Team develops HydroBIM platform for design of hydropower hub buildings

Platform provides digital design, intelligent construction, and smart operation

Peer-Reviewed Publication

TSINGHUA UNIVERSITY PRESS

 

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ILLUSTRATION SHOWS THE HYDROBIM SUMMARY THAT INCLUDES “ONE PLATFORM, TWO METHODS, THREE STAGES, FOUR MAJOR ENGINEERING, FIVE IN ONE, AND SIX-PARTY HARMONY.”

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CREDIT: JOURNAL OF INTELLIGENT CONSTRUCTION, TSINGHUA UNIVERSITY PRESS

A research team has developed a platform based on building information modeling (BIM) technology for use in the design of hydropower hub buildings. The platform, called HydroBIM, combines BIM technology with geographic information systems, computer-aided engineering, internet of things, artificial intelligence, and other technologies. The HydroBIM platform provides a comprehensive approach to digital design, intelligent construction, and smart operation of hydropower engineering projects.

 

The work is published in the Journal of Intelligent Construction on July 31, 2023.

 

The BIM technology originated in the United States. Over time, it has come to be widely adopted in the water conservancy and hydropower engineering in China. Researchers have extensively studied BIM technology and the ways to be applied in the entire life cycle of water conservancy and hydropower engineering. This research has shown the significant potential in improving the efficiency and quality of engineering design, construction, and operation management in water conservancy and hydropower engineering. In recent years, researchers have explored integrating BIM across various stages of engineering, including the planning and design, construction, and operation management.

 

This research team proposes a BIM-based system architecture for digital design, intelligent construction, and intelligent operation. Their work also provides a BIM-based multi-professional forward collaborative design method and BIM-based engineering construction management model, along with a real-time safety analysis and evaluation technology system based on actual measured safety information and construction. The last piece of their work was the development of the comprehensive control platform called HydroBIM.

 

“The HydroBIM system architecture provides an integrated management and control scheme for hydropower engineering planning and design, engineering construction, and operation management. It enables the management and control of water conservancy and hydropower engineering throughout the entire life cycle under the integration of multi-system and multi-software,” says Lei Yan from PowerChina Kunming Engineering Corporation.

 

The HydroBIM series platform has been successfully implemented in over 20 water conservancy and hydropower engineering projects in China, Laos, and Indonesia. Some of these projects include the Nuozhadu Dam, Huangdeng Dam, Hongshiyan barrier lake, Dianzhong Water Diversion Project, and the Kluet-1 hydro power project. Using the HydroBIM platform, the efficiency of design and analysis for water conservancy and hydropower hub buildings has been improved by 1.5 to 2 times in terms of time, compared to conventional methods.

 

The team summarizes the HydroBIM system as “one platform, two methods, three stages, four major engineering, five in one, and six party harmony.” They explain that summary in this way. The one platform is an entire life cycle management and control platform of water conservancy and hydropower engineering with multi-system and multi-software integration. Their two methods include conventional analysis and cloud computing. The three stages include the planning and design stage, the engineering and construction stage, and the operation and management stage. The four major engineering parts include the hub project, the electromechanical project, the reservoir project, and the ecological project. The five-in-one elements include design quality, project quality, construction management, project safety, and comprehensive benefits. The last part is the six-party harmony. This includes government agencies, owner units, design units, construction control units, construction units, and manufacturing units.

 

The team built the HydroBIM system framework to cover the entire life cycle of water conservancy and hydropower engineering, allowing for complete and interdisciplinary collaborative digital design during the planning and design stage. The engineering construction management stage provides full information management and control of contracts, progress, quality, safety, and investment. In the operation management stage, the system provides integrated management of engineering safety evaluation, early warning, and emergency planning through monitoring data and consistent guidelines for positive and negative evaluations. The HydroBIM platform also allows for the integration of multi-dimensional BIM information throughout the entire engineering life cycle.

