It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Wednesday, August 28, 2024
Insights into spinel cobalt oxides may lead to efficient ammonia synthesis
Advanced Institute for Materials Research (AIMR), Tohoku University
Researchers have made a significant breakthrough in the development of catalysts for the electrochemical nitrate reduction reaction (eNO₃RR) to ammonia, a process that has broad implications for sustainable energy, agriculture, and industrial applications.
Ammonia, a critical component in global food production, also holds promise as a zero-carbon fuel due to its high energy density, clean combustion products, and established infrastructure for storage and transportation. However, the current method of producing ammonia, the Haber-Bosch process, is energy-intensive and accounts for about 1.8% of global CO₂ emissions.
In their recent study, the research team focused on spinel cobalt oxides (Co₃O₄), a promising class of catalysts for eNO₃RR due to their low cost, high activity, and selectivity. The team synthesized various Co₃O₄ nanostructures with different crystallographic facets - {100}, {111}, {110}, and {112} - to investigate how these facets influence the catalyst's performance in ammonia production. The study revealed that the {111} facet of Co₃O₄ exhibited superior performance, achieving an impressive ammonia Faradaic efficiency of 99.1% and a yield rate of 35.2 mg h−¹ cm−².
"Our findings show that the {111} facet of Co₃O₄ is effective in transforming nitrate to ammonia," said Dr. Heng Liu, the co-first author of the paper and a Specially Appointed Assistant Professor at the Advanced Institute for Materials Research (WPI-AIMR), Tohoku University. "This is due to the rapid formation of oxygen vacancies and Co(OH)₂ on this facet, which significantly enhances the catalyst's performance."
In addition, the researchers discovered that the catalyst went through a transformation process during the reaction, evolving from Co₃O₄ to a structure with oxygen vacancies, then to a Co₃O₄−x-Ov/Co(OH)₂ hybrid, and finally stabilizing as Co(OH)₂. This process was most pronounced on the {111} facet, contributing to its superior performance.
"The structural changes we observed are crucial for understanding the catalyst's activity," added Professor Hao Li, corresponding author of the paper and an associate professor at WPI-AIMR. "These insights will help us design more efficient catalysts by optimizing the exposed facets."
Ammonia's importance extends beyond agriculture, as it is a potential zero-carbon fuel and a key player in energy conversion and storage technologies. The eNO₃RR offers a sustainable alternative to the Haber-Bosch process, transforming nitrate waste into valuable ammonia while aiding environmental remediation.
"This research lays a solid foundation for the development of more efficient, sustainable catalysts," states Li. "As we move forward, our goal is to control the final phases of the catalyst's transformation to further enhance its activity, selectivity, and stability."
This breakthrough in understanding and optimizing Co₃O₄ catalysts could pave the way for cleaner and more sustainable industrial processes, contributing to the global efforts to achieve carbon neutrality by the 2050s.
About the World Premier International Research Center Initiative (WPI)
The WPI program was launched in 2007 by Japan's Ministry of Education, Culture, Sports, Science and Technology (MEXT) to foster globally visible research centers boasting the highest standards and outstanding research environments. Numbering more than a dozen and operating at institutions throughout the country, these centers are given a high degree of autonomy, allowing them to engage in innovative modes of management and research. The program is administered by the Japan Society for the Promotion of Science (JSPS).
Advanced Institute for Materials Research (AIMR) Tohoku University Establishing a World-Leading Research Center for Materials Science AIMR aims to contribute to society through its actions as a world-leading research center for materials science and push the boundaries of research frontiers. To this end, the institute gathers excellent researchers in the fields of physics, chemistry, materials science, engineering, and mathematics and provides a world-class research environment.
Structural characterization of Co₃O₄ nanostructure with different facets.
Theoretical calculations: 1D surface Pourbaix diagrams for Co₃O₄ (100), (110), and (112) surfaces, and reaction free energy diagrams for various intermediates on Co₃O₄ and Co(OH)₂ surfaces during eNO₃RR. Insets show charge density differences and N=O bond lengths.
Facet-Dependent Evolution of Active Components on Spinel Co3O4 for Electrochemical Ammonia Synthesis
Article Publication Date
6-Aug-2024
Quenching the intense heat of a fusion plasma may require a well-placed liquid metal evaporator
Researchers believe they have found the ideal spot for liquid lithium in tokamaks
DOE/Princeton Plasma Physics Laboratory
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This photo, taken by PPPL Associate Research Physicist Eric Emdee, is figuratively reminiscent of the lithium vapor cave proposed to protect the interior parts of a tokamak from excess heat coming off the plasma.
