Earth

Plant inducible defense starts with the recognition of microbes, which leads to the activation of a complex set of cellular responses. There are many ways to recognize a microbe, and recognition of microbial features by pattern recognition receptors (PRRs) outside the cell was long thought to activate the first line of defense: Pattern Triggered Immunity, or PTI. To avoid these defense responses, microbes of all kinds evolved the ability to deliver effector molecules to the plant cell, either directly into the cytoplasm or into the area just outside the cell, where they are taken up into the cytoplasm. Response to these effector molecules was thought to be mediated exclusively by intracellular nucleotide-binding domain leucine-rich repeat receptors (NLRs) which induce Effector Triggered Immunity, or ETI. These two signaling pathways are often thought of as two distinct branches of the plant immune response, with each contributing differently to overall immunity. However, the dichotomy between PTI and ETI has become blurred due to recent discoveries, indicating that responses to PRR receptor signaling and NLR signaling extensively overlap.

"The two immune branches were previously considered to be separate but increasing evidence in recent years shows that they are intimately connected," explained Kenichi Tsuda, a plant biologist at Huazhong Agricultural University in China. "It is time to re-think the current model."

Over the past year and a half, exciting findings have revealed a much more complex and nuanced picture of plant defense. Tsuda and colleague You Lu, of the University of Minnesota in the United States, collaborated on a review recently published in the MPMI journal. Their goal was to integrate these new ideas with the long-standing model of separate ETI and PTI pathways into a newer, more nuanced model in which the pathways do exist, but with multiple points of interaction between them and in which each pathway is intimately connected.

These ideas are central to our understanding of the interactions between plants and microbes, but also have important implications for agriculture. "These two branches of plant immunity contribute majorly to pathogen resistance," said Tsuda. "Modes of action of the plant immune system is fundamental to any application of our knowledge into practice such as agriculture."

Despite the huge effort from the research community to understand plant defense signaling and the many recent advances, there are still many unknowns in this area. For example, Tsuda says the mechanism of "how NLRs use PRRs is completely unknown." In fact, Lu and Tsuda propose two models that might explain this interaction at a cellular level, one of which involves signaling between cells in a tissue, leading to Tsuda's recommendation for researchers to examine immune responses at the single cell level.

"As many researchers are tackling this question, we will need to update our model on a yearly basis," Tsuda concluded.

On the afternoon of April 13, 2018, a large wave of water surged across Lake Michigan and flooded the shores of the picturesque beach town of Ludington, Michigan, damaging homes and boat docks, and flooding intake pipes. Thanks to a local citizen's photos and other data, NOAA scientists reconstructed the event in models and determined this was the first ever documented meteotsunami in the Great Lakes caused by an atmospheric inertia-gravity wave.

An atmospheric inertia-gravity wave is a wave of air that can run from 6 to 60 miles long that is created when a mass of stable air is displaced by an air mass with significantly different pressure. This sets in motion a wave of air with rising and falling pressure that can influence the water below, as it synchronizes with water movement on the lake's surface like two singers harmonizing.

"That meteotsunami was hands down off the chart awesome," said Debbie Maglothin of Ludington who took photos of the event. "The water in between the breakwaters didn't go down like the water on the outside of them, so it created waterfalls that cascaded over the breakwaters. Had this event occurred during summer it could have washed people right off the breakwaters."

Meteotsunamis generated from this type atmospheric condition are common around the globe, but in the Great Lakes, the few well documented meteotsunamis have been driven by sudden severe thunderstorms where both winds and air pressure changes have played significant roles.

Combining water and weather models

While there are currently no forecast models that effectively predict meteotsunamis in the U.S., new NOAA research based on the Ludington wave demonstrates that existing NOAA numerical weather prediction models and hydrodynamic forecast models may enable scientists to predict these meteotsunami-driving atmospheric waves minutes to hours in advance. The research is published in a special edition of the journal Natural Hazards about meteotsunamis. (https://rdcu.be/b6sNA)

"The good news with this type of meteotsunami is that it is easier to predict than ones triggered by thunderstorms," said Eric Anderson, an oceanographer at NOAA's Great Lakes Environmental Research Laboratory and lead author of the study. "Our short-range weather models can pick up these atmospheric pressure waves, whereas predicting thunderstorms is more difficult."

Meteotsunamis are a lesser known category of tsunami. Unlike the more well known tsunami -- such as the catastrophic 2004 Boxing Day tsunami in Indonesia, which was caused by an earthquake on the seafloor, meteotsunamis are caused by weather, in particular some combination of changing air pressure, strong winds and thunderstorm activity.

"Because the lakes are relatively small, meteotsunamis typically need more than a jump in air pressure to drive them," said Anderson. "That's where the thunderstorms and wind come in to give them a push."

Great Lakes have history of meteotsunamis

Meteotsunamis occur around the world, and are known to occur in the United States primarily on the Great Lakes and along the East and Gulf of Mexico coasts. Meteotsunami waves in the Great Lakes can be particularly insidious because they can bounce off the shoreline and come back again when the skies are clear. They are relatively rare and typically small, the largest producing three to six foot waves, which only occur about once every 10 years.

Predicting these waves in advance would give communities potentially life-saving warnings and would allow residents and businesses to take measures to better protect property. The Ludington meteotsunami resulted in some property damage but no serious injuries. Had the meteotsunami struck in the summer when swimmers, anglers and vacationers flock to the lakeshore beaches, parks and waters, it might have been a different story, as was the case with a meteotsunami that took the lives of eight people in Chicago in June 1954.

"It's a gap in our forecasting," said Anderson. "With this study and other research we are getting closer to being able to predict them in advance."

Boulder, Colo., USA: GSA’s dynamic online journal, Geosphere,
posts articles online regularly. Locations studied this month include the
western Himalaya, the boundary between the southern Coast Ranges and
western Transverse Ranges in California, the northern Sierra Nevada, and
northwest Nepal.

Marine sedimentary records of chemical weathering evolution in the
western Himalaya since 17 Ma

Peng Zhou; Thomas Ireland; Richard W. Murray; Peter D. Clift

Abstract:
The Indus Fan derives sediment from the western Himalaya and Karakoram.
Sediment from International Ocean Discovery Program drill sites in the
eastern part of the fan coupled with data from an industrial well near the
river mouth allow the weathering history of the region since ca. 16 Ma to
be reconstructed. Clay minerals, bulk sediment geochemistry, and magnetic
susceptibility were used to constrain degrees of chemical alteration.
Diffuse reflectance spectroscopy was used to measure the abundance of
moisture-sensitive minerals hematite and goethite. Indus Fan sediment is
more weathered than Bengal Fan material, probably reflecting slow
transport, despite the drier climate, which slows chemical weathering
rates. Some chemical weathering proxies, such as K/Si or kaolinite/(illite
+ chlorite), show no temporal evolution, but illite crystallinity and the
chemical index of alteration do have statistically measurable decreases
over long time periods. Using these proxies, we suggest that sediment
alteration was moderate and then increased from 13 to 11 Ma, remained high
until 9 Ma, and then reduced from that time until 6 Ma in the context of
reduced physical erosion during a time of increasing aridity as tracked by
hematite/goethite values. The poorly defined reducing trend in weathering
intensity is not clearly linked to global cooling and at least partly
reflects regional climate change. Since 6 Ma, weathering has been weak but
variable since a final reduction in alteration state after 3.5 Ma that
correlates with the onset of Northern Hemispheric glaciation. Reduced or
stable chemical weathering at a time of falling sedimentation rates is not
consistent with models for Cenozoic global climate change that invoke
greater Himalayan weathering fluxes drawing down atmospheric CO 2 but are in accord with the idea of greater surface reactivity
to weathering.

