Culture

Using the X-ray laser European XFEL, a research team has investigated how water heats up under extreme conditions. In the process, the scientists were able to observe water that remained liquid even at temperatures of more than 170 degrees Celsius. The investigation revealed an anomalous dynamic behaviour of water under these conditions. The results of the study, which are published in the Proceedings of the National Academy of Sciences (PNAS), are of fundamental importance for the planning and analysis of investigations of sensitive samples using X-ray lasers.

European XFEL, an international research facility, which extends from the DESY site in Hamburg to the neighbouring town of Schenefeld in Schleswig-Holstein, is home to the most powerful X-ray laser in the world. It can generate up to 27 000 intense X-ray flashes per second. For their experiments, the researchers used series of 120 flashes each. The individual flashes were less than a millionth of a second apart (exactly 0.886 microseconds). The scientists sent these pulse trains into a thin, water-filled quartz glass tube and observed the reaction of the water.

"We asked ourselves how long and how strongly water can be heated in the X-ray laser and whether it still behaves like water," explains lead author Felix Lehmkühler from DESY. "For example, does it still function as a coolant at high temperatures?" A detailed understanding of superheated water is also essential for a large number of investigations on heat-sensitive samples, such as polymers or biological samples.

"With the X-ray flashes, we were able to heat the water up to 172 degrees Celsius within a ten thousandth of a second without it evaporating," reports Lehmkühler. Such a boiling delay can normally only be observed up to about 110 degrees Celsius. "But that is not the only anomalous feature," the physicist emphasises. The scientists investigated the movement of silicon nanospheres floating in the water as markers for the dynamics in the sample. "In the extremely overheated water, we observed that the movement of silicon dioxide nanospheres deviated significantly from the expected random Brownian molecular movement. This indicates an uneven heating of the sample," says Lehmkühler. Existing theoretical models cannot yet satisfactorily explain this behaviour because they are not designed for water under these extreme conditions.

Thanks to the rapid flash sequence of the European XFEL, the researchers were able to observe the process in extreme detail. "What makes the European XFEL unique is the high repetition rate, that is, the high number of pulses per second", explains co-author Adrian Mancuso, head of the SPB/SFX instrument at the European XFEL where the experiments took place. "And we have all the instrumentation in place - such as fast cameras, diagnostics and more - to make these experiments possible". For instance, the Adaptive Gain Integrating Pixel Detector (AGIPD) developed by a DESY-led consortium can take around 350 serial images at intervals of only 220 billionths of a second (nanoseconds).

This setup not only allowed the superheated water to be generated, but also enabled the scientists to carry out precisely controlled series of experiments with X-ray flashes of reduced intensity. "Using silicon filters, we fine-tuned the energy of the pulses so that we were able to control exactly how much the water was heated," reports Lehmkühler. "For example, we were able to determine how strong the X-ray flashes should be so that the temperature of an aqueous sample remains more or less constant".

This enables researchers to better plan experiments with heat-sensitive samples at the X-ray laser, for example. On the other hand, the heating effect can also be used in a targeted manner if its exact course is known. The team plans to further investigate these effects also within the framework of the Centre for Molecular Water Science (CMWS), which is currently being set up at DESY.

"Our results not only provide the surprising observation of an anomalous dynamic, but also draw a detailed picture of how aqueous samples heat up in the X-ray laser," summarises lead researcher Gerhard Grübel from DESY, one of the CMWS coordinators. "In addition, the investigations prove that such serial images are possible at the European XFEL and that its flashes are extremely uniform in every pulse train".

These results from studies in both experimental and theoretical physics may help to improve antibacterial surfaces. The research work was recently published in the journal 'Nanoscale'.

Staphylococcus aureus bacteria are one of the most common causes of infections acquired by patients during a stay in hospital. These pathogens are particularly problematic because they can form robust biofilms on both natural and artificial surfaces from which they are very difficult to remove. 'The individual bacteria within these biofilms are effectively protected from attack by antibiotics or by the human immune system. That's why it can be so dangerous when these bacteria colonize medical implants as they can then cause serious post-operative infections,' explains Karin Jacobs, Professor of Experimental Physics at Saarland University. It is therefore crucial to try and prevent these biofilms from forming in the first place.

However, to be able to influence biofilm growth, the researchers had to understand the mechanisms by which the bacteria adhere to different materials. Using a scanning atomic force microscope, they pressed the minute bacterial cells onto different types of surfaces and then determined the force needed to lift the adhered cells from the surface. This experimental configuration allowed the researchers to record what are known as force-distance curves. 'We used extremely smooth silicon surfaces as model surfaces. In one set of experiments, the silicon surfaces were prepared so that they had high water-wettability; in another set of experiments they were treated to be highly hydrophobic. We were able to show that the bacterial cells adhered far more strongly to the hydrophobic surfaces, from which water simply rolled off, than on the hydrophilic (water-wettable) surfaces,' explains Karin Jacobs. But it is not just the magnitude of the forces that differ between the two surface types, so too do the shapes of the force-distance curves (see figure). 'On the hydrophobic surfaces, we see very smooth curves with a characteristic cup shape. On the hydrophilic surfaces, in contrast, we observe force-distance curves with a very jagged profile,' says Professor Jacobs.

