future global sustainable development. Bistable electronic display, which requires very little electric drive to turn pages without consuming additional power to continuously display information/images, is one of the very good potential alternatives. Reflective display technologies with partial/complete bistable characteristics include e-ink, cholesteric liquid crystal, and electrochromic technologies, etc. They display information in light reflection mode, which can still be read under high-brightness outdoor sunlight and relatively dark indoor environments. It is also very friendly to the eyes, and can effectively avoid the damage to the eyes caused by the glare of traditional light-emitting display directly hitting the retina. In contrast, the bistable electrochromic materials and devices have attracted increasing attention all over the world due to their exciting advantages (such as, bright colors, wide color variation range and relatively easy preparation process, etc).

In a new paper published in Light Science & Application, a team of scientists, led by Professor Sean Xiao-An Zhang from State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, China, summarized new strategies to achieve more ideal bistable electrochromic systems.

Currently, various electrochromic materials have been exploited, and different bistable materials design and performance optimization strategies have been proposed, such as, the color and transmittance of the device can be changed through reversible deposition and dissolution of metal ions on the electrode surface to achieve bistable electrochromic display; the HOMO level of the redox polymer is regulated by modifying the substituent on the conjugate polymer's skeleton, thus affecting the interface charge transfer between the polymer and the electrode, and inhibiting the spontaneous redox reaction; the bistable performance of the material can be optimized by mixing different molecules together (such as, with the structural stability of the selenium-containing polymer and the good optical properties of the thiophene polymer in the visible region); exploit indirect EC system with a new mechanism---"regulatable electro-acid/base"-induced reversible molecular color switches. It is an effective way to overcome the insurmountable technical bottleneck of traditional direct EC systems by avoiding unstable free radicals during the reaction via collaborative interactions/stabilization, and has been widely used to overcome undesirable high-energy-state/-barriers of redox molecules for various chemical reactions.

Although the bistable displays technologies have shown super-power-saving performance. It has been long-expected to enter the market as a key technology and promote the "green and sustainable development" of global society. But they are currently competing mainly at the lower end of the market. The reason is that parts of their performance (such as the speed of turning pages and the color quality/brightness) are not yet comparable to the products of the mainstream light-emitting display. Therefore, there are two ways to enable the long-awaited green electronic displays to truly meet human needs for high-quality visual experience and low energy consumption, and make them popular in the mainstream market quickly. One of the solutions is to optimize the comprehensive performance of the bistable light-absorbing electronic display so that it can meet the actual requirements of high-end displays as soon as possible. However, as mentioned above, there are many very difficult technical obstacles in this path. First, the photodegradation and oxygen sensitivity of organic materials need to be overcome. We need to go beyond traditional thinking and technological frameworks to solve this problem. Regarding the protection of dye molecules from ultraviolet light, in addition to using traditional packaging materials to absorb and block light, we can explore whether ultraviolet light can be effectively converted into visible light by using small molecules or oligomers in the EC layer or packaging materials. That is, whether such energy conversion can further enhance the color brightness of EC displays. Secondly, strategies and materials for achieving more universal panchromatic tunability remain to be further developed. Thirdly, the in-depth study of electrochromic mechanism and dynamics of existing systems are not enough. For example, the synergies in PCET reactions, the dynamic processes of electrons and ions in inorganic/organic EC reactions, the electron transfer between the electrodes and the EC materials, and other processes involved in EC reactions all require further understanding and precise optimization. Fourth, the structure of the device needs further optimized, such as the construction of a conductive layer material with controllable ion transmission, the reference of electron/hole transmission material in OLED devices, the improvement of electron transmission between the active substance and the electrode via realization of nano-scale three-dimensional electrode. We should learn in depth from nature, explore the possibility of man-made "nerve networks" systems via structural design, synthesis and molecular self-assembly and attempt to use bionic "nerve networks" to replace the current method of electrolyte diffusion for quick transfer of electrons and charges in the system.