View article:

https://pubs.geoscienceworld.org/gsa/geosphere/article-abstract/doi/10.1130/GES02211.1/595660/Marine-sedimentary-records-of-chemical-weathering

Late Pleistocene rates of rock uplift and faulting at the boundary
between the southern Coast Ranges and the western Transverse Ranges in
California from reconstruction and luminescence dating of the Orcutt
Formation

Ian S. McGregor; Nathan W. Onderdonk

Abstract:
The western Transverse Ranges and southern Coast Ranges of California are
lithologically similar but have very different styles and rates of
Quaternary deformation. The western Transverse Ranges are deformed by
west-trending folds and reverse faults with fast rates of Quaternary fault
slip (1–11 mm/yr) and uplift (1–7 mm/yr). The southern Coast Ranges,
however, are primarily deformed by northwest-trending folds and
right-lateral strike-slip faults with much slower slip rates (3 mm/yr or
less) and uplift rates (<1 mm/yr). Faults and folds at the boundary
between these two structural domains exhibit geometric and kinematic
characteristics of both domains, but little is known about the rate of
Quaternary deformation along the boundary. We used a late Pleistocene
sedimentary deposit, the Orcutt Formation, as a marker to characterize
deformation within the boundary zone over the past 120 k.y. The Orcutt
Formation is a fluvial deposit in the Santa Maria Basin that formed during
regional planation by a broad fluvial system that graded into a shoreline
platform at the coast. We used post-infrared–infrared-stimulated
luminescence (pIR-IRSL) dating to determine that the Orcutt Formation was
deposited between 119 ± 8 and 85 ± 6 ka, coincident with oxygen isotope
stages 5e-a paleo–sea-level highstands and regional depositional events.
The deformed Orcutt basal surface closely follows the present-day
topography of the Santa Maria Basin and is folded by northwest-trending
anticlines that are a combination of fault-propagation and
fault-bend-folding controlled by deeper thrust faults. Reconstructions of
the Orcutt basal surface and forward modeling of balanced cross sections
across the study area allowed us to mea­sure rock uplift rates and fault
slip rates. Rock uplift rates at the crests of two major anticlinoria are
0.9–4.9 mm/yr, and the dip-slip rate along the blind fault system that
underlies these folds is 5.6–6.7 mm/yr. These rates are similar to those
reported from the Ventura area to the southeast and indicate that the
relatively high rates of deformation in the western Transverse Ranges are
also present along the northern boundary zone. The deformation style and
rates are consistent with models that attribute shortening across the Santa
Maria Basin to accommodation of clockwise rotation of the western
Transverse Ranges and suggest that rotation has continued into late
Quaternary time.

View article:

https://pubs.geoscienceworld.org/gsa/geosphere/article-abstract/doi/10.1130/GES02274.1/595661/Late-Pleistocene-rates-of-rock-uplift-and-faulting

Influence of pre-existing structure on pluton emplacement and
geomorphology: The Merrimac plutons, northern Sierra Nevada,
California, USA

V.E. Langenheim; J.A. Vazquez; K.M. Schmidt; G. Guglielmo, Jr.; D.S.
Sweetkind

Abstract:
In much of the western Cordillera of North America, the geologic frame­work
of crustal structure generated in the Mesozoic leaves an imprint on later
plutonic emplacement, subsequent structural setting, and present landscape
morphology. The Merrimac plutons in the northern Sierra Nevada (California,
USA) are a good example of the influence of pre-existing structure at a
larger scale. This paper updates and refines earlier studies of the
Merrimac plutons, with the addition of analysis of gravity and magnetic
data and new 206Pb/238U zircon dates. The gravity and
magnetic data not only confirm the presence of two different neighboring
plutons, but also (1) support the presence of a third pluton, (2) refine
the nature of the contact between the Merrimac plutons as being
structurally controlled, and (3) estimate the depth extent of the plutons
to be ~4–5 km. The zircon 206Pb/238U dates indicate
that the two main plutons have statistically different crystallization ages
nearly 4 m.y. apart. Geomorphic analyses, including estimates of relief,
roughness and drainage density and generation of chi plots, indicate that
the two main plutons are characterized by different elevations with large
longitudinal channel knickpoints that we speculatively attribute to
possible reactivation of pre-existing structure in addition to lithologic
variations influencing relative erosion susceptibility in response to prior
accelerated surface uplift.

View article:

https://pubs.geoscienceworld.org/gsa/geosphere/article-abstract/doi/10.1130/GES02281.1/594115/Influence-of-pre-existing-structure-on-pluton

Protolith affiliation and tectonometamorphic evolution of the Gurla
Mandhata core complex, NW Nepal Himalaya

Laurent Godin; Mark Ahenda; Djordje Grujic; Ross Stevenson; John Cottle

Abstract:
Assigning correct protolith to high metamorphic-grade core zone rocks of
large hot orogens is a particularly important challenge to overcome when
attempting to constrain the early stages of orogenic evolution and
paleogeography of lithotectonic units from these orogens. The Gurla
Mandhata core complex in NW Nepal exposes the Himalayan metamorphic core
(HMC), a sequence of high metamorphic-grade gneiss, migmatite, and granite,
in the hinterland of the Himalayan orogen. Sm-Nd isotopic analyses indicate
that the HMC comprises Greater Himalayan sequence (GHS) and Lesser
Himalayan sequence (LHS) rocks. Conventional interpretation of such
provenance data would require the Main Central thrust (MCT) to be also
outcropping within the core complex. However, new in situ U-Th/Pb monazite
petrochronology coupled with petrographic, structural, and microstructural
observations reveal that the core complex is composed solely of rocks in
the hanging wall of the MCT. Rocks from the core complex record Eocene and
late Oligocene to early Miocene monazite (re-)crystallization periods
(monazite age peaks of 40 Ma, 25–19 Ma, and 19–16 Ma) overprinting pre-
Himalayan Ordovician Bhimphedian metamorphism and magmatism (ca. 470 Ma).
The combination of Sm-Nd isotopic analysis and U-Th/ Pb monazite
petrochronology demonstrates that both GHS and LHS protolith rocks were
captured in the hanging wall of the MCT and experienced Cenozoic Himalayan
metamorphism during south-directed extrusion. Monazite ages do not record
metamorphism coeval with late Miocene extensional core complex exhumation,
suggesting that peak metamorphism and generation of anatectic melt in the
core complex had ceased prior to the onset of orogen-parallel hinterland
extension at ca. 15–13 Ma. The geometry of the Gurla Mandhata core complex
requires significant hinterland crustal thickening prior to 16 Ma, which is
attributed to ductile HMC thickening and footwall accretion of LHS
protolith associated with a Main Himalayan thrust ramp below the core
complex. We demonstrate that isotopic signatures such as Sm-Nd should be
used to characterize rock units and structures across the Himalaya only in
conjunction with supporting petrochronological and structural data.

View article:

https://pubs.geoscienceworld.org/gsa/geosphere/article-abstract/doi/10.1130/GES02326.1/595237/Protolith-affiliation-and-tectonometamorphic

Boulder, Colo., USA: GSA’s dynamic online journal, Geosphere,
posts articles online regularly. Locations studied this month include the
western Himalaya, the boundary between the southern Coast Ranges and
western Transverse Ranges in California, the northern Sierra Nevada, and
northwest Nepal.