Credit: Image credit: Eric Emdee and Kiran Sudarsanan / PPPL
Inside the next generation of fusion vessels known as spherical tokamaks, scientists at the U.S. Department of Energy’s Princeton Plasma Physics Laboratory (PPPL) envisioned a hot region with flowing liquid metal that is reminiscent of a subterranean cave. Researchers say evaporating liquid metal could protect the inside of the tokamak from the intense heat of the plasma. It’s an idea that dates back several decades and is tied to one of the Lab’s strengths: working with liquid metals.
“PPPL’s expertise in using liquid metals, particularly liquid lithium, for enhanced fusion performance is helping refine ideas about how it can best be deployed inside a tokamak,” said Rajesh Maingi, PPPL’s head of tokamak experimental science and co-author of a new paper in Nuclear Fusion detailing the lithium vapor cave.
Recently, researchers have been running computer simulations to find the best place for a lithium vapor “cave” inside the fusion vessel. To achieve commercial fusion, every part of the doughnut-shaped tokamak needs to be precisely placed. The idea behind a lithium vapor cave is to keep the lithium in the boundary layer away from the hot, fusing core plasma but near the excess heat. An evaporator — a heated surface to boil off lithium atoms — sets the lithium vapor particles off on the ideal course to where the bulk of the excess heat tends to accumulate. The scientists considered three choices in terms of cave placement. The lithium vapor cave could be located at the bottom of the tokamak near the center stack, in an area known as the private flux region; it could be in the outer edge, which is known as the common flux region; or the lithium vapor could come from both regions.
Now, results from multiple computer simulations have determined the best location for the lithium vapor cave is near the bottom of the tokamak by the center stack. The new simulations reflect additional information: They are the first to consider collisions between neutral particles, which have neither a net positive or negative charge.
“The lithium evaporator really does not work unless it is placed in the private flux region,” said Eric Emdee, an associate research physicist at PPPL and lead author of the new paper. When the lithium is evaporated in the private flux region, the particles become positively charged ions in a region with a lot of excess heat, protecting the nearby walls. Once the lithium particles are ionized, they obey the same magnetic fields as the plasma, spreading and dissipating the heat so it strikes a larger area of the tokamak and reduces the risk of components melting.
The private flux region is also the ideal target for the evaporated lithium because it is separate from the core plasma, which needs to stay hot. “You don't want your core plasma to get dirty with lithium and cool, but you also want the lithium to do some heat mitigation before it leaves the cave,” he said.
Holding the lithium: box versus cave
The researchers originally thought the lithium would be best housed in a “metal box” with an opening at the top. The plasma would flow into the gap so the lithium could dissipate the heat of the plasma before reaching the metal walls. Now, the researchers say a cave — geometrically just the inner half of a box — full of lithium vapor would be simpler than a box. The difference is more than just semantics: It impacts where the lithium travels and how effectively it dissipates heat.
“For years, we thought we needed a full, four-sided box, but now we know we can make something much simpler,” said Emdee. Data from new simulations pointed them in a different direction when the research team realized they could contain the lithium just as well if they cut their box in half. “Now we call it the cave,” Emdee said.
In the cave configuration, the device would have walls on the top, bottom and side closest to the center of the tokamak. This optimizes the path for the evaporating lithium, setting it on a better course for capturing the most heat from the private flux region while minimizing the complexity of the device.
Considering a capillary porous system to draw up the lithium
Yet another approach proposed by PPPL scientists in the new paper could achieve the same heat-quenching effect without drastically modifying the tokamak’s wall shape. In this approach, liquid lithium flows quickly under a porous, plasma-facing wall. This wall would be located where the excess heat impacts the tokamak the most: at the divertor. The porous wall allows the lithium to penetrate the surface directly facing the plasma heating, so liquid lithium is delivered exactly where it is needed most: at the area of the highest heat intensity. This capillary porous system is explained in an earlier paper published in the journal Physics of Plasmas.