 

The team’s results show that the HydroBIM platform can significantly improve cooperation between participants, work efficiency, and information integration, while ensuring the quality and safety of the life cycle of hydropower engineering. Additionally, the potential of emerging technologies such as artificial intelligence, knowledge graphs, digital twins, virtual reality, blockchain, meta-universe, and others that could be explored in the further to continuously improve the working mode of the water conservancy industry and improve its efficiency. “Overall, the HydroBIM platform represents a promising approach to the digital transformation of hydropower engineering and has significant potential for future development and application,” said Yan.

 

The research team includes Zongliang Zhang from PowerChina Kunming Engineering Corp. Limited and Power Construction Corp. of China; Sherong Zhang and Chao Wang from Tianjin University; Zhiyong Zhao from PowerChina Kunming Engineering Corp. Limited, Yunnan Digital Water Engineering Technology Innovation Center, and Yunnan Engineering Research Center for Intelligent Construction of Water Resources and Hydropower Projects; Lei Yan from PowerChina Kunming Engineering Corp. Limited; and Han Liu from PowerChina Kunming Engineering Corp. Limited and Tianjin University.

 

The research is funded by the National Key R&D Program of China Project, Yunnan Province Science and Technology Innovation Talent Program Project, Yunnan Provincial Key R&D Program

Project.

 

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About Journal of Intelligent Construction

Journal of Intelligent Construction (JIC), sponsored by Tsinghua University and China National Committee on Large Dams, published by Tsinghua University Press, is an international peer-reviewed journal for publishing original research papers, case studies, reviews and comments regarding the use of novel technologies in all domains of civil engineering, e.g., hydraulic engineering, structural engineering, geotechnical engineering, transportation, construction management, etc. The journal focuses on the application of advanced theories, methodologies, and tools, such as machine learning, sensors, robotics, 5G, internet of things, artificial intelligence, building information modelling, computational methods etc., in all stages of the construction life cycle, which makes the process more intelligent and efficient. The journal also covers other essential areas of civil engineering, e.g., planning and design, operation and maintenance, disaster mitigation.

 

About SciOpen

SciOpen is a professional open access resource for discovery of scientific and technical content published by the Tsinghua University Press and its publishing partners, providing the scholarly publishing community with innovative technology and market-leading capabilities. SciOpen provides end-to-end services across manuscript submission, peer review, content hosting, analytics, and identity management and expert advice to ensure each journal’s development by offering a range of options across all functions as Journal Layout, Production Services, Editorial Services, Marketing and Promotions, Online Functionality, etc. By digitalizing the publishing process, SciOpen widens the reach, deepens the impact, and accelerates the exchange of ideas.

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JOURNAL

Journal of Intelligent Construction

DOI

10.26599/JIC.2023.9180014 

ARTICLE TITLE

HydroBIM—Digital design, intelligent construction, and smart operation

 

Polyoxometalates and ionic liquid enhance solid-state lithium-ion electrolyte performance

Peer-Reviewed Publication

TSINGHUA UNIVERSITY PRESS

 

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THE GREEN POLYOXOMETALATE-BASED LITHIUM SALT (LPM) IS SANDWICHED BETWEEN TWO LAYERS OF AN IONIC LIQUID (ORANGE) THAT PROMOTES THE DISSOCIATION OF LITHIUM IONS FROM LPM, INCREASING ION CONDUCTIVITY OF THE COMPOSITE SOLID ELECTROLYTE MEMBRANE.

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CREDIT: POLYOXOMETALATES, TSINGHUA UNIVERSITY PRESS

Polyoxometalates (POMs) containing charged lithium ions combined with ionic liquids, increase the ion conductivity of a solid-state electrolyte membrane.

 

Solid-state lithium-ion batteries depend on the movement of ions (charged atoms) in the solid, rather than liquid, state to either charge or discharge the battery.  These solid-state electrolytes are safer, more cost efficient and capable of higher energy densities than batteries that rely on liquid electrolyte solutions, but suffer from low ionic conductivity, or movement of ions, and poor thermal stability. A new composite solid electrolyte (CSE) membrane was synthesized using lithium salts and an ionic liquid to improve the dissociation, and therefore conductivity, of charged lithium atoms in a solid-state electrolyte battery.