Marine sedimentary records of chemical weathering evolution in the
western Himalaya since 17 Ma

Peng Zhou; Thomas Ireland; Richard W. Murray; Peter D. Clift

Abstract:
The Indus Fan derives sediment from the western Himalaya and Karakoram.
Sediment from International Ocean Discovery Program drill sites in the
eastern part of the fan coupled with data from an industrial well near the
river mouth allow the weathering history of the region since ca. 16 Ma to
be reconstructed. Clay minerals, bulk sediment geochemistry, and magnetic
susceptibility were used to constrain degrees of chemical alteration.
Diffuse reflectance spectroscopy was used to measure the abundance of
moisture-sensitive minerals hematite and goethite. Indus Fan sediment is
more weathered than Bengal Fan material, probably reflecting slow
transport, despite the drier climate, which slows chemical weathering
rates. Some chemical weathering proxies, such as K/Si or kaolinite/(illite
+ chlorite), show no temporal evolution, but illite crystallinity and the
chemical index of alteration do have statistically measurable decreases
over long time periods. Using these proxies, we suggest that sediment
alteration was moderate and then increased from 13 to 11 Ma, remained high
until 9 Ma, and then reduced from that time until 6 Ma in the context of
reduced physical erosion during a time of increasing aridity as tracked by
hematite/goethite values. The poorly defined reducing trend in weathering
intensity is not clearly linked to global cooling and at least partly
reflects regional climate change. Since 6 Ma, weathering has been weak but
variable since a final reduction in alteration state after 3.5 Ma that
correlates with the onset of Northern Hemispheric glaciation. Reduced or
stable chemical weathering at a time of falling sedimentation rates is not
consistent with models for Cenozoic global climate change that invoke
greater Himalayan weathering fluxes drawing down atmospheric CO 2 but are in accord with the idea of greater surface reactivity
to weathering.

View article:

https://pubs.geoscienceworld.org/gsa/geosphere/article-abstract/doi/10.1130/GES02211.1/595660/Marine-sedimentary-records-of-chemical-weathering

Late Pleistocene rates of rock uplift and faulting at the boundary
between the southern Coast Ranges and the western Transverse Ranges in
California from reconstruction and luminescence dating of the Orcutt
Formation

Ian S. McGregor; Nathan W. Onderdonk

Abstract:
The western Transverse Ranges and southern Coast Ranges of California are
lithologically similar but have very different styles and rates of
Quaternary deformation. The western Transverse Ranges are deformed by
west-trending folds and reverse faults with fast rates of Quaternary fault
slip (1–11 mm/yr) and uplift (1–7 mm/yr). The southern Coast Ranges,
however, are primarily deformed by northwest-trending folds and
right-lateral strike-slip faults with much slower slip rates (3 mm/yr or
less) and uplift rates (<1 mm/yr). Faults and folds at the boundary
between these two structural domains exhibit geometric and kinematic
characteristics of both domains, but little is known about the rate of
Quaternary deformation along the boundary. We used a late Pleistocene
sedimentary deposit, the Orcutt Formation, as a marker to characterize
deformation within the boundary zone over the past 120 k.y. The Orcutt
Formation is a fluvial deposit in the Santa Maria Basin that formed during
regional planation by a broad fluvial system that graded into a shoreline
platform at the coast. We used post-infrared–infrared-stimulated
luminescence (pIR-IRSL) dating to determine that the Orcutt Formation was
deposited between 119 ± 8 and 85 ± 6 ka, coincident with oxygen isotope
stages 5e-a paleo–sea-level highstands and regional depositional events.
The deformed Orcutt basal surface closely follows the present-day
topography of the Santa Maria Basin and is folded by northwest-trending
anticlines that are a combination of fault-propagation and
fault-bend-folding controlled by deeper thrust faults. Reconstructions of
the Orcutt basal surface and forward modeling of balanced cross sections
across the study area allowed us to mea­sure rock uplift rates and fault
slip rates. Rock uplift rates at the crests of two major anticlinoria are
0.9–4.9 mm/yr, and the dip-slip rate along the blind fault system that
underlies these folds is 5.6–6.7 mm/yr. These rates are similar to those
reported from the Ventura area to the southeast and indicate that the
relatively high rates of deformation in the western Transverse Ranges are
also present along the northern boundary zone. The deformation style and
rates are consistent with models that attribute shortening across the Santa
Maria Basin to accommodation of clockwise rotation of the western
Transverse Ranges and suggest that rotation has continued into late
Quaternary time.

View article:

https://pubs.geoscienceworld.org/gsa/geosphere/article-abstract/doi/10.1130/GES02274.1/595661/Late-Pleistocene-rates-of-rock-uplift-and-faulting

Influence of pre-existing structure on pluton emplacement and
geomorphology: The Merrimac plutons, northern Sierra Nevada,
California, USA

V.E. Langenheim; J.A. Vazquez; K.M. Schmidt; G. Guglielmo, Jr.; D.S.
Sweetkind

Abstract:
In much of the western Cordillera of North America, the geologic frame­work
of crustal structure generated in the Mesozoic leaves an imprint on later
plutonic emplacement, subsequent structural setting, and present landscape
morphology. The Merrimac plutons in the northern Sierra Nevada (California,
USA) are a good example of the influence of pre-existing structure at a
larger scale. This paper updates and refines earlier studies of the
Merrimac plutons, with the addition of analysis of gravity and magnetic
data and new 206Pb/238U zircon dates. The gravity and
magnetic data not only confirm the presence of two different neighboring
plutons, but also (1) support the presence of a third pluton, (2) refine
the nature of the contact between the Merrimac plutons as being
structurally controlled, and (3) estimate the depth extent of the plutons
to be ~4–5 km. The zircon 206Pb/238U dates indicate
that the two main plutons have statistically different crystallization ages
nearly 4 m.y. apart. Geomorphic analyses, including estimates of relief,
roughness and drainage density and generation of chi plots, indicate that
the two main plutons are characterized by different elevations with large
longitudinal channel knickpoints that we speculatively attribute to
possible reactivation of pre-existing structure in addition to lithologic
variations influencing relative erosion susceptibility in response to prior
accelerated surface uplift.

View article:

https://pubs.geoscienceworld.org/gsa/geosphere/article-abstract/doi/10.1130/GES02281.1/594115/Influence-of-pre-existing-structure-on-pluton

Protolith affiliation and tectonometamorphic evolution of the Gurla
Mandhata core complex, NW Nepal Himalaya

Laurent Godin; Mark Ahenda; Djordje Grujic; Ross Stevenson; John Cottle

Abstract:
Assigning correct protolith to high metamorphic-grade core zone rocks of
large hot orogens is a particularly important challenge to overcome when
attempting to constrain the early stages of orogenic evolution and
paleogeography of lithotectonic units from these orogens. The Gurla
Mandhata core complex in NW Nepal exposes the Himalayan metamorphic core
(HMC), a sequence of high metamorphic-grade gneiss, migmatite, and granite,
in the hinterland of the Himalayan orogen. Sm-Nd isotopic analyses indicate
that the HMC comprises Greater Himalayan sequence (GHS) and Lesser
Himalayan sequence (LHS) rocks. Conventional interpretation of such
provenance data would require the Main Central thrust (MCT) to be also
outcropping within the core complex. However, new in situ U-Th/Pb monazite
petrochronology coupled with petrographic, structural, and microstructural
observations reveal that the core complex is composed solely of rocks in
the hanging wall of the MCT. Rocks from the core complex record Eocene and
late Oligocene to early Miocene monazite (re-)crystallization periods
(monazite age peaks of 40 Ma, 25–19 Ma, and 19–16 Ma) overprinting pre-
Himalayan Ordovician Bhimphedian metamorphism and magmatism (ca. 470 Ma).
The combination of Sm-Nd isotopic analysis and U-Th/ Pb monazite
petrochronology demonstrates that both GHS and LHS protolith rocks were
captured in the hanging wall of the MCT and experienced Cenozoic Himalayan
metamorphism during south-directed extrusion. Monazite ages do not record
metamorphism coeval with late Miocene extensional core complex exhumation,
suggesting that peak metamorphism and generation of anatectic melt in the
core complex had ceased prior to the onset of orogen-parallel hinterland
extension at ca. 15–13 Ma. The geometry of the Gurla Mandhata core complex
requires significant hinterland crustal thickening prior to 16 Ma, which is
attributed to ductile HMC thickening and footwall accretion of LHS
protolith associated with a Main Himalayan thrust ramp below the core
complex. We demonstrate that isotopic signatures such as Sm-Nd should be
used to characterize rock units and structures across the Himalaya only in
conjunction with supporting petrochronological and structural data.