The lead author of that paper, PPPL Principal Engineering Analyst Andrei Khodak, said he prefers the idea of using a porous plasma-facing wall on its own, as tiles embedded in the tokamak. “The advantage of the porous plasma-facing wall is that you don’t need to change the shape of the confinement vessel. You can just change the tile,” Khodak said. Khodak was also a co-author on the new paper, along with former Lab Director Robert Goldston.
Having lithium evaporation on the divertor surface leads to strong coupling between the plasma edge and the plasma-facing component in terms of heat and mass transfer because the heating from plasma will lead to lithium evaporation, which will, in turn, change the plasma heat flux to the liquid lithium plasma-facing component. A new model, described in a paper by the same authors in IEEE Transactions on Plasma Science, accounts for this strong two-way coupling. PPPL scientists and engineers will continue to test and develop their ideas as part of their core mission of making fusion an important part of the power grid.
The DOE supported work on the new Nuclear Fusion paper under contract number DE-AC02-09CH11466. The Physics of Plasmas manuscript was based upon work supported by the DOE, Office of Science, Office of Fusion Energy Sciences and was authored by Princeton University under contract number DE-AC02–09CH11466.
PPPL is mastering the art of using plasma — the fourth state of matter — to solve some of the world's toughest science and technology challenges. Nestled on Princeton University’s Forrestal Campus in Plainsboro, New Jersey, our research ignites innovation in a range of applications including fusion energy, nanoscale fabrication, quantum materials and devices, and sustainability science. The University manages the Laboratory for the U.S. Department of Energy’s Office of Science, which is the nation’s single largest supporter of basic research in the physical sciences. Feel the heat at https://energy.gov/science and https://www.pppl.gov.
This diagram shows a section of the cave, which would loop around the bottom of the tokamak near the center stack. Liquid lithium would sit in the bottom of the cave before evaporating.
This diagram shows a section of the cave, which would loop around the bottom of the tokamak near the center stack. Liquid lithium would sit in the bottom of the cave before evaporating.
Optimization of lithium vapor box divertor evaporator location on NSTX-U using SOLPS-ITER
Marriage strongly associated with optimal health and well-being in men as they age
No association was found between marriage and optimal aging among women — though older women who were widowed or divorce fared worse than their never-married peers
University of Toronto
A new study that followed over 7,000 Canadians, middle-aged and older, for approximately three years found that married men or men who became married during the study period were twice as likely to age optimally compared to their never-married male peers.
Among women, those who had never married were twice as likely to age optimally compared to married respondents who became widowed or divorced during the study period. Married women did not differ significantly from never-married women with respect to optimal aging.
“Little is known about the relationship between marital trajectories in old age and successful aging. Our goal was to see whether different marital trajectories were associated with physical health and well-being, and whether these relationships varied for men and women,” says first author Mabel Ho, a recent doctoral graduate at the University of Toronto’s Factor-Inwentash Faculty of Social Work (FIFSW) and the Institute of Life Course and Aging.
The researchers defined optimal aging as freedom from any serious physical, cognitive, mental, or emotional conditions that prevent daily activities, as well as high levels of self-reported happiness, good physical health, and mental health. The sample for the current study was restricted to the 40% of participants who were deemed to be successfully aging at the start of the study.
“Previous studies have shown that marriage is associated with better health outcomes for both men and women, while men who were never married generally had the poorest health outcomes,” says David Burnes, Professor and Canada Research Chair at the University of Toronto’s Factor-Inwentash Faculty of Social Work. “It may be that married people encourage each other to adopt or maintain positive health behaviors such as quitting smoking or exercising regularly.”
Older adults who were not socially isolated were more likely to maintain optimal health in old age. Those who had regular contact with relatives, friends and neighbors were more likely to age optimally compared to older adults who were socially isolated.
“Being socially connected with others is important, especially in later life. Having regular contact with relatives, friends and neighbours can help older adults feel connected, reduce their sense of loneliness, and improve their overall well-being,” says Eleanor Pullenayegum, a Senior Scientist at The Hospital for Sick Children (SickKids) and professor at the University of Toronto.
The study also found that lifestyle factors such as maintaining a healthy body weight, being physically active, not having insomnia and not smoking were important in maintaining optimal health in later life.
