New life cycle assessment study shows useful life of tech-critical metals to be short 

by University of Bayreuth

Global cycle of metals. Credit: Nature Sustainability (2022).

 DOI: 10.1038/s41893-022-00895-8

Worldwide, almost all technology-intensive industries depend on readily available metallic raw materials. Consequently, precise and reliable information is needed on how long these raw materials remain in the economic cycle. To obtain the necessary data, a research team from the universities of Bayreuth, Augsburg and Bordeaux has now developed a new modeling method and applied it to 61 metals. The study, published in Nature Sustainability, shows that the metals needed for specific high-tech applications, which in many cases are scarce around the world, are in use for only a decade on average.

The useful life of a metal comprises the entire period that begins with mining and ends when it dissipates—i.e., is finely dispersed—in the environment, and is no longer available for economic use. Iron and steel alloy metals have the longest useful life, averaging 150 years. The researchers see the reason for this primarily in the high efficiency of the industrial processes in which these metals are processed, as well as in high recycling rates. The lifespan of non-ferrous metals such as aluminum and copper and precious metals such as gold and silver is significantly shorter, but it is still over 50 years. By contrast, the technology-specific and in some cases critical—i.e. hardly available—metals only remain in the economic cycle for about twelve years. Cobalt and indium are examples of this large group of raw materials. For all these calculations, data from the Bureau de Recherches Géologiques et Minières (BRGM), a geoscientific institute based in Paris and Orléans, was used.

One thing all of the 61 metals studied have in common is that the quantities lost to the economic cycle over time must be constantly compensated for by new mining. The greater the losses, the more resources are irretrievably lost, and the more damaging the consequences are for the climate and the environment.

"It is in the urgent interest of the world's population to extend the useful life of metals and to strive for economic cycles that are as closed as possible to prevent these huge losses. However, these goals can only be achieved if the useful life of every raw material relevant to our technology can be extended and calculated with greater statistical accuracy," says Prof. Dr. Christoph Helbig, Chair of the newly established Ecological Resource Technology research group at the University of Bayreuth. The aim of his research is to increase the useful life of metallic resources, and in this way contribute to environmentally and climate-friendly industries.

The calculations now published in Nature Sustainability are based on a new modeling method developed by the authors, with which the useful life of metals can be calculated far more reliably than with the usual measurements based on recycling rates. The special feature of this statistical method is that it can be applied equally to almost all metals of the periodic table. This is a decisive prerequisite for the data obtained to be comparable. Only in this way can they form a reliable basis for life cycle assessments that provide information on the extent to which valuable raw materials are being used efficiently or wasted. Life cycle assessments in the area of abiotic raw materials look set to be considerably more meaningful thanks to the research results achieved by the study.

Prof. Dr. Christoph Helbig started work on the new study while still at the University of Augsburg and brought the topic to Bayreuth: "I am very much looking forward to continuing and developing the existing cooperation with working groups in Bordeaux and Augsburg at the University of Bayreuth," says Helbig. The University of Bordeaux is one of the partner institutions of the Gateway Office which the University of Bayreuth set up two years ago to further expand its international networking in research and teaching.New technology dramatically increases the recovery rate of precious metals 

  information: Alexandre Charpentier Poncelet et al, Losses and lifetimes of metals in the economy, Nature Sustainability (2022). DOI: 10.1038/s41893-022-00895-

Journal information: Nature Sustainability 

Provided by University of Bayreuth 

Ancient crocodile found in Peru sheds new light on their origin

Credit: Pixabay/CC0 Public Domain

A team of researchers at Universidad Peruana Cayetano Heredia, working with colleagues from the U.S. and France, has uncovered a prehistoric crocodile fossil in Peru. In their paper published in Proceedings of the Royal Society B, the group describes their find, what they have learned about it and what it shows about the evolution of marine crocodiles.

Though there are two species of modern crocodiles that live in the ocean, they are predominantly freshwater dwelling creatures. This feature, the researchers with this new effort note, makes it difficult to understand the evolution of the creatures from crocs that predominantly lived in the sea in the past. Also, prior research has suggested that crocodiles have been living in southeastern parts of the Pacific Ocean for approximately 14 million years. In this new effort, the researchers have been looking for evidence of early crocodiles in western parts of South America, most specifically, Peru. And as part of that effort, they have uncovered the partial remains of an ancient crocodile.