 

Polyoxometalates (POMs) are clusters of metal and oxygen atoms with properties that are determined by the well-defined structure of the POM atom cluster.  Researchers from Northeast Normal University recently introduced a POM-based lithium salt, Li6P2Mo18O62 (LPM) into a solid-polymer electrolyte (SPE) made up of the polymer polyethylene oxide (PEO), an inexpensive and stable chain of many ethylene oxide subunits.  PEO suffers from low ionic conductivity, and the addition of LPM salt alters the properties of the polymer and enhances ion movement. The research team also incorporated an ionic liquid (IL) to free lithium ions from LPM, further improving the conductivity of the composite electrolyte material.

 

The team published their results in the journal Polyoxometalates on September 28, 2023.

 

“Solid-state electrolytes (SSEs) are considered… the most promising candidates for next-generation energy storage devices due to their excellent thermal and electrochemical stability. Although SPEs have excellent flexibility and viscosity, they are severely limited due to their low ionic conductivity, poor mechanical strength and low thermal stability at room temperature. In contrast, inorganic solid electrolytes (ISEs) like LPM... usually have high ionic conductivity. By incorporating ISEs like LPM into SPEs to form composite polymer electrolytes, we leverage their respective properties… to achieve optimized mechanical properties and improve their ionic conductivity,” said Hong-Ying Zang, senior author of the paper and professor in the Key Laboratory of Polyoxometalate and Reticular Material Chemistry at Northeast Normal University in Changchun, China.

 

“Currently, inorganic electrolyte fillers include nanoparticles… and ionic-conductive inorganics. As a class of metal-oxygen clusters, the application of polyoxometalates in solid-state batteries is hampered by the difficulty of moving lithium ions. In this paper, we promote the dissociation of lithium ions from polyoxometalates with ILs… to impart LPM and IL composites (LPM-IL) with good electrical conductivity,” said Zang.

The team characterized the ion conductivity and mobility of the composite membrane by measuring the AC impedance, or the resistance of current flow in a circuit.  The team found that electrolyte membranes containing the optimal concentration of LPM and IL demonstrated three times higher conductivity than membranes prepared without IL.

 

In a similar manner, the team determined that the conductivity of composite membranes generated with polyvinylidene fluoride (PVDF), a non-reactive thermoplastic filler material, in conjunction with PEO increased conductivity ten times compared to LPM-IL membranes synthesized without PVDF.  The composite membrane also demonstrated good stability over 12 hours at a temperature of 80℃. 

 

“The results of these experiments demonstrate that polyoxometalates can be used as inorganic solid electrolytes,” said Zang. IL effectively increased the dissociation of lithium ions from LPM and improved the ionic conductivity of the composite solid electrolyte membrane. The incorporation of PVDF also created a PEO-PVDF conductive network in the membrane that further promoted lithium ion movement, enhancing conductivity.

 

The research team believes their unique, PEO-based composite membrane containing PVDF, POM-based lithium salt and IL provides a practical means of increasing ionic conductivity in solid-state electrolytes for use in lithium-ion batteries.  “Our next step is to improve the performance of polyoxometalates to create better solid-state lithium-ion batteries,” said Zang.

 

Other contributors include Qianqian Liu, Yunzuo Cui, Lijie Zhu, Dongming Cheng, Chen Wang, Siqi Lu, Bo Li and Xinyu Chen from the Key Laboratory of Polyoxometalate and Reticular Material Chemistry at the Ministry of Education at Northeast Normal University in Changchun, China.

This work was supported by the National Natural Science Foundation of China (Grant No. 22302102, 21871042, 21471028, 22073094), the Fundamental Research Funds for the Central Universities-Excellent Youth Team Program (2412023YQ001), the Natural Science Foundation of Jilin Province (Grant No. 20200201083JC) and the Natural Science Foundation of Department of education of Jilin Province (JJKH20201169KJ).