“It is so important to maintain a healthy lifestyle, no matter how old we are. For example, it is never too late to quit smoking,” says senior author Esme Fuller-Thomson, Director of the Institute for Life Course & Aging and Professor at the University of Toronto’s Factor-Inwentash Faculty of Social Work. “In our study those who were former smokers were much more likely to be aging optimally than those who continued to smoke.”
“Our study underlines the importance of understanding sex-specific differences in aging so that we can better support older men and women to continue to thrive in later life,” concluded Ho. “Our findings can inform the development of programs and services to engage and support older adults, particularly those who were never married or experienced widowhood, separation, and divorce in later life.”
This study entitled “The association between trajectories of marital status and successful aging varies by sex: Findings from the Canadian Longitudinal Study on Aging (CLSA)” was published online this week in the journal International Social Work. It uses longitudinal data from the baseline wave (2011-2015) and the first follow-up wave (2015-2018) of data from the Canadian Longitudinal Study on Aging (CLSA) to examine factors associated with successful aging. The CLSA included 7,641 respondents aged 60 years or older at wave 2 and in excellent health during the baseline wave of data collection.
The association between trajectories of marital status and successful aging varies by sex: Findings from the Canadian Longitudinal Study on Aging (CLSA)
Article Publication Date
27-Aug-2024
The power of face time: Insights from zebra finch courtship
McGill study challenges beliefs about learning and development
McGill University
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McGill researchers split zebra finches into groups to see how early life experiences affect learning.
A new study on songbirds sheds light on the power of social interaction to facilitate learning, insights that potentially apply to human development.
McGill University researchers discovered that zebra finches deprived of early social experiences could still form strong bonds with a partner later in life. Once placed into cohabitation with a male, females that had never heard a mating song before could quickly develop a preference for his melody.
The findings, published in Proceedings of the Royal Society B: Biological Sciences, challenge the belief that early experiences alone are critical for learning song preference.
“Young humans become attuned to the language they hear most, making it difficult to learn a new language as an adult because some sounds are hard to distinguish. Similarly, female zebra finches need to hear their species' songs when they're young to perceive them correctly. However, our study shows that social interactions later in life can help make up for this missed experience,” said senior author Sarah Woolley, an Associate Professor in the Department of Biology.
A bird’s-eye view of zebra finch courtship
Zebra finches are small Australian songbirds that often partner for life. Males sing melodies to attract a mate, while females learn which tunes they prefer by listening to adults.
In their experiments, the McGill team captured this courtship ritual on video. They split the zebra finches into groups: birds raised by their mom without exposure to song, and birds raised by both parents. Each group was then either paired with a male or housed with a female and only overheard males singing nearby.
To test song preference, female finches were given the opportunity to pull on strings that triggered different songs from a speaker; it was understood that the more a female pulled a certain string, the stronger her fondness for that melody.
Notably, females only developed an affinity for their partner’s song when they lived together. In contrast, females who only overheard males did not form these bonds. This suggests quality time is crucial for forming strong bonds, the researchers said.
Direct social interaction is key
“Think of it as the difference between people chatting over the phone versus spending quality time together. Direct social interaction allows zebra finches to form deeper connections with their mates,” said lead author Erin Wall, a PhD graduate in the Integrated Program in Neuroscience. “Females that never see or interact with a male directly become familiar with his voice, but they don’t develop a preference for him. They only know his song in the context of him courting someone else,” said Wall.
Zebra finches are often studied because they are highly social creatures with complex communication behaviours, making them ideal for research on social interaction and learning. The team’s future research will use brain scans to delve into the neural changes associated with pair bonding.
In an increasingly online world, the researchers say these findings could open new avenues of research into the role of face-to-face interaction in learning and social bonds.
About McGill University
Founded in Montreal, Quebec, in 1821, McGill University is Canada’s top ranked medical doctoral university. McGill is consistently ranked as one of the top universities, both nationally and internationally. It is a world-renowned institution of higher learning with research activities spanning three campuses, 12 faculties, 14 professional schools, 300 programs of study and over 39,000 students, including more than 10,400 graduate students. McGill attracts students from over 150 countries around the world, its 12,000 international students making up 30% of the student body. Over half of McGill students claim a first language other than English, including approximately 20% of our students who say French is their mother tongue.
An illustration shows how zebra finches were divided into groups to study how early life experiences affect learning later in life.