View article:

https://pubs.geoscienceworld.org/gsa/geosphere/article-abstract/doi/10.1130/GES02326.1/595237/Protolith-affiliation-and-tectonometamorphic

Researchers have confirmed for the first time that Pine Island Glacier in West Antarctica could cross tipping points, leading to a rapid and irreversible retreat which would have significant consequences for global sea level.

Pine Island Glacier is a region of fast-flowing ice draining an area of West Antarctica approximately two thirds the size of the UK. The glacier is a particular cause for concern as it is losing more ice than any other glacier in Antarctica.

Currently, Pine Island Glacier together with its neighbouring Thwaites glacier are responsible for about 10% of the ongoing increase in global sea level.

Scientists have argued for some time that this region of Antarctica could reach a tipping point and undergo an irreversible retreat from which it could not recover. Such a retreat, once started, could lead to the collapse of the entire West Antarctic Ice Sheet, which contains enough ice to raise global sea level by over three metres.

While the general possibility of such a tipping point within ice sheets has been raised before, showing that Pine Island Glacier has the potential to enter unstable retreat is a very different question.

Now, researchers from Northumbria University have shown, for the first time, that this is indeed the case.

Their findings are published in leading journal, The Cryosphere.

Using a state-of-the-art ice flow model developed by Northumbria's glaciology research group, the team have developed methods that allow tipping points within ice sheets to be identified.

For Pine Island Glacier, their study shows that the glacier has at least three distinct tipping points. The third and final event, triggered by ocean temperatures increasing by 1.2C, leads to an irreversible retreat of the entire glacier.

The researchers say that long-term warming and shoaling trends in Circumpolar Deep Water, in combination with changing wind patterns in the Amundsen Sea, could expose Pine Island Glacier's ice shelf to warmer waters for longer periods of time, making temperature changes of this magnitude increasingly likely.

The lead author of the study, Dr Sebastian Rosier, is a Vice-Chancellor's Research Fellow in Northumbria's Department of Geography and Environmental Sciences. He specialises in the modelling processes controlling ice flow in Antarctica with the goal of understanding how the continent will contribute to future sea level rise.

Dr Rosier is a member of the University's glaciology research group, led by Professor Hilmar Gudmundsson, which is currently working on a major £4million study to investigate if climate change will drive the Antarctic Ice Sheet towards a tipping point.

Dr Rosier explained: "The potential for this region to cross a tipping point has been raised in the past, but our study is the first to confirm that Pine Island Glacier does indeed cross these critical thresholds.

"Many different computer simulations around the world are attempting to quantify how a changing climate could affect the West Antarctic Ice Sheet but identifying whether a period of retreat in these models is a tipping point is challenging.

"However, it is a crucial question and the methodology we use in this new study makes it much easier to identify potential future tipping points."

Hilmar Gudmundsson, Professor of Glaciology and Extreme Environments worked with Dr Rosier on the study. He added: "The possibility of Pine Island Glacier entering an unstable retreat has been raised before but this is the first time that this possibility is rigorously established and quantified.

"This is a major forward step in our understanding of the dynamics of this area and I'm thrilled that we have now been able to finally provide firm answers to this important question.

"But the findings of this study also concern me. Should the glacier enter unstable irreversible retreat, the impact on sea level could be measured in metres, and as this study shows, once the retreat starts it might be impossible to halt it."

As an essential material for the survival and reproduction of almost all aerobic organisms, oxygen is closely related to the formation and development of complex organisms. A recent review provides a systematic overview of the latest advances in the oxygen cycle at different spatial and temporal scales and the important role that oxygen plays in shaping our current habitable Earth.

Professor Jianping Huang from Lanzhou University is the corresponding author of the review entitled "The oxygen cycle and a habitable Earth", which is the cover article of the 64(4) of SCIENCE CHINA Earth Sciences in 2021.

Based on summarizing the latest research results of predecessors, the authors of this paper propose a coupling model of the five spheres of the earth system with the oxygen cycle as the core, and clarify the link role of the oxygen cycle in it. In this paper, the authors comprehensively summarized the changes of oxygen cycle and its effect on the habitability of the earth on multiple time scales including modern and geological time, and prospected the future development trend of oxygen cycle research.

"We take O2 for granted because it is just there and we breathe it all the time, yet it took billions of years before there was enough of it to keep animals like us alive." Professor Jianping Huang of Lanzhou University, the corresponding author of the paper, points out, "These processes involve the interaction of various spheres of the Earth system, which are complex interdisciplinary issues with multiple temporal and spatial scales." In this paper, the authors illustrate how the key biochemical processes in the oxygen cycle tie together the various spheres of the Earth system through feedback and interaction. "A habitable Earth gradually formed during the long evolution of the oxygen cycle."

The effects of current human activities on the oxygen cycle and biodiversity are also discussed. "Four of the five large-scale species extinctions that have occurred in the history of the earth are related to the lack of oxygen," Professor Huang concluded, "At present, under the compulsion of human activities, our planet is experiencing a large-scale oxygen reduction, with the ocean deoxygenation as a representative. The oxygen cycle of the Earth system is gradually out of balance, which is very worrying."

Studies of the oxygen cycle cover a wide span of timescales from daily to geologic scales. The oxygen cycles of different timescales dominate the control of atmospheric O2 over the corresponding timescales. However, a distinct boundary that divides the long-term and short-term oxygen cycles has yet to be established, and the complex interactions between the short-term and long-term processes remain unclear. Since the earth system is a highly non-linear and strongly coupled system, a minor perturbation can have the potential to cause a series of dramatic changes. "It is a top priority to connect the short-term and long-term oxygen cycles under a comparable timescale rather than separating them. Effective multidisciplinary cooperation among the subdisciplines of Earth sciences (geology, oceanography, atmospheric sciences, paleobiology, etc.), and social sciences should be promoted to reveal the hidden mechanisms that control the trajectory of the Earth system and how the trajectory may influence the future of human beings." said Prof. Huang. Fortunately, efforts have been made to reverse the decline of atmospheric O2. In China, the Green Great Wall, which was designed to mitigate desertification and expand forests has achieved overall success in past decades. Reductions in carbon emission and its related O2 consumption have been achieved in some major cities around the world.

This study has far-reaching scientific significance and important reference value for understanding the potential link between the oxygen cycle and the biodiversity in geological history and exploring the historical evolution and future of the Earth's habitability.

Long-term, regular use of baby aspirin--at least 15 times per month--prior to a diagnosis of colorectal cancer (CRC) may reduce the risk of death from the disease by limiting the spread of cancerous tumors pre-diagnosis, according to a study led by Cedars-Sinai Cancer researchers.

While previous research has offered consistent evidence that low-dose aspirin use reduces colorectal cancer risk, key findings from the study, published in the peer-reviewed Journal of the National Cancer Institute, revealed that the use of baby aspirin prior to the diagnosis of non-metastatic CRC was associated with a lower rate of metastasis, or tumor spread. Starting aspirin after a colorectal cancer diagnosis was not associated with as strong a benefit as pre-diagnosis use. The researchers similarly found that the use of non-aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, acetaminophen and naproxen, failed to confer those benefits.

"More evidence is needed, but this association between baby aspirin and lower death rates is highly significant," said epidemiologist and lead study author Jane C. Figueiredo, PhD. "These findings may provide an inexpensive lifestyle option to people seeking to prevent colorectal cancer, or to improve their prognoses if they are diagnosed."

Colorectal cancer starts in the colon or the rectum and is the third-leading cause of cancer death for men and women in the U.S., causing approximately 53,000 deaths last year. The American Cancer Society estimates that about 104,600 cases of colon cancer and 43,300 cases of rectal cancer were diagnosed in the U.S. in 2020. Treatment usually involves surgery to remove the cancer, and possibly radiation therapy and chemotherapy.