 

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About Polyoxometalates  

Polyoxometalates is a peer-reviewed, international and interdisciplinary research journal that focuses on all aspects of polyoxometalates, featured in rapid review and fast publishing, sponsored by Tsinghua University and published by Tsinghua University Press. Submissions are solicited in all topical areas, ranging from basic aspects of the science of polyoxometalates to practical applications of such materials. Polyoxometalates offers readers an attractive mix of authoritative and comprehensive Reviews, original cutting-edge research in Communication and Full Paper formats, Comments, and Highlight.

 

About SciOpen

SciOpen is a professional open access resource for discovery of scientific and technical content published by the Tsinghua University Press and its publishing partners, providing the scholarly publishing community with innovative technology and market-leading capabilities. SciOpen provides end-to-end services across manuscript submission, peer review, content hosting, analytics, and identity management and expert advice to ensure each journal’s development by offering a range of options across all functions as Journal Layout, Production Services, Editorial Services, Marketing and Promotions, Online Functionality, etc. By digitalizing the publishing process, SciOpen widens the reach, deepens the impact, and accelerates the exchange of ideas.

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JOURNAL

Polyoxometalates

DOI

10.26599/POM.2023.9140036 

ARTICLE TITLE

Ionic liquid-mediated PEO-based solid-state electrolyte membrane modified with Dawson-type polyoxometalates

Stronger lithium batteries may need ‘weaker’ solvation structure, researchers report

Peer-Reviewed Publication

TSINGHUA UNIVERSITY PRESS

 

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EMERGING ELECTROLYTES WITH A DIFFERENT MICROSTRUCTURE TO CONVENTIONAL ELECTROLYTES MAY HELP ADVANCE LITHIUM BATTERIES TO KEEP PACE WITH FUTURE TECHNOLOGIES, ACCORDING TO A REVIEW PAPER FROM RESEARCHERS AT THE HONG KONG POLYTECHNIC UNIVERSITY. THEIR ANALYSIS CONCLUDED THAT BETTER KINETICS, REDUCED SOLVENT POLARIZATION, REDUCED DESOLVATION ENERGY AND MORE INORGANIC-RICH INTERPHASES MAY IMPROVE LITHIUM BATTERIES.

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CREDIT: ENERGY MATERIALS AND DEVICES, TSINGHUA UNIVERSITY

Lithium batteries power our phones, computers, many of our cars and so much more — even the drill and weedwhacker. But as technology advances, can they keep up in their current format? No, but there is a way forward, according to a new review paper from researchers at Hong Kong Polytechnic University, by further developing the electrolytes that allow for energy storage and discharge.

 

The team published their work in Energy Materials and Devices on September 18, 2023.

 

“Lithium batteries have revolutionized our modern life,” said first author Zhijie Wang, a Postdoctoral Research Fellow in the Department of Applied Physics and the Research Institute of Smart Energy at Hong Kong Polytechnic University. “The performance of lithium batteries — including energy density, lifespan, safety and more — is greatly determined by the recipe and microstructure of the electrolytes.”

 

Lithium batteries consist primarily of two current collectors, a negatively charged electrode, a positively charged electrode, an electrolyte and a separator. The electrolyte carries positively charged lithium ions from the positively charged electrode through the separator to the other electrode and negatively charged ions in the other direction. As the lithium ions move through the electrolyte, the anode collects free electrons, leading to a positive charge at one current collector. That positive current discharges to power a device, flowing through and returning to the battery as a negative current.

 

Electrolytes most commonly comprise a solution of lithium salt in a polar solvent, or a substance that uses a tiny electrical charge produced by the shape of its constituent molecules to dissolve the salts and free the lithium ions. In conventional electrolyte, lithium ions separate with the salt anions; in the (localized) high-concentration electrolytes developed in recent years, salt anions are solvated with Li ions, and they have unique functions in improving battery performance.