Credit
Erin Wal
Journal
Proceedings of the Royal Society B Biological Sciences
All organisms — from fungi to mammals — have the capacity to evolve and adapt to their environments. But viruses are master shapeshifters with an ability to mutate greater than any other organism. As a result, they can evade treatments or acquire resistance to once-effective antiviral medications.
Working with herpes simplex virus (HSV), a new study led by Harvard Medical School researchers sheds light on one of the ways in which the virus becomes resistant to treatment, a problem that could be particularly challenging among people with compromised immune function, including those receiving immune-suppressive treatment and those born with immune deficiencies.
Using a sophisticated imaging technique called cryogenic electron microscopy (cryo-EM), the researchers found that how parts of a protein responsible for viral replication move into different positions can alter the virus’s susceptibility to medicines.
The findings, published Aug. 27 in Cell, answer long-standing questions about why certain viruses, but not others, are susceptible to antiviral medications and how viruses become impervious to drugs. The results could inform new approaches that impede viruses’ capacity to outpace effective therapies.
Counterintuitive results
Researchers have long known changes that occur on the parts of a virus where antiviral drugs bind to it can render it resistant to therapy. However, the HMS researchers found that, much to their surprise, this was often not the case with HSV.
Instead, the investigators discovered that protein mutations linked to drug resistance often arise far from the drug’s target location. These mutations involve alterations that change the movements of a viral protein, or enzyme, that allows the virus to replicate itself. This raises the possibility that using drugs to block or freeze the conformational changes of these viral proteins could be a successful strategy for overcoming drug resistance.
“Our findings show that we have to think beyond targeting the typical drug-binding sites,” said the study’s senior author, Jonathan Abraham, associate professor of microbiology in the Blavatnik Institute at HMS and infectious disease specialist at Brigham and Women’s Hospital. “This really helps us see drug resistance in a new light.”
The new findings propel the understanding of how alterations in the conformation of a viral protein — or changes in how the different parts within that protein move when it carries out its function — fuel drug resistance and may be relevant for understanding drug effectiveness and drug resistance in other viruses, the researchers noted.
HSV, estimated to affect billions of people worldwide, is most commonly known as the cause of cold sores and fever blisters, but it can also lead to serious eye infections, brain inflammation, and liver damage in people with compromised immunity. Additionally, HSV can be transmitted from mother to baby via the birth canal during delivery and cause life-threatening neonatal infections.
Clues on resistance rooted in structure and movement
A virus can’t replicate on its own. To do so, viruses must enter a host cell, where they unleash their replication tools — proteins called polymerases — to make copies of themselves.
The current study focused on one such protein — a viral DNA polymerase — crucial for HSV’s ability to reproduce and propagate itself. The ability to carry out its function is rooted in the DNA polymerase’s structure, often likened to a hand with three parts: the palm, the thumb, and the fingers, each carrying out critical functions.
Given their role in enabling replication, these polymerases are critical targets of antiviral drugs, which aim to stop the virus from reproducing itself and halt the spread of infection. The HSV polymerase is the target of acyclovir, the leading antiviral drug for treating HSV infection, and of foscarnet, a second-line drug used for drug-resistant infections. Both drugs work by targeting the viral polymerase but do so in different ways.
Scientists have long struggled to fully understand how alterations in the polymerase render the virus impervious to normal doses of antiviral drugs and, more broadly, why acyclovir and foscarnet are not always effective against the altered forms of the HSV polymerase.
“Over the years, the structures of many polymerases from various organisms have been determined, but we still don’t fully understand what makes some polymerases, but not others, susceptible to certain drugs,” Abraham said. “Our study reveals that how the different parts of the polymerases move, known as their conformational dynamics, is a critical component of their relative susceptibility to drugs.”
Proteins, including polymerases, are not rigid, motionless objects. Instead, they are flexible and dynamic.Composed of amino acids, they initiallyfold into a steady, three‐dimensional shape known as the native conformation — their baseline structure. But as a result of various bonding and dispersing forces, the different parts of proteins can move when they come into contact with other cellular components as well as through external influences, such as changes in pH or temperature. For example, the fingers of a polymerase protein can open and close, as would the fingers of a hand.
Conformational dynamics — the ability of different parts of a protein to move — allow them to efficiently administer many essential functions with a limited number of ingredients. A better understanding of polymerase conformational dynamics is the missing link between structures and functions, including whether a protein responds to a drug and whether it could become resistant to it down the road.