The crocodile fossil (a skull and jaw) was uncovered in East Pisco Basin, (in the Sacaco desert) in Peru in 2020. Since that time, the researchers have been studying its attributes and characteristics and have been seeking to find its place in the evolutionary history of crocodiles. Their testing has shown that the fossil is from approximately 7 million years ago. They have named it Sacacosuchus cordovai and have concluded that when alive, it would have been approximately four meters long.

The Sacaco site has been under study for a number of years: Prior fossil discoveries have shown that millions of years ago, the entire area was under the sea. Finding the crocodile fossil in the area suggests it was a saltwater creature, a finding that helps trace the evolution of crocodiles in South America.

The researchers suggest crocodiles made their way to South America by crossing the Atlantic Ocean. From there, some may have followed the coastline to arrive at what is now Peru. They further suggest that such marine crocodiles would have all had long thin faces and that there were two main types: one that lived almost exclusively on fish, and another that had a more varied diet.Four endangered American crocodiles are born in Peru

More information: Rodolfo Salas-Gismondi et al, Miocene fossils from the southeastern Pacific shed light on the last radiation of marine crocodylians, Proceedings of the Royal Society B: Biological Sciences (2022). DOI: 10.1098/rspb.2022.0380

Journal information: Proceedings of the Royal Society B 

© 2022 Science X Network

New study explains how to broaden strategy to avert catastrophic climate change

by University of California - San Diego

Credit: CC0 Public Domain

Slashing emissions of carbon dioxide, by itself, cannot prevent catastrophic global warming. But a new study concludes that a strategy that simultaneously reduces emissions of other largely neglected climate pollutants would cut the rate of global warming in half and give the world a fighting chance to keep the climate safe for humanity.

Published this week by the Proceedings of the National Academy of Sciences, the study is the first to analyze the importance of cutting non-carbon dioxide climate pollutants vis-à-vis merely reducing fossil fuel emissions, in both the near-term and mid-term to 2050. It confirms increasing fears that the present almost exclusive focus on carbon dioxide cannot by itself prevent global temperatures from exceeding 1.5 degrees Celsius above pre-industrial levels, the internationally accepted guardrail beyond which the world's climate is expected to pass irreversible tipping points.

Indeed, such decarbonization alone would be unlikely to stop temperatures from exceeding even the much more hazardous 2 degrees Celsius limit.

The study—by scientists at Georgetown University, Texas A&M University, Scripps Institution of Oceanography at UC San Diego, and others—concludes that adopting a dual strategy that simultaneously reduces emissions of both carbon dioxide and the other climate pollutants would cut the rate of warming in half by 2050, making it much more likely to stay within these limits.

The non-carbon dioxide pollutants include methane, hydrofluorocarbon refrigerants, black carbon soot, ground-level ozone smog, as well as nitrous oxide. The study calculates that together these pollutants currently contribute almost as much to global warming as carbon dioxide. Since most of them last only a short time in the atmosphere, cutting them slows warming faster than any other mitigation strategy.

Until now, however, the importance of these non-carbon dioxide pollutants has been underappreciated by scientists and policymakers alike, and largely neglected in efforts to combat climate change.

Recent reports by the Intergovernmental Panel on Climate Change conclude that cutting fossil fuel emissions—the main source of carbon dioxide—by decarbonizing the energy system and shifting to clean energy, in isolation, actually makes global warming worse in the short term. This is because burning fossil fuels also emits sulfate aerosols, which act to cool the climate, and these are reduced along with the carbon dioxide when switching to clean energy. These cooling sulfates fall out of the atmosphere fast, within days to weeks, while much of carbon dioxide lasts hundreds of years, thus leading to overall warming for the first decade or two.

The new study accounts for this effect and concludes that focusing exclusively on reducing fossil fuel emissions could result in "weak, near-term warming" which could potentially cause temperatures to exceed the 1.5 degrees Celsius level by 2035 and the 2 degrees Celsius level by 2050.

In contrast, the dual strategy that simultaneously reduces the non-carbon dioxide pollutants, especially the short-lived pollutants, would enable the world to stay well below the 2 degrees Celsius limit, and significantly improve the chance of remaining below the 1.5 degrees Celsius guardrail.

Indeed, a key insight from the study is the need for climate policies to address all of the pollutants that are emitted from fossil fuel sources such as coal power plants and diesel engines rather than considering just carbon dioxide or methane individually, as is common.