Another solution is to revolutionize the mainstream light-emitting displays by exploiting their bistable properties. To realize this seemingly "impossible" dream, it is obvious that revolutionary technologies will need to be combined with new display mechanism design and device structure optimization. We can also adopt strategies of cross-fusing mainstream and emerging display technologies with other existing technologies (such as electrofluorescence, electrophosphorescence, controllable delay (or long-lived) electroluminescence, and indirect EC molecular switching) to give more ideal performances for future display. Integrating a variety of known or new display technologies could provide a more promising strategy and product development to satisfy various human needs, such as EC-LED/OLED dual mode systems for all-weather ultra-power-saving display technology.

"History of human development shows that the driving force behind scientific and social progress is the spirit of questioning and challenging. Many seemingly "unsolvable" problems are gradually resolved by further understanding the cause of the problem through the collaboration of science and technology workers."

"Hopefully, this paper can allow an increasing number of researchers to understand the above scientific and technological challenges and their significance, trigger global cooperation to challenge the "impossible" scientifically forbidden zone and bring innovation in green technology to a new level." they added.

The yellow fever mosquito (Aedes aegypti) is a main vector of deadly diseases like dengue fever, chikungunya, and the Zika virus, which result in hundreds of thousands of deaths worldwide each year. Because Ae. aegypti prefers to bite humans and there are no vaccines for many of these diseases they carry, developing methods to control these insects is imperative in the fight to control illness.

In a study recently published in Proceedings of the National Academy of Sciences, a Yale-led research team developed a new method to track how Ae. aegypti move through the environment. By combining genetic data from the mosquitoes and environmental data from satellites, the authors mapped "landscape connectivity" -- defined as how a landscape facilitates the movements of organisms and their genes across large areas. In particular, the researchers developed a new workflow that more effectively models how Ae. aegypti are moving through the landscape in the southern U.S.

"Connectivity maps allow managers to make informed decisions based on how mosquitoes are likely to move through a landscape," says Evlyn Pless, a postdoctoral researcher at the University of California, Davis and a PhD graduate of Yale's Department of Ecology and Evolutionary Biology. "Our results suggest that in the southern U.S., Ae. aegypti travels by a mix of natural and human-aided dispersal, taking advantage of regions that are warmer and flatter, as well as human transportation networks."

Plessco-authored the paper with Giuseppe Amatulli, a research scientist with the Center for Research Computing and the Yale School of the Environment; Norah Saarman, assistant professor of biology at Utah State University; and Jeffrey Powell and Adalgisa Caccone from the Department of Ecology and Evolutionary Biology at Yale.

Now, the most common method for controlling invasive, disease-carrying species like Ae. aegypti is by using pesticides, which are not eco-friendly. "We now know some pesticides cause environmental harm, including harm to humans," says Saarman. "At the same time, mosquitoes are evolving resistance to the pesticides that we have found to be safe for the environment.

"This creates a challenge that can only be solved by more information on where mosquitoes live and how they get around."

One cutting-edge method of control is releasing genetically-modified mosquitoes into existing populations, in an effort to stunt reproduction and spread of the disease. The authors say they expect connectivity maps like those they've created to be useful in designing more strategic releases of modified mosquitoes.

"By integrating machine learning with an optimization process, our approach overcomes constraints of previous methods and should be helpful for more precise planning of vector control actions," says Amatulli.

The authors also believe this novel advance could have broader applications, including in conservation and environmental protection.

"Connectivity maps can also be essential for the protection of endangered native species,'' says Pless, "for example, in designing corridors to connect fragmented populations."

Integrated photonics was rejuvenated as Si starting challenging the dominant position of conventional III-V compound semiconductors at onset of the new millennium. Heterogeneous Si photonics utilizes wafer bonding to transfer functioning non-Si thin film onto Si substrate to make up missing or weak optoelectronic functionalities of Si material. In the past 15 years, it has evolved into a broad technology with many branches as shown in Fig. 1. As the most mature one among them, heterogeneous III-V-on-silicon integration provides an ideal platform to marry their respective material and production advantages. Two veteran researchers in this field, Dr. Di Liang from Hewlett Packard Labs and Prof. John Bowers from University of California - Santa Barbara, carefully reviewed a number of recent breakthroughs to show how this novel concept has evolved from a science project 15 years ago to a growing business and compelling research field today. It includes both commercial successes in large-volume optical transceiver product for data center interconnect application and new research directions in materials, device designs and integration platform innovations. Future development perspectives were discussed at the end to encourage more technological advances in academia and industry.