Unraveling the mystery
Many structural studies have captured DNA polymerases in various distinct conformations. However, a detailed understanding of the impact of polymerase conformational dynamics on drug resistance is lacking. To solve the puzzle, the researchers carried out a series of experiments, focusing on two common polymerase conformations — an open one and a closed one — to determine how each affects drug susceptibility.
First, using cryo-EM, they conducted structural analysis to get high-resolution visualizations of the atomic structures of HSV polymerase in multiple conformations, as well as when bound to the antiviral drugs acyclovir and foscarnet. The drug-bound structures revealed how the two drugs selectively bind polymerases that more readily adopt one conformation versus another. One of the drugs, foscarnet, works by trapping the fingers of the DNA polymerase so that they are stuck in a so-called closed configuration.
Further, structural analysis paired with computational simulations suggested that several mutations that are distant from the sites of drug binding confer antiviral resistance by altering the position of the polymerase fingers responsible for closing onto the drug to halt DNA replication.
The finding was an unexpected twist. Up until now, scientists have believed that polymerases closed partially only when they attached to DNA and closed fully only when they added a DNA building block, a deoxynucleotide. It turns out, however, that HSV polymerase can fully close just by being near DNA. This makes it easier for acyclovir and foscarnet to latch on and stop the polymerase from working, thus halting viral replication.
“I’ve worked on HSV polymerase and acyclovir resistance for 45 years. Back then I thought that resistance mutations would help us understand how the polymerase recognizes features of the natural molecules that the drugs mimic,” said study co-author Donald Coen, professor of biological chemistry and molecular pharmacology at HMS. “I’m delighted that this work shows that I was wrong and finally gives us at least one clear reason why HSV polymerase is selectively inhibited by the drug.”
Authorship, funding, disclosures
Additional authors included Sundaresh Shankar, Junhua Pan, Pan Yang, Yuemin Bian, Gábor Oroszlán, Zishuo Yu, Purba Mukherjee, David J. Filman, James M. Hogle, Mrinal Shekhar.
This work was supported by the National Institutes of Health (awards R21 AI141940 and R01 AI19838), with additional funding from a Centers for Integrated Solutions in Infectious Diseases grant.
Viral DNA polymerase structures reveal mechanisms of antiviral drug resistance
Article Publication Date
27-Aug-2024
It’s the most common STI you’ve never heard of. Will this newly developed drug provide the cure?
Tulane University
Researchers at Tulane University are leading a groundbreaking study to seek a more effective treatment for trichomoniasis, an infection that, despite being the most common curable sexually transmitted infection (STI) worldwide, continues to fly under the radar.
The five-year, multi-center study is funded by a $9.2 million National Institutes of Health grant and will compare the effectiveness of a recently approved medication, secnidazole, against the current standard treatment, metronidazole, using a 1,200-person cohort across Louisiana, Alabama and Florida. Despite decades of use as the primary trichomoniasis medication, treatment by metronidazole continues to have a 10% breakthrough rate.
“More than 10 percent of people who take the recommended treatment still have it. That is just unacceptable. We need better options” said Dr. Patty Kissinger, professor of epidemiology at Tulane School of Public Health and Tropical Medicine. “The problem is trichomoniasis is the most common treatable STI, but there are often no symptoms, and the CDC has not recommended screening among asymptomatic people, so the public doesn’t know about it.”
Trichomoniasis, which infects about 156 million people annually worldwide, is caused by trichomonas vaginalis, a parasite that thrives in the genital tract of both men and women and causes inflammation. Those infected have a 1.5 times higher susceptibility to HIV. For expecting mothers, it can cause pre-term birth and increase risk for perinatal morbidity. African American women are also four times more likely to have trichomoniasis.
“Trichomoniasis affects millions but remains a highly neglected STI,” Kissinger said. “We’re hoping this study leads to better treatment options and increased awareness that we hope will encourage more screening.”
Because of the lack of inclusion in STI screenings and scant symptoms, those infected can go years before realizing they have trichomoniasis.
This is the third in a series of studies funded by the NIH to refine treatment for trichomoniasis. This is the first study in the series to include men in its cohort and the first-ever study to compare the effectiveness of secnidazole with metronidazole.