Continuing to slash fossil fuel carbon dioxide emissions remains vital, the study emphasizes, since that will determine the fate of the climate in the longer term beyond 2050. Phasing out fossil fuels also is essential because they produce air pollution that kills over eight million people every year and causes billions of dollars of damage to crops.

Tackling both carbon dioxide and the short-lived pollutants at the same time offers the best and the only hope of humanity making it to 2050 without triggering irreversible and potentially catastrophic climate change.Increase in atmospheric methane set new record in 2021: NOAA

More information: Gabrielle B. Dreyfus et al, Mitigating Climate Disruption in Time: A self-consistent approach for avoiding both near-term and long-term global warming, Proceedings of the National Academy of Sciences (2022). DOI: 10.1073/pnas.2123536119

Journal information: Proceedings of the National Academy of Sciences 

Provided by University of California - San Diego 

Interprofessional collaboration leads to significant and sustained reduction in hospital-onset c. difficile infections

Community hospital reduced infections by 63% after one year and 77% after three years

Peer-Reviewed Publication

ASSOCIATION FOR PROFESSIONALS IN INFECTION CONTROL

Arlington, Va., May 12, 2022 – A new study published today in the American Journal of Infection Control (AJIC), suggests that health care facilities can significantly reduce the incidence of hospital-onset Clostridioides difficile infection (HO-CDI) by establishing interprofessional teams to implement selected, evidence-based infection-prevention interventions.

“Our project showed that interprofessional collaboration and continuous improvement can profoundly impact HO-CDI incidence, and sustain reductions over years,” said Cherith Walter, MSN, RN, Emory St. Joseph’s Hospital, and first author on the published study. “We hope our findings will help other healthcare teams struggling with this incredibly challenging healthcare-associated infection to improve patient safety and reduce associated costs.”

According to the Centers for Disease Control and Prevention, an estimated 500,000 cases of CDI occur in the United States annually[1], making it one of the most prevalent healthcare-associated infections (HAI) in the country. Due to the cost of caring for patients with HO-CDI, as well as financial penalties levied under the Centers for Medicare and Medical Services’ (CMS) hospital-acquired condition reduction program, these infections have increased the financial burden on the healthcare system.

To address the HO-CDI incidence at their 410-bed community hospital, which was consistently above the national CMS benchmark, Walter and colleagues created an interprofessional team comprising a clinical nurse specialist, a physician champion, a hospital epidemiologist, an infection preventionist, a clinical microbiologist, unit nurse champions, an antimicrobial stewardship pharmacist, and an environmental services representative. The team reviewed HO-CDI events at their facility between 2014 and 2016 to determine causative factors, and then identified appropriate, evidence-based infection prevention interventions. The selected interventions comprised diagnostic stewardship, including the development of a Diarrhea Decision Tree (DDT) testing algorithm with a nurse-driven ordering protocol; enhanced environmental cleaning; antimicrobial stewardship, including a system-wide Electronic Medical Record intervention to reduce fluoroquinolone use; and education and accountability, the latter of which focused on encouraging compliance with the DDT algorithm.

After the first year, the project leads recorded a 63% decrease in HO-CDIs as compared to the two years prior (4.72 per 10,000 patient days vs. 12 per 10,000 patient days). This number improved further to 2.8 per 10,000 days three years after implementation of the selected interventions (a 77% decrease from baseline). The team also saw a decrease in their facility’s standardized HO-CDI infection ratio (the total number of infections divided by the National Health Safety Network’s risk-adjusted predicted number of infections), from 1.11 in 2015 to 0.43 in 2020 – significantly lower than the national benchmark.

Interventions also improved CDI testing practices, increasing testing for appropriate patients within the first three days of hospital admission from 54% in 2014 to 81.1% in late 2019, to support prompt treatment of infected patients. This practice also helped identify and differentiate cases of community-acquired CDI (CA-CDI) from HO-CDI, reducing the financial impact of HO-CDIs on the facility after 2016. Finally, by empowering nurses to hold providers accountable for judicious test ordering and creating a system of ‘accountability notices’ alerting nurses and providers to DDT algorithm deviations, the team successfully increased compliance with the algorithm, from 50% in mid-2018 to 80% in mid-2020.