A recent study of homeless preschoolers found a strong correlation between the bonds those children formed with teachers and the children's risk of behavioral and emotional problems.

"It's well established that children who are homeless are at higher risk of a wide variety of negative outcomes," says Mary Haskett, corresponding author of the study and a professor of psychology at North Carolina State University. "However, there's a lot of variability within this group. We wanted to learn more about what makes some of these children more resilient than others."

For their study, researchers drew on survey and interview data from parents and teachers about 314 children participating in the Head Start preschool program.

The researchers found that 70% of the children were well adjusted and exhibited healthy behaviors, such as playing well with other kids. The remaining 30% struggled with behavioral and emotional challenges to varying degrees.

The study found that a high-quality child-teacher relationship was the variable that best predicted whether a child was in the healthy, low-risk group.

"The emotional bond or connection between teacher and child, and the lack of conflict in that relationship, was closely associated with the child being resilient," Haskett says. "This was an observational study, so we cannot say that the teacher-child relationship causes the resilience. But there is ample evidence that these relationships are important for all students, and this work suggests that it may be particularly important for housing insecure children."

"This finding has practical implications in the real world," says Kate Norwalk, co-author of the study and an assistant professor of psychology at NC State. "It highlights the importance of giving teachers - particularly teachers working with at-risk kids - the support they need in order to allow them to form these warm bonds with children."

"We would also love to do more work to determine if this is a causal relationship, meaning that the teacher-child relationship is what contributes to emotional resilience," Haskett says. "If so, more research could also help us determine how effective different interventions are at establishing and strengthening that bond."

A new study from researchers at the University of Ottawa's School of Psychology has found that using negative emojis in text messages produces a negative perception of the sender regardless of their true intent.

Isabelle Boutet, a Full Professor in Psychology in the Faculty of Social Sciences, and her team's findings are included in the study 'Emojis influence emotional communication, social attributions, and information processing' which was published in Computers in Human Behavior.

Study background: Eye movements of 38 University of Ottawa volunteer undergraduate student participants were tracked and studied, and the volunteers were shown sentence-emoji pairing under 12 different conditions where sentences could be negative, positive, or neutral, accompanied by a negative emoji, positive emoji, neutral emoji, or no emoji. With an average age of 18, participants were asked to rate each message in terms of emotional state of the sender and how warm they found them to be.

Dr. Boutet, whose research aims at understanding how humans analyze social cues conveyed by faces, discusses the findings.

What did you discover?

"Emojis are consequential and have an impact on the interpretation of the sender by the receiver and if you display any form of negativity - even pairing a positive emoji with a negative message - it is going to be interpreted negatively. You are going to be perceived as a person who is cold, and you will come across as in a negative mood when using negative emojis, regardless of the tone.

"Even if you have a positive message with a negative emoji, the receiver will interpret the sender as being in a negative mood. Any reference to negativity will drive how people interpret your emotional state when you write a text message.

"We also found certain types of messages were more difficult to convey; people have a lot of problems interpreting messages that are meant to convey irony or sarcasm."

What does this tell us about texting vs. face-to-face interactions?

"People often try to control the emotion they convey with their faces to avoid social conflict. Yet people use emojis for fun without giving it much thought when, in fact, they have a strong impact on interpersonal interactions.

"The big question is do emojis act as proxies, do they engage the same mechanism as facial expressions of emotions that play a large role in face-to-face (FTF) interaction? With FTF interactions, we have - through evolution - developed very evolved mechanisms that process these facial expressions of emotions. Kids use a lot of these digital interactions and they risk losing the ability to interact FTF."

How can the use of emojis and their meaning be improved?

"There are a lot of emojis and many we don't even know what they mean, and people can easily misinterpret them. We are looking at developing new emojis that convey emotions in more consistent and accurate manner, that better mimic facial expressions of emotions and reduce the lexicon of emojis, which could be especially helpful to less tech-savvy older adults. Our goals are to develop new emojis and/or memojis that convey clear signals that are not as confusing."