In order to understand these results, the dynamics of these complex systems were modelled using Monte Carlo simulations that were carried out in the research group led by Professor Ludger Santen, Professor of Theoretical Physics at Saarland University. The model treats the bacterial cell as a rigid sphere and the molecules in the cell wall that tether the cell to the surface as minute springs. 'It turns out that in order to reproduce the experimental results, the role played by the random (stochastic) nature of the molecular binding process is more important than trying to increase the complexity of the model. We have now uncovered why the bacteria cells behave so differently on different types of surfaces. On hydrophobic surfaces, a large number of the cell wall proteins adhere to the surface, which results in a strong binding force and yields a smooth force-distance curve,' explains Ludger Santen. In contrast, on a hydrophilic surface, far fewer cell wall proteins are involved in tethering the bacterium to the surface. As a result, the bacteria are held less strongly on the surface and the shape of the force-distance curve is less uniform. 'The jagged shape of the curves that we see with hydrophilic surfaces is caused by a few individual cell wall molecules as they are pulled from the surface. Because fewer cell wall proteins are involved, the bacteria bind less strongly to hydrophilic surfaces,' says Erik Maikranz, who carried out the Monte Carlo simulations as part of his doctoral research work.

Due to the different shapes of the force-distance curves, the physicists suppose that on a hydrophilic surface fewer cell wall proteins are involved in the binding process because these molecules first have to overcome a potential barrier, which effectively reduces the number of protein macromolecules that can tether the cell to the surface. 'The potential barrier to adhesion on hydrophilic surfaces is relatively high, so only a few of the cell wall proteins are able to overcome this energy barrier in a particular time. On hydrophobic surfaces, however, the barrier is negligibly small, so that many cell wall proteins can adhere directly to the surface,' explains Dr. Christian Spengler, who performed the experiments in the study.

PITTSBURGH, Sept. 16, 2020 - People with one of the most common heart disorders who are exposed to greater levels of pollution have a 1.2-fold higher risk of stroke than their peers who live with less pollution, according to a JAMA Network Open study published recently by researchers at the UPMC Heart and Vascular Institute and University of Pittsburgh School of Medicine.

The study is the largest of its kind to include neighborhood-specific pollution data--rather than simply hospitalization data--and further emphasizes the importance of air pollution alerts in advising the activities of people with certain heart conditions.

"We measured pollution exposure at people's doorsteps by using geocoding and then determined their annual exposure to particulate matter. This approach and the sample size make our study particularly powerful," said Jared W. Magnani, M.D., M.Sc., UPMC cardiologist and associate professor of medicine at Pitt. "We can use this information to guide our patients by advising them to limit exposure to pollution. For example, we can notify those with atrial fibrillation to avoid being outside on days with unhealthy air quality, which may reduce their risk of stroke."

Magnani and his colleagues followed more than 31,000 people living in Allegheny County since 2007 with atrial fibrillation (AFib), a common heart rhythm disorder affecting at least 2.7 million Americans. Using suitcase-sized air pollution monitors mounted on telephone poles, the team was able to measure the exact levels of fine particulate pollution--soot--that the participants were breathing on a daily basis. The Pittsburgh region is ranked by the American Lung Association as one of the 10 most polluted in the U.S.

The researchers found that stroke risk steadily increased with higher daily exposure to air pollution. People with AFib already are at five times the risk of stroke, so the additional risk posed by fine particulate pollution is particularly concerning, Magnani noted.

"Our results advance the understanding of how air pollution impacts public health and strengthens the argument for continued advocacy to curb pollution," he said. "Fine particulate pollution is very small--it is able to get into our bodies through our lungs and into our blood stream where it can trigger heart events."

The team went on to examine the impact of pollution on different demographic and socioeconomic groups. They found that fine particulate exposure is 1.5-fold higher in blacks compared to whites, and 1.3-fold higher in those living below poverty versus above.

"Pollution exposure correlates with socioeconomic position, as people living closer to industrial sources tend to be lower income and minoritized. Hence, air pollution worsens racial disparities in health outcomes, due to the increased residential exposure," Magnani said. "Our study indicates the importance of modifying pollution as a risk factor for adverse health outcomes."

Magnani said future research will explore how individual factors--such as physical activity, diet, health care access and medication--might interact with pollution levels to modify stroke risk for people with AFib.

Overall, scientists from 24 countries and regions contributed, including the United Kingdom, Saudi Arabia, the Netherlands, the United States, Greece, Germany, Brazil, Pakistan, Malaysia, Australia, Argentina, Georgia, Romania, Armenia, Chile, China (with Hong Kong as a separate participant), Turkey, Italy, and Mexico. Overall, 5,320 students have been polled. Associate Professor of the KFU's Department of Pedagogical Psychology Olga Lopukhova was one of the participants.

"It's well established that men and women differ in their self-perception, values, and personality traits, as well as stereotypes held with regards to representatives of one or the other sex," she explains. "Men typically find themselves more active, whereas women think of themselves as more sociable. The paper pays attention to how such effects differ between cultural groups with the focus on self-construal and depressive symptoms."

It turns out that women are more depressive, especially in societies with low gender equality rankings. Furthermore, the research showed a slightly different picture of sex differences in self-assessment among students than could be inferred from previous such polls.

"In all sampling groups, we cannot find proof of sex differences in a culture as a whole. Instead, we can see that women see themselves as more interdependent in the conditions of low gender equality and more independent in high gender equality. Men self-assess as more closed, whereas women feel more connected with others. There are no noticeable sex differences in the other two parameters of self-construal or in depressive symptoms," continues the interviewee.

In the Russian version, the researchers added the interaction of the congruence of students to the culture type and their inclusion into social groups with their psychological wellbeing.

"The problem of psychological wellbeing and its factors becomes more and more popular in Russian and overseas research in light of the ever complicating conditions of personality adaptation to the fast-changing values, social norms, types of behavior, and interaction," says Lopukhova. "Students are such a social group prone to the risks psychological non-wellbeing because of age factors, their changing social standing, and exposedness to adaptation and information overloads."

Becoming is a student is often inextricably linked with a change in cultural environment, be it moving to another country or city or moving from countryside to an urban dwelling. In any case, a student needs to go through adaptation and acculturation processes while starting their studies.