“These study findings are exciting, because they suggest that professional collaboration to consistently apply known, evidence-based practices can significantly reduce the incidence of HO-CDI, an intractable and costly HAI,” said Linda Dickey, RN, MPH, CIC, FAPIC, and 2022 APIC president. “They are also the first findings demonstrating the impact of education and accountability interventions in reducing HO-CDI incidence and improving compliance with standards of practice.”

 About APIC

Founded in 1972, the Association for Professionals in Infection Control and Epidemiology (APIC) is the leading association for infection preventionists and epidemiologists. With more than 15,000 members, APIC advances the science and practice of infection prevention and control. APIC carries out its mission through research, advocacy, and patient safety; education, credentialing, and certification; and fostering development of the infection prevention and control workforce of the future. Together with our members and partners, we are working toward a safer world through the prevention of infection. Join us and learn more at apic.org.

About AJIC

As the official peer-reviewed journal of APIC, The American Journal of Infection Control (AJIC) is the foremost resource on infection control, epidemiology, infectious diseases, quality management, occupational health, and disease prevention. Published by Elsevier, AJIC also publishes infection control guidelines from APIC and the CDC. AJIC is included in Index Medicus and CINAHL. Visit AJIC at ajicjournal.org.

NOTES FOR EDITORS

“An Interprofessional Approach to Reducing Hospital-Onset Clostridioides difficile Infections,” by Cherith Walter, MSN, RN; Tanushree Soni, PhD, MPH; Melanie Alice Gavin, MPH; Julianne Kubes, MPH; and Kristen Paciullo, PharmD, was published online in AJIC on May 12, 2022. The article may be found online at:  https://doi.org/10.1016/j.ajic.2022.02.017

 

AUTHORS

Cherith Walter, MSN, RN, APRN, AGPCNP-BC, AGCNS-BC (corresponding author: cherith.walter@emoryhealthcare.org)

Emory Saint Joseph’s Hospital, Atlanta, GA, USA

 

Tanushree Soni, PhD, MPH, CIC

Emory Saint Joseph’s Hospital, Atlanta, GA, USA

 

Melanie Alice Gavin, MPH, CIC, M (ASCP)

Emory Saint Joseph’s Hospital, Atlanta, GA, USA

 

Julianne Kubes, MPH

Emory Healthcare, Atlanta, GA, USA

 

Kristen Paciullo, PharmD, BCIDP

Emory Saint Joseph’s Hospital, Atlanta, GA, USA

 

# # #

 

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[1] Guery B, Galperine T, Barbut F. Clostridioides difficile: diagnosis and treatments. BMJ. 2019 Aug 20;366:l4609.

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JOURNAL

American Journal of Infection Control

DOI

10.1016/j.ajic.2022.02.017 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

People

ARTICLE TITLE

An Interprofessional Approach to Reducing Hospital-Onset Clostridioides difficile Infections

How we perceive crowds

Slow walking may be to blame for perceived congestion in pedestrian areas

Peer-Reviewed Publication

UNIVERSITY OF TOKYO

 

IMAGE: IT MIGHT LOOK LIKE SOMETHING FROM A PHYSICS PAPER, BUT THIS IS ACTUALLY A PLOT SHOWING HOW PEOPLE’S PERCEPTIONS OF AN ENCLOSED SPACE CHANGE DEPENDING ON HOW IMPEDED THE CROWD WAS BY AN OBSTACLE. BLUE COLORS REFLECT PEOPLE WITHIN THE CROWD WHO WERE MORE FRUSTRATED IN THE SPACE, AND RED COLORS REFLECT PEOPLE WHO WERE MORE AT EASE. IN EACH CASE, W IS THE WIDTH OF THE OBSTACLE, AND D IS THE DISTANCE BETWEEN THE OBSTACLE AND THE EXIT. view more 

CREDIT: ©2022 JIA XIAOLU ET AL.

When designing public spaces or other places where foot traffic is considered, planners and architects need to know how people perceive the spaces in question. It is commonly believed that a space will feel more congested if the crowd density is higher. However, new research suggests that walking speed of individuals actually plays a greater role than crowd density in how someone feels about a busy space. Also, age and gender seem to affect someone’s perception of how congested an enclosed space feels to them.

If you live in a town or city, you are probably experienced in the art of navigating through crowded areas. But sometimes you can’t help but feel like your surroundings are too congested for comfort. Intuition tells us this feeling must be because of the sheer volume of people around us in these moments that causes the perception of somewhere being too congested. But Project Assistant Professor Jia Xiaolu from the Research Center for Advanced Science and Technology at the University of Tokyo wanted to verify this assumption, and ended up proving that it might not actually be the entire truth of the matter.