Any final thoughts?

"You should not think that emojis are a cute little thing that you add in a text message and that it has no consequence on your interaction. Emojis have large consequence and strong impact on how your text message will be interpreted and how you will be perceived."

Polished glass has been at the center of imaging systems for centuries. Their precise curvature enables lenses to focus light and produce sharp images, whether the object in view is a single cell, the page of a book, or a far-off galaxy.

Changing focus to see clearly at all these scales typically requires physically moving a lens, by tilting, sliding, or otherwise shifting the lens, usually with the help of mechanical parts that add to the bulk of microscopes and telescopes.

Now MIT engineers have fabricated a tunable "metalens" that can focus on objects at multiple depths, without changes to its physical position or shape. The lens is made not of solid glass but of a transparent "phase-changing" material that, after heating, can rearrange its atomic structure and thereby change the way the material interacts with light.

The researchers etched the material's surface with tiny, precisely patterned structures that work together as a "metasurface" to refract or reflect light in unique ways. As the material's property changes, the optical function of the metasurface varies accordingly. In this case, when the material is at room temperature, the metasurface focuses light to generate a sharp image of an object at a certain distance away. After the material is heated, its atomic structure changes, and in response, the metasurface redirects light to focus on a more distant object.

In this way, the new active "metalens" can tune its focus without the need for bulky mechanical elements. The novel design, which currently images within the infrared band, may enable more nimble optical devices, such as miniature heat scopes for drones, ultracompact thermal cameras for cellphones, and low-profile night-vision goggles.

"Our result shows that our ultrathin tunable lens, without moving parts, can achieve aberration-free imaging of overlapping objects positioned at different depths, rivaling traditional, bulky optical systems," says Tian Gu, a research scientist in MIT's Materials Research Laboratory.

Gu and his colleagues have published their results today in the journal Nature Communications. His co-authors include Juejun Hu, Mikhail Shalaginov, Yifei Zhang, Fan Yang, Peter Su, Carlos Rios, Qingyang Du, and Anuradha Agarwal at MIT; Vladimir Liberman, Jeffrey Chou, and Christopher Roberts of MIT Lincoln Laboratory; and collaborators at the University of Massachusetts at Lowell, the University of Central Florida, and Lockheed Martin Corporation.

A material tweak

The new lens is made of a phase-changing material that the team fabricated by tweaking a material commonly used in rewritable CDs and DVDs. Called GST, it comprises germanium, antimony, and tellurium, and its internal structure changes when heated with laser pulses. This allows the material to switch between transparent and opaque states -- the mechanism that enables data stored in CDs to be written, wiped away, and rewritten.

Earlier this year, the researchers reported adding another element, selenium, to GST to make a new phase-changing material: GSST. When they heated the new material, its atomic structure shifted from an amorphous, random tangle of atoms to a more ordered, crystalline structure. This phase shift also changed the way infrared light traveled through the material, affecting refracting power but with minimal impact on transparency.

The team wondered whether GSST's switching ability could be tailored to direct and focus light at specific points depending on its phase. The material then could serve as an active lens, without the need for mechanical parts to shift its focus.

"In general when one makes an optical device, it's very challenging to tune its characteristics postfabrication," Shalaginov says. "That's why having this kind of platform is like a holy grail for optical engineers, that allows [the metalens] to switch focus efficiently and over a large range."

In the hot seat

In conventional lenses, glass is precisely curved so that incoming light beam refracts off the lens at various angles, converging at a point a certain distance away, known as the lens' focal length. The lenses can then produce a sharp image of any objects at that particular distance. To image objects at a different depth, the lens must physically be moved.

Rather than relying on a material's fixed curvature to direct light, the researchers looked to modify GSST-based metalens in a way that the focal length changes with the material's phase.

In their new study, they fabricated a 1-micron-thick layer of GSST and created a "metasurface" by etching the GSST layer into microscopic structures of various shapes that refract light in different ways.