How Aspirin Works

Researchers believe that differences in the way the aspirin and non-aspirin NSAIDs work affect the medications' differing colorectal cancer survival outcomes.

Low-dose aspirin use irreversibly prevents blood cells called platelets from activating and producing the enzyme thromboxane A2, which allows them to clump together. Tumor cells can attach to these clumps of platelets and spread throughout the body.

"Aspirin inhibits platelet activation, which also could inhibit metastases," said Figueiredo, the director of Community and Population Health Research and an associate professor of Medicine at the Samuel Oschin Cancer Institute at Cedars-Sinai.

Aspirin blocks platelet activation for the life cycle of the platelet. While non-aspirin NSAIDs also inhibit platelet activation, they do not do so permanently, and this could be why a strong association between their use and reduced rates of metastatic disease was not found.

Randomized clinical trials have provided some evidence that non-aspirin NSAIDs may inhibit colorectal cancer tumor formation. However, their association with colorectal cancer-specific mortality has been investigated in only a handful of studies, and the findings have been conflicting.

"Previous studies have not really separated aspirin use from use of non-aspirin NSAIDS," said Figueiredo. "We sought to understand the relationship between aspirin and non-aspirin NSAIDS and mortality in colorectal cancer patients."

Study Details

The observational study conducted by Figueiredo and colleagues included data from more than 2,500 men and women enrolled in the American Cancer Society Cancer Prevention Study-II nutrition cohort. All shared information about their aspirin and non-aspirin NSAID use and all eventually were diagnosed with colorectal cancer. Researchers tracked participants' outcomes from their time of enrollment in 1992 or 1993 through December 2016. While the study did show that participants who began regular aspirin use after their diagnosis had better outcomes than those who did not use aspirin at all, the benefit was not clear enough to be called significant.

Figueiredo said that ongoing clinical trials are examining the impact of aspirin use, before and after diagnosis, on colorectal cancer mortality. When completed, they will provide additional guidance for physicians recommending treatments for their patients. "We have to wait until those results come out," Figueiredo said.

"There are potential harms associated with aspirin use," said Figueiredo. Daily use may increase the risk of allergic reaction and internal bleeding. "There really needs to be a conversation between clinicians and patients about both the risks and benefits. These studies and our results really add to that conversation."

Harvard University researchers have identified the biological mechanism of how chronic stress impairs hair follicle stem cells, confirming long-standing observations that stress might lead to hair loss.

In a mouse study published in the journal Nature, the researchers found that a major stress hormone causes hair follicle stem cells to stay in an extended resting phase, without regenerating the hair follicle and hair. The researchers identified the specific cell type and molecule responsible for relaying the stress signal to the stem cells, and showed that this pathway can be potentially targeted to restore hair growth.

"My lab is interested in understanding how stress affects stem cell biology and tissue biology, spurred in part by the fact that everyone has a story to share about what happens to their skin and hair when they are stressed. I realized that as a skin stem cell biologist, I could not provide a satisfying answer regarding if stress indeed has an impact -- and more importantly, if yes, what are the mechanisms," said Ya-Chieh Hsu, Ph.D., the Alvin and Esta Star Associate Professor of Stem Cell and Regenerative Biology at Harvard and senior author of the study. "The skin offers a tractable and accessible system to study this important problem in depth, and in this work, we found that stress does actually delay stem cell activation and fundamentally changes how frequently hair follicle stem cells regenerate tissues."

The hair follicle is one of the few mammalian tissues that can undergo rounds of regeneration throughout life, and has become a paradigm that informs much of our fundamental understanding of mammalian stem cell biology. The hair follicle naturally cycles between growth and rest, a process fueled by hair follicle stem cells. During the growth phase, hair follicle stem cells become activated to regenerate the hair follicle and hair, and hairs grow longer each day. During the resting phase, the stem cells are quiescent and hairs can shed more easily. Hair loss can occur if the hairs shed and the stem cells remain quiescent without regenerating new tissue.

The researchers studied a mouse model of chronic stress and found that hair follicle stem cells stayed in a resting phase for a very long time without regenerating tissues. A major stress hormone produced by the adrenal glands, corticosterone, was upregulated by chronic stress; providing corticosterone to mice was able to reproduce the stress effect on the stem cells. The equivalent hormone in humans is cortisol, which is also upregulated under stress and is often referred to as the "stress hormone."

"This result suggests that elevated stress hormones indeed have a negative effect on hair follicle stem cells," Hsu said. "But the real surprise came when we took out the source of the stress hormones."

Under normal conditions, hair follicle regeneration slows over time -- the resting phase becomes longer as the animals age. But when the researchers removed the stress hormones, the stem cells' resting phase became extremely short and the mice constantly entered the growth phase to regenerate hair follicles throughout their life, even when they were old.

"So even the baseline level of stress hormone that's normally circulating in the body is an important regulator of the resting phase. Stress essentially just elevates this preexisting 'adrenal gland-hair follicle axis,' making it even more difficult for hair follicle stem cells to enter the growth phase to regenerate new hair follicles," Hsu said.

After establishing the link between the stress hormone and hair follicle stem cell activity, the researchers looked for the biological mechanism underlying the connection.

"We first asked whether the stress hormone was regulating the stem cells directly and checked by taking out the receptor for corticosterone, but this turned out to be wrong. Instead, we found that the stress hormone actually acts on a cluster of dermal cells underneath the hair follicle, known as the dermal papilla," said Sekyu Choi, Ph.D., the lead author of the study.

Dermal papilla is known to be critical for activating hair follicle stem cells, but none of the previously identified factors secreted from dermal papilla changed when stress hormone levels were altered. Rather, the stress hormone prevented dermal papilla cells from secreting Gas6, a molecule that the researchers showed can activate the hair follicle stem cells.

"Under both normal and stress conditions, adding Gas6 was sufficient to activate hair follicle stem cells that were in the resting phase and to promote hair growth," Choi said. "In the future, the Gas6 pathway could be exploited for its potential in activating stem cells to promote hair growth. It will also be very interesting to explore if other stress-related tissue changes are related to the stress hormone's impact on regulating Gas6."

These initial findings in mice need to be further studied before they can be safely applied to humans. Harvard's Office of Technology Development has protected the intellectual property relating to this work and is exploring opportunities for collaboration on its further development and eventual commercialization.

Last year, Hsu's group discovered how stress affects another type of stem cell located in the hair follicle, the melanocyte stem cells that regenerate hair pigment. The researchers found that stress activates the sympathetic nervous system and depletes melanocyte stem cells, leading to premature hair graying. Now with the new study, the two findings together demonstrate that although stress has detrimental impacts on both hair follicle stem cells and melanocyte stem cells, the mechanisms are different. Stress depletes melanocyte stem cells directly via nerve-derived signals, while stress prevents hair follicle stem cells from making new hairs indirectly via an adrenal-gland-derived stress hormone's impact on the niche. Because hair follicle stem cells are not depleted, it might be possible to reactivate stem cells under stress with mechanisms such as the Gas6 pathway.

Beyond the potential application of the Gas6 pathway in promoting hair growth, the study's results also have broader implications for stem cell biology.

"When looking for factors that control stem cell behaviors, normally we would look locally in the skin. While there are important local factors, our findings suggest that the major switch for hair follicle stem cell activity is actually far away in the adrenal gland and it works by changing the threshold required for stem cell activation," Hsu said. "You can have systemic control of stem cell behavior located in a different organ that plays a really important role, and we are learning more and more examples of these 'cross-organ interactions.' Tissue biology is interconnected with body physiology. We still have so much to learn in this area, but we are constantly reminded by our findings that in order to understand stem cells in the skin, we often need to think beyond the skin."