Questions remain as to why metronidazole continues to have a high breakthrough rate. The prior NIH studies found that metronidazole is most effective when administered in multiple doses, but the breakthrough rate may be attributed to patients missing doses or having sex with partners before treatment is completed, creating a cycle of reinfection.
The secnidazole treatment would only require one dose, although some concerns remain about the cost of the medication, Kissinger said.
Trichomoniasis affects more than 3 million people in the United States and is particularly prevalent in the Deep South where the study is being conducted.
“We need better treatments for this STI,” Kissinger said. “If this is successful, we could control it and encourage more screening that could reduce perinatal morbidity and maybe even reduce the chances of some people getting HIV.”
Both species may contribute to disease recirculation among each other’s populations, and diseases that have already devastated bighorns could be present in aoudad with unknown effects
Texas A&M University
By Courtney Price, Texas A&M College of Veterinary Medicine and Biomedical Sciences
A team of researchers at the Texas A&M College of Veterinary Medicine and Biomedical Sciences (VMBS) has discovered that aoudad — an animal in the sheep and goat family — can catch and spread many of the same respiratory pathogens that can impact desert bighorn sheep, a native species in Texas that often shares its habitat with aoudad.
The new research, recently published in the journal PLOS ONE, will help wildlife conservationists better understand the complex relationship between these two species and promote the management of both species. The project was made possible thanks to funding from the Wild Sheep Foundation and support from the Texas Parks & Wildlife Department.
Aoudad (pronounced “AH-dad”) originated in North Africa and were introduced to Texas for hunting opportunities in the late 1950s. Some wildlife experts estimate that there could be as many as 40,000 living in the state.
“There isn’t much research about disease transmission between Texas aoudad and native species like bighorn sheep. This makes it difficult for wildlife experts to monitor diseases and preserve animal populations,” said Dr. Logan Thomas, an assistant professor at Kansas State University and former postdoctoral researcher under Dr. Walter Cook, a clinical associate professor in the VMBS’ Department of Veterinary Pathobiology.
“If we can measure the disease exposure in both species, we can start to understand how they might affect each other,” he said. “By analyzing samples from both kinds of animals, we were ultimately able to determine that they too can carry and transmit the same respiratory illnesses.”
It Takes Two
Both aoudad and bighorn sheep are important animals for Texas wildlife conservation and the state’s economy. In West Texas, both animals are hunted as game, and some landowners make a significant portion of their income by charging hunters a fee to hunt on their land.
“Aoudad, in particular, are economically valuable for hunting opportunities,” Thomas said. “Since they’re a non-native species, there are no season or bag limits, which is very attractive to hunters.”
While bighorn sheep are also a favorite game animal among hunters, they require intensive management in Texas to keep their population numbers sustainable.
The respiratory diseases, including pneumonia, that both species can share have already wreaked havoc on bighorn populations, raising concerns among experts about what these diseases could do to aoudad, in addition to worsening the situation for bighorns.
“When there are outbreaks of these diseases in bighorn sheep, we usually see two waves of population decline,” Thomas said. “There’s a decline in all age groups when the outbreak first happens. Then there’s another wave after the lambs are born — many of them don’t survive because they haven’t been exposed to the disease and therefore lack an immune response like the older bighorns have.”
Complicating the problem is that some adult bighorns will carry the disease for several years after the initial outbreak, which means that the population may never have a chance to recover its numbers.
“We’ve known about this cycle in bighorn sheep for a while now, but no one had studied whether the same thing could happen in aoudad or if the two species could spread these pathogens back and forth,” he said. “We don’t suspect that it will be a significant health problem for aoudad, but we aim to learn more as we continue our research.”
Keeping A Close Watch
Now that the researchers have confirmed that aoudad can carry the same respiratory pathogens as bighorn sheep, wildlife experts can start to monitor disease transmission within and between those populations.
“Based on previous reports about this family of diseases, it’s also possible that they could spread to mule deer, which would complicate things further,” Thomas said. “We’re very interested in studying that in the future as well as how these diseases affect aoudad populations, since they haven’t received as much research attention on this as native species.
“Ultimately, we want all of these animal populations to thrive within a well-managed balance in Texas,” Thomas said. “Disease monitoring is one way we can take steps to make that happen.”
Evaluating the transmission dynamics and host competency of aoudad (Ammotragus lervia) experimentally infected with Mycoplasma ovipneumoniae and leukotoxigenic Pasteurellaceae