 

However, Wang said, a type called weakly solvating electrolytes first proposed for this use three years ago may offer a pathway to more robust batteries. In this type of electrolyte, the lithium ions are weakly coordinated with the solvent molecules, and they also coordinate with the negatively charged salt anions.

 

“Such a structure can be obtained in a relatively dilute salt concentration and without the use of non-solvating diluters,” Wang said. “This makes it different from conventional electrolytes and (localized) high-concentration electrolytes. It can improve the low-temperature, fast-charging, safety and cycling properties of lithium batteries, so it has attracted intensive research interest in recent years.”

 

In this study, Wang and corresponding author Biao Zhang examined recent research papers on weakly solvating electrolytes and concluded that basic design principles and future research directions were lacking. Zhang is an associate professor in the Department of Applied Physics and the Research Institute of Smart Energy at Hong Kong Polytechnic University.

 

“We found, from the current literature, that the key to constructing weakly solvating electrolytes is creating a balance between the interactions of lithium ions with solvent and anions,” Wang said. “We also determined that the design concepts of weakly solvating electrolytes can be extended to other batteries, such as systems made with sodium, potassium, magnesium or zinc.”

 

The researchers also recommended that future work in the field should focus on simplifying the synthesis procedures, improving yields and reducing costs of the electrolyte components.

 

“The goal of this paper is to promote the understanding of both research and industrial communities on the functions, design principles and recent research progress of the emerging weakly solvating electrolytes,” Wang said. “We hope our insights contribute to developing next-generation lithium batteries with robust properties and thus boost their share of the power source market, especially in electric vehicles.”

 

The Hong Kong Polytechnic University supported this work.

 

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About Energy Materials and Devices

Energy Materials and Devices is launched by Tsinghua University, published quarterly by Tsinghua University Press, aiming at being an international, single-blind peer-reviewed, open-access and interdisciplinary journal in the cutting-edge field of energy materials and devices. It focuses on the innovation research of the whole chain of basic research, technological innovation, achievement transformation and industrialization in the field of energy materials and devices, and publishes original, leading and forward-looking research results, including but not limited to the materials design, synthesis, integration, assembly and characterization of devices for energy storage and conversion etc.

 

About SciOpen

SciOpen is a professional open access resource for discovery of scientific and technical content published by the Tsinghua University Press and its publishing partners, providing the scholarly publishing community with innovative technology and market-leading capabilities. SciOpen provides end-to-end services across manuscript submission, peer review, content hosting, analytics, and identity management and expert advice to ensure each journal’s development by offering a range of options across all functions as Journal Layout, Production Services, Editorial Services, Marketing and Promotions, Online Functionality, etc. By digitalizing the publishing process, SciOpen widens the reach, deepens the impact, and accelerates the exchange of ideas.

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JOURNAL

Energy Materials and Devices

DOI

10.26599/EMD.2023.9370003 

ARTICLE TITLE

Weakly solvating electrolytes for next-generation lithium batteries: design principles and recent advances

 

Endemic malaria found in high, dry northwestern Kenya

Region was thought to be low-risk, but new mosquito and tougher parasite are changing that

Peer-Reviewed Publication

DUKE UNIVERSITY

 

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MAP SHOWS ENDEMIC AREAS OF PLASMODIUM VIVAX ACROSS AFRICA AND ACROSS KENYA (PANEL B). DATA FROM MALARIA ATLAS PROJECT. GRAPHIC FROM APPENDIX OF PAPER.

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CREDIT: “PLASMODIUM VIVAX PREVALENCE IN SEMIARID REGION OF NORTHERN KENYA, 2019,” WENDY PRUDHOMME-O’MEARA W, LINDA MARAGA, HANNAH MEREDITH, DANIEL ESIMIT, GILCHRIST LOKOEL, TABITHA CHEPKWONY, JOSEPH KIPKOECH, GEORGE AMBANI, DIANA MENYA, ELIZABETH FREEDMAN, STEVE TAYLOR, ANDREW OBALA. EMERGING INFECTIOUS DISEASES, NOV. 2023. DOI: 10.3201/EID2911.230299

DURHAM, N.C. -- Turkana County in northwestern Kenya was supposed to be the land that malaria forgot. An arid, windy region abutting Uganda, South Sudan and Ethiopia, its climate was thought to be too dry for the mosquitoes that harbor malaria-causing parasites, and thus it has been excluded from national efforts to prevent the spread of the disease.