Microbial life already had the necessary conditions to exist on our planet 3.5 billion years ago. This was the conclusion reached by a research team after studying microscopic fluid inclusions in barium sulfate (barite) from the Dresser Mine in Marble Bar, Australia. In their publication "Ingredients for microbial life preserved in 3.5-billion-year-old fluid inclusions," the researchers suggest that organic carbon compounds which could serve as nutrients for microbial life already existed at this time. The study by first author Helge Mißbach (University of Göttingen, Germany) was published in the journal Nature Communications. Co-author Volker Lüders from the GFZ German Research Center for Geosciences carried out carbon isotope analyses on gases in fluid inclusions.

Fluid inclusions show potential for prehistoric life

Lüders assesses the results as surprising, although he cautions against misinterpreting them. "One should not take the study results as direct evidence for early life," says the GFZ researcher. Rather, the findings on the 3.5-billion-year-old fluids showed the existence of the potential for just such prehistoric life. Whether life actually arose from it at that time cannot be determined. Based on the results, "we now know a point in time from which we can say it would have been possible," explains Lüders.

Australian barites as geo-archives

Fluid inclusions in minerals are microscopic geo-archives for the migration of hot solutions and gases in the Earth's crust. Primary fluid inclusions were formed directly during mineral growth and provide important information about the conditions under which they were formed. This includes the pressure, temperature and the solution composition. In addition to an aqueous phase, fluid inclusions can also contain gases whose chemistry can persist for billions of years. The fluid inclusions examined in this study were trapped during crystallization of the host minerals. The fluid inclusions investigated in this study originate from the Dresser Mine in Australia. They were trapped during crystallisation of the host minerals of barium sulphate (barite). The research team analysed them extensively for their formation conditions, biosignatures and carbon isotopes.

In the course of the analyses, it turned out that they contained primordial metabolism - and thus energy sources for life. The results of Lüders' carbon isotope analysis provided additional evidence for different carbon sources. While the gas-rich inclusions of gray barites contained traces of magmatic carbon, clear evidence of an organic origin of the carbon could be found in the fluid inclusions of black barites.

Follow-up research is possible

"The study may create a big stir," Lüders says. Organic molecules of this type have not yet been found so far in fluid inclusions in Archean minerals. At the same time, however, he says the study is just a first step. Lüders says, "The ever-increasing sensitivity of measuring instruments will provide new tools for the study of solid and fluid micro inclusions in minerals. Measurements of bio signatures and isotope ratios are likely to become increasingly accurate in the near future."

By harvesting energy from their surrounding environments, particles named 'artificial micromotors' can propel themselves in specific directions when placed in aqueous solutions. In current research, a popular choice of micromotor is the spherical 'Janus particle' - featuring two distinct sides with different physical properties. Until now, however, few studies have explored how these particles interact with other objects in their surrounding microenvironments. In an experiment detailed in EPJ E, researchers in Germany and The Netherlands, led by Larysa Baraban at Helmholtz-Zentrum Dresden-Rossendorf, show for the first time how the velocities of Janus particles relate to the physical properties of nearby barriers.

The team's discoveries could help researchers to engineer micromotors which can traverse highly complex biological environments. These particles would prove invaluable for cutting-edge medical techniques including drug delivery and nano-surgery. In their study, Baraban and colleagues prepared two types of Janus sphere: the first one with a negatively charged surface, the second, with a positive charged coating. When placed in deionized water, both types generated an ion concentration gradient, and propelled themselves in opposite directions. Nearby, the researchers also placed a glass substrate carrying a variety of charge densities. When both substrate and particle coating had alike charges, the negative particles propelled themselves away from the surface at varying velocities.

For positively-charged substrates and particle coatings, Baraban's team found that these speeds showed a positive correlation with the substrate's charge density. According to the researchers, this behaviour arose since chemical reactions on the positively-charged coatings created their own ion concentration gradients in the surrounding fluid. This generated 'osmotic' flows along the charged substrate, causing the Janus particle to speed up. The discovery is a crucial step forward in our understanding of how self-propelled particles are influenced by the surrounding microenvironment. With further research, this could soon enable researchers to engineer Janus particles with specific speeds and directions, making them better suited to navigating complex environments.

Lakes store huge amounts of methane. In a new study, environmental scientists at the University of Basel offer suggestions for how it can be extracted and used as an energy source in the form of methanol.

Discussion about the current climate crisis usually focuses on carbon dioxide (CO2). The greenhouse gas methane is less well known, but although it is much rarer in the atmosphere, its global warming potential is 80 to 100 times greater per unit.

More than half the methane caused by human activities comes from oil production and agricultural fertilizers. But the gas is also created by the natural decomposition of biomass by microbes, for example in lakes. In their most recent publication, researchers at the University of Basel in Switzerland outline the potential and theoretical possibilities for using methane from lakes and other freshwater bodies for sustainable energy production.

Methane from lakes and water reservoirs makes up about 20% of global natural methane missions. "That would theoretically be enough to meet the world's energy needs," says Maciej Bartosiewicz, a postdoc in the Department of Environmental Sciences of the University of Basel. Lakes continuously absorb CO2 from the atmosphere through the growth of phytoplankton. Microbes convert the carbon, fixed by photosynthesis, into methane when they process biomass. That way, carbon bound in the methane remains within the natural cycle during combustion. Fossil fuels could be partially replaced by "natural" renewable methane. Methane gas is already burned in gas-fired power plants for electricity production and used as a fuel in the form of liquid methanol.

Lakes as huge energy stores

The idea described in the article isn't completely new: since 2016, methane in Lake Kivu between Rwanda and the Democratic Republic of Congo has been extracted from a depth of 260 meters, cleaned and used for energy supply directly via generators. "Methane occurs in high concentrations in large quantities on the lake bed there," explains Bartosiewicz. "The methane concentration is about 100 times higher than in ordinary lakes." Low concentrations made extracting methane from conventional lakes seem too technically difficult until a few years ago. But new microporous membranes made of polymeric materials now allow the gas to be separated from the water much more efficiently.

The researchers have made the first concrete proposals in this regard: using a hydrophobic gas-liquid membrane contactor, a methane-containing gas mixture can be separated from water and the methane concentrated. Zeolite minerals are particularly suitable for enrichment, since hydrophobic crystalline substances can adsorb and release gases.

Potential positive effects on ecosystems

"With our idea, we wanted to start a broad discussion about the potential, feasibility and risks of a technology like this," says Bartosiewicz. "Until now, no studies have addressed the effects of methane removal on lake ecosystem functioning, but no immediate negative effects can be foreseen with our current understanding." However, removing excess carbon could even help curb excessive phytoplankton bloom formation and reduce natural greenhouse gas emissions from lakes. More work is needed before any practical implementation of this initial theoretical idea, says Bartosiewicz. But he's convinced: "This concept could one day make an important contribution to reaching our climate goals."

Scientists from Trinity College Dublin believe they have pinpointed our most distant animal relative in the tree of life and, in doing so, have resolved an ongoing debate. Their work finds strong evidence that sponges - not more complex comb jellies - were our most distant relatives.

Sponges are structurally simple, lacking complex traits such as a nervous system, muscles, and a though-gut. Logically, you would expect these complex traits to have emerged only once during animal evolution - after our lineage diverged from that of sponges - and then be retained in newly evolved creatures thereafter.

However, a debate has been raging ever since phylogenomic studies found evidence that our most distant animal relatives were in fact comb jellies. Comb jellies are considerably more complex than sponges, using a nervous system and muscles to detect and capture prey, for example, and a through-gut to help them digest it.

As such, if they were our most distant animal relatives, it would seem likely that the complex traits they evolved were later lost in simple animals such as sponges, or that they evolved twice over the course of evolutionary history - once in comb jellies and again, independently, in humans, sharks, flies and other related animals that have them.