"It's a sophisticated process to build the metasurface that switches between different functionalities, and requires judicious engineering of what kind of shapes and patterns to use," Gu says. "By knowing how the material will behave, we can design a specific pattern which will focus at one point in the amorphous state, and change to another point in the crystalline phase."

They tested the new metalens by placing it on a stage and illuminating it with a laser beam tuned to the infrared band of light. At certain distances in front of the lens, they placed transparent objects composed of double-sided patterns of horizontal and vertical bars, known as resolution charts, that are typically used to test optical systems.

The lens, in its initial, amorphous state, produced a sharp image of the first pattern. The team then heated the lens to transform the material to a crystalline phase. After the transition, and with the heating source removed, the lens produced an equally sharp image, this time of the second, farther set of bars.

"We demonstrate imaging at two different depths, without any mechanical movement," Shalaginov says.

The experiments show that a metalens can actively change focus without any mechanical motions. The researchers say that a metalens could be potentially fabricated with integrated microheaters to quickly heat the material with short millisecond pulses. By varying the heating conditions, they can also tune to other material's intermediate states, enabling continuous focal tuning.

"It's like cooking a steak -- one starts from a raw steak, and can go up to well done, or could do medium rare, and anything else in between," Shalaginov says. "In the future this unique platform will allow us to arbitrarily control the focal length of the metalens."

Abu Dhabi, UAE, February 22: By engineering common filter papers, similar to coffee filters, a team of NYU Abu Dhabi researchers have created high throughput arrays of miniaturized 3D tumor models to replicate key aspects of tumor physiology, which are absent in traditional drug testing platforms. With the new paper-based technology, the formed tumor models can be safely cryopreserved and stored for prolonged periods for on-demand drug testing use. These cryopreservable tumor models could provide the pharmaceutical industry with an easy and low cost method for investigating the outcomes of drug efficacy, potentially bolstering personalized medicine. The developed technology can be transferred to other trending therapeutic applications such as measuring tumor response to drug concentration gradients, studying cancer cell signaling pathways, and investigations of invasive tumors.

The findings were published in the paper Cryopreservable Arrays of Paper-Based 3D Tumor Models for High Throughput Drug Screening, in the flagship journal, Lab on a Chip. The findings build on the team's earlier research engineering the paper platforms.

Led by Assistant Professor of Mechanical and Biomedical Engineering at NYUAD Mohammad A. Qasaimeh, the researchers sought to develop 3D tumor models because they offer great potential for understanding the fundamental mechanisms governing tumor responses to drug treatments, and provide opportunities to develop a number of emerging therapeutic applications. Currently, most pre-clinical drug screening is conducted on simplified two-dimensional (2D) monolayers of cell culture which do not fully represent the complexity of human tissues and organs.

Existing methods for developing 3D cell cultures and tumor models are laborious, technically challenging, time consuming, and do not allow cryopreservation for future use. This contributes to high attrition rates in the drug development process, and can cause significant delays to market and major financial losses to companies.

"Our work presents a paper patterning method for high throughput cell culture, cryopreservation, and drug testing of 3D tumor models. This technology is very promising to provide unparalleled advantages to the fields of drug discovery, tissue engineering, and personalized medicine," said Qasaimeh, the Principal Investigator of the Laboratory and the study leader.

By testing cisplatin (a typical chemotherapeutic drug) on breast cancer 3D models generated within the developed platform, they were able to prove that their technology is capable of predicting the outcomes of drug efficacy. Breast cancer is considered the most frequently diagnosed cancer in more than 80 percent worldwide. In the USA more than 10 percent of women are reported to develop invasive breast cancer over the course of their lives, and in the UAE, breast cancer is considered the most common malignancy based on incidence and mortality.

"Our reliable, easy-to-prepare, and inexpensive method is for creating high throughput paper-based arrays of 3D tumor models that will bring us one step closer to biomimetic drug screening in the pre-clinical stages," said Bisan Samara, the first author and a former research assistant in Qasaimeh's lab.

This research is an advancement of the team's earlier work, Paper-based Cell Cryopreservation, published last year in the journal Advanced Biosystems, in which they established their new technique utilizing filter paper to cryopreserve human cells, offering scientists an efficient alternative to conventional, long-term cryopreservation methods.