“Perception of congestion is an important matter for those designing spaces to be used by people, so if there’s a way to estimate this perceptual value, it would be useful to know,” said Xiaolu. “Thus, I was a little surprised to find that the density of people in a given space was not the best indicator of perceived congestion; in fact, it turned out to be the walking speed, or velocity, of the people around the perceiver.”

In order to determine this, Xiaolu and her team first had to set up an elaborate experiment. They recruited a large number of people to play the part of a crowd. The crowd was asked to walk through a relatively narrow space made out of cardboard boxes with an exit at the end and an obstacle made from boxes just before it. The researchers repeated the experiment but changed the size of the obstacle to choke the flow of the crowd, all the while recording the motions of people by using a camera and motion-tracking software.

Alongside this physical task, the crowd were also given questionnaires to fill out that captured more qualitative information about their perceptions of the crowded space during these repeated trials. By combing both quantitative and qualitative data, the researchers hoped to find a relationship between some of the quantitative parameters of the crowd and the qualitative perceptions of the crowd members.

“That the velocity of pedestrians rather than density of the crowd better indicates perceived congestion was a bit of a surprise,” said Xiaolu. “But it leads us to believe that people perceive a space too congested when they are simply unable to walk at the speed they wish to; there is a gap between their desired and actual velocity. This idea corresponds with the way people felt depending on where they were in the test space. In trials where the density was roughly uniform, slower groups around the obstacle led to those in the vicinity reporting feelings of congestion more than those prior to that section.”

The study suggests that overtaking where possible might make some people feel less constrained by the congestion, but other studies of crowd dynamics by Xiaolu and her team report that overtaking behavior can negatively impact the flow of the crowd as a whole. The team also found some noteworthy details when they analyzed the way different demographics responded to tests.

“We found that women and also older people generally felt less constrained than men and younger people, which is probably due to their lower desired velocity, thus a smaller gap between their desired and actual velocity,” said Xiaolu. “And while this is interesting, I think our future studies will focus on spaces where the objective is not so much about getting from A to B, but more goal oriented, such as interacting with a service in a store, gallery or other destination.”

  

CAPTION

These are four different methods for measuring and visualizing density, in this case, the density of people within a physically constrained space.

CREDIT

©2022 Jia Xiaolu et al.

Journal article: Xiaolu Jia, Claudio Feliciani, Hisashi Murakami, Akihito Nagahama, Daichi Yanagisawa, Katsuhiro Nishinari. “Revisiting the level-of-service framework for pedestrian comfortability: velocity depicts more accurate perceived congestion than local density”. Transportation Research. https://doi.org/10.1016/j.trf.2022.04.007

Funding: This work was supported by the following Japanese grants: JSPS KAKENHI Grant Number JP21K14377, JP20K14992, JP20K20143, JP21H01570 and JP21H01352, and JST-Mirai Program Grant Number JPMJMI17D4 and JPMJMI20D1, Japan. This research was also partially supported by FONDAZIONE CARIPLO (Italy), “LONGEVICITY-Social Inclusion for the Elderly through Walkability”, Rif. 2017-0938.

Useful links:
Mobility Innovation Collaborative Research Organization
http://www.its.iis.u-tokyo.ac.jp/utmobi/en/  
 

Research Center for Advanced Science and Technology

https://www.rcast.u-tokyo.ac.jp/en/
 

Research Contact

Project Assistant Professor Jia Xiaolu

Research Center for Advanced Science and Technology, The University of Tokyo,
4-6-1, Komaba, Meguro-ku, Tokyo 153-8904, JAPAN

Email: xiaolujia@g.ecc.u-tokyo.ac.jp

Press contact:
Mr Rohan Mehra
Public Relations Group, The University of Tokyo
7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
email: press-releases.adm@gs.mail.u-tokyo.ac.jp

About The University of Tokyo
The University of Tokyo is Japan's leading university and one of the world's top research universities. The vast research output of some 6,000 researchers is published in the world's top journals across the arts and sciences. Our vibrant student body of around 15,000 undergraduate and 15,000 graduate students includes over 4,000 international students. Find out more at www.u-tokyo.ac.jp/en/ or follow us on Twitter at @UTokyo_News_en.