Anthony Redmond, Postdoctoral Research Fellow in Trinity's School of Genetics and Microbiology, is first author of the research article just published in leading international journal, Nature Communications. He said:

"It may seem very unlikely that such complex traits could evolve twice, independently, but evolution doesn't always follow a simple path. For example, birds and bats are distantly related but have independently evolved wings for flight.

"However, instead of comb jellies, our improved analyses point to sponges as our most distant animal relatives, restoring the traditional, simpler hypothesis of animal evolution. This means both that the animal ancestor was simple and that muscles, and the nervous and digestive systems, although further elaborated upon in many lineages, have a single origin."

A new approach to making genetic comparisons

Comparing genomes to assess how species are related is a lot harder than it sounds. There are multiple different methods for doing so and different methods reach different conclusions - hence the disagreement as to whether sponges or comb jellies are our most distant relatives.

To resolve the debate, the Trinity team developed a new approach to analysing the amino acid sequences that make up an animal's proteins. Their approach reduced the errors associated with the all-important comparisons.

Natural selection to maintain the shape and function of proteins means that any given amino acid in a protein will usually only change to other amino acids with similar biochemical properties during evolution, e.g. like-for-like substitutions with respect to features such as positive/negative charge.

Failing to account for this can lead to errors when reconstructing phylogenetic relationships, which the Trinity researchers believe led to the recovery of comb jellies as our most distant animal relatives in some previous studies.

Aoife McLysaght, Professor of Genetics in Trinity's School of Genetics and Microbiology, and senior author of the research article, said:

"Our approach bridges the gap between two disagreeing methodologies, and provides strong evidence that sponges, and not comb jellies, are our most distant animal relatives. This means our last common animal ancestor was morphologically simple and suggests that repeated evolution and/or loss of complex features like a nervous system is less likely than if comb jellies were our most distant animal relatives.

"This is fascinating in its own regard, but it also represents an important step forward in phylogenomic research. Other researchers had come to different conclusions about our most distant animal relative, and that was the case even when they used the same data - they had just used different methods.

"Our new approach should be useful for similar studies in which scientists try to resolve how certain species are related to each other. This information is crucial to our understanding of evolution and can have important implications in other, related fields, such as biodiversity and conservation science."

A targeted opioid that only treats diseased tissues and spares healthy tissues relieves pain from inflammatory bowel disease without causing side effects, according to new research published in the journal Gut.

The study, led by researchers at New York University College of Dentistry and Queen's University in Ontario, was conducted in mice with colitis, an inflammatory bowel disease marked by inflammation of the large intestine.

Opioids, which are used to treat chronic pain in people with inflammatory bowel disease, relieve pain by targeting opioid receptors, including the mu opioid receptor. When opioids activate the mu opioid receptor in healthy tissues, however, they can cause severe and life-threatening side effects, including difficulty breathing, constipation, sedation, and addiction.

"We wanted to understand whether it is possible to activate this receptor only in diseased tissues and not in normal tissues," said senior study author Nigel Bunnett, PhD, professor and chair of the Department of Molecular Pathobiology at NYU College of Dentistry. "Essentially, can you control pain without triggering these devastating side effects?"

The answer may lie in a novel opioid called NFEPP, discovered by Christoph Stein, MD, of Charité-Universitätsmedizin Berlin, a collaborator on the Gut study. NFEPP is a reengineered form of the opioid fentanyl; an added fluorine atom helps the drug to only bind to the mu opioid receptor in an acidic environment. This steers NFEPP to diseased tissues--sites of inflammation or injury--which become acidic due to changes in the tissues' metabolism.

The researchers investigated the use of NFEPP and fentanyl in mice with colitis, which caused their gut tissue to be mildly acidic. Both NFEPP and fentanyl inhibited colon pain in mice with colitis. However, in sharp contrast to fentanyl, NFEPP did not cause side effects such as constipation, suppressed breathing, and altered movement. In healthy mice without inflammatory bowel disease, NFEPP did not alter pain activity or cause side effects.

"The preference of NFEPP for activating opioid receptors in acidic tissues accounts for its ability to selectivity relieve pain in the inflamed but not healthy colon," said Bunnett. "By sparing healthy tissues, we avoided the detrimental side effects seen with fentanyl use."

The researchers are now collecting tissue samples from people with inflammatory bowel disease to determine whether their colons, like those in mice, are also acidic environments. If so, they plan to test NFEPP's ability to inhibit pain in the human gut and ultimately conduct clinical trials.

"Treatments designed to preferentially engage opioid receptors in diseased tissues could offer the potential for effective pain relief without the side effects. These drugs would represent a major advance in the treatment of painful diseases, including inflammatory bowel disease and cancer," said Bunnett. "More broadly, engineering drugs beyond pain treatments that target only diseased tissues could open the door to more effective and precise therapies for a wide range of disorders."

WASHINGTON (March 31, 2021)-- New research published today in the journal Environmental Health Perspectives from Environmental Defense Fund and the George Washington University shows air pollution takes an enormous toll on health in the San Francisco Bay Area, and the impacts vary dramatically within neighborhoods. The magnitude of the health burden from pollution demonstrates the need for urgent action to cut air pollution and protect health, particularly in areas facing the highest impacts.

The analysis estimated that exposure to particle pollution (soot) resulted in more than 3,000 deaths and 5,500 new childhood asthma cases every year in the Bay Area. Exposure to the traffic-related pollutant nitrogen dioxide also had alarming health impacts, resulting in more than 2,500 deaths and 5,200 new childhood asthma cases every year. While the impacts of these pollutants are not additive, the findings illustrate the massive harm caused by air pollution to adults and children in cities.

These health impacts vary dramatically from street-to-street, and some communities experience a much larger burden. In certain areas, death rates resulting from pollution are more than 30 times higher than in others. And for asthma, while traffic-related air pollution accounts for an average of 1 in 5 new childhood asthma cases across the Bay Area, pollution is responsible for up to 1 in 2 cases in some areas.

Further, using this analysis, Environmental Defense Fund found stark racial disparities in the impacts of air pollution. Specifically, neighborhoods with higher percentages of people of color face, on average, double the rate of pollution-related childhood asthma compared to predominantly white neighborhoods.

"Despite major improvements in air quality in the United States over the last 50 years, air quality has not improved equitably," Susan Anenberg, an associate professor at the George Washington University Milken Institute School of Public Health and corresponding author on the study, said. "Increasing availability of data on air pollution levels and disease rates at the neighborhood scale can help us take action to reduce those inequities."

This health impact assessment makes visible the cumulative impacts of pollution and health disparities at a hyperlocal scale by using air pollution data from street-level mobile monitoring and satellites, combined with local population and health information. These methods can be used in other cities worldwide to evaluate the impacts of air pollution and identify areas to target mitigation efforts where they will have the largest health benefit.

By using local air and health data, this analysis revealed large disparities in the health impacts of air pollution and identified hotspots of impacts that would not have otherwise been recognized. Specifically, using less-detailed health data underestimated the deaths attributed to pollution by up to 50% in Oakland compared to data that captured health disparities within the city. This could have important implications for decision-makers seeking to allocate resources equitably or target areas for air pollution mitigation, particularly because typical health impact assessments do not use local health and air data.

"We find local level datasets, such as the Google Street View measurements and local level rates of disease, help us determine which neighborhoods are at greatest risk," Veronica Southerland, a PhD candidate at the George Washington University Milken Institute School of Public Health and lead author on the study, said. "Without using these datasets, we might miss important disparities in the health burden of air pollution."

This research, supported in part by a NASA grant, builds on Environmental Defense Fund's previous work with Google Earth Outreach and other partners in Oakland, which deployed Google Street View cars to create a large, spatially precise dataset of mobile air pollution measurements within Oakland. This latest research shows how pollution can contribute to health disparities, as it disproportionately impacts neighborhoods burdened by existing health conditions.