The Kazanian part of the poll comprised 488 respondents, 249 of whom were female and 239 male, aged from 18 to 28 years, from various universities of the city. The results showed that students with median congruence-to-culture ratios showed better psychological wellbeing. About a third of students had pronounced depressive symptoms and unsteady self-esteem, which calls for more attention to psychological support.

As KFU researchers found, the congruence (internally non-contradictory acceptance) of the normative values of the cultural environment is a cultural predictor of subjective wellbeing. Conversely, non-congruence, i. e. non-acceptance of behavioral norms, is a predictor of non-wellbeing and heightened depressive symptoms. Inclusion in social groups is also a predictor.

Overall, the presence of depressive symptoms is highly dependent on cultural congruence, whereas self-esteem is not.

When we talk of Nordic history, it is all but impossible not to mention the Vikings. Stories about the Scandinavian warriors and their Old Norse Gods have long since travelled all around the world. But perhaps part of that narrative is only based on myths and brought to life by popular culture. At least, this is what is indicated by a new study from the University of Copenhagen.

The study is the biggest genetic study of Vikings ever. The researchers have sequenced the genome of 442 bone fragments from the Viking Age, from all over Europe, and they have made some rather surprising discoveries. Among other things, the Vikings may not be quite as Nordic as hitherto believed.

"The Vikings had a lot more genes from Southern and Eastern Europe than we anticipated. They frequently had children with people from other parts of the world. In fact, they also tend to be dark-haired rather than blond, which is otherwise consider an established Viking-trait," Professor at Lundbeck Foundation Center for Geogenetics at the GLOBE Institute at the University of Copenhagen, Eske Willerslev, explains.

Peasants missed out on the Bronze Age

The new study also reveals that generally Vikings were a lot more genetically diverse than the peasant societies on the Scandinavian mainland.
"The Vikings lived in coastal areas, and genetically speaking, they were an entirely different people to the peasant societies living further inland. The mainland inhabitants had a lot less in common with the Vikings than the peasants who lived in Europe thousands of years ago. You could almost say that genetically speaking, the peasants missed out on the entire Iron and Bronze Age," co-author of the study and Assistant Professor at the Center For Geogenetics at the GLOBE Institute, Ashot Margaryan explains.

However, the Viking's diverse genome stems not merely from people from elsewhere travelling to their settlements. In fact, they were themselves avid travellers, and historically, we know them best for their plundering and murdering raids abroad. But this genetic study sheds new light on who went where.

"The Danish Vikings went to England, while the Swedish Vikings went to the Baltic and the Norwegian Vikings went to Ireland, Iceland and Greenland. However, the Vikings from these three 'nations' only very rarely mixed genetically. Perhaps they were enemies or perhaps there is some other valid explanation. We just don't know," Ashot Margaryan says.

A Viking on the outside, a Scotsman on the inside

The new study also discards what we think we know about who actually went on raids together. Researchers have been able to find out more about this at a gravesite in Estonia, where raiding Vikings were brutally murdered.

"Popular culture suggests that the Viking Chief would recruit the strongest warriors from neighbouring tribes or communities to join him on a raid somewhere. But at least five of the Vikings in this grave are closely related. So perhaps you just brought your family along when you went on a raid," Eske Willerslev explains.

Vikings were not always murdered though; they fared better in other places. In England, by way of example, it has been possible to trace an influx of people from Scandinavia by studying language and specific place names. And the new study shows that in some of those places, the inhabitants actually embraced the entire Viking culture.

"In Scotland there's a grave, which in archaeological terms would be classified as a Viking grave. Its swords and symbols reflect the Viking culture. However, genetically speaking, the man in the grave has nothing in common with the Vikings. He is an example of how the Viking culture was embraced in certain places," Eske Willerslev elaborates.

And the new study not only discards popular ideas about Vikings, from time to time, scientific circles have also discussed the Viking Age.

"Some researchers and intellectuals have been of the opinion that in the North, we have a tendency to romanticize the Viking Age, because it is our own, and a very specific history. They have argued that the Viking Age wasn't really an Age at all, but rather part of the Iron Age. However, with this new study we're able to establish that the Viking Age was indeed something special. The Vikings travelled much farther, had lots of Southern European genes and were very likely part of a much more extensive cultural exchange with the rest of the world than any contemporary peasant society," Eske Willerslev concludes.

Researchers at Trinity College Dublin have examined the sustainability of different models of the most commonly used oral health product - the toothbrush - to ascertain which is best for the planet and associated human health.

Although the toothbrush is a widely recommended healthcare device worldwide, there is currently little quantitative data available for its impact on the planet. The research study, in collaboration with Eastman Dental Institute at University College London, is published in the British Dental Journal today (Tuesday, 15th September 2020). It represents the first time a life-cycle assessment (LCA) has been used to measure environmental consequences of a healthcare product.

Healthcare is a major emitter of environmental pollutants that adversely affect health, but awareness of these effects remains low both in the industry and in the general consumer population. There is currently little evidence or guidance regarding the sustainability of specific healthcare interventions, services or devices.

Researchers considered different manufacturing models of the toothbrush and measured the environmental impact (carbon footprint) and human health impact (DALYS) of the toothbrush. The electric toothbrush, the standard plastic brush, the plastic brush with replaceable head, and the bamboo brush were used. The team found that the electric toothbrush was comparatively harmful for planetary health.

The findings highlight the human health burden of the toothbrush manufacturing process. The electric toothbrush causes 10 hours of disability measured in Disability-Adjusted Life years or DALYS mainly for the people associated with the process of making and producing the devices. This is five times higher than a normal plastic brush.

The team found that the most environmentally sustainable toothbrush was not bamboo, as could perhaps be popularly believed, but a hypothetical continually recycled plastic toothbrush.