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JOURNAL

Transportation Research

DOI

10.1016/j.trf.2022.04.007 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Revisiting the level-of-service framework for pedestrian comfortability: velocity depicts more accurate perceived congestion than local density

How does climate change affect the locust bean?

Peer-Reviewed Publication

UNIVERSITAT POLITÈCNICA DE VALÈNCIA

 

IMAGE: HOW DOES CLIMATE CHANGE AFFECT THE LOCUST BEAN? view more 

CREDIT: UPV

A team of researchers from the Universitat Politècnica de València (UPV), belonging to the Instituto Universitario de Conservación y Mejora de la Agrodiversidad Valenciana (COMAV), and the Universidad Técnica Particular de Loja (Ecuador) has evaluated the effects of climatic conditions on local and commercial varieties of beans (Phaseolus vulgaris), garrofón (P. lunatus) and green beans (Vigna unguiculata) traditionally sown under cold or hot conditions.

By subjecting these varieties to different temperatures, the researchers have evaluated the impact of the effects of climate change on vital parameters of these varieties, such as their morphology, reproduction, production, and phenology. Thus, they have detected some very sensitive types to variations in their conditions of origin. These others perform better with the increase in temperature, and others are highly resilient to any change.

The study is led by the COMAV researcher at the UPV, Mario X. Ruiz, who stresses that "during the research, we have identified the most fragile varieties in the face of the effects of climate change, which is why it is a priority to preserve them".

Thus, this study shows that some bean varieties perform better at higher temperatures, making them an excellent alternative to replace less productive types due to climate change. One local variety even proved to be more resistant than the commercial variety used as a control. Green beans (bachoqueta), whose origin is African, resisted relatively well to increases in temperature, as did locust beans.

The research also highlights the importance of considering the environmental and ecological background from which the varieties under study originate. In short, the results obtained have an immediate application in the conservation of agrobiodiversity by revealing which varieties are most sensitive to the effects of climate change and which should be conserved as a priority.

It also highlights the importance of promoting the resilience of food sovereignty in the face of environmental challenges, as identifying those varieties best adapted to the new conditions will allow crops to be implemented locally.

In plant breeding, the identification of traits most affected by the environment will enable crop improvement, as this research not only helps to boost adaptation to climate change but also to other disasters such as the COVID-19 pandemic, which has led to a shortage in the supply of commercial seeds in developing communities.

In this sense, Mario X. Ruiz stresses that "the pandemic has produced a shortage of commercial seeds in developing communities. Thanks to our research, we can find the best alternatives to maintain production locally".

The results of this study have been published in the journal Scientific Reports.

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JOURNAL

Scientific Reports

DOI

10.1038/s41598-022-10277-x 

METHOD OF RESEARCH

Meta-analysis

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Heterogeneous effects of climatic conditions on Andean bean landraces and cowpeas highlight alternatives for crop management and conservation

Algae-powered computing: Scientists create reliable and renewable biological photovoltaic cell

Peer-Reviewed Publication

UNIVERSITY OF CAMBRIDGE

 

IMAGE: THIS SYSTEM, CONTAINING BLUE-GREEN ALGAE, POWERED A MICROPROCESSOR CONTINUOUSLY FOR A YEAR USING NOTHING BUT AMBIENT LIGHT AND WATER. view more 

CREDIT: PAOLO BOMBELLI

Researchers have used a widespread species of blue-green algae to power a microprocessor continuously for a year - and counting - using nothing but ambient light and water. Their system has potential as a reliable and renewable way to power small devices.

The system, comparable in size to an AA battery, contains a type of non-toxic algae called Synechocystis that naturally harvests energy from the sun through photosynthesis. The tiny electrical current this generates then interacts with an aluminium electrode and is used to power a microprocessor.

The system is made of common, inexpensive and largely recyclable materials. This means it could easily be replicated hundreds of thousands of times to power large numbers of small devices as part of the Internet of Things. The researchers say it is likely to be most useful in off-grid situations or remote locations, where small amounts of power can be very beneficial.

“The growing Internet of Things needs an increasing amount of power, and we think this will have to come from systems that can generate energy, rather than simply store it like batteries,” said Professor Christopher Howe in the University of Cambridge’s Department of Biochemistry, joint senior author of the paper.

He added: “Our photosynthetic device doesn’t run down the way a battery does because it’s continually using light as the energy source.”