But that assumption may have been wrong, according to a new study by malaria researchers at the Duke Global Health Institute and Moi University in Kenya. And worse, it may leave an opening for new forms of malaria that could reverse the progress East Africa has made in controlling the disease.

“These findings are game-changers for malaria control in East Africa,” says Wendy Prudhomme O’Meara, Ph.D., a professor of medicine and global health at Duke who led the research.

O’Meara’s team found that approximately 30 percent of the people they tested in Turkana County had malaria parasites in their blood, indicating that the disease was already endemic in the region. But even more concerning was the type of malaria: Researchers found a small but significant incidence of a parasite called Plasmodium vivax, which historically has been almost non-existent in sub-Saharan Africa. The study is the first to confirm cases of P. vivax malaria in Kenya that were likely the result of local transmission.

The parasite’s appearance in Kenya may be connected to an invasive mosquito species known as Anopheles stephensi, which migrated to the Horn of Africa during the past decade and has been found in five countries in northern Africa. Its arrival in Djibouti in 2016 coincided with a 100-fold increase in malaria cases, leading the World Health Organization to issue an alert about the insect’s invasion, calling it “a major potential threat to malaria control and elimination” on the continent.

“If we don’t do something about it, we’re going to be in trouble very soon,” says Eric Ochomo, Ph.D., a medical entomologist with the Kenya Medical Research Institute who identified the invasive species in northern Kenya in December 2022, around the same time as O’Meara’s study.

Both the mosquito and the parasite it carries present significant challenges to the continent’s malaria control efforts, the researchers warn. P. vivax behaves differently than the most prevalent forms of malaria in Africa, which can allow it to evade screening tests and therapies most frequently used across the continent. It can go dormant in the liver, causing relapses weeks or months after infection.

“We are worried that with the presence of the An. stephensi, cases of  P. vivax malaria may very well increase,” says O’Meara, who has been working on malaria prevention in Kenya since 2003. “There are no measures in place for P. vivax malaria control in Kenya, and it needs some targeted mechanisms.”

Native to India, Anopheles stephensi mosquitoes thrive around sewers and dirty water, making them more adaptable to urban areas. The fact that they are breeding successfully in hot, dry regions like Turkana should cause public health officials to rethink their assumptions about malarial hot spots, Ochomo says.

“Areas that are either approaching elimination or that are categorized as low risk are going to end up with higher prevalence than they currently see,” he says.

O’Meara’s team shared their findings with Kenya’s National Malaria Control Program, which is now ramping up distribution of mosquito nets and surveillance in Turkana County. The researchers also plan to work with community members to identify and eliminate potential mosquito breeding grounds.

A spike in P. vivax cases could also undermine what was thought to be a genetic firewall against the parasite spreading on the continent. Many Africans have a genetic trait that is believed to protect against P. vivax infection, which is one reason cases have been relatively rare. But O’Meara says there are signs that recent outbreaks may be affecting even those with the genetic protection, a reminder that the parasite is constantly evolving new ways to evade defenses. 

“The malaria parasite has successfully transmitted between humans and mosquitoes for tens of thousands of years,” she says. “The co-evolution of the parasite with humans has made it incredibly difficult to eliminate.”