This simple comparative LCA showed that a plastic manual replaceable head toothbrush and bamboo manual toothbrush perform better than traditional plastic manual and electric toothbrushes in every environmental impact outcome measure used in this study. These results could be used to inform individual consumer choice, oral health recommendations, procurement of toothbrushes for public health programmes, and toothbrush manufacturers. Using LCA to inform healthcare policies and recommendations will help healthcare providers move towards a more environmentally sustainable system.

Dr Brett Duane, Associate Professor in Public Dental Health at Trinity College and lead researcher said:

" There are billions of toothbrushes used and discarded every year. Our research shows that electric toothbrushes are actually harmful for the planet and to the people involved in the manufacturing process and distribution. There is not a lot of evidence to show they are more effective unless you struggle to clean your teeth with a normal toothbrush. We have also shown bamboo toothbrushes are not the answer. Using them just stops land from being put to better use such as helping biodiversity, or in growing forests to offset carbon emissions.

The ideal toothbrush is one which uses plastic which is recycled in a continuous process. Plastic brushes which can be recycled don't take up a lot of land and they don't need lots of water to grow. The important thing here is to keep the plastic in the recycling chain. We need a system where plastic toothbrushes can be collected like batteries and then recycled into new products. If the plastic escapes the recycling chain, it needs to be able to be easily and naturally broken down into harmless products.

Manufacturers, consumers, health professionals, and health policy makers should consider environmental sustainability as well as money and people's health when recommending products. Governments and industry should consider how they could support recycling programmes. More funding is also required to support sustainability research in this area."

3D printing has driven innovations in fields ranging from art to aerospace to medicine. However, the high-energy ultraviolet (UV) light used in most 3D printers to cure liquid resins into solid objects limits the technique's applications. Visible-light curing, which would be more appropriate for some uses, such as tissue engineering and soft robotics, is slow. Now, researchers reporting in ACS Central Science have developed photopolymer resins that boost the speed of visible-light curing.

With the help of computer-aided design, 3D-printed objects are made by the successive layering of a material into a 3D shape, with each layer solidified or "cured" using UV light. Being able to use visible light for curing would have advantages, including reduced cost, improved biocompatibility, greater depth of light penetration and reduced light scattering. These attributes could open up new applications for 3D printing, such as making opaque composites, multi-material structures or hydrogels containing live cells. However, because visible light is lower in energy than UV, visible-light curing is currently too slow to be practical. Zachariah Page and colleagues wanted to find a way to speed up the process.

The researchers developed violet-, blue-, green- and red-colored resins that contained a monomer, a photoredox catalyst (PRC), two co-initiators and an opaquing agent. When the PRC absorbed visible light from LEDs, it catalyzed the transfer of electrons between the co-initiators, which generated radicals that caused the monomer to polymerize. The opaquing agent helped confine curing to the areas struck by light, which improved spatial resolution. The optimized mix of components allowed the researchers to print stiff and soft objects with small features (less than 100 μm), mechanical uniformity and build speeds up to 1.8 inches per hour. Although the best build speed is still less than half that of the fastest rate obtained using UV light, it could be further improved by increasing the light intensity or adding other components to the resin, the researchers say.

The authors acknowledge funding from the U.S. Department of Defense and the Welch Foundation.

The article that accompanies this paper is freely available as an ACS AuthorChoice article here.

The American Chemical Society (ACS) is a nonprofit organization chartered by the U.S. Congress. ACS' mission is to advance the broader chemistry enterprise and its practitioners for the benefit of Earth and its people. The Society is a global leader in providing access to chemistry-related information and research through its multiple research solutions, peer-reviewed journals, scientific conferences, eBooks and weekly news periodical Chemical & Engineering News. ACS journals are among the most cited, most trusted and most read within the scientific literature; however, ACS itself does not conduct chemical research. As a specialist in scientific information solutions (including SciFinder® and STN®), its CAS division powers global research, discovery and innovation. ACS' main offices are in Washington, D.C., and Columbus, Ohio.
 

To automatically receive news releases from the American Chemical Society, contact newsroom@acs.org.
 

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E-cigarette, or vaping, associated lung injury (EVALI) has sickened thousands of people, most under the age of 35. Studies have linked vitamin E acetate, an oily substance in some vaping liquids, to the disorder. Now, researchers reporting in ACS' Chemical Research in Toxicology have uncovered a possible mechanism: Vitamin E acetate could increase the fluidity of lung surfactant, causing the surfactant layer to collapse, contributing to symptoms such as shortness of breath and lung inflammation.

The lungs are made up of alveoli, which are tiny cavities where gas exchange takes place. Oxygen that is breathed in diffuses across the alveolar membrane and into the capillaries, while carbon dioxide passes in the opposite direction to be exhaled. Lung surfactant, a fluid made up of lipids and proteins, coats the inner surface of the alveoli, reducing the surface tension so that the alveoli can easily inflate when someone inhales. Scientists still don't know exactly how the surfactant layer expands and contracts when a person breathes in and out, but one hypothesis is that certain lipids get "squeezed out" or expelled when the alveoli contract, and then spread across the surface again when the alveoli expand. Drew Marquardt and colleagues wondered how vitamin E acetate, which has been found in the lungs of most EVALI patients but not in healthy controls, could influence this process.

To find out, the researchers added increasing amounts of vitamin E acetate to two model lung surfactants in the lab: one containing only the lipid DPPC (the primary component of lung surfactant), and the other containing a mixture of the four major lipids in the fluid. Using a combination of neutron spin echo and small-angle neutron scattering, the team found that increasing vitamin E acetate concentration increased membrane fluidity and compressibility for both model surfactants, up to a plateau. These findings suggest that, in the presence of the vaping additive, the lung surfactant monolayer could "squeeze out" lipids prematurely during exhalation, thereby becoming unstable. However, the researchers note that these experiments were conducted in a model system without protein components or alveoli, so more work still needs to be done.