In the experiment, the device was used to power an Arm Cortex M0+, which is a microprocessor used widely in Internet of Things devices. It operated in a domestic environment and semi-outdoor conditions under natural light and associated temperature fluctuations, and after six months of continuous power production the results were submitted for publication.

The study is published today in the journal Energy & Environmental Science.

“We were impressed by how consistently the system worked over a long period of time – we thought it might stop after a few weeks but it just kept going,” said Dr Paolo Bombelli in the University of Cambridge’s Department of Biochemistry, first author of the paper.

The algae does not need feeding, because it creates its own food as it photosynthesises. And despite the fact that photosynthesis requires light, the device can even continue producing power during periods of darkness. The researchers think this is because the algae processes some of its food when there’s no light, and this continues to generate an electrical current.

The Internet of Things is a vast and growing network of electronic devices - each using only a small amount of power - that collect and share real-time data via the internet. Using low-cost computer chips and wireless networks, many billions of devices are part of this network - from smartwatches to temperature sensors in power stations. This figure is expected to grow to one trillion devices by 2035, requiring a vast number of portable energy sources.

The researchers say that powering trillions of Internet of Things devices using lithium-ion batteries would be impractical: it would need three times more lithium than is produced across the world annually. And traditional photovoltaic devices are made using hazardous materials that have adverse environmental effects.

The work was a collaboration between the University of Cambridge and Arm, a company leading the design of microprocessors. Arm Research developed the ultra-efficient Arm Cortex M0+ testchip, built the board, and set up the data-collection cloud interface presented in the experiments.

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JOURNAL

Energy & Environmental Science

DOI

10.1039/D2EE00233G 

ARTICLE TITLE

Powering a Microprocessor by Photosynthesis

Sugar aversion hampers cockroach coupling

Peer-Reviewed Publication

NORTH CAROLINA STATE UNIVERSITY

 

IMAGE: MALE COCKROACHES ATTRACT FEMALES BY PROVIDING A ROACH VERSION OF CHOCOLATE - SUGARS AND FATS. GLUCOSE-AVERSE FEMALES, HOWEVER, SOMETIMES FLEE WHEN THEIR SALIVA TURNS THE SWEET TREAT INTO A BITTER PILL. view more 

CREDIT: AYAKO WADA-KATSUMATA

Cockroach Courtship and Mating (VIDEO)

 
A new study from North Carolina State University shows the behavioral mechanism behind a sweet cockroach mating ritual that takes a bitter turn, resulting in rejected males.

Male German cockroaches (Blattella germanica) offer females a pre-mating “gift” of body secretions that combines sugars and fats – think of the roach version of chocolate – in order to attract and hold female attention long enough to start copulation.

“This is common mating behavior in insects and some other animals: males present females a tasty or valuable gift – it’s like Valentine’s Day, but every day,” said Coby Schal, Blanton J. Whitmire Distinguished Professor of Entomology at NC State and co-corresponding author of the paper.

The study shows, however, that females averse to the simple sugar glucose get an unpleasant surprise when they mix their saliva with the male secretions – saliva degrades the sweet treat of complex sugars to glucose, which becomes a bitter pill that ends the courtship ritual, with the female scurrying away without mating.

“We’re seeing glucose-averse female German cockroaches turning down this nuptial gift – and the chance to mate – and wanted to understand more about the mechanism behind it,” said Ayako Wada-Katsumata, principal research scholar at NC State and co-corresponding author of the paper.

Generally, cockroaches love sugar. But some have developed an aversion to glucose; Wada-Katsumata in 2013 published a paper that showed the neural mechanism behind this aversion in German cockroaches, a behavior that perhaps has become more pronounced due to the presence of the simple sugar in roach baits placed inside homes. In a 2021 paper, Wada-Katsumata and Schal showed that cockroach saliva converts complex sugars into glucose.

“Male cockroach secretions have different types of sugars – in this case maltose and maltotriose, which are usually preferred by females – as well as some fats,” Wada-Katsumata said. Maltose is relatively easy to convert to glucose, while maltotriose is more complex and takes a bit longer to break down into glucose, she said.

“Cockroach saliva has a class of chemicals that breaks down sugars,” Schal said. “As females feed on their gift, maltose is rapidly converted to glucose, and glucose-averse females sense a bitter taste and stop feeding, which also ends the mating opportunity.”