CITATION:  “Plasmodium vivax Prevalence in Semiarid Region of Northern Kenya, 2019,” Wendy Prudhomme-O’Meara W, Linda Maraga, Hannah Meredith, Daniel Esimit, Gilchrist Lokoel, Tabitha Chepkwony, Joseph Kipkoech, George Ambani, Diana  Menya, Elizabeth Freedman, Steve Taylor, Andrew Obala. Emerging Infectious Diseases, Nov. 2023. DOI: 10.3201/eid2911.230299

Online: https://wwwnc.cdc.gov/eid/article/29/11/23-0299_article

A traditional method of gathering clean water in Northwestern Kenya involves making pits on the sandy riverbank and letting the water filter upward into the hole. People then painstakingly scoop up this relatively clean water for use, but the pits left behind make excellent mosquito breeding habitat.

Kenyan community health workers being trained on malaria inspect mosquito larvae scooped from an irrigation canal.

CREDIT

Wendy Prudhomme O’Meara - Duke Global Health

JOURNAL

Emerging Infectious Diseases

DOI

10.3201/eid2911.230299 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Plasmodium vivax Prevalence in Semiarid Region of Northern Kenya, 2019

ARTICLE PUBLICATION DATE

10-Oct-2023

 

Traumatic memories can rewire the brain

Researchers from the National Institute for Physiological Sciences find neural correlates of fear-based learning in mice

Peer-Reviewed Publication

NATIONAL INSTITUTES OF NATURAL SCIENCES

 

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DETECTING LEARNING-DEPENDENT CHANGES IN NEURAL NETWORKS TO UNDERSTAND HOW MEMORY IS MADE IN THE PREFRONTAL REGION OF THE BRAIN

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CREDIT: MASAKAZU AGETSUMA OF NATIONAL INSTITUTE FOR PHYSIOLOGICAL SCIENCES；ILLUSTRATION OF MOUSE FROM CANSTOCKPHOTO.

Okazaki, Japan – Scientists have long speculated about the physical changes that occur in the brain when a new memory is formed. Now, research from the National Institute for Physiological Sciences (NIPS) has shed light on this intriguing neurological mystery.

In a study recently published in Nature Communications, The research team has succeeded in detecting the brain neuronal networks involved in trauma memory by using a novel method that combines optical and machine-learning-based approaches, capturing the complex changes that occur during memory formation and uncovering the mechanisms by which trauma memories are created.

Animals learn to adapt to changing environments for survival. Associative learning, which includes classical conditioning, is one of the simplest types of learning and has been studied intensively over the past century. During the last two decades, technical developments in molecular, genetic, and optogenetic methods have made it possible to identify brain regions and specific populations of neurons that control the formation and retrieval of new associative memories. For instance, the dorsal part of the medial prefrontal cortex (dmPFC) is critical for the retrieval of associative fear memory in rodents. However, the way in which the neurons in this region encode and retrieve associative memory is not well understood, which the research team aimed to address.

“The dmPFC shows specific neural activation and synchrony during fear-memory retrieval and evoked fear responses, such as freezing and heart rate deceleration,” explains lead author Masakazu Agetsuma. “Artificial silencing of the dmPFC in mice suppressed fear responses, indicating that this region is required to recall associative fear-memory. Because it is connected with brain systems implicated in learning and associated psychiatric diseases, we wanted to explore how changes in the dmPFC specifically regulate new associative memory information.”

The research team used longitudinal two-photon imaging and various computational neuroscience techniques to determine how neural activity changes in the mouse prefrontal cortex after learning in a fear-conditioning paradigm. Prefrontal neurons behave in a highly complex manner, and each neuron responds to various sensory and motor events. To address this complexity, the research team developed a new analytical method based on the ‘elastic net,’ a machine-learning algorithm, to identify which specific neurons encode fear memory. They further analyzed the spatial arrangement and functional connectivity of the neurons using graphical modeling.

 “We successfully detected a neural population that encodes fear memory,” says Agetsuma. “Our analyses showed us that fear conditioning induced the formation of a fear-memory neural network with ‘hub’ neurons that functionally connected the memory neurons.”

Importantly, the researchers uncovered direct evidence that associative memory formation was accompanied by a novel associative connection between originally distinct networks, i.e., the conditioned stimulus (CS, e.g., tone) network and the unconditioned stimulus (US, e.g., fearful experience) network. “We propose that this newly discovered connection might facilitate information processing by triggering a fear response (CR) to a CS (i.e., a neural network for CS-to-CR transformation).”