The authors acknowledge funding from the Natural Sciences and Engineering Research Council of Canada, the Ontario Graduate Scholarship program, the National Institute of Standards and Technology, the Center for High Resolution Neutron Scattering, the National Science Foundation, the WE-SPARK Health Institute and the University of Windsor.

The abstract that accompanies this paper is available here.

The American Chemical Society (ACS) is a nonprofit organization chartered by the U.S. Congress. ACS' mission is to advance the broader chemistry enterprise and its practitioners for the benefit of Earth and its people. The Society is a global leader in providing access to chemistry-related information and research through its multiple research solutions, peer-reviewed journals, scientific conferences, eBooks and weekly news periodical Chemical & Engineering News. ACS journals are among the most cited, most trusted and most read within the scientific literature; however, ACS itself does not conduct chemical research. As a specialist in scientific information solutions (including SciFinder® and STN®), its CAS division powers global research, discovery and innovation. ACS' main offices are in Washington, D.C., and Columbus, Ohio.
 

To automatically receive news releases from the American Chemical Society, contact newsroom@acs.org.
 

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The most basic activity of a living thing is to turn one copy of its genome into two copies, crafting one cell into two. That replication event begins with a set of proteins--the Origin Recognition Complex (ORC). And, with some cancers and developmental diseases linked to ORC proteins, structural biologists need to see how the complex works so they can understand how it might go wrong. Cold Spring Harbor Laboratory (CSHL) Professor & HHMI Investigator Leemor Joshua-Tor and colleagues published images of the human ORC in exquisite detail in eLife, showing how it changes shapes in dramatic ways as it assembles around DNA.

The scientists think the first piece of the complex--ORC1--finds the stretch of DNA where replication is supposed to begin and assembles the rest of the ORC (subunits 2-5) at that spot. Though, in yeast, a single sequence of DNA peppered throughout the genome spells out "start," there are no such simple signposts for the 30,000 start sites in humans. Our start signals are mysterious. Joshua-Tor says:

"When the cell has to duplicate, the first thing that has to happen is that the genome has to duplicate. And so the positioning of ORC on these so-called "start" sites is really the first event that has to happen in order to start the duplication of the genome. You know in bacteria, there's usually one start site because it's a small genome, but in larger organisms like humans, in order to be able to replicate such a large genome, what the cell does is uses many, many start sites. And the interesting thing in mammalian systems is that we actually don't understand what a start site really looks like."

To complicate things further, earlier on, as researchers looked at different organisms, they found differently shaped ORCs. But Joshua-Tor and colleagues found an explanation for those varying shapes. Parts of the ORC twist and pinch in dramatic ways, depending on what they are doing at the moment. A yeast ORC freezes mostly into one stable shape and a fly ORC into another. According to Kin On, a CSHL staff scientist, "the yeast complex is so stable, it is rock solid. But the human ORC assembly is very dynamic." Using cryo-electron microscopy (cryo-EM), sample preparation, and computer analysis techniques, the group was able to catch the human enzyme complex in many different shapes, including one that looks like a fly ORC and another that looks like yeast ORC. They assembled a series of images into a movie showing a wide range of motions. They even caught the first snapshot of a human ORC straddling a DNA molecule, which is key to understanding how ORCs do their jobs. According to Matt Jaremko, a postdoctoral fellow in Joshua-Tor's lab, "ORC is flexible, which helps the protein interact with DNA."

The ORC was discovered at CSHL in 1992 by CSHL President and CEO Bruce Stillman, a collaborator of Joshua-Tor's on this study.

Though a better understanding of ORCs may point to better treatments for cancer and developmental syndromes, Joshua-Tor says there is another reason to want to learn what we can about these beautiful cellular machines:

"How we duplicate our genome is the most basic process of life, right? Really that's what life is all about. So, regardless of how we understand cancer and this developmental syndrome, you know, understanding ourselves and understanding the most basic process, that is part of the human endeavor really to understand ourselves. So it's not all about the utility of it. It's really, y'know, one of the basic endeavors of, of humanity is trying to understand life and ourselves. I think it's a big part of why we're doing it. At least a big part of why I'm doing it."

Higher viral loads are associated with a greater risk of death among cancer and non-cancer patients hospitalized with coronavirus disease 2019 (COVID-19), researchers report September 15 in the journal Cancer Cell. Among hospitalized COVID-19 patients, those with hematologic malignancies who had recently been treated for cancer had the highest levels of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes COVID-19.

"As a community, we've only begun to understand the relationship between SARS-CoV-2 viral load and outcomes," says senior study author Michael Satlin, an assistant professor of medicine in the Division of Infectious Diseases at Weill Cornell Medicine and an assistant attending physician at NewYork-Presbyterian/Weill Cornell Medical Center. "Currently, this quantitative information is not given to patient care teams, and providers only know if a patient's test is positive or negative. Giving this information to providers of patients with cancer who have COVID-19 could help them decide on which patients should receive more intensive monitoring when they are in the hospital and which should receive new antiviral medicines if these treatments are in short supply."

Worldwide, COVID-19 has affected more than 27 million people and has resulted in approximately 900,000 deaths. Initial reports have suggested that patients with cancer may be more likely to develop severe COVID-19 than patients without cancer. Satlin and his collaborators previously found that high SARS-CoV-2 viral load upon presentation to the emergency department is associated with in-hospital mortality among the general inpatient population. But until now, it was not clear how admission viral load may affect the clinical outcomes of hospitalized patients who have both cancer and COVID-19.