The cockroach mating process is interesting but likely unfamiliar to bipeds. Males approach females, raise their wings, and release chemicals via the tergal gland on their backs. Females attracted to the secretion will climb onto the male’s back and feed on the secretion. While she feeds, the male will telescope his abdomen under the female, grab her with an elongated hooked penis and move into position for mating. This courtship process takes only seconds; it is here that the rapid chemical conversion of complex sugars to simple sugars in saliva could kill the mood for glucose-averse females. If successful, though, roaches engage in a back-to-back, up to 90-minute-long mating session, with the male using a second penis to transfer a sperm package to the female. 

In the study, the researchers performed various experiments to ascertain how glucose aversion affects cockroach courtship. They found that glucose-averse females more frequently interrupted feeding due to their aversion, especially when feeding from a wild-type male – one that was not averse to glucose. Glucose-averse males often had higher levels of maltotriose in their secretions, which converted less easily to glucose and therefore gave those males extra time to begin mating.

The researchers also changed the quality of the male secretion, substituting fructose for the glucose and maltose secretions. Glucose-averse females enjoyed fructose and fed on it longer, resulting in more successful mating sessions.

“This study is a direct way to show that the quality of secretion affects female behavior and mating success,” Schal said. “There is a tradeoff between sexual selection and natural selection. Think of deer as an example. Male deer have horns, not for natural selection – horns actually put males in danger from predators and hunters – but for sexual selection to appeal to females and serve as useful weapons in competition with other males. Similarly, the cockroach’s tergal gland evolved for attracting females in the context of sexual selection.”

“Wild-type females accept the sugary secretions. Glucose-averse females don’t accept the wild-type secretions because they easily convert to glucose. Males can change the composition of secretions – perhaps producing more maltotriose which takes longer to convert to glucose – or try to mate faster. In short, the glucose aversion trait evolved under natural selection, but under sexual selection it is causing the male to modify his sexual secretion and behavior,” Wada-Katsumata said.

The 2013 study informed bait manufacturers not to use glucose in baits. The 2021 studies expand this recommendation to all sugars that contain glucose. Baits made with glucose, sucrose, maltose and other sugars will be ignored by glucose-averse cockroaches. As more cockroaches with glucose aversion survive, that trait will be passed down in greater numbers.

“We are constantly in an evolutionary battle with cockroaches,” Schal said. “Evolution can be sped up tremendously in the urban, human environment because the selection force imposed on insects, especially inside homes, is so intense.”

The study appears in Nature Communications Biology. Postdoctoral scholar Eduardo Hatano, Ph.D. student Samantha McPherson and Jules Silverman, Charles G. Wright Distinguished Emeritus Professor of Entomology, co-authored the paper. The research was supported by the National Science Foundation under grant IOS-1557864, the U.S. Department of Housing and Urban Development Healthy Homes program (NCHHU0053-19), and the Blanton J. Whitmire Endowment at NC State.

- kulikowski -

Note to editors: An abstract of the paper follows.

“Rapid evolution of an adaptive taste polymorphism disrupts courtship behavior”
Authors: Ayako Wada-Katsumata, Eduardo Hatano, Samantha McPherson, Jules Silverman and Coby Schal, North Carolina State University

Published: May 12, 2022 in Nature Communications Biology

DOI: 10.1038/s42003-022-03415-8

Abstract: The evolution of adaptive behavior often requires changes in sensory systems. However, rapid adaptive changes in sensory traits can adversely affect other fitness-related behaviors. In the German cockroach, a gustatory polymorphism, ‘glucose-aversion (GA)’, supports greater survivorship under selection with glucose-containing insecticide baits and promotes the evolution of behavioral resistance. Yet, sugars are prominent components of the male’s nuptial gift and play an essential role in courtship. Behavioral and chemical analyses revealed that the saliva of GA females rapidly degrades nuptial gift sugars into glucose, and the inversion of a tasty nuptial gift to an aversive stimulus often causes GA females to reject courting males. Thus, the rapid emergence of an adaptive change in the gustatory system supports foraging, but it interferes with courtship. The trade-off between natural and sexual selection under human-imposed selection can lead to directional selection on courtship behavior that favors the GA genotype.
 

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JOURNAL

Communications Biology

DOI

10.1038/s42003-022-03415-8 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

“Rapid evolution of an adaptive taste polymorphism disrupts courtship behavior”