Memories have long been thought to be formed by the enhancement of neural connections, which are strengthened by the repeated activation of groups of neurons. The findings of the present study, which were based on both real-life observations and model-based analysis, support this. Furthermore, the study demonstrates how combined methods (optics and machine learning) can be used to visualize the dynamics of neural networks in great detail. These techniques could be used to uncover additional information about the neurological changes associated with learning and memory.

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The article, “Activity-dependent organization of prefrontal hub-networks for associative learning and signal transformation” was published in Nature Communications at DOI:10.1038/s41467-023-41547-5

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JOURNAL

Nature Communications

DOI

10.1038/s41467-023-41547-5 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Activity-dependent organization of prefrontal hub-networks for associative learning and signal transformation

Research spotlight: Generic daily HIV prevention pill for young men who have sex with men could save lives and money

Peer-Reviewed Publication

MASSACHUSETTS GENERAL HOSPITAL

Anne Neilan, MD, a physician-scientist in the division of Infectious Diseases at Massachusetts General Hospital is the senior author of a recently published paper in Clinical Infectious Diseases, Daily Oral HIV Pre-exposure Prophylaxis Among Young Men Who Have Sex With Men in the United States: Cost-Saving at Generic Drug Price.

What Question Were You Investigating?

About one in five new HIV diagnoses in the United States occur among youth ages 13 to 24 years. Young men who have sex with men (YMSM) are account for 81% of new diagnoses in this age group in 2019. When taken daily as prescribed, oral PrEP reduces the risk of sexually acquiring HIV by about 99%. Compared to older men who have sex with men, YMSM are less likely to start PrEP and tend to have more challenges adhering to PrEP and remaining in care.

Our team wanted to understand how tenofovir-based daily oral HIV pre-exposure prophylaxis (PrEP) would compare to current CDC-recommended annual HIV screening in terms of clinical benefits and costs among U.S.-based YMSM in light of newly available generic PrEP medication and new CDC guidelines for PrEP use.
 

What Methods or Approached Did You Use?

Our research team used data from two studies conducted by NICHD’s Adolescent Medicine Trials Network for HIV Interventions. These studies examined the acceptability and feasibility of daily TDF-FTC among young men ages 15 to 22 years considered at increased risk of acquiring HIV because they because they engaged in condomless anal sex or had other sexually transmitted infections (STIs). 

What Were Your Findings?

The model projected that over 10 years, the generic PrEP strategy would reduce new HIV acquisitions from 37% to 30% and decrease costs by $5,000 per person, compared to annual screening.

The finding that PrEP would provide more benefits at lower cost held up across several scenarios, including a range of ART prices, HIV incidence rates, and PrEP retention rates.

Even if as few as 6% of young men remained in the PrEP program after six years, the strategy would still have benefits over annual screening.

Our team also found that offering generic PrEP in addition to screening every three months was more cost-saving than every-three-month screening alone.
 

What Are the Clinical Implications?

Our findings show us that we would be throwing away both lives and money by failing to implement generic PrEP in this population. Policies that create barriers to PrEP access for this population – such as the recent Braidwood Management versus Becerra case, which overrules ACA-mandated employer-based coverage for HIV PrEP – aren’t justifiable on clinical or economic grounds.

What Are the Next Steps?

Our research team’s next step is to understand the value interventions to improve access to and adherence to existing and novel HIV prevention strategies in adolescents and young adults in the US and abroad.

 

About the Massachusetts General Hospital

Massachusetts General Hospital, founded in 1811, is the original and largest teaching hospital of Harvard Medical School. The Mass General Research Institute conducts the largest hospital-based research program in the nation, with annual research operations of more than $1 billion and comprises more than 9,500 researchers working across more than 30 institutes, centers and departments.

 

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JOURNAL

Clinical Infectious Diseases

DOI

10.1093/cid/ciad566