In the new study, Satlin and his team used two standard diagnostic tests to measure the amount of SARS-CoV-2 in nasopharyngeal swab specimens obtained upon admission to three New York City hospitals between March 15 and May 14, 2020. One hundred of the patients had active cancer, and 2,914 patients did not. Among the cancer patients, some had solid tumors, whereas others had hematologic malignancies, which affect blood, blood cell-producing tissue called bone marrow, and lymph nodes - organs making up part of the circulatory and immune systems.

Half of patients with hematologic malignancies had high viral loads, compared to approximately 30% of patients without cancer. Among patients with hematologic malignancies, only those who had received chemotherapy or targeted therapy during the previous six months had significantly higher viral loads than the general inpatient population with COVID-19.

"We suspect that this finding may be from the underlying immunodeficiencies conferred by either the hematologic malignancies or the administered therapies, which may decrease the ability to inhibit proliferation of SARS-CoV-2," says co-first author Lars Westblade, an associate professor of pathology and laboratory medicine at Weill Cornell Medicine and a clinical microbiologist at NewYork-Presbyterian/Weill Cornell Medical Center. "Additional studies with a larger sample size of patients with hematologic malignancies are needed to more definitely assess whether these patients have increased mortality when hospitalized with COVID-19."

Overall, the in-hospital mortality rate was 38.8% among patients with a high viral load, 24.1% among patients with a medium viral load, and 15.3% among patients with a low viral load. Cancer patients showed a similar pattern, with mortality rates of 45.2%, 28.0%, and 12.1%, respectively. High viral loads in patients with cancer were associated with increased in-hospital mortality than low viral loads. This finding remained statistically significant, even after adjusting for factors such as age and need for supplemental oxygen within three hours of presentation to the emergency department.

One important caveat is that it is not clear whether viral load predicts mortality rate in non-hospitalized individuals with COVID-19. "We encourage subsequent studies to assess the potential role of using SARS-CoV-2 viral load to guide care for outpatients with and without cancer," says co-first author Gagandeep Brar, an assistant professor of medicine in the Division of Hematology and Medical Oncology at Weill Cornell Medicine and an assistant attending physician at NewYork-Presbyterian/Weill Cornell Medical Center.

For their own part, the researchers plan to conduct larger studies to confirm their findings and investigate whether specific types of cancer and cancer treatments lead to higher viral loads and worse outcomes. They would also like to assess whether measuring viral loads over time in a given patient could be used to personalize the type and duration of therapy.

The culture of science is changing. Researchers are examining the methods and practices that have long been the basis for scientific research and publication with the goal of improving it. This "moment of change," the authors of a new paper write, presents an opportunity to address science's "historic lack of diversity and noninclusive culture."

For the paper, the authors examined the two paths that scientists are following: the movement for reproducibility and the movement for open science. Both movements aim to create centralized archives for data, computer code and other resources, but from there, the paths diverge. The movement for reproducibility calls on scientists to reproduce the results of past experiments to verify earlier results, while open science calls on scientists to share resources so that future research can build on what has been done, ask new questions and advance science.

The international research team, led by Indiana University (IU), finds the two movements do more than diverge. They have very distinct cultures, with two distinct literatures produced by two groups of researchers with little crossover. Their investigation also suggests that one of the movements -- open science -- promotes greater equity, diversity, and inclusivity. Their findings were reported earlier this week in a paper titled "Open science, communal culture, and women's participation in the movement to improve science," published in the Proceedings for the National Academy of Sciences.

The team's analysis of academic papers published from 2010-2017 identified with one of the two movements showed that even though both movements span widely across STEM fields, the authors within them occupy two largely distinct networks. The researchers also analyzed abstracts of the papers to determine the values implicit in the language used to define the research. Specifically, they looked at the degree to which the research was prosocial, that is, oriented toward helping others by seeking to solve large social problems.

With respect to gender, the team found that "women publish more often in high-status authorship positions in open science, and that participation in high-status authorship positions has been increasing over time in open science, while in reproducibility women's participation in high-status authorship positions is decreasing over time," according to Mary Murphy, a professor at IU and a lead author on the study.

With a core of eight lead scientists at IU, the team also included 20 more co-authors, mostly women and people of color who are experts on how to increase the participation of underrepresented groups in science; diversity and inclusion; and the movements to improve science. Among them is Valerie Jones Taylor, a faculty member in Lehigh University's Department of Psychology with a joint appointment in Africana Studies. Taylor investigates how stereotyping and prejudice affect the academic performance of underrepresented groups, interracial interactions, and the treatment of racialized physical spaces. Her work also examines ways to improve interracial encounters in academic and social contexts using virtual reality.

"Research practices that seek to improve the quality of scientific research and knowledge can benefit from what we have learned about the communal, collaborative, and prosocial ideals that mark the open science literature," says Taylor about the study. "Overall, women hold more prominent roles and participate more frequently in scientific research in the open science than the reproducibility literature. This work suggests that the prosocial norms in the open science movement encourage greater diversity and inclusion, which benefits scientific knowledge."

This study intersects with Taylor's interests in that it seeks to understand how research practices in science - a domain that can reinforce negative gender and racial stereotypes and be unwelcoming to members from underrepresented groups - can foster a more inclusive and collaborative culture.

Taylor believes that the study results "...should encourage researchers across scientific disciplines to adopt the communal and prosocial practices of the open science movement to spur constructive criticism, rigor, and innovation while promoting norms that foster scientific environments that are more welcoming and comfortable for all."

UTICA, NY -- Researchers from the Masonic Medical Research Institute (MMRI), the Precision Cardiology Lab (PCL) of the Broad Institute at MIT and Harvard, Bayer USA, Massachusetts General Hospital, and University of Pennsylvania collaborated to uncover some pressing questions about the biology of the heart. While understanding the mechanisms causal to human heart disease remain active areas of research for many scientists, important knowledge gaps about its composition and function remain unknown.