"Across the world, people living in cities - from the young to the elderly - are impacted by air pollution. But we know that this harm is not equally distributed," Ananya Roy, Senior Health Scientist at Environmental Defense Fund and a co-author on the study, said. "This study develops methods and shines a light on the major disparities in air pollution's impacts on communities at an unprecedented block by block scale, providing actionable information for decision-makers and advocates."

Increased consumption of flavanols - a group of molecules occurring naturally in fruit and vegetables - could protect people from mental stress-induced cardiovascular events such as stroke, heart disease and thrombosis, according to new research.

Researchers have discovered that blood vessels were able to function better during mental stress when people were given a cocoa drink containing high levels of flavanols than when drinking a non-flavanol enriched drink.

A thin membrane of cells lining the heart and blood vessels, when functioning efficiently the endothelium helps to reduce the risk of peripheral vascular disease, stroke, heart disease, diabetes, kidney failure, tumour growth, thrombosis, and severe viral infectious diseases. We know that mental stress can have a negative effect on blood vessel function.

A UK research team from the University of Birmingham examined the effects of cocoa flavanols on stress-induced changes on vascular function - publishing their findings in Nutrients.

Lead author, Dr. Catarina Rendeiro, of the University of Birmingham's School of Sport, Exercise and Rehabilitation Sciences, explains: "We found that drinking flavanol-rich cocoa can be an effective dietary strategy to reduce temporary impairments in endothelial function following mental stress and also improve blood flow during stressful episodes".

"Flavanols are extremely common in a wide range of fruit and vegetables. By utilizing the known cardiovascular benefits of these compounds during periods of acute vascular vulnerability (such as stress) we can offer improved guidance to people about how to make the most of their dietary choices during stressful periods."

In a randomized study, conducted by postgraduate student Rosalind Baynham, a group of healthy men drank a high-flavanol cocoa beverage 90 minutes before completing an eight-minute mental stress task.

The researchers measured forearm blood flow and cardiovascular activity at rest and during stress and assessed functioning of the blood vessels up to 90 min post stress - discovering that blood vessel function was less impaired when the participants drank high-flavanol cocoa. The researchers also discovered that flavanols improve blood flow during stress.

Stress is highly prevalent in today's society and has been linked with both psychological and physical health. Mental stress induces immediate increases in heart rate and blood pressure (BP) in healthy adults and also results in temporary impairments in the function of arteries even after the episode of stress has ceased.

Single episodes of stress have been shown to increase the risk of acute cardiovascular events and the impact of stress on the blood vessels has been suggested to contribute to these stress-induced cardiovascular events. Indeed, previous research by Dr Jet Veldhuijzen van Zanten, co-investigator on this study, has shown that people at risk for cardiovascular disease show poorer vascular responses to acute stress.

"Our findings are significant for everyday diet, given that the daily dosage administered could be achieved by consuming a variety of foods rich in flavanols - particularly apples, black grapes, blackberries, cherries, raspberries, pears, pulses, green tea and unprocessed cocoa. This has important implications for measures to protect the blood vessels of those individuals who are more vulnerable to the effects of mental stress," commented Dr. Rendeiro.

In Brazil, researchers are puzzling over socioeconomic and environmental indicators that do not add up. They are concerned with what they call the São Paulo Macrometropolitan Area, a mega-region comprising five metropolitan areas in the state of São Paulo with a total of 180 municipalities, some of which provide ecosystem services while others receive them. The problem is that the former, which provide the others with water, food and power generation inputs, suffer from steep inequities in terms of defective human development and lack of social inclusion.

"Urban centers have always been drivers of economic development, but no town or city can sustain life without ecosystem services that assure a supply of inputs as basic as water, power and food. For this to be the case throughout the urban fabric of the Macrometropolitan Area, there should be mutuality among the cities there, but instead our analysis shows major asymmetries that tend to impair or neglect this exchange," said Leandro Giatti
, a professor at the University of São Paulo's School of Public Health (FSP-USP).

Giatti is one of several researchers involved in a Thematic Project on environmental governance in the São Paulo Macrometropolitan Area, and last author of a study published in the Journal of Cleaner Production on phenomena critiqued by the authors as examples of environmental injustice in relations among cities in the area.

The researchers divided the 180 cities into four groups, three of which were considered receivers and a fourth classed as providers. The receivers were in the state capital near the coast or in the interior, and one of these groups was labeled "developed receivers". The providers were as defined above. "Assessment of the development and management of water, power and food is always based on economics, but it's a puzzle because the numbers don't add up. In the area, there are 34 million people who need water, power and food to survive. The industry also needs these factors. It's important to include such complexities in plans to develop the area," Giatti said.

The São Paulo Macrometropolitan Area has some 34 million inhabitants. It encompasses the Paraíba Valley area, and the São Paulo, Campinas, Sorocaba, and Santos Metropolitan Areas. São Paulo state has urbanized steadily since the 1950s, often in a disorganized manner. Demand for blue-green infrastructure has increased dramatically, as have threats to the provision of ecosystem services such as water supply, climate regulation, and soil formation for green-belt food production. Blue infrastructure refers to rivers, ponds, wetlands, floodplains, and water treatment facilities, green infrastructure to trees, forests, parks, and fields. Both terms come from urban and land-use planning.

"Many cities in the São Paulo Macrometropolitan Area rely on increasingly distant sources of water, climate regulation, and soil formation for green-belt food production. This leads to inequities," Giatti said. "The solution is proper planning for the providers of life support. This can take the form of municipal plans or large-scale engineering projects to supply water, power and food."

Winners and losers

São Caetano do Sul and Natividade da Serra are among several examples highlighted by the authors of the study to illustrate the disparity between providers and receivers of ecosystem services. The former is highly urbanized, with very little blue-green infrastructure, but one of the front-ranking cities in Brazil in terms of its human development index (HDI). Natividade is an ecosystem service provider with a tiny population and a very poor HDI.

According to the authors, appraising the combined benefits of blue-green infrastructure in urban spaces is important as an adaptation strategy to improve natural resource management and support for ecosystem processes and functions.

"The study provides a comprehensive understanding of complex urban systems by considering environmental justice and water-energy-food nexus synergies. Its main aim is to appeal to public policymakers. Payment for ecosystem services is often seen as a solution or magic formula, but the trade-offs and side-effects of decisions in this field should always be taken into account. The approach we used to analyze the 180 municipalities in the São Paulo Macrometropolitan Area gave us this more comprehensive picture," said Lira Luz Benites-Lazaro, a researcher at FSP-USP and a co-author of the study.

The researchers used machine learning techniques to correlate 19 socioeconomic and environmental indicators for the 180 municipalities. "The many cities that require more water to generate electricity and to produce food clearly have better quality of life. Those with the worst living conditions were also the ones with the largest amount of plant cover in proportional terms," said Mateus Henrique do Amaral, first author of the study.

Water-energy-food nexus

The study also contributes to a better understanding of complex urban systems based on environmental justice and water-energy-food nexus synergies. According to the UN's Food and Agriculture Organization (FAO), agriculture is the world's largest consumer of freshwater resources, and the food production and supply chain accounts for over a quarter of global energy consumption.

Feeding the world's population, which is set to reach 9 billion by 2050, will require a 60% increase in food production, which will lead to increased water and energy consumption.

The researchers have also conducted studies of the relationship between sugarcane and ethanol using the same approach. "The analysis takes us to a level of discussion of sustainability that's highly compatible with the Sustainable Development Goals [SDGs] in terms of the cross-cutting concerns involved. It's not enough to have a great water management policy if you neglect the requisite energy and food offsets," Giatti said.

Using the water-energy-food nexus as a framework for analysis has become much more frequent worldwide, particularly since the 2011 World Economic Forum. "Actually this approach is much older than that, 700 years old and more. The Incas of Peru planned cities on the basis of this nexus, for example," Benites-Lazaro said.