The current study, "Transcriptional and Cellular Diversity of the Human Heart," published on August 4th in the journal Circulation, sought to uncover how many different cell types comprise the heart, how each cell type differs between various regions of the heart, and how the differences relate to genetic risk and affect cardiac health. The team applied state-of-the-art approaches to identify these previously unknown signatures and created a map of the nearly 300,000 identified cells in human hearts.

Ultimately, this study increases scientists' understanding of the human heart, enabling a greater understanding of and treatments for cardiac disease. "Understanding of human cardiac biology at this resolution was not possible just a few years ago," said Dr. Nathan Tucker, Assistant Professor at MMRI and first author of the study. "We are proud of the strong collaborative effort that was required to make this important observation a reality and are excited to see where it goes and the effect it has in the near future."

The results should also serve as a resource to scientists around the world. "One of our major aims was to create a public resource to share with our research community," Tucker noted, "We are very excited to see how this facilitates studies by other groups, both as a data source for further analysis and as a roadmap for complementary work." For more information, please visit: broadinstitute.org/news/single-cell-map-heart-reveals-wide-cellular-diversity.

ITHACA, N.Y. - When stars like our sun die, all that remains is an exposed core - a white dwarf. A planet orbiting a white dwarf presents a promising opportunity to determine if life can survive the death of its star, according to Cornell University researchers.

In a study published in the Astrophysical Journal Letters, they show how NASA's upcoming James Webb Space Telescope could find signatures of life on Earth-like planets orbiting white dwarfs.

A planet orbiting a small star produces strong atmospheric signals when it passes in front, or "transits," its host star. White dwarfs push this to the extreme: They are 100 times smaller than our sun, almost as small as Earth, affording astronomers a rare opportunity to characterize rocky planets.

"If rocky planets exist around white dwarfs, we could spot signs of life on them in the next few years," said corresponding author Lisa Kaltenegger, associate professor of astronomy in the College of Arts and Sciences and director of the Carl Sagan Institute.

Co-lead author Ryan MacDonald, a research associate at the institute, said the James Webb Space Telescope, scheduled to launch in October 2021, is uniquely placed to find signatures of life on rocky exoplanets.

"When observing Earth-like planets orbiting white dwarfs, the James Webb Space Telescope can detect water and carbon dioxide within a matter of hours," MacDonald said. "Two days of observing time with this powerful telescope would allow the discovery of biosignature gases, such as ozone and methane."

The discovery of the first transiting giant planet orbiting a white dwarf (WD 1856+534b), announced in a separate paper - led by co-author Andrew Vanderburg, assistant professor at the University of Wisconsin, Madison - proves the existence of planets around white dwarfs. Kaltenegger is a co-author on this paper, as well.

This planet is a gas giant and therefore not able to sustain life. But its existence suggests that smaller rocky planets, which could sustain life, could also exist in the habitable zones of white dwarfs.

"We know now that giant planets can exist around white dwarfs, and evidence stretches back over 100 years showing rocky material polluting light from white dwarfs. There are certainly small rocks in white dwarf systems," MacDonald said. "It's a logical leap to imagine a rocky planet like the Earth orbiting a white dwarf."

The researchers combined state-of-the-art analysis techniques routinely used to detect gases in giant exoplanet atmospheres with the Hubble Space Telescope with model atmospheres of white dwarf planets from previous Cornell research.

NASA's Transiting Exoplanet Survey Satellite is now looking for such rocky planets around white dwarfs. If and when one of these worlds is found, Kaltenegger and her team have developed the models and tools to identify signs of life in the planet's atmosphere. The Webb telescope could soon begin this search.

The implications of finding signatures of life on a planet orbiting a white dwarf are profound, Kaltenegger said. Most stars, including our sun, will one day end up as white dwarfs.

"What if the death of the star is not the end for life?" she said. "Could life go on, even once our sun has died? Signs of life on planets orbiting white dwarfs would not only show the incredible tenacity of life, but perhaps also a glimpse into our future."

New University of Colorado Boulder-led research finds that the traits that make vertebrates distinct from invertebrates were made possible by the emergence of a new set of genes 500 million years ago, documenting an important episode in evolution where new genes played a significant role in the evolution of novel traits in vertebrates.

The findings, published today in Nature, show that a gene family only found in vertebrates is critical for forming the head skeleton and other traits unique to them during embryonic development.

"Every animal essentially has the same basic core set of Lego pieces to make them. What this paper shows is that vertebrates have a few special pieces in addition to that, and we identify those special pieces," said Daniel Medeiros, senior author of the paper and associate professor of ecology and evolutionary biology.

These special pieces in vertebrates are known as the Endothelin signaling pathway, a set of genes that influence how cells talk to each other. The researchers found this gene family is responsible for allowing neural crest cells--cells that develop into unique vertebrate traits like skeletal parts, pigment cells and our peripheral nervous system--to proliferate and specialize into different roles throughout the body.

Evolutionary theories have given weight to the role of genome duplication in the evolution of new traits, and for good reason. When a genome duplicates, new copies of existing genes can take on new roles in an organism. But since previous ideas were based mostly on observation, Medeiros wanted to test if gene duplication could have allowed vertebrates to become so special, or if the appearance of brand new genes could have played a role.

Medeiros and his colleagues tested the hypothesis that new gene families could also give rise to new traits by genetically modifying the larvae of sea lamprey, a type of jawless fish, through identifying and removing this specific gene family. If their prediction was correct, removing it would revert a sea lamprey during its larval development into a more invertebrate-like worm, a close evolutionary ancestor.

"And we found that by knocking out this new gene family, you can almost erase most of the key vertebrate traits that make vertebrates special," said Medeiros.

While gene duplication is still an important part of the evolutionary process--as this new gene family is also duplicated in vertebrates--they found that duplication was not as critical in giving rise to the special neural crest cell types that vertebrates evolved as was the emergence of this new gene family.

This finding is significant in part because it's rare to find clear roles for genes that are unique to vertebrates, said lead author Tyler Square, who recently completed his PhD in the Medeiros lab and is now at the University of California Berkeley.

"We thought that gene duplication was the most important thing. But here, we found both of those things [new genes and duplications] happening at once," said Square.

Reverse engineering the first fish

Fish were the first vertebrates, from which all others evolved--including humans. But there is a gap in the fossil record right when the first fish were evolving, because they had little, soft skeletons which were not preserved in the fossil record.

So how can scientists work out where the first fish came from, and therefore how all vertebrates came to be?

"Rather than looking at fossils, we use tools like molecular biology and genetics to try to understand how evolution has happened, kind of like genetic paleontology," said Medeiros. "In the deepest molecular genetic terms, we're trying to reverse engineer how a creature evolves. It's the closest you can get to Jurassic Park."

The creature they chose to reverse engineer, however, might seem a bit monstrous.

"While most people think of a big ugly hurricane of teeth sticking on to fish and chewing on them, sea lamprey are surprisingly cute when they're little baby larvae," said Square.

The sea lamprey, a jawless fish, diverged in evolution from other fish 500 million years ago. Because they hold onto several older vertebrate features, this gives the researchers the best snapshot of the early stage of vertebrate evolution with a living organism today.

"A lamprey and a human are extremely different. But by doing these kinds of studies, we can know what makes them the same," said Square. "This is stuff that's really fundamental, not just to mammals and humans, but to every vertebrate that exists."

Square and his colleagues used the gene-editing tool CRISPR during its early days to find out how important this new gene family is to making vertebrates, well, vertebrates.

"It was the wild west of CRISPR days," said Square. "But we couldn't have done this whatsoever if it weren't for CRISPR."

Not only did this technology allow the researchers to test hypotheses functionally, by knocking out genes, but they were also the first team to use CRISPR in sea lampreys. Previously, this technology had only been used in some vertebrates like mice, frogs and zebrafish.

"And that's a really narrow view of life on the planet," said Medeiros. "What CRISPR has done is democratized genetic studies across diverse organisms. It's super powerful for answering evolutionary questions."

WASHINGTON -- Researchers have developed an advanced spectrometer that can acquire data with exceptionally high speed. The new spectrometer could be useful for a variety of applications including remote sensing, real-time biological imaging and machine vision.

Spectrometers measure the color of light absorbed or emitted from a substance. However, using such systems for complex and detailed measurement typically requires long data acquisition times.

"Our new system can measure a spectrum in mere microseconds," said research team leader Scott B. Papp from the National Institute of Standards and Technology and the University of Colorado, Boulder. "This means it could be used for chemical studies in the dynamic environment of power plants or jet engines, for quality control of pharmaceuticals or semiconductors flying by on a production line, or for video imaging of biological samples."

In The Optical Society (OSA) journal Optics Express, lead author David R. Carlson and colleagues Daniel D. Hickstein and Papp report the first dual-comb spectrometer with a pulse repetition rate of 10 gigahertz. They demonstrate it by carrying out spectroscopy experiments on pressurized gases and semiconductor wafers.

"Frequency combs are already known to be useful for spectroscopy," said Carlson. "Our research is focused on building new, high-speed frequency combs that can make a spectrometer that operates hundreds of times faster than current technologies."

Getting data faster

Dual-comb spectroscopy uses two optical sources, known as optical frequency combs that emit a spectrum of colors - or frequencies - perfectly spaced like the teeth on a comb. Frequency combs are useful for spectroscopy because they provide access to a wide range of colors that can be used to distinguish various substances.

To create a dual-comb spectroscopy system with extremely fast acquisition and a wide range of colors, the researchers brought together techniques from several different disciplines, including nanofabrication, microwave electronics, spectroscopy and microscopy.

The frequency combs in the new system use an optical modulator driven by an electronic signal to carve a continuous laser beam into a sequence of very short pulses. These pulses of light pass through nanophotonic nonlinear waveguides on a microchip, which generates many colors of light simultaneously. This multi-color output, known as a supercontinuum, can then be used to make precise spectroscopy measurements of solids, liquids and gases.

The chip-based nanophotonic nonlinear waveguides were a key component in this new system. These channels confine light within structures that are a centimeter long but only nanometers wide. Their small size and low light losses combined with the properties of the material they are made from allow them to convert light from one wavelength to another very efficiently to create the supercontinuum.

"The frequency comb source itself is also unique compared to most other dual-comb systems because it is generated by carving a continuous laser beam into pulses with an electro-optic modulator," said Carlson. "This means the reliability and tunability of the laser can be exceptionally high across a wide range of operating conditions, an important feature when looking at future applications outside of a laboratory environment."

Analyzing gases and solids

To demonstrate the versatility of the new dual-comb spectrometer, the researchers used it to perform linear absorption spectroscopy on gases of different pressure. They also operated it in a slightly different configuration to perform the advanced analytical technique known as nonlinear Raman spectroscopy on semiconductor materials. Nonlinear Raman spectroscopy, which uses pulses of light to characterize the vibrations of molecules in a sample, has not previously been performed using an electro-optic frequency comb.

The high data acquisition speeds that are possible with electro-optic combs operating at gigahertz pulse rates are ideal for making spectroscopy measurements of fast and non-repeatable events.

"It may be possible to analyze and capture the chemical signatures during an explosion or combustion event," said Carlson. "Similarly, in biological imaging the ability to create images in real time of living tissues without requiring chemical labeling would be immensely valuable to biological researchers."

The researchers are now working to improve the system's performance to make it practical for applications like real-time biological imaging and to simplify and shrink the experimental setup so that it could be operated outside of the lab.